Earthworks TC30K on the kick

[twonky]

Hiya!

Has anyone ever tried the Earthworks tc30k on a kickdrum and does it sound good?

Will it harm the mic to have pressure that high on it? I want to put it about 2-3 inches in front of the hole in the front head.

My questions will get more dummer, just be patient.

jerks! (just kidding) (not really)


Twonky

[littledog]

The reasons why the tc30k is not commonly used as a kick drum mic are:

1) it is omni directional, so it will not reject other parts of the kit as much as a cardioid

2) for the same reason, you can't use proximity effect to add to the sound

3) many classic kick mics have a presence peak at certain frequnecies that have become a part of the historical way a recorded kick drum is expected to sound. sSince the TC30k is "flat", the sound will be different than one might expect.

That being said, no reason why you shouldn't try it. Perhaps using the Tunnell technique (a blanket over a chair or mic stand or sawhorse) that Harvey described elsewhere (with the mic a couple of feet away from the drum) might be an interesting application.

[Wil Davis]

The TC30K is rated at 151dB, whereas the Shure Beta 52 has a max SPL rating of 174dB. I've used my TC30Ks as overheads, or (mostly) as spaced-omnis - in both applications I've found them to work really well. I'm sure the TC30K will work great on a kick-drum, but like most condenser mics, they are quite fragile compared to a dynamic like the Beta 52. I think I'd be afraid of the drummer getting too carried away...

- Wil

[littledog]

Condensers ARE more fragile than dynamics in the following ways:

•they don't like being dropped
•they don't like being hit with drumsticks
•they don't particularly care for high humidity
•they don't like being used to hammer nails

That being said, it is my feeling high SPL's might cause some distortion, but probably pose no particular threat to the mic capsule itself. The amount of sound pressure it would take to actually knock the diaphragm back into the charged plate would have to be enormous (jet engine? nuclear bomb?). That being said, the inside of a kick drum would probably be one of the SAFER places in the studio to put a condenser mic.

I would like to hear if any of the real engineers (Knightfly/Barefoot/Harvey, etc.) out there agree or disagree. After all, everyone knows by now I have the technical engineering knowledge of an average tree stump. (Please respond to this if you have real knowledge - not just repeating popular misconceptions!)

[Track Rat]

Extremely high SPL can stretch the diaphram. That being said, I've used AT-4033's and GT AM-52 on kicks with success ( usually in conjunction with a dynamic like a D-112). I have a pair of SR-71's (cardiod) and I don't think they'd be worth a damn on a kick but I have used them under a snare with OK results.

[hokypokynose]

Right now I have a double kick drum setup in my studio, with an se electronics se1000 on the drummer's right(the kick he most frequents), and an AT3035 using the 10db pad on the left. The drummer doesn't have holes in the front heads, so I just put the mics right up close almost kissing the heads. Sounds quite nice when I pan the two about 9:00 and 3:00. So far I havn't noticed any deterioration of the mics and they sound as good as ever.

[twonky]

I like the Beta 52 inside, I usually do that, but of late I have been yearning for a less...inside the drum w/ a Beta 52 kinda sound.

Like, I want the Albini kick sound. I hate to say that because the Albini kick sound probably come from some stupid cool Eastern Bloc mic w/ Albini doing the recording on a Studer. But you know what I am getting at. Mixed w/ that Albini sound, I want a more atmospheric kick sound ala Talk Talk's Laughing Stock or The Flaming Lips' Soft Bulletin.


Those are the albums of which I fucking love the ways the drums sound. My drummer has a really nice premier kit w/ a great kick so the drum is very versitile.

[littledog]

Originally posted by Track Rat
Extremely high SPL can stretch the diaphram.

Good! This is the kind of info we need to seperate fact from fiction. Now, can anyone verify if this is actually a problem in practise? (I hadn't heard this one before, but that, in itself, means nothing.) How about it, tech guys?

[c7sus]

I've stretched a few large diaphragms in my time.

But not with high SPL!

[Track Rat]

Originally posted by c7sus
I've stretched a few large diaphragms in my time.

But not with high SPL!

"Oh Baby, take off your ring, you're hurting me."
"That's not a ring, it's my watch."

[Son of Mixerman]

How high of SPL are we talking about? P/A gives you load distribution over the effected area. You would need the density of the diaphragm to calculate how much of the diaphragm can take before it stretches. Does anyone know how gold sputtering effects the mechanical properties of mylar? Anyhow, Im pretty sure the the increased density of the gold sputtering and the surface tension of the atypical mylar diaphragm means the diaphragm will tear before it hits the plates. The hard parts is that the mechanical properties of plastics and rubber are quirky to say the least. I believe the distortion happens because of pressure differentials creating turbulance inside the capsule, preventing it from capturing the incoming pressure changes. I assume if everything works the way its suppose to... We could break the sound barrier, but the buffeting at .89 mach goes away post transonically in most cases. Ooops Sorry guys, Sometimes my work bleeds into my lunch time bbs-ing... Heh heh

SoMm

[twonky]

Dirtbags!

I think, it will be ok to stick the TC30K in front of the kick. I will go out on a limb and say that. I really dont know anything, but you guys should trust me.

[Wil Davis]

I'll go out on a limb and say that I agree with you. I really don't know anything either, but just don't do it with mine - OK?

- Wil

[knightfly]

Wellll, here's a bunch more hooey to add to the chaos - Since a SPL of 160 dB is capable of perforating a human ear drum instantly, and 180 dB is about what you'd get standing at ground zero of a space shuttle launch, let's assume that we're not going to record anything louder than 180 dB. I've seen idiots put their heads inside my folded horn mains at an outdoor concert and walk away without blood dripping from their ears, so it's probably safe to assume that there was less than 160 dB SPL present - more like 120. (They're still idiots...)

Anyway, 160 dB SPL is equal to 2,000 Pascals, or 2 kPa. 180 dB is equal to 20,000 Pa or 20 kPa. To get pounds per square inch from kPa, we divide by 6.894 757 - so, 20 kPa pressure is equal to 20/6.894 757, or approximately 2.9 psi. Since a LD condenser mic has about a 1" diaphragm, it presents a surface to the sound pressure that is only 0.78539815 sq. inches, which means that the entire diaphragm would be subjected to no more than 2.277654635 pounds of pressure. (NOT psi ) This would be the pressure at 180 dB - 160 dB would be 1/10 of that, or 0.227765463 pounds. Converted to ounces, would give 3.644247408 ounces of pressure on the whole diaphragm at 160 dB.

160 dB may be able to perforate a human eardrum, but the numbers don't suggest to me that a mylar diaphragm would be as unlucky - however, in the case of the mic, we're talking stretch, not perforation.

The numbers above are accurate to the best of my knowledge, however the conclusions are just as confused as everybody else. Maybe we could all chip in and buy one of those cheapie Chinese LD condensers and chart the response at 80 dB, fire a .44 magnum beside it at 1" away, and then retest it? If one of those can take it, a Neumann should be ok... Steve

[h kuhn]

I have used a earthworks sro on kick and it sounded ok (the sro should sound very similar to the tc30k). I sticked it into the drum as far as possible, but i had to gate it and put a high cut @ 2khz if i remeber right (bleed from snare and high hat). It dpends alot on the sound you are looking for, in a jazz setting it might work well, but i wouldn't use it for rock.

[Son of Mixerman]

Originally posted by knightfly


Converted to ounces, would give 3.644247408 ounces of pressure on the whole diaphragm at 160 dB.

Ok Steve, next math question for you, is what it the deflecton delta of a 6 micron gold sputtered 1" diaphragm at 3.65 ounces?

The eardrum is easier to damage because there isn't really any structure, human cells are what? Water mixed with a little flesh or something.

SoMm

[knightfly]

Good question, SoMm - that's why my own contusions lean toward "so fuckin' what?" I would think that mylar, even 1 mil like tape backing, would be tougher than that. Although, as I stated somewhere in the last book, I have no empirical data on that. Besides, that 3 ounces or so is for the entire area of the diaphragm, so would be considerably less at the center. Anybody wanna start a collection for that cheap chinese LD condenser? I already have the .44 mag and a shooting range, just not willing to toast one of my LD condensers for an experiment the results of which I don't ever plan to need. Plus, my RS sound level meter would puke if I shot the .44 near it, so I wouldn't have a reference SPL other than "240 grain hollow point, x grains of unique powder, CCI magnum primer, etc" :=)

Good question, tho - do you already have the answer and just like to tease, or what? Steve

PS - "human cells are what? Water mixed with a little flesh or something." I think it's the "something" that can cause the problems - I meet 'way too many people in which that "something" between the ears needs to be wiped and flushed... :=))

[Son of Mixerman]

Originally posted by knightfly

Good question, tho - do you already have the answer and just like to tease, or what?

I could get the answer, but Im not going to spend the time to disassemble any of my LD condensors to measure the distance from the diaphragm to the plate. I would have to figure out which mylar is used and see if there are any published properties. Then I would need dimensional data on the holes where the screws go through the mylar for clamping and hole elongation under tension, poissons ratio and all that jazz. Then after all that I can build a nice pretty FEM in CATIA and export it into Nastran, but of coarse Id need to sacrifice a few test models to correlate the results, and then validate the results through a peer group. The fastest way is to have a cmm measure the deflection from neutral to plate contact, have the resistance measured at the probe head with a pressure gage. I was hoping that Stephan Paul, Harvey Gerst or someone would already have this info off the top of their heads. Its basic things needed in capsule design right?

SoMm

[Harvey Gerst]

It ain't the SPL of the kick that you hafta worry about - it's the friggin' air blast coming out of that hole in the front head. That air motion will bottom out the diaphragm.

Just as when you pop a mic by singing "P"s and "B"s, it's not that you're singing loudly, it's the puff of air that's coming out that causes the problem.

If you can blow out a match at whatever placement you choose, that probably isn't a good place to put a ribbon or condenser mic. Keep the mic out of that air stream and you'll be pretty safe.

[twonky]

Thanks Harvey, thats really all I wanted to know.

I also wanted to know if it sounded cool.

We'll see.




Twonky

[Son of Mixerman]

Originally posted by Harvey Gerst
It ain't the SPL of the kick that you hafta worry about - it's the friggin' air blast coming out of that hole in the front head. That air motion will bottom out the diaphragm.

Thats funny, how the air blast coming out of that hole in front of the head, also goes for people ((the hole in front of your head)).

Ok, so lets get really side tracked now.

How do plosives, pops, and ess size correlate to SPL?

Does the SPL rating really matter for musical applications?

Will wearing womens panties on your head work better than a pop filter?

Why do the wire mesh on condensor mics have to be so thick?

Why don't manufactures make the screens so they rotate to provide an adjustable plosive protection built in?


SoMm

[Harvey Gerst]

Originally posted by Son of Mixerman

Thats funny, how the air blast coming out of that hole in front of the head, also goes for people ((the hole in front of your head)).

Ok, so lets get really side tracked now.

How do plosives, pops, and ess size correlate to SPL?

They don't; plosives and pops are air movement, not sound pressure levels. You're mic is mistaking that huge air blast as a note and trying to handle it as an SPL level which is far in excess of its capabilities. Get rid of the air blast, and the SPL is well within the usual limits. It's like trying to sing outdoors in a strong wind.

Does the SPL rating really matter for musical applications?

Not too much. Ribbons are pretty much the exception; the lower the note, the less SPL it can handle, and of course, ribbon mics are very susceptable to wind damage all the time.

Will wearing womens panties on your head work better than a pop filter?

IT might be good for a gimmick, but some distance between the mic, the pop filter, and your voice is usually best. Also, there is a space of about 1/2" between the two circles of pantyhose on a standard pop filter; that space helps diffuse the air blast even more.

Why do the wire mesh on condensor mics have to be so thick?

It's done to prevent damage to the grille from things hitting it, like drumsticks, guitar headstocks, and Roger Daltry.

Why don't manufactures make the screens so they rotate to provide an adjustable plosive protection built in?

People would forget what position they were using, it would destroy the high frequency response, and it would add to the cost of the mic. A separate filter is still gonna work better than a built-in pop filter.

SoMm

[Harvey Gerst]

How weird. My replies on this thread aren't showing up on the forum index.

[knightfly]

They're showing up for us to read, Harvey, and that's all that really matters. Since you're here, what happens to a condenser mic when the diaphragm hits the backing plate? Is it now toast, or does it have to collide with more force to actually damage the diaphragm in some way? Yeah, I know it ain't really SPL, but it's still pressure, so how much can a typical diaphragm take before she gets pregnant?

Also, I looked around Neumann's site the other day when this destructo talk started, and found nothing in the way of generic theory of operation or physical layouts on Condenser mics - Do you know of a link for such info?

Having dealt with LLAARRGGEE diaphragm condenser "mics" (scientific instrumentation)whose HIGHEST frequency was sub-audible, I think I may have jumped to some wrong conclusions about how the capacitance change is converted to voltage in an audio range transducer. Some stuff to read on that subject would be really appreciated as well.

Thanks for any more insight you may have... Steve

[knownuttin]

Honestly, wearing women's panties on your head was thoroughly covered in the big mic thread. When is it going to made into a sticky and permanently installed in the main menu so we don't have to keep bumping it?
-kent