Compact Ref Crossover Help (BD-Design)

by GC, Tuesday, March 29, 2005, 23:31 (6960 days ago)

Hello All,

I've searched through the new board for ideas on constructing a passive crossover/low-pass filter for the Oris rig I'm building (FE206E loaded 200's w/ compact reference bass cabs). I've come across some suggestions such as this
[image]
and this
[image]
These do offer a great starting point, but I'm interested in learning the formula(s) used to determine the cap/resistor values.

If anyone could shed some light, or point me in the right direction, it'd me greatly appreciated.

FWIW, I'll be driving the bass cabs with a Gain clone amp that was recently a topic of discussion. My experience with GC amps has been very positive. Great sounding amps for very little cash outlay :Y:

Cheers,
Hat

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Compact Ref Crossover Help

by GC, Thursday, March 31, 2005, 23:13 (6958 days ago) @ GC

Hi Hat,

[image]

This filter is the one you'll need with changed values if needed. I would start with that filter and listen while trying to tune the bass level to your room. The bass should be in the opposite phase compared to the AER driver.

If the bass is not going deep enough (no warmth) then increase the resistor value to 1.8k or 2.2k (whatever you prefer), this will bring deeper bass. If the bass is warm enough and the bass mids are too shy then you can reduce the value for the second capacitor (more mid-bass) or increase the value (less mid-bass).

While playing with the values you'll hear what is changing, with that info you'll be able to tune the system to your room/equipment.

These do offer a great starting point, but I'm interested in learning the
formula(s) used to determine the cap/resistor values.

I mostly use the basic formula 1/(2*pi*Fc*R) but listening to what you're doing works best.

Have fun!

Bert

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Compact Ref Crossover Help

by GC, Monday, April 04, 2005, 17:31 (6954 days ago) @ GC

This filter is the one you'll need with changed values if needed. I would
start with that filter and listen while trying to tune the bass level to
your room. The bass should be in the opposite phase compared to the AER
driver.

If the bass is not going deep enough (no warmth) then increase the
resistor value to 1.8k or 2.2k (whatever you prefer), this will bring
deeper bass. If the bass is warm enough and the bass mids are too shy then
you can reduce the value for the second capacitor (more mid-bass) or
increase the value (less mid-bass).

This is exactly the information I was after. Thanks very much, Bert.

FWIW, I finally had a chance to get my system up and running this past wkend. Even with a uber-simple 1st order X-over (5.5mH inductor in series), the sound is remarkable :Y:. I have the parts en route for your suggested filter, so I'm planning on having a little fun experimenting with the values.

I'll be sure to forward photos & my impressions when I have some time.

Best,
Mike

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Compact Ref Crossover Help

by GC, Thursday, April 07, 2005, 16:56 (6951 days ago) @ GC

Sorry for my poor understanding of electronical diagramm, but I don't understand why the arrow is pointing right in the middle of the 100kohm resitor on the output side of the filter. How to make the connection so ?

Thank you in advance

J.-F.

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Compact Ref Crossover Help

by GC, Thursday, April 07, 2005, 19:54 (6951 days ago) @ GC

Hi JF,

No problem, the resistor with the arrow is in real life a variable resistor (potentiometer). The arrow is the center connection of the three normally present there. Perhaps I should have drawn the arrow althrough the resistor to make it more clear.

Ciao,

Bert

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