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REW for Dummies?


rplace

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I've been reading a lot, watching some videos and poking around REW. I have a Minidsp mic, I got the calibration file. I also used the pink noise and SPL meter to set it to 75dB. When I went to make a room measurement it told me it was way too quiet. I increased the volume over and over till it told me the volume was good for a reading. I had the mic at my listening position and used both speakers. I got the graph below. Thought I was starting to make progress but honestly I'm not sure what to do next. Any advice?

 

!stRoom.jpg.66e38b4d98f50fe366ab168cb3048a00.jpg

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15 minutes ago, Chris A said:

Measure one loudspeaker at a time.  Measuring more than one loudspeaker at a time is like trying to set the timing on two cars at the same time using one timing light.  It doesn't work very well.

 

Place the microphone 1 metre in front of each loudspeaker, on-axis at midrange horn mouth height.  The microphone works a little better when it's looking up at 45 degrees toward the ceiling.  Put as much absorption material down on the floor between the microphone and the loudspeaker as you can, about a metre wide (or wider). 

 

This will help you to capture phase information so that you can use that information.

 

Chris

 

In reading a bit....but I'm sure you know way more than me....I got the feeling that type of measurement was for measuring the speaker, as if you were a speaker builder, or testing one speaker vs another. Don't I want to measure for lack of a better phrase, everything? That is the room and my speakers as a whole so I can make it as flat as possible where I am sitting?

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7 hours ago, babadono said:

Thanks for this. I'm trying to get going with this. It is really hard for me to spend time in the summer doing this.

 

Agree about summer time. I swore this two-way active set up was going to be a fall project but I keep trying to see a bit of what can/should be done.

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While not REW specific this is a decent overview of what the goal is and how to approach it. https://support.biamp.com/General/Audio/Equalizing_loudspeakers_in_a_sound_system pretty basic but worth a few minutes if you are just starting out.

 

Also starting on page 60 of the link form @weziewoo There is some good info on how to make your reading more readable.

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6 hours ago, rplace said:

 

Agree about summer time. I swore this two-way active set up was going to be a fall project but I keep trying to see a bit of what can/should be done.

Your vertical scale and range is too high at 10 db. Not enough resolution. You need to lower down to 5 db steps or less by limiting the total magnitude range.

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53 minutes ago, ClaudeJ1 said:

Your vertical scale and range is too high at 10 db. Not enough resolution. You need to lower down to 5 db steps or less by limiting the total magnitude range.

 

Reading a bit more I applied a 1/6 smoothing (not sure what that means) then set the left/right/top/bottom range. Is that what you meant @ClaudeJ1 ? I'm still quite new to all this. Below looks a bit more like others I've seen. I also ordered a boom mic stand so I can take individual speaker readings like @Chris A suggested. I'll check the differences between each speaker and the room to try and get a better feel for what is happening where.

 

Any advice or suggestions greatly appreciated.

 

OneSixthSmoothing.jpg.e28de948dac0ad902a53ab9d8e10701a.jpg

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If I remember correctly, smoothing = masking certain ups and downs in which certain frequencies may or may not be (noticeably) impacted. Sort of a vague idea, sorry.

 

For the overall range of, say, 20hz-20khz, you would apply a certain smoothing, for just your fronts, center, subwoofer, etc, another...

 

But I think it has to do with what are you looking for in the graphs? I remember measuring my subwoofers and the scale was something like 5-120hz, but was also told to increase to 300hz because of how it would blend with the other speakers.

 

Quite frankly, I ended up storing my Umik-1, uninstalling REW, and simply enjoying my speakers. I was getting too obsessed with all that, but there is a plethora of knowledge in that guide, allowing you make you system sound better***

 

***depending how much effort you want to put into it 🤪

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47 minutes ago, weziewoo said:

Quite frankly, I ended up storing my Umik-1, uninstalling REW, and simply enjoying my speakers. I was getting too obsessed with all that....

 

I often go back and forth between settling where I am and just listening to music or to keep chasing the next whatever.

 

As for the smoothing, I though my original looked somewhat flat. Once you get the top/bottom/right/left set it has a lot more ups and downs.

 

Am I correct that mine has roughly 105 to 135dB (30dB) swing based on the left, vertical numbers and the high/low of my readings of my red line? Am I further correct that as "flat response" would be one where the difference is only +3dB and -3dB? So the goal is to tame back those peaks?

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4 minutes ago, rplace said:

 

I often go back and forth between settling where I am and just listening to music or to keep chasing the next whatever.

 

As for the smoothing, I though my original looked somewhat flat. Once you get the top/bottom/right/left set it has a lot more ups and downs.

 

Am I correct that mine has roughly 105 to 135dB (30dB) swing based on the left, vertical numbers and the high/low of my readings of my red line? Am I further correct that as "flat response" would be one where the difference is only +3dB and -3dB? So the goal is to tame back those peaks?

 

From personal experience, perfectly flat graphs usually result in somewhat "boring" sounding speakers. But this is such a tricky and touchy subject, because each and every one of us thinks/hears certain speakers sounding "better" than others. I like extra oomph depending on what I'm watching/listening to, so a house curve is mightily recommended (and fun to play with!)

 

This is an interesting read: https://www.stereophile.com/reference/book_review_isound_reproduction_loudspeakers_and_roomsi/index.html

 

Also, Floyd Toole is a well of knowledge, his articles, books and papers are insanely good.

 

As far as the ups and downs in your graph, I wouldn't worry too much about them because I don't think you can measure a flat, native response from any speaker unless you are in an anechoic chamber.

 

Lastly, if you have about 75 minutes to spare, this is absolutely worth watching:

 

 

 

Cheers

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14 minutes ago, rplace said:

 

I often go back and forth between settling where I am and just listening to music or to keep chasing the next whatever.

 

As for the smoothing, I though my original looked somewhat flat. Once you get the top/bottom/right/left set it has a lot more ups and downs.

 

Am I correct that mine has roughly 105 to 135dB (30dB) swing based on the left, vertical numbers and the high/low of my readings of my red line? Am I further correct that as "flat response" would be one where the difference is only +3dB and -3dB? So the goal is to tame back those peaks?

If you can get +/-5 db at your seated position with 1/3 octave smoothing, you are better than average.

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