MXL 9000

Like the MXL 960 and the Stellar CM-3 microphones reviewed below, the MXL 9000 is a tube condenser microphone that requires a dedicated, external power supply in order to operate. According to MXL, the 9000 uses a 12AT7, a miniature dual triode vacuum tube. I was unable to confirm this visually as the only marking on the tube is “MXL.” The 12AT7 is in the same tube family as the 12AX7; however, the 12AT7 has slightly less gain. My understanding is that the lower gain of the 12AT7 yields a signal that isn’t quite as hot, thus providing a “cleaner” signal.

My tests confirm that this microphone does indeed produce a very clean sound when used on acoustic instruments. Proximity effect is noticeable, but not quite as prominent as the Stellar CM-3 reviewed below (the CM-3 really shouldn’t be used as a vocal mic anyway). I did notice a very slight “eshiness” with the MXL 9000, but it wasn’t objectionable. In fact, this microphone seems to have a fairly smooth overall response. The MXL 9000 possesses a “warm” quality that seems typical of tube condenser microphones.

As with the MXL 960, the MXL 9000 presents a good platform for modification. The microphone is easily disassembled to facilitate tube substitutions, capsule replacement and other circuitry modifications. With that being said, I found the MXL 9000 to be a very good microphone in its stock form.

TNC Audio ACM-4

The TNC Audio ACM-4 ribbon microphone sports a short, dual-ribbon design and is a rebadged ShuaiYin SYR50. It’s exactly the same mic as the Apex 215 and the Alctron HRM-14B.

Ribbon microphones have a very low signal output and the dual-ribbon design of this microphone helps boost its output and sensitivity. When I compared the ACM-4 side-by-side with the ACM-1 and the NADY RSM-4, the ACM-4 definitely produced a noticeably higher output than the others. It also had a slightly brighter response in the upper frequencies; however, it was in no way “edgy” or harsh. In fact, the ACM-4 seemed to have the most balanced frequency response of all the ribbon mics I’ve tested so far. I would still prefer to use the ACM-1 long ribbon mic for baritone sax and low brass; however, if I were going to record flute or piccolo, the ACM-4 would be my choice.

I must admit to a bit of a bias toward ribbon microphones for horns, particularly trumpets. A good ribbon mic can take the brassy edge off a loud, screaming trumpet section in a jazz ensemble and give it just the right timbre in the mix.

TNC Audio ACM-1

This is a TNC Audio ACM-1 ribbon microphone. It has a “long ribbon, short path” ribbon motor design and is manufactured by Shanghai ShuaiYin of China.  It's one of many similar ribbon microphones rebadged for different distributors in the United States. This microphone is essentially the same mic as the NADY RSM-2 and the Alctron HRM-1. ShuaiYin’s version is branded the SYR-14 and is identical to the TNC Audio ACM-1 pictured here.

This microphone sounds amazing on horns, especially trumpets and French horns. It’s reminiscent of the RCA 77DX ribbon mic I used in college. It also sounds terrific on baritone sax.

Although the ACM-1 already sounds great in its stock form, the cool thing about this particular microphone is that it’s an excellent platform for modification. Just replacing the stock transformer with one of higher quality will allegedly yield excellent results. That, plus removing the extra windscreen shielding from the headbasket and adding sound absorbing material inside the microphone base can result in a quality of sound that rivals other ribbon microphones costing 10 times as much.

NADY CM100

The NADY CM100 is marketed as a “measurement microphone” (e.g., calibrating loudspeakers in a particular room space, as well as for tweaking sound system EQ). The NADY CM100 is also sold by Behringer as the ECM8000 and by Audix as the TR-40. They’re all essentially the same microphone.

The CM100 is not really intended for use as a studio recording mic; however, it has an extremely wide and flat frequency response, high definition and an omnidirectional polar pattern that made it very tempting to try as a field recording mic. I must say, I was rather pleasantly surprised at the results. I used it to record a small jazz band and the CM100 showed a very even, uncolored character – with a couple of caveats.

First, the polar pattern of the CM100 is not linear across its entire frequency spectrum. I noticed that the upper harmonics of the off-axis instruments were rather subdued. Second, on very pianissimo passages the microphone’s self (white) noise becomes apparent. On louder sources and passages, this isn’t as much of an issue.

NADY RSM-4 Ribbon Microphone

This is a NADY RSM-4 ribbon microphone. This is an excellent microphone for its price (typical street price is around $80.00 USD). This mic is of the “short ribbon, long path” variety (referring to the configuration of the ribbon motor - click here for an excellent article by Michael Joly explaining the different types of ribbon microphones). The NADY RSM-4 appears identical to the SYR30 microphone manufactured by Shanhai ShuaiYin Electronics Ltd. Alctron has a similar model, the HRM-15.

Ribbon microphones are relatively simple, passive devices. A ribbon mic operates by suspending a very thin corrugated ribbon between two strong magnets. Sound waves vibrate the ribbon, which generates a tiny current. This tiny current is then sent through a built-in output/matching transformer. Ribbon microphones also require a lot of gain compared to other types of microphones, so a good preamp is a must.

Because of their relative simplicity, Chinese ribbon microphones are very popular platforms for modification, usually involving little more that upgrading the transformer and removing any extra layers of mesh in the headbasket and/or around the ribbon motor itself.

Because the ribbons are so thin (frequently 2 microns or less), ribbon microphones are extremely fragile and even the slightest breeze can destroy the ribbon. Because of this, ribbon microphones are simply not suited for live, on-stage sound reinforcement use. Ribbon mics were used extensively in the motion picture and broadcasting industry for decades and can still be seen sitting on the desks of many television talk show hosts like Larry King.

The NADY RSM-4 microphone has a very warm, robust character which is typical of ribbon microphones in general. This microphone sounds excellent on trombone and would also be near the top of my list for trumpet as well. It doesn’t have quite the transient response or top end I would like for violin or viola, but I would definitely consider it for string bass. This mic would also work well with tenor and (especially) baritone sax.

Although the NADY RSM-4 is rated to handle very high SPL’s, I would be very selective about what type of sound sources I would put near this microphone. Certainly, any source that generates a large movement of air would be out of the question, for example in front of a bass (or “kick”) drum.

Cascade VX20

Like the MXL 992 below, the Cascade VX20 has a 10db pad for high SPL sources, plus a low-cut switch to reduce proximity effect with close-in vocalists. The Cascade VX20 also comes with a shock mount of respectable quality.

The sonic characteristics of the Cascade VX20 are interestingly similar to the MXL 992; however, I notice ever-so-slightly less definition in the midrange frequencies with the Cascade mic. This is a very subtle difference and I would consider it a matter of personal taste as to which of the two microphones I would prefer for a particular acoustic instrument.

Given a choice between the two microphones, I might be inclined to choose the Cascade VX20 over the MXL 992 if I were called upon to record a harpsichord (for example). I feel the Cascade mic would give me good transient response and a clean sound, but not so much “edge” as to over-emphasize the plucking of the strings. I feel this microphone would also work well on banjo or steel string acoustic guitar.

MXL 992

This is the MXL 992. It’s a fairly large microphone, although not as large as the MXL 960 shown below. Nonetheless, I would suggest it be mounted on a secure stand with a low center of gravity. The 992 comes supplied with a shock mount, which will also work with the MXL 990; however, the shock mount that comes with the 990 shouldn’t be used with the 992, as the width of the band on the 990 shock mount is not wide enough to properly secure the 992. It also comes with a nice case for transporting and storing the mic.

The MXL 992 comes with 10db pad for handling instruments with high SPL’s and a low-cut switch to mitigate proximity effect on close-in vocals.

The 992 has sonic qualities that are similar to the 990, but with a more robust bottom end. This may be due, in part, to the larger capsule of the 992. Overall, I like this microphone and would not hesitate to use it for any application where I would use the MXL 990. Plus, I would be more inclined to use this mic on horns such as tenor or baritone sax than the MXL 990.

The MXL 992 also seems to have a respectable level of transient response, so I would consider using this microphone on piano, although it might not be my first choice for strings. I feel the MXL 603S is more suited for this purpose.

Update 1/17/2010: Like the MXL 603’s I tested two MXL 992’s with the same 1898-vintage Sohmer upright piano. The only difference I noticed is that the 992 sounds more robust in the bass register. Plus, I noticed a slight emphasis in the midrange frequencies as compared to the 603’s. Because of the more robust lower frequency response, I might be more inclined to use the 992’s on a concert grand piano. I would classify this preference as only a matter of personal taste as both the 603 and 992 sound very good on piano in general.