QU-SB Aux Audio Level Drops

[John]

I am using the aux7-8 stereo pair to feed audio to a video recording system. We just got our QU-SB back from the shop where they replaced the audio board because everything stopped working. The behavior we are now seeing is that the right channel output level will drop 30db for a while in the middle of the recording and then come back to normal. The specific input being used is a single microphone with LS set to center. According to the user, the bargraph indicator looks of and no level changes are being made during the “quiet” times. I am trying to get a multi-track recording so I can confirm there are no input level issues and the stereo record function is ok.

Any thoughts on the cause/correction would be appreciated.

John

[volounteer]

@John

I would ask the repair shop ASAP and let them know the problem is there.

Does it do that on other outputs?
Does it do that with other inputs?
Does it do it exactly the same time into use each time it happens?
Is the single mike coming in mono or stereo channel input?

[John]

I am going to open a ticket with the vendor (again) It lost one output to the video last fall so I patched it to another aux pair. The mixer failed completely the Thursday before Easter so I sent it for repair.

Other outputs – not sure since in today’s COVID times we are recording for video streaming
Other inputs – No, dropout id independent of mike in use.
Same time – No, random throughout the hour long record cycle.
Mikes are on mono channels generally mixed to the center. Stereo record was established for flexibility for other possible uses.

[Mike C]

On the output of the mixer swap the cables around that are feeding to you video system as in taking the cable plugged into the the right output and plug it into the left, take the left and plug it into the right.

Use the system a while and see if the problem moved with the cable swap, if the right channel of the video system that is now plugged into the mixers left output still has
the problem the issue is in the cabling or the video system.

If the problem shows up on now the left channel of the video system that is connected to the mixers right channel output the problem points back to the mixer.

What are the audio connections to the video system inputs?

[John]

Mike C

Thanks for the suggestions. Cabling is good – while the mixer was out for repairs, I had a Mackie DL1608 installed that was working fine. The audio path goes from the mixer aux outputs through fixed cabling to the video position 150′ away. At the video console the signal goes through a distribution/impedance matching amplifier to two DVR’s I have switched to a different aux pair for this week and am running sound for the recording so I will see what happens.

[Author]

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