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View Full Version : Using a 4 ch amp to go active.



JDBoogie
06-03-2008, 05:20 PM
I was reading an article about a guys setup that was using a 4 ch amp to run his front stage over a active crossover.:wow:

Anyone know exactly how this is done? Does he bypass (not use) the passive x-overs and just run one ch to each speaker?
Example:
channels 1and 3 to tweets
channels 2 and 4 to mids?

do u run the mids bandpass or maybe at 80hz?

Im really interested in trying this with my Dyn 242's and a JL 300/4. The Dyn's are pwr hungry and I hear that going active will really get the most out of them. :cool:

dumple
06-03-2008, 05:25 PM
id think 1 and 2 for woofers 3 and 4 for tweets then using the onboard crossovers and filters of the amp to adjust to the frequency range you want for both like 37-2500 or somethin for the woofers then 2500-xxxx for the tweeters. Im not 100% on that but i think

Alpineforever
06-03-2008, 09:26 PM
What channels you use depends on your amp, like for my SAX 100.4 I have 4 channels and 1 and 2 work off the same crossover and 3 and 4 work off the same crossover, so I have my tweeters on channel 1 and 2 and my mids on channel 3 and 4.

You will want to bandpass the mids rom around 80 Hz up to around 2500 Hz, and the tweeters simply get a HPF which is usually safe if you start at about 3000 Hz and then work your way down slowly.

You do no use the passive crossovers at all.

Most amplifiers cannot properly do an active crossover without help because they lack the ability to bandpass, so you will either need an active capable head unit or an external processor that can give u an LPF or an HPF to be used in concert with your amplifiers HPF or LPF to create a bandpass.

In my setup I have a head unit that isn't active capable so I have RCA's going to mchannel 1 and 2 like normal and then channel 1 and 2 are for the tweets and i use my amps built in HPF to cross them over at about 2600Hz and the speaker wire goes directly from the channel outputs on my amp to my tweeters.

In order to create a proper bandpass however i bought an adjustable crossover which is placed in between the head unit and the amplifier. RCA's go form my head unit to my crossover and then i used the crossovers HPF to begin my woofers crossover at 80Hz @18db/octave, and then I have RCA's coming from the output on my crossover to my amplifiers channels 3 and 4. On the amp I used the LPF at 2500Hz, thism ixed with the HPf on the adjustable crossover creates a proper bandpass, and from their I have speaker wire going to my woofers out of channel 3 and 4.