The following file is a sweep from 22050 Hz. down to 20 Hz at a level 20 db below maximum CD leve. Sample rate is 44.1 kHz with 16 bit words. Note that the following file is a very large multi-megabyte file and will take time to download.
Here is a wave file that contains tones at a level 20 db below maximum CD level for each of the following frequencies:
1000.00 Hz 0.5 Sec
20.00 Hz 0.5 Sec
31.25 Hz 1.5 Sec
46.88 Hz 0.5 Sec
62.50 Hz 1.5 Sec
93.75 Hz 0.5 Sec
125.00 Hz 1.5 Sec
187.50 Hz 0.5 Sec
250.00 Hz 1.5 Sec
375.00 Hz 0.5 Sec
500.00 Hz 1.5 Sec
750.00 Hz 0.5 Sec
1000.00 Hz 1.5 Sec
1500.00 Hz 0.5 Sec
2000.00 Hz 1.5 Sec
3000.00 Hz 0.5 Sec
4000.00 Hz 1.5 Sec
6000.00 Hz 0.5 Sec
8000.00 Hz 1.5 Sec
12000.00 Hz 0.5 Sec
16000.00 Hz 1.5 Sec
20000.00 Hz 0.5 Sec
1000.00 Hz 0.5 Sec
Bach quantified our measurment of pitch when he developed the equal tempered scale with 12 geometric steps in an octave. Thus each step is a frequency ratio of the twelveth root of two or about 1.059463094.
Scale @ -20 dbfs Scale steps from middle 'C' to the 'C' an octabe above in half tone steps of 1 second each.
The following impulse files were created for testing for delay. 'Pulse' consists of a series of maximum level, single sample impulses, both plus and minus. 'Wide Pulse' consists of a series of positive level of the shape -2, 12, -39. 157, 157, -39, 12, -2. This impulse does not generate energy at the half sample rate. These impulses have been scaled up to a larger size.
To set up the test, play the wav file, pass it though the D/A and then the A/D and record the file. From the captured file, any preechoes should be visible. It might also be possible to see postechoes.
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