On 2010-07-04 22:12, Mathieu Bouchard wrote:
The total delay is the sum of the logical delay as written in the audio settings dialogue of Pd
i wouldn't give a groschen for what is written in the audio settings dialogue of Pd. i dare say that the value you see in the dialog jhas a direct relationship [1] to the actual delay you are experiencing.
mfgasdr IOhannes
[1] http://en.wikipedia.org/wiki/Direct_relationship
, plus the digital in-delay and out-delay of the soundcard and/or driver, plus any analogue delay introduced by the soundcard due to filtering, plus the microphone's delay, plus the speaker's delay, plus the room's delay (relative to position and orientation of both speaker and microphone).
In the end, any digital delay can be counted by easy addition, whereas the analogue delays are frequency-dependent and thus have to be counted as filters. So, to measure a room's response, you'd first just subtract the digital delay, but after that, for the analogue effects, you'd need to deconvolve instead (but I suppose that you already know that).
It may be tricky to know the digital delay beforehand... but if you put the microphone and speaker really next (in)to each other, then just look in your recording for the point when the response begins, then it might be quite close to a digital delay, IF your impulsion contains enough high-frequencies. But I don't know how close it is, as I haven't tried it.
The total digital delay is soundcard-dependent, driver-dependent, and OS-dependent, on top of being dependent on a setting in pd.
_ _ __ ___ _____ ________ _____________ _____________________ ... | Mathieu Bouchard, Montréal, Québec. téléphone: +1.514.383.3801
Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list