Condenser Mics and Amps

[donkey1]

So, I wish to record using a small diaphragm condenser microphone miking my amplifiers cabinet. I'm not exactly sure which mic I'm getting, but my question is: On average, how loud should I play my amp when recording, I know I can turn it down when it gets into my computer, but I'm just wondering how loud the mic could take before breaking? (Averaging most mic levels)

Thank you.

 

[ez_willis]

On average, how loud should I play my amp when recording

As loud as it takes to sound good.

 

[pohaku]

So, I wish to record using a small diaphragm condenser microphone miking my amplifiers cabinet. I'm not exactly sure which mic I'm getting, but my question is: On average, how loud should I play my amp when recording, I know I can turn it down when it gets into my computer, but I'm just wondering how loud the mic could take before breaking? (Averaging most mic levels)

Thank you.

Personally, I typically prefer a dynamic mic to a condenser for cabs. The usual suspects are the Shure SM-57, Beyer M201, Shure SM7, Sennheiser MD421 and Audix I-5. I'm sure others have favorites as well. Some ribbons also work well for cabs, such as the Royer 121, Beyer M160 and AEA R84. I often use a dynamic and a ribbon together and tweak to taste.

Typically you want to play the amp at the volume that gives you the sound you want. That's why smaller amps are great for recording since you can crank them to get tube saturation and still not have your eardrums bleed and your neighbors want to hurt you. Check the specs for the mic to see what the max SPL rating is to see which mics can take volume. You might also want to see whether the mic has a pad.

Max SPL
As you increase the acoustic sound level into a microphone a point will be reached where the output starts to distort, at first in a minor way and eventually as severe clipping. Most manufacturers list a Max SPL with a THD (Total Harmonic Distortion) figure which links the acoustic input level to a specific amount of distortion. They may choose any level – 0.25%, 0.5% or 1% can often be found. For a typical microphone the relationship between each of these is approximately 6dB so a Max SPL figure of 126dB at 1% THD can be translated with some confidence as 120dB at 0.5% THD. However the reverse may well not apply – a quoted 120dB figure at 0.5% might mean >5% distortion at 121dB if the microphone is on the verge of clipping at this point. An SPL figure with no THD should be assumed to be a level at which gross distortion – clipping – is about to occur. With many microphones (and techniques of measurement) this point will be quite close to the 1% figure but for some designs a large (>10dB) and valuable headroom may exist which will markedly affect the way the microphone can be used.

Here's a site to look up mic specs. Registration is free.

http://www.microphone-data.com/default.asp

 

[Richard Monroe]

I strongly recommend AKG C2000B for that application. I've used it for just that application for years. It can handle up to 155db up close and personal (145db without the pad engaged) which should handle anything short of a Marshall stack set on 10. How loud? 1. As loud as it takes to get the sound you want, and- 2. no louder than the room can take it. Unfortunately, you sometimes reach #2 before you reach #1. If that is the case, you need an isolation cab, a smaller amp, or a better room. Good luck-Richie

 

[ez_willis]

How loud? 1. As loud as it takes to get the sound you want, and- 2. no louder than the room can take it. Unfortunately, you sometimes reach #2 before you reach #1. If that is the case, you need an isolation cab, a smaller amp, or a better room. Good luck-Richie

...or an attenuator.

 

[donkey1]

Hm, okay then. Thanks alot, question answered!

 

[Richard Monroe]

Yo EZ! I'm not clear on your comment. Where would you put this attenuator? You can't put it anywhere in the amp's signal path, because it will destroy the amp's sound, and vastly decrease the amount of air you are pushing. Anywhere later in the signal chain, and you'll just have a quieter recording of the room being overloaded. As far as I understand it, there's no way out of the fact that the amp has to be cranked to do what it does, and if the room can't take it, you are screwed. If we were talking about using modelers with mic'd up speakers, or direct recording, it would be a different story. That's one of my solutions, but not the one the OP is looking for.-Richie

 

[ez_willis]

Yo EZ! I'm not clear on your comment. Where would you put this attenuator? You can't put it anywhere in the amp's signal path, because it will destroy the amp's sound, and vastly decrease the amount of air you are pushing. Anywhere later in the signal chain, and you'll just have a quieter recording of the room being overloaded. As far as I understand it, there's no way out of the fact that the amp has to be cranked to do what it does, and if the room can't take it, you are screwed. If we were talking about using modelers with mic'd up speakers, or direct recording, it would be a different story. That's one of my solutions, but not the one the OP is looking for.-Richie

Your solutions were DEFINITELY the right ones. I was just throwing in one more option if the room couldn't handle the volume. It had nothing to do with the OP's question.

 

[pohaku]

Yo EZ! I'm not clear on your comment. Where would you put this attenuator? You can't put it anywhere in the amp's signal path, because it will destroy the amp's sound, and vastly decrease the amount of air you are pushing. Anywhere later in the signal chain, and you'll just have a quieter recording of the room being overloaded. As far as I understand it, there's no way out of the fact that the amp has to be cranked to do what it does, and if the room can't take it, you are screwed. If we were talking about using modelers with mic'd up speakers, or direct recording, it would be a different story. That's one of my solutions, but not the one the OP is looking for.-Richie

Well, attenuators are definitely compromises. Mine (HotPlate) goes between the amp and the speaker. So I can crank the amp and saturate the power tubes, but you still lose some on pushing air. If you can't run your amp at the volume you want,and you don' have a smaller amp or an iso cab, an attenuator may be an acceptable solution. I have enough small amps that I don't have to do that, but for some that may be a more workable solution.

BTW, I gotta try that AKG C2000B you keep recommending. Now to see what's available on the Bay

 

[darrin_h2000]

cool...I think Ill go and run up the bids on all of them for a goof.

 

[darrin_h2000]

I just bought one for $56 on ebay.

 

[Richard Monroe]

Are you serious, or are you just abusing Pohaku? Actually, it's part of my agenda. If I keep saying it, sooner or later, some frequent poster on this board will shell out for the little bugger, and either back me up, or tell me I'm crazy. I do feel a little like the guy standing on the corner with the sign that says, "THE END IS NEAR!". I still have yet to meet a single honest tracking engineer that actually hates the C2000B after using it. Among it's many other uses, it is simply the best cab mic I've ever used- and I've used a fair number, including the ones that are supposed to rock. The only ones that even came close are Shure SM82 and Sennheiser MD421. Sorry- I'm just not in the SM57 camp. I own one, just for a reference mic, but there isn't a blessed thing I don't have a better mic for.-Richie

 

[darrin_h2000]

Ill be suprised if it wins out over the KSM32...but Ill have more choices...Ill have to sell some stuff to get another mic to fit in the case...Im hoping to score that AT4047 too...then stop buying any more mics.

 

[Shadow_7]

Max SPL is the biggest factor IMO. Too low and you can clip at the mic, before even reaching modest levels on a source. Too high, and you can put the mic almost inside the source and take whatever bad room out of the mix. I love my Avenson STO-2's for micing loud sources in proximity. Micing soft sources from a distance is their weakness.

General rule of thumb. Whatever sounds best. Set your source to the level you like, then find a mic that fits. Attenuation is what you put between the mic and preamp and/or interface if the input levels are too hot. It doesn't compensate for the limits of the mic, it just helps get you a level that your other gear is happy with. Attenuation is basically the opposite of gain.

 

[Richard Monroe]

Well, Darrin, that's a little bit of apples and oranges. KSM32 is twice the price of a C2000B, new or used. Secondly, it is a large diaphragm condenser, and C2000B is a small diaphragm condenser. Although I have no experience w/ KSM32, I have extensive experience with KSM44. If they are similar at all, and I suspect they are, I find the KSM44 to be a pretty transparent mic. I use it, or a C414, when I want to report things as they are. An expensive guitar, a beautiful female vocalist, etc.
What I find different (and useful) about the C2000B is that it is colored without being hyped. In other words, it introduces very subtle distortion, not unlike a tube mic, without boosting or attenuating any particular frequency band. This makes it "flat" without being "transparent". I just hope your mic isn't messed up. At the price you stated, I'd be concerned there was something wrong with it
Anyway, you see the point? I'd put a KSM44 on a vintage Martin, and a C2000B on a $300 Ovation. That color also makes it a great overhead, a great cab mic, and a pretty good vocal mic. And as you have already seen, although the mic was a sonic success, it was a marketing failure, which means that if you spook around, you can find them cheap. I paid less than $100 for each of mine. That would be tough to do with a KSM32.-Richie

 

[darrin_h2000]

Actually the KSM32 is a 3/4 inch capsule...just like the AT3035...Im really thinking of getting rid of the SDCs in my cabinet...the 3/4 inch LDCs have been better in most every situation.

 

[pohaku]

Actually the KSM32 is a 3/4 inch capsule...just like the AT3035...Im really thinking of getting rid of the SDCs in my cabinet...the 3/4 inch LDCs have been better in most every situation.

If you like 3/4" capsules, track down a Groove Tubes GT44 (or the previous version, the Alesis/GT AM-40 - they are the same, just rebranded). 3/4" capsule tube mic. Really wonderful on acoustic instruments. Can be a bargain on e-bay.

 

[darrin_h2000]

Cool Idea...but I might be out of the mic buying game and into the mic selling one...lol....I just bought an AT4047 today.

 

[Richard Monroe]

Thanks for enlightening me Darrin. You might find this FAQ from Shure interesting. They state that the KSM32 does indeed have a .75" diaphragm, and by their working definition, that males it a large diaphragm mic, which may have to do with why I've heard and read it described in that way. If it works, who cares?...


"What does large diaphragm mean?

Some individuals confidently (but arbitrarily) say a large diaphragm must have an inner diameter measuring one inch or more. Although, subjectively speaking, a one-inch diaphragm is relatively large; this benchmark has no basis in acoustical theory or practice. There is a more scientific method that helps give definition to what “large” means. Scientifically, a diaphragm could be considered large if its diameter is as large as the wavelength of the highest frequency it is intended to reproduce. The wavelength of 20kHz is .678 inches under normal atmospheric and temperature conditions. Therefore by definition any diaphragm which measures .678 inches (approx. 11/16” or 17mm) or greater is large.
Does the KSM32 have a large diaphragm?

The KSM32 has a large, .750 inch (3/4”) diaphragm. Shure developed a diaphragm of this size to take advantage of its performance benefits over an even larger sized diaphragm. These include extended high frequency response, improved linearity and more consistent polar response at high frequencies. In addition, Shure’s special embossing process has captured the salient benefit of some larger capsules -- a more highly compliant diaphragm that provides extended low frequency reproduction. By combining a .750” diaphragm with embossing technology, the KSM32 is able to provide rich, smooth lows and balanced reproduction of any source without sacrificing clarity."

Richie

 

[darrin_h2000]

You should write for Shure...that would look beutiful in a brochure.

I think as soon as my new camcorder comes in Ill do a shootout...and post it on Youtube...not enough shootouts online...Ill need a girl with a pretty voice to do this though.