I recently bought an ART ProMIX from Musicians Friend to use a low cost field mixer, pre amp, and phantom power adapter. The regular price is $79.99, but since they were out of stock I opted for a $59.99 refurb unit.

I was attracted to the ART Pro MIX because its inexpensive, it offers phantom power from batteries, offers headphone monitoring, and mixes three balanced inputs into one balanced output. What I hoped would be an adequate interim solution until I can source a more expensive and purpose designed piece turned into a disappointment. Before I return it, I would be interested to know if anyone else is using this with positive results.

Previously I have been using an M-Audio Audio Buddy as a mic pre and phantom power supply with a XL1 to quite good sounding results. The Audio Buddy is sold as a computer input accessory and has the single problem of not operating on batteries. The Audio Buddy is powered with a 9v AC wall wart. I think the Audio Buddy requires AC power in order to accomplish the voltage multiplying required for the phantom power circuit, but since I am not an electronics this is pure speculation. Whatever the reasons, the Audio Buddy will not work from DC battery power (I’ve tired it) and I don’t want to have the preamp be the only thing tying me to shore power.

The Pro Mix looks like it might work, but after connecting it to a condenser mic and some headphones I uncovered its many problems. Here they are in order separated by issue.

Very low output with extremely high noise – This may be related to the following issue, but here is what I noticed. The audio output from a condenser mic is very low. Its seems that when I first plug the mic in the out is momentary better (not good) but when its running, there is hardly any output. When I turn the preamp up any I get unacceptable levels of noise. I would guess that about ½ up is the maximum usable gain, and it’s extremely weak there. When listening to a quiet signal ( a stereo turned down quite low with microphone close ) I don’t have enough output to drive the XL1 with either the Balanced XLR out into my MA100 with camera in Mic Level Input or Using the Headphone output into the XL1 RCA in any camera gain setting. The Audio Buddy can easily drive the camera with the gain set to line-in. The Pro Mix had a clip light, but I can’t get it to light from my condenser mic even with the ProMix levels set to 100%.

Poor Phantom Power Circuit – The phantom power circuit is poorly constructed. Since it runs on two 9V batteries or a 12VDC wall wart you either get 18V phantom or 12V phantom depending on the source. When I measure the voltage on a bare input the meter reads about 18v (on batteries) but when I add a microphone load the phantom power drops to about 6v. I did a similar experiment on the Audio Buddy and the phantom voltage of 30v from the Audio Buddy is consistent with a mic on or off. The phantom power issue might be one reason that I never get good output or reasonable noise.

Level Pots are VERY noisy – This was not a huge issues because I was planning on setting a level and leaving it there, but if you buy this don’t plan on making level adjustments while you are shooting. The pots sound like they came from an old dusty radio with scratchy noise from even modest adjustments.

Headphone level is not adjustable – This is a minor issue for me so long as the level was acceptable to begin with, but its not. When I peeked inside I noticed there were only two dual channel op-amps on the board. I think they are for the three inputs. My M-Audio box has about 6 or 8 I think and it doesn’t even offer headphone monitoring so I am dubious of the Pro Mix circuit design.

Finish is marginal – Again a somewhat minor issue if it worked, but the battery box is a piece of cardboard inside the case. The battery door requires a Phillips screwdriver to open. The battery compartment is bigger than the batteries so you basically drop them thru the hatch and they flop about.

I don’t want to sound like I am ranting, and I accept that its possible I just got a bad unit, but I spent enough time messing with this that I wanted to share my experiences. It might work fine as a 3 to 1 mixer for a few dynamic mics, but not as a mini field mixer.

The specs advertise 60db of preamp gain, which is what the M-Audio Buddy says, but there is no comparison as the Audio Buddy seems to have more than enough gain and I can barely hear this. Mine is going back to where is came from Monday when I get the chance. I will keep using the audio buddy and an extension cord until I come up with a better solution. If anyone has any thoughts around $150.00 or so I would be very interested.

You might consider the Behringer UBB1002 Eurorack mixer which offers battery as well as AC operation.

First thought is what mic are you powering with this? This Art Promix only has +12 v phantom, and I'm guessing you are plugging in a +48v mic.????

Could be most of the problem right there. Never used the Audio Buddy but others have said it's good sounding for the money.

Regarding the UBB1002 mixer, I have considered buying one, but it also only provides about 18v phantom power when running on batteries. This may cause some of the issues I experienced with the Pro Mix, but I guess I could go down to Guitar Center and try one out before I take it home. The form factor is not ideal for a field mixer, and I really wanted something the boom operator could carry around and adjust as required. I guess for about $100.00 I can only expect so much.

As for the 12v phantom (which is actually 18v on batteries), I have strongly considered this might be a huge part of the problem I have with the ProMix. I actually made a circuit mod to try and feed 36v to the phantom circuit, but this did not remedy the problem. For some reason (that I don’t understand electrically) the phantom power drops in half or more when plugged into the microphone. The Audio Buddy does not have this issue.

Owning two audio buddies, I can say they work quite well if you don’t mind being tied to shore power.

What mic are you trying to power from the Promix?

It's normal for phantom voltage to drop when there is a load, like a mic plugged into it. Should drop to 12 volts... what it's rated for.

The mic I was trying to power is a cheap MXL 991. Its rated for 48v +/- 4v. When I use the ProMix the voltage drops from about 18v to about 6v. When I use the same mic with the Audio Buddy (which actually only provides 30v phantom) the voltage stays around 26v or so.

The mic I was trying to power is a cheap MXL 991. Its rated for 48v +/- 4v. When I use the ProMix the voltage drops from about 18v to about 6v. When I use the same mic with the Audio Buddy (which actually only provides 30v phantom) the voltage stays around 26v or so.

Usually when a mfgr says "48 volt +/- 4 volt" they really mean it, 44v-52v and anything much under that is just not going to work. Even the Schoeps CMC641, a standard boom mic of Hollywood studios that costs well on the far-side of a kilobuck, just won't work worth a d*** with much less than full rated 48 volt phantom.

I'd say you got what you paid for :)

This is an excellent review. I really appreciate your time and effort.

I really have a big problem with any mfgr who calls 12 V Phantom.

Sound Devices, OTOH, makes mixers that use a few as 4 AA cells that DO provide 48 V DC Phantom. And their supply also provides the current to power four mics.

That's another issue for cheaply designed mixers that claim 48 V DC Phantom. Yes, they are 48 V DC, BUT they don't have enough amperage to power more than one mic or they don't have enough amperage to power even one mic that requires 4 mA.

I've had shooter/editors call me from the edit bay to tell me how surprised they are that the sound I provided for them sounds so good. The Sound Devices gear is really quite good. There are deep technical reasons why it's that good. Put simply; excellent design with components many others leave out to make a cheaper product to lure buyers.

SD mixers are not like consumer camcorders. SD mixers will be around to feed your camera for years. Someone else used the line, "I can't afford to buy cheap audio gear." Bingo!

The problem is, most people have no idea what really good sound sounds like, except for what they hear in the movies. They get trapped in the budget bin. I had someone buy my little book last week. Turns out he lives about ten miles from me. I invited him over. During the visit, I got the chance to show him my mixer and what a Schoeps cmc641 sounds like.

It was an ear opener for him (as it was for me the first time I heard one some years ago). He left with a new awareness of how good sound can be.

I urge all folks on this board to raise their sights and do what they need to do to improve their audio. It's one of the CHEAPEST investments wih the BIGGEST return on investment.

Regards,

Ty Ford

I urge all folks on this board to raise their sights and do what they need to do to improve their audio. It's one of the CHEAPEST investments wih the BIGGEST return on investment.


Agreed 110%!

OK, I admit it, I'm biased. I'm not a filmmaker, I'm not a camera operator, or a director, or a gaffer. What I am is a sound recordist. This past weekend, I taught a class on on-location recording (which is why I bought your book Ty, so people could see what was on the market book-wise). Almost everybody there was there not because there loved audio, but because they were filmmakers who found out the hard way that having a gorgeous looking movie isn't all that makes a movie. Unless you're making a silent film, sound makes or breaks your movie. You can have a great looking picture and a great storyline, but people will think it's a bad movie if the sound is bad. However, if the sound is great, people will forgive poor lighting and poor picture quality.

Quality sound equipment is expensive. However, the flip side is I have 15 year old microphones that sound as good today as they did I got them. boom poles that have been beat up, but they still work. Audio equipment simply doesn't go out of style that often. Things may be a bit harder to find (analog tape, DAT tape), but unlike most camera gear, it doesn't seem to go out of style that quickly.

Wayne

Hi Ty:

I really appreciate your knowledge and advice you lend here. What are your thoughts on the PSC mixers? It seems every sound mixer I hire uses the SD mixers and I know that they are good but I own the PSC M4 MKII and I also have the older Wendt X3.

For some reason, the ergonomics and layout of the SD mixers bug me although I know that they perform well. The PSC is getting a bit long in the tooth, we have been using it for about 7-8 years and I am thinking about a new mixer and wanted your opinion on what else to consider besides SD. The PSC, for the record, has been basically flawless and bulletproof and sounds good too.

Dan

Hello Dan,

PSC has a good reputation as does Wendt in the really Pro market.
You won't see them in Guitar Center. :)

As long as you're buying high enough in their line, I'm guessing you'll be OK.
I don't know their line well enough to comment much, but other pros I know do use their gear.


Regards,

Ty