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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: Dede2002 on June 11, 2007, 01:48:18 PM

Title: Unmatched Left and Right Channels
Post by: Dede2002 on June 11, 2007, 01:48:18 PM
Hi,

All of a sudden, my R-09 has decided to run the Left channel hotter, much hotter than the Right one. As far as I can see, there are two options:

1- I can increase the volume on the Right channel to match the other and them proceed to any editing I may need to do and normalize.

2- I can decrease volume on Left channel, perform editing and normalize the whoel thing.

Is there any diference in sound quality between those options or not?

Thanks in advance ;D
Title: Re: Unmatched Left and Right Channels
Post by: Dede2002 on June 11, 2007, 02:17:17 PM
Hi again,

I've failed to mention the weirdest thing. Please take a look at the wavefile.There's a huge diference between Right and Left. Well, there's no audible diference in sound volume when you actually listen to the file. ??? :-\
Title: Re: Unmatched Left and Right Channels
Post by: Dede2002 on June 11, 2007, 07:38:43 PM
Well, considering the fact that so far I got no replies, I'll perform this task myself. Regarding the last post, my bad! Of course both channels were sounding even: the problem is my headphone, which was working perfectly till yesterday. Right now, the left channel sounds like crap. I run some tests with other tracks and the problem persists. :P
Anyway, my original question remains the same. Thanks in advance for any help. ;)
Title: Re: Unmatched Left and Right Channels
Post by: stantheman1976 on June 11, 2007, 09:48:20 PM
Looks like there is little to no clipping thankfully.  I don't know what software you are using, but you can try mixing the channels together.  You may want to have stereo separation though.  In that case take the lower channel and match the higher.
Title: Re: Unmatched Left and Right Channels
Post by: Dede2002 on June 11, 2007, 10:33:03 PM
Looks like there is little to no clipping thankfully.  I don't know what software you are using, but you can try mixing the channels together.  You may want to have stereo separation though.  In that case take the lower channel and match the higher.

Thanks a lot for your help ;). Actually, there's no clipping. I just don't know what's going on with my R-09. The low volume channel peaks at around 12bd to 6db. Since it's a 24 bit recording, I guess I'll be fine raising the level, don't you think?
T+
Title: Re: Unmatched Left and Right Channels
Post by: stantheman1976 on June 11, 2007, 11:59:16 PM
I usually use hard limiting and peak at -3dB.  I try not to go too much, only boosting about 6dB or so.  In your case if you mix the two channels equally this might bring the whole thing to a good level.
Title: Re: Unmatched Left and Right Channels
Post by: rustoleum on June 12, 2007, 11:03:46 AM
the average human ear doesn't perceive a difference in sound levels until the difference exceeds roughly 3 db.  If your channels are within 3db of each other, I wouldn't touch them since most people will just perceive them to be at the same volume level.
Title: Re: Unmatched Left and Right Channels
Post by: terrapinj on June 12, 2007, 02:36:13 PM
id be more concerned with why you are getting such uneven channels? have you always got output like this ie mics are way off? maybe time for new batteries in the BatBox?
Title: Re: Unmatched Left and Right Channels
Post by: Dede2002 on June 12, 2007, 02:48:18 PM
id be more concerned with why you are getting such uneven channels? have you always got output like this ie mics are way off? maybe time for new batteries in the BatBox?

No, I haven't. This is a new thing. The mics are OK. I know that because I run a few tests with diferent mics and the problem persists ( using both Line In and/or Mic input). I'll check my BB batteries. Thanks for the tip. ;)
Title: Re: Unmatched Left and Right Channels
Post by: Dede2002 on June 16, 2007, 11:02:26 AM
Late to the thread so this may be moot.  In my experience as long as you don't go too far with pumping up the levels, you should be good.  Blending the two will loose your stereo effect I'm pretty sure.  If you boost much beyound 3-4db, or if your pre is a little noisy to start with, be prepaired to experiment with some noise reduction if you find the elevated noise floor too noticeable.  Not sure your application has this capability.  In any case, it may help or at least not hurt... if you first convert the bit rate from 16 to 32bit.  At least this is what I do.

HTH

Thanks a lot O-Canis. The final corrected file came out OK. Sounds fine. I always tape using the 24 bit/48.000 option on the R-09 and I've been told that, in this case, Noise Floor shouldn't be an issue.
 Anyway, I always hear about the Noise Floor and I know what it is. That's a complete novice question: what's the sound of noise floor? Can you describe it? It' like s a background noise? Is it like distortion?
Title: Re: Unmatched Left and Right Channels
Post by: gratefulphish on June 19, 2007, 11:36:54 PM
The noise floor sounds like hissing.  You really need to get to the root of why the channels are off.  Try all new batteries, swap cables and mics, and see if anything changes.  Otherwise, might need to get it checked out.  With the show you have, you can try normalizing each channel separately, and see what happens.  I have done this once or twice, in odd, off center taping setups, where one side came out significantly hotter than the other.
Title: Re: Unmatched Left and Right Channels
Post by: Dede2002 on June 25, 2007, 08:48:39 AM
The noise floor sounds like hissing.  You really need to get to the root of why the channels are off.  Try all new batteries, swap cables and mics, and see if anything changes.  Otherwise, might need to get it checked out.  With the show you have, you can try normalizing each channel separately, and see what happens.  I have done this once or twice, in odd, off center taping setups, where one side came out significantly hotter than the other.


Thanks a lot for the info. I'm working on the causes of the problem.
Title: Re: Unmatched Left and Right Channels
Post by: anr on October 20, 2007, 01:48:05 PM
I process/master recordings my mate does on an Edirol RO9 and I always know I have to adjust one channel by 2.76dB straight away.  It's a constant error and sounds/looks very similar to yours.  I checked it with various mics and batt boxes and it's the same, so concluded it was a fault on the RO9.  The only thing I suggested to him was to drop the rec level so the higher channel doesn't clip.  Interesting that someone has the same problem. 
Title: Re: Unmatched Left and Right Channels
Post by: Dede2002 on November 10, 2007, 06:58:24 PM
I process/master recordings my mate does on an Edirol RO9 and I always know I have to adjust one channel by 2.76dB straight away.  It's a constant error and sounds/looks very similar to yours.  I checked it with various mics and batt boxes and it's the same, so concluded it was a fault on the RO9.  The only thing I suggested to him was to drop the rec level so the higher channel doesn't clip.  Interesting that someone has the same problem. 

Well, it's good to know that I'm not alone on this one.
Thanks for letting me know ;)