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Discussion Starter · #1 ·
I'm just getting REW setup and working. I've got a Dell D410 I've sourced exclusively for REW work. I picked up an external sound blaster to get the appropriate input. I'm using a RS 2050 meter with the HTS provided calibration file. I calibrated the sound card and created a .cal file which I'm using. I'm plugged directly into the sub right now to get the hang of things. I'm planning on doing a before and after to test my room treatments. The room is a non dedicated 11 x 14.5 x 8 and the sub is an eD A7s450.

Here's where things deviate a little.


Using REW pink noise I calibrated the sub level to read ~75db on the RS meter at my listening position. When REW listened to the RS meter (set at 80, C weighting) it read well over 100db. I found a work around by setting the meter to 120 where the REW pink noise didnt move the needle on the RS meter at all. Once adjusted, REW read its input as ~73db. I performed the calibration and ran a 4 sweep, 1m measure. The results I got were much more of what I expected. Here are my second set of graphs.





Does anything here stick out as wrong or seriously out of place? I've spent a lot of time reading the help file, primers and posts so I didnt waste everyones time to answer something thats already documented.

Once I get this down I'll push my filter changes to my BFD and see where that takes me. Thanks for any help.

Adam
 

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When REW listened to the RS meter (set at 80, C weighting) it read well over 100db.
You forgot to run the Calibrate routine to align the REW SPL meter with the actual SPL meter (after you set the input level in the check levels settings routine).

For subwoofer graphs, always use the standard Vertical graph axis of (45dB - 105dB) and the Horizontal graph axis of (15Hz - 200Hz) using the Graph Limits button in the top right corner of REW.

For full range graphs, use the standard Vertical graph axis of (45dB - 105dB) and the Horizontal graph axis of (15Hz - upper limits you desire, i.e. 20KHZ - certainly no higher than your soundcard can extend).
For full range, enable smoothing to eliminate the comb filtering. Use a 1/3 octave smoothing.

For Waterfalls use the standard Vertical graph axis of (45dB - 105dB) and the Horizontal graph axis of (15Hz - 200Hz) using the Graph Limits button in the top right corner of REW.
Set the mode to LOG rather than LIN using the Freq Axis button in the top right corner of REW.
Best to set the time range to 600msec and leave the Window at 300msec.
Set the X=1, Y=50, Z=150.
Select the measurement in the REW left pane you want to look at, and Generate the waterfall.

brucek
 

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Discussion Starter · #3 ·
You know what, I didnt forget. I did it backwards. :wits-end:

I swapped my readings, remeasured and here are my results.





Does it appear correct?
 

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Does it appear correct?
A couple points:

See that floppy icon in the lower left corner of your plots.
Click it and you can save your plots in 800 wide jpg, perfect for posting.

When you click the EQ filters icon, there is a useful up/down arrow icon that sorts your filters from low to high.

As mentioned above for waterfalls... Set the mode to LOG rather than LIN using the Freq Axis button in the top right corner of REW. You have yours set to LIN.

A good practice is to start with the sub alone with the mains shut off (disconnected), so you can see how the sub reacts with your room without any other influence (note the dips at 50 and 70Hz - you don't know what's causing them yet). Then, when you have the sub located and EQ'd the best you can, add the mains and adjust the subs phase to get the best crossover transition.

brucek
 

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Discussion Starter · #5 ·
As mentioned above for waterfalls... Set the mode to LOG rather than LIN using the Freq Axis button in the top right corner of REW. You have yours set to LIN.

Done.



A good practice is to start with the sub alone with the mains shut off (disconnected), so you can see how the sub reacts with your room without any other influence (note the dips at 50 and 70Hz - you don't know what's causing them yet). Then, when you have the sub located and EQ'd the best you can, add the mains and adjust the subs phase to get the best crossover transition.

brucek
Currently I'm running directly from my sound card to the sub. The goal was to remove as many variables as possible to get the hang of REW, then to test the difference my home made treatments make. By then I should have a good handle on the DSP1124 and I'll go ahead and push some filters to it and retest.

Thanks for the help. Any other suggestions?
 

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I think Bruce thought you were showing a full range graph because it's not showing the sloped response you'd expect from a crossover in the receiver.

Try running through your reciever, and then you'll see the sloped response starting at your crossover freq. You'll need to eventually, anyway, and you've proven that you're successfully using the software, so onward and upward.
 

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Discussion Starter · #7 ·
Ok, this cant be right. I just reran the test above and got near the exact same results. I decided to hook up my old sub to see what its response would be and got these.






Old sub is 100w, 12" ported MTX. The sub posted above is 18" sealed eD. Nothing has changed in the room besides me moving the MTX in. All the equipment is in the same place as well as the funiture. I've recalibrated the meter several times, re run the measure several times, even re ran the test on the new sub and got the results posted above.

I'm hooking directly to the sub amps just to see how the sub reacts in the room without being affected by an AVR. Here are two brand new measures taken back to back. Old sub in green, new in red.

 

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The green line isn't an external measurement. It's an internal loopback. You've got something connected incorrectly or a monitor mode turned on.

brucek
 
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