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PROBLEM Sounddevice 633 MIC Outputs

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PROBLEM Sounddevice 633 MIC Outputs

Postby Rian032 » Fri Oct 30, 2020 12:49 pm

Hey Guys,

I couldn't really get help from the Sounddevice support, maybe somebody here has a little secret for me.

The Problem:

I'm trying to send audio Signal to a Camera via my Sennheiser eg 100 g3 wireless system. When the outputs (XLR L/R) of the 633 are set to MIC and the inputs of the camera of course aswell are set to MIC I'm getting horrible static noise at the end so that the audio will be unusable. When the whole audio chain is send via LINE from the outputs and at the input everything is fine.
So far so good. This wouldn't bother me that much, as that the LINE thing works.
But when I use the same setup (Sennheiser wireless, same Camera) but change the 633 with a Sounddevice 302, everything works great. Even if the outputs of the 302 are set to MIC and so on and so on, so with the 302 both versions work.

So then I tested and tested and blabla, which really confuses me is that when I connect the 633 via cable to the camera the MIC output works as good as the LINE output -> no static noise.

But why does the Wireless version work on the 302 with MIC but not at the 633?! I really can't see the point......

Does anyone know a thing?
Rian032
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Re: PROBLEM Sounddevice 633 MIC Outputs

Postby Hugh Robjohns » Fri Oct 30, 2020 1:04 pm

Rian032 wrote:I'm trying to send audio Signal to a Camera via my Sennheiser eg 100 g3 wireless system. When the outputs (XLR L/R) of the 633 are set to MIC and the inputs of the camera of course aswell are set to MIC I'm getting horrible static noise at the end so that the audio will be unusable. When the whole audio chain is send via LINE from the outputs and at the input everything is fine.

I imagine this is a gain-structuring problem with the wireless transmitter and/or receiver setup, and most probably inappropriate output level setting of the receiver.

Setting the TX to accept a mic level input doesn't mean you'll get a mic level output from the receiver. You need to set that separately.

I don't know precisely what you mean by 'horrible static noise'. To some 'static noise' means the kind of noise you get when a receiver isn't getting a good signal... but to others it's gross overload distortion...

I've no idea why the system works with one mixer and not the other... that would take some careful hands-on experimentation and measurement to figure out.
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Re: PROBLEM Sounddevice 633 MIC Outputs

Postby Rian032 » Fri Oct 30, 2020 1:27 pm

Hugh Robjohns wrote:
Rian032 wrote:I'm trying to send audio Signal to a Camera via my Sennheiser eg 100 g3 wireless system. When the outputs (XLR L/R) of the 633 are set to MIC and the inputs of the camera of course aswell are set to MIC I'm getting horrible static noise at the end so that the audio will be unusable. When the whole audio chain is send via LINE from the outputs and at the input everything is fine.

I imagine this is a gain-structuring problem with the wireless transmitter and/or receiver setup, and most probably inappropriate output level setting of the receiver.

Setting the TX to accept a mic level input doesn't mean you'll get a mic level output from the receiver. You need to set that separately.

I don't know precisely what you mean by 'horrible static noise'. To some 'static noise' means the kind of noise you get when a receiver isn't getting a good signal... but to others it's gross overload distortion...

I've no idea why the system works with one mixer and not the other... that would take some careful hands-on experimentation and measurement to figure out.


I think static noise is probably the wrong term, sorry I'm from germany, I think a lot of hiss (?) correct me if i'm wrong, is the better term.

Yeah I kind off tested most of the output gains at the receicver and it doenst change anything for the outcome, seems like a problem with the output gain of the 633 combined with the sennheiser....its just really confusing with the 302 as there are no problems at all.
Rian032
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Re: PROBLEM Sounddevice 633 MIC Outputs

Postby Hugh Robjohns » Fri Oct 30, 2020 1:42 pm

Rian032 wrote:I think static noise is probably the wrong term, sorry I'm from germany, I think a lot of hiss (?) correct me if i'm wrong, is the better term.

No need to apologise -- your written English is way better than my written German! ;)

Yes, hiss might well be a better term -- although without actually hearing it it's still open to interpretation, of course. But hiss would suggest a gain structuring problem.

...its just really confusing with the 302 as there are no problems at all.

Yes, that's troubling me too... I'm not very familiar with the 633, and a scan of the manual doesn't give any useful information about the nominal signal level when the main outputs are selected to be mic-level.

Have you tried sending tone from each unit into the radio mic transmitter to see what levels you're getting and whether they are similar?
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