Too many SM58's in close proximity problem?

[Sayen]

I'm trying to settle a debate with a client, and Google was not helping me today, nor was Shure's website, although that could be user error. For a small vocal group insisting on using SM58s as a distance - which I already know is not ideal - what happens when additional 58's are added in?

So, say you have a group standing in a 3' by 6' box, 3' from a pair of mics. Obviously not ideal, but bear with me. What happens as you go from say, 2 mics, to four or five?

 

[JHWelch]

Well from my knowledge, adding additional microphones would not particularly increase their range. If anything, it would allow you to put the microphones closer to them and allow several of them to focus on each microphone.

However, 4 mics at a distance and 2 mics wouldn't really change anything if they are all facing the microphones. If they are all facing straight forward, 4 mics spread out I guess would pic up more sound.

Any chance of getting mics more suited to the situation?

 

[pmolsonmus]

What happens as you go from say, 2 mics, to four or five?

Phase cancellation is the answer to that question. Check the WIKI or search, re: mics more is not better nor automatically worse. But the same sounds hitting different mics at different times will cause issues for both live and recording work.

How badly it affects the sound depends on the input, the volume of the input, the frequencies of the input, the room frequencies, etc... In other words too many variables to completely account for without trying. Multiple mics can be used if the pattern of the mic is considered and the null of the mic and the pattern of the mic is taken into the mix (pun intended)

Phil

 

[Sayen]

It's more of an academic curiosity. Due to the nature of the group, the location, and available inventory, two mics is the best shot. One of the client insists on more mics...but they're about a foot apart, and there isn't room to spread them out. Four mics 2" apart isn't going to change anything, and I can't move them closer. The other client insists that 58's don't like to be placed close together, which was a new one for me.

 

[headoned]

Well you dont want the pickup patterns overlapping as like was mentioned before there is more chance of cancelation/phasing due to arrival time difference and the like (i guess you could always phase shift one if your desk is capable?)

 

[JLNorthGA]

I typically use two microphones for Barbershop quartets at about that distance - and they are Shure SM58 microphones. I usually put the toe line at about 2' out. The microphones are arranged in a wide "V". Not necessarily the best microphones or the ones that I would use in a barbershop quartet contest - but they do work reasonably well for shows. If you really want the definitive answer - go to the Barbershop Harmony website and look at their paper on the subject. Documents

 

[FMEng]

More mics would simply sound gastly. In fact, two is too many in the scenario you describe. Here are a couple of references, and Google turns up even more. I can tell you from many years of experience that the 3 to 1 rule works.

THE THREE TO ONE RULE & PHASE CANCELLATION FULLY EXPLAINED

Live Sound: Preventing “Hollow” Sound Through Microphone Techniques - Pro Sound Web

 

[museav]

I'm trying to settle a debate with a client, and Google was not helping me today, nor was Shure's website, although that could be user error. For a small vocal group insisting on using SM58s as a distance - which I already know is not ideal - what happens when additional 58's are added in?

So, say you have a group standing in a 3' by 6' box, 3' from a pair of mics. Obviously not ideal, but bear with me. What happens as you go from say, 2 mics, to four or five?

Are the pair of microphones to try to get a stereo signal? Unless that is the case I might even try it with just one microphone.

Search for "3:1 rule". The mic pattern, aiming, etc, can all factor into each specific situation but to avoid the phase cancellation and combfiltering that Phil noted the general 'rule of thumb' is that you want the distance between microphones to be at least three times the distance from the microphone to the source it is picking up. Thus if a microphone is 3' from the singers you would ideally want 9' or greater between microphones.

Well you dont want the pickup patterns overlapping as like was mentioned before there is more chance of cancelation/phasing due to arrival time difference and the like (i guess you could always phase shift one if your desk is capable?)

I think I know what you were getting at but there would be some challenges. For one thing, the relative phase of the two signals varies with frequency, which is why you get some frequencies that cancel, others that add and most that are somewhere in between. So any 'phase shift' would have to be frequency dependent as any overall change in relative phase, such as adding delay to the channel signal, would shift the frequencies at which the cancellation and summation occur but would not eliminate them. In addition, since each singer has a different physical relationship to the microphones the relative phase relationships between the two microphones can differ for each singer. Finally, the singers probably do not stand still and as they move the physical relationships to the microphones will also change.

However, something as simple as inverting the polarity of one channel could change which frequencies cancel and sum and you could easily see if one condition sounds better (or less worse) than the other.

 

[FMEng]

You could also put more mics on stage without actually using them. Sometimes we sound people have to be psychologists. If doing something makes the musicians happy, and it doesn't degrade the sound quality for the audience or make your life more difficult, then it is a good thing to do.

 

[museav]

You could also put more mics on stage without actually using them. Sometimes we sound people have to be psychologists. If doing something makes the musicians happy, and it doesn't degrade the sound quality for the audience or make your life more difficult, then it is a good thing to do.

Earlier this week I was at the Danley Sound facility for an event and I was talking to someone who does some major concert events in Germany. Because it relates to less to transport and fly, fewer amps, less cabling, simpler setup and so on, they have gone out of their way to put together systems that are very effective for their size. However, they run into event organizers and promoters that 'hear with their eyes' and assume those systems are going to be insufficient without even listening to them. They noted that the hassle that represents is often compensated by watching those people's jaws drop when they then hear the system.

They also mentioned that even after that some still feel that regardless of the sound it produces, the audience expects to see a huge array of speakers and may feel 'cheated' if they don't so we decided there may be a market for giant line array scrims or facades that could be placed in front of the actual systems.

 

[FMEng]

A couple of years ago, I did a live broadcast with a well known jazz musician (from a family of jazz musicians). I selected a good quality studio condenser mic for his sax. He was unhappy with my choice. I offered something with a Neumann badge on it and he was happier. I wasn't the sound he didn't like, it was the brand. Had I stuck to my guns and not changed mics, his performance might have been poor as a result.

I run into professional artists that could care less about how I mic and mix them, and they trust me as a professional. And there are some that want to micromanage every detail, whether they actually know anything, or not. I have learned to smile and go with the flow either way.

I always have to work harder on my people skills than I do on my technical skills, when dealing with musicians. And both contribute to the results.

 

[Sayen]

They also mentioned that even after that some still feel that regardless of the sound it produces, the audience expects to see a huge array of speakers and may feel 'cheated' if they don't so we decided there may be a market for giant line array scrims or facades that could be placed in front of the actual systems.

Absolutely! If you put out extra monitors without plugging them in it's surprising how many performers suddenly perceive a higher volume.