Sony Wireless Mic - Audio issue

[Oren Arieli]

I just added a (used) Sony UWP-D11 wireless mic to my kit, and on a shoot last week I got some terrible quality capture. If someone could help me diagnose this, I'd be grateful. It almost sounds like a phasing issue. I was less than 5ft. from the subject, batteries were fresh, I ran a frequency scan prior to starting the shoot and got a clear channel. This is a dual-diversity system and the RF was strong. Could this be a defective kit?

Wireless Audio Feed on Vimeo

[Jay Massengill]

Can you tell us more detail about the chain of connected equipment?

Was this the belt-pack transmitter with a lavalier mic or the plug-on transmitter with a regular mic?

Which output cable from the receiver was used and what connector type and recorder or mixer was it feeding into?

[Richard Crowley]

Sorry, I don't hear anything like "phasing issue" or any other kind of RF problem.

The sensitivity on the transmitter may be set a bit too high, I though I heard something approaching clipping. But, since you have not described the rest of the audio chain, that would just be a wild guess as it could be happening at the receiver or the recorder, or even down stream in post(?)

What I did hear that was rather annoying was pretty severe "gating" where the audio was muted between words. In combination with a rather poor (reverberant) acoustic environment, perhaps the gated tail ends of the room acoustics from each word are what you are hearing?

After double-checking the gain-structure of the transmitter, receiver and recorder/camcorder, my first task would be to GET RID of that horrible gating. If you need to apply such draconian measures in post-production, so be it. But to record tracks with that kind of processing is just unforgivable in my book.

if you don't like the reverberant acoustics of the space you are in, then move to a different space, dampen the reflections, or use a different (much closer) microphone technique.

Hoping that you did NOT buy a 700MHz (or 600MHz) band wireless kit as 700MHz is already illegal in the US, and 600MHz is sure to follow shortly as our politicians and bureaucrats get more greedy.

[Oren Arieli]

This was a belt-pack transmitter and a lapel mic being transmitted to the receiver mounted on-camera. Audio was set to manual and levels were set to just below -12db, no clipping, no post EQ added, I boosted the gain by 6db on the timeline, but otherwise, nothing else was added to the audio chain (pre or post).
As for the room acoustics, they weren't terrible by any means. There was a bit of background noise from people mingling about, but that is not what I'm hearing. It's likely a gating issue originating from the transmitter. (sensitivity was set to -3dB on the transmitter...RF was strong, and I'm on the 550-600Mhz range, if that makes any difference).

[Rick Reineke]

I'm not familiar with that particular system, nor did I listen to the clip, but an expander/gate type artifact can be a result of an improperly set-up compander.. i.e., both the transmitter and receiver must be set...the same. The receiver's squelch could also be set too high. ( if it has it) more ugly artifacts. Read the system's manual thoroughly and choose a clean frequency.

[Oren Arieli]

I did read through the manual and did a complete system setup, going through each feature, then confirming the operation in the studio...all was well, otherwise, I wouldn't have trusted it. I ran a frequency scan and then synchronized the transmitter to the receiver as per the instructions. Not sure if I could have done anything differently, which is what worries me. If it was a bad setup on my end, then I'd happily take the blame, learn from it and move on. This wasn't (necessarily) the case here, where I set it up by-the-book, doing everything I was supposed to do.

[Richard Crowley]

Since you bought the system used, are you sure it is the MATCHED transmitter and receiver. It sounds VERY much like mis-matched companding. The transmitter is compressing, but the receiver is not restoring the compression (corellated expanding)

[Oren Arieli]

They are both on the same block (30), and arrived with the original box. Not sure there is any other way to check they are 'matching', but I figure any Sony transmitter/receiver using the same frequencies is technically 'matched'. They are both the new digital hybrid type, so it's not like I'm mixing an older transmitter with a new receiver or vice versa.
Also, it was working on various tests, both before and after that particular shoot. So the issue is intermittent.

[Seth Bloombaum]

Originally Posted by Oren Arieli

...Also, it was working on various tests, both before and after that particular shoot. So the issue is intermittent.

Did you do testing in noisy environments?

Richard and Rick are both referring to something that I hear as well. There are other people speaking nearby. You can hear them when he speaks, but, when he pauses, you can't hear them. That is, there is a gating or expansion function operating when audio signal drops below a certain threshold.

They've mentioned companding / decompanding and squelch.

Reading through the manual, I find this in both the transmitter and receiver extended menu settings:

COMPANDER
Sets the operating mode of the compander.
UWP-D: High speech quality mode supported in combination with UWP-D series devices.
UWP: Mode supported in combination with Sony UWP-series tuners.
WL800: Mode supported in combination with Sony 800-series tuners.

• This function is displayed in extended mode only.
• No audio is output if the tone signal frequency is different due to the use of a combination of devices with different compander mode settings.

The manual doesn't mention this, but they MUST ALWAYS MATCH. The same compander settings MUST be selected on the transmitter and receiver. That's kind of a big oversight in the manual.

I don't find anything on receiver squelch settings.

I'd start with a factory reset of both transmitter and receiver, then do some testing of the compander settings. Likely it's the UWP-D setting that will be best. Be sure they always match. Test with various amounts of noise.

"It's intermittent"... well, that may be true, but it may re-occur at any time that signal and noise levels are similar to the recording you posted.

[Oren Arieli]

Thanks Seth. I think it comes down to a one-off situation (I hope). I confirmed that the compander on the transmitter/receiver are set to UWP-D, which I did upon first setup. If it had changed on it's own somehow, I could understand why the sound issue occurred in this instance.

[Karl Winkler]

Originally Posted by Oren Arieli

I just added a (used) Sony UWP-D11 wireless mic to my kit, and on a shoot last week I got some terrible quality capture. If someone could help me diagnose this, I'd be grateful. It almost sounds like a phasing issue. I was less than 5ft. from the subject, batteries were fresh, I ran a frequency scan prior to starting the shoot and got a clear channel. This is a dual-diversity system and the RF was strong. Could this be a defective kit?

Based on what I heard on the video clip, I will disagree with some of the earlier replies. I think the audio level into the transmitter was set too low. Because of this, the companding process is gating/expanding during the speech, where it should normally be out of the way.

If your peaks are reaching only -12 dB at the transmitter, this is definitely way too low. In general, you'll want your peaks to "bump" the limiters, i.e. the loudest passages should go full scale on your transmitter input meter. The average levels of speech should be perhaps -6 to -10 dB from full scale.

You may then have to back off our your receiver output levels to better match the camera or recorder inputs, or back off the camera audio inputs, either way.

[Greg Miller]

There is definitely some gating going on somewhere. You can hear the background conversations in the room while the talent is speaking, but when the talent pauses, the background goes away.

If I didn't have any info about the system, I would guess that the receiver is expanding, but the transmitter is not compressing. Therefore the expansion is acting like a noise gate.

If the transmitter was compressing but the receiver was not expanding, you would hear just the opposite: the background conversation would come up in level when the talent stopped speaking.

Since the OP says this is a properly matched system with few possible adjustments, I think the scenario described by Mr. Winkler sounds plausible.

I don't think it's squelch. That has to do with the RF signal level, not the transmitted audio level. Squelch would not be opening and closing based on the transmitted audio.

[Paul R Johnson]

I too feel the commander setup caused the problem - the pumping effect is a common artefact mismatched commanders. If you use an analogue Sennheiser transmitter on a Trantec receiver (as I have racks of them) the mismatch is a gentle compression that actually works nicely, but the reverse produces a very similar result to the one in the clip.