Active XO in plate amps

amt · 4th September 2003, 08:57 PM

Ive been wondering about this for awhile. Is it possible to use an active xo between one amp and the drivers? If one only wants to use a single stereo amp, can an electronic dividing network be used rather than a passive?

And how do the networks in sub plate amps work? If the LF info is extracted from the speaker level current and the HF info passes on to the satalites, is the HF signal now "compromised"? As in, dont use a sub plate amp w/ a high quality main amp since the sound quality leaving the main amp is not arriving at the speakers in the same condition since its been "touched" by lower quality circuitry (this is regarding your everyday plate amp and not the ones in high end subs)

amt

tiroth · 4th September 2003, 09:38 PM

Quote:

Ive been wondering about this for awhile. Is it possible to use an active xo between one amp and the drivers? If one only wants to use a single stereo amp, can an electronic dividing network be used rather than a passive?

I think the answer is no, if you are asking "can I use a single stereo amp to biamp stereo loudspeakers." You need four channels (two stereo amps) for a pair of biamped speakers.

To answer your second question, in sub plate amps the signal is often high passed, usually a 1st or 2nd order highpass. It is seldom a good idea to use this output as it seems little attention has been paid to its quality.

It would be ideal to make your own highpass to the appropriate specifications, which may be very different from those supplied by the plate amp.

amt · 5th September 2003, 12:26 AM

Let me rephase my question. Want Id like to do is replace a passive 3-way network with an active one and use only one amp. In other words, divide the signal AFTER its been amplified. I believe thats somewhat what happening with a plate amp. The entire signal is amplified, sent to the sub amp were the LF are removed but then reamplified yet the HF continue on to the satalites.
Since this is for horns, the 30watts I have is sufficient and Id rather not build 4 more channels.

So I suppose the question is can an amplified signal be divided with an active network or does it have to be line level?

amt

keyne · 5th September 2003, 09:29 AM

amt,
the signal needs to be line level and you need a separate power amp channel for each "way" of your speakers.
What the plate amp does with the speaker level inputs is voltage divide them down to line-level, filter, amplify.
This is just for convenience because many systems don't have separate Pre outs - and the subwoofer volume needs to be controlled by the master volume control. The plate amp does not take power from the main amp when connected this way.

HTH...
keyne

4th September 2003, 08:57 PM	#1
amt diyAudio Member Join Date: Feb 2003 Location: oregon	Active XO in plate amps Ive been wondering about this for awhile. Is it possible to use an active xo between one amp and the drivers? If one only wants to use a single stereo amp, can an electronic dividing network be used rather than a passive? And how do the networks in sub plate amps work? If the LF info is extracted from the speaker level current and the HF info passes on to the satalites, is the HF signal now "compromised"? As in, dont use a sub plate amp w/ a high quality main amp since the sound quality leaving the main amp is not arriving at the speakers in the same condition since its been "touched" by lower quality circuitry (this is regarding your everyday plate amp and not the ones in high end subs) amt

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5th September 2003, 12:26 AM	#3
amt diyAudio Member Join Date: Feb 2003 Location: oregon	Let me rephase my question. Want Id like to do is replace a passive 3-way network with an active one and use only one amp. In other words, divide the signal AFTER its been amplified. I believe thats somewhat what happening with a plate amp. The entire signal is amplified, sent to the sub amp were the LF are removed but then reamplified yet the HF continue on to the satalites. Since this is for horns, the 30watts I have is sufficient and Id rather not build 4 more channels. So I suppose the question is can an amplified signal be divided with an active network or does it have to be line level? amt

5th September 2003, 09:29 AM	#4
keyne diyAudio Member Join Date: Jul 2003 Location: earth	amt, the signal needs to be line level and you need a separate power amp channel for each "way" of your speakers. What the plate amp does with the speaker level inputs is voltage divide them down to line-level, filter, amplify. This is just for convenience because many systems don't have separate Pre outs - and the subwoofer volume needs to be controlled by the master volume control. The plate amp does not take power from the main amp when connected this way. HTH... keyne