Home Theater Forum and Systems banner

1 - 8 of 8 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
In REW I'm wondering if there is a way to add a calibration factor to the Generator basically in the same way you do for the SPL Meter. It would be nice to type in a real SPL value instead of manually converting dBFS to dBSPL. If that's not possible, I'd love it if that feature could be added.

Thanks,
Chris
 

·
Premium Member
Joined
·
6,711 Posts
Tricky to do, since REW has no control over the gain that gets applied after the signal generator (the computer's volume settings, the receiver's volume setting) nor any control of how far away you are from the speaker. Changing any volume setting in the output path or moving the mic or speaker would render any offset applied incorrect, safer not to show an SPL figure than to show one that would probably be wrong.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
What you said makes perfect sense, but my thought is that the SPL meter function already has to deal with the problem gain calibration of external components. What if the Generator would normally use dBFS as it currently does, but if a user presses a calibration button and enters an offset then it would either switch to or also display dB SPL. This seems like a good approach because most users would just leave it set to use dBFS.

Thanks,
Chris
 

·
Super Moderator
Joined
·
9,252 Posts
What you said makes perfect sense, but my thought is that the SPL meter function already has to deal with the problem gain calibration of external components.
Well sure, that’s what a SPL meter is for. But in order to do that REW’s meter first was calibrated against a reference device. IOW, the former is not possible without the latter.

What if the Generator would normally use dBFS as it currently does, but if a user presses a calibration button and enters an offset...
As alluded to above, what would be the source (reference) for that calibration? Changing an electrical reference to an acoustical reference is not readily possible. As John indicated, depending on what’s downstream, any dBFS value can represent literally any dBSPL figure.

Regards,
Wayne
 

·
Registered
Joined
·
4 Posts
Discussion Starter #5
My handheld SPL meter would be the reference, so I would simply measure the level at my location of interest while the generator is running. Then I would hit a calibrate button in REW and type in the SPL value that was displayed on my meter.
 

·
Premium Member
Joined
·
6,711 Posts
I've put it on the list to think about, but I have reservations - not sure I could handle an endless series of 'bug' reports along the lines of "I set the generator to 75 dB but it actually gave...".
 
1 - 8 of 8 Posts
Top