DIY active crossover Line Source speakers

thayerg · « **on:** 1 Jan 2004, 09:00 pm »

I've decided to plunge into the DIY audio realm (morass?) by building a pair of line source (LS) speakers which can use either active or passive filtering, configured by jumpers at the terminals the way Linn does it. I don't know the first thing about circuit design, which limits me to purchasing a kit. I'd like to use the Behringer active crossover and maybe 4 Wave 8s for amplification. Buying one of these kits is a complete act of faith amd so I've set down my initial responses below, ranked in the order of how the kits seem to stack up to me (highest first).

1. Selah LS-2

Pros: price, 10 5.5 in. non-metal mid/woofers per side, line source tweeter array, small size, ribbon tweeters
Cons: No speaker grill

2. CSS audio Needles
Pros: The LS design presumably overcomes the limited dynamics of the otherwise remarkable TB driver. Size is right. The price is right considering the brutal cost of the ribbon tweeters.
Cons: tweeters aren't line source, no grill, lilmited info available on website. Still I'm very intrigued. This design could be a home run.

3. Bottlehead straight 8s
Pros: price
Cons: tweeters not line source, hocus-pocus with the woofer 'treatments', huge cabs. It could also be argued that these speakers aren't truly line source anyway. But I'm willing to believe that they sound good.

4. Everything else. Prices put the kits out of my budget. Unless I'm missing something.

I'd be grateful for any feedback from anyone who has done any of these kits. I want to include the passive crossovers as reference points for configuring the active xover--ie see how much better I can make the speakers sound in an active configuration.

Happy New Year.

Thayer

warnerwh · « **Reply #1 on:** 1 Jan 2004, 09:06 pm »

Just did quite a bit of research myself into designing and building a line source speaker. Let me assure you it's much more complex than it appears and much knowledge and experience is required to do a good job. Go to the Parts Express site and check out the speaker building forum. In short unless you have years of experience then buying speakers in a kit form is definitely the way to go. One of the biggest problems is crossover design. This can get real expensive due to the fact the theoretical parameters seldom work in the real world. Also the Behringer has been specifically NOT recommended to me for use in a resolving speaker. You should check out VMPS kits as Brian is an excellent designer and his speakers are consistently great for the money. Also Rick Craig of Selah Audio and Danny of GR Research would be worth talking to. I believe Danny is going to introduce a new speaker here shortly that you may find of interest. You can hardly go wrong with anything VMPS has to offer and there are plenty of people besides myself who will corroborate this.

JohnR · « **Reply #2 on:** 2 Jan 2004, 02:02 am »

The budget is $1k tops?

BTW would it be OK if I moved this thread into The Lab?

thayerg · « **Reply #3 on:** 2 Jan 2004, 03:36 am »

JohnR

Yes, that's the budget. And no, I don't mind if you shift the topic elsewhere.

I've done some more research based on warnerwh's comments, as well as reading up on active speaker designs. I've listened to the Solar 1.0 speaker, which I think is astonishingly good. But the increased dynamics and broader sweet spot of the line array design both appeal to me, plus the fact that that their efficiency brings them into the realm of low power tube amps. The best of all worlds without getting too esoteric.

IanATC · « **Reply #4 on:** 2 Jan 2004, 10:04 am »

There also an "excelarray" DIY project you can make? I have read amazing things about that.

JohnR · « **Reply #5 on:** 3 Jan 2004, 12:23 am »

Heh, the ExcelArray is well out of the budget, and doesn't look like it's available DIY anymore anyway

Thayer, I'd put the choices in the same order as you. The Linus is the only "true" line array... I don't quite understand the Needles concept, to be honest, I'd be interested to hear what you find out about it.

thayerg · « **Reply #6 on:** 3 Jan 2004, 06:56 pm »

johnR Thanks for reinforcing my take on the various kits. I spent some time looking at your photos and I have to say I like your minimalist approach, plus you seem to be having fun. Question: What, exactly, does the blue foam do behind the dipoles? Are you seeking to control the ratio of direct vs. dipole energy?

I've sent an e-mail requesting info about the Needles. I'm guessing they aren't quite ready for prime time.

JohnR · « **Reply #7 on:** 4 Jan 2004, 12:56 pm »

Heh, fun is right, but sooner or later I need to finish something

I was trying to absorb the backwave from the dipole. Didn't work, really, at least not low enough. The mids improved though! As I recall, that was a while back. Anyway, your posts got me thinking again about a solution for those Neos, I posted the basic idea of what I came up with in the GR circle:

http://www.audiocircle.com/index.php?topic=7165

And all it costs is money and time!

thayerg · « **Reply #8 on:** 5 Jan 2004, 05:47 am »

Thanks for directing me to the thread you started. I hadn't considered that the passive components might include a notch filter as they do on the GR Research designs. I'm still interested in doing the xover digitally and I suppose it wouldn't be too much more of a stretch to mimic the notch filter in digital eq.

I'd say that DIY audio is one place where having fun is better than finishing stuff. Unless you are trying to run a business.

gonefishin · « **Reply #9 on:** 6 Jan 2004, 02:10 pm »

Quote

I'd say that DIY audio is one place where having fun is better than finishing stuff

I'm learning starting to learn that myself. Oh...the projects are starting to pile up!

have fun!