Latency questions and tests
I have been investigating this issue for a while. I am currently using a 8 channel soundcard from M-Audio which in Windows 8 (24 bit and 96KHz) gives an output latency on 1.3 ms using the ASIO Test from Centrance called LTU. It measures the round-trip latency from the analogue input via the PC to the analogue output. (So it is counting both the input latency and the output latency referred to above)
However – When dealing with e-drums…the analogue input goes via PADs, module and USB midi. The forums around the world claims that a TD-30 has a latency on about 4 ms and the 2BOX module about 3ms before it arrives to the PC or a MAC via the USB port. Then you have the VST plugin softwares which generates the sound like Superior Drummer, Addictive DRUMs also adds latency because the computer needs to process the information before the sound is sent out to the sound card. All together (A drumhit on your pads until you hear the sound from the earphones or speakers) should not hopefully reach above 10ms in latency…above 10ms you are starting to hear and feel the latency
As said – It could be a bit tricky to really measure the whole chain. I came up with my own way to measure latency using a 4 channel Zoom H2N where I use the internal stereo MIC(listening to the output speakers) in combination with a external Mic (tracking the e-pad – when I hit the pad). I will then get 4 separate channels in a row and using a sound processing software like Audacity and open all the soundtracks…I am able to measure between the sound waves (E-PAD compared to speakers) and get the exact latency.
So – Which latency figures was I able to get on my system? I am using a ARM based MegaDRUM trigger device (Which in it self reports about 1.0-1.2 ms in latency counted from the pad to USB midi port) and I use it all on a 5 year old notebook using Windows 8.
For the total chain – my system is actually reporting a total latency on 5 ms.
But, I am not satisfied yet…the VST process time can be lowered, so I have now changed to a faster PC system…and are running Windows 8.1(faster than Windows 8)…and I will soon post my findings on my site. www.zourman.com