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[Randall Cook]

It's bearable, but I'd prefer it to be better... Playing music from my computer or iPod through my PA sounds good, but sometimes it's lacking.  The signal is split left/right out of the computer/iPod into two separate channels.  From there, some songs lose clarity in some areas (sometimes vocals, sometimes guitar,...).  Playing the same song from the same iPod in my car or home stereo sounds normal, as would be expected since that's what it was designed for.  My PA is run tri-amped in mono, so the left/right is getting mixed together before it leaves the mixer.  I've tried plugging the left/right into one of the stereo channels of the mixer (GL2800), I've tried separate channels, I've tried panning at the channels, etc.
What is happening?
Is there something I can do to correct this?
I feel I'm missing something obvious on this, but I'm lost.
Thank you!

[Chuck Simon]

It's hard to come up with an answer from what info you have supplied, but this could be your soution:

http://whirlwindusa.com/catalog/black-boxes-effects-and-dis/direct-boxes/pcdi

It allows you to combine the stereo outputs from your source and connect into a single  channel with an XLR connector.

How is your "left/right is getting mixed together"?  Are you using the mono output on the board?  I hope you are not using a Y chord.

[Randall Cook]

All channels on my board are directed to subgroups, the subgroups are directed to one output.  I use the XLR output to my DSP and so on and so on...  mono output.
All other sources (live bands) sound superb.  Direct music input is acceptable and the patrons enjoy dancing to it... I just hear things better than most I guess.

Do the left signal and right signal of a stereo recording cancel each other at some points?  That's what I feel is happening, but not sure.  Could be something else.

[Chuck Simon]

Do the left signal and right signal of a stereo recording cancel each other at some points?

Yes, if the polarity is not the same for each channel, and believe it or not I have seen that with some of the cables people use with ipods and laptops!  I think we might be on to something!  Try reversing the polarity of one of the channels on your board and see if that helps.

Another thought, if you are using one sub group with the A&H board, you might be getting only half of the stereo signal.  For example, if you are using your stereo channels on the board and pan both of your channel inputs to group 1, you are only sending the left stereo signal to ouput.

[Mac Kerr]

It's hard to come up with an answer from what info you have supplied, but this could be your soution:

http://whirlwindusa.com/catalog/black-boxes-effects-and-dis/direct-boxes/pcdi

It allows you to combine the stereo outputs from your source and connect into a single  channel with an XLR connector.

How is your "left/right is getting mixed together"?  Are you using the mono output on the board?  I hope you are not using a Y chord.

No. He is already using 2 console channels. The problem is most likely a stereo signal that is not mono compatible. This was less common in the days of mono radio music stations, when record companies actually checked for mono compatibility before releasing a record, I doubt many of today's record producers are aware there is such a thing. This is a phase issue, not a polarity issue.

To combine well into mono, the 2 stereo channels have to have similar phase response between the signals in the left and right channels. If not there will be frequency response errors created by combining the 2 channels. This is a good reason to run your PA in stereo even if you mix in mono. Playback and effects often do not combine well to mono and are best used in stereo.

Mac

[Chuck Simon]

Mac, that is an excellant point, but we don't know for sure if it is a polarity issue until he tries reversing one of them.

[Mac Kerr]

It's bearable, but I'd prefer it to be better... Playing music from my computer or iPod through my PA sounds good, but sometimes it's lacking.

Mac, that is an excellant point, but we don't know for sure if it is a polarity issue until he tries reversing one of them.

I think we do. In his original post he says it is not always bad, and that even when it is lacking it is still OK. A polarity issue would have no bass at all, and the mids and highs would not sound good. If it is dependent on program material I don't see how it can be polarity.

Mac

[Chuck Simon]

I have a A&H board  and my stereo tracks always sound great through a mono system. I have never experienced a phase problem that I or anyone else has noticed.

[Randall Cook]

It's hard to come up with an answer from what info you have supplied, but this could be your soution:

http://whirlwindusa.com/catalog/black-boxes-effects-and-dis/direct-boxes/pcdi

It allows you to combine the stereo outputs from your source and connect into a single  channel with an XLR connector.

How is your "left/right is getting mixed together"?  Are you using the mono output on the board?  I hope you are not using a Y chord.

No. He is already using 2 console channels. The problem is most likely a stereo signal that is not mono compatible. This was less common in the days of mono radio music stations, when record companies actually checked for mono compatibility before releasing a record, I doubt many of today's record producers are aware there is such a thing. This is a phase issue, not a polarity issue.

To combine well into mono, the 2 stereo channels have to have similar phase response between the signals in the left and right channels. If not there will be frequency response errors created by combining the 2 channels. This is a good reason to run your PA in stereo even if you mix in mono. Playback and effects often do not combine well to mono and are best used in stereo.

Mac

Mac, I think you nailed it.  I was afraid of this only because I run "aux-fed" subs and want to keep returns to a minimum.  I only have 10 returns and sometimes I run wedges and in-ears (total=7 or .  So, I may need to upgrade my snake to add more returns.  I already have my DSP in my amp rack to keep returns to minimum.  I run "aux"fed channels to relevant subgroups and assign those "sub-only" groups to "C" and that is my sub output to the DSP input #2.  All other subgroups go to "L" & "C".  "L" is my hi/mid output to the DSP input #1.
It sounds great otherwise.  I guess going from my tri-amp mono system with aux fed to a stereo quad-amped with aux fed system will eat up a ton of returns!  WHEW!

So, is there anything I can do with the recorded music before I make the changes to go to stereo PA?  Probably not since it's in the recording.  Bummer.  Somebody skool these producerz!

[Mac Kerr]

I guess going from my tri-amp mono system with aux fed to a stereo quad-amped with aux fed system will eat up a ton of returns!  WHEW!

Well, 1 more return, and 1 more DSP channel anyway.

Mac

[Randall Cook]

Would something like this combine the stereo signals into mono properly? Whirlwind PCDI

[Dan Richardson]

Would something like this combine the stereo signals into mono properly? Whirlwind PCDI

Yes, it would, but you're already combining your channels properly.
It's just luck of the draw these days as to whether a given track will be mono compatible or not.
Some stereo processing done while mixing a track simply sounds bad when you mono it up.
Audition your tracks in mono, and only play the ones that don't suck.

[Randall Cook]

Well folks, I'll have to think on this one.  Either I switch over to stereo PA operation or leave it as-is and live with it.   

[Marsellus Fariss]

Well folks, I'll have to think on this one.  Either I switch over to stereo PA operation or leave it as-is and live with it.   

I encounter this problem frequently feeding stereo keyboards and samplers into mono monitor mixes. My working method is to start with one side in the wedge and ask the muso's if it's better or worse when I add in the other side of the stereo sample. You can likely do the same if your running both L and R of your playback into two separate channels on your console. Put up the left side and add the right and see if everything goes to shit on one of the problem songs. Don't think there's much you can do for these tracks. Maybe avoid using them for walk-in? Possible it might bite you in the ass if your doing a gig requiring specific playback of pre-prepared material. 

[Patrick Tracy]

I encounter this problem frequently feeding stereo keyboards and samplers into mono monitor mixes. My working method is to start with one side in the wedge and ask the muso's if it's better or worse when I add in the other side of the stereo sample. You can likely do the same if your running both L and R of your playback into two separate channels on your console. Put up the left side and add the right and see if everything goes to shit on one of the problem songs. Don't think there's much you can do for these tracks. Maybe avoid using them for walk-in? Possible it might bite you in the ass if your doing a gig requiring specific playback of pre-prepared material.

This is why I like to use pairs of mono channels for stereo inputs. If a stereo feed is going to be in mono wedges I like to alternate, left in mix 1, right in mix 2 and so on.

[Chris Davis]

Well folks, I'll have to think on this one.  Either I switch over to stereo PA operation or leave it as-is and live with it.   

Or yet another variation could be to just use one of the two stereo channels as the source into your mono system. 

So what is causing this?

Bad production technique may be causing some mono incompatibility, as Mac said.

Now, I might also suspect that the computer soundcard has something to do with this.

Many internal computer soundcards have el cheapo output devices that are not actually dedicated to or capable of delivering both left and right channels simultaneously.  This has caused documented problems with loudspeaker measurement systems.  So that might be a part of the root cause here too.  The solution for this would be to try a higher quality outboard soundcard.

I wouldn't initially suspect that the Ipod output driver might be causing this but who knows. 

Due to the fact that you are using an Ipod, that brings up the question of whether the file compression scheme - if any used- might be a part of the problem.  Same goes for the PC.

So you see there are many possible reasons but few solutions.

[Chuck Simon]

You might be right, Chris.  As I said, I never have experienced the problem when combining stereo tracks to a mono output, but I almost always use a CD player.

[Dennis Wiggins]

It's bearable, but I'd prefer it to be better... Playing music from my computer or iPod through my PA sounds good, but sometimes it's lacking.  The signal is split left/right out of the computer/iPod into two separate channels.  From there, some songs lose clarity in some areas (sometimes vocals, sometimes guitar,...).  Playing the same song from the same iPod in my car or home stereo sounds normal, as would be expected since that's what it was designed for.  My PA is run tri-amped in mono, so the left/right is getting mixed together before it leaves the mixer.  I've tried plugging the left/right into one of the stereo channels of the mixer (GL2800), I've tried separate channels, I've tried panning at the channels, etc.
What is happening?
Is there something I can do to correct this?
I feel I'm missing something obvious on this, but I'm lost.
Thank you!

Have you tried another stereo souce, such as a CD player?  That may reveal something.

BTW, make sure you use an orignal CD, not a 'burn' of an MP3.

-DW

[Steve Hurt]

Have you tried another stereo souce, such as a CD player?  That may reveal something.

BTW, make sure you use an orignal CD, not a 'burn' of an MP3.

-DW

If they are using mp3 or other compressed files, then I'd agree that listening to CD's will help
Compressed files make audio less clear.  Especially thru loud PA's

Other contributing factors
- Stereo sounds better.  (Although, in some acoustic spaces, mono still works better)
It's the way we hear and we prefer it.  Close one eye and you lose depth perception.  Same with listening in mono.

Stereo recordings that are not optimized for mono compatibility during mixing can be really bad in mono and sound fine in stereo.
Just depends on the mix.

It seems worst on CD's that are intentionally mastered to the point of distortion to make the CD "louder"

[alan hamilton]

I've tried panning at the channels, etc.
What is happening?
Is there something I can do to correct this?
I feel I'm missing something obvious on this, but I'm lost.
Thank you!

What are you using for cable and adapters from your Ipod or computer into the board? 1/8th to RCA to ? ??

While Mac's theory is certainly possible, either you're extremely picky, unlucky with track choice, or else something else is going on because it shouldn't be that frequent you have issues with a recording that isn't mono-friendly.

People run stereo trax into mono PA's often enough without ever having your issue that I wouldn't overlook other possibilities.

At first I thought I was going to read that you were coming 1/8" out to RCA and then Ying those together at a single input. ...And I was expecting that "Y" to "Y" down to a 1/4" Male TRS... Which would then give you the problem you describe because you'd be feeding the left + to the tip of the TRS and the R + to the ring of the TRS (which the board would expect to be pin 3 of a balanced signal).

[Tracy Garner]

This is why I like to use pairs of mono channels for stereo inputs. If a stereo feed is going to be in mono wedges I like to alternate, left in mix 1, right in mix 2 and so on.

My laptop audio software has a MONO/STEREO selection on the output. it still feeds both channels but does a good job of combining left/right in the proper phase.

Often when using two channels of the console, I always do a 9 oclock on the left channel and a 3 oclock on the right channel - even when the final output is MONO.

[Patrick Tracy]

My laptop audio software has a MONO/STEREO selection on the output. it still feeds both channels but does a good job of combining left/right in the proper phase.

Combining a stereo signal into a mono one without changing phase is a trivial task. It would be surprising if summing caused phase issues that didn't exist in the source material.

Often when using two channels of the console, I always do a 9 oclock on the left channel and a 3 oclock on the right channel - even when the final output is MONO.

I don't see how that is any different from panning them hard or center if they get summed anyway, unless you're using one channel of a stereo output for your mono feed.

[Tracy Garner]

Combining a stereo signal into a mono one without changing phase is a trivial task. It would be surprising if summing caused phase issues that didn't exist in the source material.

I don't see how that is any different from panning them hard or center if they get summed anyway, unless you're using one channel of a stereo output for your mono feed.

Either way works. There are a lot of right answers for this post.

Sometimes, we end up recording stereo or feeding video in stereo while the speaker setup is still MONO.

Sometimes, I will use a DI combiner from the DJ mixer or laptop and use only one channel on the console.

Sometimes a DJ doesn't have a lot of output control from their mixer or laptop so we end up summing the 2 channels on his behalf from the console even if the whole system is setup in stereo. OR...There are a few infamous DJs that actually use an electronic crossover in their setup and will send you channel 1 as low and channel 2 as high...

Sometimes speakers are setup in a venue (mostly dance) in a way that a hard pan is too much pan in stereo. At the same time full mono is less than desirable.

[Randall Cook]

Honestly, the majority of the tracks sound good, but there are enough that make me want to do something about it.
I generally use and iPod.  All of my music is at Apple lossless/high rates, so it's all good quality from that perspective.
Since most tracks sound good, it's definitely song specific; not gear issues.
I think I'll deal with it for know.  I may try stereo operation in the future, but some venues and outdoor events are too wide for hard-panned stereo playback since I don't use a center fill at this time.
Thank you all for your responses!

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