OT: Buffer Settings

[mr_es335]

Good day,

Just curious...but may I ask what Out Preload Buffers and what In Preload Buffers you folks are using?

The default is Out Preload Buffers of 4 and the In Preload Buffers of 6

Also, what buffer sizes are you using as well?

Thanks.

PS: I do understand that these settings are hardware-specific...but I AM curious nonetheless.

[cgrafx]

here is a latency chart I posted a while back (times are in milliseconds). I run 1x64 but will be looking to see if I can get 1x32 stable on a new build I'm working on.

[UpTilDawn]

Working with SAW buffers and not using the SAC link, my practices have been guided by Bob's suggestions going way back and I adjust things based on my hardware's ability to handle the load.

Generally speaking, for recording directly into SAW on the first pass, I will try to get buffer sizes as low as the machine can handle it, with as low latency as possible and without glitches.

For overdubs, which I haven't routinely done for a long time, I'm pretty much forced to use the SAC link to get low enough latency - aside from the added conveniences that link brings to the game.

For mixing and editing, with a fair number of vst processes going on, I generally (and this is without the SAC link) bump buffers up to 1024 or higher and at least 4 buffers - I also generally set input and output buffers the same these days and regardless of whether using the SAC link or not.

I'm still using 32 bit SAW and SAC on a Win7/64 bit pc, with RME Hammerfall interfaces - this pc has issues, so my numbers have not been great as of late. But I think my modus operandus remains the same regardless the power and efficiency of the pc and interface.


and yes - modus operandus is intentional, so don't correct me on it...

[Cary B. Cornett]

The buffer settings are not JUST hardware specific. Yes, some hardware can work at lower latency than other hardware (mostly a matter of how well the drivers are written). However, some plugins, particularly some VSTi's in my experience, will glitch unpredictably if SS buffer settings are set too low. This may (I'm not sure) also be affected by how many tracks you are running, in combination with the plugin loads on the tracks. Be aware also that auto latency compensation required for some plugins imposes more latency on any live inputs you are monitoring. IIRC, if you are running the SAW/SAC link, SAC operates at its normal low latency while SAW buffer sized automatically "relax" to a size of 1024. This works fine UNLESS you are trying to play a VSTi live from a keyboard in SAW, where you will hear a definite delay between hitting the key and hearing the note.

[mr_es335]

Cary,

...while SAW buffer sized automatically "relax" to a size of 1024

... Interesting! May I ask where you obtained this information?

[cgrafx]

Cary,
... Interesting! May I ask where you obtained this information?

There is a thread somewhere here where Bob provided this information.

When SAW/SAC is used together, SAC does all the heavy low latency lifting and SAW studio is automatically adjusted configured to the higher buffer settings.

The issue of latency in live VSTI plugins can be partially mitigated by setting up the VSTi in SAC rather than SAW Studio.

[jmh]

A little side topic, I just use saw (and not in live mode) and have not played with the buffer settings (in fact nowadays I may have the default) and generally have a modest track count. Some of the plugins I've been using lately are more demanding, so some projects are pushing up the cpu toward the limit.

Years ago I played with those settings. I just remember minimal values may make it prone to throw a message. How much can the buffer settings impact the overall cpu load?

[cgrafx]

Years ago I played with those settings. I just remember minimal values may make it prone to throw a message. How much can the buffer settings impact the overall cpu load?

Buffer size will have a huge impact on CPU load. Its an inverse relationship. The smaller the buffer size the higher the CPU load, so a buffer size of 64 will have a significantly higher CPU load than 1024.

The input buffer is filled at a constant rate (dependent on clock rate - 44kHz, 48kHz, 88kHz, etc). The bigger the buffer the more time there is to process the buffer contents before the next buffer is filled. Conversely, the smaller the buffer, the faster it gets filled. If the CPU doesn't have enough time to process the data between buffer dumps it becomes a slipped buffer.

The less time the CPU has to process the buffer data the higher the CPU load. Faster CPUs process data faster allowing for smaller buffer sizes or higher channel counts or more effects. Increasing the buffer size increases the time available to process the data and reduces the CPU Load, but also increases the latency through the system.

[Dave Labrecque]

Interesting that you save on latency when the setting is half the buffer size and double the buffers. I woulda thunk the latency wouldn't change.

[Dave Labrecque]

...and yes - modus operandus is intentional, so don't correct me on it...

Then the burden is on you, sir, to explain the difference in meaning between that and the phrase we've all heard.