[davidandleigh]

I am assembling a 3-way active speaker with fairly standard ~300Hz/~3000Hz crossover points.  I'm trying to decide if all 3 drivers should be powered by the same amplifier (i.e. 3 identical stereo amplifiers for the pair of speakers), or if the amplifier power should be tailored to each driver.  I could do 200W for each driver, which seems excessive for the tweeter, or 70W/130W/200W across the drivers.  Any suggestions or experiences would be greatly appreciated.

Thanks,
Dave

[JLM]

Overkill - agreed, but one 6 channel amp is cheaper than 3 different amps (or 6 monoblocks).

Ideal would be to use different sizes from the same vendor/family of amps.

Some like tubes for midrange/tweeters (better imaging, sparkle) and solid state for woofers (better damping).  In that case, again going with the same vendor might be advantageous.

[davidandleigh]

Thanks for the feedback.  I hadn't even considered using tubes for the HF and SS for the LF.  I'm going to start researching this approach.

[Æ]

I also like the idea of using tubes for tweeters and transistors for woofers! Horsepower for the bass and some sweetness for the treble.
Just out of curiosity, who said 300Hz and 3,000Hz are "standard?" I hope you picked/designed the crossover based on driver performance and not on arbitrary numbers.

[davidandleigh]

Absolutely.  They're not even working out to 300Hz/3000Hz.  I was more concerned about conveying the basic implementation.  I probably should have stated that the 3-way has a 1" tweeter, a 6" mid, and a 10" woofer.  Thanks.

[JohnR]

Sounds interesting. Will you be building the amps yourself?

[davidandleigh]

I wasn't originally planning on it.  I've been building speakers for a number of years and was looking to step up the quality/risk/reward/challenge threshold a bit.  This project is going to use some higher-end drivers that will likely require some extensive enclosure design (stiffness and damping).  You've got me interested in the DIY amplifiers.  I'm looking at a pretty large amplifier expensive with all the needed channels for the active crossovers.  Are self assembled amplifiers a good performance / price option?  Suggestions on resources?  Thanks.

[JohnR]

I wasn't originally planning on it.  I've been building speakers for a number of years and was looking to step up the quality/risk/reward/challenge threshold a bit.  This project is going to use some higher-end drivers that will likely require some extensive enclosure design (stiffness and damping).  You've got me interested in the DIY amplifiers.  I'm looking at a pretty large amplifier expensive with all the needed channels for the active crossovers.  Are self assembled amplifiers a good performance / price option?  Suggestions on resources?  Thanks.

I'd look into a solution using off-the-shelf class D amp boards. You can always chuck them away later if you find something genuinely better. Look up (google) hifimediy, connexelectronic, sure electronic. Not that there's anything wrong with buying a rack of off-the-shelf amps either.

[Redefy Audio]

how about class d audio?

they got 60w 8ohm up to 250w 8ohm, prob cannot use the same PSU, but its the same family.

cheers
henry

[JoshK]

My $.02.

How do you want to do the xo?  miniDSP?  Those seem cheap, good and easily configurably to take into account real speaker design needs like notch filters, shelving, BSC, etc, in addition to standard slopes.

To get going quick, I highly recommend picking up a used 6ch amp off a'gon cheap and get moving.  Worry about upgrading it with different/custom/diy'd made amps later and then reflip the used amp on a'gon again.  If you are smart, this will cost you little extra. 

I've been in the situation where I never completed said project because I was always needing to finish one piece.  Do chew on too many parts at once. 

You need surprisingly little watts for tweeters and even mids.  The bass is where you need the most, but unless your driver is terribly inefficient, or the tuning poorly chosen, you won't need more than 100w either as the passive loss producing components such as inductors aren't there with the active design.

[Æ]

You need surprisingly little watts for tweeters and even mids.  The bass is where you need the most, but unless your driver is terribly inefficient, or the tuning poorly chosen, you won't need more than 100w either as the passive loss producing components such as inductors aren't there with the active design.

Decent inductors have very little insertion loss (low resistance).

[mboxler]

Hi Dave...

I found Rod Elliott's articles http://sound.westhost.com/bi-amp.htm very helpful, if you haven't read them already. 

Good luck,

Mike

[davidandleigh]

JoshK, you bring up some good points and I already have enough amplification channels to power the system.  Wouldn't be perfect but isn't a necessary design effort while I'm designed the speaker and XO.  I initially was looking at the miniDSP, but really haven't read many positive reviews.  Noise issues!  The active XO implementation is probably the least mature aspect of my project.

mboxler, thanks for the link.

[jerryleefish]

I use a 3 way system crossing over at 250 and 3500 hz. I bi amped having the midrange and tweeter on one amp and the wolfer on the other. I use a passive crossover with the wolfer and coil circuit separated from the other components.
Using this method you may find an imbalance between the wolfer and other components. An efficient bottom end will over power the treble speakers. Attenuating the bass amp would be required in this case. My amps are 40W PP
tube.