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Planning room eq like this...

tonycollinet

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Using a Mac - so options seem to be more limited.

I've just ordered UMIK-1 direct from MiniDSP.

Which I will use with REW to create FIR filters in Wav format to add to LA convolver in Soundsource, for system wide eq.


I've got a lot of learning to do with REW I suspect. I'm sure I'll be back when the mic arrives for help. But am I missing anything fundamental? Any other approaches which I can take with free/low cost tools on a mac which might give better results.

Thanks
 

Ultrasonic

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At the simplistic level, do you have a microphone stand?
 
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tonycollinet

tonycollinet

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Good point - but I have a small mic stand with tripod mount that I can use with camera tripod. I also expect the topping mini tripod can unscrew the legs to fit to a full size tripod.

Thanks.
 

Ultrasonic

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Good point - but I have a small mic stand with tripod mount that I can use with camera tripod. I also expect the topping mini tripod can unscrew the legs to fit to a full size tripod.

Thanks.

Yes, you can unscrew the little tripod.
 
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tonycollinet

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Thanks - I've been looking for something like that.
 

levimax

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I would use the MMM method much easier and faster than other methods and you get the same results:

 

Ultrasonic

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I would use the MMM method much easier and faster than other methods and you get the same results:

That might depend what is hoped to be achieved with the FIR filters?
 

levimax

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That might depend what is hoped to be achieved with the FIR filters?
Yes if you want to correct phase you can't use MMM but for FR, which most consider the most important thing, it works quiet well and is 95% easier and faster. I am not going to get into the value of correcting phase... it has been discussed to death here.... but even if you want to correct phase down the line I would start with MMM and correcting FR first to learn the tools.
 

Ultrasonic

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Yes if you want to correct phase you can't use MMM but for FR, which most consider the most important thing, it works quiet well and is 95% easier and faster. I am not going to get into the value of correcting phase... it has been discussed to death here.... but even if you want to correct phase down the line I would start with MMM and correcting FR first to learn the tools.

I'm not convinced of the benefits of phase correction either. The OP may feel differently, or wish to experiment though, hence my comment.
 
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tonycollinet

tonycollinet

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Video was interesting - thanks for that.

So - what I'm hoping to fix is some bass boom. Listening room is small - about 9ft by 11ft. I've tamed it (but not cured it) up to now with partial port bungs - but that obviously is not ideal.

I would expect that FR correction would be sufficient for this - particularly as levimax suggested for learning the tools. One immediate question coming from the video - they set up the filters for minidsp. If I want FIR wav files for a convolution AU, what would be the settings for that? I guess generic - would that be correct? And then export filter response as WAV?
 
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Erici

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Since he's just getting started with REW, the OP probably doesn't understand yet the difference between the moving mic and single point measurements. With the single point approach, the mic is mounted on a stand and a sweep measurement in run for one point. This process is repeated multiple times. With the moving mic measurement, the mic is handheld and moved around the listening position to get an average of many points. So in the time it takes to complete one single point measurement, the moving mic method takes 20-40 measurements as an average.
 
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tonycollinet

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Reading above - I'm guessing from comments above, the need for phase correction is controversial? Can you point me at any resources that discuss the pros/cons. Or even just an online flame war would be fine :oops::D
 
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tonycollinet

tonycollinet

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Since he's just getting started with REW, the OP probably doesn't understand yet the difference between the moving mic and single point measurements. With the single point approach, the mic is mounted on a stand and a sweep measurement in run for one point. This process is repeated multiple times. With the moving mic measurement, the mic is handheld and moved around the listening position to get an average of many points. So in the time it takes to complete one single point measurement, the moving mic method takes 20-40 measurements as an average.

Thanks - I guessed that was the case having attempted a sweep measurement yesterday (with inadequate mic). Confirmation helpful though.
 

levimax

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Video was interesting - thanks for that.

So - what I'm hoping to fix is some bass boom. Listening room is small - about 9ft by 11ft. I've tamed it (but not cured it) up to now with partial port bungs - but that obviously is not ideal.

I would expect that FR correction would be sufficient for this - particularly as levimax suggested for learning the tools. One immediate question coming from the video - they set up the filters for minidsp. If I want FIR wav files for a convolution AU, what would be the settings for that? I guess generic - would that be correct? And then export filter response as WAV?

I use REW together with Rephase to create FIR filters (WAV files). There is information online on this. Rephase has a learning curve but I think it is well worth learning how to use as it add a lot of functionality and flexibility when creating the FIR WAV corrections. It also has a lot of phase correction functionality and it is free.

RE: Phase controversy. While the graphs look "nice" for a impulse response if the phase is correct it is believed by most objectivists that phase (within reason) is not audible. Others claim they can hear all sorts of "better" things when the phase is aligned.

RE: Phase practical matters: It is a big PITA to try to use REW to accurately measure phase in a room. There are so many reflections and other issues. You need to take multiple measurements in multiple locations along with "gating" for HF measurements and LF is nearly impossible because you can't use gating. Then trying to measure if you "succeeded" with your phase correction is another huge issue. All in all a difficult process that is hard to verify if it is working correctly with a real chance of making things worse.

RE: Possible phase solution. Since I have DIY speakers I know what type of crossovers I have. One really nice feature of Rephase is that is has "crossover presets" for phase adjustments. You specify your crossover type and frequency and rephase adds a phase correction to the FIR filter "automatically"... it is probably not 100% perfect but to me it seems to work about 90% which since it probably doesn't matter is good enough for me.
 
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tonycollinet

tonycollinet

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OK thanks.

If I can get my bass under control with FR, then that will be good enough for me. I'm not an "expend 90% of the effort for 10% of the benefit" type of person :)
 

Ultrasonic

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Definitely - bass-boom is all about amplitude not phase :).
 

abdo123

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I'm not convinced of the benefits of phase correction either. The OP may feel differently, or wish to experiment though, hence my comment.

Not so long ago you were a strong advocate for aligning subwoofers to mains, what happened?
 

ernestcarl

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E: Phase practical matters: It is a big PITA to try to use REW to accurately measure phase in a room. There are so many reflections and other issues. You need to take multiple measurements in multiple locations along with "gating" for HF measurements and LF is nearly impossible because you can't use gating.

Have you tried using frequency dependent windowing instead of gating when measuring at a distance in the listening position(s)?

Also, maybe save and use your multiple measurements (vector average) of the LF sub by time aligning them all automatically *first (in the all SPL options tab) using REW to get a representative (maybe much cleaner) average phase response -- this you can use to sum later with the mains using the Alignment tool.
 
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