Active vs passive crossover

@fiesta75, can you install in-line fuse to the wire if you concern about it?  Might need to be selective with the quality of fuse and holder.  I have not tried it but some people bypass the fuse in the passive crossover and get the speakers to sing with more clarity treble and tighter bass. 

Passive crossovers can get pretty expensive, so I'm not sure how much of the decision comes down to cost with the higher end speakers.  Passive crossovers give the manufacturer full control of the crossover interaction once the speakers get into the end users hands....not so much with an active crossover.  

In term of the cost and simplificity of the architecture, I respectively disagree with the passive crossover system is the lesser of the dual when it is applied in the industry. Think about it, the active crossover/DSP/EQ unit has been multi-channel ready and could house, say, 3-way (6 channels) plus subwoofer, in one-box IF the internal DAC is in Hi-Fi quality. This will eliminate the need for the multi-channel DAC module. Also, as an additional benefit, the DSP/EQ module enables one to perform room acoustic correction.  You would need purchase and add that into the passive system.

When it comes to amplification, the multi-channel PAs can be customized based on the customer’s need just like Emotiva does. Even you have preferences in terms of selecting different PA for each signal frequency spectrum, the power requirement of each P.A. would no longer necessarily be as needy and costly as a single PA serving the full-range frequency. For example, a good 20-30 watts PA should suffice to drive tweeters (2/5kHz - 20 kHz) to sing sweetly. A good 50 wpc and >100 wpc class A/B or D should be prenty to drive midranges (200Hz-2/5kHz) and woofers (40Hz-200Hz). The amplication modules do not need to be manufactured by the venders and, instead, purchased by the individuals to their satisfaction as long as they meet the specification. Note that, in today’s high-end Hi-Fi world, it is quite common that audiphiles purchase expensive monos or multiple stereo amp of enormous power to support their full-range speakers already.

Finally, when it comes speakers, as you know, they just need to be wired directly from the PA at the multiple terminals. If you are concerned about lack of protection then adding in-line quality fuses to the wires or terminals should resolve the issue. Therefore, overall, I really do not think the active crossover system will necessarily be more costly or complex than the passive couterpart. It is just the matter of taking paradigm shifts in concept, implemention and business models to make it reality. I am confident that, if you build it, "they" will come.

All fuses degrade sound. You never want a fuse in series between the amplifier and speakers, ever.

@erik_squires wrote:

These [A/D to D/A conversion] are 2 new steps which must be introduced into the chain for active digital crossovers. Question is, how do I evaluate the sound quality of each step and decide if I like it? Well, I have to listen to the finished product.

With a few decades of experience listening to a variety of great measuring DAC’s I know that some great measuring DAC’s sound like crap.

On paper, if all sounded great, and all A/D and D/A steps were perfect then the active digital crossover offers a number of advantages vs. passive but it’s not necessarily simpler.

My take is you’re complicating matters unnecessarily here. Quite a few factors determine the sonic outcome and differences on the active side vs. a passive system, but to me it simply comes down to one listening scenario (active) vs. the other (passive).

Comparing the same pair of speakers (indeed a variety of speakers in a range of setups) going from being passively to actively configured, the outcome to my/our ears has always been in favor of the latter - by a wide margin. I’ll spare you the details in perceived sonic differences though and instead cut to the chase: who cares if the A/D to D/A conversion in the DSP unit used isn’t "perfect" when what’s served in the end is the better sounding meal?

You can avoid the A/D to D/A conversion with a digital input, of course, having only the D/A conversion to worry about in the DSP, but the same applies: which scenario sounds better on the whole, speculations about the detrimental effects of conversions and other be damned?

If a less optimal DSP (bad converters or whatever) still pulls off the trick, then going further with a better DSP is just a bonus, and yet for some reason active has to be "perfect" in all of its implementing steps for many to even consider it, while forgetting all along that passive configuration is hardly perfect itself - far from it, in fact.

Now I must deal with multiple amplifiers per speaker. Does the speaker maker pick those? Do I?

Fortunately active config. means amps are less important and less distinguished when presented with an easier load sans passive cross-over, performing much closer to their full potential and also making more effective use of their power envelope. Which is also saying that the choice of amps is less critical with active config. than it is with passive speakers.

If in doubt use the same amps from, say, 100Hz on up, and wait to be surprised how well even very cheap amps sound actively configured. If you have simple, 2-way stand-mounted speakers and two different stereo amps lying around, try it out actively. Two different amps crossing over in the 2-3kHz region may not be ideal, though.

Myself I have a single point source per channel from ~600Hz on up and a different amp here vs. below 600Hz (and yet another one from ~85Hz and down) - no issue at all. Truly, it sounds great with no perceived lack of coherence. Would a similar pair of amps from 85Hz on up do better in my system? Perhaps, or maybe not - a 600Hz XO would seem somewhat less critical using different amps. If similar amps do fare better, well, then - again - it’s just an added bonus.

My choice has been to optimize performance of the MF/HF horn with 30W Class-A (and 111dB sensitivity), and then power the heck out of it from 600Hz on down with a combined 2.5kW per channel with excellent pro amps (Lab.Gruppen and Crown). All of this is the freedom active config. affords you, not to mention setting up filter values by yourself on the fly.

My point is definitely not pro or anti either approach. My point is that in practicality there are a number of complexities and trade offs which prevent blanket statements about the superiority of either approach.

At the end of the day statements on the sonic outcome must arise from the final listening test. In all the setups I’ve heard it compared (as a separate component solution), active has always trumped passive. Let that be a blanket statement on my part for my ears, with the proviso that implementation is paramount, but even so sub-optimally implemented active still showed its merits as that which needed to be followed.