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Switcher audio level

PostPosted: Sun Dec 03, 2017 10:39 pm
by Cliff Whitney
We are using the BM TV Studio HD switcher and the audio levels are really low. We have a new digital audio console at church and they are sending the switcher XLR inputs one channel of analog audio that I have split for the two XLR inputs. The console output is supposed to be +4 dbu. which is about 0.7V.
I would think I shouldn't have to turn up the switcher sensitivity to get good results. So what are we doing wrong, only feeding one channel and using a splitter? I'm only showing a minus 20 for normal levels.
Hope you can help, thanks.

Re: Switcher audio level

PostPosted: Mon Dec 04, 2017 10:38 am
by Xtreemtec
The inputs are really low. Our experience is that we have to gain the Audio board output more then often.

Also you can push the audio levels a bit more in the Atem audio panel to go over the 0 line.. ;)

Re: Switcher audio level

PostPosted: Mon Dec 04, 2017 3:40 pm
by Cliff Whitney
Thank you, That gives me some sense of what is happening. What is the sensitivity of the XLR inputs?
They say 0 db but that doesn't say much. Could you expand on that some?
Cliff

Re: Switcher audio level

PostPosted: Mon Dec 04, 2017 9:27 pm
by Gary Adams
Hello Cliff. The XLR inputs to all ATEM switchers (with XLR inputs) is +4 dBm. This is usually but not always a 0 VU on many audio consoles. When you feed a +4 signal (especially tone) it should read -20 dBfs on the ATEM meters. If your console is +4 and you have wired balanced (not unbalanced) to the ATEM, you should see these results. Note that a VU meter has different motion than a dBfs meter but the tones should tell you where the levels are. Also note there is +10 dB headroom on the analog inputs which means a +14 dBu or -10 dBfs will be the maximum you can send on the analog channel. If you are splitting the cable to both inputs, expect some drop in the signal level.

Regards, Gary

Re: Switcher audio level

PostPosted: Thu Dec 07, 2017 4:56 pm
by Cliff Whitney
Thanks Gary for the great reply. So the meters on my BM Multiview monitor show a lot of headroom?
And normal voice levels only read about -20 dbs? Last question: Are the meters showing dbs or dbu?
Thanks again, Cliff

Re: Switcher audio level

PostPosted: Thu Dec 07, 2017 9:58 pm
by Gary Adams
Hello Cliff. The ATEM meters in the software and on the Multiview are dBFS, or dB Full Scale. It's a digital representation of the signal with peak style movement. -20 would be the normal 0 VU (here in the US) and would be a +4 dBm or dBu on the analog outputs. So with the digital signals you have 0 dB of headroom and then all bits are on. On the analog side you have 10 db of headroom, so when the meter hits the red on the analog side, analog will do it's sort of clipping thing. Tone is about the only thing that tells you where things are. Feed tone through the system and you should see where the levels are.

Regards, Gary