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Latency 
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Joined: 17 Apr 2003, 23:00
Posts: 2
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Forgive the silly question, but what exactly is latency (passage of time between what events?) for a sound card, and what effect does high latency have on the the sound quality? Also, do you have frequency response curve data on the UASC-1 out to 20khz? I need to do some experimentation with ultrasound.... Thanks.


18 Apr 2003, 08:44
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Joined: 15 Oct 2001, 23:00
Posts: 687
Location: France
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Latency is the time between you decide to produce a sound and the moment of you can ear it.
In some audio applications, it is mandatory to have it as low as possible ... for instance, you have a midi keyboard producing note on and off, connected to your computer (which produce the sounds), when you press a note, it is important that you ear this note immediately, without having to wait several miliseconds !
For your information, a "normal" person is not able to ear latencies below lets say 5 to 8 ms.

Regarding the frequency response of the UASC-1, it is very flat (+- 0.5 dB) over the whole audio bandwidth (0 to 20kHz), higher frequencies are fully attenuated by a cascade of low pass filters ... if interrested to see some plots, send us you email and we will send you the full audio characterzation of the UASC-1.


18 Apr 2003, 11:07
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Joined: 15 Oct 2001, 23:00
Posts: 687
Location: France
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hmmm I forgot ... there is no relation between latency and audio quality.


18 Apr 2003, 12:06
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Joined: 17 Apr 2003, 23:00
Posts: 2
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Thank you, Jerome, very informative. I would appreciate your sending me the frequency response plots, to: bhouston@universal-data.com. Is it possible to bypass the low pass filter cascade (solder jumpers, etc.) to enable conversion past 20kHz? If so, up to what frequency might the device accurately convert? If not, do you know of an "ultra-sound" card that might interface an ultrasonic sensor to USB to get up to 50Khz or so? Thanks, Bruce.


20 Apr 2003, 21:24
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Joined: 15 Oct 2001, 23:00
Posts: 687
Location: France
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We will send you the plots ... no problem ..
You will not find any audio card that allows to acquire data up to 50 khz, even sound cards working at 192 khz are limited to the audio bandwith (< 20khz) since the human ear is not able to recognize frequencies higher than let's say 15 khz for a "normal" person ...


21 Apr 2003, 17:33
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Hello! Can I receive a copy of that plots about band curve responce?

Thank you, I'm at "dino@pro-netics.com".


12 Dec 2003, 15:21
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