The HiFi Five Podcast
Welcome to The HiFi Five -- a weekly news magazine and roundtable discussion show about all things high-end audio!
Featuring:
Jay Caceres - Jay's Audio Lab; pre-owned dealer, audio reviewer
Elliot Goldman - Bending Wave USA; high-end audio distributor and retailer
Danny Kaey - Sonic Flare; hi-fi reviewer
Ron Resnick (moderator) - WhatsBestForum; Clarisys Audio dealer; audio reviewer
Our fifth chair will host one-time guests and recurring guests.
This show is going to be a candid, free-wheeling and no-holds-barred behind-the-scenes look at the high-end audio industry. We're going to give you insight, opinions and perspectives. We also are going discuss components and music.
The HiFi Five Podcast
The Hi-Fi Five Episode 25: Measurements for Subjectivist Audiophiles
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Episode 25: Measurements for Subjectivist Audiophiles
Ron Resnick (host/moderator): WhatsBestForum
Brent Butterworth: Wirecutter, Audio Unleased, Audio Journalist
Danny Kaey: EMM Labs, Sonic Flare, HiFi Reviewer
Ralph Karsten: Atma-Sphere
Welcome to the 25th episode of the High Five Five. I'm Ron Resnik. Please like this video. And if you haven't done so so far, please subscribe to the channel. My guest tonight, recurring panelist Danny Kay of EMM Labs and Sonic Flare. I am always delighted for Danny to join me. Brent Butterworth is an audio journalist and measurements expert who reviews and tests audio gear for wire cutter and other publications, and also hosts the podcast Audio Unleashed and has more than three decades of experience evaluating audio equipment. Ralph Carson is the founder and designer of Atmosphere Electronics, known for pioneering reliable output transformerless amplifiers, also makes tube preamps and a great sounding Class D amplifier. Hopefully, Aaron Hardison is going to be joining us later. Aaron is an audio reviewer and engineer who runs the YouTube channel Erin's Audio Corner, where he evaluates loudspeakers using detailed measurements and subjective listening tests. Good evening, gentlemen.
SPEAKER_00Good evening. What's up?
SPEAKER_05Question one. Many audiophiles trust their ears above all else. What is an example of a specific situation where measurements alone can reveal a problem the ear alone can miss? You could be respond with room measurements, equipment measurements. What's an example of a situation where uh measurements can tell us something that the ear may not? Brett.
SPEAKER_04Um there are there are many, many, many, many. Um I would say it's more, it's probably more appropriate to say measurements can tell us things that your evaluation of the product misses because you can hear the things, but a lot of times you don't really uh, you know, in a a lot of times the ways that people evaluate audio gear are are way too casual and they're not methodical. And so they just play the stuff, and you know, it's pleasing or not. But something, you know, for example, with say subwoofers, right? And and I'm I think I'm can qualify as one of the pioneers of CTA 2010 subwoofer outfit measurements. I didn't invent them, but I was one of the two to champion them along with Gene Delasalle at Audioholics. And um that measurement, you know, if you look at a if you get a high-end audio reviewer, a typical high-end audio reviewer to review a subwoofer, they'll review it for uh, you know, they'll kind of talk about how musical it is or something like that. And they also they don't they can't really tell how much their room affects the sound. Whereas if you do the measurement, you can see a lot of times people say, oh, the bass is uneven with some subwoofer, right? Or or some speaker, and then you measure it, and the speaker's flat, right? And the speaker's like properly engineered, but the measurement shows you that it's correct, and the your ear tells you it's wrong, but your ear and your brain don't realize what the actual problem is. So you can fault a product for something that the measurements show is not actually a problem, and the problem is you, not the product. Danny.
SPEAKER_00Um you know, I I was actually thinking about that, and um, you obviously see my alias Spock. Uh and there's a simple reason for that. There's always a simple reason for everything, um, especially when you know me and you watch my shows and you watch my participation here on this channel. I always take forever and a half to get to the point. Um, but in this case, Spock refers to my pair of AirPod Pro 3s from this lovely little orchard uh company in Cupertino, California called Apple. And the specific reason I'm bringing up these AirPod Pro 3s is that you can uh, as of about two years ago, perform a medical grade hearing test uh with AirPods and your iPhone, and it spits out an audiogram that uh you can, for all intents and purposes, take to your um audiologist or or you know, ear throat, um nose specialist or doctor or who whomever you wish to, or just audiophile buddy, and spit out essentially the graph of what you are actually able to hear uh or not. And so I think a lot of times um I I've been using this and I've published my results uh with every review that I actually perform on my channel Sonic Flare. Uh, whenever I do a product review that requires um my input as a reviewer based on the two things I got between my noggins, um, I always publish my audiologist um my audiogram. And uh the truth of the matter is um it reveals a lot about what you can actually hear or not. And so what I'm getting at is if you're plotting a graph that's you know 10 dB down at 10 kilohertz, and someone puts in the super tweeter in front of you that goes up to 50k, well, guess what? You're a cold turkey because you're never ever ever going to be able to hear any of those frequencies. So there you go.
SPEAKER_05That's an answer to a different question. I'm asking, what's a situation where measurements, not of the audiophile's ears, but objective measurements using instrumentation that may uh uh uh uh surface a problem that the audiophile's ears, regardless of their audio, regardless of their frequency response, might miss. How can the measurements help an audiophile understand something that he or she may not be hearing with their ears, whatever the quality of their ears based on the audiogram?
SPEAKER_00I I thought we're talking about model trains here.
SPEAKER_02Not talking model uh Ralph. I I do have something uh to say about this now. Uh if you've been watching the what's best for them. Um I've been making this crusade about how single-inner triodamps can't play bass. And uh I've gotten a lot of pushback on that. People don't like to hear that sort of stuff. But um, you know, here's an example where you can take the amplifier, put it on the bench, and run it up to full power at a thousand cycles per second, then run it down to 20 cycles per second and see what it does. And uh, you know, most single-inner triodamps can't come anywhere near full power. It's more common that they might make a tenth of full power at 20 cycles per second, but a lot of people don't hear it that way, they hear the bass being just fine. So uh, you know, it's and and I I tell you, it's one of those things that uh when you've made this measurement, you really can't unsee it. Um and you know, I've I've put a lot of amps on the bench and and measured them, and this is done with simple equipment. I mean, we're not talking distortion analyzers or anything. I just have a dummy load, and uh, you know, we run it on the abduct full power and with a sine wave, look at it with the oscilloscope, and then just run it down and watch what happens on the scope. Very simple test equipment as far as uh you know test and measurement goes these days. And yet you can see on a lot of amplifiers that as you try to push them into the base, they fall right apart. The single-on triodes are the worst. Um and yet people say they play with great bass. So uh there is a um there's an example for you, and there's a lot more where that came from.
SPEAKER_05Now, if a SAT person hears that amplifier producing bass in his or her system satisfactory to him, does the fact that it shows a falloff on your graph ultimately matter?
SPEAKER_02Uh it does, and here's why. What's happening is that amp, if it's making bass, it's producing a tremendous amount of distortion. And you know, you don't hear the distortion as the amp breaking up or anything like that. What it's doing is it's coloring the sound and it's obscuring detail. If you could allow the amplifier to somehow do what it does at a thousand cycles that it does at 20 cycles per second, you'd hear it sounding dramatically different. It would be more transparent, it would be smoother. Uh, and of course, it would have more impact. So um, but you know, it's always in comparison to what uh I hate to say this, but I feel a lot like it's trying to teach a four-year-old that they have to brush their teeth and how important it is. They've got no idea how important it is.
SPEAKER_05Okay, but brushing teeth is an objective requirement by dentists, is a subjective hobby. So let me ask you this what is your actionable prescription? Is your prescription that people should roll off the SCT amp at 100 hertz and buy amp?
SPEAKER_02If you uh can measure the fact that the amp does do this, you want to find out uh, and all the amps are different. Some have better output transformers than others, and it's the output transformer that's the issue. Now, there's two kinds of single-in-triode amps. There's what they're called series-fed, which is 95% of all SETs made, and there's also a kind called a para feed, which means parallel feed, and they're both referred to how the output transformer is used. The series-fed output transformers are the ones that have trouble playing base, and they're the most common. Uh, and so if you can measure that, yeah, this thing's struggling to make base, you can also see on the scope, you can see that it's also making tremendous distortion while it does so. The waveform doesn't even look remotely like a sine wave. Okay, you'll have something like that. A sine wave goes like this, okay? And you'll see this thing grow out the side and a little dip and stuff. And it's just it's it's ridiculous. So if if you can say, I can see this here, let's roll it off, let's prevent bass from even getting into the amplifier, and find some other kind of amp to play the those frequencies. Now, if you're lucky and you can cross it over at maybe 80 cycles per second, you can get a powered subwoofer to do the rest of it. Okay, and uh because at 80 cycles per second, in most rooms the bass is 100% reverberant because of the waveform's 14 feet long. It's going to bounce around in the room several times before your ear can even tell what the note is. So that's um that would be an example of how you could make the system sound immediately more transparent, more revealing.
SPEAKER_05Okay. Question number two What are the two most useful measurements? Just pick your two favorites that an audiophile can run in his or her room that would immediately reveal valuable, actionable information. Danny, you want to start?
SPEAKER_00Sure. Um, I think the the the baseline, uh, just a regular frequency plot uh would show you particularly in the base where you have a suck out, as it would be shown by incredible dips um that are not normal, I should say, or they're they're abnormal in a sense that they're dramatic dips, which indicates that your room is unable to reproduce that particular frequency. Um and you know, conversely, everything uh uh above the base frequencies uh I think would also indicate uh just the overall performance of your system. The second one, the second measurement, um you know that's a good question. Um I don't know. Fair enough, Brent.
SPEAKER_04I have sort of three, if that's okay. Um what Danny said, I'll I'll agree with Danny, what Danny said, and to do a sweep in your listening chair and see especially what the bass is doing in your listening chair, because then you're gonna see that all the big dips and stuff that your room is costing that your subwoofer probably is not. You can do that measurement, you can move your subwoofer around or move your listening position and find the best place for your sub that way, or for and you and also to fine-tune your main speakers as well. Um, you can also do to get an idea of what your speakers are doing, you can do an averaged M room measurement. And the way you do this is you just do it. There's no there's no scientifically established method of doing this, but like what John Atkinson does, it's stereophile. He does, I can't remember if he does four or six measurements just to like in a kind of listening position, like one here, one here, one here, one here. You can do them uh in different places. If you have a couch, you can do them in different places on the couch, and you average them all, and that should look like a gently downsloping uh response with less trouble and more bass. And if you go to Aaron's website, he's and and his uh YouTube channel, he shows this kind of thing all the time. And the third one is not really a measurement, but it's half a measurement. It's sort of you could say it's a subjective measurement. You can go to using Rumi Q Wizard, you can play the uh CTA 2010 test tones, bass test tones, and this will work with subwoofers with regular speakers or whatever, and you you crank them up, and when you when you hear what these tones do, when you hear what I mean, you know, related to what Ralph was saying, you hear what a say a 31.5 hertz tone does with your sub cranked, or a 25 hertz tone, or a 20 hertz tone, and you start to hear the problems that your subwoofer has, and you start to find the really the engineering flaws that your subwoofer has. And a lot of them may sound fine because you know, frankly, you know, most of the music we listen to doesn't have much content below 40 hertz anyway, right? But if but you're buying a sub because it goes down to 20, right? And so in you know, when you play your organ symphony or whatever, it'll actually do that couch shake. But when you um just like what Ralph was saying, so many of these subs and so many big main speakers have a lot of bass distortion, and when you play these tones, and it won't hurt your your sub or your speaker, right? Because just like a it's a six and a half cycle, uh I call it a womp tone, it goes like womp, womp, womp, right? And there's not enough sustained energy there to like burn out your voice calls or anything like that, and but you can start to hear the chuffing in your port, which you maybe didn't hear, you didn't specifically notice before, but once you hear it, you're like, Oh yeah, it does do that sometimes. Or you'll start to hear if it's got a passive radiator, you'll hear the radiator start banging sometimes. Um, it's sort of I liken it to, you know, you get in a sports car and you drive it around town and you can't tell that much about it, but you get it on a track and you can find out a lot of things about it real fast.
SPEAKER_05Ralph, what are two of your favorite measurements for beginners?
SPEAKER_02Well, I I use pink noise. Uh and uh let's put it this way: if you can't get the bass right in the system, you're gonna have trouble getting the rest of it sounded right uh because the ear has a bit of tone control. Uh if the bass is lacking, uh the system will sound tilted to the mids and highs. If the bass is too much, the system will sound muffled. So you you have to get that foundation right. And uh, you know, I use sub well first. My my main speakers, uh classic audio loud speakers, T3s, right there. Um they're flat to 20 cycles per second. Uh but in this room, there's a pretty significant standing wave right where I'm sitting.
SPEAKER_04Oh well, the standing wave sucked him up. Yeah, it consumed him.
SPEAKER_02Well, yeah, I I I can't talk about the uh apparently uh the the software's chuffing. Okay, so anyway, the point is is that uh you know when you get standing waves in a room, you have to break it up with extra subwoofers. Because my speakers are flat to 20 cycles, I just need a pair, and one's off to my left and the other one's behind me to the right.
SPEAKER_05Ralph, we lost your video.
SPEAKER_02Yeah, okay. Well, that's a do you want me to point at the speaker again?
SPEAKER_05No, I wouldn't want to point at your face.
SPEAKER_02I think it's too much for the uh the hardware to handle. But um, my my point is uh even though I've got this stuff and I can break up the standing waves so I I get even evenly distributed base through the room, uh, it's still not right. I have to take pink noise and then just look at the whole system. And this is amazingly easy to do with uh with an iPad or something like that, because they've they've got pink noise generators built in. You can bring them through the system, place the thing uh at the at the listening position and see what's going on.
SPEAKER_05Okay, Ralph, I'm gonna tell let's talk to somebody else while you work on your video, okay? Because we you all we see is a black screen.
SPEAKER_02Really? I can see myself just fine here.
SPEAKER_05Uh maybe log out of StreamYard and log back in or something, or just try to fix it. I'll give it a shot. Okay. Question number three. If an audiophile wants to begin doing room measurements, what there you go. What is the simplest possible setup in terms of software you recommend, microphone you recommend? What's the simplest setup? Somebody for whom measurements are basically anathema, but wants to get his or her feet wet. Uh Brent.
SPEAKER_00That's it.
SPEAKER_04Um this is uh mini DSP U mic one, and this is like 110, 120 bucks. It's a USB microphone, measurement microphone, and you can uh you use it with Rumi Q Wizard, the free software, and which runs on PCs or Macs. And with just this mic and that software, you can do a colossal amount of measurements with it. I mean, it's got a better. I own piles of measurement gear, and I use this as my SPL meter because it's better than anything else I have. Um it's it's pretty simple to hook up. You know, Rumi Q Wizard is it's pretty, it's very capable. And you know, the more capable the measurement software is, the more complicated it is. So it will take you a little while to to kind of get used to it. But you can do with just this mic and that software, you know, for a hundred bucks or whatever, you can do you can do almost any speaker measurements you want if you have, you know, like a backyard or some kind of a big space to do it in. You can, you know, you can do the measurements in your room, you can do you know, in-room measurements like we were talking about a minute ago. Um, you can there's just so much that you can test with just this little rig. And I just I think all audio files ought to get it because it's you know, it's a hundred something, it's a little over a hundred bucks, and you know, you can go get a mic stand at Guitar Center for whatever they cost. I'm price insensitive about guitar center. I I just resign you know my wallet to Guitar Center, but um you know, and some kind of a decent mic stand, and and you can just go wild for years and years with this. I mean, it's just amazing.
SPEAKER_05The software is incredible. Do you use rew as well?
SPEAKER_00So, yes, uh uh I've used uh ReW as well. I have that exact same mic um that I bought on Amazon. Um, but there is an even simpler uh granted. Again, I I I think to Brent's uh comment earlier, I think the uh the inverse is also true that the simpler your um your setup goes, uh the simpler the measurements become as well. And so I think probably the simple most measure uh simple most uh measurement-centric task that you can perform is that you get yourself a basic SPL meter for you know 10 bucks these days on eBay. Uh, because I I you know, unless it's some super duper high-end calibrated thing, um, I think you can buy an Radio Shack SPL meter, like I said, for $10, $15, uh, probably even at a yard sale, and uh run a you know, get a CD with test tones on it, uh, dump it in your CD player, uh, press play, put your SPL meter in front of you at a standard, you know, defined length or excuse me how. Height and distance from your speakers, keep that the same. Play through the test tones and mark off where the SPL meter is, and you'll see what frequency response you're gonna get. Ralph, what measurement? Again, for for for the simplest task of just getting a frequency sweep across your room, that that's literally all that you could use that for.
SPEAKER_05Ralph, what uh measurement software do you use for room measurement?
SPEAKER_02Uh I haven't been using any, but uh there, by the way, I should mention that there are uh SPL meters available for uh for the phone or iPad. They're you know they're available in the app store. Uh I've uh I've got a couple of the Radio Shack meters. I found them pretty handy, um, mostly for just finding out you know how loud the system was really playing, because uh distortion can cause the system to sound louder than it really is. So it's uh it's useful to to know what what what you're actually doing. But I just use pink noise. I've got a little bike that's about like this that I bought off of eBay cheap and uh has a nine-volt battery in it, and I just hook it up to the system. And once I play the pink noise, I can uh use um uh uh a meter to see what it's doing. Uh so um, you know, it's not not a um I haven't really used any software at all. I should mention if you're going to use DSP to do loom correction, it will not fix a standing wave that is causing a base cancellation. The DSP will simply ask the amplifier to put out more power, the power will be canceled by the standing wave. You can put a thousand watts into that standing wave and it won't get fixed. You have to break the standing waves up. If you have a dip in the low frequencies, you've got to do that with multiple subwoofers. There's no other effective way to do it. If you were to have bass traps, you would find that they have to move dynamically about the room as you're playing music in order for them to be effective. Obviously, that would be uh impractical and dangerous. Uh so the um the upshot of it is uh you you have to have the um uh multiple subs in order to break up bass problems. Uh once you have that, then the DSP uh can do its job properly.
SPEAKER_05Uh for the last three years, ending in November, I have been l dealing with a listening room that I call the Bermuda Triangle of Audio, just endless anomalies and problems. So I wanted to start playing with some room measurement software too. I got REW, I got a little MacBook laptop thing, I got the UMic one microphone, which the reason everybody likes the UMic one microphone is because it's $100. And you load a calibration file that is linked to your particular microphone into the REW. So the audio people think the acoustic people think that that you know that increases the accuracy because your REW program is using an actual calibrated mic and it gets uploaded into the program. So there's a value there. That's why everybody likes this UMic1 mic. Okay, so I did this. My initial feeling was that REW is very sophisticated and it ain't the most intuitive thing in the world, and it's kind of annoying for a beginner to deal with if you don't know what the hell you're doing. So then I got a different program called FuzzMeasure, which is touted as being much more user-friendly, much more intuitive. Unfortunately, that thing doesn't use, doesn't do continuous real-time analyzer where you play the music and the the squiggles go continuously. So that was disappointing with the hell I could. Sorry. So I'm back to REW. I doubled down and really tried to understand it and began to use it a little bit. And ReW, I mean, I see why everybody loves REW, but it is not the most intuitive thing in the world, so you've got to have some patience with it. Now, Brent, REW wants you to use, wants you to connect the computer to the input of your preamp so you're using the signal generated by REW. I found that pretty complicated and I kept trying to use pink noise. Is it valid to use just pink noise played off COBUS through your stereo, or do you really need to use the REW generated tones and signals?
SPEAKER_04Okay. This is a tough topic. So there's if you go just go listen to different pink noise, you'll you'll find that you know pink noise is supposed to be you know minus 3 dB per octave. As you go up, every octave is supposed to be 3 dB lower, right? You would think that's a standard that people could could do, but you listen to different pink noise and it's different. And you know, I I honestly I sounded I kind of jealously protect my pink noise files because I use I want to use the same ones all the time, right? And I've actually distributed them to other people at Wirecutter that are doing audio, and but um I think that the pink noise in in REW is fine. Um, I just use the same files just because I've been using them for 20 years, and that way my measurements are all consistent. But um, but but REW is fine. I should have also mentioned there's a piece of software called True RTA, which costs money. Well, the free version, which is the RTA is in one octave bandwidth, which is marginally useful, and you pay more for the greater amount of resolution, but it's uh it's pretty popular among speaker people because it is really fast and simple to use. You don't I don't know if there's a manual. I've been using it for 20-something years. I don't think I've ever looked at a manual, it's very intuitive. Um I think it's under true audio.com is the website, but yeah, the web, the the pink noise that they have on there is perfectly fine. I would be hesitant to get it off of Kobaz or YouTube because so much of that is intended for sleep, and you don't know it. Could really be brown noise, it could be, you know, it could be white noise. Who knows? Because most of these people don't know, they just think pink noise is is shh, right? And so you really you really don't know if you listen to the if you know go on Spotify or whatever, and you've listened to the different kinds of pink noise or YouTube, and it sounds a lot different.
SPEAKER_05Okay, but if you use when you say the pink noise in ReW, then you do have to go through that process of connecting the computer to the your preamp to use the pink noise inside of REW. Is that what you're saying?
SPEAKER_04Yeah, but you you can also use if you have you can go find some, you know. Uh the the first um the first stereophile pink noise, the first stereophile test disc had really nice pink noise on it, and I think a lot of people that might be where I got mine. I can't remember, it's been so long. Um, but and you know, mine's like calibrated at a certain level, and uh because I had to do a lot of like output measurements and things like that, and but the you can use yeah, the noise on the first stereophile test disc. Um, any kind of a more scientific or audio source is probably fine. And even if you go on YouTube, there's still some decent pink noise on there, but you gotta make sure you're getting it. This is gonna sound stupid, but the guys who like their their YouTube thumbnail is like a sine wave or something. That's even though that's not pink noise, that's probably good because at least they know what a sine wave is. So probably they they used real pink noise. They don't know. I mean, it's a stupid thing to say, but you you gotta you gotta go by something.
SPEAKER_05And so we should be, and just for to be clear, we should be using pink noise and not white noise.
SPEAKER_04Right. No, white white noise. You you you for acoustical measurements you have to use pink noise. White noise can be used for some electronics measurements, but not um not acoustical measurements.
SPEAKER_05Okay. Question number five: can measurements be used to determine whether room treatment is needed or not? And if measurements can be used to determine whether room treatment is needed or not, can it help you figure out where the room treatment should be placed?
SPEAKER_02I have a comment about that.
SPEAKER_05You want to start, Ralph? Sure.
SPEAKER_02Fix the base first. Don't worry about uh treating the room, fix the base first. You can't fix the base without room treatment, you're not gonna be able to fix it with it. You have to put in multiple subs to fix the base if there's a problem. I'm gonna be uh I don't know. I'm I I will repeat myself quite a bit on this uh topic, but once you have that done, then you can accurately use uh the software or whatever to find out what other room treatment you might need. 90% of the room problems are going to be in the base.
SPEAKER_05Okay, so if bass is solved, that's the question. How do you use the measurements or what measurements to use to figure out other things to solve in the room?
SPEAKER_02You know, what I have done uh before there was software, I would just take a tone generator and I would sweep it across the band and I would uh look at um what um the uh sound pressure level meter was reading and uh see if I had any weird peaks in uh in the mids and highs. Uh, you know, uh I haven't had to do that in years. But you know, that's how I used to do it uh because it uh you know you you could see fairly easily what was uh going on at certain frequencies that there was a resonance or something that uh was being uh set off by a certain frequency.
SPEAKER_05Danny, in your studios, when Vicoustic was helping, did you or they use measurements to help figure out whether room treatment is needed, and if so, where it should be placed?
SPEAKER_00Oh, 100%. Yeah. Uh I mean, realistically, really, only up here in Studio A. Um, where when uh when I when I had finished building the room, I almost felt like holy shit, did it just blow all this money for nothing because it sounded absolutely dreadful. Uh, particularly the reverb time was completely off the charts. I mean, slap echo, uh, you couldn't stand in the room for more than 10 seconds without your ears going off berserk. And so, you know, when when I uploaded my um rew file to uh to Vicoustic and they dumped it into their proprietary software or whatever that it is that they use, um they're like, dude, relax, we'll fix it. No, no big deal. And um the reverb time is what really uh was brought down significantly. And uh as a direct result, I mean you can actually listen to music very well here in Studio A. So yeah, absolutely.
SPEAKER_05Brand, how do you use measurements to help figure out whether room true treatment is needed?
SPEAKER_04I will echo exactly what Ralph said. Um, I think that the measurements there are people who will debate this with me who I probably couldn't win the debate. And I'm thinking of Anthony Gramani, who's a you know famous acoustics consultant. Um but I think if you you know you can do the measurements in the base and you can see where your peaks and dips are, you can optimize your sub of replacement, whatever. You can also EQ, you know, you can you can use an EQ with you know people like uh Mini DSP make those and you can run measurements and you can get your bass flat in your listening position and fairly flat across the room. If you work at it, you got multiple subs. I think above the Schroeder frequency, which is where, you know, for those who don't know, um below the Schroeder frequency, your room is like a jug that you're blowing across, it's like a resonator, right? And it resonates at certain frequencies. Above the Schroeder frequency, your room is more like a billiards table and everything just bounces around like crazy, right? So below the Schroeder frequency, you can use measurements and you can get your bass dead on perfect if you are so if you are that dedicated and willing to spend the money. Above it, I don't think measurements are necessary. Um, I don't, you know, if you look at Floyd Toole's book, right? Uh sound reproduction book, um, you know, that's the place where where people actually did listening tests, like blind listening tests with different kinds and and and placements of acoustic treatment. And in his book, his prescription is really quite simple. It's like on your front wall, you know, behind where your main speakers are, you know, have some some thick absorbers, like at least four inches thick, because these little two-inch absorbers just don't absorb mid-range. Um they tend to make everything sound kind of shouty because they're killing the top end of the voices, but they're not killing the main part of the voice, so it just sounds unnatural and awful. Um, so you get you know, four inch thick, at least four inch thick absorbers, you know, foam, whatever, and um on the front wall, and then on the sidewalls, you can sorry on the sidewalls, you can use absorbers at the points of first reflection, which is you know where the the spot where if you took a mirror and moved it along the wall and you're in your listening position, you will see the speaker. That's the way to find your point of first reflection, right? And you can put absorptive treatment there if you want or not. Uh Floyd Tool recommends it for home theater as an option for two-channel. He says, probably not. Um, you put some diffusion in the back, just like what Danny's got there, um, right behind him. Not right now, but the the the weird bumpy thing right there. That's it. Put that stuff in the back. And uh Floyd recommends putting you know an absorber like dead center in the back of your room. And and that's it. It's really it's really quite simple. And I don't think it needs all this colossal amounts of of evaluation. I just don't really believe in it. For the same reason I don't believe in room correction above the Schroeder frequency.
SPEAKER_05Let me ask you for the side walls for the first near reflection. You'd mentioned that Floyd suggests absorption. Is that a rule, in your view, is that a rule of general applicability, or should audiophiles experiment between absorption at that point and diffusion at that location?
SPEAKER_04You could do diffusion. Um, it's and he says it's you know, for two-channel, he's he's reluctant to recommend it. For home theater, he says, yeah, you can do it or not, whatever you like. Um, I would say, uh, I have not tried diffusion there. What's going to happen is the absorption is going to make your room sound deadter. And I'm sure we've all been in rooms where it's there's too much absorption and it's too dead sounding, right? You want your room to have some liveliness and some some actual natural reverberance, and the diffusion will let you get that. So one thing you can do before you well, the the treatment depends on room size, sure. But uh, one thing you can do is you can actually like go to Home Depot, right? And get some um, you know, those concrete forms are like big, giant, thick cardboard tubes. You can cut those things in half or not, or just stack them up and use those as cheap diffusers and try it out without spending a huge amount of money on diffusers. Then if you like them, you can pay for fancy diffusers. And you know, for absorptive material, you can just try hanging some you know thick curtains there and see if you like that. I just I hate to um I hate to tell people to go buy expensive acoustic treatment devices unless they're pretty confident that it's gonna give them the result they want.
SPEAKER_00Yeah, good point.
SPEAKER_04They might not like it.
SPEAKER_02I I I do have a comment about this topic of near field. Uh the ear. Um, when you have uh uh information bouncing off a sidewall, it's it's a short delay time. The ear interprets that as harshness. Uh you need to attenuate it somehow. And this is really one of the better reasons for why you might want to tow your speakers in if you uh don't have plain RF speakers. Um I have horns, they've got controlled directivity, so I can uh they help the the horn can help me uh reduce the uh sidewall reflections. What you want to do is you want to get the sidewall reflection low enough so that the primary thing the ear is paying attention to is what's coming from the speaker, it'll sound smoother when you do that. So, uh, in my opinion, you want to have something absorptive there uh on that first reflection point.
SPEAKER_05Question number six. We've discussed measurements of the low frequencies. Can measurements of the low frequencies show whether a base problem is caused by uh immutable room dimensions by the speakers or by poor subwoofer integration? So when we see some anomalous wave in the low frequencies, how do we figure out what's causing those anomalies?
SPEAKER_04Brent Yeah, well, actually, it's if you have one of these mics, right? You can if you let's say you're you've got a lot of unevenness in the base, it's almost certainly going to be the room, but you can put the mic right up against the woofer on the subwoofer. Don't put it like that close because it's gonna bang into the mic, but you know, put it half an inch out or something like that, and you can actually see what the response curve of the subwoofer is. It's more to do a real subwoofer measurement is much more complicated, right? But you can look at that and see what your subwoofer is actually doing or what your main speakers are doing if you if you don't have subwoofers, right? You can at least get an idea of what they're doing, and then you know, just like the on my podcast, we were talking about a review, somebody did a review of this Clipsh Pro Media system that where the subwoofer measures dead flat, and he was talking about all these you know base anomalies in the system that just aren't there, it's because of his setup. And I will say that you know, most subwoofers, if you measure them, and most most speakers, most woofers, you know, you go look at anybody's woofer measurements, go look at you know Atkinson's or some or or the ones I've done things, um Aaron's, they're usually fairly flat. Wolfers don't have these giant things going on in them, right? So if you're hearing a lot of problems in the base, it's almost certainly your room. Now, if you do a the kind of measurements we've been talking about and you do see a big sort of suck out in the base, that's your room. Unless you have two subwoofers in there and they're out of phase or some weird thing like that. But that's that's the whole thing is you know, speakers, people don't realize how how generally flat woofers are. They have some kind of a response that looks like well, I should go, I don't know which way people are seeing this. You know, it should it should fall down in the base by you know 12 dB per octave or 24 or whatever, but below a certain frequency, maybe 40, maybe 30, maybe 20. Um, you'll see that, and then above that, it's gonna be fairly flat, probably up to 100, maybe 120, maybe more. And so I think that subwoofers get blamed for these problems a lot more than they should be. Now, there are crummy subwoofers. I'm I'm testing one right now that that came with a sound bar, and uh, and and they're really some of them are really boomy and all that, but you're that's a problem with the subwoofer design, and it's like a high Q subwoofer that's where it's a little sub and it's they're trying to get the most output they can out of it, so it's a big hump in the response, right? But we're not I I don't think that your audience is gonna have $300 sound bars, so probably not a problem for them. You know, they have high quality, I'm assuming they have high quality gear.
SPEAKER_00So rent at least $4.99 subwoo sound bars.
SPEAKER_04Yeah, but you but you know, most you go buy subwoofers from SVS or whoever, and they're and they're all they're all really good products. If you have a if you have those kind of subwoofers and you have a problem in your room, the problem's room, not the subwoofers.
SPEAKER_05Danny, Ralph, any thoughts on this one?
SPEAKER_02It's the same thing I've been talking about before.
SPEAKER_05Okay.
SPEAKER_02If you've uh if you've measured the room and you've got Some kind of big dip going on in the uh in the room, it's likely you have a standing wave. Do you understand how standing waves work? Um tell us. Well, you've got the initial base note, let's say it's 40 cycles per second coming out of the speaker. It goes past you. The entire waveform has to go past your ear before you can even tell the note is there. You need a couple more iterations before the ear can tell what note it actually is. By that time, it's bounced off the wall behind you, uh, hit the wall in front of you, it's bounced all over the room. It's at that frequency, it's 100% reverberant. In most rooms, about 80 cycles per second and down. Um if the uh the information is coming by, depending upon how far the wall is behind you and it bounces, it can cancel what's coming in that's at the same frequency. Uh so you know, depending upon the length of the room and where the listening position is, and if you've got regular dimensions, parallel walls, you're likely to have a standing wave at some particular frequency. There's gonna be a base suck out. Um and the only way to fix that is with a distributed base array. Uh, if your main speakers have good low frequency response, you're only going to need one or two subs to break it up, depending upon how the sub is built and how the sub is placed.
SPEAKER_05Question number seven. Many audiophiles look at frequency response graphs and get a little overwhelmed. What's one or two patterns that are easiest to recognize and most useful to fix? Danny, did you ever have occasion to do a general frequency response measurements in the uh Danny Audio Laboratory in Long Beach, out of curiosity?
SPEAKER_00You know, good uh good question. I actually know. I never have. Um actually, no, let me rephrase that. I I did in um in the second part of the room where the YGs used to be set up, um where uh that part of the room was absolutely horrible for base, like there was no base in that part of the room whatsoever. Uh, in fact, the base in that room was um in the bathroom 60 feet away. Um but uh no, in uh for the main main speakers where where the Wilsons were, uh I never ran any kind of a uh uh frequency response measurement um of any kind, really. It just sounded amazing. Sometimes you get lucky. I mean, like I always tell people, sometimes you get lucky, uh, and sometimes you gotta work at it.
SPEAKER_05Brand?
SPEAKER_04So you don't um it it depends on are they doing the measurement themselves or are they looking at a measurement somebody else did?
SPEAKER_05Either way. Take it either way.
SPEAKER_04If they're looking at a measurement they did themselves in their room, um the main, as we keep saying, the main problems that they can find and fix are gonna be in the base, right? You're gonna see really lumpy, you're gonna you're gonna find the standing waves that Ralph's talking about. You're gonna find big giant dips, which you're gonna have to move the subwoofer around, or if you don't have subwoofers, if you don't have subwoofers, you probably can't fix it, um, or get multiple subwoofers, um, etc. etc. So that's the problem that you're gonna find. Although, you know, if it's a if it's an if it's a high Q enough dip, if it's a narrow enough dip, you're probably not gonna hear it. And you know, I don't that's one thing is you can you can get really freaked out by uh running a frequency response measurement and seeing everything below 200 hertz just looks like a big giant mess. Um, but a lot of it you don't necessarily hear. I think if you're listening to music and some notes sound boomy and some don't, then you know you've got a problem. But I don't I tend to not freak out at a lot of problems below 200 hertz. It's nice to fix them, it's always better to fix them. You will hear a difference, but a lot of times it's kind of like uh but when you're looking at other people's measurements, like let's say you know John Atkinson's measurements or Aaron's measurements, um the big problem that that speakers have is like you can EQ any speaker to be flat on axis. Um but when it goes off axis is where the speaker designers make their mistakes. And they might cross over a you know, because the narrower the or the the the broader the driver, the bigger the driver, the narrower the dispersion at higher frequencies, right? So if you got a seven-inch woofer or something, right, eight-inch woofer, it's gonna start to really narrow up at the crossover frequency, right? So if you have a speaker that's got like a seven-inch woofer and a one-inch tweeter, and you got a crossover at 3.8 kilohertz, which is something I saw the other day, um, that speaker is gonna really narrow its response before it crosses over to the tweeter, and it's gonna start to sound like this. And I hate speakers that sound like that. Um, you don't hear it as much nowadays as you used to, but because you know, now we have you know good science and and anybody can afford any speaker manufacturer can afford to do pretty good measurements. Um not that all of them do, but they can, but you know, that's a that's the worst problem in speaker design. And if you see that in a in a measurement, if you see in you know that the well, if the if the on-axis response is all bumpy and crazy, don't buy that. If you did buy it, well, uh, you maybe you can learn to love it. Um, but you know, even if you have a flat response, if the off-axis response is as is all bumpy and lumpy, um these are but but you know, if you've already got your speakers and that's what they measure like, you're just gonna have to get used to it. There's no way to fix those problems.
SPEAKER_05Now you we've talked mostly about dips. When we see on a frequency response curve dips in some portion of the lower frequencies, what if there's a room mode that triggers a huge 10 dB or 15 dB bump, say at 65 hertz or 100 hertz? How do people deal with that?
SPEAKER_02Can I answer that one?
SPEAKER_05Sure.
SPEAKER_02That is also caused by a standing wave. There's something called superposition where the incoming waveform does a peak and then the bouncing back waveform also has a peak at the same point. So now it's it's much larger. It's called superposition. And uh that can be controlled by DSP. Uh, room correction will take care of that very nicely. Also, if you've had multiple subwoofers, you can break up the standing wave and it won't do that.
SPEAKER_05Okay, let me ask you a very specific question. There are plenty of audiophiles for whom any DSP is anathema. I don't happen to be in that category. There are many audiophiles for whom DSP is okay in the base, but still anathema above. What if somebody doesn't what if somebody wants to keep the the general and the full analog signal, the full signal perfectly analog, but is willing to do something DSP-ish in the 150 hertz or 100 hertz or 200 hertz area and below? Is there some particular device that you have experience with that will let its purest audiophile keep the signal above 200 hertz all analog, but do something digital below, say 200 hertz?
SPEAKER_02Ron, I I I don't want to sound like I'm repeating myself, but I'm gonna repeat myself. You have to have multiple subs.
SPEAKER_05Okay. So that's a way to keep it all analog and solve the problem you're saying.
SPEAKER_02That's right. You can do it without any DSP at all. Look, uh DSP and room treatment is great, okay? But guess how much of that it fixes in your room? It's about 5%. Okay. All the base traps that you may have spent money on, you know, all the DSP, 5%. Guess what does the other 95% of fixing the room? No. Multiple subs. Okay, because you gotta fix the base, okay? If you can't get the base right, you can't get the rest of it right, okay? Fix the base, then the room treatment and the DSP can do its job correctly, and you get that full 100%. Okay, but you can get 95% of the way there quite often with having multiple subs asymmetrically placed, and then you may have to spend a little bit of time fiddling with the controls of exactly where the crossover frequency is and the level, but that won't you can do that by ear. It's it's pretty straightforward if you know recordings uh uh pretty well. Um, and you know, in my system, I have a substantial standing wave, as I mentioned earlier, where I'm sitting right now. I can turn the subwoofer amp on and off and really demonstrate how profound this effect is. And you know, by adding these subs, I'm not trying to get it to be any more base profound or anything like that. But my I pay a lot of money for these speakers and they go flat to 20 cycles per second. And if I'm not hearing anything at 40 cycles per second, I'm disappointed. You see what I'm saying? So I have two subs, they break up the the uh standing waves beautifully, and uh the uh the base is evenly distributed around the entire room. There's no place I can stand in the room where the bass is better or worse. Uh when you're running multiple subs like that, then what happens is uh you you get small deviations throughout the room rather than big, huge ones. Now, if you the deviation is uh a third or an octave or less, the ears aren't going to hear it. So that's the deal.
SPEAKER_05Let's take a viewer question. What about sub-speaker integration? What do measurements show? How do measurements show if that's the problem going on? That's really easy.
SPEAKER_02Yeah, yeah, it is. That's it's very easy.
SPEAKER_04You take it. Okay, it's you know, you can just run an in-room sweep at your listening position because the the sub and speaker integration is going to be different in different points of the room depending on where your subs and speakers are, right? Um, do it at your listening position. If you see a big dip, go flip the phase switch on your sub. Um, if you see a really broad dip, right, um, maybe your crossover point is too high. If you see a big lump where you think your crossover position is, your crossover is, you know, probably too. You probably want to turn the crossover frequency down lower on the sub before. It very much of this depends on your gear that you have. Um, if you you know, AV receivers are pretty much out of fashion nowadays, except for the the home theater crowd, which is a shrinking crowd, apparently. And those a lot of those have really excellent tools to integrate your sub. And you know, the home theater guys never seem to have a problem integrating their subs, but the audiophile gear for the most part doesn't have that. But yeah, you can just run a room sweep and look at you know, you know where your crossover point is, right? Um, no matter what you're you're using, you have some inkling of what it is because you can see it right on the sub. Um, oh, I've done articles on this that were that went into more depth, but basically, all the problems are going to be in your crossover region and they're pretty easy to fix.
SPEAKER_05We have another question. Very often we hear that no, no, no, from from acousticians, the frequency response chart tells you some things, but you what you really need to focus on is impulse response. What does that mean? How do we do it on REW and what does it tell us?
SPEAKER_04Oh boy. Um I I am not as excited about impulse response measurements for for room acoustics. What it does tell you is if you have resonances, right? Um an impulse response basically is you send out a pulse, which is a uh it could be a logarithmic chirp, which is a whip, or um an MLS burst, which is just noise, you know, and it basically just gives you what you know it's not used to explaining this. It's basically time versus output, right? So you can look at like you know, so so your bottom line is gonna be in milliseconds, and your your your y-axis is gonna be level, right? So you're gonna see your you know, typically the impulse response on a speaker will be a big peek and then woo, right? Um what you'll find if you do impulse response measurements for acoustics is you'll find typically bass resonances in your room. Um if you are sophisticated and dedicated enough to be using bass traps, bass traps will fix room resonances, but you know, bass traps that work are pretty big. I think you know, Tony Gramani's company makes one that's not real big and it's got like a resonating panel in the front, and it works pretty well. I've used them, um, but I just I think it's kind of it's getting into the realm of stuff that's best left to a professional acoustician, to tell you the truth.
SPEAKER_05Yeah, to do the impulse response, that's a situation where you do need to connect the rew that's on your computer to the preamp so the rew generates that pulse.
SPEAKER_04Okay, yeah, because rew has to send out that tone, which is a which they use the logarithmic chirp, right? You have a whoop or does it go the other way? I can't remember. But um, you know, so and it has to know when it sent the tone out and so that it knows when to expect the tone back, right? And every nowadays with the modern speaker measurement gear, every frequency response measurement is also an impulse response measurement, right? Because what you're really doing is measuring impulse response and doing a fast Fourier transform to get the frequency response. But they're they go back and forth. Like I use Clio as my speaker measurement thing. Um, and with Clio, you can just do a little button of that boop, boop, boop, boop. You know, frequency response, impulse response, frequency response, impulse response. It's the same thing. So, but ReW, well, I was just doing that the other day, trying to come up with some new uh ways to test latency with it, and uh like Bluetooth latency, because you know, Bluetooth is standard Bluetooth latency is like 200, 240 milliseconds, right? And I was trying to develop a measurement for the wire cutter crew that they can do after I retire this year. Um, and I figured out a way to do it, and it's not that hard, but yeah, in Rumi Q Wizard, if you do a measurement, it's an impulse response measurement. You just have to look at it. You just go impulse response, frequency response. It's right there. It even says impulse right there on it. So you can look at that. I just don't think that I somebody really smart could could use that for room acoustics. There's there's guys who are so good with Rumi Q Wizard way better than me. And question number eight.
SPEAKER_00Should loudspeaker manufacturers what what was that? Oh nothing.
SPEAKER_05Should loudspeaker manufacturers aim for a flat frequency response? Dan, you've reviewed a lot of speakers. Do you think loudspeaker manufacturers should aim for a flat frequency response?
SPEAKER_00I think so. I mean, I I think it uh I'm hearing some noise from somebody. Ralph? Yeah, Ralph, Ralph is running uh a test setup right now. No, I'm just kidding.
SPEAKER_05Um Ralph, I'm putting you on mute because we're hearing noise. I think you're running pink noise or something.
SPEAKER_00Speak of the devil. Um no, I absolutely think uh that that it showcases the uh let's call it the cleanliness of the design of the crossover uh and how they you know put the drivers together if it's multiple drivers, etc. So I I absolutely think they they should aim for that. Um do many people do many manufacturers get there? No, I don't think so. But do should they aim for it? I I think so.
SPEAKER_04Brent, what do you think? Anachoic flat response. I think there's a lot of confusion between flat response anechoically, which is you know, if you imagine you just took the speaker and the microphone up a mile high in the air, um, or put them in an anoch chamber, or you know, use a quasi-anachoic measurement system, blah blah blah blah. Um, basically you're getting rid of all the echo, and all you have is a sound going from the speaker to the mic. On axis, that should be flat. There are people who like to put a little twist in there, like Paul Barton, PSB speakers, likes to put like a little 1 dB dip up in the around 2 or 3K or something like that, because he feels it just gives a little bit more natural balance and gets a little bit less high frequency buildup in the room. Uh, and stuff like that is totally legit. You can do a little sculpting with that, you might have a little downturn. And some of it, if you have really small speakers, they might sound better with a little bit of roll-off in the top. Um because that'll kind of if they're if they're base deficient and you roll off the top, it'll sound fuller. And uh, you know, that's very commonly used in speakers like this. My reference speaker right here. They do that all the time. Um, but in a in a good speaker, like what your what your viewers are are, I would assume, gonna buy, right? Those should be very close to flat on axis, and off axis, they should, they in other words, the off the the here I am. The on axis looks like this, the off-axis starts to look like this, and this is the treble side, this is the base side. So it's just a gradual. If you start to see dips in the off-axis response, that means it's gonna start to do this.
SPEAKER_05Ralph, do you think manufacturers should aim for flat frequency response with their speakers briefly?
SPEAKER_01Uh I can't hear you. The sound has been got shut off about five minutes ago. Okay. We're gonna have to cancel you. Sorry.
SPEAKER_05My view actually, purely as a hobbyist, I have never heard a flat frequency response loudspeaker that I personally find natural and emotionally emotionally involving. Um, I think the objective of the loudspeaker designer drives the answer to that question. For designers who are aiming for accuracy, they tend to go for flat frequency response. For designers that have more of a musicality, whatever that means, philosophy, I think they tend to go more for a Harman curve, gently declining as you rise in frequency. That's my my personal view. Danny, music segment.
SPEAKER_00Music segment. All right, let's do it. Um, so we have what do I have? I've got a couple things here. Well, actually, three albums. So um the first one is The Lovely Nina Simone. I put a spell on you. This is the Verve. Um, what is it? The the Verve series that Chad is doing, Acoustic Sounds is doing with Verve Together. I forgot the name of it. It's got a name of it. Um, beautiful Gatefold, all analog mastering. Uh great album uh in and of itself. Obviously, the great Nina Simone at her career height, probably. Um, there are, I think, three or four other titles in this series that they did, I think three titles uh that are equally as good. Uh and so I I highly recommend you get these if you're into Nina Simone. Uh the next one staying with the theme of um uh female vocalists is the great Diana Washington. Uh this is another verve series, so this is kind of like their budget reissue series. Uh, and of course, this is the great record that has uh what a difference a day makes. Now, uh this is also cut analog uh from the original tapes. Um it's an incredibly left right record. I I wish they had done this in mono, frankly, uh, because our voice is all the way to the left, and all the instruments and stuff are all the way to the right. And so So it has a very unnatural sound. Um, so the the mono copy that I have uh brings it all nicely together uh and and is a much better experience, frankly speaking. But then again, this is not unusual for for these 60s, early 60s stereo records to be that way. Um, to have that hard left, hard right pan.
SPEAKER_05And then let me ask you, so which is the pressing you have that's the mono version?
SPEAKER_00Uh it's just an original, came out on Mercury Records um back in the day. When did this come out? Let's see if it says it. Uh 60, 58, 59, 69, 59. Sorry, I need glasses. Ha! Uh 59. Uh came out on Mercury. Yeah, so just get the mono version. Uh, way better, in my opinion, than this uh the stereo reissue. Uh, and then the the last one, which is really cool. So this is um Pino Paladino and Blake Mills. Uh, this is their second collab album that they have done. The first one came out about, I don't know, three years ago, maybe I think right before uh COVID. And uh this is called Um That Was a Dream, or that wasn't a dream, I should say. Uh and phenomenal recording. Um, very sort of uh what do I describe this as jazzy type thing, electronic in some sense. Um, and yeah, just uh great music. Terrific.
SPEAKER_05Uh Brent, any uh music suggestions from you?
SPEAKER_04I do have one, please. I can sort of show it to you. It's um focus. It's um it's called One Mississippi by Eric Bibb, who is a American uh you know, blues slash roots singer who uh decamped to Europe a long time ago, but still makes American sounding music, and it's very um it's blues-ish and acoustic-ish, but it sounds it there's there's certain records that just have acoustic records that just have a kick-ass sound, and this is one of those. Um it's kind of like if you ever heard a song Battery by Metallica that starts out with the classical guitar, but it's like kick-ass sounding classical guitar. That's what this sounds like. It's really good.
SPEAKER_00I'm gonna look that up.
SPEAKER_04Songs are great too.
SPEAKER_00Terrific.
SPEAKER_04Any final thoughts?
SPEAKER_00There he is, Eric Bibb. Nice.
SPEAKER_05Okay, well, thank you very much, gentlemen, for joining me on the show. Oh, Ralph, did you have a final thought?
SPEAKER_02I do have a final thought. Uh basically that uh, you know, if you're a subjectivist in nature and you believe that uh your ears are more important than the measurements, uh uh, all I can tell you is that uh there's not a single audio designer out there who doesn't use measurements. So you might want to think about.
SPEAKER_00And there he goes again. Disappearing into the great void of his base suck out.
SPEAKER_05I don't know what's going on there. Gentlemen, thanks very much. Danny, great to see you, Brent. Great to meet you, and uh, thanks for joining. And uh see you next Wednesday. Bye bye.