A good test of small condensers

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rob aylestone

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Ive done lots of mic comparison videos, but when it comes to things like small diaphragm condensers, the differences are always quite small. I just inherited a pair of Neumann 184 mics from a friend’s collection. He bought them just before he passed away. I would like to put them up against a pair of really cheap ones, like Samsons, or maybe a pair of my old vintage AKG 451’s.

Can anyone think of a test that would reveal a bit more of the differences. My video studio has pretty dead acoustics, but I was thinking maybe a grand piano would be a good test, but of course that is in the house, with hard walls? In the studio it would be limited to a guitar I think, because saxes and other stuff is so mic position critical.

Should i be looking for a problem instrument to capture, or a good one people will understand more. I have a feeling that guitars might be a wrong choice, as even cheap mics can do well on a particular guitar, but poorly on another?

I have borrowed these Neumanns a couple of times and they sound nice, but i am struggling a bit to think of a proper, but musical, test. I’m not interested in recording pink noise or technical testing, just my sort of videos where i hope sometimes I put people off wasting their hard earned money, which often happens.

Any suggestions?
 
I think a couple of nylon string guitars and steel string guitars, maybe an entry and "pro" level of each, and played by good players demonstrating different styles, primarily to cover the range and also dynamics of both instruments. Tests with mediocre playing of some strumming (on average or poorly set up guitars) are a waste of time because any mic can capture that.

I'd probably set the mics up in an XY and far enough away that you can have both pairs coincident and arguably rule out differences in placement and performance. Self-noise can be an issue, so a good room is really important, and then, IMO, it's mostly the transient response along with a smooth enough high end and bottom that doesn't fall off too quickly, allowing the track to be used with no tinkering, save what it might need to account for others in the mix. Then you'd be able to report sensitivity differences, while adjusting for it in the audio presented with the video, or for A/B listening.

p.s. You might want to A/B your individual mics in the pairs (pink noise) to confirm they're good for use as a pair!
 
I think a good grand piano track and a good acoustic guitar track would tell me most of what I would need. I agree that self noise is important, especially with SDCs. Most of them seem to have higher noise than the LDCs. It's not intrusive if you do things properly, but if you have to boost the signal, it can start to sneak in.
 
rob aylestone said:
Ive done lots of mic comparison videos, but when it comes to things like small diaphragm condensers, the differences are always quite small. I just inherited a pair of Neumann 184 mics from a friend’s collection. He bought them just before he passed away. I would like to put them up against a pair of really cheap ones, like Samsons, or maybe a pair of my old vintage AKG 451’s.

Can anyone think of a test that would reveal a bit more of the differences. My video studio has pretty dead acoustics, but I was thinking maybe a grand piano would be a good test, but of course that is in the house, with hard walls? In the studio it would be limited to a guitar I think, because saxes and other stuff is so mic position critical.

Should i be looking for a problem instrument to capture, or a good one people will understand more. I have a feeling that guitars might be a wrong choice, as even cheap mics can do well on a particular guitar, but poorly on another?

I have borrowed these Neumanns a couple of times and they sound nice, but i am struggling a bit to think of a proper, but musical, test. I’m not interested in recording pink noise or technical testing, just my sort of videos where i hope sometimes I put people off wasting their hard earned money, which often happens.

Any suggestions?
Click to expand...
Maybe a Banjo and a Violin and Cello - the banjo because it’s nigh impossible to make them sound good with a condenser - the Violin and Cello because it’s hard to capture - but when you hit the sweet spot - it’s fantastic.
 
Violin is often hard because you have to have the mic at a fair distance, at least for good violins playing technical pieces, and the players do not stay still! Then a wider pair can be handy, but takes some "sound-check" time. (Getting a good violinist and violin can also be daunting, depending on where you live and who you know.)
 
Cheers All! Some good ideas here. I usually use LDC mics on cellos, so that could be interesting. We don't have many banjo folk here - in fact, I don't think I have ever recorded one, or had one live on stage? Never thought of that?
 
Attached Rob is my son and that was recorded with a pair of Behringer C2s. He now has a pair of Lewitte 040s and loves them. Higher sensitivity than the C2 and lower noise.
If you can setup multiple types of SDC on classical guitar one of the things players are always after it low pickup of squeaks. My son tells me that a really good technique will keep them at bay but it is very hard! They seek ALL the help they can get.

Dave.
 

Attachments

Piano and maybe drums would be great IMO.
 
What about playing a commercial track through the monitors and recording with each pair and identical placement?
Then you could have the two recordings side by side in the daw and automate some instant flicks between them?

No idea how it would come out but it might be interesting for a wide range of frequencies and it takes differences in the performance/placement out of the equation.
 
Steenamaroo said:
What about playing a commercial track through the monitors and recording with each pair and identical placement?
Then you could have the two recordings side by side in the daw and automate some instant flicks between them?

No idea how it would come out but it might be interesting for a wide range of frequencies and it takes differences in the performance/placement out of the equation.
Click to expand...
It's an Idea yes but speakers do not have anything like the same radiation pattern as any acoustic instrument I know of? (FO that man that said "Theramin"!) and HOW mics pickup the 'field' emanating from a guitar/snare/cymbal/ ??? is one of the most crucial aspects of their performance.

Better I think to have a pair of "control mics" always locked off at a specific distance and orientation then bring in other types, record. Another one or two, di-da?

Dave.
 
Steenamaroo said:
What about playing a commercial track through the monitors and recording with each pair and identical placement?
Then you could have the two recordings side by side in the daw and automate some instant flicks between them?

No idea how it would come out but it might be interesting for a wide range of frequencies and it takes differences in the performance/placement out of the equation.
Click to expand...
ecc83 said:
It's an Idea yes but speakers do not have anything like the same radiation pattern as any acoustic instrument I know of? (FO that man that said "Theramin"!) and HOW mics pickup the 'field' emanating from a guitar/snare/cymbal/ ??? is one of the most crucial aspects of their performance.

Better I think to have a pair of "control mics" always locked off at a specific distance and orientation then bring in other types, record. Another one or two, di-da?

Dave.
Click to expand...
Interestingly, that is exactly how Audio Test Kitchen did their comparisons. They make a recording, then reamped the recordings in an anechoic chamber and using lasers to line up the diaphragms. While the radiation pattern of a speaker might not be the same as a real instrument, it still gives you a good representation of how a mic responds to the frequency spectrum which should be the primary "flavor" of a mic.

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I suppose my idea would come under a technical test more than practical, which Rob did say he wasn't really looking for.
Still, while it might not tell you much about their usefulness for a certain instrument it might, at least, be useful in highlight differences.

If nothing else maybe it could inform your instrument choice for the real test?
 
I am still not happy about speakers as a signal source. The closest thing to that situation is micc'ing up a guitar cab and anyone who has tried that knows the difficulties.
How close, where on the cone, one mic or two? One in the back (shut up that boy!) Even the angle the diaphragm presents to the wavefront* will drastically change the character of the sound.

Then, monitors come with their own self noise, port chuffs and colouration and there is a principle that you cannot judge a "good or bad thing" with a less than pristine source. Your guitar,e.g. might not be THE best guitar in the world but it is at least JUST a guitar!

*Which is very roughly spherical for a small, nearfield monitor up to a few 100Hz. Acoustic instruments on the other hand spew sound out at all kinds of random directions. And you need to be at least 1m away for the woofer and tweeter to 'integrate'. Even further for a larger 3 way.

Dave.
 
I take your points, Dave, and don't disagree but I think we're looking at this thing in two different ways.

If Rob's struggling to hear differences between various SDCs in his previous live instrument recording comparisons,
this could be a good tool, at least, for highlighting differences, especially if he uses source material he's familiar with.

Of course I'd treat the speakers like a live ensemble - Get a good few meters back, if possible.

Not unlike if you're struggling to hear the impact of changing frequency of your 1db boost or cut,
make it a 12db boost or cut and use it like a scanner, then bring the gain back down when you've found what you were looking for.

a 12db boost or cut is rarely musical or useful, but it can be a great tool for sharpening listening skills.
 
Me again! If you have a very quiet studio Rob, one test I would wish you to make is that of a mics self noise.
The vast majority of the people here are noisy bstds! Rock guitar or at least a steel strung. Drums and keyboards, none of which tax the noise performance of even quite poor microphones.

But, folks recording classical guitar or speech* need the quietest mics they can get. Yes, self noise speccs are usually given but a comparison with a known low noise LDC would be interesting to me at least. As a 'pro' studio person Rob no doubt you have a Rode NT1A handy?

*Although LDCs or SM7b etc are more usual for that purpose?

Dave.
 
On the other hand it might suck and be useless, but you don't know until you try. ;)
 
I do have an NT1 - of one type (not sure which) somewhere.
Dave - how would you suggest I do the self-noise thing? I suspect it will be to set a common gain setting on the preamp so that remains a constant and then see how far down the noise floor is, with silence in the room? Maybe I could do this at home, when I try to record the piano. Set up the mics over the piano and record silence, rather than music. The quiescent noise always tickle the digital meters so I wonder what 'silence' might look like in say, Audition?
 
I ponder the thought of a mini-anechoic chamber, aka a microphone "coffin" for self noise sealing up around the cable etc...
wouldn't that do a microphone self-noise test fairly well.?

drill a hole in a aluminum airline mic case , filled with foam or something...it should be fairly quiet, in addition to the preamps noise and all the other electrons moving around.

maybe try a few oxygen free cables too for noise test and various preamps for impedance matching for noise ....ok, Im too tired now.

its like at work, its easy to think up a bunch of tests to do .......and hard to actually physically do them all.
 
Oxygen free cables? That one i rule out before i start. I like the idea of putting the mic into a dead case though. What worries me is that measuring the noise accurately would have to be against an unknown level. If we see on the meters, say, -70dB, i have a feeling that this is uncalibrated. I am never actually convinced 0dB, the maximum possible digital level really is 0dB, because accidental overs often when examined dont actually flat top. The meters go red, but perhaps indicate red for danger when close, to warn. I’ve never tested or proved this, but i suspect it to be the case.
 
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