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Multi-Way Conventional loudspeakers with crossovers

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Old 30th April 2013, 10:56 PM   #21
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Default didn't get it right

system7: and of course as soon as I said that:
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Old 30th April 2013, 11:06 PM   #22
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Default didn't get it right

sorry cleared up:
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Old 1st May 2013, 06:39 AM   #23
system7 is offline system7  United Kingdom
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Ah, NOW we're cooking with gas, Danny!

That's your typical 6" driver with a peak around 4.5 to 5kHz! We can do this. It's a bit like the Reed cone SEAS ER18RNX.

Simple bafflestep and a notch in Dynaudio style. I've pretty much nicked Troels' XT25 circuit:
Peerless HDS PPB 830860

That 3.3R input resistor is your tweeter level adjust, and it can be anything you like and impedance stays good. I'd start with closed box and fit a reflex tube later if you want. But it all works rather well. I have, of course, made some allowance for the flattish FR and lower efficiency of the XT19 in the Boxsim modelling. It has to be third order tweeter because of the non-ferrofluid nature of the XT19.

It's a 3kHz crossover and coil resistance is not critical, but you'd use aircoil on the tweeter and notch for sure. Ferrite core or good aircore on bafflestep. 250V polypropylene caps and 5-10W wirewound resistors.
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Good Night, and Good Luck. Best regards from Steve in Portsmouth, UK.

Last edited by system7; 1st May 2013 at 06:50 AM. Reason: More construction detail added.
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Old 1st May 2013, 07:04 AM   #24
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Quote:
Originally Posted by system7 View Post
I'd start with closed box and fit a reflex tube later if you want. But it all works rather well.
I'd start with an open back kind of box. And rather stuffed ( acrylic or cotton or wool ) ....
It should have also some kind of 'sculptured baffle', or also trapezoidal ( but 90 rotated )

Last edited by picowallspeaker; 1st May 2013 at 07:08 AM.
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Old 1st May 2013, 02:40 PM   #25
balerit is offline balerit  South Africa
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Quote:
Originally Posted by badman View Post
Appears to have been trolling- post nonsense then disappear quickly
I don't usually respond to such childish behaviour, once again show me a source which says you can. @Sean the reason is that the sensitivities won't be the same and the overall impedance of the crossover could be too low and may blow your output trannies.
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Old 1st May 2013, 02:55 PM   #26
pkitt is offline pkitt  United States
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Default You can't be serious???!!!

A tweeter is almost always more sensitive than any other drivers in the system and has to be attenuated to match them, and even more so in order to have the proper BSC. So, if you have a 4-ohm tweeter matched up with an 8-ohm midwoofer in a 2-way for instance, you could very well end up with a 4-ohm resistor in series with the tweeter and "voila", you now have a nominally 8-ohm load on the tweeter's crossover. But even if the impedances don't end up as perfect matches, it doesn't matter one iota because you will have designed the crossover properly. Oh, maybe YOU won't have done that but EVERYONE else will have. Also, very few speaker systems have an overall impedance so low as to blow an amplifier. If that does happen, either the amplifier's design is suspect or the speaker design was deficient. I can't believe you're so naive or so lacking in knowledge. Shaun, I hope you're completely ignoring everything balerit has said.
Paul

Quote:
Originally Posted by balerit View Post
I don't usually respond to such childish behaviour, once again show me a source which says you can. @Sean the reason is that the sensitivities won't be the same and the overall impedance of the crossover could be too low and may blow your output trannies.
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Old 1st May 2013, 05:16 PM   #27
FE3T is offline FE3T  Norway
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Originally Posted by balerit View Post
I have been designing crossovers and writing books on the subject for 20 years, show me one source that says you can.
JBL XPL200A
These use a 4 ohm middome, the rest of the drivers are 8 ohm

Look at the .pdf and check out the replacement cones and diaphragms + complete Xover wiring diagram

Tweeter D8R046Ti
Midrange D4R093Ti
Low/mid C8R115H-1
Woofer C8R2214

Bold number=Z

8ohm tweeters are also VERY commonly used with 4ohm woofers in automotive component kits
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Old 1st May 2013, 05:57 PM   #28
system7 is offline system7  United Kingdom
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I really do wonder why we are having a flame war about matching impedances of drivers. Really transistor amps couldn't give a hoot. But I always go for the easy high impedance as it goes.

Let's talk sloped baffles and time alignment. Here's what it looks like:

Click the image to open in full size.

Click the image to open in full size.

And below a suitable crossover I hope. Based on some guesswork born of experience, but should be sweet. Frankly, I'm a bit like Beethoven, I just need to read the score to hear the whole thing in my head. You can't teach that in school.
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Old 1st May 2013, 09:06 PM   #29
sreten is online now sreten  United Kingdom
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Quote:
Originally Posted by balerit View Post
I don't usually respond to such childish behaviour, once again show me
a source which says you can. @Sean the reason is that the sensitivities
won't be the same and the overall impedance of the crossover could be
too low and may blow your output trannies.
Hi,

You don't know the subject your pontificating about.

A 4 ohm tweeter of the same sensitivity as an 8 ohm bassmid
can easily be used with it, for reasons you can't work out.

rgds, sreten.
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Last edited by sreten; 1st May 2013 at 09:11 PM.
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Old 1st May 2013, 09:09 PM   #30
FE3T is offline FE3T  Norway
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Guess i wasent all that far off the green after all then, the above mentioned XPL200A`s sports stepped baffles, placing the tweets and mids about 1" behind the low mid and the woofer.

Quote:
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Let's talk sloped baffles and time alignment. Here's what it looks like:

Last edited by FE3T; 1st May 2013 at 09:12 PM.
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