Line out to RCA to...AUDIOPHILE HEAVEN
February 1, 2019 7:15 AM   Subscribe

I play music from my computer through a mini-plug line-out that splits into RCA plugs and goes into my amplifier and speakers. I have a decent higher range stereo amplifier and I have some Infinity bookshelf speakers. Two questions: for the purposes of sound quality, does it matter whether I turn up the sound on my computer or on my amp? I have a USB audio out device, for the purposes of sound quality should I use USB out instead of mini-stereo out to send sound from my iMac to my stereo amp?
posted by OmieWise to Technology (9 answers total) 1 user marked this as a favorite
 
Does your stereo amplifier have a digital audio input? If so, it is likely that the digital to analog converter in a modern high-end stereo is better than the one in either your PC or an inexpensive USB audio device. If so, try using a USB or PCI device with a digital audio output to connect your PC to your stereo. If your iMac is a 2015 or older model, it has a combination 3.5mm headphone / SPDIF jack that can output digital audio.
posted by RichardP at 7:32 AM on February 1, 2019 [2 favorites]


Just to check: is TOSLINK an option for your specific iMac and stereo amp?
posted by zamboni at 7:36 AM on February 1, 2019


To take the second question first: try it. The main artifacts you're likely to notice quickly from a low quality digital to analog converter are background hiss and hum. If you can get less of those from one of your available interfaces than the other, use the quieter one. If you're using a half-decent USB audio device I would expect it to have nicer post-DAC analog electronics than your Mac does, but only a head-to-head test will tell you for sure.

On preview: as RichardP says, if your amp has a digital audio input and you can get a digital audio output from the Mac (perhaps via HDMI?) then you'll probably get better results from using that.

To the first question: to maximize the difference between the reproduced sound you want to be listening to and the assorted sources of noise picked up by the low level analog inputs on your amplifier, you want the amplifier to be doing the least amount of amplification it possibly can for the output level you want.

The volume control on your computer is implemented in software. Every 3dB you back it off from full output effectively costs you one bit of conversion capacity in whatever DAC you're using, be that the one built into your computer or the one in your USB interface or one in the amp itself.

For both these reasons, it's better to have the computer volume control set at maximum and use the volume control on the amp to set your listening level.
posted by flabdablet at 7:37 AM on February 1, 2019 [4 favorites]


Honestly, I think it's probably a matter of preference and you can play around with it. This is only in my experience but boosting the computer volume makes the audio quality better but only to the point right before you start to get some distortion on the speakers. If it gets to that spot and it still doesn't feel loud enough, I turn up the audio device.
posted by dawkins_7 at 7:39 AM on February 1, 2019


See my earlier question, as well.
posted by Admiral Haddock at 7:53 AM on February 1, 2019


Further to the Apple advice behind zamboni's TOSLINK link: high sample rate audio for playback is a complete wank that will not make your music sound any better and might make it worse. Monty explains why.

That said, there is nothing wrong and a great deal right with TOSLINK as a method for connecting computers to amplifiers. Use it if you have it.
posted by flabdablet at 8:05 AM on February 1, 2019 [3 favorites]


Two questions: for the purposes of sound quality, does it matter whether I turn up the sound on my computer or on my amp?

You don't want to overdrive the amp's input; so there is probably a point where the computer sound is up too loud. This kind of concern is called gain staging.
posted by thelonius at 9:34 AM on February 1, 2019 [2 favorites]


Thanks all! The only reason I have a decent amp is because it was a cheap garage sale find and is too old for any digital input. Although it’s sadly too young (or I guess too old again) for a phono in.
posted by OmieWise at 11:57 AM on February 1, 2019 [1 favorite]


You don't want to overdrive the amp's input

That's quite true, but in fact you're unlikely to do that with the line out signal from a USB DAC. Possibly an issue for the headphone port though.

You can find out if you're overdriving the amp's input by playing something you're familiar with, then winding up the computer's volume control while winding down the amp's in order to keep the playback level the same. If you reach a point where you start to hear distortion, that's most likely overdrive. Wind the computer volume control down until it goes away, then use the amp's volume control to set the listening level from there.
posted by flabdablet at 1:39 AM on February 2, 2019 [1 favorite]


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