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Left channel and right channel of DAW sound VERY different!

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Left channel and right channel of DAW sound VERY different!

PostPosted: Sun Feb 10, 2019 5:08 pm
by Cosmic Audio
Hi all

I'll try and make this as concise and easy to understand as possible!

Using Logic pro, I panned a guitar from the right channel to the left channel whilst experimenting with panning positions for a mix. I noticed a big difference in the sound, so I solo'd it and the difference became more apparent from one speaker to the other.

Suspecting a problem with my monitors, I tried various different test tones - sine waves at various frequencies and white and pink noise. Again, a noticeable difference in sound quality when panned hard left or hard right within the DAW.

My monitors are three-way active ATC SCM150 style (they're actually very early Quested's but have the ATC drivers in them) that are run from an active crossover set at 380hz and 3.5khz running three amps that each drive the bass, mid and treble drivers. I suspected someone might have dinked with the crossover or amp levels, so checked that first.

That was all fine, and the difference was most pronounced in the mids - if I turned off the bass and treble amps it was more apparent. So I suspected a problem with the mid drivers. "Check it on headphones in case it's coming from somewhere before the crossover" I said to myself.

Well, same thing on headphones! A noticeable difference in sound from the left channel of Logic than the right when using the pan on the channel strip playing any signal, test tone, guitar, piano, whatever. And if I swapped the headphones around on my head, the difference was the other way around, so that rules out my ears!

So, working backwards down the chain, I then suspected my monitor controller (Drawmer CMC2) and audio interface (Focusrite Claret 8 Pre-X). Swapping the output cables over also swapped the difference, so that ruled out both monitors and headphones, but not necessarily the interface or monitor controller.

So I checked on a different pair of headphones, on a different computer, directly from the headphone out on the second computer. Low and behold, the same thing, and it's even noticeable on laptop speakers if you load white or pink noise and hard pan from left to right

Since then, whenever I'm in the company of a friend with a DAW on a computer, I've performed the same experiment, with the same results, so my conclusion after much experimentation is that Logic Pro X puts out a noticeably different mono signal from the left channel than it does from the right - and so does Studio One. If I leave the signal centred in Logic and run it through an analogue mixer and use the pan on that, in the analogue domain, it sounds identical.

Am I going mad, or is this a 'thing' with DAWs I didn't know about? Please try it for yourself - load some white or pink noise and pan from left to right. It sounds different at the extremes of left and right! Very different!

Hoping one of you guys and girls with much better technical knowledge of how panning works in a DAW will be able to answer this for me.

Many thanks
Mark

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Sun Feb 10, 2019 5:38 pm
by Ramirez
Hmm.

Does it also happen when you sweep from left to right, but with your monitors set to mono on the Drawmer? That way you should still hear the signal centrally, but the DAW will be sending out a different signal as you sweep. Is there a change? Have you got any plugins on you Logic master channel?

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Sun Feb 10, 2019 5:49 pm
by desmond
Cosmic Audio wrote:my conclusion after much experimentation is that Logic Pro X puts out a noticeably different mono signal from the left channel than it does from the right

I very much doubt it. Logic has hundreds of thousands of users - if this was a "thing" there would be huge noise in the internet about it, and it would get fixed, or no-one would use Logic..!

You've got something going on in your system you need to narrow down the cause of.

Cosmic Audio wrote:Am I going mad, or is this a 'thing' with DAWs I didn't know about?

No, it's not a thing with DAWs. I don't think you're going mad, though! ;)

Cosmic Audio wrote:Please try it for yourself - load some white or pink noise and pan from left to right. It sounds different at the extremes of left and right! Very different!

Are you doing this on in an empty, default fresh template project, or one of your own with routings already set up?
Can you put up an example project that shows the issue for you?

Also - noise/test signals can be deceiving - I'm only with my laptop at the moment, but I set up a white noise oscillator in Logic, with an analyser on the main output channels. The analyser clearly shows that the signals are essentially identical in terms of frequencies when panned left or right, as expected.

However, in my little Sennheiser earbuds (no reference quality here, but it's all I have to hand), when panned to the left (left ear) I *hear* more low energy (and a little less high I think) than when panned to the right.

If I swap the earphones over, so the left earbud is now in the right ear and vice versa, the differences stay in the same ear, indicating that my left ear seems to be hearing a bit more low energy than my right. So in this case, I *can* hear a difference, but I'm reasonably confident that it's my ears, as the tech suggests the channels are identical. I can't rule out the OSX audio system as like I say, I'm away from home and my audio interface/speakers etc. I'll have another look in a day or two...

Also, when panned away from the extremes, with the white noise test oscillator in Logic, there seems to be a certain amount of cancelling going on, so when you feed in a little from the right (ie pan a little away from full left, you can hear the frequency response change a little until it settles back in a few dBs later.

(Incidentally, I did go through some related weirdness about this a bit a few months ago - I had connected up my main speakers in my little room and the sound was really bugging me for ages. It turned out, after a certain amount of troubleshooting I had a combination of issues going on - firstly, the speaker positions, versus the listening position and the room config basically were terrible and I was sitting right in a deep bass null causing all kinds of nasties - I had to move to a less convenient speaker position, but with a vastly improved sound - narrower width, a little closer to the speakers, less wall interference. Secondly, I had a dodgy speaker cable issue to one speaker, which when fixed also removed the audible differences between channels that I was hearing. It's much better now, and at least workable for an untreated room.)

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Sun Feb 10, 2019 6:54 pm
by Cosmic Audio
Thanks for your very detailed reply Desmond!

So, I've replicated this again this afternoon, with a fresh default-no-template Logic project, one mono audio channel and no plugins other than the Logic stock test tone generator, all faders left at zero.

On my speakers, I can clearly hear more mid frequency information when the signal is panned hard left than I can when it is panned hard right. That gives me a little more low information too.

On headphones, (Beyer DT990) I hear the same thing. If I swap the headphones around so the left phone is on my right ear and the right phone on my left, I hear the same thing from the technology, but in my other ear.... if that makes sense! So If I automate the pan, what sounds more mid-centric in my left ear sounds more mid-centric in my right ear when I swap the headphones around. So that rules out my ears, but not my sanity haha!

I can also clearly achieve the same results on a different computer (mac pro laptop) using either the inbuilt speakers, or headphones plugged directly into that. Interestingly, I hear the same thing in both Logic and Studio One Professional (the only two DAWs I have at my disposal.

Even more interestingly, if I send the test tone in dual mono out of my interface into a stereo channel on my analogue mixer, then hard pan using the mixers pan pot, it sounds identical in both channels on both monitors and headphones.

So that suggests to me that Logic is putting the same out of it's left channel as it is the right, but something is going awry when I use the pans in Logic as opposed to the analogue mixer. And the same results in Studio One. I'll see if I can put this into a video somehow, and record the audio in a way that is clearly noticeable when the video is played back. Very confused....!

To add to the confusion, I downloaded some test tones from the link below to assess the inter-modulation distortion performance of my convertors at 96khz, and although I can clearly see the audio on my meters and yet hear nothing when the audio is panned centrally in Logic (as it should be if my converters are up to scratch), I can clearly hear it (and very differently) if I hard pan left or right in Logic. Does that help at all?

https://people.xiph.org/~xiphmont/demo/ ... ml#toc_1ch

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Sun Feb 10, 2019 7:25 pm
by desmond
Cosmic Audio wrote:So that rules out my ears, but not my sanity haha!

:lol: :thumbup:

Cosmic Audio wrote:I can also clearly achieve the same results on a different computer (mac pro laptop) using either the inbuilt speakers, or headphones plugged directly into that.

And you hear those both via your external audio interface, *and* the default Mac audio outputs?

Cosmic Audio wrote:Even more interestingly, if I send the test tone in dual mono out of my interface into a stereo channel on my analogue mixer, then hard pan using the mixers pan pot, it sounds identical in both channels on both monitors and headphones.

Cosmic Audio wrote:something is going awry when I use the pans in Logic as opposed to the analogue mixer. And the same results in Studio One. I'll see if I can put this into a video somehow, and record the audio in a way that is clearly noticeable when the video is played back. Very confused....!

Do you get any differences panning a stereo signal, vs panning a mono signal (panning stereo signals is just a balance control, ie changing the volume left and right).

Also be aware that there are a few panning modes and pan law settings in Logic, but in any case, I can't see why these would result in a change of signal like you are hearing.

I'll have a look into this in a day or two, in the meantime, I'm sure others will come along with some useful input.

The fact that you are hearing differences across multiple DAWs, multiple interfaces, multiple computers, and multiple monitoring devices is... certainly strange... :?

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Sun Feb 10, 2019 8:11 pm
by Wonks
It's certainly a hard one to solve or point a finger at the probable cause without being there.

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Sun Feb 10, 2019 8:24 pm
by CS70
Which pan law are you working with?

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Sun Feb 10, 2019 8:51 pm
by Hugh Robjohns
If you're getting the same problem with different DAWs then I think it would be worth checking the software mixer/routing settings for the Focusrite interface as a priority. Can you test with a different brand of interface?

H

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Sun Feb 10, 2019 9:29 pm
by Cosmic Audio
Thanks Hugh - yes, I’m getting the same results using a Presonus StudioLive series III, or no interface at all and using the built in audio in the Mac with headphones plugged directly in.

So I’ve completely ruled out ears, monitors, interface, monitor controller, cabling - in fact anything outside of the computer!

By using the external mixer I have determined that both Logic Pro and Studio One on my system are putting out identical signals in both the left and right channels when the channel pan is in the centre on the DAW, but very different signals when that same signal is panned hard left or right, on two different computers, with two different (or no) interfaces.

I’ve been doing this audio thing since before issue 1 of SOS back in the 80s, but this has really got me stumped!! I’ll see if I can reliably replicate it in a video over the next few days and show you all exactly what’s happening.

Thanks for all the thoughts and replies so far everyone!

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Sun Feb 10, 2019 10:01 pm
by Hugh Robjohns
A simple polarity inverted null test will reveal if the pan control really is introducing some frequency response error. Just re-record the panned-left/right outputs from a recorded noise track, time align, flip polarity and listen. You should see a null of well over 100dB easily, and each individual panned track should also null with the panned-central version too, although you'll have to adjust the levels to compensate for the pan-law of course.

While its entirely possible for there to be a coding cockup, I'm struggling to see how the pan control would introduce a tonal change. The most likely reason is that somehow there's a summing of original and processed (panned) signals resulting in some comb-filtering effect. It could be a routing issue in the DAW, but the same coding cockup isnt
Ilely in differen DAWs. Likewise, its not likely in different interfaces either. The common factor is the Mac's drivers.

Can you detail the precise versions of DAW and OS you're using? It might help others to compare their systems and findings.

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Sun Feb 10, 2019 10:48 pm
by desmond
While I didn't do a null test, I'm pretty confident that in my quick tests, Logic was outputting nothing significantly different on the left or the right when the noise source was panned appropriately, so I'm sure Logic (and other DAWs) are outputting audio correctly from it's main mix output.

How do you have the audio interface selected in Logic? is Logic's output interface set directly to your audio hardware, or is it set to "System", and then your System output set to your audio hardware? (this does make a difference).

It's possible you have some kind of system setting, or app, that's affecting the audio output by the system, and this setting persists on your other computers, maybe.

However, the fact you say you see the same thing on different audio hardware suggests that it can't be that hardware, or routing issues in the hardware/mix setup, so it has me a bit perplexed. It would be interesting for you to record an audio file showing the differences, and playing it back on a completely independent system (eg, making a CD, and playing it on your hifi system), or uploading the audio file here for us to have a look at on our systems...

If you have other outputs available on your system, try routing to those, and seeing whether the same issue affects the other pairs of outputs too...

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Mon Feb 11, 2019 6:19 pm
by Matt Houghton
desmond wrote:How do you have the audio interface selected in Logic? is Logic's output interface set directly to your audio hardware, or is it set to "System", and then your System output set to your audio hardware? (this does make a difference).

It's possible you have some kind of system setting, or app, that's affecting the audio output by the system, and this setting persists on your other computers, maybe.

That was going to be my suggestion...

A few years back (maybe 3-4?), on a different MacBook Pro on an earlier version of MacOS (I think maybe it was Mavericks, updated from an earlier version, rather than installed directly... I can't recall) I had a strange issue with the system sound whereby the OS kept defaulting to a slightly off-centre stereo balance — it literally put the balance slider in the System Prefs/Sound settings window in the wrong place!

It drove me insane for a week or two until I discovered what was causing it. Then I found that I could manually change the setting, but it kept defaulting back to off-centre whenever I rebooted. IIRC, this, and a number of other problems not relating to audio ( such as the ethernet networking failing when waking from sleep) were only 'solved' by creating a new profile on the machine and using that.

It might not be related to this problem... but worth checking. Also worth noting that the OS can store different balance settings for different interfaces.

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Mon Feb 11, 2019 10:14 pm
by desmond
Matt Houghton wrote:A few years back (maybe 3-4?), on a different MacBook Pro on an earlier version of MacOS (I think maybe it was Mavericks, updated from an earlier version, rather than installed directly... I can't recall) I had a strange issue with the system sound whereby the OS kept defaulting to a slightly off-centre stereo balance — it literally put the balance slider in the System Prefs/Sound settings window in the wrong place!

Yep, I've had that one more than once. Annoying. I don't think I've had it for a while, but it's one of those very intermittent things...

Matt Houghton wrote:It drove me insane for a week or two until I discovered what was causing it.

What *was* causing it?

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Tue Feb 12, 2019 3:22 pm
by Matt Houghton
desmond wrote:

Matt Houghton wrote:It drove me insane for a week or two until I discovered what was causing it.

What *was* causing it?

No, I just meant, "until I figured out that the OSX system sound panner kept snapping back to the wrong default position!" I have no idea why it was actually doing that. As with various other things, it seems to have been a glitch in the profile — as I say, it and other issues (losing ethernet connectivity on waking from sleep; losing network 'locations' info etc) were solved simply be creating a clean user profile. I had a lot of such issues around Mavericks, which was not a clean install but an 'upgrade' on what came before.

I love Macs; they just work ;)

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Tue Feb 12, 2019 3:32 pm
by CS70
desmond wrote:What *was* causing it?

The most likely cause is some issue in how the hardware talks to the computer. You could see if there's any firmware update for the audio unit. Macs also have this system management controller that apparently need the occasional reset when things don't work..

Re: Left channel and right channel of DAW sound VERY different!

PostPosted: Tue Feb 12, 2019 4:17 pm
by Matt Houghton
CS70 wrote:
desmond wrote:What *was* causing it?

The most likely cause is some issue in how the hardware talks to the computer. You could see if there's any firmware update for the audio unit. Macs also have this system management controller that apparently need the occasional reset when things don't work..

Yeah, I went through all that. It didn't work. The only thing that sorted it was creating a fresh profile. And bizarrely then switching back to the original profile got the ethernet working again (but not the panning). Until the machine went to sleep. Not a problem for me now... that was my previous machine, and the issue was very definitely a glitch in the OS or profile, not in any external hardware (it occurreed with the built in speakers and the headphone out.)

Just posting the experience here in case it helps the OP... i may or may not be the same issue.