Some doubts taking first measurements

[jjos1]

Hi everyone.
I'm an electronic music producer and I'm really interested to learn more about room acoustics and measures which brings me to this marvelous software and forums. On the last days I've been navigating and watching some videos about REW and how to make measures but I see that depends on the person the process is slightly different.

As I always share house and living renting, most of my work was done using high end headphones and adapting my listen to the modes of my room. But for first time I have my own space and make some kind of acoustic work is possible.

My setup consist in a pair of Genelec 8010A with a Genelec 7040A subwoofer.

In some places I read that the measurements needs to be done at the main point of listen and close to it and using the whole setup which have sense for me as It will be the real using scenario but in other posts I see that the measurements are done using the subwoofer only and the positioning the microphone on the opposite corner of it.

I would like to have some help to get the most reliable data. I will be reading and ivestigating more but I would aprecciate suggestions, articles or any kind of help.

Thanks in advance.

Jos

 

[sm52]

In some places I read that the measurements needs to be done at the main point of listen

The sense of improvement is for the place of listening. This way you can get the best result. This is your option. Another case is when you need to get an improvement in many places in the room. I don't think this is your case.

 

[DanDan]

Measurements are most useful if they are done for a purpose. A Sub in one corner and the Mic at the opposite corner will stimulate and receive all the modes. All modes end up in the corners. The sound at the Listening position can be optimised by trying different locations for the Listener and the Speakers. Measuring the response will find the optimum response much quicker and more certainly than just listening and trying to remember how the previous positions sounded.

 

[JStewart]

In some places I read that the measurements needs to be done at the main point of listen and close to it and using the whole setup which have sense for me as It will be the real using scenario but in other posts I see that the measurements are done using the subwoofer only and the positioning the microphone on the opposite corner of it.

Yes, measure at the listening position.

To expand upon DanDan's advice, you possibly could also put the sub in the listening position and put the microphone at the various places where you could place the sub to check the response at the various locations. With either method, this is the first step to EQ with a subwoofer.

Some general EQ guidelines are:

- EQ only the low frequencies up to approx 300 to 350Hz. (i.e. Schroeder Frequency or Transition Frequency)

- Use EQ to remove the peaks but not fill the dips. You can't fill a true null with EQ. We are less sensitive to hearing dips than peaks. Headroom will be used to when boosting and may cause clipping if not accounted for elsewhere in the signal chain.

- For the mains you might consider measuring for EQ with the "Moving Mic Method"

- IIRC the Genelecs have excellent dispersion characteristics and as a general rule one would not want to EQ above the Schroeder Frequency anyway. However, you may wish to use a shelving filter to adjust for tonality.

 

[DanDan]

Interesting. I have seen references to the MMM, but never had it displayed until now. I don't think it is a good idea. Sonarworks also recommend holding the mic in the hand.... also No No from DD

 

[Wayne A. Pflughaupt]

I’ve heard of MMM to but this is the first time I’ve seen it demonstrated, too. I’m curious if they had both left and right speakers playing during the measurement - seems like that would generate some phasing abnormalities that could affect the results.

I guess the best thing to be to A/B test the EQ results from both MMM and the traditional single point.

Regards,
Wayne

 

[JStewart]

Interesting. I have seen references to the MMM, but never had it displayed until now. I don't think it is a good idea. Sonarworks also recommend holding the mic in the hand.... also No No from DD

Good point. Need to minimize unwanted noise by not changing grip on the mic while measuring an not letting the mic cable drag on or hit anything.

I’m curious if they had both left and right speakers playing during the measurement - seems like that would generate some phasing abnormalities that could affect the results.

Here’s an example:
Post in thread 'REW-Moving Microphone Method Help'
https://audiosciencereview.com/foru...ving-microphone-method-help.12641/post-376624

 

[DanDan]

Next time I fire up the studio I might record a spectrum of the noise generated by the muscles and cable and the substantial rumble of air. The little foam poppers are nowhere near enough to suppress VLF air on diaphragm noise. Whatever about YouTube Influencers making up nonsense based on a previous and now superseded building acoustic practice, it is somewhat shameful IMO for Sonarworks to recommend hand held sampling.

 

[Wayne A. Pflughaupt]

The little foam poppers are nowhere near enough to suppress VLF air on diaphragm noise.

I expect they may say the signal from the pink noise signal would be loud enough to swamp any noise from air movement and therefore render it a non-issue.

Don’t get me wrong, I’m in your corner - just surmising how they may reply to this concern. I have my doubts MM will get better results than a standard single-point measurement.

IMO people fret over this stuff way too much. Did you see the charts in Post 29 at the AV Science thread @JStewart linked? Dude's miniDSP plastered nine filters to a curve that needed only three at most. I mean, c’mon.

Regards,
Wayne

 

[DanDan]

The Sweep Measurements are quite immune to noise. But proximity to the body will still cause a big anomaly. Dirac Live uses 9 locations, but afaik allows one to add more. Sonarworks uses 29.