Choosing the Right Microphone

How do you decide what microphone to use for any instrument or voice you will be recording? All microphones sound different from one another, which is a wonderful tool at our disposal. Making the right choice will improve your recording, eliminate many problems at the mixing stage, and minimize the amount of processing you need.

In this episode, I talk about why I chose the mics I did on two very different projects. One was a punk session and the other an acoustic singer-songwriter project. I explain why I decided to use a particular microphone, and sometimes suggest alternatives.

Of course, this reflects my style of recording. I don’t expect my choices to be your choices, but perhaps this explanation will help you when it comes time to make your decisions.

In this episode, I talk about microphones from AEA, BeyerDynamic, Flea, Neumann, Royer, and Shure. To be clear, I have no connection with these companies except that I love the mics they make. And I have friends at some of the companies. There are mics from many other manufacturers in my collection, but in these examples, those were the mics I used.

email: dwfearn@dwfearn.com
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Transcript

75 Choosing the Right Microphone                                                          February 10, 2023

I’m Doug Fearn and this is My Take on Music Recording

I would guess that you have accumulated more than a few microphones over the years. Why are there so many different models? Why do they sound different from each other? I have talked about these questions in the past, so in this episode I want to explore why we choose a particular mic for a specific instrument or voice.

As a quick review, here is a very brief summary of the three main types of microphones, based on their operating principle.

We’ll start with the condenser mic, the ubiquitous workhorse for professional recording. It is characterized by a high output, usually a “bright” characteristic that exaggerates the higher audio frequencies, and often features selectable pickup patterns. Condenser mics have active electronic circuitry and require some source of external power.

Next are the dynamic mics, which are usually very rugged, small, and have a lower output level. Dynamic mics are available with either an omni-directional or a cardioid directional pickup pattern.

Last are the ribbon mics, which, technically, are dynamic mics but operate on a different principle than what we commonly call dynamic mics. They are natively bi-directional: they pick up sound equally from both the front and back of the mic. The nulls off the “sides” of a ribbon mic are deeper than any other type of mic. Some ribbon mics are uni-directional. Their output level is similar to a dynamic mic.

And then there are the three basic pickup patterns: omnidirectional mics, which pick up sound equally from all directions; the bi-directional or figure-8 pattern; and the cardioid or unidirectional pattern. There are variations on the cardioid pattern that make the sensitive area in front of the mic wider or narrower.

So, we are in the studio and confronted with several instruments and perhaps one or more vocalists. We have a locker with several mics in the various categories and it is time to pick a mic for each source.

Where do we begin?

Here is my process, which undoubtedly differs from what you do. There are many different ways to approach choosing a microphone for a particular sound, and most of them are valid variations. I don’t expect you to do the same things I do. These are just examples of my way.

 I always start by listening to the instrument or voice in the studio. That way I can get an idea of what the actual sound is like. I can also detect any problems I will likely encounter recording that sound.

Next, I consider how that instrument or voice is going to fit into the final product. You might go in one direction for an acoustic recording, another direction for a rock or hip hop or punk record, and take an entirely different approach when recording a piece of classical music.

How does each instrument or voice fit into the overall picture? Is it a high-energy, driving song? Or a laid-back, quiet song?

Your choices should be based on how everything is going to work best for the ultimate listener. You must also take into account the intent of the songwriter, to make sure what you do always serves the song.

How loud is the instrument? How much projection does the vocalist use?

Will more than one instrument be playing at the same time in the same room? If so, you have to consider how much bleed is tolerable from one instrument into the other mics in the room. Will you need to have the option to later replace one or more of the parts?

What are the acoustics of the studio like? Big and reverberant? Small and dead? Bad and boxy-sounding? Bright or dull? Distinct echoes or diffuse reverberation? Those characteristics will also help you decide what mic to use.

As regular listeners to this podcast know, most of the music I record is acoustic. But not all. I am currently involved in a punk album project, which is quite different from my usual recording. Here is a description of the setup and the mics I chose for that session, and why.

The band is just three pieces: drums, bass, and electric guitar on some songs, with the drummer and bass player also sing. As you might imagine, their playing is very loud and the music is intense.

We decided from the beginning that we would record all the instruments and vocals live, all in the same room. This made the performance very natural for the band. Headphones were not needed.

I was concerned about recording the vocals simultaneously, due to bleed from the nearby instruments. I left open the possibility of recording the vocals later, although I did not want to do that, and the band didn’t either.

I used Shure SM7s on both vocalists. The SM7 has a tight, even cardioid pattern, and can be worked very closely without a problem. The pickup from the rear of the mic is minimum at about 135 degrees. Directly off the back would be 180 degrees, where there is a small increase in pickup. This is typical of most cardioid mics.

The position of the vocal mics would be best if that null were aimed at the loudest sound I wanted to minimize. The mics should be as close to the singer as practical, without getting in the way of playing their instrument. It took some experimenting to find the best location to conform to the various conflicting requirements. The drummer’s vocal mic, for example, had to be close, but it had to not interfere with his playing. While setting up, we tried several configurations, to find the best placement.

The bass player plays bass more like a guitar, with a lot of strumming, and he used an array of effects pedals. My plan was to mic his amp and also take the bass direct. The question was, should I take the direct feed right off the instrument? Or after the effects pedals? Or both?

We started with the bass directly feeding a D.W. Fearn VT-I/F DI, and that sounded great blended in with the amped sound, and we did no further experimenting.

I used an AEA R92 ribbon mic on the bass amp, about 18 inches away and oriented to take advantage of the extreme nulls in the bi-directional pattern to minimize pickup from the drums and electric guitar.

I chose the R92 because it was designed for instrument recording, and it can tolerate high sound pressure levels. The sound of that mic is different on the front and back, which gave me an option, if needed. I set it up with the front of the mic facing the bass amp and that sounded great so I left it that way.

Ribbon mics are fairly rugged, but the ribbon can be damaged by excessive air movement. I didn’t want to put the mic at risk, which is why I kept it 18 inches away, and angled it somewhat to avoid the direct blast from the amplifier speakers. I could tell by the sound and the output level that it was in a safe zone.

Since this is high-energy music, the musicians are physically working very hard. In order to get as many songs done in the session, it was necessary to have everything ready to go quickly and to minimize any changes.

The electric guitar was recorded the same way as the bass, both direct and from the amp. In this case, the direct sound probably will not be used, but we have it in case it turns out to be useful. I used a Royer R122 on the amp, with the nulls placed toward the drums and bass amp.

The R121 is one of my favorite mics for recording instruments. It sounds excellent and is small enough to be inobtrusive when used on acoustic instruments. The sound is reasonably flat across the audio range, and proximity effect is less than with many directional mics.

My standard drum mic’ing is simply an AEA R88 stereo ribbon mic placed a few feet from the kit, oriented vertically. I change the vertical position of the mic to adjust the balance, mostly the kick drum versus everything else.

I decided to try this approach, but with a few other mics to choose from or blend in, just in case.

The R88 is my go-to mic for drum recording because of its beautiful stereo image. There are never any phase issues, like you would encounter with multiple mics. I also use it on piano. The ribbon does not have the pop and blast protection of most mics, so it is unsuitable for vocals unless used quite a distance from the singer. The singer has to stay nearly stationary, to avoid a disturbing movement in the stereo image.

For the snare, I used a Shure SM57 for its small size, ruggedness, and the classic snare sound it provides. 

The SM57 is a workhorse dynamic mic, found in almost every studio in the world. It is inexpensive and does its job very well. It works well on snare and guitar amps. You can get the sound you want instantly. And it probably has the best sound quality for the dollar of any mic you can buy, since it only costs around $100.

I added a BeyerDynamic M160 cardioid ribbon mic placed high and aimed down at the drum kit from about six feet away. This mic ran through a Hazelrigg Industries VLC mic preamp and eq, and into a their VNE compressor. No eq was used. The VNE was set to provide an extreme amount of compression.

Back when I recorded a lot of R&B and disco in the 1970s, the M160 was my standard high-hat mic. It tames the high hat and makes it right up front but not annoying, as a condenser mic might.

The M160 has been used for a long time as a drum room mic. If you have a large enough studio, with excellent acoustics, the M160 might be the only drum mic you would need in some situations.

In this case, I wanted that classic sound, and with the extreme compression, it sounded amazing. Not good enough to use by itself, but blended in with the other drum mics, it added excitement and power to the drum sound.

A Neumann U47fet was placed about two feet in front of the kick drum.

My U47fet is an original version from the 1960s, and it sounds great in many different applications. To my ear, it is one of the best solid-state condenser mics ever made.

Many engineers use the U47fet on kick drum, usually as a second mic in addition to a typical dynamic kick mic. It has ample proximity effect, which adds power to the kick sound.

Since it is a vintage mic, I take care of my U47fet and avoid placing it closer than about two feet from the drum. The R88 usually provides all the kick drum sound I need, but in this case, I wanted to be sure the drum had the impact it should have in the music.

The SM7s on the vocals both had the bass roll-off engaged to reduce proximity effect from the close mic’ing and improve isolation from all the low-end sound in the room.

There is no other mic I have ever used that sounds like the SM7. It has a presence and warmth that has become the standard for many radio announcers and podcasters. The pickup pattern is excellent, and it minimizes bleed from off-axis sounds. It worked better than I expected on this session.

No eq was used on anything. The mics chosen provided just the right tonal balance I wanted. When we mix this project, I will probably use about 4dB of low-Q boost at 10kHz from a VT-5 equalizer on the mix buss, after a VT-7 compressor. And maybe a bit of shelving boost of the low-end, with a corresponding roll-off of the extreme lows, starting at around 30Hz.

So, how did it sound?

The sounds of all the instruments and voices were perfectly appropriate. The high energy of the music was captured very well. The isolation between the various mics was even better than what I expected.

We got good takes on seven songs that first session. Soon, the band will be back to record a few more songs to complete an album.

By the way, all the mics went through D.W. Fearn vacuum tube mic preamps, except the M160 on the drums, which used the VLC, which I designed. In fact, except for the solid-state stages of the Merging Technologies converters, this recording was 100% vacuum tube.

It was recorded in DSD256, which is a very high-resolution format with an 11.2MHz sample rate. DSD uses a different principle for digital recording, which you can learn more about in episode 52 of this podcast from August 2021.

The plan is to mix the album in analog, recording back to DSD for the final release.

For a different example, I’ll explain what I did on another recent session of an acoustic singer-songwriter project.

I have recorded this artist, Corrie Lynn Green, with these studio musicians quite a bit in the past three years, so I have a good idea of what works best.

Not all the songs have the same instrumentation, and the energy level is different, too. I will talk about several different songs, that needed slightly different approaches.

First, an outline of our process in cutting the rhythm tracks. The singer-songwriter plays banjo and she has a powerful voice, even when singing “quietly.” The amount of bleed from her vocal and banjo would be excessive if we recorded everyone in the same room, so for tracking, I have her set up in my isolation booth, which is also the shop where I develop new D.W. Fearn products. It is close to the studio and control room, and has its own mic lines and headphone feeds. The isolation is good.

The other instruments are all in the studio. Our usual instrumentation is acoustic guitar, cello, and drums on most songs. At other times, piano, harpsichord, or mandolin might be included. Everything else is overdubbed later.

Drums in the same small room as acoustic guitar and cello sounds impossible. I have contemplated putting the drums in the shop isolation booth, but it has never been necessary. The drummer, John O’Reilly Jr, knows how to play with acoustic instruments, and although the isolation is not perfect, it is good enough. The bleed actually helps in the overall sound of the tracks.

You can hear a conversation with John O’Reilly Jr in episode 53 from August 2021.

For John’s drums, I use the AEA R88 stereo ribbon as the sole pickup. Occasionally I will add the Neumann U47fet on the kick drum, but I have only used it on one song.

The R88 is a stereo ribbon, permanently fixed in the Blumlein pattern of crossed figure-8s. This is my favorite stereo mic’ing technique, but it does have the potential disadvantage of picking up equally from the back of the mic. Also, the pickup from the sides of the mic is out of phase in stereo, which sounds lovely in an interesting acoustic environment, but can create some odd effects in the mix if there is significant bleed from other sounds off the sides.

I have never had a problem with that in the studio, but it is something to keep in mind.

The R88 was positioned about the same as on the punk recording session. I did not use any other mics on the drums.

Positioning a Blumlein microphone can take some experimentation to get the stereo image just right. We made minor adjustments, left and right, two or three times to get what I wanted. And we moved the mic vertically a bit to achieve the proper balance between the kick drum and the rest of the kit.

Needless to say, this approach requires a drummer that always plays with the various drums and cymbals in proper balance. If that is not the case, then multiple mics on the drums might be the way to go.

The cello was situated about 16 feet from the drums, which is about the limit of my small studio, when the drums are placed at their optimum location for recording. Absorbent baffles we made years ago were arranged to minimize the drum bleed into the cello mic. The isolation is not perfect, but the isolation was fine.

My usual cello mic is an AEA R44. The R44 is an exact duplication of the original RCA 44BX from the early 1930s. It is a truly amazing mic, and my go-to for many situations.

The 44 was placed about 16 inches from the cello, about at the level of the bridge. The mic and cello were oriented to take advantage of the extreme null off the sides of a ribbon mic, to minimize drum pickup.

In this session, Peter Oswald, the cello player, used a pizzicato style of playing, similar to how an upright bass would be played. On some songs, Peter will play some bowed parts. The mic’ing is the same in either case.

Sometimes we do cello overdubs, maybe several in some songs. If there is a cello solo or other featured part, I might use a different mic to differentiate it from the other cello parts. For that, I usually use a condenser mic, typically a Flea U48 or C12.

The acoustic guitar is placed in another part of the studio, about equidistant from the drums and cello. Additional baffles separate the guitar and drums. They are only about 12 feet apart.

The guitarist, Adam Monaco, plays an amazing, old Gibson large-body guitar. It is an unusually well-balanced instrument, across its range. Unlike most guitars that size, it is not boomy in the low end.

However, it is a bit dull sounding. To bring out the highs in this wonderful instrument, I use a pair of Flea C12s, the brightest mics I own. That works perfectly, and compensates for the guitar’s inherent dark sound.

Flea is a small microphone manufacturing company in Slovakia. The craftsmanship and attention to detail in all their mics is extraordinary. They have faithfully recreated the sound of the original classic condenser mics.

I use the C12s in a Blumlein configuration, using the mics’ figure-8 pattern setting. They are oriented vertically and as close together as possible to minimize any phase difference.

A Blumlein pair of mics is essentially omni-directional, with a wide stereo pattern in the front and back, plus an out-of-phase stereo pickup off the sides. In this situation, it is not possible to take advantage of the deep nulls of a bi-directional mic in the usual sense. However, I orient one of the out-of-phase sides toward the drums, which provides a nice airiness to the drum bleed. This ambience is diminished in mono, but otherwise it does no harm to the sound.

There is a null on a Blumlein pair, off the “top” and “bottom” of the mics. This can be useful, but it was not practical in this session.

The C12s are about 18 inches from the guitar. Adam knows how to maintain the correct distance throughout the session, but with other players it might be necessary to check on them any time they have moved.

I record Corrie’s reference vocal and banjo in my “isolation booth,” using an R44 on her vocal and a Royer R121 ribbon mic on her banjo. These tracks are simply for guiding the other musicians and are not likely to be used in the final mix. But I record them as if they will be used, just in case. Sometimes you get an amazing performance that must be used, despite any technical inadequacies. That has not been the case on any of Corrie’s sessions, but you never know. I have used the tracks from the booth for other artists on occasion.

My shop isolation booth has had minimal acoustic treatment. It is a small room, about 18 by 15 feet, with windows on three sides. The floor is carpeted and there is an absorptive suspended ceiling. I did add some 5 by 5-foot square acoustic absorber panels that we built, and that helps compensate for all the glass.

What really saves this room is the diffusion from all the stuff that is in there: two workbenches loaded with test equipment, lots of shelving with bins of prototyping parts, and lots of other stuff like tools and projects in the works.

Consequently, the room sounds a lot better than one might expect. There have been many sessions where the performances recorded in there were perfectly acceptable for the final product. I have recorded drums in there, and although the studio sounds better, the drum sound is quite nice. I use the same R88 setup I use in the studio.

The challenge in this session is keeping the banjo and vocal as isolated from each other as much as possible.

The banjo is a loud instrument, and Corrie’s vocal is equally powerful. The natural balance is quite good, but that might not be the case with all singers simultaneously playing and singing.

I use the natural nulls of the two ribbon mics to minimize the bleed. The R44 is angled to put the null towards the banjo, and the R121 is similarly oriented to minimize vocal pickup. I am often astounded by how much isolation I get this way.

This is the basic setup for cutting the rhythm tracks.

Sometimes we do overdubs of other parts while the studio musicians are here, and other times those wait until a later session.

Later, to replace the banjo part, I use the studio. I often use an R44, but sometimes a R121. The sounds are similar, but the 44 often sounds better to me. Both are entirely acceptable. Corrie has two different banjos, a Gibson Bluegrass version, which is very loud, and a more subtle clawhammer banjo that is quieter and more mellow. I have on occasion used a condenser mic on either banjo, for a very aggressive sound. I have used a Neumann SM69 stereo condenser, in Blumlein on occasion, or a Flea U48.

But the 44 often sounds the best to me. It tames the sharp attack, especially on the Bluegrass banjo.

If the banjo is going to be featured, I use a pair of 44s in Blumlein, oriented vertically.

No matter which mics I use, they are always about 2 feet from the instrument.

The R44 is my standard vocal mic for most singers. It takes a little work for both the engineer and the vocalist, but the sound is worth it to me. The 44 has very effective blast and pop filters built-in, since it was designed to be an announce mic for radio. With a careful vocalist, you can use it as close as about 10 inches. But 18 to 36 inches is better, if your studio acoustics allow. A bad room will have the room resonances and any slap echo become too obvious.

Most engineers find that ribbon mics sound too dull for their taste, but I think that is often because of their constant exposure to condenser mics. If you need more high-end for the vocalist, a bit of eq can make a ribbon mic sound a lot like a condenser, but without the harshness of the condenser.

Because all directional mics have some degree of proximity effect, I almost always roll off the low end with an equalizer while cutting a vocal (or anything else that you need to sound less boomy). My standard for that is a D.W. Fearn VT-4 with 2 to 4dB shelving roll-off, set to the 40Hz position. Other equalizers will need different settings. A shelving curve is my first choice.

The 44 has more proximity effect than any other mic I own. Closer than about 8 inches from anything, the sound falls apart. A good vocalist can use the proximity effect to emphasize parts of the performance, as long as they never get too close.

I do not use a separate pop filter, but that might be a good idea for some singers, if just to keep them from getting too close.

For some singers, I use an M49 or U47. Everything depends on the voice and the song. Sometimes the SM7 is the best choice.

On another recent session with Corrie Lynn Green, the instruments in the studio were drums, upright bass, acoustic guitar, and harpsichord.

For the harpsichord, I started with my standard piano mic’ing, which is a R88 over the bridge of the sounding board. The lid of the piano is removed. The mic is about 8 to 12 inches above the sounding board. That sounds amazing.

For the 1731 harpsichord on this session, I placed the R88 much closer to the sounding board than I do on piano. The end of the mic, which is a null for both ribbon elements, was oriented toward the drums. The isolation was remarkable. I expected to have a problem, since the harpsichord is not a loud instrument. And it has no dynamics, except maybe by the number of notes played at once. No matter how hard or softly you hit the keys on a harpsichord, the volume is exactly the same. That is due to the plucked method of making the sound, as opposed to hammers in a piano.

I used a 44 on the upright bass, which always sounds good. Sometimes I use a ribbon mic plus a condenser on the bass, panned left and right, but with the mics very close together.

For violin I use, you guessed it, a 44. It tames the high-end components of the violin sound when close mic’d. It needs the bass roll-off from an equalizer. I place the mic high and aimed down a bit at the violin, from a distance of 2 to 3 feet.

If I had a room with more interesting acoustics, I might approach mic’ing the violin differently. I would prefer to be farther away, but my room does not support that.

In any mic’ing situation, you should keep in mind the “inverse square law.” This is a physics term for the fact that if you double the distance between the mic and sound, the level goes down to one quarter, not a half. The same applies if you move the mic twice as close. The output of the mic will quadruple.

This is true in theory. In the real world, the change with distance is not quite that much. But the concept is good to remember, because you can improve isolation a lot by moving the mic closer. There are always trade-offs, however, and often having some sense of the recording space adds a lot to the recording. A compromise position is often best.

I do not fear bleed from instruments into other mics. Often it adds to the sound. But it does make it more challenging to replace a part, or add processing to one mic without changing the sound of other instruments that might be picked up by that mic. If you need really good isolation, your choices are mainly recording the parts in isolated rooms – or recording them at different times.

I prefer the energy you get from everyone playing together. But that is not always possible.

Also keep in mind the off-axis frequency response of your mics. Most cardioid mics have very odd frequency response off-axis. On a single sound in front of the mic, this is usually of no consequence, although if there is a lot of room sound, it might make the room acoustics sound bizarre.

If there is bleed into a cardioid mic from other sounds, the off-axis response may add some unwanted coloration to the bleed. That can ruin the overall sound.

Bi-directional ribbon mics generally have very uniform frequency response off-axis. The sound does not change, just the level goes down. Any bleed from other instruments sounds much more natural.

Almost always, I use my multi-pattern condenser mics in the figure-8 pattern. That provides many of the same advantages of deep nulls, and more uniform off-axis frequency response, that you get with a ribbon mic. And I like the sound of the mic better in that pattern.

That gives you some insights into my mic’ing techniques. They aren’t for everyone, since we all have our own preferences and style. These are examples of how I get the sounds I prefer. Your desired sound is probably different from mine, which is as it should be.

You can comment on this or any other podcast episode by sending me email at dwfearn@dwfearn.com 

I always like to hear your perspective, your ideas, and your suggestions for future episodes.

And please subscribe to this podcast wherever you get it. A subscription actually helps other people find my podcast.

Thanks.

This is My Take on Music Recording. I’m Doug Fearn. See you next time.