MXL 990 - What do you think?

Well if I followed those instructions it wouldn't be much of an experiment imo.

Anyway so I had got this mic free while I was already waiting for another I had ordered. A Sennheiser e815s dynamic mic. Finally got that today, and this also had a pretty low noise floor. I had suspected that it would sound pretty good on my voice and to be honest it kills the 990. While very clean, I now hear more clearly how the 990 lacks character and sounds very sterile and flat.

I'd still use it and have certain uses for it fo sho', but I think the 815 may be my go-to for voiceovers...
 
This mic sits in its case, just in case someone reports that it actually shines on something (Harvey Gerst, above). I know there are some simple mods for it but out-of-the-box---every other condenser (and dynamic) I have outperforms it, and that would include every other even less-expensive MXL mic (V57, V63), Nady SCM800, and the ridiculously low-priced Karma Silver Bullet. Every time I even think of this mic the words "cereal box" get recalled.

Sorry!
Paj
8^|
 
The 990 is the same basic mic (18mm small diameter capsule driving a Schoeps-type circuit) as the Nady SCM-800. The headbaskets are different though and this accounts for some audible difference between them.

The v57 and v63 are large diaphragm K67-type capsules driving a flat response circuit (and thus have the "wrong" frequency response with an 8dB @ 8 kHz peak that is not attenuated by HF de-emphasis as Neumann intended).

The 990 capsule is also found in the MXL 770, Nady SCM-800, MCA-SP1 (well-loved and recommended by Jim Williams once mod'd) and SDC pencil mics like the MXL 603, Nady CM-90, CAD GXL-1200, Apex 180, Avantone CK-1, Mojave Audio MA-100, Mercenary Audio KM-69 etc...The only difference between them all being the different types of capsule front treatment.

Oh, there can be another difference - capsule diaphragm resonant frequency tuning. I've analyzed over 200 of these small capsule diaphragms and found a "bell curve" distribution of resonant tuning frequencies. The upper and lower 10th percentile of diaphragms are about an octave apart in resonant frequency tuning! So when you see widely different reviews of the same mic the reason is probably widely different fundamental frequency tuning of the diaphragms heard by the respective reviewers.
 
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I use the 990 for acoustic guitar recording. I use it with two 603s, with the 990 being placed in front of the sound hole. I have tried a lot of different mic combinations and I haven't been able to beat what I've produced with the 990 and 603s.

Now with that said, I don't think I would actually pay for the mic, I received it free when I bought one of my interfaces, but it has got it's use and if I were to pay the $60 for this mic, I have gotten $60 worth out of it.
 
Mistral said:
*nods and pretends he understands everything MichaelDoly has said this entire thread*
Click to expand...

Oops, sorry about that! Let me de-construct some of that in the form of a glossary of terms I use. Some of this will be obvious to many and new for others. And since this a 990 thread I'll use that mic as a focus...

Headbasket - The shaped wire mesh and frame that surrounds the capsule. Provides AC hum, Radio Frequency Interference (RFI) shielding and some protection from environmental contamination.

There is a direct correlation between shielding efficacy and acoustical transparency. Less wire mesh equals greater open area percentage, less internal reflection and thus faster transient response settling time and a "more-open", less colored sound.

Headbasket shape - There is a correlation between headbasket shape and internal reflection amplitude, settling time and distribution of standing waves vs. frequency. A cylindrical / flat-top headbasket as used in the 990 has more accumulation of internal standing wave coloration than the classic, angled M 49 / U 67 / U 87 shape pioneered by Neumann to reduce headbasket coloration effects.

"Popular SDC Capsule" - I use this term as a catch-all to describe the capsule found in the 990, 770, MCA-SP1, Nady SCM-800 and a host of "MXL 693-like" pencil mics. Outside diameter is about 22mm with an 18mm diameter diaphragm.

Capsule Diaphragm Set-Back - These popular SDC capsules are designed in a such a way that the diaphragm is located some distance away from the front edge of the capsule housing. This "set back" creates a resonant chamber in front of the diaphragm that imparts coloration to the sound pick up. In addition the setback creates some acoustic shadowing and imparts some unevenness to the off-axis response. By contrast, mics like the Neumann KM 184 have the capsule diaphragm located much closer to the front edge of the capsule housing to reduce set-back coloration to a minimum.

Capsule Diaphragm Resonant Tuning - A condenser capsule diaphragm is a piece of thin material (most often Mylar) wth a thin layer of gold applied to create one plate of the "condenser" (capacitor). The gold-coated material is stretched over a mounting ring (most frequency round, there are other shapes) and pulled up to the desired resonant frequency (like a drum head) and secured in place.

K 67-type capsule - Neumann's "second generation" LDC capsule. Designed with an intentional, narrow-band HF peak. Functions as the first stage of a pre-emphasis / de-emphasis system in the U 67 and U 87 mics. This topology offers increased headroom, sibilance reduction and a degree of control over frequency response. The K 67’s peak HF response is centered in the sibilance range then fedback inversely to provide an anti-sibilance response in the U 67 and U 87 mics. The K67 capsule requires the proper HF attenuation to restore proper timbre-balance and not sound excessively bright or sibilant. It is this second stage “anti sibilance” feedback network that is missing in most low-cost K 67-type capsule mics that use a simpler “flat response” circuit.

Flat Response Circuit – The circuit that follows the capsule which provides high-to-low impedance conversion of the capsule’s signal and line-driving capability. The most frequency seen type of circuit in low cost mics is a close approximation of a flat response, transformerless topology pioneered in Schoeps microphones. This circuit was adopted primarily to avoid the cost associated with a high quality output transformer. Unfortunately, the flat frequency response of this highly regarded circuit (clever design, fine sound, excellent transient response) is not the correct match for the HF peaked response of the K 67-type capsule which is often found ahead of the circuit.

K47 Capsule – Neumann’s first generation LDC capsule found in the U 47 and M49 mics. No HF peak, but rather a gentle and broad “presence mound” in the upper midrange. Achieves proper timbre balance with a flat response circuit as used in the U 47.

Ceramic Capacitor – an extremely low cost capacitor frequency seen in the critical capsule-to-FET (or tube) location that provides coupling of the capsule’s audio signal into the FET gate (or tube grid) while blocking the diaphragm polarization voltage from reaching same. Unfortunately, this capacitor type – used in this location, handles the entire low level capsule signal and imparts an edgy, grainy or harsh sound to the audio. Higher quality mics use capacitors with better electrical parameters and thus better sound (Mylar, Polypropylene, Polystyrene, Silver Mica).

Electrolytic Capacitor – often used to provide relatively large capacitance in a small size to pass low frequency audio and block DC. These can introduce cross-over distortion again heard as harshness, edginess or lack of detail.

I think that may cover most of the terms I used in the posts above, please let me know if I missed any.
 
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The statement that ceramic capacitors are not suitable for an audio signal path requires qualification. I refer you to p. 20 of this .pdf of a series of articles by Cyril Bateman (p.14 in that particular article) where the distortion of an X7R ceramic is shown to be rather horrible, but the distortion of a C0G ceramic is not measurable (indeed, exceeding the performance of various poly film capacitors).

So an evaluation of ceramic capacitor type should be made before replacement is indicated.

Capacitor Sound
 
Actually much of what I do these days is engineering custom powering solutions for the European brands; mainly Schoeps but soon AKG & MT Gefell. People will pay quite a lot of money for that sort of thing.

Also, working on self-powered USB interface solutions for the tablet market.
 
DPA does OK with them, and so did your old employer, no? And Shure, and AT--that 35 capsule I'd take over any Chinese K67 imitation, and I think you would too.

Electrets have a lot of advantages--many of them don't need coupling capacitors at all, for example.
 
Well thanks for the efforts into describing those terms for me Michael, I'm sure I'd do well to study up on them when I have more time to do so.
 
COG, C0G. Whatever Mrs. Hilarium, jokester, fool. You're welcome to live up to your pseudonym and come back with the last word - as you always do.

For Christ's sake, step back a moment. You take the time to read through my post, then argue about ceramic capacitor types (which I'm aware of, duh) - really just a CODA in my post intended to clarify terms I'd used that caused some bafflement. Quite a few folks have written thanking me for that glossary and found it helpful.

Btw - re: mic fight club...you're the guy who immediately jumped on my post to focus on ceramic capacitors, take me to task for typing an O and not a 0 and show us how smart you are by citing Bateman. That's how this episode of mic fight club started brother, with you - not me.

DIY'ers can replace the fuckin cheap-ass things with a quality part that costs a couple of dollars (singly) and be done with it.

Oh I know, you get touchy whenever I bag on the $0.90 Chinese electret capsules like those found in millions of telephone answering machines and also your Naiant mics (yes, made by you, Jon O'Neil - why not use a real name in all your online posts? Its like that cat Peter Bloch who re-brands mics as "Stellar" and never provides info about who he is. He is in fact a full time employee of Intel Inc. and never shows his real name in public so as not to endanger his day gig, but rather relies on gear pimps like his homey Kidvybes - another alias for a part time, retired salesman, to pimp his "Stellar" brand stuff), Sahimian etc mics then, shift the conversation.

BTW - I'm the first to admit Earthworks mics suffer from poor S/N ratio - David Blackmer was more interested in transient response than S/N when he started that company.

But to the original poster's question (and I know its an old one, but all hail the longevity of Internet forum threads) - the MXL 990 is probably the most-sold true condenser mic - ever. Far exceeding the superior Oktava MK-012. Who can't afford $60 for a side-address, small diaphragm mic...packaged as a side address large diaphragm mic?

There is actually a lot going for the 990 and its large headbasket when one considers the compromises of putting an SDC capsule in a pencil type body with under-sized vents like the the MXL 603 that peaks the HF response.
 
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Mr. Joly, how come you end up in fights with, well, everybody? I thought you were this mellow, new-age-flute playing, metaphysical kinda guy?

So why attack Bloch? Do you have any evidence he hired kidvybes to pimp? Cause people accused drbill of the same thing with you, and you didn't think that was kosher. So Bloch chooses not to participate in internet fora; that seems to be a healthier state of existence to me :cool:

And sahiaman? What did he ever do to piss you off? He's a nice enough guy from what I can tell, and unlike you or me he manufactures his own capsules, and I don't think they are electret, and he doesn't pimp on fora.

I don't know why you bag on electrets, that is irrational behavior for a man who claims to have personally assembled the first Earthworks mic on his bench. Again, what is wrong with electrets? You say noise? Hmm, the LDC Oktavas as noisy as the SD electret Shure KSM141 (and a couple of mine are within 1dB, and they are only 10mm). The KSM141 matches the noise performance of the externally biased Schoeps MK5, which inspired it. Next objection?

In fact, because of the extremely large market for electrets they are subject to significant R&D, and thus can be expected to continue to exhibit performance improvements over externally biased capsules. The latest greatest from Primo (sadly not $0.90 :() are really, really good, you should try them sometime. You also complain about headbasket effects . . . hey, small pencil-style mics can be almost completely free of them. Score one for SDCs!

And hey . . . I placed with another electret and one externally biased SDC in the top three of my price class in Jasper's shootout, defeating a bunch of externally biased SDCs on the way, including the MK012 and MXL 604. There's some pimpin' for ya :p

Here's a quote from Jasper re: the electret AT4021:

[AT4021] was not only competitive with the 4051, but possibly better and the noise stats were some of the best of any mic in any price class.

(note: listed as 14dBA, but AT is thought by many--for example, re: the AT3032 with nature recordists--to have very conservative noise specs)

$300 or Less

And dude! This is just crazy! The much-derided, very old electret C1000S modded to pull up against the CMC64?!?!

Even More Mics

Moral of the story and real scientific conclusion . . . electret vs. externally biased has no predictive power in suitability for use.

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Anyway, back to capacitors. I somehow doubt you were aware of ceramic capacitor types before I informed you, and I'll be pleasantly surprised if you actually read the entirety of Bateman's seminal articles (hint: another nugget derived from actual scientific measurement--poly bypass caps don't appreciably reduce electrolytic distortion, and so may be merely a DIY placebo; the saw palmetto of the audio world). You fell into the DIY truism of "ceramic=bad". That shouldn't even be a truism; it causes people to tear them out of places in circuits where they really need to be.

Oh, and C0Gs aren't cheap; depending on the value, they are less, the same, or more expensive than the equivalent poly. In values of interest for capsule coupling caps, they are about the same cost, but they can be much smaller which is an obvious advantage in microphone circuit design. They also are mostly insensitive to heat from soldering, which is definitely *not* true of polys. So give 'em a try sometime, you just might find you like them ;)

PS if polys are costing you a couple of dollars, you are buying them from the wrong place. You can get a pretty wide range of Pana polys from Digikey at around $0.40 or less for the values you'd need.
 
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