Yes, the backwards positions definitely look better. Removing the peaks at 60-70 Hz with a PEQ filter or two is easier and better. How will you apply the EQ? Note: If you plan to use REW to compute the filters, you need to get rid of the 1/6 smoothing, which has too low resolution. I recommend Var smoothing, because it has full resolution in the bass. Also, measure both speakers together, L+R, to find the filters. Apply the same filter to both L and R.
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First REW measurements - feedback appreciated :)
- Thread starter viktorapo
- Start date
- Thread Starter
- #42
i would let Neumann's MA-1 system do that job
OK, I see. I'm not familiar with that system, but it seems that it computes all the relevant parameters itself. I'm sure it's fine. Let us know how it goes!
Keith_W
Master Contributor
I can't recall if I put it in my book (and if I haven't, I should). This is how to pick the best frequency response from a bunch of measurements.
Step 1: discard all the irrelevant measurements. I only kept all the "LR" measurements since we don't need to see individual channels. Then align SPL at 1kHz.
Step 2: zoom in to the area of interest and pick two measurements for comparison. Here, it's MLP vs. 60cm forward. The green measurement (60cm forward) is clearly worse, so it's rejected. Why it's worse: the dip is deeper. You will have a harder time filling dips than cutting peaks with DSP.
Continue with each measurement one by one until you are left with the best measurement. In my opinion, your current MLP position is the best.
Another thing. I noticed the measurement SPL was very high (about 105dB). I see you are using an interface, which means you likely did not calibrate the SPL of your measurement so REW's indicated SPL is not reliable. Another way to check if you are measuring too high is to look at distortion. Here, you can see that the THD exceeds 5% (we ignore the bass distortion of 10-20% because of poor SNR). It should be less than 1%. I suspect you are measuring too loud? Please read that book again and note what it says about measurement volume.
I also notice you don't have a microphone cal file. Please obtain one as soon as possible. For this set of measurements, the nonlinear frequency response caused by measuring too loud and lack of cal file does not matter. But it may matter for other measurements.
Step 1: discard all the irrelevant measurements. I only kept all the "LR" measurements since we don't need to see individual channels. Then align SPL at 1kHz.
Step 2: zoom in to the area of interest and pick two measurements for comparison. Here, it's MLP vs. 60cm forward. The green measurement (60cm forward) is clearly worse, so it's rejected. Why it's worse: the dip is deeper. You will have a harder time filling dips than cutting peaks with DSP.
Continue with each measurement one by one until you are left with the best measurement. In my opinion, your current MLP position is the best.
Another thing. I noticed the measurement SPL was very high (about 105dB). I see you are using an interface, which means you likely did not calibrate the SPL of your measurement so REW's indicated SPL is not reliable. Another way to check if you are measuring too high is to look at distortion. Here, you can see that the THD exceeds 5% (we ignore the bass distortion of 10-20% because of poor SNR). It should be less than 1%. I suspect you are measuring too loud? Please read that book again and note what it says about measurement volume.
I also notice you don't have a microphone cal file. Please obtain one as soon as possible. For this set of measurements, the nonlinear frequency response caused by measuring too loud and lack of cal file does not matter. But it may matter for other measurements.
- Thread Starter
- #45
thank you so much! cal file is missing because you mentioned last time that it does not matter indeed for these measurements, and obtaining it is hard, as i am borrowing this microphone from another studio in the studio complex, and its different always. i did plot them like that, thats why i think the backwards positions are a bit better imo
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