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Discussion Starter #1
Hello,

I came across REW and I want to use it to set the sub woofer. I have a Pioneer VSX-2016AVS AVR(7.1 amp). The amp uses MCACC with 9 band equalizer for the all channel except the sub woofer. I want to use REW to setup the sub woofer. I was hoping someone would point me in the right direction:help:. Any help is appreciated

Thanks
VJ
 

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Download REW and play with it a bit in your PC while reading the REW HELP FILES. You'll need an SPL meter and a few cables, that you can sort out by reading the help files. If you have any specific questions - just ask.

brucek
 

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Discussion Starter #3

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Please let have a look at the graph and let me know if they are fine
Yeah, the soundcard cal is fine, but the measure has a small probem (that you can just forget about after I tell you what happened). See how the loopback measurement of the cable isn't perfectly flat? It should be.
That is showing you that you had the meter calibration file loaded (which you wouldn't do, since the cable isn't a meter and doesn't require a calibration file. The result of course is that the response is a mirror of the meter file....

When I set the vertical scale of 0.1dB/division the graph is not symmetrical
I don't know what you mean by that, but the graph scaling is set with the Graph Limits button in the top right hand corner of the REW screen. Use the standard of vertical scale of 45dB-105dB and horizontal scale of 15Hz -200Hz.

brucek
 

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Discussion Starter #5
please comment on the graph. I need to work on those two dips :scratchhead: by experimenting with the placement of the sub. My sub goes down to only 35 Hz. thanks
 

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Don't bother too much with filtering above the crossover.

Raise your level a bit using the trace offset feature (or drop the target) before you create your filters to capture as much of the peaks as is reasonable.

Note: Post graphs with a vertical scale of 45dB-105dB.

brucek
 

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Discussion Starter #7 (Edited)
BruceK

please have a look at the graph and let me know if I am on the right track. The top graph is the sub response. The bottom graph in red is after equalization using BFD. I had a look at your ruler flat curve. I would like to try and get it as flat as possible . I have set the sub channel level in the AVR to +10 db and the BFD in bypass mode does not go to the yellow LED.I have set the BFD -10dbv The pioneer amp(VSX 2016 AVS) has a 9 band advanced MCACC. I dont know if the phase and standing wave control make any difference. I will try to do some more reading with the phase and standing wave turned off.


I ran the auto setup before using REW to set the BFD.

Any help and suggestion is most welcome.


cheers
vj
 

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I have set the sub channel level in the AVR to +10 db and the BFD in bypass mode does not go to the yellow LED.
That's fine. The output levels of many receivers aren't that high, so this is expected.

Any help and suggestion
It's really quite good. You don't need to get it much better than that. You'd find that if you moved the mic a few feet away, it would change at least by as much as the plus minus swing you have now, so it's fine. There's no large resonance peaks left and the only small problem is a dip at ~35Hz. You may be able to move your sub a bit and help that dip.

I guess the next thing is to add the mains and check the integration at the crossover. That's when the phase has an effect. It can be used to smooth that transition area.

brucek
 

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Discussion Starter #9
thanks for your kind words bruce. The green line is with the 2 front + sub and the red is just the sub equalized with the bfd. i have set 80Hz as the xover frequency. I used the following setting to measure the freq response setting.jpg
please let me know if that is the correct setting I used.

thanking you for all your :eek:utstanding: help. :thankyou:
 

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let me know if that is the correct setting I used.
Yep, you can use longer sweeps and increase the number of sweeps to help better the signal to noise ratio of the measure and also to reduce noise and interference. I like to use two sweeps because it averages them and reduces any noise in the room. Just takes longer...

I would like to see the peak at ~100Hz reduced a bit. Try the sub phase and see if that changes at all........

brucek
 
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