Home Theater Forum and Systems banner
1 - 3 of 3 Posts

·
Registered
Joined
·
44 Posts
Discussion Starter · #1 ·
Sorry for all the questions....

A quick one now about calibrating REW's internal SPL meter. Here's what I did:

I placed my measuring mic (Rode NT2000) in the listening position. My EMU patchmix was set up like this

Technology Electronic device Audio equipment Electronics Electronic component



so the send in the mic channel is sending the signal to REW.

I then ran the SPL meter cal.... I measured the spl where the mic is (using my Radio Shack SLM) and got a reading of 80dB. Perfect - that's the level I want (prefer that over 75). So I type in 80dB, hit finish, and all is good.

So am I right in saying that the Rode should now give similar readings to the RS SLM? That's the point of the calibration isn't it? Well, I played a pink noise (and white noise) test tone through a channel on the patchmix - and they give different readings.

With both the Pink noise and WHite noise, the RS reads 78-79dB while the REW SPL reads 74dB.

Back to the calibration and they're the same again.

Have I missed something or am I expecting too much accuracy?

Cheers

Max
 

·
Premium Member
Joined
·
1,400 Posts
Max said:
So am I right in saying that the Rode should now give similar readings to the RS SLM? That's the point of the calibration isn't it? Well, I played a pink noise (and white noise) test tone through a channel on the patchmix - and they give different readings.
- When using REW purely as an SLM, its' readout should match that of the RS SLM ( at the same location, etc. etc. )

I then ran the SPL meter cal.... I measured the spl where the mic is (using my Radio Shack SLM) and got a reading of 80dB.
Perfect - that's the level I want (prefer that over 75). So I type in 80dB, hit finish, and all is good.
- That's the correct procedure .

Have I missed something or am I expecting too much accuracy?
Once setup, my REW SLM is dead accurate and always agrees with my RS SLM ( no matter the signal type ) .


<> EarlK
 

·
Premium Member
Joined
·
6,711 Posts
Can you post a screen shot of the REW meter when you are playing either of your pink or white tones, please, to see the settings and levels.

The speaker cal signal is pink noise filtered below 500Hz and above 2kHz so avoids the frequency extremes and hence the regions affected by the meter weighting curves and regions where the mic and soundcard cal curves might have an effect, whilst full band noise signals will bring those into play. The REW meter takes into account the mic and soundcard cal files to generate its result, so you could try clearing those to see if either is having an undue influence on the readings.
 
1 - 3 of 3 Posts
Top