Dj Dunc Posted January 1, 2007 Share Posted January 1, 2007 Yaaay first problem in the new year :) Ok the problem is this : Samson mpl2242 mixer, stereo in from computer into a mono channel seems easy enough, but then as soon as I patch it in and oik up a fader, hey presto, a fantastic bathroom echo comes in, and I cant remove it no matter what I do. it is fine when I use a stereo channel, but as it is a stereo feed on a single jack, then im kinda bummed as it outputs it as only right or left to the speakers :) ideas people :** laughs out loud **: dunc Link to comment Share on other sites More sharing options...
Bobbsy Posted January 1, 2007 Share Posted January 1, 2007 Try a different stereo source and see what happens. Some stereo sources have huge phase problems when they're summed to mono. Happy New Year! Bob Link to comment Share on other sites More sharing options...
Dj Dunc Posted January 1, 2007 Author Share Posted January 1, 2007 Gaahh. it does the same thing with my mp3 player. and when I try panning either item, I lose most of the sound if I pan it to left on all mono channels. why does this sound so much like, my mixer is nackered??? Link to comment Share on other sites More sharing options...
MarkPAman Posted January 1, 2007 Share Posted January 1, 2007 I think that once you get the leads you need to plug this in properly you'll find all is OK. (If I understand you correctly) Happy new year! :) Link to comment Share on other sites More sharing options...
bigglesuk Posted January 1, 2007 Share Posted January 1, 2007 The mixer is expecting a balanced signal using the cables you mention. It's trying to sum together the left and right signals to make one rather than the positive and negative. Why it doesn't do that on a stereo channel as well I don't know. Link to comment Share on other sites More sharing options...
Bobbsy Posted January 1, 2007 Share Posted January 1, 2007 A "one legged" balanced signal tends to sound tinny, not echoey. My theory still has to be a phase problem in the summing, perhaps with a wrongly wired cable or something. Bob Link to comment Share on other sites More sharing options...
mackerr Posted January 1, 2007 Share Posted January 1, 2007 Your computer is sending unbalanced left channel on tip and sleeve, unbalanced right channel on ring and sleeve. The mono input is expecting tip and ring to have the same signal, but opposite polarity. When you plug your stereo signal into the mono input the parts of the signal that are the same, but not opposite polarity, get cancelled out, which is most of the signal. What is left are the signals that are greatly different in left and right, mostly reverb. Buy the correct adaptor at your local electronics store and you'll be fine. Mac Link to comment Share on other sites More sharing options...
Tomo Posted January 1, 2007 Share Posted January 1, 2007 The correct adaptor is a Y-cable - one output for Left, another for Right. I can't remember the pinout for unbalanced into balanced without a DI, but I think it's Common on Pin 2, signal on Pin 3, Pin 1 Not Connected - someone please correct me if I'm wrong! Link to comment Share on other sites More sharing options...
Bobbsy Posted January 1, 2007 Share Posted January 1, 2007 Your computer is sending unbalanced left channel on tip and sleeve, unbalanced right channel on ring and sleeve. The mono input is expecting tip and ring to have the same signal, but opposite polarity. When you plug your stereo signal into the mono input the parts of the signal that are the same, but not opposite polarity, get cancelled out, which is most of the signal. What is left are the signals that are greatly different in left and right, mostly reverb. Buy the correct adaptor at your local electronics store and you'll be fine. That's what I was trying to say with my comments about a phase issue in the summing to mono...but last night my brain was taking exception to my experiment with using my body as a human cocktail shaker. Bob Link to comment Share on other sites More sharing options...
timtheenchanteruk Posted January 1, 2007 Share Posted January 1, 2007 the answers so far are correct, to my knowledge,but to why it doesn't do it with the stereo channels, on this desk (just checked) only the mono channels are balanced, the stereo channels are all unbalanced, so its not getting the phased effect, just one side of the stereo. the pin out for this desk is tip +, ring -, sleeve shield, for the unbalanced, obviously, tip + sleeve - hope it helps, PS if you need a manual, let me know I have the manual for my desk here, I can scan it for you. Link to comment Share on other sites More sharing options...
James Posted January 1, 2007 Share Posted January 1, 2007 the pin out for this desk is tip +, ring -, sleeve shield, for the unbalanced, obviously, tip + sleeve - That is incredibly un obvious. I've never seen a desk connected like that before. In my experience desks tend to be... BALANCED Tip + Ring - Sleve (Shield) UNBALANCEDTip (Signal)Sleve (Shield) Link to comment Share on other sites More sharing options...
BlueShift Posted January 2, 2007 Share Posted January 2, 2007 balanced jacks are wired as tomo has said. a balanced XLR is wired as the name (an acronym) implies: 1:screen, 2:line, 3:return. IE 1:gnd, 2:+, 3- sending an unbalanced source into a balanced input should be done by wiring singal to + (tip or pin 2) and connecting screen to screen AND - (pin 1 and 3 or sleeve and ring). this ensures any induced signal on the balancing line is discharged to ground and doesnt inadvertantly removed from your signal. Link to comment Share on other sites More sharing options...
MarkPAman Posted January 2, 2007 Share Posted January 2, 2007 a balanced XLR ..........the name (an acronym) Oh no it isn't :biggrin: Link to comment Share on other sites More sharing options...
BlueShift Posted January 2, 2007 Share Posted January 2, 2007 touche nonetheless the screen line return thing is handy in remembering the pinout for an XLR. Link to comment Share on other sites More sharing options...
PoppaDom Posted January 2, 2007 Share Posted January 2, 2007 The correct adaptor is a Y-cable - one output for Left, another for Right. Not being pedantic but this isn't a Y-Cable. A Y cable defines a cable that literally is a Y and splits the signal to two outputs/inputs. As this cable outputs a different signal on each output surely this cable is a X-Y cable! Poppadom Link to comment Share on other sites More sharing options...
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