csw900 wrote:I would be interested to know how you have measured latency --
are your figures merely estimates or guesses?
Hello csw900,
I haven't specifically measured the internal latency with DirectSound, but if using the same buffer size (e.g. 2048, which itself adds a minimum of about 48 ms at 44.1 kHz) with a semi-professional/professional audio interface with good-quality ASIO drivers, and then comparing that to the same buffer size with a DirectSound driver (whether manufacturer-supplied, or Windows' default) for the same device, then the difference in perceived latency when playing is very obvious -- notes sound noticeably more sluggishly with the DirectSound driver even with the same buffer size. My impression is that the overall latency is around twice as much with DirectSound -- a total latency feels like it's in the region of 70-100ms with DirectSound for a buffer size/latency of 2048. The same has been true for every audio interface I've ever tried.
(You wouldn't actually be able to try that test yourself with a buffer size of 2048 in Hauptwerk, since the largest buffer size it allows for ASIO is 1024, to avoid people accidentally setting the buffer size unnecessarily large, but I can try it here at 2048.)
The same may or may not be the case with ASIO4All for any given device, but it's unlikely that a third-party driver (ASIO4All) would be able to achieve lower latencies than a good-quality professional manufacturer-supplied driver, since latency with ASIO will be a critical benchmark on which audio interfaces are judged and purchased by musicians.
Also ASIO drivers (at least good ones) should report total internal latencies accurately, which is necessary for proper audio-to-MIDI synchronisation in MIDI sequencers. Hauptwerk's log shows their reported figures. DirectSound drivers don't provide such a means to know/query internal latencies (and thus can't give accurate MIDI-to-audio synchronisation in sequencers). ASIO drivers also support multi-channel operation properly, with synchronisation between channels.
But if the latency and performance of DirectSound drivers don't bother you for your purposes then of course that's fine.
Best regards, Martin.
Hauptwerk software designer/developer, Milan Digital Audio.