# How do I calibrate/set "distance/delay" for DUAL subs at NON-SYMMETRICAL positions???



## deepstang (Nov 17, 2009)

Initially I had my dual Epik Sentinels on both back corners of the room (actually the left side is not a true corner as there is only one wall and 1" of another). I had HUGE room nulls, and realized when I pushed the true corner loaded sub 10 feet forward that my REW graph was much better and the huge 25-35 Hz null was largely fixed.

I realize that just becuse I have a good REW graph doesn't mean that I have my subs properly dialed in. The problem that now occurs is that I need to set the appropriate distance/delay for the subs....and with duals at 2 different distances from the LP and walls, I am not sure what to do. 

My current receiver is the Onkyo 605 with Audyssey 2eq (no sub filters). I don't have a BFD yet, but was thinking that the DSP1124P would be my best option to further smooth out my response. Now that I have the subs at different distances, I am not sure if i should consider something else. Any help/advice would greatly be appreciated!!


----------



## deepstang (Nov 17, 2009)

Someone recommended:

http://www.behringer.de/EN/Products/DCX2496.aspx

Seems intimidating!!!


----------



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

Yes, it’s going to require either a digital speaker processor like the DCX, or a separate digital delay unit (which means yet another box in your system). 

A good alternative that might be both cheaper and a bit less intimidating would be a vintage digital equalizer. Many pro audio companies offered them previously to introducing the speaker processors (which rolled EQ, delay, compression and crossover functions into a single package). You can find several listed in the “BFD Alternatives” sticky thread in the BFD Forum. Keep in mind that the digital EQs may or may not include a delay function, so do your homework before buying one.

Regards,
Wayne


----------



## deepstang (Nov 17, 2009)

*Situation:*


> Initially I had my dual Epik Sentinels on both back corners of the room (actually the left side is not a true corner as there is only one wall and 1" of another). I had HUGE room nulls, and realized when I pushed the true corner loaded sub 10 feet forward that my REW graph was much better and the huge 25-35 Hz null was largely fixed.
> 
> I realize that just becuse I have a good REW graph doesn't mean that I have my subs properly dialed in. The problem that now occurs is that I need to set the appropriate distance/delay for the subs....and with duals at 2 different distances from the LP and walls, I am not sure what to do.
> 
> My current receiver is the Onkyo 605 with Audyssey 2eq (no sub filters). I don't have a BFD yet, but was thinking that the DSP1124P would be my best option to further smooth out my response. Now that I have the subs at different distances, I am not sure if i should consider something else. Any help/advice would greatly be appreciated!!


*Update:*
So, 6 months back I bought a BFD 1124p, used REW and had pretty good results.

http://www.avsforum.com/avs-vb/showthread.php?p=18097407#post18097407

Even though the graph looked pretty good, I can still hear the inaccuracy in the bass. I attribute that to the staggered, non-symmetrical placement within a room that has 2 large opening to other rooms.

I am planning on reading up on the new Beta REW and give that a whirl. I wanted to ask if the 1124p can set individual delays to each sub, and if the new BETA version can further help my situation. Thanks.


----------



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

The BFD has no delay provisions. That will require a different equalizer. I think REW does have a feature that determines distance/delay, but I’ve never used it. Perhaps John can comment.

Regards,
Wayne


----------



## JohnM (Apr 11, 2006)

If you connect a loopback on the left channel and tell REW to use that as a timing reference (on the Analysis preferences page) you can see absolute timing to allow separate measurements to be compared, REW will also estimate the arrival time and show it as "System delay" in the measurement Info window, but time delay info for subwoofers can be inaccurate due to their limited bandwidth. A tape measure gives more accurate distance measurements to use for sub delay settings


----------



## atledreier (Mar 2, 2007)

Do you have any idea how Audyssey measures delay? Chris at Audyssey says they use low frequency information to measure delay.

semi-OT: with the loopback, can you get absolute phase of the impulse to check wiring polarity errors?


----------



## lesmor (Dec 30, 2009)

Have you considered a SVS AS-EQ1 SubEQ this can handle dual subs and calibrate their delay times, not cheap though.
Or perhaps a Anti-Mode 8033 Automatic Subwoofer Equalizer which is a lot cheaper
I have been told the antimode is a fantastic piece of kit ,I think it can be used for duals, but confirm before buying


----------



## deepstang (Nov 17, 2009)

Even if a tape measure is used, I wonder what the easiest route would be for me to apply individual delay. I have Audyssey 2eq, which has no sub eq; however, it does set the distance for 1 sub. Unfortunately, that doesn't help my staggered set-up. The more advanced Audyssey is awesome and does correct polarity issues by setting the correct absolute phase.

The SVS as-eq1 is a great produce; however, you are correct in that it is almost $900:unbelievable:. The Antimode-8033 is probably the best sub-eq for the time and money; however, it only sets distance and delay for 1 sub. I have read of many users with 3-4 subs use the Anti-mode with great success. In my situation, I am blaming (thus my opinion) the slight inaccuracy and bloatiness of my bass on the lack of proper delay and calibration to each sub.

Getting a fancier receiver with MultEQ XT and power processing (like the 9.2 Onkyo 1008) would also pink and set individual delays and calibration to each sub. The as-eq1 rocks because it first pings the subs individually, than together as a system.


----------



## Kal Rubinson (Aug 3, 2006)

lesmor said:


> Have you considered a SVS AS-EQ1 SubEQ this can handle dual subs and calibrate their delay times, not cheap though.


Yes but the OP has no way to set those delays independently.



> Or perhaps a Anti-Mode 8033 Automatic Subwoofer Equalizer which is a lot cheaper
> I have been told the antimode is a fantastic piece of kit ,I think it can be used for duals, but confirm before buying


It cannot distinguish between the two outputs and has no provisions for delay/level.

To me, it seems as if the best bet might be to buy a new AVR with Audyssey MultEQXT32 and Sub EQ HT. All the features in one box.


----------



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

deepstang said:


> Even if a tape measure is used, I wonder what the easiest route would be for me to apply individual delay. I have Audyssey 2eq, which has no sub eq; however, it does set the distance for 1 sub.
> 
> The SVS as-eq1 is a great produce; however, you are correct in that it is almost $900:unbelievable:. The Antimode-8033 is probably the best sub-eq for the time and money; however, it only sets distance and delay for 1 sub.


Most pro digital EQs have provisions for digital delay. The most economical options are older ones that are discontinued, like the Yamaha YDP2006.




> In my situation, I am blaming (thus my opinion) the slight inaccuracy and bloatiness of my bass on the lack of proper delay and calibration to each sub.


I seriously doubt the bloated problem is delay-related. Most likely it’s an EQ issue. Graphs showing the subs’ combined response, and the subs + mains, would probably tell us what we need to know.

Regards,
Wayne


----------



## JohnM (Apr 11, 2006)

atledreier said:


> semi-OT: with the loopback, can you get absolute phase of the impulse to check wiring polarity errors?


You always have absolute phase info available by looking at the % FS view of the impulse, loopback or not. For checking individual wiring polarity you would need to take care to limit the sweep bandwidths to fall within the range of each separate drive unit.


----------



## Harryup (Jan 29, 2007)

My experiences says that a tape measurement is not sufficent.
The peq used might delay differently due to how much processing is used in each band and you could also have a consirable group-delay. Is there a "better" way to measure than using the impulse-response and compare the different bands? If the woofer is hard to measure could not a for the measurment extended bandwith be useful to get a better signal to noise ratio in the subs?

/Harry


----------

