Lot of great comments above...hard to disagree with anything said...(not that my disagreement means anything
I think Danley's and JTR's use of passive crossovers reflects more on the businesses they are in.
Danley appears to have primarily chosen the install market, and large scale at that !
If you were active, where would you want the DSP ?.... up in the sky inside monster boxes with weather and bird poop ?, or down in the warm protected control room ??
Plus, let's say you ditch the passive in-speaker x-overs, for DSP in the control room...
...there are a boatload of drivers in some of those boxes...what happens when some joe blow does exactly that....blows em up from messing with the DSP ?
And then, there's also the fact Danley has a bona fide genius at building passive xovers !
I get the sense that JTR's primary market is home theatre, where customers range from audiophools who 'wouldn't dream of impairing sonic purity with EQ' lol, to guys doing complete loudspeaker control with Dirac room correction or PC convolution...
...so passive suits a widely disparate market.
Just some market speculation....
Anyway, IMO, the biggest advantages for FIR when it comes to sound quality are:
* the ability to embed practically unlimited EQs
* linear phase crossovers
* the ability to use steeper crossovers than with passive circuitry
* the ability to independently alter magnitude and phase
* and as available with any DSP, precise time alignment (as compared to passive)
The only real disadvantage IMO, is latency.
I've kinda come up with a rule of thumb for effective FIR that goes: latency = 125% of the period of the lowest frequency you want to adjust.
So for example, if you wanted to use FIR down to 500Hz, which has a period of 2ms, it will probably take about 2.5ms of FIR time.
This rule of thumb works for up to about 48dB oct slopes. Less slope gets away with less FIR time, greater slope of course needs more.
I mention this rule of thumb because it might help to evaluate what FIR can actually be doing, given published latency specs.....
Maybe someone will knock down my formula, happy to learn a better one, or that I'm full of it !
The ability to embed unlimited EQs is where I think sound quality can be improved on
any box.
I've learned that on a driver-by-driver basis, response variations that occur both on and off axis, are called minimum-phase, and can be corrected with traditional EQs (IIR). These IIR eq's correct both magnitude and phase at the same time together, and absolutely lead to better sound quality IME.
A good traditional non-FIR processor can make these, but how many EQs are in such.
Again, this correction is on each driver, or sections of the same driver, before any xover. Once put together via crossover, minimum-phase no longer holds sway.
Others have already spoken on the value of flat phase and steep x-overs, so I'll leave those alone...other than to say both have been giving outstanding results, with Peter's DIY 90/60, with my own designs, with reworks of kf650z, and with trying active FIR on a JTR 3tx.
edit... I'd like to add a +10 to Kevin's post...
It's hard to overstatement how much easier it is to align and tune, both driver to driver, and box to box, with FIR....
....or more particularly ... with flat phase that comes from the use of linear phase crossovers, and flattening out of band phase (along with the usual out of band EQ flattening)
Whether tying drivers together, or aligning subs to mains (if u can stand the latency)...plat phase ends makes it easy.
And when phase is flat, you can slide x-over up and down a bit, to easily find the best on vs off-axis tradeoffs.
And at least to my ears, it truly does sound better