4 channel synchronized output from MacBook Pro


2019-12-02 1:33 am
I'm performing the experiment to triangulate 3D location from 4 speakers Using time difference of arrival.

To do this I have generated a 4-track WAV audio-file containing staggered pulses.

I then purchased two identical USB sound card and created an aggregate device on my MacBookPro using AudioMidiSetup.app comprising the audio out of each of these soundcards.

I connect each soundcard's (stereo) output to two (MONO) JBL-Go speakers.

I am then able to play my WAV And the sound comes out through the 4 JBL-Go speakers.

However I am detecting a latency of around 500 samples between the soundcards.

I'm disappointed by Apple's engineering here. 500 samples corresponds to an error of 3.5 m.

I am planning instead to purchase a 4-output soundcard, e.g. https://www.amazon.com/ESI-MAYA44-USB-Audio-Interface/dp/B002HLVQIA

I chose JBL-Go because they report a good frequency response at up to 20 kHz and I am using 17.5 to 19.5. Also they are portable (able to operate off battery) and support a mono 3.5mm input. However they do seem to be underpowered for outdoor testing.

Could anyone recommend a more appropriate soundcard, or more appropriate speakers, or even a better software set up for playing the sound?

Interesting project.

A basic "5.1" soundcard should do what you need, though. I've used some really cheap ones and they work fine - outputs go where they're expected, etc etc.

You might want to play around with some DAW software. Look it up. It's made for studio recording stuff, which means there's a large suite of processing available.

The JBL Go is a speaker I wouldn't bother with unless it was for listening to an audio book or similar. Vocals are okay, but it doesn't bother with anything <200Hz-ish.
Of course, it's a tiny box and Physics won't let you get much/any bass out of it.

How much output you're looking for will dictate the speakers you end up with.

If you can provide a bit more info about the project, you might get some recommendations.



2019-12-02 1:33 am
For the record, the "ESI MAYA44 USB+ 4 In / 4 Out Audio Interface" seems to provide sample-synchronized audio output.

I'm now hunting for an amp that can drive 4 channels, while (1) preserving sample-synchronization, and (2) giving good frequency response at 17-20kHz.

I'm planning to just connect a tweeter to each of the 4 amp-outputs as I never output < 10kHz.

Can anyone recommend a suitable amp?


Paid Member
2004-10-07 6:05 am
I've used 4 channel USB cards for years and they work just fine. I actually use one to listen to Quadraphonic. It's the no fuss way to go.

At work we have a couple of 10 channel cards, but they are Firewire so a bit outdated. Still work great on the Mac Mini