REW speaker measurements - how important is the amp?

[rokr]

I want to take measurements of speakers I've built (the speaker itself, not the room. using a daytonaudio usb umm-6 mic).
I can setup a rig in the backyard, but taking my Denon receiver outside would be too complicated, which led me to the question of the importance of the amp while measuring a speaker.
I have an old NAD receiver and a tiny wuzhi zk-1002t amp(both without hdmi or usb), but i really don't know if they are good enough for the job, actually, i dont know if the denon is...
So, should the amp used, go through some tests or calibrations? and is there a guide for measuring speakers using a usb mic and an amp?
Thanks

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[pma]

Old NAD, if in a good condition, will be much better than new low-cost class D with no PFFB, like so many TPA32XX (and similar) based amplifiers are. No PFFB class D amplifiers have frequency response dependent on speaker complex impedance and the deviation above about 8 kHz may be as big as 2 dB.

 

[AaronDC]

Probably none. This is easy to test, however. Test, swap amps, test again. Compare results. Done. Post your findings.

 

[rokr]

Old NAD, if in a good condition, will be much better than new low-cost class D with no PFFB, like so many TPA32XX (and similar) based amplifiers are. No PFFB class D amplifiers have frequency response dependent on speaker complex impedance and the deviation above about 8 kHz may be as big as 2 dB.

I understand that an ab amp is more suitable for this task, but it still doesn't mean that it's good for the job.
Testing several amp and comparing the results like @AaronDC suggested will likely only tell me if there is a difference between them.

I've watched many REW videos and for some reason there is almost zero reference to the amp part of the setup, either to the connections and nor to amp itself.
It's either that everybody is using an analog measurement microphone and an interface, or maybe it's me

 

[Blumlein 88]

Other than FR differences measurements with a USB mic are probably not effected by the amp. As some class D interact with the speakers for non-flat response in the upper frequencies that could be an issue. Distortion measured that way is unlikely to be amp limited unless the amp is too low powered. The other issue is if you want above 20 khz measurements. Most USB mics are running at 48 khz so not going to be useful at higher frequencies. Then again mics that work there are rather expensive. Earthworks for instance make such with extended response for which you'll want to use at least 96 khz.

 

[rokr]

Other than FR differences measurements with a USB mic are probably not effected by the amp. As some class D interact with the speakers for non-flat response in the upper frequencies that could be an issue. Distortion measured that way is unlikely to be amp limited unless the amp is too low powered. The other issue is if you want above 20 khz measurements. Most USB mics are running at 48 khz so not going to be useful at higher frequencies. Then again mics that work there are rather expensive. Earthworks for instance make such with extended response for which you'll want to use at least 96 khz.

O.k. this makes sense and explains why amps are almost no issue when speaker measurements are referenced.