Crossed at 2650.

Its a long building process. What else do you want to know?

Marlboro

So there is no sub woofer here. There are three separate power amps and two 12 inch woofers that are capable of handling 17hz to 300hz with out a problem.

My problem with Selah is the use of 8 inchers. They really won't cover the deep bass, and they get thin in the lower midrange. Now when you use a lot of them, this is a bit blurred, but..... I can't believe that their transient response can be as good as a three inch speaker; the big cone just can't move fast enough.

I've not heard the Selah so I can't say, but we have basically different design characteristics. However, I'm using domes for two reasons: 1. I like dome tweeters, 2. Domes fit in my price building model. You could use ribbons, but I would NOT use any one except the B&G Neo 3. You would need a line of them at least 35 inches big.

You can't buy the mid range anymore, but there is a good HiVi model which I would recommend as a replacement---more expensive, but it would fit the design parameters.

As a bass amp, mine is a two channel one with 350 w/ch. I picked it up on ebay. Its not the best amp for upper mid and high frequencies, but its great for the low ones, and never even gets warm. For the mid range 165hz to where you cross to the tweeters(2600 to 3500), you need a power amp of about 150 - 200 watts/ch, looking for something HEAVY showing a really good power supply and a big capacitor. For the tweeters, any amp will do. I have an old Sherwood receiver I use for them that puts out 60 w/ch, and is light with a light power supply.

PVC pipes are simple 4 inch thin wall white drain pipe. Very cheap at Home Depot in the States.

I bought my Rane AC23 on ebay used for about $115, new they run $400, but they are built like brick sh*t houses, so there is no need to buy a new one. If you want a digital one, so you can have a slope up to 88db/octave or anything in between, you can get a Behringer for about $230.

An equalizer is worthwhile having. You need a constant-Q model, and at least 2/3 octave, 1/3 would be better but I couldn't afford it in my budget. Expect to pay on ebay about $175 for a two channel constant Q DOD or Rane analog equalizer. Mine is not currently in the loop.

You need a measurement mic, behringer 8000 or Apex 220, and software.

For woofers I use a DVC 12 inch Goldsound which retail at about $129 now. Any other one by Dayton for the same price around $130 or so would work. You need two of them.

You need a preamp. I use a Kenwood B-1, but a Kenwood B-2 would be even nicer. Any pre-amp that works for you would be fine.

That's a smattering of what I needed---maybe a quick 10% of the total info you need to design it.

Marlboro

Marlboro

The problem here is probably that I said I did it really cheaply, and most line array systems are done very expensively. Saying that I can have a system that really kicks butt, with all the benefits of a full 3-way line array for $1300, INCLUDING tri-amping, 1200 watts RMS, electronic crossovers, 2/3 octave Constant Q equalization, and includes an Apex 220 calibration Microphone, and Fuzzmeasure computer software, and a floor to ceiling system done in Oak, is a very bad thing to say. Very bad. it makes people very angry. It makes them angry when they think what they might have paid.

Sorry to say, but there are no response problems that I can hear. The system kicks ass playing everything from Bach organ to solo violin to Saxophone Jazz to Little Feat and Led Zepelin.

I'm not some 22 year old kid in the music department. I have near perfect pitch. I play the violin and the Saxophone. My father had degrees in music from Columbia and Julliard and my sister and brother in law have degrees in music performance(cello and Organ.) I still have local SEASON symphony tickets. I know what quality music sounds like both in live performance and how it usually doesn't sound like that in speaker systems. And while being 58 may have its detriments(I can't run quite as fast for my 45 minute run), it also has the benefits of more than 40 years of listening to speaker systems.

Think what you want. I know what I might be thinking If I were you, but you won't. I've paid close attention to Jim's design parameters and followed them. I just did it cheaper and with a 3 way than the usual TWO way system.

The spacing between the drivers is 5 inches. This means that the crossover to the tweeters cannot exceed 2712hz according to Jim's design parameters. My electronic cross is at 2600. The tweeters have their flanges cut the spacing is .9 inch which means that comb filtering might start around 15066hz, quite a bit above audibility.

The real problem for you, Rick, is that I said I did the mid ranges with a 17-3 inch mid bass woofer, which was sold on PE for a measly $4.00, and 30 -tweeters which are sold on PE for a measly $4.10.

Of course you are going to say its poorly executed.

My God, if you don't say that then you cannot justify charging people what you do for a set of speakers that don't even go to the ceiling, and only have 8 woofers and 8 tweeters, and don't even have electronic crossovers, much less the included pre-amp, three power amps and equalization.

Very Poorly Executed? What you may think, ACTUALLY, is that I should be executed for saying it outloud. Most people won't. It takes so damn long to build the systems that almost no one will build one from scratch like I did, and so almost no one around in the DIY speaker community can make comments like I did. Commercially designed Line Arrays have almost no competition from the DIY community.

Marlboro

Perhaps not as bad as you are thinking. He is using 3" diameter mid-woofs with 4" pipe loading for each one. It would have been better to locate these drivers closer together so that the center to center spacing was smaller (I'm guessing about 5" c-t-c in his design). While with his crossover at 2650 Hz would create some potential combing issues for a low slope crossover, his active crossover likely has a high enough slope to minimize the crossover overlap region between the mid-woofs and tweeers. He does trim the flanges on the dome tweeters so that their c-t-c spacing is reduced. Hence, he pushes the coherent frequency coverage for the tweeters higher than you would have without those trimmed flanges.

He is a student of my white paper and suggestions which is a good start toward a cohesive line array. I'm sure that his next project will be improved but for a budget array it is a very good start IMO.

Jim

Based on what we've measured with smaller drivers and a similar spacing there will be frequency response problems. The tweeters will simply not cross low enough to avoid this.