Single-Mic Recording

Using a single microphone, or one stereo mic, to record a musical performance all at once without any overdubbing can result in a recording that is very compelling to the listener. When everyone is performing in the same space at the same time, usually without headphones, there is a musical interaction that occurs that we often lose in the typical session using lots of mics, extreme isolation, and many overdubs.

It’s not for every song or composition. Some music benefits from the usual recording approach. But with a group of players who can play in perfect balance, the result can be amazing, both musically and sonically.

It’s an approach that pushes your engineering talents to their limit. You are doing all the tracking and mixing at the same time, with no ability to change things later.

It is also very demanding of the performers, because if anyone makes a mistake, the take is ruined. But I think the results are worth it, for those situations where it makes sense.

In this episode, I describe several approaches to single-point pickup recording, including a hybrid method that combine single-point with traditional techniques. Some examples can be heard in the releases on the Outer Marker Records label. Here is the link where you can listen to examples:

https://www.nativedsd.com/label/outer-marker-records/

And here is the link to a video that compares both a single-point pickup plus the traditional multi-mic, multi-track method, recorded simultaneously:

https://www.youtube.com/watch?v=7eLP1G4LnM0

email: dwfearn@dwfearn.com
www.youtube.com/c/DWFearn
https://dwfearn.com/

Transcript

99                           Single-Mic Recording                                      December 2, 2024

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

 Have you ever used just one microphone to record everything at the same time? That’s single-mic recording and that was the way everything was recorded in the early days.

Actually, I prefer the term “Single Point Recording” to single-mic, because most of the time the recording uses a stereo microphone, or a pair of microphones. That term also includes the use of a multi-element mic for an Ambisonic recoding.

The idea is that all the sound from all the instruments and voices will be picked up at a single point. That point is determined to be the best choice for the balance of all the sounds, and the ratio of direct sound to room sound.

Multi-track recording relies on many individual mics on isolated tracks capturing multiple sounds simultaneously. This has many advantages, chiefly that you can balance and manipulate the instruments later during a mixing session. That’s a great choice for most music. It also permits overdubbing parts. It gives the producer and engineer a great deal of control over the sound and the impact of the final recording.

So, why would you want to sacrifice all those advantages for a single-mic recording? There are several reasons.

One is that musicians performing together at the same time, in the same room, are often most comfortable that way. Their performance may be more compelling and inspired, just from having the other players to interact with in real time. That is the core of music, historically. It is only in the last 60 years that modern recording techniques have largely eliminated ensemble playing. And playing to together is still is the way most people would prefer to make music if they had a choice. The performance has an energy and cohesiveness that is difficult to achieve using contemporary recording techniques. Today, many engineers want total isolation between each instrument.

A track with one instrument, totally devoid of any sound from any other instrument has advantages. You can equalize, compress, pitch correct, or use other processing or effects without affecting the sound of anything else in the song.

If the performance is less than perfect, the performer can re-record their part later, working on it until it becomes perfect. Of course, technical perfection does not mean the performance is guaranteed to have optimal emotional impact on the listener.

Single-point recording has many challenges. Probably more challenges than most performers and engineers want to deal with.

First, everyone has to play perfectly on the take. Well, there is no such thing as a perfect performance or recording, but the musicians cannot make any glaring errors. There is almost never a situation where you can correct the performance later. What they play is what you get.

This puts pressure on the performers, which can be challenging for someone accustomed to refining their performance through multiple takes, punching-in, or editing together a single performance from multiple takes.

Achieving the proper balance of all the instruments and voices can be a frustrating process for the engineer, and tiresome for the performers. It can take considerable time experimenting with the placement of the single mic, and the position of the performers, to get it right. The larger the ensemble, the more time it is going to take.  And that means that once that perfect balance has been achieved, everyone has to stay exactly on that spot determined to be best for them, and perform their part at the same level, every time.

So, once again, why would you want to do this?

The primary reason, in my mind, is to capture that true essence of music-making. Everyone playing together, seeing each other, and interacting as they play. That can result in a synergy that adds additional impact to the performance.

Another advantage is the unique sonic character of a single-point recording. In stereo, when done properly, there is an uncanny sense of being in the same room as the performers. You can easily visualize where everyone is standing. And you get a strong sense of the space where they are making the music.

That sense of space can also be challenging. If you have a big room with nice acoustics appropriate for the music, the sound will be amazing. But in a poor acoustic environment, it is going to sound just as bad as the room sounds. Multi-mic recording uses close mics for each instrument and voice, and that minimizes the contribution of the room.

In a multi-mic recording typical of most recording today, problems can be introduced due to the difference in the time it takes for a sound to reach multiple microphones. Over short distances, say less than 10 feet, these are mostly perceived as phase differences. An astute listener may be aware of the phase problems, which can feel uncomfortable. The listeners may not know why they are uncomfortable with the sound.

It also means that localizing the sound is more difficult. The location of a sound is indistinct and hazy. That might not matter on many musical sounds, but it could be a major distraction on a featured instrument or voice.

Greater distances between sound sources will often be heard as distinct echoes in a multi-mic session. That requires a very large room. It can sometimes sound amazing, but other times it muddies up the music.

And although the vast majority of people will hear your recording in stereo, not everyone will. If they are listening on a clock radio type device, for example, it will probably be in mono. The out-of-phase components of the sound will cancel out, probably only partially. But the balance of the instruments will be lost. The same applies in places like stores or restaurants, which usually only have a mono feed to their multiple speakers.

The single-point recording can have no phase problems with just one mono mic. And even with a stereo mic or pair of mics, there will be minimal phase cancellation – if the right mic’ing technique is used.

Let’s look at an example of a single-mic recording. In this session, we have four players, a lead vocalist, and a couple of harmony singers, one of which is also playing an acoustic guitar, and an upright bass player. Conventionally, we would isolate each instrument, perhaps some of them in booths, so there is no hint of any other instrument on their track. If someone plays and sings simultaneously, they can record one or the other part initially and overdub the other later.

Or you can record each part separately, building up the song from adding each component, totally isolated because they are recorded at different times. Or different days. Or even in different studios.

But we have them all in the same room. There is no such thing as isolation. We have to get it to sound right from the start, since there is no changing it later.

The first consideration is where to place everyone. Where in the room will you put everyone? We all know our recording space sounds better in some locations than in others.

This will also depend on the mic’ing technique used. If you use a coincident pair of microphones, you need to understand their pickup pattern. Coincident means the mics are as close to being in the same place as possible. Typical coincident stereo mic’ing techniques include X-Y, M-S, and Blumlein. You can learn more about those configurations from my episode on stereo mic’ing.

Other common techniques are what I call “near coincident,” because the mics are close but not in the same spot. ORTF and Decca Tree are two examples of those. They are not as phase-error free as X-Y, M-S, or Blumlein, but the problems are minimal.

Spaced microphones can sound amazing, but that approach will always have some serious phase problems. The mics might be many feet apart, and the phase difference can be significant. That is worst when the mics are very close to the sound, and diminish somewhat as you move the mics farther away. “Near” might be a few feet, and distant might be 25 feet or more. The greater distance likely would only be optimum for a large group, like an orchestra or large choir.

Coincident mic’ing usually uses mics with a cardioid pickup pattern. They predominantly pick up only sound from in front of the mics. The off-axis sound is often strange, because of the lack of directionality the higher the frequency, so the reality is often quite different from what you might expect.

With X-Y, or M-S mic’ing the performers will have to be in front of the mics. That can be very good at sounding like a stage performance, with the instruments and voices across the stage. What you will hear is an accurate representation of how the performers are arranged.

With that approach, thought should be given to how it is going to sound to the listener. If the lead vocalist is on one end of the line of performers, his or her voice is going to come from that point in the stereo soundstage. Probably not the best idea. Arrange the performers like you would pan their track in a stereo mix.

The balance between the instruments and voices will depend on how far they are from the microphone. The general rule is to put the quietest sounds closer and the louder sounds farther away. But that can create its own problems.

The more distant instruments will have a more distant sound to them, depending on the room, which may or may not be appropriate.

And remember the inverse-square law which states that if you double the distance from instrument to mic, you will get about one-quarter the level. Conversely, if you halve the distance, the instrument will be four times louder. When the mic is close to the performers, small differences in distance may result in much larger changes in balance than you might expect.

Ideally, the sound of the ensemble will be well balanced in the room. That makes it much easier to get the right recorded balance. But what if the levels are incompatible? Maybe you have a drummer playing on an acoustic song. Unless the drummer can play at a level compatible with the other instruments, it is going to be a problem. Some drummers can do this. It takes experience and practice. Most drummers find it difficult and uncomfortable to play that quietly. That is something that should be determined before the session. It’s possible you will not be able to make it work, no matter how far away you place the drums.

If there is an electric guitar, will the player need to play loud to get the sound he wants? Is there a way around that? Maybe some sort of attenuator in the speaker line will allow the amp to run at high level, while the sound out of the speakers maintains the “loud” character or the amp, but at a much lower volume.

You can imagine many more situations where a single-point pickup will require some work to make it sound good. It is not a technique for every situation.

My favorite way to make a single-point recording is to use the mics set up in the Blumlein configuration. That’s two bi-directional mics at right angles, typically one above the other and as close together as practical. The patterns are each a figure-8, which means the mics are equally sensitive from the front or back. With two of them at right angles, it would appear that you would have an omni-directional pattern that picks up sound from any point around the mics.

But there is a hidden flaw in this. Since the front and back of a bi-directional mic are opposite phase, the pickup from the “sides” of the mics in Blumlein are completely out-of-phase. In other words, the side quadrants are not useable for picking up the instruments.

Only the front and back of a Blumlein pair are in phase. There is a wonderful stereo pickup in front and another identical one in back of the mics. As you get closer to the sides of the overall pickup pattern, there will be more and more out-of-phase component, until you get to the exact 90-degree point where the pickup will be entirely out-of-phase and cancelled out.

Even in stereo, the out-of-phase side pickup will sound spacy and your hearing won’t be able to localize the origin of the sound.

Blumlein is a terrific way to record in stereo, but you must recognize this problem with the sides.

If you have a room with a good sound for the music, there will be pickup of the room off the sides. That actually sounds good to me most of the time, since it adds a spaciousness to the room sound that is unique to Blumlein.

Getting back to our session, we set up the performers in front of the Blumlein pair of mics, but avoid the sides. The instruments are arranged as you would as if you were panning individual tracks in a stereo mix.

You can use both the front and back of the Blumlein mic for recording. But the left-right is opposite on the back of the mic, so keep that in mind when arranging your performers.

Lead vocals need to be centered, or nearly so, in the stereo field, so start there. Position the other instruments as you would pan them. Make your best guess as to how far away each should be to achieve the right balance.

That may not be the same arrangement as the performers might use on stage when performing live. Often, there may have to be some compromises in the layout so that everyone is comfortable.

And then listen to what you get. It almost certainly will not be optimum. Despite our best, logical estimation of where everyone needs to go, it is often a surprise when we hear it.

Now is the time for experimentation, as we move people around to achieve the panning and balance we want. Just like in a mix session, there may be a variety of ways that work, some much better than others.

The influence of the room will be greater in single-point recording than it is with multiple close mics. Instruments and voices will almost always be a lot farther from the mic than it would be with conventional mic’ing. You are going to hear more of the room than you are used to. That’s great if the room sounds good, and the room reverberation time is appropriate for the music. But if you have a room that does not sound good when mics are more than a foot or two from the sound source, it will probably not be optimal for single-point recording. If your room does not sound great, you might want to review my podcast episode on Improving Acoustic Spaces. You can improve the sound of almost any room with the proper use of sound absorbers and diffusors.

An alternative is to record on location, in a nice-sounding space. This is feasible since there is just one mic, or pair of mics, going to two recording tracks. The amount of equipment and the setup time is minimal.

OK, we are happy with the mix. Let’s hope the setup process didn’t take so long that everyone is tired of the song and would prefer to go home. You won’t get the best performance out of tired people.

If you have the luxury of time, you might want to devote one day to finding the optimum studio setup, and come back the next day for the actual recording. Mark the location of each instrument and vocalist with pieces of tape on the floor.

Coming back the next day should help everyone play and sing at their best. But you have to be ready to be flexible. Even after spending a lot of time refining the setup, the players may be excited to start recording as soon as you get the mix just right.

The decision to stop experimenting and start recording has to take into account whether the setup is good enough vs the additional fatigue experienced by the performers. Perfection is hard in the real world.

But some of the things that may seem less than ideal may not matter in the long run. Capturing a great performance will usually outweigh the minor technical deficiencies. There are times when I like the rough and unrefined sound of a single-point recording for its sense of spontaneity. That may appeal to the listener, too.

Now it’s time to get the best performance. Since the players have played the song or songs multiple times by the time you are ready to hit record, they are probably close to their optimum take. Hopefully they are not beyond the point of best performance.

The results can be stunning. There is the wonderful feeling of real music-making in the recording, and an uncanny sense of being there in front of the performers. The players often sound like they are having fun, and that enthusiasm will affect the listener, too.

What types of music and ensembles is this best for? Well, people that usually play together in the same room, without headphone or stage monitors, often adapt to single-point recording easily and with enthusiasm. Make sure they understand the limitation and challenges before the session, and the potential benefits.

Some players are more comfortable wearing headphones when they play, but usually it is better to not use any headphones at all. Without headphones, people have to listen to each other in the room, and that usually results in better ensemble playing.

I have done many single-point recordings in my career. Some were easy, like a string quartet. Another project I did with a group of four musicians who play modern Indian music was easy. They often sat in a circle to play or perform. I just had to find the best point for the mic. I had to modify their positions slightly to keep instruments out of the out-of-phase nulls of the sides of the Blumlein mic.

Other easy ones were recording a solo piano, harpsichord, guitar, or cello.

Others took more work, like an acoustic group with a singer. In one case, documented on my YouTube channel, there was a singer who also played acoustic guitar, an upright bass, a piano, and a drummer who played just high-hat and bass drum while also playing a dobro. It took over an hour of experimenting to get everything just right. The piano balance in the mix was the most challenging. But the result was very good.

On that project, I also recorded everything with multiple mics in a conventional setup. You can hear the comparison of the two techniques on the video. The link is in the description.

Classical music is an obvious choice for a single-point pickup recording. An orchestra will have a good balance built into their performance, and due to the size of an orchestra, the recording will be made in a large space or concert hall.

Some classical music fans prefer the sound of mics on each section or even on each instrument. That can work well, too. It’s like close mic’ing each individual drum. That perspective is impossible in the real world. Many classical recordings are made with a hybrid approach, with a main single-point stereo mic, plus various section mics or mics on soloists.

And you can also use that hybrid approach effectively when recording a pop ensemble of any genre.

You might record individual instruments, or sections, using a single-point pick-up. For example, you might record the drums with one mic, a horn section with another mic, and so on. Everyone is still playing at the same time, and you have some control of the balance in the mix. Many recordings were made this way in the early days of stereo recording of pop music.

My favorite drum sound uses just one mic – a stereo ribbon in Blumlein. The mic is about 6 to 8 feet from the drums, vertically about even with the top of the kick drum, and aimed towards the snare drum. The balance between the kick drum and the others is adjusted by moving the mic up or down a bit. The farther out you can place the mic, the easier it will be to obtain a good balance. It will take some experimenting to find the best spot for the mic. And even with the same drummer and drums, the optimum location will probably change with different songs.

The result is a very natural sound to the drums, with a nice stereo spread. But most of all, it adds an excellent sense of presence to the drums. The lack of phase problems with multiple mics is gone, and the sound is more cohesive.

It does require a drummer who plays with excellent balance between all the drums and cymbals.

Sometimes I add an additional mic or two, on the snare and kick drum typically, if the music requires that sound. Sometimes I use the extra mics in the mix, and sometimes not. Or I add in just a small amount of the separate mics.

Recording overdubs with more than one instrument or with multiple voices, can be done as a single-point recording. This approach often works well by giving the various performers a sense of depth in the sound stage. This works great for background vocals. But I have also done that when I have two completely different instruments, like percussion and an electric guitar overdubs. I discovered this technique at a session where we were nearly out of time but had two more instruments to add. The stereo mic was already set up. It was the most expedient way to accomplish the task in the least amount of time. I stationed an assistant in the studio to move the mic and players as needed. It only took a  few minutes to get the balance right.

The result was one of my favorite sounds ever. There was a nice sense of the room. It pushed the overdubbed parts into a depth well behind the featured instruments. Everyone involved was amazed at how three-dimensional the final mix sounded.

As I record this episode, our record label, Outer Marker Records, has 10 albums released, which are digitally distributed by Native DSD, and some on vinyl. Four of them are pure single-point recordings, four are recorded with just two stereo mics, and two use the hybrid approach. You can listen to them on Native DSD’s web site. The link is in the description.

One of the first single-mic recordings I did was entirely spontaneous. It was a band with two keyboards, drums, bass, two electric guitars, a horn section, and all of the players also sang. This was for an album project for a major label with a famous producer. The band wanted to make a recording for the producer, as a tribute and thank-you as we neared the end of tracking.

There was a U87 set up for vocals in the approximate center of the room. The musicians played and sang the song and I recorded the performance using just the U87, which I set to omni-directional. We had to move players and around a bit to get the proper balance between the vocals and instruments. We only had a short time to do this, because the producer was due to arrive and the band wanted this song to be a surprise. We did one take.

Everyone loved it. The balance was not perfect, and there was more room sound on some instruments and voices than I would have liked. And it was mono. But it was compelling because of the enthusiasm of everyone involved. The single-mic recording captured that.

The producer was touched when we played it for him as we wrapped up the tracking. I made copies for everyone, including myself. I would play it for you but the recording has been lost to time.

If an appropriate situation arises and you want to try single-point pickup recording, I urge you to do it. It is an interesting challenge that will put all you engineering know-how to a test. The results may surprise you.

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