Arithmetic inversion suggestion - Home Theater Forum and Systems - HomeTheaterShack.com

Old 08-31-12, 06:23 AM Thread Starter
Shackster

CF

Join Date: Mar 2010
Location: FIN
Posts: 30
Arithmetic inversion suggestion

Would it be possible to include arithmetic inversion (B = 1 / A) in the future REW versions?
CFmartin is offline

Old 08-31-12, 09:41 AM
REW Author

John

Join Date: Apr 2006
Location: UK
Posts: 6,296
Re: Arithmetic inversion suggestion

It would, but handling level needs some care - what level should '1' represent? Would probably need to choose a desired target level, e.g. 75dB/A, so that the result of A*B afterwards would be a flat line at the desired level.
JohnM is offline
Old 08-31-12, 12:12 PM
Senior Shackster

Join Date: Dec 2011
Posts: 239
Re: Arithmetic inversion suggestion

A single full scale sample serves as basis, this waveform may be generated in other software, and imported to REW. Scaling is problematic, but REW has no trouble returning the amplitude portion, however REW doesn't return the impulse response:

This isn't always the case. When two similarly produced impulse responses have A/B performed, a resultant waveform is generated.

I don't know how John is doing the math.

A * B in frequency domain is convolution in time domain, and once again scaling can be problematic in REW implementation, but works.

Andrew
Barleywater is offline
Old 08-31-12, 02:46 PM Thread Starter
Shackster

CF

Join Date: Mar 2010
Location: FIN
Posts: 30
Re: Arithmetic inversion suggestion

Hmm... good point John! Holm Impulse uses 0dBfs as a "mirror line". Some sort of adjustment would be useful in certain cases.
CFmartin is offline

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