Custom Averaging Range Option?

[HD MOVIE SOURCE]

Hey,

Is it possible to add a custom range to SPL Alignment? For example. A typical pink noise test for a subwoofer channel is from 30hz to 80hz. The center frequency of the test tone is 55hz, so using 1 octave above and below is too far away from 30 and 80hz. But, setting SPL Alignment to 55hz is not possible right now. I could only choose 50 or 63. It would be inaccurate because the test tone falls off after these points with 1 octave so the alignment level wouldn't be correct.
Aligning to 40hz would get you the closest, but, it still wouldn't be an exact SPL alignment.

If you run speaker pink noise that's from 500hz to 2000K, with a center frequency of 1K. This can be done in REW with SPL Alignment.

Is it possible to add a checkmark on SPL Alignment named, "custom range"?
This would allow users to manually choose the SPL Alignment's center frequency and the start and end points.

I would set my center frequency to 55 with a range of 30hz to 80hz.

Could the SPL Alignment tool be updated to include this type of functionality or is it locked to octaves?

 

[John Mulcahy]

The span is a total figure, so 1 octave is half an octave either side of the chosen centre.

 

[HD MOVIE SOURCE]

The span is a total figure, so 1 octave is half an octave either side of the chosen centre.

So, would a 50hz center frequency be 25hz and 75hz? I think it would be nice to have absolute control over the ranges personally. I'm not sure how difficult it would be to implement, but it would certainly be a nice addition. Thanks, John.

 

[John Mulcahy]

No, 50 Hz centre at 1 octave would be 35 Hz to 71 Hz (approx). For half an octave the factor is sqrt(2).

 

[HD MOVIE SOURCE]

No, 50 Hz centre at 1 octave would be 35 Hz to 71 Hz (approx). For half an octave the factor is sqrt(2).

Okay, so if the center frequency is 1K, and 1 octave is used, what are the frequencies? I've always assumed it was 500hz to 2000Hz. Would that be 2 octaves?

 

[John Mulcahy]

Yes, that would be two octaves. 2000/500 = 4 = 2^2. If span is s the lower and upper frequencies are fc/(2^(s/2)) and fc*(2^(s/2)). For one octave span the factors are 2^(1/2) = sqrt(2) = 1.4142.

 

[HD MOVIE SOURCE]

Yes, that would be two octaves. 2000/500 = 4 = 2^2. If span is s the lower and upper frequencies are fc/(2^(s/2)) and fc*(2^(s/2)). For one octave span the factors are 2^(1/2) = sqrt(2) = 1.4142.

Good to know, thank you John.

 

[christiandickey]

Ok, so what would it look like with an alignment span of lets say 5kHz with the alignment span over 5 octaves?