AudioRoundTable.com: Speaker » Mono "flanking sub"

Home » Audio » Speaker » Mono "flanking sub"

Show: Today's Messages :: Navigator :: Polls
E-mail to friend

Re: Mono "flanking sub" [message #81659 is a reply to message #81658]

Mon, 09 November 2015 21:14

Wayne Parham
Messages: 18835
Registered: January 2001

Illuminati (33rd Degree)

You can always provide equalization to fine-tune the response. That sometimes offers additional improvement. But the biggest advantage is from summing of multiple sound sources, which smoothes the sound field using dense interference. That's the point of multisubs, of which flanking subs are a specialized subset. The best performance comes from running both flanking subs and one or two distributed subs.

What you've done is to dial in a single sub. Running it to relatively high frequency and blending it with the mains tends to smooth the self-interference from nearest boundaries, which is using the principle of the flanking sub approach. That's good, but like I said, I think it may make localization a problem on some material. Still, your measurements have shown it to be effective for you, at least for smoothing of the 80-150Hz range, which is the range where flanking subs are most effective.

Report message to a moderator

Re: Mono "flanking sub" [message #81663 is a reply to message #81659]

Tue, 10 November 2015 14:06

jonone
Messages: 67
Registered: October 2015

Viscount

I've dialled in the flanking sub for now as I'm waiting for my sub driver from ae, I was then going to use that nearfield as I'm only using one so I should get the most tactile output.

I was going to run that from the lfe channel with a 60hz crossover so it's not localisable this also means the mains are being relieved of some bass but the flanking sub get high passed at 60hz too, so maybe I should run them full range as I will get better smoothing by having all three overlapping fully? The down side is I may loose some content from the lfe channel, ( did you get to the bottom of that) and I beleive there will be some intermod distortion from the mains although the manufacture has told me only a 100hz and above crossover helps with that.

I have a mountain of a room mode at 40hz, ( you can just see it peaking out in my graphs) the flanking sub helps reduce it, I was thinking the crossover at 60hz will also reduce it as the mains and flanking sub are rolling of, but maybe not high passing the mains/flanking sub and just over lapping the nearfield at circa 60hz will actually help depending on how it sums?

Do you think I can improve the 200hz region or are flanking subs done at 150hz?

Lastly, my nearfield sub will have a sweepable phase knob 0-180, does this effectively do the same thing as delay? Or do I get it as flat as I can with that then try and adjust the delay afterwards?
Thanks again for your help, I appreciate it!

Jon

Report message to a moderator

Re: Mono "flanking sub" [message #81664 is a reply to message #81663]

Tue, 10 November 2015 14:43

Wayne Parham
Messages: 18835
Registered: January 2001

Illuminati (33rd Degree)

I would definitely blend as many sources as possible in the modal region, below 200Hz. Above 200Hz, the sound field is already complex, which is why it is called the statistical region. It is already blended by dense interference from all the mutitude of reflections in the room.

There is a transition region where the sound field is neither densely spaced tiny ripples, nor is it consist of large modes. It's somewhere in between, where the modes are becoming closer together but still apparent, at least in measurements. That is a region that's arguably harder to deal with. One can smooth the transition region with an array of midrange drivers. Even a truncated array can be used to good effect. So if you want to put a helper midwoofer very close to the mains and crossover above 200Hz, that can help smooth that region. It's the same approach as a flanking subwoofer, but closer, perhaps mounted on the same baffle like a 2.5-way loudspeaker.

Report message to a moderator

Re: Mono "flanking sub" [message #81665 is a reply to message #81664]

Tue, 10 November 2015 15:21

jonone
Messages: 67
Registered: October 2015

Viscount

Ok so don't high pass the mains/flanking sub run them "large" and run the nearfield sub from the lfe output at 60/80hz crossover depending on localisation.
I think I can do this if I set the bass out to " both" on my av receiver.
You think this is more useful then theoretically "relieving the mains of some bass"
Thanks, again.

Report message to a moderator

Re: Mono "flanking sub" [message #81666 is a reply to message #81664]

Tue, 10 November 2015 16:21

jonone
Messages: 67
Registered: October 2015

Viscount

Just had a thought, the problem with high passing the mains is the flanking sub gets high passed too, leaving one source below the crossover.
My flanking sub has two inputs that are open at that same time so I could hook up the signal that's hi passed from the mains into one input and the lfe signal into the other input.
Do you think that will work? That way I have two sources below the crossover and the mains get released of bass.
Or is it still better to have four sources of bass below 60hz even there maybe some distortion/ over excursion of the mains.

Report message to a moderator

Re: Mono "flanking sub" [message #81667 is a reply to message #81666]

Wed, 11 November 2015 14:16

Wayne Parham
Messages: 18835
Registered: January 2001

Illuminati (33rd Degree)

For flanking subs to provide smoothing, they need to be blended with the mains, overlapping in the modal range. So run the mains full-range, without a high-pass filter. If the mains are vented, they can optionally have a high-pass set at the Helmholtz frequency, to limit excursion. But do not crossover subs to mains and instead blend them with overlap in the bass. We're not looking for prosound SPL, so over-excursion is rarely a problem with main speakers of any reasonable quality level.

Report message to a moderator

Re: Mono "flanking sub" [message #81668 is a reply to message #81667]

Wed, 11 November 2015 14:38

jonone
Messages: 67
Registered: October 2015

Viscount

Thanks again Wayne, I rarely listen loud to be fair and the speakers go plenty loud enough for me without signs of audible distortion, so your right I don't need pro audio spl!
So full range it is, I will post some more graphs when I get my sub driver and have had time to set it up.
I appreciate all the help!
Jon.

Report message to a moderator

Re: Mono "flanking sub" [message #81679 is a reply to message #81668]

Tue, 24 November 2015 11:01

jonone
Messages: 67
Registered: October 2015

Viscount

Does anyone have problems with male vocals sounding thick at with a 150hz crossover? Should I lower the crossover if this is happening?

Report message to a moderator

Re: Mono "flanking sub" [message #81681 is a reply to message #81679]

Tue, 24 November 2015 12:46

Wayne Parham
Messages: 18835
Registered: January 2001

Illuminati (33rd Degree)

The crossover should be very gentle, like second-order, for best results. With a gradual rolloff like that, we're not really doing low-pass "crossover" to the subs because there is too much overlap. Blending with the mains is the goal. The mains and flanking subs should share the modal range, with the helper woofers gradually rolling off.

When you do that right, you can't even tell the subs are on. They blend seamlessly, and the sound seems to come from the mains. The upper midbass and lower midrange is made smoother than when the subs are off, but other than that (and the added deep bass extension), you can't tell the subs are even present.

Report message to a moderator

Re: Mono "flanking sub" [message #81683 is a reply to message #81681]

Tue, 24 November 2015 14:01

jonone
Messages: 67
Registered: October 2015

Viscount

Thanks Wayne, I'm using the Bessel filter in the minidsp, but I will check unless I changed it and forgot.
It does sound pretty seamless ( almost like it's not on ) in the middle and left hand seat but the right hand seat I thought I could hear some thickness in vocals, the response is more in even at that seat so it might just be a room mode thing? I'm putting the new sub in that corner next to the right hand seat so from past trials it should help with the room modes there.
If not I can always lower the crossover point? See if that changes it.

Report message to a moderator

Pages (9): [ « ‹ 1 2 3 4 5 6 7 8 9 › »]

Previous Topic:	Interconnect cables
Next Topic:	Class d for flanking subs

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Mon Feb 17 03:03:49 CST 2025