High quality, passive, balanced, low pass crossover?

Pet peeve which doesn't really affect the discussion but sealed box and acoustic suspension are not exactly the same thing. Acoustic suspension is a sealed box but with particular woofer and box size relationships. An acoustic suspension speaker is a sealed box but a sealed box need not be acoustic suspension. The old Bozak speakers were sealed box and not acoustic suspension. The famous Advent speaker was acoustic suspension.

If you look at my system page you will see Aerial LR5s as main speakers, plus two Aerial SW12 subs. The LR5s use two 9-inch LF drivers in a sealed box. Acoustic suspension (i.e., sealed box) speakers can provide better controlled bass response with less distortion than bass reflex (i.e., ported) speakers, but they also tend to roll-off more slowly below their -3dB point. The LR5s are supposed to be pretty solid down to about 40 Hz and they actually sound pretty good rolled into the subs that way.

There is usually less distortion (HD) in a ported sub because of less excursion and it is operating in a more linear fashion.

But there is more group delay and phase distortion.

I have been curious about whether relieving the main amplifiers and speakers of trying to reproduce the very lowest bass in the roll-off zone would provide any sonic benefit.

Well 650 wpc is a lot… At say 100 Hz, then amount of power below 100 and above 100 Hz would likely be about the same. So in a more modest system, I would suspect more of an improvement.

I could also accomplish that by using the crossovers built into the SW12 subs, but it would require using two runs of much longer balanced cables.

The length of the XLRs will not likely matter a whole lot,. Unless they have a high amount of capacitance/inductance.

Michael Kelly at Aerial told me simply letting the LR5s roll-off naturally and then rolling in the subs at a relatively low frequency would be a better approach, …

I think that is what I was also recommending with rolling off the mains using a shallow sloped high pass.

Then on the subs one can use something with a steeper slope.


The Vandy system uses shallow slopes and I believe sealed subs? In other speakers they seem to possibly be using folded waveguides, which also are low order. I am not sure of the 2C is using a PR or some folded design… So they are seemingly trying to keep the group delay low and keeping the “order” low… which is needed for phase/time alignment.

So I would be using the Harrison Labs inline RCAS, with sealed boxes.

And with ported or other higher order boxes I would be using digital. It does not take many iterations of hardware to equal the cost of the DSP.

Hence; I would probably just go straight to the DSP as I suspect any magic lost, would be gained with room correction (e.g. Dirac Live). And if the fun did not pan out, then you could likely move it on for not much of a loss.

Their DDRC 88BM (or similar bass management DSP solutions) is something I was looking at a few years ago. And the low freq integration takes a lot work to make it seem like it is almost not even obviously there.

High pass. The Wima caps in the Vandy box ( 5 and 7 ) filters are properly bypassed and also formed by DBS circuit. Many of the Wima cap denigrating sect have never heard them in that combination, eg Vandersteen, Brinkmann, etc.. That’s ok. 

crossover point depends on amplifier input impedance, so the Vandy box filters are designed to accomodate a range of amplifiers. You can adjust using DIP switches, test tones and a voltmeter to “ know “ the -3db down point. Holmz is correct they are first order phase correct filters w Audioquest pigtails in an RFI shielded box.

The 5 box come up used now and then, hold value well. Suggest trying a Vandy dealer to see loaner possible. I would loan you but my 7 amplifiers have built in filter w 128 v DBS.

note the high pass M7 amp is 600 wpc, yes there IS a sonic benefit to high passing your main amp and speakers…

best to you. Let me know how i can help

Jim

Thanks @motokokusanagi - So, in my case where there is plenty of amplifier power (650 wpc), and where the acoustic suspension design and beefy speakers/drivers should not be as susceptible to over-excursion and the resulting distortions (as with bass reflex speakers), it may be better to just let them roll off naturally than to add unnecessary components in the signal path?  I guess if I ever want to try things with a high-pass filter, I can purchase two of the Shure filters for $40 each.  If I don't hear an improvement, I can always use them in my outdoor system.  

I think Kelly is giving good advice here; this method works well for sealed speakers.

The notional benefit of hard high-passing would be to reduce distortion from relieved excursion on the main woofers. In this case, I don't think it would make much sense, or rather, e.g. the Vandersteen boxes, poor return for the expense, plus your amps really don't care that much. No idea what's in those boxes, can see a ton of cheap, stacked caps, but it just seems overall a bit baloney to me, and might be designed to specifically match one of their speakers.

Thanks @holmz for your response.
If you look at my system page you will see Aerial LR5s as main speakers, plus two Aerial SW12 subs.  The LR5s use two 9-inch LF drivers in a sealed box.  Acoustic suspension (i.e., sealed box) speakers can provide better controlled bass response with less distortion than bass reflex (i.e., ported) speakers, but they also tend to roll-off more slowly below their -3dB point.  The LR5s are supposed to be pretty solid down to about 40 Hz and they actually sound pretty good rolled into the subs that way. 

I have been curious about whether relieving the main amplifiers and speakers of trying to reproduce the very lowest bass in the roll-off zone would provide any sonic benefit.  I could also accomplish that by using the crossovers built into the SW12 subs, but it would require using two runs of much longer balanced cables.  Michael Kelly at Aerial told me simply letting the LR5s roll-off naturally and then rolling in the subs at a relatively low frequency would be a better approach, so that is what I have done to this point.  Fortunately, since the subs also have remote controls, I can dial them up or down for certain listening levels and source materials.  Since I have no issues with what I am hearing now, trying HP crossovers would be mostly to satisfy my curiosity.

I like the simplicity of the single value, in-line, crossovers sold by Vandersteen, but would rather cut-off the LR5s somewhere below 100 Hz. I am curious what makes Vandersteen's passive crossovers so different, so much better, and so expensive, given that Shure sells one for $56, or $40 on Amazon?

A first order crossover is pretty easy to make.
The 100 Hz of the M7-HP is probably the 3dB point, and their speakers are usually 1 order crossovers. So they are 6dB/octave.


Another option would be something like a MiniDSP and do the filtering digitally, at least for the LP side. And you could likely have that be steeper than the HP side.

What speakers need a 40 Hz crossover? That seems like it is pretty low. 

Or just get some Harrison labs in-line RCAs?https://www.amazon.com/FMOD-Crossover-Pair-Low-Pass/dp/B0006N41EM