Headphone amp frequency response mismatch

I forget what thread I mentioned it in before, but the headphone out on my OT has the lows rolled off noticeably on the right channel but not the left, to the point where if I have, say, an analog kick routed to a thru machine and center panned, as I tune it down I can hear it hit a point where it starts to move left, and eventually there’s almost none of it on the right side. I don’t really care enough to bother sending it in for service or anything since the main outs are fine, but I wondered if anyone else had noticed anything similar with theirs. I haven’t actually done any serious listening or measurement or anything (I really just use the headphones for sequencing stuff late at night, they aren’t critical to me at all) but it’s VERY obvious with clean signals like an analog kick or sine bass.

I know early on a lot of people had issues with the headphone amp losing a channel or distorting, but I haven’t heard of this particular issue. I first noticed it last fall. It doesn’t sound distorted or quiet or anything, just a clean, smooth bass rolloff on the right side, I’d guess somewhere in the 80hZ-80hZ range.

I actually finally tried some different headphones and the problem persisted, so it isn’t the headphones.

if you want help you’re gonna have to narrow it down some #bigH_littlez_SI_FTW :wink:

as for your issue, ask support for a diagnosis, it may be a known behaviour and a simple fix for a competent electronics shop technician or hobbyist

1 Like

I’m fine with it as is, I was more curious to know if this is something other people have experienced.

I’m not sure how much narrower than what’s in my previous post I could get, other than loading a loop of monophnic white noise into the OT and comparing the response of the headphone channels with a spectrum analyzer. I’ll do that eventually (won’t have time today), on the off chance that I discover it’s something else. Lows roll off gently around 60-80hZ on the right channel of the headphone output but not the left, tested on multiple headphones and not present in the main or cue outs.

If it’s the headphone amp like it seems to be then it’s not worth the hassle of repair for me personally, but if other people have similar issues it would be worth discussing.

I was playfully fooling with your definition of a ‘range’ … (80 > 80)

I’m minded to check my own OT, no known issue though, but iirc, there was a spate of headphone out issues with earlier octatracks, manifesting in different ways afaicr

even if you don’t proceed with support I’m sure they’d advise you if it was a known/fixable issue - fwiw, you may get more readers/replies if you rename your thread [OT headphone out issues] or similar

1 Like

Just in case anyone finds this thread, I eventually determined that BOTH pairs of single-lead Sennheiser headphones (HD-280 and HD-590) were exhibiting similar behavior. I tried a pair of 650s (separate lead for each driver) and it sounded fine. I’ve heard of other people having problems with level mismatch on single lead Sennheisers before but I’d never heard anyone mention it being frequency selective and I hadn’t caught it earlier because I don’t mix through either of those headphones and it’s most noticeable on the really deep bass that tends to get shelved or completely highpassed in most mixes.

I’d written it off because it was there on both pairs of headphones I had handy, and it seemed more likely that the headphone amp would have a problem than that both pairs of headphones would have the same problem even though they were different models made over a decade apart, but it just goes to show you cant assume anything with this stuff, although I still haven’t actually had a chance to patch it in to a frequency analyzer and make sure.