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tweeter compensation in active set-up [message #35088]

Tue, 12 February 2002 05:01

replay
Messages: 284
Registered: May 2009

Grand Master

hi gang, now that i'm running an active x-over with my 4 pi's shouldn't i change the tweeters compensation network? there is no need to attenuate the tweeter because the x-over takes care of that, right? do i not simply need to simply boost the top octave response? which circuit do i use? am i not wasting power from my quad II's with this original network? wayne, if you can tell me what components i need to extend the top octave maybe Till E can do a sand illustration for me and i'll be all set.

thanks guys,

cheers,

george

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does your active xover have HF eq built in? [message #35089 is a reply to message #35088]

Tue, 12 February 2002 05:48

Sam P.
Messages: 307
Registered: May 2009

Grand Master

If not, maybe leave the resistor network and bypass cap alone, to preserve the proper response Wayne designed for. Just remove the 1.6 kHz. xover board from the path, if you have not done so already. Set your level controls for the LF and HF outputs to unity, the speakers comp net will handle the level diff. for you.. If your amps are different, some level tweaking will still need to be done...make YOUR ears happy.

tweeter amp + will need to connect to where you soldered R1 and R2 to each other. the xover board HF + out is/was wired there.

tweeter amp - out will connect to the other end of R2, which is also connected to the - terminal of the HF driver. the xover board LF - out is/was wired there.

bass amp + out will wire directly to the + terminal of the woofer.

bass amp - out will wire directly to the - terminal of the woofer.

It would be simplest to remove the HF wires where they exit the xover board, then extend them back to the amp...that way you don't have to mess with R1/R2 solder joint, etc. at all. Same goes for the LF wires, remove the wires at the old xover board, and extend them back to the amp. Easy to fix back into the original config. later if needed. Good luck, Sam

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Re: does your active xover have HF eq built in? [message #35090 is a reply to message #35089]

Tue, 12 February 2002 05:57

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Messages: 284
Registered: May 2009

Grand Master

hi sam, the original eminence x-over was already removed. everything sounds fine and the output levels have been optimized on my rane x-over. my question is: am i not still attenuating the tweeter to match the woofers output with this original tweeter circuit and thus wasting valuable power?

thanks,
george

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Re: does your active xover have HF eq built in? [message #35091 is a reply to message #35090]

Tue, 12 February 2002 06:39

Wayne Parham
Messages: 18693
Registered: January 2001

Illuminati (33rd Degree)

When running an active crossover, remove the passive crossover, including the tweeter compensation circuit. At the preamp/crossover, provide tweeter EQ with the following curve:

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Re: does your active xover have HF eq built in? [message #35092 is a reply to message #35091]

Tue, 12 February 2002 06:52

Adam
Messages: 419
Registered: May 2009

Illuminati (1st Degree)

Wayne, what type of horn are the CH-3's? Constant directivity? The response graph in your papers doesn't show any HF rolloff other then the natural 3db of the driver. No worries, just curious.

Adam

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are you driving the HF with the quad II's? [message #35093 is a reply to message #35090]

Tue, 12 February 2002 07:14

Sam P.
Messages: 307
Registered: May 2009

Grand Master

Then don't sweat the lost power, if the end result is a more linear freq. response. Sure, you don't have the intimate amp to voice coil interface like the bass driver, but hey, the HF is damped by the network, yes?

Later, you might wish to try learning about the opamps/active filters more, with an eye towards being able to tailor a gain stage to have the desired EQ characteristics the HF needs for being flat. Can also add a stage with low end eq for the bass.

For example, in my preamp, there is a "+6 dB at 50 Hz." contour circuit...all it is, is a cap and resistor in front of a gain stage. There is even a bread board type kit out now, to learn and play with these things. And web resources. Depends on how far down the road in this hobby you wish to travel.

Sounds like you already have your system pretty well sorted out for now. Sam

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Re: does your active xover have HF eq built in? [message #35094 is a reply to message #35090]

Tue, 12 February 2002 07:42

ToFo
Messages: 219
Registered: May 2009

Master

Replay,
which rane x-over? My AC-23 has holes in the board for a cap correcting CD horn response. If you use a smaller cap you could compensate for a higher freq. The Rane manual covers this topic, but doesn't list frequencies higher than 6K. If you do not have a manual, Rane has all of this online.

Thomas (the latest Pi newby)

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Re: does your active xover have HF eq built in? [message #35095 is a reply to message #35091]

Tue, 12 February 2002 07:47

replay
Messages: 284
Registered: May 2009

Grand Master

hi wayne! my x-over is a rane ac22 2 way x-over with 24db/octave filters. there is no hi-freq eq, just low & high gain controls. should i purchase an eq to run between the x-over and amp thus enabling to correct the response curve of the psd2002? really the sound now is fine with your tweeter network installed, i'm just want to get the best sound possible.

cheers,

george

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