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.]

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]

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.

[GV#27]

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.]

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]

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]

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. :D

[strider]

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

Marchand Electronics (http://www.marchandelec.com/)

Welborne Labs (http://www.welbornelabs.com/acm.htm)

Audio-kits.com (http://www.audio-kits.com/page/page/4071180.htm)

And good info from:

Elliott Sound Products (http://sound.westhost.com/project09.htm)

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]

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

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

[GV#27]

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

[GV#27]

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.

[GV#27]

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]

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]

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?

https://www.rizing-online.com/upfile/item1/DCX2496.jpg

3 inputs, 6 outputs

[GV#27]

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.

[GV#27]

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?

[GV#27]

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]

Elliott Sound Products (http://sound.westhost.com/project09.htm)

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]

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]

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.

[ben62670]

I'll try to contact him. I had to spend a lot of coin to do my pre/phono pre just to get the right values. Now I have a ton of R's that I will probably never use, and I don't have R's that would be handy to mod XO slopes:(

[strider]

If he is still selling, lemme know. Right now I'm leaning towards one of the Marchand kits, but I'm really taking a WAG that a 4th order LR crossover will work in my situation. Something like the kit on the snippet link would be perfect to fool around with.

[treitz3]

I just got hooked up with a Clearview active crossover. It's variable and does a great job in the rigs I have heard it in. When it gets here, I'll let you know how it works in my rig Mr. EarlyB.

[ben62670]

I did the Marchand XO in my pre. It is a simple cheap kit. He has a program to figure out the slopes in case you want to mod it. They come with the BB2134 OpAmps now. All you need is a PS. A rat shack 12-0-12 transformer is fine if you mount it out of the box. The Marchand PCBs are top notch too.
http://www.polkaudio.com/forums/showpost.php?p=900306&postcount=38


I just got hooked up with a Clearview active crossover. It's variable and does a great job in the rigs I have heard it in. When it gets here, I'll let you know how it works in my rig Mr. EarlyB.
Send it down with Russ in Feb I'll test it for you for free:) Actually I would love to have something I can turn a dial on to figure out where I want to fix my XO point at.

[GV#27]

Actually I would love to have something I can turn a dial on to figure out where I want to fix my XO point at.Like this?http://www.behringer.com/EN/Products/CX2310.aspx Believe it or not I have heard reports of some using this inexpensive unit in very good systems with very good results. They can be had for $90ish.

[ben62670]

unbalanced:)

[GV#27]

unbalanced:)Yeah the balanced only input is a pain, but you could whip up some bal to unbal adaptors/cables in a jiffy.

[ben62670]

I have a car stereo XO that I used to use. It worked pretty well, but no 15-0-15. I don't know how that affects SQ, but it is good to be able to turn some pots to test with. I have a GSA-700 surround amp I'll post some pics of later. I am ripping the digital out and I took a 4 1/2" grinder with a cut off wheel to the board to steal the amps. That will be my new integrated pre DAC XO. The pot that came with the Adcom is a motorized 6 channel, and I am thinking of stealing the IR control unit from my remote volume control on my other pre. The amp section is like a 535 from what I can see. I may drive the tweeters for now with that and see what it sounds like. There are a couple naughty DC caps in the signal path that I may bypass or replace with better units. It will be for the highs so caps shouldn't hurt?

[strider]

Early, et al.

Found a pretty interesting XO project on DIYaudio while researching for my project. Basically an analog XO unit that's adjustable for order, frequency, and Q. Also has balanced and unbalanced inputs/outputs. I'm just wading into the thread, but looking at the schematics and PCB layouts on the first page it looks pretty promising.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=27651&highlight=