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Playing an mp3 track through an audio interface via line-in

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Playing an mp3 track through an audio interface via line-in

Postby Miket123 » Sun Jan 10, 2021 7:17 pm

Hi all

I'm new to this forum and this technology, so please be gentle.

I have tried searching here on this forum and on the internet generally, but no answers yet.

I have an Alesis Multimix 4 in a small, very amateur home studio and I have tried to play an audio track via line in so that I can sing over it. When I do this, it sounds like the player is underwater and is clearly unusable.
I have tried connecting my other MacBook pro and also an iPod touch to play the tracks, but no success.
I am connecting using a 3.5mm to 6.25mm jack lead

I just assumed that line in would allow any medium to be connected and play through the audio interface, but perhaps this is impossible.

Any ideas would be really helpful

many thanks
Mike
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Re: Playing an mp3 track through an audio interface via line-in

Postby Murray B » Sun Jan 10, 2021 8:03 pm

Does the cable you are using split the signal into left and right - so you have two mono 6.25mm jacks?

If it doesn't this probably isn't helping as you'll be putting a stereo signal into a mono input.
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Re: Playing an mp3 track through an audio interface via line-in

Postby Sam Spoons » Sun Jan 10, 2021 8:18 pm

This is probably the problem but the manual nor the specs for the Alesis say if the line inputs are balanced or not. For clarity is the lead you are using one of these? :-

Image

What you need is one of these :-

Image
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Re: Playing an mp3 track through an audio interface via line-in

Postby Miket123 » Sun Jan 10, 2021 8:33 pm

Thanks for the replies - I have only been using one cable and I think it's a TRS like the bottom of the two you posted. I thought these were balanced cables and better than the unbalanced - BTW, I'm saying these words without any real knowledge of what this means.
I didn't consider it might be an issue of stereo output into mono input

Here's my lead
https://drive.google.com/file/d/1SKcyAUqtKmwIWzbzPaTDmP8jhPUvAoNh/view?usp=sharing

I hadn't really thought about a twin 6.25 cable into the Alesis and a 3.5mm into the iPod touch or Mac. I will have to purchase one of these and try it out

many thanks again
Cheers
Mike
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Re: Playing an mp3 track through an audio interface via line-in

Postby Murray B » Sun Jan 10, 2021 8:58 pm

I think we have a diagnosis :-)

Should be fine if you get yourself a cable that splits the signal into left and right - use this in inputs 3+4

Ps Nice work with the pics Sam - being new to posting I haven't tried this yet.
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Re: Playing an mp3 track through an audio interface via line-in

Postby Luke W » Sun Jan 10, 2021 9:38 pm

Yep, sounds like the classic unbalanced stereo source feeding a balanced mono input problem. A cable like Murray and Sam have suggested will do the trick. :thumbup:
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Re: Playing an mp3 track through an audio interface via line-in

Postby Hugh Robjohns » Sun Jan 10, 2021 10:09 pm

Miket123 wrote:I have an Alesis Multimix 4 in a small, very amateur home studio and I have tried to play an audio track via line in so that I can sing over it. When I do this, it sounds like the player is underwater and is clearly unusable.

This is an absolutely classic description of what happens when connecting an unbalanced stereo source to a balanced mono input, with a data-reduced (mp3) signal!

I am connecting using a 3.5mm to 6.25mm jack lead

Yes, that fits. You actually need a 3.5mm TRS to dual 6.25mm TS jack cable, and your stereo sorce needs to feed two input channels of your Alesis, you capture the left and righ channels separately.

edit: ...and I see several others here have already recognised the situation and offered the same advice. ;-)
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