Active crossover on the cheap???

Early B.

Question --

Is it possible to pursue an active crossover without incurring the expense of new speakers? In other words, can you rip the guts out of an existing pair of speakers, add extra sets of binding posts, if needed, grab an external crossover and some amps, and be done with it?

zingo

I guess I don't see why not... If you were building a pair, you would just not include the crossovers, so I would think the opposite would be true.

strider

Why not? Especially if you're using drivers you're familiar with already, rather then disassembling a speaker and guessing about it's driver's parameters.

Do you already have a crossover?

I've been looking into building an active crossover; if you'd like links to some things I"ve found so far, just let me know.

Ben

Early B.

strider wrote: »

Do you already have a crossover?

I've been looking into building an active crossover; if you'd like links to some things I"ve found so far, just let me know.

Nope, I don't have an active crossover.

Yeah, please post your links here.

I'm not prepared to build or buy and active crossover yet. I'd probably start with purchasing the additional amp(s) needed to power the drivers. I'd want tubes on the midrange and highs, so for a 3-way speaker, I'd need an additional tube amp and a SS amp for the bass. I'd prefer tubes on the bass, as well, but that's probably more costly.

If you guys run across any "bargain-priced" multi-channel tube amps, let me know.:p

Face

What speakers will you be using?

clearwave

Early B. wrote: »

Question --

Is it possible to pursue an active crossover without incurring the expense of new speakers? In other words, can you rip the guts out of an existing pair of speakers, add extra sets of binding posts, if needed, grab an external crossover and some amps, and be done with it?

Absolutely not. The transfer functions of the electronic crossover have to take into account all the factors that go into the speaker design; including the natural roll off of the drivers, baffle step compensation, impedance, on and on and on. There are active crossovers that can do this, but you will need measuring equipment to input data into a crossover software modeling program to create the active crossover design, just like a passive one. A one fit approach or standard LR2/LR4 active crossover will be a serious downgrade unless properly designed for the FR of the drivers in the intended box.

An active crossover for subwoofers is a different matter, but even that requires careful matching of the rolloff of the sub in room to match the HP and LP sections of the system's design.

Systems

I believe active systems have some real performance advantages vs passives,and I use a fully active set up myself.But as mentioned using an active xover without having detailed info on the drivers and how they perform in their enclosures,then you are shooting blind and your chance of success are low.

Heres is the manual to one of the xover boards I use.There is some great info on how correctly implement active xovers.http://www.delta-audio.com/Active_Filter_Four/Active_Filter_Four_manual.pdf

Early B.

clearwave wrote: »

Absolutely not. The transfer functions of the electronic crossover have to take into account all the factors that go into the speaker design; including the natural roll off of the drivers, baffle step compensation, impedance, on and on and on. There are active crossovers that can do this, but you will need measuring equipment to input data into a crossover software modeling program to create the active crossover design, just like a passive one. A one fit approach or standard LR2/LR4 active crossover will be a serious downgrade unless properly designed for the FR of the drivers in the intended box.

An active crossover for subwoofers is a different matter, but even that requires careful matching of the rolloff of the sub in room to match the HP and LP sections of the system's design.

OK. Gotcha.

Jed -- are you planning to build a set of active speakers anytime soon?

ben62670

GV#27 wrote: »

I believe active systems have some real performance advantages vs passives,and I use a fully active set up myself.But as mentioned using an active xover without having detailed info on the drivers and how they perform in their enclosures,then you are shooting blind and your chance of success are low.

Heres is the manual to one of the xover boards I use.There is some great info on how correctly implement active xovers.http://www.delta-audio.com/Active_Filter_Four/Active_Filter_Four_manual.pdf

Yep. Mine is active, and my mids are too hot. If I turn the HP down the top end suffers. This is using flat drivers:(

Face

ben62670 wrote: »

Yep. Mine is active, and my mids are too hot. If I turn the HP down the top end suffers. This is using flat drivers:(

Yes, but you now know what needs to be done, right? Get to it already.

strider

So far, I've found kits that look interesting from these guys:

Marchand Electronics

Welborne Labs

Audio-kits.com

And good info from:

Elliott Sound Products

http://sound.westhost.com/project09.htm

http://t-linespeakers.org/linx/xolinks.html

I'm just starting to look into them, I'm sure the other guys that chimed in have way more practical experience. I'd like to integrate some low end support for my fullrangers using an active XO to biamp, looks like there's a few things to consider to do it right.

ben62670

Face wrote: »

Yes, but you now know what needs to be done, right? Get to it already.

Get an EQ:p I think you may be referring to room treatments.

Systems

ben62670 wrote: »

Yep. Mine is active, and my mids are too hot. If I turn the HP down the top end suffers. This is using flat drivers:(

One thing you might try is adding some time delay to the tweeter.This should help with the blend between the midrange and treble.Being as your tweeter and mid -woofs are on a flat baffle the tweeters acoustic center will be closer to the listener.Therefore its output will lead in time that of the mid woofers causing a phase disparity.The circuit to add delay is dirt simple, just use one of your OPA2134's and a few passive parts and estimate the amount of delay needed.http://www.linkwitzlab.com/filters.htm#4

ben62670

Well I have the new tweeters in place. I played with reversing the polarity of the tweeter with the nippled Vifa, and it did not work. I figured that the new dome tweeter built on the same motor structure would have the same results in the lower end of the spectrum. Well I went upstairs and flipped the speaker wires and friggen eh it worked. Allison Krauss is the hardest material I have that just loves to show flaws in speaker design at the crossover point. The Silver Flute drivers are know for break up at somewhere in the 2-2.5k range. I have run these drivers letting them roll off naturally and there is a peak around 5k, but I did not hear the 2-2.5k distortion that I have read about on the DIY sites. I may leave it at 3.3k.
This isn't a thread jack. It is an example of why sometimes a plain active XO just doesn't work.
Ben

Systems

Yep sometimes the combination of the drivers relative poistion on the baffle and the frequency of their natural rolloffs will cause them to be somewhat out of phase.So its important to try both normal and inverted polarities.

ben62670

I tell ya what. After 2 years of non stop messing with speaker design it is not the simple is it a 4 ohm, or 8 ohm driver to make a crossover I thought it was when I first started playing this game;) You can get decent sound sometimes if luck is with you, but to get accurate good SQ it takes lots of time and research.

Systems

ben62670 wrote: »

I tell ya what. After 2 years of non stop messing with speaker design it is not the simple is it a 4 ohm, or 8 ohm driver to make a crossover I thought it was when I first started playing this game.

Yeah the nice little passive xover formulas don't work well because they assume the speaker is just an resistor.:eek:Atleast with actives the impedance is a non issue.

ben62670

Yeah early on I thought I could just figure out the impedance of a driver at the XO point, and use that to figure out the XO, but it's usually not that simple:(

clearwave

Early B. wrote: »

OK. Gotcha.

Jed -- are you planning to build a set of active speakers anytime soon?

Not anytime soon. It sure would be cool though, if properly designed etc. My business is really starting to take off, so I'm just keeping up with the designs I've got in stock right now, and designs I want to complete my model lineups. After that, who knows; an active design might be in my future. I've toyed with the idea of an all out dipole system, but the passive monopoles I've worked with lately sound so good it makes me wonder if it's worth it.

SlowcarIX

Early B. wrote: »

Question --

Is it possible to pursue an active crossover without incurring the expense of new speakers? In other words, can you rip the guts out of an existing pair of speakers, add extra sets of binding posts, if needed, grab an external crossover and some amps, and be done with it?

3 inputs, 6 outputs

Systems

That DCX 2496 is a wonderfull little tool for those wanting to try the active approach.I would like to have one to experiment with. Does'nt your CS2 's come with one of these with custom filter settings?

SlowcarIX

yep - iirc 6 or 7 presets.

Early B.

I suppose it will take a while for someone to build it, but I'd be interesting someday in purchasing a set of 3-way speakers along with an "affordable" audiophile quality active crossover without all of the bells and whistles. I understand that a heavily modded Behringer is decent, but how about introducing a crossover that doesn't require a Ph.D. in electrical engineering to figure out all of the freakin' features.

Ben -- I'll give you 12 months to build it. Bone up, brotha.

Systems

Hows about these?I'll sell them to you but for pick up only.:D It's time for me to build something a little more ambitious,like maybe a pair of Orions.

ben62670

You built those GV?

Systems

ben62670 wrote: »

You built those GV?

Yes, they are the ones listed in my sig.I built them about 5yrs ago,though there has been several driver changes in that time.

ben62670

Very nice. When I get back on my feet I would love to have something I made actually look good.

strider

strider wrote: »

Elliott Sound Products

http://sound.westhost.com/project09.htm

Somehow I ended up posting this link twice. I meant to include this one:

http://www.snippets.org/filters/crossover.htm

hoosier21

Early B. wrote: »

I suppose it will take a while for someone to build it, but I'd be interesting someday in purchasing a set of 3-way speakers along with an "affordable" audiophile quality active crossover without all of the bells and whistles. I understand that a heavily modded Behringer is decent, but how about introducing a crossover that doesn't require a Ph.D. in electrical engineering to figure out all of the freakin' features.

your out of luck, cheap simple and easy to use, not available. How could there be a one size fits all, mass produced, 3 way crossover that you could just hook up to any set of drivers and it work right?

The Beringer is cheap, but has all those settings so you can use it with any set of drivers and tweak the sound to get it right. If you are not willing to figure it out, your out of luck I am afraid.

ben62670

Thanks for the link Ben. Shipping kills DIY projects. I am not interested in the kit as a whole, but just the parts with all those OpAmps different R's and C's is excellent. I love active for DIY:)
Ben

strider

ben62670 wrote: »

Thanks for the link Ben. Shipping kills DIY projects. I am not interested in the kit as a whole, but just the parts with all those OpAmps different R's and C's is excellent. I love active for DIY:)
Ben

No problem. I'm not sure that guy's selling his kits anymore, IIRC the most recent update is from '01. It does have a lot of info, though.