C12 Style Mics for Orchestras & Choirs?

[myferalprofessor]

I'm interested in getting into recording some academic orchestral and choral performances. In my mic collection I have a pair of Earthworks QTC40 microphones that I know would be solid for this application, but I have been drooling over a pair of Advanced Audio CM12 mics for a while now. The CM12s would overall be more useful for my day-to-day audio work, particularly with the selectable polar patterns but I'd have to sell the Earthworks to make room.

I'm wondering whether using spaced stereo C12 style mics in omni mode is a decent choice for choirs and orchestras. When I worked in the studio we used our pair of vintage C24 mics as go-to mics for small choirs in the live room all the time. But that's quite different than using them in large halls.

Is using C12s for classical just crazy talk or a reasonable alternative?

Thanks!

[pasarski]

From the technical stand point C12 may not have required bottom end for orchestral recordings. AA CM12 has a different circuit so it might work. Though I'm under impression that SDC's are more favored by engineers nowadays for classical work.

[myferalprofessor]

Hmmmm. The AA CM12 is spec'd down to 15 hz, and the lowest response of the AA tube line and only 5hz higher than a DPA 4006A.

The AKG C12VR is only spec'd to 30hz. Not sure about the response of the originals...

It appears the AA mics do have slightly extended low-end. Indeed, the low-end response may have contributed to the choice of the C24 pair over the C12 for choirs where I used to work, as they have extended low-end response in comparison.

So based on specs, the response of the AA mics seems adequate for classical work. As you said, small diaphragms are the standards these days but since the Earthworks have just sold I'll just have to give the CM12 a try and see how it sounds!

[Salty James]

"specs"?

I would use km84's or manley refc's.

[myferalprofessor]

Originally Posted by Salty James

"specs"?

I would use km84's or manley refc's.

Found this thread that probably has a lot of relevant information:

AKG C414 on orchestral recordings? (+ general usage)

[Matti]

Use omni mics if you want the lows -C12 in omni?

Matti

[RKrizman]

Originally Posted by pasarski

I'm under impression that SDC's are more favored by engineers nowadays for classical work.

How unfortunate.

-R

[myferalprofessor]

Originally Posted by RKrizman

How unfortunate.

-R

Indeed. I've heard some great recordings done with LDCs.

[BHickey]

I use to assist from time to time for a guy who would record the Nashville Symphony and Orchestra. On one date where a large choir was lined up behind the orchestra, he put his C24 up about 10 feet in front of the choir, and it sounded amazing (btw, he recorded the rest o the orchestra with four DPA small diaphragms, sorry don't remember which ones exactly).

On the overall LDC vs SDC, I've used 414 and other LDCs on orchestral and choral work which sounded great. Very lush and full. SDCs are probably more "accurate" but that doesn't mean that they sound better all the time!

[pasarski]

Originally Posted by RKrizman

How unfortunate.

-R

Unfortunate that SDC's are favored over LDC's or unfortunate that I'm under that impression?

[RMJAZZ]

I think the best results are when you use a combination of the two. I also think that you might want a different flavor of sound for different applications. Being familiar with the sound personality of both types of mics is one of the basic skills an engineer needs to have.

With that said, I usually am a fan of starting with LDC's for my main mics (stereo pair/decca etc...). I also usually prefer LDC's on bass and cello as spot mics. For the rest of the spot mics I go to sdc's first, and compliment with ribbons when things start to get too harsh as is the case with most trumpets! LOL

Would you paint a picture with all one color????? How boring.

not a sermon, just a thought.

Rob

[myferalprofessor]

Originally Posted by RMJAZZ

With that said, I usually am a fan of starting with LDC's for my main mics (stereo pair/decca etc...). I also usually prefer LDC's on bass and cello as spot mics. For the rest of the spot mics I go to sdc's first, and compliment with ribbons when things start to get too harsh as is the case with most trumpets! LOL

Would you paint a picture with all one color????? How boring.

not a sermon, just a thought.

Rob

Certainly agree there. Yeah, I do quite love ribbons in general, but after using my AEA 92 as my primary mic I've been craving some sizzle. It'd be neat to get a second 92 someday. Nothing compresses like stereo ribbon room mics do. Ever try an RCA BK-5 in a classical situation? Seems like being a directional ribbon it would be an ideal spot mic for a cranky instrument.

[BHickey]

On the LDC vs SDC argument, as I had stated earlier, I wouldn't say one is right or the other. I will say that one of the most commonly used mic for orchestral recordings is the Nuemann M50 or M150, both being large diaphragms.

But, when recording from very far away (as is often done for live orchestral recordings since mics are not to be seen and also need to pickup the performance hall as well) small diaphragms do tend to shine as they are on average more sensitive to lower levels, and have faster transient responses allowing for more detail from further distances.

That being said, if you are operating from closer distances (15 feet or closer), then LDCs work just fine and pick your mic based off of your personal tastes of what sounds better.

[didier.brest]

Originally Posted by BHickey

On the LDC vs SDC argument, as I had stated earlier, I wouldn't say one is right or the other. I will say that one of the most commonly used mic for orchestral recordings is the Nuemann M50 or M150, both being large diaphragms.

tutt
M50,TLM50 and M150 have a small diaphragm mounted on a sphere. One can get a similar response from Neumann omni SDCs by means of a diffraction sphere, especially from the KM133D that has the same titanium cap like the TLM50 and M150.

[JP__]

Originally Posted by BHickey

Nuemann M50 or M150, both being large diaphragms.

You´re wrong. Both are SDCs.
Georg Neumann GmbH - Products/Current Microphones/M 150 Tube/Description

ooops, to late...

[sonare]

Mics that really do sound like C12s are usually considered too bright in the digital age-- but everyone has their own tastes. The classic recordings that used 47s and 49s (and the CBS favorite C12) were definitely in a different age when considering the capture and delivery medium.

Today most live recordings do not suffer from the "thinking" that mics should be heard and not seen. When I did a "live/session" CD of the Houston Sym for Naxos we had 24 mics (and stands) on stage. The funniest thing was that someone thought the 10ft stand with the mains behind the podium would be less "obtrusive" if the stand were draped in black. It ended up looking like the wicked witch of the north after "melting" down.

Rich

[JonesH]

Originally Posted by sonare

It ended up looking like the wicked witch of the north after "melting" down.

Great

[BHickey]

Originally Posted by didier.brest

tutt
M50,TLM50 and M150 have a small diaphragm mounted on a sphere. One can get a similar response from Neumann omni SDCs by means of a diffraction sphere, especially from the KM133D that has the same titanium cap like the TLM50 and M150.

You are absolutely right. I don't know why I wrote it like that. No more multi-tasking while posting on GS, you guys don't miss a thing!

The point I tried to make was that from further away, small diaphragms often work better (much how a decca tree of M50s are often used to pick up the whole orchestra) because their increased sensitivities and transient responses give more clarity. However, at closer ranges, especially for spot and solo mics, some might opt for a mic that has a favorable tone, be it small diaphragm or large. When I met Shawn Murphy, he told how he often uses ribbons and vintage LDCs as many spot mics with his modified M50 decca tree covering the entire orchestra.

So will the C12s work? Yes, definitely on spots or choirs which could use more body and less transient response. However, if they are the only two mics to pick up an entire orchestra from a distance, maybe not (but then again, given the right placement in the right room with the right musicians, who knows).

Thanks didier.brest and JP for keeping me honest!

[fifthcircle]

There may be a lot of folks that say you can only use SDC for orchestral work, but IMO, that is a load of crap. For me, diaphragm size has no influence on the mic that I choose for a given job. Some say that only SDC work off axis and that's the reason why you need to use them. In my experiences, there are plenty of LDC that sound just as good off-axis as on. None of them are modern Chinese-made, but there are enough.

I've recorded orchestras with U47's, UM57's, U67's, U87's, SM69, C426, C422 and plenty of other mics. The modern AKG C12VR is actually a pretty amazing orchestral mic. It's kind of a pain to use on site because of power supplies, but it sounds fantastic for classical music. Of course it sounds nothing like an original C12 which is not a favorite of mine for classical (too bright for non-diffuse field settings)

To go back to the original subject- I don't know the C12 clone you mention, but the big problem with most of them is they go beyond the original mic's brightness. The original C12 is bright, but not in the modern way- almost a "sheen" on the sound. It really is something special in the right situation. Of course, the other issue with using original C12 (and C24 for that matter) on classical work these days is capsule matching. The age makes it really difficult to have two capsules that sound the same which is obviously an issue with stereo techniques.

--Ben

[Audiop]

Originally Posted by BHickey

small diaphragms do tend to shine as they are on average more sensitive to lower levels, and have faster transient responses allowing for more detail from further distances.

The point I tried to make was that from further away, small diaphragms often work better (much how a decca tree of M50s are often used to pick up the whole orchestra) because their increased sensitivities and transient responses give more clarity.

A small mic has lower sensitivity than a large mic if we talk about surface area of mic membrane and everything else is equal.

I also doubt that small mic's would be more sensitive to low levels. If so they would actually be compressors and that can easily be investigated by performing a simple distortion measurement. If a device has such a nonlinearity that it is more sensitive at low levels it will have high levels of HD and IMD.

Most decent SDC have very low distortion, like -80dB (0.01%) down or less at medium levels and not until 130-140dB SPL they reach 0.5-1%THD.

The explanation for your perceived differences is likely the frequency response on and off axis which tend to be different. Transient response follows frequency response.


/Peter

[didier.brest]

Originally Posted by Audiop

Transient response follows frequency response.

Is it that simple ?
Neither the frequency response nor the harmonic and intermodulation distortion can represent possible non-linear effects on transients. Note also that even for a perfect linear microphone, the frequency response as given in the specifications (which is a smoothed version of the actual measurement) does not determine entirely the transient response, which is also depends on the phase. That's why DPA (like some preamplifier builders) provide the phase vs. frequency response of some of their microphones.

[Audiop]

Transient response depends on phase and frequency response. Phase follows frequency response in minimum phase (MP) systems.

The impulse response of a MP system tells you everything about transient response, phase response and frequency response.

Feed a square wave thru a wide band amp and look at the "perfect" output on a scope. Put some analog EQ on the square and look how the square changes on the output.

You can look at the scope - not doing any analyzing at all - and tell a lot about the phase + frequency response.

People claim and argue a lot of things without understanding this, which is a waste of time. Not thinking on anyone specific, just a general trend on the net.

Originally Posted by didier.brest

Is it that simple ?

Yes I think so. I've been looking for something that indicates the opposite on and off for years without success.

Neither the frequency response nor the harmonic and intermodulation distortion can represent possible non-linear effects on transients.

If you have nonlinear effects on transients (as in nonlinear transfer curve looking at amplitude) you also have it on sines and any other type of signal, and the other way around.

You still can have distortion in the time domain without seing spectral distortion though. Analog filters have phase distortion but cause no spectral distortion or amplitude compression.

Note also that even for a perfect linear microphone, the frequency response as given in the specifications (which is a smoothed version of the actual measurement)

Smoothed or not depends on who and how.

does not determine entirely the transient response, which is also depends on the phase. That's why DPA (like some preamplifier builders) provide the phase vs. frequency response of some of their microphones.

As mentioned, phase and frequency response are tied to eachother in min-phase systems. I don't think DPA claim something else.


/Peter

[didier.brest]

The relation between phase and frequency response is a pure mathematical relation that was never shown (AFAIK) to be useful in a real world application because
1) it is true only for exact linear systems while no real world system is exactly linear,
2) an infinite precision about the amplitude vs. frequency is needed for deriving the phase vs. frequency,
3) it is an integral relation involving the whole frequency response up to infinite frequency.

Any experimented sound engineer knows that judging a mic only from its frequency response and distortion figures is full BS.

[Audiop]

Originally Posted by didier.brest

The relation between phase and frequency response is a pure mathematical relation that was never shown (AFAIK) to be useful in a real world application

Are you serious?

because
1) it is true only for exact linear systems while no real world system is exactly linear,

High quality audio gear is very very linear so that's really no problem in practice.

2) an infinite precision about the amplitude vs. frequency is needed for deriving the phase vs. frequency,

Are you saying that modern measurement gear lack resolving capacity in this regard?

Any experimented sound engineer knows that judging a mic only from its frequency response and distortion figures is full BS.

That's an opinion which you of course are entitled to.

On and off axis frequency response, distortion (nonlinear and linear) and noise is what it's all about according to all we know.

I know there's a lot of people claiming there are more to it, I remain sceptic until someone bring some substance to the table.

Beliefs and gut feelings is something I value less than science and fact when it comes to audio engineering.

Please show me a real world example of a device assumed being MP actually being non-MP. I sincerely want to learn about it if I have missed something.

Also please show the practical significance of the deviation as it relates to audible thresholds and just noticeable differences.


/Peter

[didier.brest]

Originally Posted by Audiop

On and off axis frequency response, distortion (nonlinear and linear) and noise is what it's all about according to all we know.

The beginning of the wisdom is knowing that we know nearly nothing.

[Audiop]

Originally Posted by didier.brest

The beginning of the wisdom is knowing that we know nearly nothing.

The beginning of wisdom is knowing the difference between knowing and believing.

Of course there are lots of things that humanity lacks understanding and knowledge about. I think it's safe to say audio and and audibility is not one of these things.

When you say:

The relation between phase and frequency response is a pure mathematical relation that was never shown (AFAIK) to be useful in a real world application because

You basically say that the whole world is wrong and you have a level of understanding that no one else or few has/have. Extraordinary claims demands extraordinary evidence.. :-)


/Peter

[didier.brest]

I already told you why this relation, mathematically true under some conditions, could not be used in the real world. Especially it requires the knowledge of the spectrum up to infinite frequency. You might object that we are interested only in audio signals that are bounded spectrum signals. Which is untrue because any bounded spectrum signal is an analytical function; and any analytical function is fully determined by its value on an interval as small as you want. So if the audio signal was analytical, any sound engineer could record only 1 microsecond of a performance (assuming that his recorder has infinite accuracy) and get back home for computing the remaining of the performance. Terrific perspective that would change much the audio business...

Hence any real world signal cannot be frequency limited. Another more direct evidence comes from the fact that any frequency limited signal has infinite duration according to a mathematical property of the Fourier transform.

As a consequence, you relation involving an integral on the whole spectrum is useless. Just mathematical masturbation. Have fun!

Could you provide us with the phase vs. frequency response of a Neumann TLM50, the amplitude frequency response is given by the attached graph. How many degrees deviation between 20 Hz and 20 kHz ?

[John Willett]

Originally Posted by didier.brest

Could you provide us with the phase vs. frequency response of a Neumann TLM50, the frequency response is given by the attached graph. How many degrees deviation between 20 Hz and 20 kHz ?

I have never seen phase response curves for any mics. except in the original brochures for the Sennheiser MKH 20/30/40 series.

Sent from my iPhone using Gearslutz

[joelpatterson]

Originally Posted by sonare

... like the wicked witch of the north after "melting" down...

That would most likely have been the Wicked Witch of the West.

See? I can be as pedantic as any of you!

[didier.brest]

Originally Posted by John Willett

I have never seen phase response curves for any mics. except in the original brochures for the Sennheiser MKH 20/30/40 series.

You had never seen.