• Registered: 2009-04-15
  • Posts: 23

Topic: Recording Latency

I have an HDSP card with Digiface, latest firmware and drivers, under Windows XP Pro in a core i7 system. Recently did a percussion overdub session and discovered I was getting an unacceptable amount of recording latency. I normally use the MME driver, which works better with my setup, but found I was getting over 1500 samples of latency on the timeline. Switching to the ASIO driver it was reduced to ony 92, but for some reason my software (SAWStudio) continually freezes when using th ASIO driver model. Plus, I do a lot of post work mixing files of different sample rates, and when locked to external clock I can't audition all the files when using ASIO.

Anyway, my question is: what is an average amount of recording latency? Do most people have adjust for this?

  • From: Houston, TX
  • Registered: 2007-05-11
  • Posts: 1,191

Re: Recording Latency

ASIO is a must.  MME will not do low-latency.

I always run at the lowest buffers even in large projects (32 Samples for HDSPe MADI) - but have a rather powerful 4.8GHz SB-E system to cope.

What's your rig consist of - and are your DPC's consistently nice and low (no spikes)?

cool

MADIface-XT+ARC / 3x HDSP MADI / ADI648
2x SSL Alphalink MADI AX
2x Multiface / 2x Digiface /2x ADI8

3 Reply by seanmccoy (edited by seanmccoy 2012-07-22 01:05:55)

  • Registered: 2009-04-15
  • Posts: 23

Re: Recording Latency

I have a core i7 2.66, so speed shouldn't be an issue. But keep in mind I'm not talking about realtime monitoring latency, but rather recorded audio falling late onto the timeline. I use an external mixer for monitoring, so I don't really need to work with low buffer settings. What I'm wondering is if a certain amount of recording lateness is to be expected, and if so, how much is within tolerance range.

4 Reply by Randyman... (edited by Randyman... 2012-07-22 01:15:36)

  • From: Houston, TX
  • Registered: 2007-05-11
  • Posts: 1,191

Re: Recording Latency

Ah - I always think "monitoring" when talking Latency.  Sorry about that.

I don't believe MME reports it's offset to the Host - so I can see why you might get such a large offset using it.

If I had to guess, the 92 Samples of overdub offset you see using ASIO are due to your AD/DA converters.

The Digiface is strictly a Digital unit (minus the Phones outs) - so it can not correctly report the additional AD/DA conversion latency your converters inherently add (all AD/DA conversion takes time = latency).  The Digiface ASIO Driver only reports the ASIO Buffer offsets to the host - the AD/DA conversion latency will need to be manually specified to get overdubs to line up "sample accurate".

You should be able to specify a "Record Offset" manually somewhere in your software (I know Cubase/Nuendo allow this).  This should allow you to compensate for the AD/DA conversion latency variable and have the DAW automatically slide the overdubs back in place.

cool

MADIface-XT+ARC / 3x HDSP MADI / ADI648
2x SSL Alphalink MADI AX
2x Multiface / 2x Digiface /2x ADI8
  • Registered: 2009-04-15
  • Posts: 23

Re: Recording Latency

I was able to compensate for the measured latency in my software, but I'm still curious as to how much latency from A/D to DAW timeline is considered normal. I realize there will always be a few samples from the A/D (though interestingly I can't find the specs for my Apogee 800's latency anywhere), but do most people have to use compensation for overdub recording? What amount is to be expected using a great card and drivers such as these from RME?

  • From: Houston, TX
  • Registered: 2007-05-11
  • Posts: 1,191

Re: Recording Latency

Since the DAW Software can compensate down to the sample - I'd say no amount of offset is "normal" or "acceptable".  Overdubs should always line up sample-accurate with the backing tracks if everything is setup correctly.

FWIW - If you were using one of RME's interfaces that has Analog I/O - and were using its analog I/O for all connections, you should not have to manually specify any offsets in the DAW Software as the RME ASIO Driver can correctly report the total latency of its ASIO Buffering AND AD/DA conversion latency.  It's only when using external AD/DA converters that this extra AD/DA "offset" generally needs to be manually specified (ASIO Driver can not determine what external AD/DA converters you use via SPDIF/ADAT/AES, etc).

cool

MADIface-XT+ARC / 3x HDSP MADI / ADI648
2x SSL Alphalink MADI AX
2x Multiface / 2x Digiface /2x ADI8
  • Registered: 2009-04-15
  • Posts: 23

Re: Recording Latency

Thanks, understood. As I am using external converters with my Digiface, 92 samples with the ASIO driver seems somewhat within reason. 1500 with the MME driver, obviously, does not. It's good that I can work around it, but not knowing why it's so severe is unsettling.

  • From: Houston, TX
  • Registered: 2007-05-11
  • Posts: 1,191

Re: Recording Latency

92 Samples is indeed within reason for a DA/AD loop - of course some converters are faster and some are slower.  TBH - I thought the Apogee's were faster than that (the AD/DA16x are much lower than 92 Samples, and I assumed the 800's latency was in-line with them).

I don't believe MME reports its offset values to the host software (the DAW) like ASIO does.  Therefore, the DAW cannot compensate (offset) accordingly.  You should be able to set your RME's ASIO driver anywhere from minimum buffer to maximum buffer, and still have everything line-up in your DAW as the RME's ASIO buffer is being correctly reported to your DAW Software.

You could likely specify MME's ~1500 sample offset in your DAW, and be OK.  However - I have no real-world knowledge of MME - Specifically if its buffer remains static in all scenarios (could cause alignment slippage from take to take).  Beware that you are reliant on MME/Window's SRC (sample rate converter) when running in mixed samplerate environments under MME.  You might want to ponder external SRC for disparate samplerates, and stick with the ASIO protocol for "bit perfect" reproduction of the recorded and reproduced sound.  Something to ponder - but certainly not something to re-configure your entire workflow over IMO - especially if you are primarily a composer combining lots of mixed-rate ITB Synths, etc.  As an engineer - you'd never catch me using MME.

Regardless, do whatever you have to do to get your sound IMNSHO.  That's the ticket! :-D

cool

MADIface-XT+ARC / 3x HDSP MADI / ADI648
2x SSL Alphalink MADI AX
2x Multiface / 2x Digiface /2x ADI8