Impulse IR export

[audioexplorations]

Hello, I would like to know what the units are of the IR export tool when not normalized.

I take it this is not a Pa pressure level, and hence SPL cannot be reconstructed from the exported data?

I am asking as I am comparing REW with a MiniDSP UMIK-2 to CLIO Pocket and I am seeing a ~9dB offset in SPL with all other variables kept constant.

Thank you

* Impulse Response data saved by REW V5.31.3
* IR is not normalised
* IR window has not been applied
* IR is not the min phase version
* Source: UMIK-2, UMIK-2, L, volume: 1.000
* Dated: Sep 24, 2026 9:42:31 PM
* Measurement: L 2026-09-24-tests-totaldacd2 Sep 24
* Excitation: 128k Log Swept Sine, 1 sweep at -3.2 dBFS with no timing reference
* Response measured over: 20.1 to 20,000.2 Hz
0.0036373320035636425 // Peak value before normalisation
48000 // Peak index
131072 // Response length
2.0833333333333333E-5 // Sample interval (seconds)
-0.9999999968540269 // Start time (seconds)
* Data start
5.67492E-8
9.45833E-8
-9.896201E-8
1.1779071E-7
1.8438108E-8
-9.574251E-8
-3.0707218E-7

 

[John Mulcahy]

dBFS. You can see the offset REW is using to generate SPL from the Info panel for the measurement.

Edit: more precisely the values are relative to the full scale of the input data.

 

[audioexplorations]

Thank you. I looked for some time but am not sure I could not find and offset in the measurement info panel. Is it the 110.9db "data offset" value?

when I compare a CLIO IR export to a REW IR export (both converted to FR using the virtuixcad IR to FR tool, I am seeing a delta of around 9dB (the phase matches decently). CLIO in red, REW in blue.

 

[John Mulcahy]

Is it the 110.9db "data offset" value?

Yes.

when I compare a CLIO IR export to a REW IR export (both converted to FR using the virtuixcad IR to FR tool, I am seeing a delta of around 9dB

I don't know how VituixCAD decides to convert IR import levels to SPL, or how Clio scales its exports, sorry, but I would imagine it is easy to offset one or the other in VituixCAD.

 

[audioexplorations]

Your answer helped me determine there is a scale field in vituixcad IR-FR tool which was set to a default 100dB, setting it to 110.9dB resulted in a perfect match. Thank you!