HW Buffer Size at Different Sample Rates

[abc1mce2]

I usually don't record above 48K but today I was doing a track count test recording a 1k signal to 100 tracks with a DSP reverb send and 2 DSP plugins per track at 96K. I had the HW buffer size at 64 (the lowest I can go) for my standard 48K template session before loading a 96K template sessions and adding my tracks and auxes. I just happen to check my playback engine and saw the lowest HW buffer size I could use is 128 at 96K. I decided to change my sample rate to 192K and saw the lowest HW buffer setting was 256. Is this normal when doubling the sample rate and for you Mac guys at 48K, can you get your HW down to 32? Also with this number doubling at higher sample rate is this changing the latency as well or is the latency staying the same and the number changed due to the higher sample rate?

[BScout]

Latency and sample rate are related. Doubling the sample rate means the same amount of buffers go by in 1/2 the time. So doubling the buffers restores the same amount of time.

Remember
buffers is equivalent to a measure of samples.
samples / sample rate = latency

You haven't mentioned what your audio card is but all audio interfaces will have a minimum time needed to process incoming audio and that will set your minimum buffer. Since you started with the minimum at a base sample rate, it will have to go up in proportion as you double or quad the base sample rate.

[abc1mce2]

Originally Posted by BScout

Latency and sample rate are related. Doubling the sample rate means the same amount of buffers go by in 1/2 the time. So doubling the buffers restores the same amount of time.

Remember
buffers is equivalent to a measure of samples.
samples / sample rate = latency

You haven't mentioned what your audio card is but all audio interfaces will have a minimum time needed to process incoming audio and that will set your minimum buffer. Since you started with the minimum at a base sample rate, it will have to go up in proportion as you double or quad the base sample rate.

HDX card and HD I/O.

[Emi]

Well, in my case the lowest latency I obtain with my system is at 96khz. Actually at 192 I have more latency than at 96 with the same buffer size. Maybe it depends on the interface you use....don't know. But normally, at let's say 64 sample buffer size / 48 khz corresponds to 128 / 96 and 256 / 192.

Also at higher frequency rates the quantisation noise gets higher because the anti-aliasing filter is set to a higher frequency. But that's another story...