Failure: AT3031
 

Guys I pride myself in being incompetent, but I think I peaked and I really need some help.

I can't get any clear audio from my AT3031. Its new so I don't know what to expect, but I think I should be able to hear at least something besides air static. The only time I hear anything is when I yell into the mic from an inch away.

I've tried two phantom power device mixers. One is an ART ProMix 3 channel- no success. The other I just got today. Personas TUBEpre (single channel).

I've connected the mic to the mixers and the mixers to two devices without success. One is a Sony VX2100 through a Beachtech. The other is an Edirol R-09.

I've tried to connect to R-09 using XLR out to Mini. I've tried connecting to the Beach using XLR-XLR balanced and unbalanced 1/4 to XLR.

I've adjusted all the inputs and gain controls and I'm not getting anywhere.

Any clue as to a starting point for either the R-09 or direct to camera.

Thanks,
Scott

Yes, it sounds like your mic is not getting phantom or battery power.

If the mixer is xlr in and has phantom, your best bet is to continue testing with that. Phantom needs all three wires found in an xlr cable to work. It won't work with an unbalanced 1/4" on one end.

Mic to mixer via xlr. Headphones from mixer. When troubleshooting, it helps to use as few devices as possible.

Does your beachtek have phantom? Are your xlr cables good?

Batteries - are they new? Put in the right way?

Do you have a buddy who is more experienced with audio who could confirm a dead mic if none of the above is working for you?

After that, it's warranty time.

Scott,
Trace it step by step.

Use a multimeter to check that you have +12 volts or +18 volts between pin 1 and pin 2 and also between pin 1 and pin 3 of the ART mic input channel connector you are going to use. If you've got it, then plug the XLR cable into the mic input on the ART. Then check that you have the same voltage at the other end of the XLR cable before you plug it into the mic. Turn off the power before pluging the cable into the mic. When you turn it back on, check with headphones in the ART's headphone jack while you speak into the mic.

Ooh I like that Fred! Multimeter. You know me better than anyone and you know I never heard of one of those.

Anyway, I did what Seth said about plugging in the phones to the mixer, and I heard something! I used the ART. From there I went into the camera's Beach (which is not phantom power). I talked in to the mic and got some sound. I'm also able to tap and scratch the microphone head and get noise. There's a good bit air sound, very noisy and thats dissapointing because I expected it to sound better than my Rode VM.

I could not achieve the same results (poor as they were) with the Personas. I think that tells me the Microphone is working and the XLR cables are good since it worked with the ART.

I think it also tells me the Personas isn't working. The gain dial sticks a bit, which I don't think it should. The VU meter needle doesn't move at all.

I'm real curious as to what I should expect to hear if everything is working properly. I know I can vary several dials on several pieces of equipment that will make a difference for better or worse.

Camera Audio
Beach Audio
Gain Control on Mixer.

The concenus when using the VX2100 is to set the audio meter at halfway and adjust the volume using the Beach. I don't know what the rule is when adding the mixer with hits Gain control knob. Which one is the priority?

Anyway, am I right to be dissapointed in the large amount of hummm I'm hearing? One person I talked to blamed the ART and it accused it of being the noise culprit. I got the Personas at her suggestion.

Thanks,
Scott

A multimeter is a $20-30 item at Radio Shack. It can check voltages and other things, so they call it a mult-meter. I thought we had discussed using one before, but maybe that was someone else. It would be a good thing to have.

Anyway, just to test, set the VX2100 at mid gain, the beach at full gain in mic level mode. Plug the headphones into the VX2100. Then bring up the channel gain knob on the ART as you speak. Do you get a usable level of sound and a good meter indication on the VX2100?

If you do and there's a hum, are you using the ART with battery power or with an AC adapter?

How many different xlr mic cables have you tried between the mic and the phantom power sources? If more than one were they from different makers or bought at different times?
I would suspect that you have a cable problem or a severe level mis-match somewhere in the setup.
Can you borrow a known good cable and a typical mixer that supplies phantom power, like a Mackie 1202 or similar?

Tried that Fred and it worked with the sizable hum. I've been using plug in power on the ART. I guess I got to try battery huh? I'll also stop by radio shack.


Jay- I'm using a new Canare Star (courtesy of Fred's suggestion) from the Mic to the Mixer. I've used several other XLR cables from the Mixer to the Beach's camera. And this brings me to a stupid question about balance/unbalance.

All are M/F XLR Cables balanced? Do cameras receive audio signals as balananced or unbalanced? I see on the mixer that it is supposed to send a balanced signal. The tech reasons between bal and unbal seemed over my head the last time I looked into it. I just wanted to know if there something obvious I should or shouldn't be doing when thinking about balance.
Thanks,
Scott

I have a pair of 3031s and they absolutely and positively require phantom power.

Which Beachtek model did you try it with? To get the needed phantom power you must be using either the DXA-6, DXA-8, or DXA-10. Other Beaachteks do not have phantom. An unbalanced 1/4 connection will not support phantom power (not sure where you tried that as Beaches don't have a 1/4 input AFAIK). The Edirol R-09 does not provide any phantom at all.

What led you to believe the preamps weren't working with the mic - neither has a headphone monitor capability and they won't drive cans or a speaker by themselves. So how did you try to listen to the signal when you tried the two preamps?

The ART preamp does supply phantom but it's pretty anemic at only 12 volts - while A/T says the mics work on 11-52 volt, 12 seems pretty marginal to me. Are you certain you had the mic plugged into an XLR INPUT instead of an XLR OUTPUT and are you certain you actually switched the phantom power for that input ON (dip switch slid to the down position), the preamp was on (power light lit) and the gain control for that channel turned up?

The Presonus supplies phantom on the XLR Input connector only, not on the 1/4" instrument input. The impedance of the 1/4 input is also wrong for a condenser mic so you MUST plug the 3031 into the XLR input only, not the 1/4 inch.

Yes, XLR cables are balanced, although there really is no such thing as a balanced cable, only balanced or unbalanced inputs and outputs and cables to match them. Your camera is expecting a mono, unbalanced signal on the external mic connection AFAIK. That's what the Beachtek does - convert the balanced XLR in order to connect to an ubalanced mic input. Try connecting your stuff like this ...

mic-->preamp-->Beachtek-->camera or edirol.

I tested each of my AT3031s with my ART PhantomII supply, my VX2100 and a pair of headphones plugged into the VX2100.

AT3031 --> ART PhantomII --> VX2100 -->Headphones

My ART PhantomII is, of course a different model than Scott's ART Promix 3.

I used an XLR to 1/8" stereo mini plug between the ART and the VX.

With the VX2100 in manual audio mode, it's gain control set midway, the ART operating off its two 9V batteries and set for +48V phantom power, and the mic about 18" away, I easily got a level of -6 to -12 dB on the VX2100 with a normal speaking voice and it sounded fine in the phones. No audible hum.

I switched to +12V phantom, which you can do with the ART PhantomII. Interestingly, the audio level produced with the same speaking voice was initially very low, but rose to the same level as with +48V over a period of about 6-8 seconds. Obviously, the AT3031's circuitry is designed to give the same output with +12 or +48V.

I performed the same test using an AC adapter to power the ART. Same results, still no audible hum. I performed the whole set of tests with my second AT3031 with the same results.

The ART ProMix 3 Channel does have a phones jack in front so that's where I started with my ear phones and then moved to the camera. The Personas doesn't have phone jacks. It does have a 1/4 out but I learned phones don't work in them- as you said.

Yeah Steve, I used the XLR-In knowing it was suppoed to give Phantom. But if something doesn't work for me, I'm going to experiment with all the Jacks, which I did.

The Personas is dead meat. From what you guys said, it has a problem. The ART is a victim of user error meaning I need to use it better than I am.

Fred- No humm. This would be a good time for me to ask how you're playing back the audio. I just listened in through the phones on my camera. I didn't capture it and play it back on the computer/TV. Maybe I wouldn't hear the hum if I listened it to it on TV. I don't get to hear a lot of audio at the camera level. My daughter does most of that. I just get to edit it after the fact. I'm starting to think I'm on track of doing things right but my ear's expectations are out of line.

However, I definitely had a bad experience using the ART with the R-09. That was noisy.

I was just listening with my headphones too. If it doesn't sound good in the phones I don't expect it to sound any better on playback.No, your ears are right. It should sound fine in the headphones, plenty of volume, no hum and very little if any hiss (assuming the gain control is at half or less). If you use everything on battery power, the hum will be gone.

If you wind up with recorded hiss and 60 Hz hum, they're not hard to get rid of in post.

According to the specs, the ART ProMix 3 is only 18v phantom power. The AT3031 will work, but will be very low output causing you to increase the gain and thus increase the signal to noise ratio. (which sounds exactly like your problem) Get yourself a 48v phantom power supply and the mic will perform as it should. I would just buy a BeachTek with phantom power and you should be good to go.

~jr

Specs I saw quoted 12v - even worse!!

John and Steve, apparently you didn't read my post (#9) above. That's okay, I don't read them all either.

But the AT3031's circuitry is designed to output the same voltage level at 12V as at 48V. I guess it's just the max SPL and dynamic range that are degraded.

I did see your post and it was duly noted and accepted :) I know A/T says the 3031s are good with anything from 11 to 52. I've only used mine with 48v so I can't give first hand verification of their behaviour at lower voltages - I was just commenting that if John had noticed first hand there was serious degrdation at 18v, it would be bound to get even worse at 12.

I wish manufacturers would get their act together. While the formal specs for phantom allow for 12, 24, 36, or 48v there are a number of mics that just don't work properly with less than the full 48. I think its unconsciounable that manufacturers such as ART with ProMix and m-Audio with the Microtrack claim to provide phantom and yet send a lower voltage than many mics require. I realize they're are different levels of gear, but try plugging a Schoeps 641 or AKG 400 series modular mic into a Microtrack - won't work because the m-Audio only provides 32-36 volt phantom and both the mics mentioned required full-bore 48v to function properly.

Ditto. I read the whole thing.

Fred, Just to add to what Steve said: I have at AT897 which gives hotter output on 48v phantom power from my Sony Z1U than it does using the internal battery. So I know first hand that the phantom voltage definitely affects the output of the mic.

I stand by my comment. The mic will perform better with 48v than 12v phantom power.

~jr

No, my first hand experience is that it won't. And your first hand exprerience doesn't contradict that. What you learned is that 1.5V battery operation vs. 48V phantom operation definitely affects the output of the AT897.

1.5V battery power is pretty low, they probably couldn't compensate for that with the circuitry. And that's why AT specs two different sensitivities for the AT897, one for 11-48V phantom, and a lower one for battery--consistent with your experience.

They only spec one sensitivity for the AT3031--consistent with my experience.

And for the record I won't dispute your experience either, placing myself in the position of a mugwump, sitting firmly on the fence with my mug on one side and my wump on the other <grin>. While I've got a couple of 3031s, I only have sources of 48v phantom so I can't test them with other voltages in order to resolve the matter one way or the other.

No problem Steve--it's already been resolved. ;>)

You are correct, I was extrapolating one experience with low voltage for another. I don’t personally own any phantom power units that are not 48v so perhaps my observation in one low voltage scenario doesn’t hold true for the other. I stand corrected.

~jr

Thanks, John. And no one is completely wrong here. Just to round out the discussion I checked with Audio Technica. Their reply was that if the phantom power for one of their mics is specified at 11-52 then all the performance parameters are good for that range of voltage.

However, they do have some mics (AT4051 and AT4053 for example) that are spec'd for 48V. Those mics will suffer at less than 48V. There are probably many models of other brands out there that will also.