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Multi-Way Conventional loudspeakers with crossovers

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Old 18th October 2012, 08:31 PM   #131
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Originally Posted by cotdt View Post
I agree that active is theoretically superior just because there are less components in the signal path, however the arguments in favor of active such as damping factor, efficiency and temperature stability is rubbish. People keep parroting these things. Look at the math, do some measurements. The minor differences with passive are not going to matter.
The founder of ATC Billy Woodman claims an insertion loss for passive xovers of up to 9dB depending on complexity and I measured 3dB on my Tannoy woofer which used a simple 2nd order lo pass consisting of a series inductor and a parallel cap with inline with a 2R2 resistor.
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Old 18th October 2012, 08:41 PM   #132
tinitus is offline tinitus  Europe
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well, a large valued inductor can take quite some power out of a woofer
some big inductors are better in that respect
but could easily cost as much as the woofer itself
so I guess not many will have had that experience
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Old 18th October 2012, 08:44 PM   #133
4Torr is offline 4Torr  United States
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Originally Posted by Charles Darwin View Post
The founder of ATC Billy Woodman claims an insertion loss for passive xovers of up to 9dB depending on complexity and I measured 3dB on my Tannoy woofer which used a simple 2nd order lo pass consisting of a series inductor and a parallel cap with inline with a 2R2 resistor.
9 db ? Are you sure? The crossover is absorbing 79% of the input power?
I read somewhere that reactive crossover elements should be 1/10 or less the driver's dcr inline with the driver to be a good design. That's about -1 db insertion loss.
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Old 18th October 2012, 08:46 PM   #134
gedlee is offline gedlee  United States
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Originally Posted by 5th element View Post
Is (active) always going to sound better? This much is less clear because even the objective side of things can recognise when a passive crossover is perfectly adequate to the cause and that going active isn't going to bring about any real worthwhile gains. Is going active in this case ever going to sound worse, no, it shouldn't, unless you've done something wrong.
I completly agree, but I will point out one thing that I have found. For a woofer it is difficult to have a peak in an passive crossover. That's because to get a peak you have to attenuate everywhere else. Because active has gain, a peak is no more difficult than a dip. Since a compression driver is virtually always attenuated to match the woofer, peaks are not a real problem, but for the woofer they are. So active does have that one significant advantage to it.

To the guy who wants to ignore cost because its DIY, I don;t think that is reasonable. Cost is always a factor, just not so much with DIY. And there are a lot of discussions here that are not exclusively DIY. WHen I first stated looking at active DSP crossovers they were in the thousands per unit. That is not a cost that anyone can ignore. Today it is quite different and I use both active and passive.
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Old 18th October 2012, 08:47 PM   #135
cotdt is offline cotdt  United States
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-9 db!? I'm not sure what's going on there, but I usually get -1dB or less on the woofer in my crossovers. Maybe he is including baffle step compensation into the losses?
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Old 18th October 2012, 09:11 PM   #136
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All very reasonable, I'm sure, but there is a meme going about that while active are OK for beginners and philistines, an active is no match for a well-designed passive crossover. The argument may be along the lines that passive crossover design is "hard" and the designer has to serve such a long apprenticeship that he inevitably does it better than the idiot with the computer. But... we also hear the claim that passive crossover design is all about science and measurements and objectivity. Well a computer can calculate in a second what even a member of The Crossover Designer's Guild would take a lifetime to do. There is no magic we're told, so the calculations and formulae are already defined. So let's stick them in a computer and come up with the truly optimum passive crossover and marvel at its beauty. But passive electronics is all about conflicting requirements and compromises (an 8th order passive is practically impossible, we're told, for example), so the digital active has simply got to be better in strictly objective terms.

Personally I'm not interested in the slightest in any non-DIY considerations like hardware cost and size, so I don't think they have any place in this discussion; I want to build the best possible system and I haven't yet heard a real, non-magical, argument in favour of passive crossovers.

(Listening to my homebrew digital active system at the moment, and it's fantastic, and I haven't even done any correction based on measurements yet - very little needs doing. I might not have fared so well if I had put the drivers and box together myself, however...).
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Old 18th October 2012, 09:17 PM   #137
Jay is offline Jay  Indonesia
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Originally Posted by 5th element View Post
It is extremely easy to understand why people can have bad experiences with active xovers and for who the best sound they have ever heard, has been from a passive system.
I think it depends on the level of the audiophileness

At low level, it is hard to find anyone that will not prefer or be impressed by active. That's why threads such as this will always appear.

At very high level, active analog is not there yet. So how about active digital? Remember, many high level audiophiles at this moment do not even consider digital for music source. This is because digital technology has not been perfect or cheap. Same as digital crossover technology.
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Old 18th October 2012, 09:21 PM   #138
puppet is offline puppet  United States
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Every industry goes through this stuff CopperTop. Hand tools get replaced with power tools. Some skills get lost, others bloom out of the ashes. Folks fight to hold on to the familiar. ... just the way it is.
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Old 18th October 2012, 09:22 PM   #139
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Originally Posted by gedlee View Post
To the guy who wants to ignore cost because its DIY, I don;t think that is reasonable. Cost is always a factor, just not so much with DIY. And there are a lot of discussions here that are not exclusively DIY. WHen I first stated looking at active DSP crossovers they were in the thousands per unit. That is not a cost that anyone can ignore. Today it is quite different and I use both active and passive.
That might be me. Again, very reasonable, except the passive crossover designers want us to believe that it's so incredibly difficult, what with their having to juggle hundreds of variables written down on vellum (or whatever sounds best...), that the process of condensing all this down into three components takes hundreds of hours. If you value your time, then the cost of a PC, sound card and a couple of secondhand amps is nothing. I may be after the best, but I still hate spending money; my system has cost about 150 all in, but I don't think that it would sound any better if I spent many times that amount on the hardware.
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Old 18th October 2012, 09:30 PM   #140
Jay is offline Jay  Indonesia
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Originally Posted by CopperTop View Post
All very reasonable, I'm sure, but there is a meme going about that while active are OK for beginners and philistines, an active is no match for a well-designed passive crossover. The argument may be along the lines that passive crossover design is "hard" and the designer has to serve such a long apprenticeship that he inevitably does it better than the idiot with the computer.
No, it is not about that. Observe this: there is nothing you can do with passive crossover against cheap drivers (It is better to run them full range without crossover at all).

With passive and complex crossover, a good quality amp must be assumed, don't you think so?

Quote:
Originally Posted by CopperTop View Post
I want to build the best possible system and I haven't yet heard a real, non-magical, argument in favour of passive crossovers.
It is there. Between the lines. Can a computer read between the lines?

Quote:
Originally Posted by CopperTop View Post
(Listening to my homebrew digital active system at the moment, and it's fantastic, and I haven't even done any correction based on measurements yet - very little needs doing. I might not have fared so well if I had put the drivers and box together myself, however...).
Cool. The audio hobby is crazy. Just mention your speakers, amplifiers, source code etc, and we will see. Can you? Computers are not smarter than human.
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