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Sub to woofer XO delay?

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Posted on September 7, 2019 at 21:24:21

andyr
Manufacturer

Posts: 12548
Location: Melbourne
Joined: September 2, 2000

Currently, with a 24dB HP/LP XO @ 100Hz between my subs and my woofers, I have a few ms of delay applied to the woofers (and the other drivers in my main speakers).

Someone has suggested I should reduce the '@ frequency' of my sub/woofer XO - possibly to as low as 50Hz.

As I have a miniDSP 10x10 unit providing my 4-way XO / delays / room EQ - this is easy enough to do.

However, I'd like to know whether reducing the @ frequency between subs & woofers delays the subs more - thus requiring me to increase the delay on my main speakers, to compensate?

Thanks,
Andy

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RE: Sub to woofer XO delay?

Dave_K

08:54:11 09/30/19

RE: Sub to woofer XO delay?

andyr

22:55:24 09/30/19

RE: Sub to woofer XO delay?

John Elison

13:37:47 10/16/19

...

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RE: Sub to woofer XO delay?

Dave_K

08:54:11 09/30/19

RE: Sub to woofer XO delay?

andyr

22:55:24 09/30/19

RE: Sub to woofer XO delay?

John Elison

13:37:47 10/16/19

RE: Sub to woofer XO delay?

jrlaudio

14:48:10 06/14/20

RE: Sub to woofer XO delay?

andyr

14:54:52 10/16/19

RE: Sub to woofer XO delay?

pictureguy

00:33:02 11/01/19

E-Stat

15:34:40 11/18/19

pictureguy

15:48:30 11/18/19

RE: Sub to woofer XO delay?, posted on September 30, 2019 at 08:54:11

Dave_K

In addition to the adjustable time delay in the miniDSP, you should have a phase control on the subs. The time delay and phase adjustments interact. Ideally, the time delay should be used to account for propagation path length differences and any other fixed delays, and the phase control should be used to bring the subs in phase with the woofers at the crossover frequency. So I would set the time delay first, based on distance measurements from the listening position to the subs and woofers: measure the difference between path lengths and then divide by 343 m/s. After you implement the time delay and set the desired crossover frequency, then match phase by adjusting the phase control to maximize output around the crossover frequency.

RE: Sub to woofer XO delay?, posted on September 30, 2019 at 22:55:24
andyr Manufacturer Posts: 12548 Location: Melbourne Joined: September 2, 2000	Thanks, Dave - makes sense. I'll try that out when I get my system back working. (I currently have no Maggie bass panels - as they are in for re-wiring. :-(( ) Andy

RE: Sub to woofer XO delay?, posted on October 16, 2019 at 13:37:47
John Elison Audiophile Posts: 23900 Location: Central Kentucky Joined: December 20, 2000 Contributor Since: January 29, 2004	I have Rythmik Servo Subs that have continuously variable phase. I adjust their phase controls for the loudest bass at my listening position. Then I adjust their volume controls so their loudness is set appropriately for a seamless blend with my main speakers, which operate at full frequency range. My subs' low-pass crossovers are set for about 60-Hz.

RE: Sub to woofer XO delay?, posted on October 16, 2019 at 14:54:52
andyr Manufacturer Posts: 12548 Location: Melbourne Joined: September 2, 2000	Makes sense - thanks, John. I roll off my mains to match the subs roll on! Andy

RE: Sub to woofer XO delay?, posted on November 1, 2019 at 00:33:02
pictureguy Audiophile Posts: 22597 Location: SoCal Joined: October 19, 2008	I leave a GAP between subs setpoint and the low pass from the preamp. So my main speakers, some 1.6s cross maybe 50hz while the sub comes in about 40. The fall / rise is meant to SUM FLAT thru that region. And seems to work. Too much is never enough

Ditto, posted on November 18, 2019 at 15:34:40
E-Stat Audiophile Posts: 37609 Joined: May 12, 2000 Contributor Since: April 5, 2002	With the HT, high pass to Acoustat 1+1s is 70 hz with the low pass to subs is 40 hz. Those values determined empirically via measured experimentation for the most linear results. Along with moving the subs to the rear of the room via Emotiva Virtual Copper. Room also needed some parametric EQ to attenuate a mode.

RE: Ditto, posted on November 18, 2019 at 15:48:30
pictureguy Audiophile Posts: 22597 Location: SoCal Joined: October 19, 2008	I leave a gap between low cut to the mains and hi cut @the sub, too. I removed a little stress from the panels by cutting them at maybe 50 to 55hz while the sub easily works at 40 to 45hz. It sums flat thru the 'gap'. No boominess but DID have to relocate the sub from a corner to get more musicality and better low-end.....without changing any settings. Too much is never enough

RE: Sub to woofer XO delay?, posted on June 14, 2020 at 14:48:10

jrlaudio
Industry Professional

Posts: 76
Location: New York
Joined: November 2, 2012

@John Elison ... Aren't those Rythmik subs wonderful. I use (and have specified for others) those subs for years. I personally use the F12G with the GR Research drivers, since I prefer them for 2-channel audio. It's a subjective thing I admit. They are are a bit taxed in a HT use, but still work quite well on movies.

The ability to set delay and phase is just wonderful. I use APx Analyzers to make those adjustments, not something most people have access to. It's a work tool, so I have them.

As far as setting phase and delay you either have it right or it's not. It's not really a subjective thing. You're phase and time aligned or not. This is why I use measurement for this adjustment. If those parameters are out of alignment even to a small degree, many other things go afoul and become unpredictable, such as overall amplitude response of the system and room mode control. Particularly tangential modes and anti-nodes in most rectangular rooms we find in our homes.

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