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CM3 - really THAT good? Condenser Microphones
Old 8th December 2016
  #1441
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didier.brest's Avatar
 

Quote:
Originally Posted by Hermetech Mastering View Post
Question, the CM3's impedance is stated at less than 100 ohm, so for the flattest sound should I set my TG2 pres to 300 ohm or 1200 ohm, I am assuming 300 as it's closer?
In general, the highest impedance provides the cleanest sound.
Old 8th December 2016
  #1442
Thanks Didier (loved all your sound clips in this thread too, thank you!), that seems to be the case here, and in general, although not with an SM57, which is probably where I was getting confused!
Old 9th December 2016
  #1443
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boojum's Avatar
Quote:
Originally Posted by Hermetech Mastering View Post

<snip>

I do have a pair of CM3s and the TG2 is a stereo pre, so what I really need to do is tape them together and set one at 300 ohm and the other at 1200 ohm and hit record... When I get around to it I'll post back with my findings after level matching them and having a very close listen (might even post files if I can work out how to do it).
It looks like you will answer your own question through testing. "One test is worth a thousand opinions."
Old 9th December 2016
  #1444
Yes, of course, always best to use your ears and make steps forward based upon your own empirical observations, nothing quite like the scientific method! Just thought it would be nice to "think out loud" in this thread as there are so many knowledgeable people on here with far more mic experience than me. Will try and set up the "impedance test" today.
Old 9th December 2016
  #1445
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mljung's Avatar
Quote:
Originally Posted by Hermetech Mastering View Post
Yes, of course, always best to use your ears and make steps forward based upon your own empirical observations, nothing quite like the scientific method! Just thought it would be nice to "think out loud" in this thread as there are so many knowledgeable people on here with far more mic experience than me. Will try and set up the "impedance test" today.
You may find it interesting (if you're not aware) that Line Audios own preamps has a unusually high input impedance: 10Kohm

::
Mads
Old 9th December 2016
  #1446
Thanks Mads, that is VERY interesting hear!
Old 9th December 2016
  #1447
Here's the impedance test on strummed guitar: 2 x taped CM3s (see pic), 30cm on axis at 14th fret, 45dB of gain from the Chandler TG2 (plus a 54Hz HPF and 70Khz LPF from the Bax EQ). The only difference is one is at 300 ohm mic pre impedance and the other 1200 ohm. I haven't done it blind, it's pretty obvious that 1200 sounds better than 300, and has a more extended high end (see RX5 screen shots). The 300 ohm file was 5.8dB LUFS louder than the 1200 ohm, so I reduced its gain by the same amount for a pretty close level match. It was fun to A/B them on my Crookwood console, I definitely prefer the 1200!

The mp3's are 48Khz, not sure why, as I encoded from 24/96 .wav, so I've also uploaded lossless FLAC versions here, I'll leave them up for a few days:

http://hermetechmastering.com/SoundF...edanceTest.zip

Forgive the poor playing and no fancy finger picking or anything, I am still a beginner guitarist!

[EDIT] For some reason the MP3s files will not attach...
Attached Thumbnails
CM3 - really THAT good?-cm3micstaped.jpg   CM3 - really THAT good?-300ohm-5.8db.jpg   CM3 - really THAT good?-1200ohm.jpg  

Last edited by Hermetech Mastering; 9th December 2016 at 03:21 PM.. Reason: Trying to add more pics...
Old 10th December 2016
  #1448
Quote:
Originally Posted by mljung View Post
You may find it interesting (if you're not aware) that Line Audios own preamps has a unusually high input impedance: 10Kohm

::
Mads
One of the reasons I probably need so much gain on the CM-3s on the X32, it too has an input impedance of 10Kohms.
Old 11th December 2016
  #1449
great news. I lost my pair of CM3s in May, almost tought they were stolen. My wife found them back this weekend
Old 11th December 2016
  #1450
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Bruce Watson's Avatar
 

Quote:
Originally Posted by monitor View Post
great news. I lost my pair of CM3s in May, almost tought they were stolen. My wife found them back this weekend
And Santa's "nice" list just got bumped.
Old 24th December 2016
  #1451
Still loving this mic. if the room isnt great close mic it because it's widepickup will sound a bit washed out if the room is small.....
Old 26th December 2016
  #1452
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jpgerard's Avatar
Hi guys,

Typically, a 5:1 ratio is good practice. We're in impedance bridged systems, not matched. Most dynamic (coil and ribbon) mics having output Z's of around 200Ohms a mic pre should be set to at least 1K. I find 1.2K to be a good minimum. As the pre's Z increases you get a bit less signal but the freq. response increases downwards. In fact the lower input Z settings actually shave off LF (simple capacitive filter). So yes, the higher Z the better and also with condensers. higher Z's also yield improved headroom. Running condensers with low input Z settings can lower their headroom as they run out of juice trying to handle those heavier loads.

Last edited by jpgerard; 4th February 2017 at 06:30 PM..
Old 7th January 2017
  #1453
Gear Head
 

Just ordered a pair of CM3's from JP. Can't wait for them to arrive and start experimenting with them. I guess I should re-read the 1400+ posts in this thread? LOL
Old 7th January 2017
  #1454
Quote:
Originally Posted by improziv View Post
I guess I should re-read the 1400+ posts in this thread? LOL
Nah! Just start using the microphones! : )
Old 7th January 2017
  #1455
I read them all before I got my pair. They sound amazing, best/flattest mic I have heard at that price. I stupidly didn't buy the shockmounts with mine, so am just about to order a Rycote INV 6. I use them for home recording, our apartment building is above a metro station, and I was kind of astounded at just how much sub bass these little fellas pick up through the floor/stand. Am sure the CMEH from LineAudio are great, but I hear the Rycote's are in another league. I emailed Rycote as I couldn't decide between the INV 3 and the INV 6 (both fit the CM3, both same price) and they said basically the INV 6 has greater isolation and can be mounted with more mics and hardware, but is bigger and maybe harder to use when setting up stereo arrays, while the INV 3 is smaller and less versatile with slightly less isolation, but easier for close miced pairs. I really need the isolation so will go with the 6.
Old 7th January 2017
  #1456
I have Rycote shock mounts for my CM3 mic pair. Good stuff. Pricey, but good stuff. I have no regrets in purchasing those.
Old 7th January 2017
  #1457
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Sotsirc's Avatar
I have the rycote too, really good quality shock mounts. And the CM3 is a great quality mic for sure. A bit too realistic sounding for some applications, doesn't color/flatter the source much at all.
Old 7th January 2017
  #1458
Good to know the Rycotes are ace. Yeah, my pair get plugged into a Chandler TG2 pre, so mojo aplenty.
Old 7th January 2017
  #1459
Gear Head
 

Yeah, shock mounts. Need to get some. I found a used/new AT8415 for half price on ebay and will test it. Rycote is a possibility if budget allows
Old 3rd February 2017
  #1460
Gear Maniac
 

Quote:
Originally Posted by Ifrit View Post
That's great, but for me the extra noise is definitely a disadvantage.
Electret vs true condenser. Electret tend to be noisier, don't they?
Old 4th February 2017
  #1461
Quote:
Originally Posted by Geoff Poulton View Post
Electret vs true condenser. Electret tend to be noisier, don't they?
I don't know. Perhaps older ones when the "permanent" charge starts to fail? But I am under the impression that newer materials and better assembly techniques have corrected many of the deficiencies related to electrets?
Old 4th February 2017
  #1462
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boojum's Avatar
Quote:
Originally Posted by Geoff Poulton View Post
Electret vs true condenser. Electret tend to be noisier, don't they?
The DPA 4006 TL was electret, rugged as hell and pretty quiet. Very good sounding mics: https://www.sweetwater.com/store/det...VmfxoCsRvw_wcB
Old 4th February 2017
  #1463
What's the main difference between electret (which I am presuming what the CM3 is?) and "true" condenser? Any good articles out there?

My Rycote INV6 shock came for the CM3 and it's just fantastic.
Old 4th February 2017
  #1464
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boojum's Avatar
Quote:
Originally Posted by Hermetech Mastering View Post
What's the main difference between electret (which I am presuming what the CM3 is?) and "true" condenser? Any good articles out there?

My Rycote INV6 shock came for the CM3 and it's just fantastic.
Google is your friend: True Condenser Vs. Elektret Condenser - What's the Difference?
Old 4th February 2017
  #1465
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jpgerard's Avatar
In broad strokes, Electrets have a permanent charge creating a DC potential between diaphragm and backplate. DC Polarized condenser mics, as the name suggests, use external power sources to charge the diaph. and backplate condenser (capacitor) system which is Phantom power in Solidstate mics or a separate DC rail in tube mics (perhaps split from a HT rail). Modern Electrets can rival their DC polarized brothers in terms of noise, the CM3 achieving just 16dBA. The one advantage I see in DC polarized capsules is that you can take them apart decades later to repair them. Electrets will have to be replaced with a new element at some point but Electrets produced today have a relatively long life expectancy, and even Electrets from the 70's are usually just a couple of dBS down in sensitivity today, assuming you're looking at a decent model like an SM81 or such. One major advantage of an Electret capsule is that it doesn't need external power, resulting in very low total current draw from the microphone (power is required for the head amp but not for polarization of the capsule).
Old 4th February 2017
  #1466
Thanks for the explanation JP!
Old 4th February 2017
  #1467
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jpgerard's Avatar
I should have added in my post that we're discussing SDC capsules and my comments relate to that type of capsule although I guess they also apply to large size components but you really need to go with quite elevated polarization DCV's to achieve single digit noise floors like the latest Rode NT1 etc. which is probably impossible to obtain with Electrets - but I might be wrong, just haven't seen any yet. I'm not aware of many LDC capsules using Electret material... there were admittedly and still are a few out there. I think that at least one of the AKG C3000 variations used a 1" or so Electret capsules and achieved pretty good performance. Audio Technica did OK with Electrets but so far I haven't found a signle one I really liked the sound of (very subjective I know...). Also note that as a designer, you have more freedom working with a DC polarized system as it is easier to change things around, not so much with Electret based capsules. Again, broad strokes, OK... for detailed analysis you can Google the subject and ask on the AKG website forum (assuming it's still there, haven't checked in a while) and their archives as they published a number of very good articles on Electrets and the development thereof at AKG (same thing, not sure if they're still public).
Old 10th February 2017
  #1468
Gear Nut
I finally got to record with my CM3s... here's a student performance of Bach's Gavotte BWV 1006 for solo violin. I used a pair of CM3 in XY (90 degrees), 7' (~ 2.13m) from the violinist and about 55" (1.4m) high. The room is a very live room. This recording has no EQ or reverb added to it. The rest of the chain was a Zoom H6, with the Triton Fethead Phantom.

Perhaps a different mic configuration would have been better, perhaps ORTF or NOS, as the CM3 is, really, a wide cardioid? Any critics are welcome! :-)
Attached Files

BWV 1006 - Gavotte - CM3-XY90.mp3 (6.55 MB, 1061 views)


Last edited by VlaVlnPlayer; 10th February 2017 at 05:21 PM.. Reason: Audio file didn't upload... the .WAV was too large, so I saved in .MP3 to upload here. I'm happy to send the .WAV file to you if you PM me.
Old 10th February 2017
  #1469
Lives for gear
Quote:
Originally Posted by VlaVlnPlayer View Post
I finally got to record with my CM3s... here's a student performance of Bach's Gavotte BWV 1006 for solo violin. I used a pair of CM3 in XY (90 degrees), 7' (~ 2.13m) from the violinist and about 55" (1.4m) high. The room is a very live room. This recording has no EQ or reverb added to it. The rest of the chain was a Zoom H6, with the Triton Fethead Phantom.

Perhaps a different mic configuration would have been better, perhaps ORTF or NOS, as the CM3 is, really, a wide cardioid? Any critics are welcome! :-)
The biggest flaw is probably the room itself....small, live, small, probably even has unpleasant colour of paint upon it...and yes, small ! Nothing particularly amiss with mic choice , placement or signal chain...just the walls themselves.
Old 10th February 2017
  #1470
Gear Nut
The room, itself, is not too small in length, and the colors of the wall are fine ;-) However, it has a low (concrete) ceiling parallel to the floor (overall shape is a rectangular one). I'm glad to know that you don't think that there is nothing amiss with mic choice, placement or signal chain.

Besides treating the room (or using another one), could I have done anything else to improve this recording?

Thanks!
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