PXW-X70 Wonky Sound issues

[Craig Evans]

Hi. Hoping someone has "been there" and can tell me a "try this" to get past a sound issue.

Been using these cameras (two X70s) to record Old-time Musicians in the field. I use Sennheiser lavs (ew100s) for conversations, but often my subjects will pick up an instrument to demonstrate something. If the instrument is screechy (defined as sharp or high frequencies common on fiddles, hammer dulcimers and banjos), it seems to "wonk out" my X70s audio and I end up recording a wonky/digital soup mix from that point on. Once it happens, I either have to stop and reboot (really offsetting) or just keep filming hoping I can use my backup tracks (Zoom H5). Hate that.

I'm wondering if anyone has found some MENU settings they use to cut the high end shock to the X70's audio so it quickly recovers and records correctly. Any other suggestions welcome.

1:40 audio clips of 4 sound issue samples here:

YouTube (Short URL)

Thanks for any help!!

Craig

[Jeff Pulera]

I've used the X70 a lot at music events and never had that issue, but not using lavs either. I typically use MANUAL record levels with a shotgun, recording same signal to both channels, but at two different levels. One channel low, the other louder, so as to avoid blow-outs. I can choose between channels when editing.

To me, it sounds like you have digital clipping - audio is recorded too loud, like maybe you have record level set for speech, then the instrument is pegging the meters? If using AUTO record level, that could be a factor that I've not experienced using manual rec levels.

Thanks

[David Barnett]

Tough to say, however where are the lavs placed? On the interviewees shirt collar like an interview/deposition? If so, if its there as they play the instrument that would make sense it would sound distorted. To an extent the mic is behind or overtop the guitar/banjo, and the bassier sounds travel slower & up whereas the hissier treble would likely project straight out & reverb off walls etc.

I agree also about not using Auto, not sure if you are. I would use manual & even a lav on Channel 1 & place an XLR shotgun into Channel 2s input & record seperate to Channel 2 using shotgun & manual.

[Craig Evans]

Thanks guys. I run audio on Manual.

I'm cutting my ew100s back to -20db (from -10) as an added precaution. (Sigh). I was just hoping there was something else I could do. I'm a one-man band, here... can't afford an audio guy. :)

Thanks for the input.

Craig

[Bill Ward]

Do you have the ability to run a shotgun on a stand to record the instruments? Maybe recording to a Zoom or remote recorder?

[Craig Evans]

Hi Bill

During an interview, I run the Zoom H5 separately... as a stand alone to record the music and background sounds. My problem is when a subject needs to play an example and they're wired to my ew100s. I've got the Senn lavs at -20db to try and shield them and my camera, but if/when it happens (i.e. a subject plays a screechy fiddle), the integrity of my audio is in jeopardy. If I keep filming, I won't know the outcome (did it wonk?) until playback. Or I can shut down and power up again and remove the fiddle from the room. :(

I guess I should just restrict playing to the appropriate section... but with some of these folks, they "talk" through and with the music. Many enjoyed just sitting with an instrument in their lap.

On the upside, of 118 of these interviews, only 12 have gone wonk... to various degrees. I can live with some phasing sounds (the first couple of examples). But the hammer dulcimer really did 'em in.

[Paul Anderegg]

Typically, you will want to adjust your audio levels subject to subject scene to scene using only the TRANSMITTER control when operating a wireless mic. The newer systems are digital, and as others are saying, have what you might consider an audio "knee" circuit, but instead of compressing highlights, it compresses audio at higher frequencies, giving it that echo/garble/low bitrate mp3 sound.

You want to set your transmitter mic level, then adjust your camera input level and record level so it peaks the same. If you set your MIC GAIN level on the transmitter TOO HIGH, and set your RECORD LEVEL lower on the camera to bring your levels to "correct" on your VU meter, you will end up with that digital juice sound...this is because the transmitter encoder is attempting to take all that overmodulated audio and squish it down into the compressible range.

You can test your levels by talking quite loudly into your mic, and listening for any tinniness or low quality mp3 sound in the S's and such, high frequencies.

Paul

[Craig Evans]

Hi Paul. Thanks for your helpful insights.

Because I'm often not allowed the luxury of time while setting up (my in-the-field subjects start talking as soon as I arrive), I try to preset both the TRANSMITTER (ew100s) GAIN (-10db right now... I've adjusted) and the X70s preset RECORD LEVEL input at 18. I then (last) dial in my camera's (BEACHTEK's MIXER) audio when mics are placed.

Might the 18 on the X70 be at a better (safer) level to avoid the digital juice sound?

[Paul Anderegg]

The compression only occurs on the transmitter end, when it encodes levels for transmission. I guess what i am saying is that you need to be set up where your camera input level and record level are FIXED. You should only really be adjusting the mic/transmitter gain if necessary. You can fudge a little if needed on the camera side. Many newer mics like the ABX series do not have adjustments on the transmitter side. On my AVX, if I set the camera input level too low, and set a too high receiver OUTPUT level, I will get the highly compressed digital juice effect as well, as the receiver tries to pump the entire signal range into whatever it is being told by settings, that the camera is looking for.

Paul