# Audyssey and Sub EQ



## sportflyer (May 2, 2010)

I am quite happy with the intergration of the SUB with the mains speaker for 2 channel Music in Stereo mode. I used REW to EQ the sub with no house curves .

Should I rerun Audyssey Calib for HT? 

I have 2 followup questions:

Suppose I rerun Audyssey with one FD EQ filter set ( no house curves) between AVR and Sub

a) Would Audyssey EQ be seriously affected if I subsequently substitute another set of BFD EQ filter with a house curve ? I ask because I find that Moves sound much better with a house curve 

b)For 2 channel listening in stereo mode, can I assume that if I turn off Audyssey , there will be no Audyssey correction to what I have done for 2 channel listening? 

Tks


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## fusseli (May 1, 2007)

I would try running Audyssey, why not? I would definitely take sweeps in REW at multiple listening spots and see how much it does or doesn't help. I would think that if you run it on top of your BFD EQ, that you might be able to get a little bit better. I'm suspicious of latency/phasing issues with processing your data twice, though...

Ya, most receivers have a pure/direct/stereo mode that bypasses all processing and just outputs straight to the amplifier.


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## crom0123 (Feb 14, 2012)

Hi,

I've got the best results running Audissey first and applying BFD's filters and house curve on second step.
Details:
-Run Audissey first; BFD is ON and in bypass mode (led blinking) so that Audissey take into account the delay introduced by your BFD
-Make a SUB only measurement using REW; Audissey is ON; BFD is ON and in bypass mode;
-Apply the desired house curve and EQ the sub to smooth the peaks
-Make another measurement of the 2 mains and the sub together

Cheers!
crom


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## sportflyer (May 2, 2010)

I use nearly the same process as your method above. I don't use Audyssey for 2 ch listening , I do use Audyssey for HT.

My process is as follows:

1) Run Audyssey ( 3 positions only ) with BFD in Bypass mode to get the relative speaker distances and the Speaker levels matched.
2)Turn Off Audyssey , set Rcvr in Stereo mode , main speaker Xover to 200hz and run a subwoofer only scan with REW ( BFD in Bypass mode) then EQ to 200hz for smooth response.
3) Apply the filters to BFD and rerun subwoofer scan to check for accuracy of filters.

The reason for running Subwoofer scan and EQ with mains Xover at 200HZ is so I can the set the main speaker Xover subsequently to any value I want that is lower than 200HZ. 

4) I now set the main xover to 80hz , 100 hz and 120 hz and run the full freq Scan from 20hz to 5Khz for each Xover setting and see which ones gives me the smoothest response. Also do listening tests for each of the Xover. Sometime a small tweek of the subwoofer phase will smooth out the response.

I write down all the settings for 2 ch listening. Currently I am using 100HZ Xover.

For HT , I repeat 2) and 3) with a house curve ( normally use 4 db/octave from 120hz ) . I store the data in a different BFD filter set .

Now I rerun Audyssey with all 8 positions with the HT Filter set activated.

Then I recheck the speaker distances and levels with the original 3. Most of the time they are the same.


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## fusseli (May 1, 2007)

^ that's an interesting and involved approach and I don't doubt that you get a decently flat FR. My concern is phase issues of adding one set of filters on top of another set of filters (flat FR is half the battle). Phase delays are frequency dependent and will change for each new set of filters you let Audyssey or REW make (neither use symmetric FIR filters). For this reason, having the BFD in bypass has nothing to do with the phase introduced by a particular set of filters it may later be implementing. This will obviously only concern the bass region below your xover setting. I'm wondering if adding together your two sources of room correction won't have some interesting effects on how flat your FR is at multiple locations (phase issues). Especially since you will be using REW/BFD from a single measuring spot vs. the voodoo that Audyssey tries to do with managing multiple listening spots.

Hope that makes some sense :scratchhead: it'd make more sense to me to solve for one set of filters, then solve for the next batch with the others already in place. That or keep either set independent of eachother, somehow using your crossover point to divide the two.


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## crom0123 (Feb 14, 2012)

I tried to use BFD's EQ first and Audissey after but Audissey alters my house curve.
Attached is my FR, waterfall and spectogram ,taken at the main listening position. I used only 3 filters on BFD without any boost. I measured the FR at the other main 2 seats, left and right of main position and they are very close, within 1-2db. My system sounds much better now :T. There is plenty room for improvement of course, I'm still educating myself in this field.
Thanks John M. for making REW available for us.:T:T:T


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## sportflyer (May 2, 2010)

fusseli said:


> ^ that's an interesting and involved approach and I don't doubt that you get a decently flat FR. My concern is phase issues of adding one set of filters on top of another set of filters (flat FR is half the battle). Phase delays are frequency dependent and will change for each new set of filters you let Audyssey or REW make (neither use symmetric FIR filters). For this reason, having the BFD in bypass has nothing to do with the phase introduced by a particular set of filters it may later be implementing. This will obviously only concern the bass region below your xover setting. I'm wondering if adding together your two sources of room correction won't have some interesting effects on how flat your FR is at multiple locations (phase issues). Especially since you will be using REW/BFD from a single measuring spot vs. the voodoo that Audyssey tries to do with managing multiple listening spots.
> 
> Hope that makes some sense :scratchhead: it'd make more sense to me to solve for one set of filters, then solve for the next batch with the others already in place. That or keep either set independent of eachother, somehow using your crossover point to divide the two.


Basically when I listen to music , I turn off Audyssey and use one set of BFD filters with mains XO=100hz or 120hz. 

When I watch movies , I turn on Audyssey and use a second set of BFD filters with mains XO=100hz


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