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Multi-Way Conventional loudspeakers with crossovers

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Old 28th December 2012, 10:10 AM   #131
ODougbo is offline ODougbo  United States
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Always looking for good drivers that don't cost $100 each.

Peerless/Vifa/Morel have been good so far. I had a pair of Seas Prestige that were trouble (could have been something else I guess).

SOOO many driver to chose from, hard to pick one!
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Old 28th December 2012, 07:40 PM   #132
balerit is offline balerit  South Africa
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In my opinion all drivers are the same, I currently use el cheapos in my Camm DynaTones and they work well, it's how you test and use them that counts.

Voigt Pipe, DIY Tapered Quarter Wave Pipe (TQWP) loudspeaker plans - The Book Worm
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Old 29th December 2012, 07:58 AM   #133
ODougbo is offline ODougbo  United States
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Well I guess they are all the same in a global sense.

So your speakers remind me of some subwoofers - check posts 301 - 310:

Isobaric - less then $20
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Old 29th December 2012, 08:34 AM   #134
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Quote:
Originally Posted by balerit View Post
The morel of the story is never mix speakers with different impedances and keep the woofer and tweeter sensitivities the same.
I'm sorry, but this is not a good rule of thumb. Mixing different voltage sensitivity and impedance is fine.
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Old 29th December 2012, 09:26 AM   #135
ODougbo is offline ODougbo  United States
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Thanks Wolf,

I see that a 8ohm tweeter would need a smaller cap (1/2 the size of 4ohm)

2-Way Crossover Designer / Calculator

Is that all I need to change in the xo designed for the 4ohm tweeter?
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Old 29th December 2012, 10:14 AM   #136
balerit is offline balerit  South Africa
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Quote:
Originally Posted by wolf_teeth View Post
I'm sorry, but this is not a good rule of thumb. Mixing different voltage sensitivity and impedance is fine.
Later,
Wolf
Well then you are discounting 50 years of research by the top people in their field and it's statements like this that make a mockery of High Fidelity.
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Old 29th December 2012, 03:00 PM   #137
system7 is offline system7  United Kingdom
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A mockery indeed. Or not. Let's get back to ODougbo's speaker.

It does seem to me this is a very high inductance woofer. 0.8mH is a LOT for a 4 ohm unit. Usually you'd be around 0.4mH here.

It's gonna fight anything you do to roll it off with a small bafflestep coil.

That means you get a midrange peak when you add shunt capacitance unless you filter it very low. So you need some shunt resistance too.

My experience with high-inductance woofers is they filter best with a simple coil or a coil plus a Zobel, which here at 3.7R and 0.8mH is 4.7R and 35uF.

You then get left with a natural rolloff around 4kHz and a need to bring the treble in quite high at 4kHz.

Something to ponder. system7!! Steve!!
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Well, there it is! Best regards from Steve in Portsmouth, UK.

Last edited by system7; 29th December 2012 at 03:02 PM. Reason: Corrected Link to Morel Woofer.
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Old 29th December 2012, 09:44 PM   #138
ODougbo is offline ODougbo  United States
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Steve,

Ahhh the plot thickens...I'm sure the woofer/tweeter xo is below 2K (but will check) The XT25TG30-04 says it goes to down to 1,500.

btw, back in the day when we made a bunch of these, we used a simple 6 db slope with a .7 coil (for the woofer).

Zobel network - is diagram correct?

I have the parts, large caps & resistors.

Thank you again
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Old 29th December 2012, 09:56 PM   #139
system7 is offline system7  United Kingdom
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Yup, the bass filter is right. Whether that sounds right is a matter for trial and error. The treble filter would need adjusting either for low slope or a high crossover frequency. It seems the polycone bass will have a natural rolloff around 4kHz.

The reason I complicated the issue is you were following my suggestion of reducing the crossover shunt resistor. Well, that might not work with a high inductance woofer at 3-4kHz, which yours is.

I think I would have to do some modelling with a suitable 4 ohm 0.8mH driver to see how it all works. My comments may not have been entirely helpful until that is done.

Usual random pictures...
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File Type: jpg Epos ELS-3 Crossover.JPG (15.8 KB, 11 views)
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Old 30th December 2012, 09:09 AM   #140
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Originally Posted by balerit View Post
Well then you are discounting 50 years of research by the top people in their field and it's statements like this that make a mockery of High Fidelity.
Look around, mixing these considerations is done all the time, it's not just me.
I wouldn't for tube-amps, but that's a different story.
Later,
Wolf
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