Two sources (desktop PC + Mac) into one speaker setup?

Scam · 18 Oct 2020 at 10:31

Since I've started WFH I've been using a HDMI/peripheral switcher to switch between my personal PC and work Macbook which works rather well to be able to use my existing keyboard/mouse and monitor. I'm using my PC to play music etc. through my Creative speaker setup. It's some old 5.1 system but I only have 2 fronts coming out of the sub due to space. Fine by me.

Now, I realised that I could actually install Spotify on my work Macbook so it seems a bit silly to run my personal PC all day just for music. The Creative sub just has a 3.5mm input, so I'll be finding a 3.5mm cable to plug up my Macbook and should be set. But… I do have an old headphone splitter (1 male to 2 female). So can I plug both machines in at the same time? :confused:

tldr; Can I use my headphone splitter to plug in both my PC and Macbook into the Creative sub, so I don't need to scrabble under my desk should I want to listen to stuff out of my personal PC? :confused:

Marsman · 18 Oct 2020 at 16:55

No reason not to just use the splitter cable. Alternative would be a switcher, but the splitter would be easier as you won't have to change inputs over.

Splitters are often frowned upon by people more concerned with audio quality, when they are used to connect speakers and headphones to a single output. Impedances will be different and will be altered which can affect the sound quality.

No such concern using a splitter the other way round though.

Scam · 18 Oct 2020 at 17:03

Marsman said:
No such concern using a splitter the other way round though.

I didn't think I was in a position to test this because I only had a male-to-female extension (hence the thread), but I managed to find a male-to-male cable from my Chromecast Audio. I gave it a go but with both machines on the volume seemed to jump up and down especially when waking the Macbook.

Perhaps it was my jerry-rigged M>F>M>M>splitter extension though, and actually I'm not likely to have both machines on (that's the whole idea). I've ordered a M>M extension for the Macbook so I can test properly when that arrives. I guess I was just scared I was going to blow up the speakers or something?

Marsman · 19 Oct 2020 at 16:46

My guess is that it's because of differing signal volume.

If you put a signal from machine A down a cable that has a volume of 10 and machine B is sending a signal with the volume of 5 down the same cable, you can't expect the outcome to be of an even volume. That's probably a bit simplified, but you get an idea of why the volume may not be a constant level.

I doubt you will damage the speakers because you are sending what is known as a 'line level' signal, even if from two different sources simultaneously. That same signal is also used for headphones and is not enough to cause damage to headphones, which are a lot more sensitive than a speaker system.

413x · 21 Oct 2020 at 13:58

I have a Bluetooth and USB amp connected to a USB switch

It allows sound from either

Personal pc - USB switch number 1
Work pc - usb switch number 4
Personal laptop usb switch number 2
Phone (Spotify) - Bluetooth on amp

It works well. At work it's 90 percent of the time on Bluetooth. But if I have a work meeting I simply switch the amp to USB and the work laptop sends sound to it

The amp also has a speakers/headphones toggle so same all applies to both speakers and headphones

Scam · 22 Oct 2020 at 12:11

Well this is highly annoying. I'm using a USB-C Digital AV Multiport Adapter to plug my Mac into power/hdmi switcher/kvm and it seems whenever this is plugged in I'm getting almighty signal noise through my speakers. Like, it's louder than the music I'm playing :confused:

As soon as I unplug the adapter the audio is fine… I didn't have this last week when I was testing with my crazy extension!

This never happened before when I was testing with my ghetto cable as above, but with the same cables and/or my new straightforward 3.5mm extension to my speaker setup, it's happening every time so it's unusable. Any ideas? Why would the AV adapter give noise to the 3.5mm out on the other side of the Macbook? :confused: