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Discussion Starter · #1 ·
I'm just reaching the end of the help documents, and I just have a very broad question that will be obvious to most REW users. It's mainly just to do with the whole process. Once good analysis has been achieved, resonances found, EQ filters generated etc. What then? Is the idea that the EQ filters are recreated on whatever EQ unit is in the entertainment system set up? Or is the sound supposed to run through REW? I assume not, but I just don't know. Once EQ filters have been generated, am I supposed to run the sweeps again with the EQ filters affecting the sweep?

Here are my current EQ filters and resonances results: -



:scratch:
 

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REW does not provide equalization so yes, you need that to be done in whatever component you select for this purpose in your system. Room tratments, placement, and seating locaton adjustments can be applied as well. After adjustment to the room and system, you want to test the result.
 

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Discussion Starter · #4 ·
That's great thanks.

Also, I was reading the help document, and it said that even after applying EQ, and getting a visually flat response from REW, it might still sound awful, and that might because of phase - which it suggests is equally as important (or close) as the frequency response.

For me I'd be using REW to get a flatter response in my music studio control room/listening room. I'll probably be able to get the frequency response pretty much flat if I really try - because the music software I use allows any amount of filters to be used. It'd take time but it'd be possible. What I can't alter in the music software is the phase. The help doc suggests that EQ is good from low-mids and lows, but once about 500-1000 Hz, phase will play a more important role, and EQ will no longer be applicable in a valid way. Should I just sort my low-mid/low problems, and leave the mid-high frequency response alone?
 

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> That many filters boosting things will quickly eatup all the headroom available in your speakers amplifier .

> One should use EQ sparingly and when used it's best to cut / not boost .

> To get to the point where minimal EQ can be effective , one wants to acoustically treat their room ( with Bass Traps and Diffusion hanging on the walls ) .

> This is not an Acoustics forum but there are out a couple of good ones out there ( just use Google to find them ).

> I'd recommend buying ( & absorbing as much as possible ) these two books ( before jumping into the deep end of an online acoustics forum ) .
> If one shows up there demonstrating that he or she is a "self-starter", they can usually expect better help from those who are qualified to answer .



:eek:lddude::sn::eek:lddude:
 

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Discussion Starter · #6 ·
Thanks - I have the Master Handbook of Acoustics, but I'll have a look at the other one for sure.

Just another question on the graph. Do you know what the difference is between the blue and grey resonance peaks? And why are some really high up (mainly grey ones)? And finally - I don't know if you can see it on the graph - but the measurement shows a clear trough at around 75 Hz, whereas REW suggests that there's a resonance peak there too. How could this be?

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Do you know what the difference is between the blue and grey resonance peaks?

Off hand , I don't know . ( That's a road I haven't explored very much ) .

But fwiw, cutting frequencies selectively ( as opposed to boosting them ) will reduce those resonances somewhat ( all things being held equal, power-wise ) .

<> EarlK
 

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That many filters boosting things will quickly eatup all the headroom available in your speakers amplifier.
You can't really tell that from the number of filters, need to look at the overall EQ curve (rather than the individuals) to see what the maximum gain is. Bear in mind the graph shows the filters inverted, so the ones above the target are cuts - the boosts are the broader filters below the target.

Just another question on the graph. Do you know what the difference is between the blue and grey resonance peaks? And why are some really high up (mainly grey ones)? And finally - I don't know if you can see it on the graph - but the measurement shows a clear trough at around 75 Hz, whereas REW suggests that there's a resonance peak there too. How could this be?
The resonances drawn in grey are not modal because they decay too quickly (the threshold applied is a 60 dB decay time of less than 200ms). They are often artefacts of the parametric analysis related to the start time of the analysis segment and can be ignored. Resonances can be hidden by nulls or sharp dips in the initial response but become visible later (e.g. in the later slices of a waterfall plot).
 

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JohnM said:
Bear in mind the graph shows the filters inverted, so the ones above the target are cuts - the boosts are the broader filters below the target.

My Bad ! :rant:

> Thanks for pointing that out John .

> If I knew that the filter graph was normally displayed inverted, then I've forgotten that very salient fact .


<. EarlK :sn:
 
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