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Stereo input, mono output
Old 20th September 2012
Here for the gear
๐ŸŽง 5 years
Stereo input, mono output

I have a laptop connected using a balanced 3.5mm line jack to a 1/4 inch line jack to a mixer(VLZ3-3204)'s line in. My speakers are placed in both left and right main outputs. However, sometimes, when I play songs out of my laptop, the sound produced lacks some parts of the song. Sometimes, the vocals would be lost, other times the instruments. I heard that this problem may be due to playing a stereo music out of a mono source, as one of the stereo track may be lost. However, I think that my connections are stereo, or are the actually mono? Is there any way I can fix this?
Old 20th September 2012
Lives for gear
NeoHippy's Avatar
๐ŸŽง 5 years
i guess the mixer has a balanced jack input....that means it reverses the phase from either the hot pin or the cold...

if you send a stereo signal into it (3.5mm jack from laptop isnt balanced, but stereo), the mixer substracts the left from the right signal meaning the mid signal is lost...

if the vocals are mixed just in the middle they will be lost or much more quite...the instrments in the middle will be lost too...

you need a 3.5 mm jack to 2x 1/4 inch jack mono....

something like this: Google-Ergebnis fรผr http://www.musikdiscount24.de/images/articles/3ceafd51aaa844cad018cba1e1b02509_5.jpg

and then you need to use 2 channels of your mixer where you hook up the 1/4 to.
pan one channel hard right, the other one hard left...

that should do the trick

Old 20th September 2012
Gear Nut
๐ŸŽง 5 years
NeoHippy is correct, just wanted to add that even an inexpensive usb interface will sound waaaaay better than your laptop's output (obviously pretty important when trying to track/mix accurately). Good luck!
Old 21st September 2012
Here for the gear
๐ŸŽง 5 years
As for the USB interface, there is actually a USB wire connected to the mixer. Would it be better for me to use the USB port rather than a 3.5 wire? Would that solve the problem?
Old 21st September 2012
Here for the gear
๐ŸŽง 5 years
As for the 3.5mm to 2 mono TRS wire, could anyone provide me with a diagram on the internal soldering? I do not possess any of those, so I figured that I might solder it myself. Thanks.
Old 21st September 2012
Here for the gear
๐ŸŽง 5 years
Can someone explain to me, but if I was using a mono wire all along, why can most of my sounds work perfectly? I played about 10 songs for the entire event, yet only that one track has this problem. I am quite certain that most of the songs are in stereo, so shouldn't this problem occur to most of the songs?
Old 21st September 2012 | Show parent
Lives for gear
Lotus 7's Avatar
1 Review written
๐ŸŽง 10 years
Originally Posted by Arondite โžก๏ธ
As for the 3.5mm to 2 mono TRS wire, could anyone provide me with a diagram on the internal soldering? I do not possess any of those, so I figured that I might solder it myself. Thanks.
Cables that will connect a 3.5 mm stereo output to (2) 1/4 inch TS inputs are commercially available, and are inexpensive. They are called "stereo to mono "Breakout Cables". You can also easily build your own.

The 3.5 mm stereo "Ring" carries the right channel and the 3.5 mm "Tip" carries the left channel.

As far as the quality of the audio output available on a typical home computer or laptop, the correct answer is that it can vary widely. Although most home and laptop computers use decent 16 bit DACs the amount of noise present can vary dramatically with the particular computer. Some home computer motherboards have poor designs that allow some digital noise to get into the audio signal. Some have poor analog amplifiers driving the 3.5 mm "phone" output jack.

Having said that, the general trend is to include much better 3.5 mm outputs. Some of them are actually quite good. The outputs on the current Apple MacBook Pros are actually excellent and have good converters, low distortion and very low noise. It would be hard for most people to notice any difference between that output and the output from an external, high-quality DAC.

It's impossible to generalise and say "All internal computer audio outputs are no good" because it simply is not true in many cases. You have to listen yourself and decide if the signal quality is good enough for your use. Is an external USB driven DAC better? "Probably." Can you actually hear the difference? "It depends, maybe, but often probably not."

If you have been using a simple 3.5 mm to 1/4 inch TRS cable going to a single balanced input you have been hearing a mono signal that is the difference (rather than the mono sum) of the two stereo channels. How that sounds and what it includes depends entirely on how the signal was mixed and the phase relationships between the two stereo channels. It's obviously not correct. If a vocal is mixed to the exact center, it will be canceled out.

I've drawn a schematic of the 3.5 mm to 1/4 inch breakout cable.
3.5 mm stereo to 1/4 inch mono Breakout Cable:
Attached Thumbnails
Stereo input, mono output-breakout-cable.jpg  
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