Playsound and SoundinStatus commands

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Sun, 09/07/2008 - 10:10 am

Hi,

i am using IgorPro V6.04 on a MacBook Pro.

i can get sounds to play correctly at 44.1 and 48 KHz but not at 96 KHz.

this all makes sense given that the w_soundinrates wave created by SoundinStatus command reports back 44.1 and 48. however the MIDI settings of my macbook suggest that the soundcard can output 96 KHz.

my question is: why doesn't the w_soundinrates wave values reflect all the sampling frequencies of the soundcard?

thanks.
Okapi wrote:

my question is: why doesn't the w_soundinrates wave values reflect all the sampling frequencies of the soundcard?


Probably because we are not using the latest API for sound. I'll investigate what it would take to modernize this aspect of Igor but likely it is a huge effort for very little gain.

September 8, 2008 at 07:42 am - Permalink



Thanks for looking into this. I think there might be some useful gain in updating this aspect of igor because sound cards are getting quite powerful and inexpensive (you can get a multichannel 192 Khz, 24 bit card for a couple hundred bucks) and now represent a reasonable alternative to other more expensive DACs/ADCs.

thanks again.

September 8, 2008 at 12:23 pm - Permalink

i have some related follow-up questions.

what are the differences between using the soundinrecord command and a FIFO (with the soundinstartchart command)?. i notice that in at least one of the example files (soundsystem eval) there seems to be a preference for using a FIFO over the soundinrecord command.

does it have something to do with how the buffering and writing to disk is handled?

if i use the soundinrecord command when can i expect the recording to be interrupted for a disk write?

thanks for the help

September 11, 2008 at 03:01 pm - Permalink

Okapi wrote:

what are the differences between using the soundinrecord command and a FIFO (with the soundinstartchart command)?. i notice that in at least one of the example files (soundsystem eval) there seems to be a preference for using a FIFO over the soundinrecord command.

does it have something to do with how the buffering and writing to disk is handled?

if i use the soundinrecord command when can i expect the recording to be interrupted for a disk write?


SoundInRecord would be used for a fairly short fixed time recording as it simply fills up a wave you provide. The disk is not involved.

The FIFO method is used for continuous recording of indeterminate length. It can (but does not have to) be connected to a disk file.

Neither are interrupted due to disk activity.

September 13, 2008 at 07:33 am - Permalink

Okapi wrote:
W_SoundInRates[0]= {3,44100,48000,96000}


thank-you!


You can thank some other users that were hounding me to modernize the sound on Mac.

6.11 now uses Core audio and can support floating point data, high sampling rates and multiple channels.

September 2, 2009 at 03:01 pm - Permalink