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CM3 - really THAT good? Condenser Microphones
Old 30th January 2015
  #1111
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voltronic's Avatar
 

Hmm, lots of views and no comments leads me to believe you all are being polite. I'm certainly open to constructive criticism.

This didn't quite sound as I expected. I like the dynamics but the imaging is somewhat disappointing. In retrospect I wish I had gone for a slightly narrower spacing to create a wider SRA, but I had only about 5 minutes to set up and no time to really adjust, and only my DIY fixed NOS mount allowed me to angle downward. This was also my first instrumental ensemble recording from this mic perspective, though I've had success with choirs in the past with the same placement.

The director also had a Schoeps m/s array and a pair of AKG 214 feeding a Zoom H6 farther out in the hall, and my recording was intended to give a close perspective contrast to possibly mix with either of those sources or be used alone. I unfortunately don't have access to that recording for comparison.
Old 30th January 2015
  #1112
RPC
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Quote:
Originally Posted by voltronic View Post
Hmm, lots of views and no comments leads me to believe you all are being polite.
Well, the first thing I thought was "This is why I don't like mp3!" It's actually quite a good recording. If you want me to pick it apart I'd say that the lack of bass in the CM3s shows, especially on the bass drum. I also expected more reverb given the perspective you've chosen - is the hall very dry or is this a byproduct of your chosen mike position?
Old 30th January 2015
  #1113
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Quote:
Originally Posted by RPC View Post
Well, the first thing I thought was "This is why I don't like mp3!" It's actually quite a good recording. If you want me to pick it apart I'd say that the lack of bass in the CM3s shows, especially on the bass drum. I also expected more reverb given the perspective you've chosen - is the hall very dry or is this a byproduct of your chosen mike position?
Well if you prefer, here are the WAVs:
https://www.dropbox.com/s/tdl3xmylfv...ake03.wav?dl=0
https://www.dropbox.com/s/earjbmg51x...ake02.wav?dl=0

Regarding the reverb, it's a fairly large hall but it has a carpeted floor so decay time is short, not much more than 1 second. I wouldn't call it a dry room though. When I've recorded there before, I've been midway out in the hall and gotten much more ambiance as one would expect.

Looking back at it, I think adding a pair of spaced omnis would have gotten me closer to the sound I was looking for.
Old 30th January 2015
  #1114
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Very interesting. When I listened to the MP3 files, I thought, "wow, it sounds like they were recorded in a small, (acoustically) dead closet.
It wasn't just the lack of "room" acoustics, but I thought I heard some very close reflections as if the players were in a room no bigger than the band seating arrangement.
I am listening on my new JBL SR305 speakers which I like a lot.
But then when I listened to the uncompressed WAV file (data compression, of course, not signal level compression!) the closed-in "boxy" sound was gone. IMHO

Of course, this is more a comment on MP3 vs WAV than it is about voltronic's recording technique, however. But I found it fascinating.
There are several controllable parameters one can select when doing MP3 compression, and I believe one of them is combining the common L+R information. I wonder if that is what I am hearing?

But as for the recording itself, yes I agree that it seemed a bit "dry" and "clinical".
Of course, one could argue (and I have) that it is better to have a "clean and dry" signal to which you can add the desired reverb, than the alternative.
And the low end seemed thin. Which is why I was interested in the version of the CM3 WITHOUT the built-in LF rolloff.
OTOH, maybe over-hyped commercial recordings with artificial "diddling" of the LF instruments has biased our expectations?

Thanks for sharing, and for going to the extra effort of letting us hear the MP3 vs. WAV.
Old 30th January 2015
  #1115
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Thanks for your comments. The stage is very large with quite extensive wings and fly space, but there was a wall of portable tone shells directly behind the percussion section. They would have been about 30ft or so from my stand.

I never considered the effects of mp3 encoding combining common L+R information. I now actually hear a significant difference between playing the mp3 directly on my computer versus playing it from the GS integrated player in my post which sounds much more congested. I cannot get nearly as high a level using that player as I can when playing the local files in my computer. I use foobar with the SoX minimum phase resampler, although I'm not sure how much benefit if any that brings to mp3 files. The mp3s were encoded using LAME at 320kbps.

I would also be interested the proposed CM3 without the LF rolloff, although I wonder if the tradeoff will be increased proximity effect making them less useful for close applications.
Old 31st January 2015
  #1116
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Richard Crowley's Avatar
 

Quote:
Originally Posted by voltronic View Post
I would also be interested the proposed CM3 without the LF rolloff, although I wonder if the tradeoff will be increased proximity effect making them less useful for close applications.
And I believe the problem with proximity effect for close applications is exactly why he offers only the rolled-off version. Adding a switch to control the roll-off would add considerably to the cost of making those things. It was likely a good economic decision to go for the larger market.
Old 31st January 2015
  #1117
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Quote:
Originally Posted by Richard Crowley View Post
And I believe the problem with proximity effect for close applications is exactly why he offers only the rolled-off version. Adding a switch to control the roll-off would add considerably to the cost of making those things. It was likely a good economic decision to go for the larger market.
The roll off is just the physics of the capsule isn't it? Anyone can create a more linear version with some EQ.
Old 31st January 2015
  #1118
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Quote:
Originally Posted by jpgerard View Post
Don't forget that the CM3 has a built in (non defeatable) low cut. It helps compensate for proximity effect. Now, if there were enough requests, I could, maybe, order a small batch of special CM3's with a linear low end down to, say, 50Hz, shifting the -3 dBs point to somewhere around 30Hz. Personally I prefer a tiny bit of EQ in post if required, as the CM3 works most of the time as it is... but if a flatter sub-100hz response really helped some users when distant mic'ing, I could talk to Roger about it. Thoughts?
Old 1st February 2015
  #1119
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Perhaps he is wrong. The low end graph looks like most other (Neumann, Schoeps, etc.) single small diaphragm capsules of the same directivity
Old 1st February 2015
  #1120
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Looks like this thread needs some more information! I'm not wrong, and I never talked about an electronic or physical low cut. The response of the CM3 is the sum of various parameters and I apologise if I used "low cut" and gave the impression that the CM3 has an electronic filter in its head amp. The CM3 is designed, like most cardioids, to give a response that is flat at close range, with a subtle roll off to compensate for proximity effect. There is physical (capsule and body) and electronic trickery used to obtan the desired response. Here's a cut and paste from my discussion with Roger about it:
"In order to get the directivity and flatness, the bass it already lifted by a few dBs. I am not sure about raising it further. It should be about 3dB down at 70Hz, 6dB down at 50Hz (@1m). Pretty easy to compensate for afterwards. It would be possible to change some component values inside the mic, but, hm. Another model. I have to think about that one."
Which means maybe someday or if there's enough demand, maybe a small batch, but that's a lot of maybes. Personally, I think that low end management is best done with a smooth, transparent EQ in post production. All the "notes" are there, for the musically inclined, it's just a matter of spectral balance. I never had a customer complain about a "lack of bass" from the CM3, but it's true that like most cardioids, it rolls off (and again, please note that this is a result of the overall design, it's not just a capacitive filter in the head amp) the low end a touch. A cardioid without this feature would result in a bump in the very low to low mids at less than 1m from the source, getting worse as you get closer, like any directional design will, which is a problem in most cases. Using Omnis, which can, when designed properly, reach down below any AD converter's LF cut off, will give you not only a totally flat low end, but also freedom from proximity effect so it won't matter how close/distant the mic is located vs. the source. So to sum it up, if you like the CM3 but somtimes would like a slightly more elevatd low end, don't hesitate to use a touch of EQ (a couple dBs boost with a clean, shelving EQ in the sub 200 Hz are should do) or try the OM1 (but obvously being Omnidirectional, you'll have to live with more room sound in your recorded signal, which shouldn't be a problem if you placed the mics at the optimum distance and the room happens to sound good). I hope this helps!
Old 1st February 2015
  #1121
I got a pair of cm3's yesterday and omg they are good, for this price unbelievably good, I've only tried it on classical guitar through so far, looking forward to trying them out on steel string, percussion and other things. This is first time I've ever thought the recording sounds exactly how it sounded in the room...will post audio clips soon
Old 1st February 2015
  #1122
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voltronic's Avatar
 

Thank you, JP for that great info. I might experiment with some EQ in post as you suggest. I don't understand the complaints about lack of bass with the CM3 in general. To me, they just sound like cardiods, in that I don't expect full low end extension. I'm not sure what cardiods out there don't roll off at a distance. As you say, if you need flat low bass you can use omnis.
Old 1st February 2015
  #1123
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jpgerard's Avatar
Yes - and the only cardioid that was sort of ruler flat down under 100Hz was the KM84, as well as earlier Schoeps (CMT54 Series I think?). But most cardioids always have a bit of roll off. The problem when you think about it, since there's proximity effect, is at what distance from the source should a given cardioid mic yield a flat response? The only way round the problem is a mic with a ruler flat response down to 20Hz and a variable HPF, maybe labelled with distance in feet or cm. rather than in dBs of drop at a given frequency... on the other hand, cardioids have been around for decades and engineers have learned to work with them. Not perfect, but acceptable all things considered.
Old 2nd February 2015
  #1124
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Quote:
Originally Posted by jpgerard View Post
Looks like this thread needs some more information! I'm not wrong, and I never talked about an electronic or physical low cut. The response of the CM3 is the sum of various parameters and I apologise if I used "low cut" and gave the impression that the CM3 has an electronic filter in its head amp. !
Without going into chapter and verse, you did give the impression that there was a high pass filter in the mic, and this mis-impression was not corrected as it was continually repeated in the thread.

The fact is that the mic has no high pass filter.

Nothing, though, to do with the very good microphones and your well earned reputation for consistently excellent service.

Last edited by JEGG; 2nd February 2015 at 01:24 AM..
Old 2nd February 2015
  #1125
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Quote:
Originally Posted by jpgerard View Post
Yes - and the only cardioid that was sort of ruler flat down under 100Hz was the KM84, as well as earlier Schoeps (CMT54 Series I think?). But most cardioids always have a bit of roll off. The problem when you think about it, since there's proximity effect, is at what distance from the source should a given cardioid mic yield a flat response? The only way round the problem is a mic with a ruler flat response down to 20Hz and a variable HPF, maybe labelled with distance in feet or cm. rather than in dBs of drop at a given frequency... on the other hand, cardioids have been around for decades and engineers have learned to work with them. Not perfect, but acceptable all things considered.
Including the importance - or not - of off axis consistency.
Old 2nd February 2015
  #1126
RPC
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Proximity Effect

The distance at which a gradient microphone has a flat bass response is an "artistic" decision on the part of its designer. From the frequency plot of the CM3 it's pretty obvious the design distance is 30cm/1ft. By way of contrast an SM81 (KSM137/141 is similar) is designed to be flat at 1m/3ft, with the first click on the bass rolloff switch making the appropriate compensation for 30cm. In both cases the responses for both distances are plotted so it's pretty straightforward to approximate the EQ elsewhere in the chain.
It's up to the designers to let us know how they designed the bass response; it's up to us to either use the mikes the way they were designed or to know how to compensate for using them differently.
(CM3 response here; SM81 response here.)
Old 2nd February 2015
  #1127
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Ribbons rule's Avatar
Quote:
Originally Posted by Douglas Whates View Post
Rather than start a new thread, just thought I'd post here.

Very, very happy with the CM3 pair I ordered. Absolutely incredible. Of course, the longevity and durability remains to be seen, but in terms of sonics... wow!

Listen to a piano and bass recording here:



Just the one pair, completely dry, no EQ.
Could you please repost that piano and bass recording ( or others) you made with the Audio Line CM3 mic? Still have and use them? What do you think about them now? ( I am thinking of buying a pair).
Thanks
Old 2nd February 2015
  #1128
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Smile #2 is musical

Quote:
Originally Posted by vasikgreif View Post
Ok, here go the examples, with photos with mic placement. No editing done, except of slight panning... Sorry for sloppy playing...

What's your prefferred one, and would you have any other ideas on mic placement and making the sound better (the piano needs get tuned for sure.)

#2 is musical...and gets some of the room also! Thanks Vasikgreif.
Old 3rd February 2015
  #1129
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With the positive reception that the CM3 and OM1 have received, does Roger have any plans to offer any higher end model mics or is he sticking solely to the CM3 and OM1?
Old 3rd February 2015
  #1130
here are some audio clips I recorded last night, this is just my classical guitar and the cm3 pair of mics, in ORTF, AB then XY played 3 times, from the same position using a k&m stereo bar. I used my Audient iD22 using the onboard preamps and AD converter, no post processing of any kind except fades and overall volume matching within wavelab so they are exactly the same LUFS to create the least bias possible. enjoy!
Attached Files

Lagrima_mic_comparison_mix1.mp3 (3.44 MB, 2055 views)

Old 3rd February 2015
  #1131
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Quote:
Originally Posted by 2manyrocks View Post
With the positive reception that the CM3 and OM1 have received, does Roger have any plans to offer any higher end model mics or is he sticking solely to the CM3 and OM1?
Is it the price or something about the performance that you find problematic?
Old 3rd February 2015
  #1132
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I don't find anything problematic as I own four CM3s and am keeping them.

My question is whether a higher end model might be forthcoming that would represent as good a value as the CM3 so I don't spend $$$$.$$ for a main pair of Schoeps, Gefell or Sennheisers.

Does that make sense?
Old 4th February 2015
  #1133
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Quote:
Originally Posted by pencilextremist View Post
here are some audio clips I recorded last night, this is just my classical guitar and the cm3 pair of mics, in ORTF, AB then XY played 3 times, from the same position using a k&m stereo bar. I used my Audient iD22 using the onboard preamps and AD converter, no post processing of any kind except fades and overall volume matching within wavelab so they are exactly the same LUFS to create the least bias possible. enjoy!
Very nice. I think all three sounded nice with the 2nd clip being my favorite. As a fellow classical guitarist I would like to know which pattern was which along with mic distance and room type.
Old 4th February 2015
  #1134
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Quote:
Originally Posted by 2manyrocks View Post
I don't find anything problematic as I own four CM3s and am keeping them.

My question is whether a higher end model might be forthcoming that would represent as good a value as the CM3 so I don't spend $$$$.$$ for a main pair of Schoeps, Gefell or Sennheisers.

Does that make sense?
I just wonder what you are missing, what you want in that "higher end" version that is lacking for you in the current models.
Old 4th February 2015
  #1135
Quote:
Originally Posted by Given To Fly View Post
Very nice. I think all three sounded nice with the 2nd clip being my favorite. As a fellow classical guitarist I would like to know which pattern was which along with mic distance and room type.
firstly thanks for listening and commenting!

the mic distance was around 1.5 feet away at a 45 degree angle pointing down mic 1 towards the neck/body join and mic 2 towards the 9th fret, the mics were spaced around 17-18 cm from each other on the stereo bar, apart from XY where they overlapped.

part 1 is ORTF, part 2 is AB spaced pair and part 3 XY, the room is quite dry sounding with lots of bass traps and QRD skyline diffusers, room size is around 12x10 with 10 foot ceilings, not really ideal but it's all I've got.
Old 5th February 2015
  #1136
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Quote:
Originally Posted by pencilextremist View Post
firstly thanks for listening and commenting!

the mic distance was around 1.5 feet away at a 45 degree angle pointing down mic 1 towards the neck/body join and mic 2 towards the 9th fret, the mics were spaced around 17-18 cm from each other on the stereo bar, apart from XY where they overlapped.

part 1 is ORTF, part 2 is AB spaced pair and part 3 XY, the room is quite dry sounding with lots of bass traps and QRD skyline diffusers, room size is around 12x10 with 10 foot ceilings, not really ideal but it's all I've got.
Ideal or not, it was nice to hear the contrast of the stereo patterns on another classical guitar.
Old 5th February 2015
  #1137
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Quote:
Originally Posted by pencilextremist View Post
firstly thanks for listening and commenting!

the mic distance was around 1.5 feet away at a 45 degree angle pointing down mic 1 towards the neck/body join and mic 2 towards the 9th fret, the mics were spaced around 17-18 cm from each other on the stereo bar, apart from XY where they overlapped.

part 1 is ORTF, part 2 is AB spaced pair and part 3 XY, the room is quite dry sounding with lots of bass traps and QRD skyline diffusers, room size is around 12x10 with 10 foot ceilings, not really ideal but it's all I've got.
THank you for the useful guitar sound samples and details about your setup and room. I just acquired a pair of CM3's myself and will be doing some recording tests with my steel-string guitar, to see how it compares with your experience. I look forward to making nice recordings with these microphones, about which I've heard such good things on this long thread.
Regards.
Old 5th February 2015
  #1138
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jpgerard's Avatar
Quote:
With the positive reception that the CM3 and OM1 have received, does Roger have any plans to offer any higher end model mics or is he sticking solely to the CM3 and OM1?
No, no immediate plan to re-release the higher end models like the SM6i and such. He has no time to do it, and he can't even keep up with the current CM3/OM1 demand. But back to the now discontinued SM3/SM6 etc, he even told me he wanted to improve the capsule design although the results were already really, really good. He's really aiming high, I don't blame him. And yes, he is working on new ideas which will eventually turn into new products. But I wouldn't hold my breath and they won't replace the CM3 and/or OM1. i'll make sure there's a New Product alert when something new comes out.
Old 5th February 2015
  #1139
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Thanks as always for your informative posts.
Old 5th February 2015
  #1140
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Line Audio fig 8

What would really be nice, JP, is a good symmetrical figure 8. Beat Sennheiser to the punch! How long has everyone been waiting for the mkh8030?
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