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Laptop headphone out into Liquid Saffire 56

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Laptop headphone out into Liquid Saffire 56

Postby Sam the Scholar » Sun Oct 18, 2020 7:39 pm

The Liquid Saffire 56 routing is making my head hurt - googling the problem is also causing problems with lots of people agreeing the routing is painful.

I just need to plug an old laptop into the soundcard (via the headphone out), I have tried the line inputs, the mic inputs, the RCA inputs - through the line and mic inputs the sound is of poor quality and I can't get any signal through the RCA (probs routing)

This strikes me as a simple problem that I'm just not seeing / understanding.

I have a 3.5mm lead going to guitar jack (TRS) going from the old laptop headphone port, plugged into either a line input or an instrument input - both sound like it is underwater. I have also tried 3.5mm to XLR input on the soundcard - same problem.

I have a 3.5mm jack into RCA where I can't get any signal up

Any advice welcome,
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Re: Laptop headphone out into Liquid Saffire 56

Postby James Perrett » Sun Oct 18, 2020 8:29 pm

You need a 3.5mm TRS jack to 2 TS jack cable. The cable you are using at the moment will only let you hear the difference between the left and right channels if you plug it into a balanced input like those fitted to the Focusrite. If you are feeding it a mono signal you will hear nothing.
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Re: Laptop headphone out into Liquid Saffire 56

Postby Hugh Robjohns » Sun Oct 18, 2020 8:29 pm

Sam the Scholar wrote:I just need to plug an old laptop into the soundcard (via the headphone out), I have tried the line inputs, the mic inputs, the RCA inputs - through the line and mic inputs the sound is of poor quality and I can't get any signal through the RCA (probs routing)

The RCA connectors are for digital (S/PDIF) in and out, so it's not surprising you get nothing from an analogue headphone feed via that route!

The line inputs will work (and so will the mic inputs, although less appropriate) provided you use the correct kind of cable. You need a cable wired with a 3.5mm minijack at one end, and a pair of mono quarter-inch jack-plugs at the other, one for the left channel and one for the right.

I have a 3.5mm lead going to guitar jack (TRS) going from the old laptop headphone port, plugged into either a line input or an instrument input - both sound like it is underwater. I have also tried 3.5mm to XLR input on the soundcard - same problem.

Yes, they would. Your headphone output carries unbalanced stereo. The left channel is on the tip connection, right on the ring, and a shared ground on the sleeve.

However, the line (and XLR) inputs expect balanced mono signals. The input circuitry passes only the difference between the signals received on the tip and ring connections. So if you plug in a stereo headphone output you'll just hear whatever is at the edges of the stereo image; anything in the centre (the same on both channels) is removed -- so no vocals, bass, kick drum etc! Hence your underwater sound.

Any advice welcome,

Buy a 'splitter cable' with a 3.5mm TRS minijack at one end, and TWO quarter-inch TS plugs at the other. Plug the latter into two adjacent line inputs of your interface, and record to a stereo track (with one panned left and the other right).
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Re: Laptop headphone out into Liquid Saffire 56

Postby Sam the Scholar » Sun Oct 18, 2020 9:35 pm

Brilliant, thanks.

2 more quick things..!

I have found a 3.5mm jack splitter cable to 2 x XLR - It feels like balanced and unbalanced signals shouldn't confuse me, but they do. What is / would be the difference between using these vs quarter inch TS plugs? Googling tells me every option is the best option !

I have an old project on this old laptop that I'm thinking of reviving, first thing I wanted to do was listen to it through my monitors that I am used to (instead of headphones). If I wanted to mix on this laptop (through the headphone socket into the focusrite) is there any reason, for fidelity or something else, that this would be unwise? Exporting as stems and setting up in my current set would be no problem, I just like the idea of trying to use a set up (and restrictions!) from a while ago through my current monitors.

Thanks again for the help, greatly appreciated.
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Re: Laptop headphone out into Liquid Saffire 56

Postby blinddrew » Sun Oct 18, 2020 10:30 pm

Sam the Scholar wrote:If I wanted to mix on this laptop (through the headphone socket into the focusrite) is there any reason, for fidelity or something else, that this would be unwise?
The onboard soundcard in most laptops isn't up to much.

Sam the Scholar wrote:Exporting as stems and setting up in my current set would be no problem,
This would be a much better idea. Export them as 24bit wavs and give yourself a fighting chance. ;)
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Re: Laptop headphone out into Liquid Saffire 56

Postby Mike Stranks » Sun Oct 18, 2020 10:31 pm

The XLR inputs on your interface seem to be solely for mic inputs.

You really need to be using the jack line inputs using one of these: https://www.thomann.de/gb/pro_snake_tpy_2060_kpp.htm (not necssarily from Thomann of course!)

WRT your other question - assuming the laptop has any sort of USB connector, my preferred approach would be to copy the files from the laptop onto a USB stick and then import them into your DAW. That way you keep the files in the digital domain and don't send them out through what could be a very poor quality analogue headphone output.
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