Reply
 
Thread Tools Display Modes
  #1   Report Post  
Posted to rec.audio.pro
Ludwig77 Ludwig77 is offline
external usenet poster
 
Posts: 62
Default Routing a stereo out to a mono input.

I played a gig using my laptop to play backtrack MP3s.

The MP3s were recorded in stereo. I was running out my laptop's
headphone out jack via a cable that converts 1/8" to 1/4'. I ran that
to a direct box and then to the board.

It seemed that some instruments were missing. Would I be right to
theorize that I would have been losing one of the two speaker's in the
stereo field via this routing?

If so, how would I be able to ensure that both stereo tracks would
have been routed to the mono signal?
  #2   Report Post  
Posted to rec.audio.pro
jakdedert jakdedert is offline
external usenet poster
 
Posts: 672
Default Routing a stereo out to a mono input.

Ludwig77 wrote:
I played a gig using my laptop to play backtrack MP3s.

The MP3s were recorded in stereo. I was running out my laptop's
headphone out jack via a cable that converts 1/8" to 1/4'. I ran that
to a direct box and then to the board.

It seemed that some instruments were missing. Would I be right to
theorize that I would have been losing one of the two speaker's in the
stereo field via this routing?

If so, how would I be able to ensure that both stereo tracks would
have been routed to the mono signal?


One of two things could have been happening: You used a mono plug and
indeed lost one side of the stereo signal...or you used a stereo plug
and combined the left/right signals out of phase. Either could account
for your missing instruments.

The proper way (one at least) would be to use two DIs, or a stereo DI.
Lots of stereo 'av' DIs will properly sum the l/r channels and then
output to one balanced out. Otherwise, two DI's--with the proper cables
to split l/r--would work (into two channels of the mixer). I've used
this one very successfully:
http://www.directproaudio.com/product.cfm?directid=61283 but it's
pretty pricey.

Otherwise, you could use a summing network ahead of your single DI to
combine the l/r channels in a fashion that won't upset the stereo output
of your lappie. Many (most) don't like l/r to be just connected
together without some resistance to isolate them. Distortion is the
usual result. A couple of 1k ohm--1/8 watt resistors is probably enough
to make your output happy. Connect one end of each in series with the
left and right outputs and tie the other two ends together. Where
they're tied together is your summed mono out. You can build that into
the housing of a 1/4" plug....

jak
  #3   Report Post  
Posted to rec.audio.pro
Mike Rivers Mike Rivers is offline
external usenet poster
 
Posts: 8,744
Default Routing a stereo out to a mono input.

Ludwig77 wrote:
I played a gig using my laptop to play backtrack MP3s.

The MP3s were recorded in stereo. I was running out my laptop's
headphone out jack via a cable that converts 1/8" to 1/4'. I ran that
to a direct box and then to the board.

It seemed that some instruments were missing. Would I be right to
theorize that I would have been losing one of the two speaker's in the
stereo field via this routing?


That's certainly a valid theory. You need to figure out how the cable
you have
is wired. Most likely it has the tip and ring contacts (left and right
channels) of the
mini plug connected in parallel and wired to the tip of the 1/4" plug.
That should work.
But if it's a "balanced-to-unbalanced" cable, the two plugs would be
connected
tip-to-tip and the ring of the mini plug would be connected to the
sleeve (ground).
That would effectively short out one channel.

If you have an ohm meter or other continuity tester, you could check out
your
cable. Or you could make a test recording on one channel, then the other
channel,
and play it back to verify that you get both channels.

Another possibility is that some MP3 encoders do strange things with the
phase
relationship between the two channels which could make a hole in the
middle of
the stereo image and, in mono, make some things drop out.

Does your mixer have line inputs? If so, that makes it easy to
experiment - just connect
the headphone output directly to the line input, using the appropriate
adapter. If, during
your shows, the mixer is located at some distance from your MP3 player,
then using a
DI is a good idea for making that long cable run, but if it's within
reach, you can eliminate
the DI. That won't solve your missing instruments problem, but it will
simplify your
hookup and you won't sacrafice any sound quality.


--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)
  #4   Report Post  
Posted to rec.audio.pro
Ludwig77 Ludwig77 is offline
external usenet poster
 
Posts: 62
Default Routing a stereo out to a mono input.

On Mar 29, 1:53*am, jakdedert wrote:
Ludwig77 wrote:
I played a gig using my laptop to play backtrack MP3s.


The MP3s were recorded in stereo. I was running out my laptop's
headphone out jack via a cable that converts 1/8" to 1/4'. I ran that
to a direct box and then to the board.


It seemed that some instruments were missing. Would I be right to
theorize that I would have been losing one of the two speaker's in the
stereo field via this routing?


If so, how would I be able to ensure that both stereo tracks would
have been routed to the mono signal?


One of two things could have been happening: You used a mono plug and
indeed lost one side of the stereo signal...or you used a stereo plug
and combined the left/right signals out of phase. *Either could account
for your missing instruments.


I was actually using a stereo cable 1/8" on laptop end to 1/4". The
1/4" side had a stereo adaptor. This end went into the DI box for XLR
conversion.

Since I first posted, I confirmed that I was only getting the right
speaker from the stereo field. Could I simply solve this problem by
using a 1/8" to 1/4" mono convertor? Would a mono convertor route both
speakers' mixes?
  #5   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Routing a stereo out to a mono input.

Ludwig77 wrote:
I played a gig using my laptop to play backtrack MP3s.

The MP3s were recorded in stereo. I was running out my laptop's
headphone out jack via a cable that converts 1/8" to 1/4'. I ran that
to a direct box and then to the board.

It seemed that some instruments were missing. Would I be right to
theorize that I would have been losing one of the two speaker's in the
stereo field via this routing?


Yes. One channel is tip, and goes to your output. The other channel is
ring, and goes to ground.

If so, how would I be able to ensure that both stereo tracks would
have been routed to the mono signal?


You can make an adaptor with a TRS plug, with T and R both wired through
1K resistors to the T of your 1/4" TS plug. I make a similar adaptor with
47 ohm resistors for my wife to listen to headphones, since she has only
one working ear.

Or, you can set it all to mono in software, which seems like the easiest
solution.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."


  #6   Report Post  
Posted to rec.audio.pro
[email protected] jwvm@umich.edu is offline
external usenet poster
 
Posts: 24
Default Routing a stereo out to a mono input.

On Mar 29, 8:49*am, Ludwig77 wrote:
On Mar 29, 1:53*am, jakdedert wrote:





Ludwig77 wrote:
I played a gig using my laptop to play backtrack MP3s.


The MP3s were recorded in stereo. I was running out my laptop's
headphone out jack via a cable that converts 1/8" to 1/4'. I ran that
to a direct box and then to the board.


It seemed that some instruments were missing. Would I be right to
theorize that I would have been losing one of the two speaker's in the
stereo field via this routing?


If so, how would I be able to ensure that both stereo tracks would
have been routed to the mono signal?


One of two things could have been happening: You used a mono plug and
indeed lost one side of the stereo signal...or you used a stereo plug
and combined the left/right signals out of phase. *Either could account
for your missing instruments.


I was actually using a stereo cable 1/8" on laptop end to 1/4". The
1/4" side had a stereo adaptor. This end went into the DI box for XLR
conversion.

Since I first posted, I confirmed that I was only getting the right
speaker from the stereo field. Could I simply solve this problem by
using a 1/8" to 1/4" mono convertor? Would a mono convertor route both
speakers' *mixes?


It really depends on what is inside the mono converter. As others have
suggested, you could sum the signals through a resistor. An
alternative would be to mix down the tracks to mono and use them
instead. You might find the second approach gives you more control
over the balance of different instruments by adjusting the channel
levels before mixing. It is a little surprising that the left channel
was missing since the tip is the left channel. If the DI were mono,
only the tip would be connected.
  #7   Report Post  
Posted to rec.audio.pro
Mike Rivers Mike Rivers is offline
external usenet poster
 
Posts: 8,744
Default Routing a stereo out to a mono input.

Ludwig77 wrote:

I was actually using a stereo cable 1/8" on laptop end to 1/4". The
1/4" side had a stereo adaptor. This end went into the DI box for XLR
conversion.


You really need to be clearer about your terminology. A "stereo adaptor"
is unclear. Does the 1/4" plug have three metal pieces, like a headphone
plug,
or two pieces like a guitar cable plug? If it's like a headphone plug,
you're still
only connecting one channel to the DI. Forget the bits about resistors. You
need to connect the two outputs of your MP3 player together and connect
THAT to the DI box.

Assuming you're in the US, go to your friendly local radio shack store
and buy,
or at least look at the following two parts:

Catalog #: 42-2545
http://www.radioshack.com/product/in...ductId=2103863
and
Catalog #: 42-2540
http://www.radioshack.com/product/in...ductId=2102972

Plug them together and you'll have what you need. You can get a longer
version
of the 1/8" plug to two RCA plugs cable.



--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)
Reply
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
mono wire into a stereo input genericaudioperson Pro Audio 12 December 8th 08 03:15 AM
Simple multi-channel mono input to PC over USB? [email protected] Pro Audio 0 June 19th 06 02:39 AM
Escort '97 - Can I add Stereo RCA input plugs to my factory stereo? David Car Audio 0 November 29th 04 09:46 PM
mono/stereo/dif.... Bob Pro Audio 0 October 5th 04 08:33 AM
Help! Mackie 1402-VLZ + Stereo Effects Routing? MikeTEACHR Pro Audio 7 September 3rd 04 02:33 AM


All times are GMT +1. The time now is 11:17 AM.

Powered by: vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AudioBanter.com.
The comments are property of their posters.
 

About Us

"It's about Audio and hi-fi"