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(big snip)........ they do not magically solve the problems of designing a quality loudspeaker using real-world drivers.
Also, note that effective implementation of an active crossover, analog or digital, is not trivial. Active crossovers are a tool, and the results will be no better than the capabilities of the man using the tool. They are not a panacea - while active (especially DSP) crossovers can often address issues that are not readily addressed with a passive circuit, they do not magically solve the problems of designing a quality loudspeaker using real-world drivers. Duke
While the finest system I heard at RMAF 2007 and CES 2008 (the Sonicweld Pulserod) used a hotrodded DSP crossover, achieving that system's level of transparency is not trivial and so I am not sure that it would be cost-effective in most situations.
I guess that is my real issue with all of this. The drivers you speaker designers have to choose from can be less than design friendly (in my opinion). Then again I were King of the Speaker World, ALL speakers produced could be easily driven to ear splitting levels with 2.5 watts on a zero feedback amplifier, produce deep bass in a 2cuft cabinet, have an even impedance curve without weird phase anomalies, rolled off at a nice smooth -6db per octave and showed no signs of cone breakup and was uber linear with little or no nasty distortion characteristics. Better yet if this driver from dreamland not only did bass but extended at least up to 14k. Thats not asking too much....is it? Unfortunately this isn't the case. You guys are forced to drive finish nails with sledgehammers at times.....and believe me, I DO understand exactly what you are talking about when it comes to XO design, I didn't just fall off the turnip truck. I guess my issue is more with the industry that continues to make mediocre drivers (that should precipitate some nifty responses) and forces your (collective) hands into to using more and more complex filters in speaker designs. Thats not to say you guys don't push these speakers and designs to get the last ounce of music out of them but you have to admit that if you could get by with fewer crossover parts and shallower slopes you'd jump at the chance....wouldn't you?
As I said before, get rid of your passive crossovers and free your speakers. Until you hear what the advantages are, you will never know what you are missing. As for burden of proof, Ryan lets get together sometime later this summer and play with a few different ideas. Maybe pick a driver or two that you've got in stock that rolls off smoothly (ie no heavy cone breakup) where we can bi/tri amp the conceptual design using an active XO. If you want, we can use my Focal's, they roll off reasonably smooth. We can knock together some cabinets up in the wood shop. You can put together a quick passive XO and we can listen to them both ways. Then we can let our ears decide which is better. I think you will be surprised.As I said in my first post, everything in audio is a compromise. On the speaker design side, more complex XO's are just that, a compromise you use to control drivers and their responses. You play the cards you are dealt. It just doesn't fit into my Utopian view of what audio should be. Then again, I seem to 'buck' the norm more often than not.
big snip....... I haven't tried to do something with flat as possible woofers and tweeters lately, but I have a couple perfect projects in mind, and the drivers here. It might be a fun experiment to try and report back here. I'm betting on my crossover though
Quote from: TurboFC3S on 7 Jul 2008, 09:58 pmbig snip....... I haven't tried to do something with flat as possible woofers and tweeters lately, but I have a couple perfect projects in mind, and the drivers here. It might be a fun experiment to try and report back here. I'm betting on my crossover though Cool. Lets plan on it later this summer. You might be right about your XO but keep an open mind. I think you'll have a very pleasant surprise when you hear how a good active sounds. Maybe by then I'll have my AR EC-3 tubed XO back. That thing is extremely cool but not very flexible. It has a fixed 12db slope though there are plenty of XO points.
TurboFC3S, Do you feel there is any sonic penalty to be paid when you have use response shaping elements and notch filters in a design in order to hit the desired response characteristics compared to a simpler xo design with lower parts count. Scotty
Quote from: Duke on 30 Jun 2008, 07:21 amWhile the finest system I heard at RMAF 2007 and CES 2008 (the Sonicweld Pulserod) used a hotrodded DSP crossover, achieving that system's level of transparency is not trivial and so I am not sure that it would be cost-effective in most situations.If one only knew the dedication to his craft, time spent perfecting said craft, and in-depth digital and DSP design knowledge that Josh Heiner (Sonicweld) has, they would quickly realize that utilizing an active crossover with DSP it is not a trivial undertaking or cost-effective solution whatsoever. However, to my ears, his speakers produce the finest reproduction of recorded music I've ever heard.He is slammed building product, doing high end medical and military design projects, so I doubt seriously he would ever find the time to post here, but visit our room at RMAF and feel free to ask him how much work and how many years he has invested to be at the point he is, you'll get an earful! Disclaimer--Josh is my closest friend and I have watched his growth as a designer over the last 15+ years, so call me biased if you'd like. Peace, Lee
As Roger suggested, the really interesting "tweener" (but largely ignored) is the passive line level, maybe with buffers. There have been some versions over the years, but usually implemented with lousy sounding op amps and cheezy power supplies.
True you don't need a Zobel with active xovers, ...
The main advantage I see to an active network and multiple amps is being able to eliminate back-emf, but that's not exactly a major concern.
