Strange issue with stereo IEM mix on QU-PAC?

Qu Qu General Discussions
1

Had a strange one tonight with my QU-PAC. I run stereo IEM’s for a small rhythm section (drums, bass and keys) and for some strange reason the drummer wasn’t getting anything apart from keys in one ear!?

I am using exactly the same scene that is saved on the QU-PAC which has been working perfectly until last night!?
The drummers IEM pack is the Behringer P1 and the other IEM packs were the Fischer InEar Stick and Behringer P2.
There was no backline and I had bass, kick drum and mono OH, 2x keys and four vocal microphones going through FOH and IEM’s.

I had a look at the drum stereo IEM mix 5/6 in QU-Pad and he had the keys pretty low but it was only in one ear. However, even more odd was he didn’t have any drums, bass or vocals in his IEM’s but those were turned up seriously way past unity at +10dB! I double checked that the leads were connected to the correct mix output, checked panning + levels and these were all correct. I also checked gain staging and also tried him on a completely different mono mix2 output with a different cable and his IEM pack switched to mono but nothing seemed to rectify the issue!?
According to his monitor mix the drums and bass should have been extremely loud but all he had was a moderate amount of keys in one ear!?
Both the keys and bass iem mixes were working perfectly!?

If he was getting keys, drums, bass + vocals in one ear piece I would put it down to a faulty connection or broken earbud!? However, the fact that he wasn’t getting any drums, bass or vocals despite them being turned up to max is odd?

Does anyone have any ideas as to what is causing this?

2

Just to double check they were using the Behringer P1 two channel stereo belt pack head phone amp?

Were you connecting it with two lines from mix 5-6 outputs?

Was the stereo mono switch on the P1 in stereo?

Try plugging in a set of headphones to the headphone jack on the mixer and PFL the 5-6 mix to see how it sounds.

Is there a chance (if using two cables) that the polarity if flipped on one cable and creating a lot of phase cancellation?

3

Ok but of a rookie error!? I hadn’t realised the Behringer P1 uses a left and right input as I didn’t look at the drummers pack! I presumed it was the same single stereo input like the P2 and Fischer InEar stick!

I have Y cables made that converts both the outputs of a stereo channel to a single XLR to use with the Fischer InEar stick and Behringer P2 and that’s what I sent the drummer to his P1 pack. He also had it set to stereo!!

4

With that it was some massive phase cancellation causing the issues. On the Ear Stick and P2’s there is a switch inside that selects either balanced mono input or stereo input with a custom cable as you had made up.

5

Yes totally realise that now :man_facepalming: Thankyou for you help :+1: