BX63A Definitive Answers Needed

[parisphoto]

Hi,
I've done my research, but I'm still confused.
1- What is the correct way to connect a BX63A to a pair of B380 subs ? I'm using the 2nd set of outputs on my preamp.
2- Should adjusting the Low Pass point on the BX63A in any way affect the output of my full range speakers?
3- Would anyone have an owner's manual, (not the 2 page Tech Manual), that they would sell me a copy / pdf of ?
Thanks to all.

[Robh3606]

Hello parisphotoI use a single BX-63A to drive both of my B380 clones. I have a Y spliter on the output of the BX-63A and it drives a pair of strapped Crown 150A Series 2 amps. The Crowns are strapped by using a switch on the amplifier. They are both driven from the "Normal" non inverted output of the BX-63A. You use the Impedance switch on the back to match with the amplifier driving the main speakers. Here is part of the manual hope it helps. Rob

[parisphoto]

Thanks Rob,

PM sent.

[rusty jefferson]

Robh, Perhaps you could scan that complete owners manual?

The pages you showed describe the way the crossover is designed to be used, in line between the preamp and both the full range and sub amps. I know some people use them the way Parisphoto described he currently has his configured, using one set of preamp outputs directly to the full range speaker amp, and the second set of preamp outputs to the BX63A to feed the sub amp. I imagine, in certain systems one method or the other may sound best.

Can you tell me from the schematic what the slope is, and at what frequency the (low pass) passive filter starts to roll off the full range signal when you engage the network? I am assuming (and understand the danger there) there is a roll off of low frequencies at a particular (fixed) point/slope when you engage the network.

[Robh3606]

Hello Rusty

I know some people use them the way Parisphoto described he currently has his configured, using one set of preamp outputs directly to the full range speaker amp, and the second set of preamp outputs to the BX63A to feed the sub amp.

That's how I use mine. I will scan it when I get a chance. I just measured a BX-63A and posted the measurements. I will just repost them here as well.

Attached are two plots that have the low frequency output measured at 63Hz, 90Hz and 125Hz and a second which has the high pass with the 125Hz curve.

Rob

[rusty jefferson]

Thanks Robh,

I didn't see your earlier post of this graph. That's what I was looking for. So.....is that a 6db slope engaging at about 200hz, on the high pass? Am I reading that correctly?

[Robh3606]

Here's the complete manual. Yes that 200Hz looks about right.

Rob

[grumpy]

Hmm.. from the plot, I would read the passive high-pass as being down 3dB at ~50Hz...
and dependent on the amplifier input impedance as well as the choice of resistors switched
in with the "Impedance Accommodation" switch position. The slope is so shallow and most
amplifiers likely fall within the "Mid" setting's impedance range, that this isn't insanely
critical, but the high-pass frequency is not just one set value for all systems.

There are some explicit assumptions in using this device (as intended) beyond the choice
of subwoofer and it's characteristics (port tuning, etc... the B380 and B460 being obvious
choices). One being that the main L-R speakers response rolls off somewhere lower than 60Hz
(the passive hi-pass function essentially making the natural system roll off that much steeper).
With the -A model, one has the option of 'filling in' a higher range with the subwoofer, but
I don't see this (personally) as optimal.

IF the Impedance Accommodation switch has been properly set, then for the main speakers,
you are done. After that, it's matching the subwoofer level to that of the mains, and then
adjusting the active low-pass crossover frequency to match the combination of the mains
now-modified roll off frequency (such that a large bump or null is avoided where the two
speaker ranges combine).

Hope this helps and isn't too obvious. The manual should be a big help (Thanks Rob).

[Titanium Dome]

Finally, a post of the "missing manual."

Thanks.

[parisphoto]

Rob,
Thanks so much for posting the manual.

[Robh3606]

Your welcome. I never realized that we didn't have one somewhere on the site.

Rob

[hjames]

Your welcome. I never realized that we didn't have one somewhere on the site.

Rob

Excellent, Robh!
"The Missing Manual"!
Thanks so much for this ...