Dear forum, my first post here and apologies if this has already been discussed before.
We use the CQ20B for band practice mainly as our in-ear mixer. Works great !!
Yesterday however we connected the XLR outs of the mixer to the active PA speakers in the room for testing and we noted that the volume of the input channels was very low compared to the USB/BT level.
So, to be a bit more precise:
My laptop was connected to the CQ via USB and used for MainStage keys. My Line 6 Helix was connected to one of the XLR inputs and input gain was set using the gain assistant.
My phone was connected via Bluetooth so as to be able to listen to Spotify.
I noted a huge difference in volume between the output of the Helix channel vs the bluetooth or USB. That is, the BT/USB was much much louder and I needed to pull back the main sliders by about 15 dB (don’t recall exactly, could even be a bit more) to get the level comparable to the level of my Helix guitar sound.
We then switched to the analog mixer in the room to figure out what was the issue. So, I connected the Helix to that mixer and the volume was way louder than what I could get from the CQ. That volume would be comparable to what the CQ would give for the BT/USB channels… which to me means there’s nothing wrong with the XLR outputs of the CQ.
So now the question is what I might be doing wrong? Is the “auto gain” perhaps too conservative when setting the “correct” input gain? Anything else I may overlook.
Thank you so much for any input/feedback/advice… we lost quite some time trouble shooting and still could not really figure this out.
Do you have any excessive compression or a lot of EQ being done on your Helix channel on the CQ specifically? This might account for the lower volume compared to the USB/BT channel, and why when you go direct from your Helix to the other mixer it appears to be much louder.
Only thing I can think of off-hand at the moment anyway.
Thank you! No, no processing at all. I’ll give it another go next week and increase the gain a bit more. I noted the USB signal went over 0dB slightly, whereas the HX signal stayed below. I’ll get there, probably being a bit too cautious myself as well…
You mention the metering for the USB channel is over 0dB.
This sounds like the computer/MainStage providing a level closer to 0dBFS, which is the equivalent to +18dB in the mixer.
0dB on the mixer meter = -18dBFS (in digital) = +4dBu at the mixer line output
So the CQ is allowing headroom (prevents clipping analogue signals that may come in too hot occasionally), where the computer doesn’t.
I this is the case, you can simply use the trim control available in the preamp section of the USB channel to reduce the input level coming from Main Stage until it sits around the same level as your analogue inputs.
Sorry for a very late reply, and thank a lot Keith !!
We’re going for a next trial tomorrow evening; I have trimmed the USB and BT incoming signals so that they more or less match the Helix connected to a physical input. I noted that when I use the gain assistant on the Helix the gain is around 12 dB. When I look at the gain meters when both the main fader as the “Guit_J” fader (which is my Helix) is at zero then the signal on the guitar channel peaks at the first " - " which I assume is around -5dB. The main fader peaks slightly lower than that even though I have no processing going on whatsoever. Attaching a picture (hop that worked…).
Either way, I assume this is the kind of response/ behaviour that the mixer was designed for. If you see anything strange then please do let me know. Need to admit that your technical explanation with the dB, dBFS and dBu is a bit puzzling me … but hey, I’m not an engineer, just an amateur trying to sound decent on guitar
