Best OB woofer up to 600 Hz?

[Juhazi]

Well as I’ve now decided on the woofers let me take this slightly OT
If I did decide I needed some OB subs (I’m intrigued by the SLOB approach BTW) would I have a problem with latency if I used DSP to filter and EQ the subs but analogue active and passive crossovers for the mains?

Yes the dsp adds some latency, but that shouldn't be a problem for your subs.
However I found a noticable bonus for running also mains through dsp and setting delay for them, xo 80Hz. Then I could also eq the low end of mains (in semi-nearfield) to get better slopes to match my SLPP sub in my HT room. I don't eq room modes at all.

As a fan of closed box subs and dipoles, I am curiously waiting for your impressions with your new system!

 

[Vix]

Hmmm, don't think I've ever seen the Beta 15 on OB. But why not...

Now you did

I have them. They are crossed similar to the SLOB from NP, around 90-100 hz second order , with some EQ. Without EQ, they fade quicky. With EQ, it is OK,but have to be careful with the volume, as with low freq content the cone wants to fly away...
So I consider one 15" driver as the bare minimum for any OB. Now, I'd happily use a pair of 18" (per side)...
Regarding higher crossover point, Beta 15 does not sound good if crossed high; imho, there was too much midrange coming out if it, muddying up the sound. Maybe that's not the case with better and more expensive woofers...

 

[Studley]

Yes the dsp adds some latency, but that shouldn't be a problem for your subs.
However I found a noticable bonus for running also mains through dsp and setting delay for them, xo 80Hz. Then I could also eq the low end of mains (in semi-nearfield) to get better slopes to match my SLPP sub in my HT room. I don't eq room modes at all.

As a fan of closed box subs and dipoles, I am curiously waiting for your impressions with your new system!

DSP is obviously a very powerful and useful tool and I don’t mind using it for low bass. However IMHO it degrades the quality of the signal and I don’t want to use it higher up. So I’ll be using an analogue active crossover.