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serr · 01-15-2018, 08:04 AM

OK, so truly doing live performance and requiring low latency.

The only thing that might slow down a high spec machine like that MBP is one of the more CPU intensive synth instrument plugins - and a number of them.

But that would give you high readings on the CPU use in Activity Monitor like you might expect.

Dropouts when you are far from heavy CPU use are usually caused either by a misbehaving buggy plugin or a conflict between different apps both making requests to core audio.

Any other audio apps running? Media player? Browser app?
If so, either quit them during critical audio work or make sure they run at the same sample rate as the live audio system.

It looks like you are reading the numbers off the top of the screen for your system latency. The actual measured latency might be larger FYI. That aside, if you play with the system with no plugins inserted, does it respond as expected? Meaning, does stability follow the block size settings as expected? And then does adding that instrument plugin push it over the edge?

If yes and also with a big CPU hit, then you may have found a ridiculous modern plugin that uses heavy resources. If yes but hardly any CPU hit? Might be a buggy plugin.

Re: 44.1k and 16 bit.
It sounds like you are trying to lower the audio quality to make up for the system limitations. Have you tried 48k (and without reducing the word length to 16 bit)? This is usually the sweet spot for live sound work for latency vs. CPU hit.

There are more samples going through in a shorter period of time. That means the same block size translates to a lower latency. Even though this is more work in a shorter time span, the same latency (as at 44.1k) can now be achieved with a larger block size which gives you more headroom in other areas. This crosses the line if you go to HD (96k) but 48k is usually the sweet spot. (Again, keeping the audio at 24 bit.)

01-15-2018, 08:04 AM	#11
serr Human being with feelings Join Date: Sep 2010 Posts: 12,632	OK, so truly doing live performance and requiring low latency. The only thing that might slow down a high spec machine like that MBP is one of the more CPU intensive synth instrument plugins - and a number of them. But that would give you high readings on the CPU use in Activity Monitor like you might expect. Dropouts when you are far from heavy CPU use are usually caused either by a misbehaving buggy plugin or a conflict between different apps both making requests to core audio. Any other audio apps running? Media player? Browser app? If so, either quit them during critical audio work or make sure they run at the same sample rate as the live audio system. It looks like you are reading the numbers off the top of the screen for your system latency. The actual measured latency might be larger FYI. That aside, if you play with the system with no plugins inserted, does it respond as expected? Meaning, does stability follow the block size settings as expected? And then does adding that instrument plugin push it over the edge? If yes and also with a big CPU hit, then you may have found a ridiculous modern plugin that uses heavy resources. If yes but hardly any CPU hit? Might be a buggy plugin. Re: 44.1k and 16 bit. It sounds like you are trying to lower the audio quality to make up for the system limitations. Have you tried 48k (and without reducing the word length to 16 bit)? This is usually the sweet spot for live sound work for latency vs. CPU hit. There are more samples going through in a shorter period of time. That means the same block size translates to a lower latency. Even though this is more work in a shorter time span, the same latency (as at 44.1k) can now be achieved with a larger block size which gives you more headroom in other areas. This crosses the line if you go to HD (96k) but 48k is usually the sweet spot. (Again, keeping the audio at 24 bit.)