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Multi-Way Conventional loudspeakers with crossovers

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Old 21st October 2012, 12:06 AM   #271
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Creating a driver situation that gives a flat frequency response and a linear phase response (be it horizontal or tilted) is not the penalty, it is the prize.

Andrew
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Old 21st October 2012, 12:15 AM   #272
SY is offline SY  United States
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Quote:
Originally Posted by James Lehman View Post
CAD modeled freq response tells you nothing of the control the amp has to start and stop the cone motion.
Actually, that's exactly what it tells you- the amp can be modeled as a source impedance and variations in it examined (as Pano just showed dramatically). When you compare CAD versus measurement in the bass with real speakers and real amps, it's stunningly accurate.
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Old 21st October 2012, 01:14 AM   #273
Pano is offline Pano  United States
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Originally Posted by James Lehman View Post
CAD modeled freq response tells you nothing of the control the amp has to start and stop the cone motion.
It does tell you a lot, as SY has mentioned. It's not perfect, but pretty good.
Below is the simulated step response of the same box and driver with the same series R 0R, 0.2R and 2R. You can see that there is about 1dB more overshoot with the 2 Ohm source impedance.

I can do some actual measurements if you like, or you can do them yourself.
No argument that lower output impedance can sound different than high, but it's nice to know why.
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Old 21st October 2012, 05:19 AM   #274
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hello Wavebourn

it is quite clear that you have no idea what my point was. if you care please read it again otherwise forget about it.
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Old 21st October 2012, 05:39 AM   #275
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There are things you can do with active crossovers and multiple amps that you simply cannot do with a single amp and a passive multi-way crossover.

You have total buffering and isolation between the stages.

There is no getting around that.

If there was a total and finite winning argument for single power amp and passive crossover then active multi-amp would not be used in professional audio applications.

It is.

Regularly.

James.
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Old 21st October 2012, 06:06 AM   #276
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i can't say i did many designs with passive or active.
but there are things that come into my mind.

the series resistance of passive components is kindof the first one, allready pointed out by some.
surely inductors used in a crossover could in theory couple signals between eatch other, something no one would like. clipping of the amplifier driving the woofer will not affect the tweeter. But allso has to mention a system should never be clipping. so thisone is pointless.
CEMF is more intresting, specialy with high sensitivity drivers. here an active design does indeed have its advantage. Component value matching. hard to find trimmable capacitors that can be utilised in a passive crossover, but not hard at all for an active one.
costs are mentioned with active filters as more poweramps are needed. well.. if one takes a look at crossover part prices, it is likely that DIY poweramps may be a lot cheaper.
designing both of them is hard. But active is more felxible from a point of view.
You can't just change an inductor as easyli as get a trimm cap / resistor.
delay alligmenting speakers with passive crossover is managable, but with active allpass filter its just so mutch less of a problem.
from diy point of view the "findling" part is mutch less of a hard task with active filters.

there has gotta be verry good points besides passive filters, but i can't realy think of any.
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Old 21st October 2012, 06:30 AM   #277
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Yep. I have designed and built my share of passive crossovers. I get them. I like them for what they do.

But, I really would like to hear how they are better than active with multiple amps.

I know they work.... but make a case for how they are better.
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Old 21st October 2012, 06:51 AM   #278
MiiB is offline MiiB  Denmark
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There are things you can do with passives you simply can't do with active
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Old 21st October 2012, 07:40 AM   #279
Remlab is offline Remlab  United States
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There are things you can do with passives you simply can't do with active
Michael
You guys make some of the most beautiful looking speakers in the world. Stunning. O.K., way off topic question; What are the distortion figures like on your single ended planar magnetic tweeter? If you don't mind me asking..Or is it a true ribbon?(The apparent traces may have thrown me off)
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Last edited by Remlab; 21st October 2012 at 07:56 AM.
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Old 21st October 2012, 07:42 AM   #280
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There are things you can do with passives you simply can't do with active
Some examples please.....?
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