Stereo or Mono Subs Xover at ~100Hz

[KaffiMann]

Then your solution is IB.

 

[scottjoplin]

I've been experimenting with an IB push-push sub in the wall between lounge and hall, that works very well, the ultimate in many respects

 

[KaffiMann]

And then you can brag about having the biggest system. Heated debate at the pub: "You think you have a big stereo system? Hah! I LIVE INSIDE my sub!"

 

[scottjoplin]

........and then I'll add a Swarm........

 

[KaffiMann]

... You lost me there.
Are we talking about the collective motion of a large number of self-propelled entities?

As in everyone left the pub to party inside your subwoofer?

 

[poseidonsvoice]

Now you’re talking. A swarm of infinite baffles. Or a double bass array.

Best,
Anand.

 

[scottjoplin]

Yes, looked into that too, and active absorption, it's never ending, perhaps I will more outside, no, hang on, there's only me to please in my one listening spot, this makes things much easier?

 

[KaffiMann]

It's friday. Let room modes outside the listening spot be left to themselves.

Better get a beer, put on some good tunes and "get your smug on".

 

[scottjoplin]

I've been asking too much of my Eikonas, I'm experimenting with 12dB/oct, still at 100Hz for the time being, sounds smoother, better between 100-200Hz. Using the Bessel at the moment, I've been reading up about it, evidently it's not easy to implement as a high pass analogue filter, I presume that isn't an issue done digitally?

 

[KaffiMann]

Bessel works really well for me with DSP.
Try a 3rd oct or 4th order LR HP at 160-190hz, with 2nd order bessel LP at 100-120 or thereabouts. Toss in some butterworth to compare.

Mix'n'match, it is quite interesting. Bessel + Butterworth can work very well.

Edit:
Over ca 7-900hz I keep coming back to 2nd order Bessel HP+LP, time and again. Especially for coaxials. Below this freqency range nothing is sacred, everything can work if matched well. I personally prefer to avoid filters sharper than 8th order.

 

[KaffiMann]

How's it going?

 

[scottjoplin]

Hi, I'm using 4th order Bessel now LP and HP at 100Hz. Subs in stereo again due to larger overlap. I did try 2nd order but had problems with the cavity resonance again. The region 100Hz to 200Hz is a lot flatter and sounds punchier

 

[KaffiMann]

Have you tried comparing filter types?
And if you use 2nd order bessel on the subs you should go 3rd or 4th order high pass at 140-180hz somewhere. I think it is a bit backwards to call it a cavity resonance, because there is nothing in the cavity causing any resonance, but merely the cavity combined with panel lengths that actually starts being effective. It is not a curse, it is something to take advantage of.

Glad to hear you are happy with stereo subs, I think it makes a difference.

 

[scottjoplin]

Have you tried comparing filter types?

Subjectively I can't hear much difference with types, just a smoother transition with order.

And if you use 2nd order bessel on the subs you should go 3rd or 4th order high pass at 140-180hz somewhere.

Why, wouldn't that leave me with a large hole?

I think it is a bit backwards to call it a cavity resonance, because there is nothing in the cavity causing any resonance, but merely the cavity combined with panel lengths that actually starts being effective. It is not a curse, it is something to take advantage of.

It's commonly called cavity resonance, I understand it is a short TL, so it is a resonance.

Glad to hear you are happy with stereo subs, I think it makes a difference.

It's definitely better at the slopes I'm using

 

[KaffiMann]

...
Why, wouldn't that leave me with a large hole?

...
It's definitely better at the slopes I'm using

No hole. Because the rising response of the subs will contribute up to a point, and be flattened out against the filter. Then the roll off from the filter catches up and this is often a good transition point to xo.

Active filter solutions are great. so much to play with.