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Azden FMX-DSLR Audio Mixer Review

Azden FMX-DSLR Audio Mixer Review

Unless you want to go the extra step and record to an extra audio recorder, this is a good buy to solve a DSLR camera's audio issues.

Never underestimate the value of audio. Often times the audio is overlooked on a video shoot, yet depending on your project the audio may convey half of the content or more. The new wave of DSLR cameras has revolutionized shooting video in a lot of ways. Indie filmmakers and amateurs alike are now able to achieve a cinematic look on a relatively affordable budget. These cameras however, lack high-end audio to match. The cameras themselves do not come equipped with adequate microphones, and the cameras are limited in their audio inputs. This leaves you with a couple options; use a small mixer, a mic designed for a DSLR, or a separate audio recording device.

Mic, Mixer, or Recorder

Having a mic specifically designed for a DSLR can be the most affordable; nevertheless it is the most limiting and not always the best quality. Though a separate audio recorder might achieve better audio, it would also require double the button pushing during recording and extra work syncing during editing.

Often times, carrying a mixer around with you on a video shoot is not practical or affordable. Azden's FMX-DSLR mini mixer solves that issue. This handy little mixer mounts directly to the bottom of the camera and to the tripod head at the same time, acting as an in-between device to your camera-tripod setup. This is a natural location for the mixer. While there are few mounting options, at least the form of your camera is still capable of being handheld operated. There is a nice professional build to the device and it seems solid, however the specific design of the FMX-DSLR is slightly quirky since it is slightly longer on the front side, causing it to protrude out from beneath the lens of most cameras.

The Mixer

The mixer itself has two XLR inputs, with volume control for each. XLR inputs are a big plus and leave your options open for lapel mics or condenser mics of your choice. Ultimately, the most professional mics will make used of the XLR inputs, and you are resisting the addition of adapters to your video setup. The mixer has an 1/8-inch headphone jack and audio monitoring is easy enough on the FMX-DSLR. One drawback to be aware of, is that most DSLR cameras do not have an audio out for you to hear what the camera is recording. Playback of the video clip becomes necessary to be sure the audio recorded properly, which would become a big issue at live events such as weddings where you only get one take.

When monitoring your audio, there are no audio level meters on the FMX-DSLR mixer. That is tough. Since you can only hear what the mixer is hearing, not what the camera is recording and without levels it becomes fairly difficult to adjust the audio properly. You'll be relying on your attention to audio to get it just right, In addition, Nikon and Canon cameras have an AGC (Auto Gain Control) causing the camera to automatically readjust your incoming audio. By default, there is no way to disable the AGC on most Canon or Nikon DSLR cameras; meaning unless you install a third party firmware, you are limited to auto controls on all your audio despite the fact that the mixer has volume controls.

AGC

Not only do most DSLRs default to AGC, but the Azden FMX-DSLR mixer also has an AGC switch. Azden claims the AGC creates "noiseless operation." In our test, the AGC produced a loud high pitch noise during recording, making the recorded clips unusable. When the AGC was switched off the mixer preformed well and delivered good audio with fairly little noise. Switching off the AGC is a trick! The switch is hidden on the bottom, opposite of the volume dials. Unless you take the mixer off the tripod and search the mixer, the switch is easy to overlook. While the recessed switch allows for flush mounting, the AGC can only be switched on or off with the camera detached.

In the Field

In our field test, the Azden FMX-DSLR mixer preformed rather well. The battery life was substantial. Azden claims a 15-hour run time on four AA batteries. In our test the mixer lasted more than 15 hours of interviews and four hours of live event performances, a welcome surpassing expectation. A nice touch is that the AA batteries are very easy to switch out; so often do small electronics tuck away batteries seemingly forever - the FMX-DSLR slides out a carriage for all four batteries with open borders to easily handle both sides of the battery. For a video interview with a decent pro lapel mic, we were able to get good clear audio with little noise. We discovered that in order to get a condenser mic to work you must switch the appropriate channel (L or R) DC48V to "on" and these two crucial switches are found near the AGC switch.

All in all, the Azden FMX-DSLR mixer performs well. The mixer is small and compact and fits right under the camera. The mixer comes with a coiled 1/8-inch cable, and there is no extra mounting gear needed to make this mixer work and you can utilize it handheld or on a tripod. The battery life surpassed the manufacturer's claim. The overall audio quality is good. It's priced affordably and looks professional.

Tech Specs

Frequency Response
Main and Unbalanced Output: 20-20,000Hz (+0/-1dB)
Monitor Output: 50-20,000Hz (-1dB)

Noise Level
Left & Right Channel: -110dB
T.H.D.: less than 0.01% @ 1 KHk

Inputs
Line/Aux Low setting: Max Input Level +22dBu Max Gain -22dB
Line/Aux Hi setting: Max Input Level +6dBu Max Gain -6dB
MIC1/MIC2 Low setting: Max Input Level 0dBu Max Gain 0dB
MIC1/MIC2 Hi setting: Max Input Level -16dBu Max Gain +16dB

Output
1/8" (3.5mm) Stereo: -3.5dBu (32 ohm load)
Maximum Output Level (unbalanced): (3.5mm) +0dBu (2K ohms)
Battery Type/Life: AA (4) Alkaline 15+ hours with phantom power off
Current Drain: 40mA nominal (Phantom Power Off) 80mA maximum (Phantom Power On)
Phantom Power Voltage: 48VDC (+/- 2VDC)
Size (HxWxD): (1.75" x 4.2" x 4.2") (44x105x105mm)
Weight w/o Batteries: 16.6oz. (470 grams)

Strengths

  • XLR inputs
  • Volume control knobs
  • Long battery life

Weaknesses

  • Slightly larger than a DSLR camera base
  • Limited by camera's audio quality and AGC

Summary

This is the perfect camera for the shooters on the go that love to show off what they did in the moment.

Azden Corporation
www.azdencorp.com
Price: $400

Luke Scherba is a video producer and production studio owner.

Tags:  September 2012
Luke
Scherba
Sat, 09/01/2012 - 12:00am

Comments

lmenningen's picture

Notice you don't have to mount the mixer under/at the camera. The output of the mixer is a mic-level signal which means you can plug it directly into a wireless transmitter, and put the wireless receiver (which is smaller and lighter) on the camera. Doing so yields a side benefit: you can then have several cameras, each with a matching receiver, thereby feeding identical sound to each camera.
lmenningen's picture

Actually I do this with the Azden FMX-42 mixer which has separate left and right outputs, so I can feed them into two transmitters - I use Azden's 330 dual receivers mounted on four cameras. Therefore, to get 2-channel audio to multiple cameras with this unit, you'd have to make an 1/8" splitter and plug its legs into separate L and R transmitters. You can use mono audio, just use one leg of that same splitter with one transmitter, and then use a mono receiver. the mono receiver feeds its mono signal to both left and right camera channels.
Bruce McIntosh's picture

This looks like a fairly good means to improve the sound recorded with DSLR cameras but I would recommend strongly considering the Zoom H4n currently for sale at Amazon for ~$250. It has two XLR inputs with optional phantom power and a pair of unique and quite good stereo microphones. The latter can be switched out to give two more external mic channels. You also get 4 separate VU meter channels. Because of the 24bit dynamic range you don't have to be too fussy about levels and you can balance the channels in editing. At first the synchronization was a pain but when I got the PluralEyes software that problem went away. One issue not fully addressed in the article is that no matter how good the mixed feed to a Canon (T2i in my case) the AGC will destroy the audio quality. Having the audio on a separate device solves this.
steve4505's picture

No audio meters is not good unless you have Magic Lantern or the newer cameras with the meters on the viewfinder. There are several similar products, Beachtech has been out for a while. Sound Devices makes a mid level professional one. Both Fostex and Juicedlink just released theirs too. I personally don't like the Zoom H4n because there is no gain on the XLR's. Therefore the noise floor is quite apparent. The H4n continues to have problems with its battery compartment cover (which generally ends up being taped on). I am looking forward to a new generation of the H4n because its a 3 year old product. PluralEyes is far from perfect. I recommend doing some solid research before purchasing or in many cases you may have been able to purchase a much better product for $200 more. AGC is good but for instance the new update on the 7d eliminated the need for AGC.
steve4505's picture

Oh found a new review on the Juicedlink RM333. Remember there is another model RA333 which has meters. https://vimeo.com/47364773. There is a comparison link to the Juicedlink site with an audio comparison to the H4n. I may be incorrect on the gain on the H4n.