Using a 13" MacBook Air as an audio delay.

December 26, 2013 7:56 AM

This is for live sound at a party. I need to add a delay to a set of speakers to synchronize them with the main stacks. I don't have a digital console or an effects box capable of this. Could I use something like Audiomulch to do it? How would I set up my 13" MacBook Air so it won't shut don't or cut the audio for several hours?

Not married to Audiomulch at all. I'll use whatever is practical/affordable. I plan to input/output the sound through the USB interface of an Allen&Heath Zed10 (not FX, unfortunately).

posted by Monday, stony Monday to Technology (8 answers total)

You want this.
posted by oceanjesse at 8:19 AM on December 26, 2013

You could use Reaper with a stereo track set to 'monitor input', and insert the ReaDelay plugin 100% wet, 0% dry, and adjusting the delay time to taste.
posted by toastchee at 8:29 AM on December 26, 2013

I think Audio Hijack (would need to be registered version) will do it.

All the sleep settings can be changed in System Preferences. No idea if there are any timeouts on audio input/output, but I doubt it.

Going through a computer will never be as reliable as something more solid state, so hopefully it wouldn't be too disastrous if the audio cuts out for a second or two over the course of the few hours
posted by supercres at 8:58 AM on December 26, 2013

What does your setup look like? Is this an audio rig that you're hoping to put a macbook air in the middle of to add a delay? Is the audio coming from the MBA and going to two different sets of speakers? Are there sound cards involved?
posted by Jairus at 10:39 AM on December 26, 2013

The idea was to use the delay for a second set of speakers. Main mix to USB, USB to Mac, Mac to second set of speakers through a set of isolation transformers. The console has one of these "driverless" USB in/out.
posted by Monday, stony Monday at 10:29 AM on December 27, 2013

Okay -- and why do you need to delay the second set of speakers? Or more appropriately, why is there a delay on one set of speakers in the first place? Just so I can think of if there's a more elegant solution.
posted by Jairus at 10:04 PM on December 27, 2013

Because they are closer to the audience, and I want to avoid a distracting echo. It's never going to be perfect of course, because the distance to each speaker varies depending on the exact position of the listener, but on average there's going to be a 30 feet difference, so a little less than 30 milliseconds.
posted by Monday, stony Monday at 9:01 AM on December 28, 2013

OK, I think I was misunderstanding earlier. So this is a situation where you're trying to delay fills to match the main stack.

Really what you want to do is go to a local music store and rent a digital delay for the night for $20. That will be a thousand times simpler and more reliable than trying to get it synced with the macbook.

If you need to use the Macbook, I'd install Ableton Live, and then route the input through to the master, using the 'channel delay' option at the bottom of the track and increasing it until things sound right. I would imagine you're going to get at least 5ms latency in and 5ms latency out through the MBA, which means you'll probably want to add about 20ms of latency, but if you just play a click track you should be able to get it synced pretty fast.

Seriously though just rent a digital delay for $20.
posted by Jairus at 12:12 PM on December 28, 2013