NI-USB 9229: amplifying sound values for wav writing?

[acgrama]

Hello all,

I am using a NI-USB 9229 to acquire sound (I know it's not the best device for this, but unfortunately I have to work with it).

So I'm getting sound from an iPod through the NI, and the values are very small (+/- 0.4V, on average) compared to the range of the 9229 (+/- 60V). I was thinking of amplifying the values "artificially".
However, there's a catch: I'll have to save the samples at some point in the form of a wav file. Working with 8 bits, mono sound, the sample values in the wav need to be (so I understand) in the [0..255] interval. Does it make sense to "normalise" the negative and positive values received through the NI w.r.t. the [0..255] range?

Thank you in advance for any advice regarding this!
--Cristina.

[Duffy2007]

Hello Cristina,

a normalisation can be made as last process to rearange the signal to 0 db.

Yes, the 8 bit wave signal should be unsigned so it is in an range from 0 to 255.

What exactly mean w.r.t?

[acgrama]

Thanks a lot for your feedback!

PS. w.r.t. = with regard to 🙂