# Help on first time REW measurements.



## secondhead (May 24, 2014)

Hello people

I have just undertaken my first experience of generating a REW measurement graph using a ECM8000 through a RME fireface and yamaha msp5 monitors; In my partially treated room with quite a bit of rockwool in the corners of the room working as bass traps. Here is my listening position first time graph, any pointers on what i am looking at would be excellent, if photos of the room might be good, i'll post some. 

thanks for any comments in advance

wim


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## JohnM (Apr 11, 2006)

You have a bit too much vertical span on that graph to easily interpret it, there are tips on ranges to use for plots in the Please read - posting a graph sticky.


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## secondhead (May 24, 2014)

thanks for the reply, i am currently away from my home studio setup but i have attached the REW file for anyone to have a look at, appreciate any advise.


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## secondhead (May 24, 2014)

OK, here goes again on sending you a workable graph. hope this one is better, i have followed the instructions on the link provided not sure i did anything different from before but here's hoping:wave:


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## secondhead (May 24, 2014)

Just to clarify, this is for my home studio setup. I'm basically looking to achieve the best sound from my mixing position in this room. I guess experimenting with positioning is probably the best thing I can do, as I said before I've got quite a bit of rock wool around the corners of the room but still the dips at 88 and 161 look pretty extreme. If anyone can tell me whether this is a particularly problematic room it would be a great help it sounds ok to my ears but if it can be improved upon. 

I've read a bit about putting eq on your master out to counter the peaks and dips in your REW graph, tell me more people.


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## secondhead (May 24, 2014)

here is a waterfall graph of the decay time in the room from 28hz to 500hz


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## JohnM (Apr 11, 2006)

I guess both monitors were playing at the same time for that measurement? The impulse response has a second peak just a couple of dB lower than the main peak and a very short time afterwards. Having both playing generates a lot of comb filtering at higher frequencies, so best measuring the speakers independently as well. 

Positioning is indeed the best way to go about minimising the dips, one way to quickly try various positions is to use the REW "Pink PN" test signal and look at the response on the RTA using these settings:
 

You can then see the response change live as you move the mic and/or speakers around.


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## secondhead (May 24, 2014)

Brilliant thanks john, yes the test was run with both speakers. Next time I'm at the space I'll certainly do it separately and try repositioning things.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Running both speakers notwithstanding, the limited comb filtering in your frequency response graph indicates very good acoustics, and the waterfall confirms it. Frequency response looks a bit rough, though. However, it’s best to look at full-range response with either 1/6 or 1/3-octave smoothing, to get a graph that’s not so scary and actually looks more like what you’re actually hearing. 

EQ could indeed clean up response, after all location options have been explored and exhausted, especially addressing broad trends (as opposed to chasing every little dip and peak in response. However, EQ should only be applied using dead-accurate measurements, and that requires a mic with a custom calibration file. 

Regards, 
Wayne


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## secondhead (May 24, 2014)

Hi Wayne

Thanks for the response, good to hear that the graph looks reasonable even with the two speakers. Would the generic cal files for the ecm8000 be ok and what minidsp might be appropriate for my situation. Interested to find out more about this sort of thing but I'm not sure if it all might get a bit pricey, might be better off spending money on additional treatment for the room seeing as I'm recording in it also.


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## Wayne A. Pflughaupt (Apr 13, 2006)

The generic ECM8000 calibration file is fine for generating acoustics information and a frequency response graph that gets you a general idea of speaker response. However, as you can see from the picture below, the response of different samples of ECM8000 mics varies considerably in the upper and lower frequencies. With a frequency response graph based on a generic file, you can’t tell for sure where the speaker’s response ends and the mic’s begins.
So you definitely want a custom calibration file if you intend to accurately equalize the speakers.

Can’t help you with a miniDSP choice – don’t know that much about their various offerings. You could probably post a question in our Equalizers Forum and get some opinions from knowledgeable users.










Regards, 
Wayne


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## secondhead (May 24, 2014)

Hi guys, [email protected] back at the studio today.

are a few more graphs, two different listening positions, the second a little further back than the first although admittedly both are pretty close to the speakers..

interestingly overall i prefer the look of the closer position but the further back position seems to work out nicely on the right hand speaker, which is in the corner of the room with a big block of rockwool behind it. might have a go at repositioning the desk adjacent to the corner and try some results..


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## secondhead (May 24, 2014)

hi again, 

just moved the room about a bit and came up with this, hard to know if i've made much improvements. what do you think, better or worse like this? here are some pics of the last test positioning my desk against the corner of the room..

first with both speakers

with left speaker

and with right

:dontknow:


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## secondhead (May 24, 2014)

and with 1/3 smoothing


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## Wayne A. Pflughaupt (Apr 13, 2006)

secondhead said:


> hi again,
> 
> just moved the room about a bit and came up with this, hard to know if i've made much improvements. what do you think, better or worse like this?


No appreciable difference from the graphs from the .mdat file in Post #12.

Regards, 
Wayne


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