DIY speakers vertical array a la "pipedreams" syst

Fred, once again thanks for the advice, lots to take in but it all looks to be great "fun". Maybe the voight pipes from your site would be a good primer, but if I can find a suitable driver for open baffle that I can afford I will give it a try. Eminence coaxials with associated tweeter seem to fit the bill. From what I gather, the Bastanis simply has a resistor on the tweeter and that's it for a crossover. I could add a pair of active subs later.

The full range driver is a viable option, but I'm skeptical about getting one to sound good with an open baffle. Fostex drivers and the like have so little X-max (0.6mm for the FE-167) that they can easily be driven to excess distortion levels without the control of a good enclosure. Even with a bass reflex enclosure you're going to hear distortion at fairly modest volume levels.

If you decide to use a Fostex here's a link to Bob Brines' web page. I heard his FT-1600 speakers at the Great Plains Audio Fest and was very impressed - they seemed to solve the bass problems I have heard with Fostex and Lowther drivers. He will sell just the plans, a flat pack kit, unfinished mdf enclosures or completed veneered speakers. The enclosures are not complicated and should be easy to build from the $25 plans http://geocities.com/rbrines1/

Another option I highly recommend is Wayne Parham's two way Pi speakers. I just completed a pair of 3 Pi Theater models which I really like, and at 98dB efficiency they sound really good with Paramours. If their $240 ea price is over your budget consider the 95dB sensitivity Two Pi towers at $80 each for the driver and crossover kit. I heard this one too at GPAF and it's amazingly good for the price. All these speakers have bass response that would shame any single driver speaker. http://www.pispeakers.com/

Thanks Fred for all the info and advice! I've been scouring the diy forums and pages like yours trying to absorb as much as I can, kind of daunting sometimes. My goal is to be able to use a pair of Bottlehead amps or similar SET to drive whatever I build. I'm wondering if I shouldn't just try a full range driver on an open baffle with bass handled by a sub, like the Bastanis, to get my feet wet before trying to tackle a line array. Any thoughts? Nice work by the way on your page and all your speakers.

I'm not aware of any open back line array plans. I had tried to build a pair using ten Parts Express 4.5" Vifa "buyout" woofers with a single tweeter and they sounded terrible, but that's probably a product of my design incompetence rather than a generic problem with open back arrays. If you're interested in arrays you should read Jim Griffin's white paper on that topic at http://www.audiodiycentral.com/resource/pdf/nflawp.pdf

After building three nearfield line arrays I'm convinced they are superior to point source speakers in several regards that are discussed in Dr Griffin's paper, but there are two offsetting disadvantages: 1) If you use quality drivers they are expensive, and 2) The enclosures are a much bigger project than smaller two or three way speakers. The driver quality thing is obvious - sixteen $100 woofers and 16 $118 ribbon tweeters are more expensive than two of each:) The enclosure construction issue becomes obvious when you have to lift a 4X8 sheet of 1" mdf on to the table saw roller tables and guide it accurately throught the saw. But when you have finished the project and listen to the completed speakers you will know it's worth the extra effort and expense.

Regarding the cost, I divide line arrays into three categories: 1) The obscenely expensive mainstream products like the Pipedreams and the Epiphanies. 2) The non-mainstream high end products offered by Selah Audio and GR Research, and 3) The DIY projects that use budget drivers.

If you have the money definitely choose alternative #2. I have heard Rick and Danny's arrays. They sound really good and even as completed ready-to-play speakers sell for less than half the price of the mainstream products. If you don't have $2,500 or more for a DIY enclosure kit, you are limited to alternative 3.

I'm aware of several budget DIY line array projects. Probably the best is the Linus I, which is no longer offered, but Jim Griffin will email you a copy of the plans for the asking. The Linus I uses twelve 5" MCM aluminum cone woofers (the shielded version of the driver that was used in the Bottlehead Straight 8) and six Silver Flute planar tweeters per side. The parts for this project will cost about $600, most of it for the twelve tweeters.

To get below the $600 cost you need to use a single tweeter instead of a planar array. I did this with the Fredarrays. It's not the best choice, but the single tweeter mated with the woofer array better than you would expect. Several people who heard the FredArrays at the Great Plains Audio Fest were impressed, one so much that he later bought them from me. I plan to build another pair soon. This time I will use the same Silver Flute woofers which, at $12.50 each by the case, are an incredible bargain and sound better than the $25 Vifa TC-series woofers they compete with. I want this one to be more SET friendly and plan to use eight per side to get a 16 ohm impedance. I also plan to use a better quality tweeter than the $12 MCM titanium dome in the original FredArray. possibly an Eminence compression horn.

The next step down the ladder would be to with for Parts Express to come up with another Vifa 4.5" buyout offer. These ususall go for $5-7 and sould pretty good. There's a good example of an array using these at
http://www.lonesaguaro.com/speakers/array/array.htm

The next step down from there would be an array using dirt cheap parts like these 79 cent Parts Express "factory buyout" tweeters at http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=279-010

I have some doubts about this extreme budget level. These tweeters have to sound terrible, like the tweeters in that Honda with a fart box subwoofer and cheap tweeters that pulls up next to you at the light with the windows open and rap music going full blast, and an array of 20 will sound like 20 spittng tweeters instead of one. Just my two cents.

http://www.geocities.com/dmitrynizh/labaffles.htm
This page has a lot of great info on open baffle and line array theory as does the Linkwitz page for anyone else interested in these designs. I think it would be a great project that hopefully would achieve great imaging similar to planars, but with the bonus of higher sensitivity and dynamics.

Can anyone help me figure out how to send Fred an email at that page, I don't see the link. Thanks

Essentialaudio, I don't disagree with your priorities, I just don't expect everyone has the budget for a top tier speaker.

Getting a young guy or gal into a DIY speaker that keeps the light burning for high end is a very worthwhile idea.

When I was very young, I began with a budget of $129.00 to built my first amp and preamp for my dream stereo system. If my only option had been something "world class," I would have never ventured into high end. I could not have afforded it.

That's all I meant.

Albert, no dispute about the attractive price and the idea of more folks getting into high end, but you have to weigh the pros and cons...coherency is a high priority from my biased perspective...

Essentialaudio, agreed, but the FredArray looks like (after quick calculations) to top out around $750.00 for the pair (plus sweat equity). That's less than a pair of Vandy 2's.

The idea is not to compete with Pipedreams, they already have their reputation established. This is a hobby site and hopes to involved people with hands on projects. I hope he catches on, we need more converts to high end.

The oft-overlooked issue is driver matching. Pipedreams does it the best they can which is why their speakers are so expensive. Hook a couple of drivers together and shine a strobe light on them with a signal generator to do a frequency sweep and you'll see them go out of phase with respect to each other. The problem goes up exponentially as the number of drivers increases.

Thanks for the link, that does look great, I worry a little about my cabinet making abilities so I thought a open baffle design would be easier but I think it might be worth the extra effort.

>http://FredT300B.smugmug.com/Hobbies
Sean
>

Looks like an incredible project and priced where most anyone can afford a pair. I like the web site too, with the ability to click and view all the stages of Fred's progress as he cut and assembled, all the way to the final product with improved tweeter.

Makes me wish I needed another pair of speakers.

Here ya go, Fred is a great guy! Maybe he can
help ya out.

http://FredT300B.smugmug.com/Hobbies

I attended the Great Plains Audio Fest in Tulsa back in April. A guy from the Houston Audio Society had a DIY vertical array that could be built quite cheaply. He used a low cost mid/woof and an inexpensive tweeter. I'm not sure of a website address, but type Fredarray into google and you should come up with it. It was quite impressive for it's low cost. He drove it with a DK design amp. I saw a post of his on Audiogon a few days ago, so maybe he will chime in here.

I'm wondering if you ever found any plans for a line source dipole. Or if you found it was a bad idea, I've been thinking of doing something similar.

Drop an email to Roger Russell, I am sure he would love to discuss tweeter tower designs and theory behind them with anyone.

Bill Fitzmaurice has designed a "mega low-budget" line array using "throw-away" drivers from Parts Express. The total cost for drivers is phenomenally low ( under $100 ) and according to what he's "leaked" about the design, it is appr 99 dB's sensitive. Probably not the finest in sound, but for someone that wants to experiment with this type of project, i doubt if you could beat the "fun factor" and education achieved through the building of such an inexpensive project. Sean
>

In addition to the GR-Research Alpha LS kit that was designed by Danny Richie, you may want to talk with Rick Craig at Selah Audio. He also sells some line source array kits. Both Danny and Rich are great to talk with.

The GR Research people sell a well designed kit (link provided in my previous post) and include plans for the cabinet. You could email or call about open back design and see what his experience is.

As for shopping, I thought the price was great. $1995.00 for 16 BG ribbon assemblies and 18 woofers, plus all the crossover parts. You might do better but this way the design is worked out and leaves the creative cabinet, finish and other fun stuff to you.

I even considered this for myself I though it was such a good deal. I really don't need them since I already own Soundlab U-1's but the fun factor attracts me.

As for performance, I have not heard the kit but the Epiphany speakers showed great promise, even under show conditions.

ok
thanks for the input

what do you think about the performance of this kind of system?
wich system where you able to listen to?

then, do you have any links for drivers?

i would really like to do one myself, since it is much much easier to do than an ESL :p

i ampretty sure i would be good to go with a openned back end style ..

Yep, considered that design and did research. My trip to NYC to cover HE 2004 for Audiogon stimulated me even more.

The Epiphany with Tenors really got me going:

http://www.epiphanyaudio.com/

Then I found this designer (here, near Dallas) who offers very reasonable kits and access to fancy cabinets.

http://www.gr-research.com/AlphaLS/Alpha.htm

Considering these are ribbon top end, very efficient to drive and great looking, this could be exactly what your looking for. Good luck.