PE is supposed to come out with a very low distortion RS series 3 inch midrange with high Xmax which might raise the bar on my current design, and then I could go with them. I've not seen a dome tweeter of higher quality that can be made with a center to center distance of closer than about .8 inch that fits the parameters of the current design. Using thirty of them per side drops the distortion down to pretty low levels. Using thirty tends to flatten the FR over an average.

If I changed the design to a larger midrange then I could buy a more expensive one, but then that would require that I go to B&G Ribbons which are not part of my design since I prefer the tweeter sound of domes, and to get a similar low distortion I would need to have a double row of the ribbon tweeters which I'm not sure is possible. I would have to lower the crossover, and the domes would no longer work. I would need larger diameter tubes or would have to go with Sono-tubes.

I could upgrade the amplification equipment, but I would only do an ultimate system if I could hear a difference. I've no evidence that I could.

I'm not sure this answers your question. My design was very carefully worked out initially based on very specific parameters which I designed at the beginning. I spent a lot of time in the design phase before I even began building.

For me, the current design is at the ultimate level. Another design might be better, but I've not looked into modifying the design since I continue the be extremely happy with the sound I have now.

I'm one of those people who when I reach the 96% level, I don't spend all my time trying to inch up to the 96.5% level, but just spend my time buying music and listening to it.

Marlboro

With the inherent efficiency of the arrays and the amps properly matched, 12w is more than enough even for blasting "Tusk" at concert levels.

Not that I need more bass, just that the bass would have the same level of low distortion that the rest of the system has.

Marlboro

Say at 24 dB, and 48 dB per octave?

Tom R.

At 48db/ octave you might be able to go 1900, but I would go lower than 2200 myself.

Marlboro

1) You can build a very good sounding line array using mid priced drivers, but those drivers individually are going to have some compromises that can't be completely overcome by using them in an array. The Dayton Classic midwoofers, for example, are very good "bang for the buck" drivers, but individually or in an array they are going to have more midrange distortion than similar size Aurisound ceramic cone or Seas Magnesium cone drivers.

2) One mistake I sometimes see in amateur speakers is the use of incompatible drivers. One of my rich Houston Audio Society friends recently asked me what I thought about building an array using an array of twelve very expensive 8" woofers alongside an array of Raven tweeters. Great drivers, but the Raven tweeters he was thinking about using won't play low enough to cross to the 8" woofers, even with a high slope electronic crossover. I suggested that (if he had that much money to spend on a line array) he should contact a qualified designer and commission that person to design a cost-no-object array for him from the ground up.

3) A three-way design with a sealed midwoofer array is a requirement for the ultimate array because a two-way design, even if it is ported, won't play low enough and still have state-of-the-art midrange. With a single midwoofer or an array of midwoofers there's a tradeoff between midrange clarity and bass extension. You can build a good sounding affordable two way array that will play into the low 40's, but the "ultimate array" would have separate subwoofers. And if you're designing the midwoofer array for use with a subwoofer you might as well make it a sealed design for better integration. For a more complete explanation of the bass extension limitations of an affordable two way design see Jim Salk's Audio Circle thread about "the $2,000 challenge"
http://www.audiocircle.com/circles/index.php?topic=52247.0

4)Digital signal processing and crossover are a good choice because even the high quaity drivers you are using have some compromises at their frequency extremes, and DSP provides more control over those anomalies plus the elimination of the signal degradation and phase issues that are inherent in a passive crossover design. Separate amplification is a requirement of an active crossover, so that's a non-issue.

That's about it. You could use a four-way design, especially if you wanted to make the speakers as expensive as possible, but I doubt the added complexity of a four way would improve the sound quality.

You can't use tweeter domes in an array with mid ranges above 4 inch diameter. The mids won't go high enough and you lose much of your upper midrange. So you them have to use ribbons or planars, and you won't be able to use more than 6 or 8 of them. This will cause you to lose the advantage of very low distortion of a huge line of tweeters.

In my opinion, the main reason for not using dome tweeters is that you simply can't use them when you use mids above 4 inch in diameter. Your midrange speakers have to go reliably to at least 2500 hz to get the flexibility you need in design. Everything has to fit together.

Marlboro

If you are buying it, then you will pay top of the line prices for everything, and you will have to add on the standard 40% to 60% to even 100% gratuity for the builder/designer/manufacturer.

If you are building it yourself, then you can afford to wait until the speakers that you have designed it for come on sale, you can wait until the electronic crossover and amplifiers come up for a good price on ebay, and you can do the whole thing without any gratuity to the manufacturer for his profit. You can do things in the design that would be totally not cost effective for the manufacturer.

But if you are building it yourself, you will actually have to study and research everything you can find on the subject, buy books, ask people, and make a full study of how to do the whole thing. You will not get this from any one source, and most of the people who know how to do this are manufacturers, and won't tell a DIYer how to make their product for much cheaper.

So you have to decide how much work you are willing to do or how much money you want to pay.

MARLBORO

Tom R.