Building a reference active 3-way speaker for high SPL

[Ricren]

Hi folks,

I need a piece of advice with this:
I’d like to build a high quality 3-way speaker for monitoring purposes that can output high sound pressure. (110 db).
Recently I’ve been modifying an old Urei speaker with the addition of a digital crossover and tri-amplification. The experiment went so well that I’m thinking, that perhaps to build a 3-way monitor speaker is not an impossible thing after all. I do not have the knowledge to choose the drivers and design the box, however. I have a few measurement devices and tools that can help. I’m not great building enclosures, but I can try.

So if anybody can help with comments or advice would be great.
The speaker class that I’m approaching is like this Dynaudio baby:

http://www.dynaudioacoustics.com/Def...846&AjrNws=603

A tri-way active monster with crossover points at 300 and 2500 Hz and 1200W of power plus extensive DSP. I think I could handle the electronic part of the project, but for the speaker enclosure and drivers I do not have a clue!

So let me introduce a few reliminary questions:
1-How do you like the proposed design to “clone” (Dynaudio AIR 25 speaker) Any possible flaws or improvement?

2-Can you recommend any drivers? Pity that Dynaudio do not sell the raw drivers anymore. I’ve heard that Vifa or Skan Speak are great, too.

3-Do you remember any related DIY project that could be used as a reference? Not need to re-invent the wheel, right?

Thanks for your time, any advice would be greatly appreciated.

Ric

[Nappylady]

If you're going for SPL, then you should look at JBL's offerings.

My ideal active monitors would be 2-way, with a 15" 2226 on the bottom (or 6 ) and one of their horns on top. Sealed, vented, not sure.... nice chipamps inside to power the thing.... heh, this could be fun!

Actually, perhaps a better woofer choice would be the 15"er that's at partsexpress right now... the limited run one... it's like $80 less and has higher total displacement.

I really don't think 3-way is necessary if you use a good horn that can get down to 1000hz, but *shrug* some people get bent out of shape about directionality and such.

I'm not an expert in either area but... this sure sounds like a fun project! I'm going to pay attention...

[leadbelly]

Originally posted by Ricren
3-Do you remember any related DIY project that could be used as a reference? Not need to re-invent the wheel, right?

There's a project that is close to what you are describing, a passive WMTMW design called the PX with supposed superb clarity at high SPL, that Wayne J at speakerbuilder.net will publish soon. The DIY version uses a Vifa ringradiator, Audax mid, and Usher woofer to get the budget to $1K. The commercial version uses Scan Speak ringradiator & woofer plus the Audax mid IIRC, but the design of that one won't be published of course.

[Vikash]

Building a reference active 3-way speaker for high SPL

Do you remember any related DIY project that could be used as a reference?

http://www.griffinspeaker.com/

http://member.newsguy.com/~stigerik/html/audio.htm

[Ricren]

Originally posted by Vikash


http://www.griffinspeaker.com/

http://member.newsguy.com/~stigerik/html/audio.htm

Tks for the link. Interesting. It was a surprise to realize that they are using the same driver that I used for my subwoofer. Nice driver. Not cheap.

"The 460 mm (18 in) long-throw paper pulp coned woofer comes from RCF in Italy, a company owned by Mackie. The driver is chosen for its extremely high output capability, low distortion and suitable Thiele-Small parameters."

So basically they use a D'apolitto MTMW config with crosover freq points at 130 and 1700 Hz. The woofer is almost used as a subwoofer. They even sell another model without this "sub-woofer".
I heard about Seas driver but that tweeter brand (stage acompany) is new for me. I'll serch for pricing on those units.
cheers

Ric

[Variac]

Stage Accompany are planar tweeters that handle lots of power, are efficient, and are reputed to sound very very good!

They are used in PA sound systems as well as monitors.
I've heard it's best not to use the horn option

Price? around $600 US each! There had to be one bad point!!

I think they would fit your plans very well

[Ricren]

Originally posted by Variac
Stage Accompany are planar tweeters that handle lots of power, are efficient, and are reputed to sound very very good

Price? around $600 US each! There had to be one bad point!!

Aja! That will be 3K in tweeters for a 5.1 system. I think I can live with that (barely...). Besides a web search indicates that everybody have a good opinion on this tweeter, plus it can be crossed fairly low (1700-2000 Hz). I remember seeing something similarly shaped on the ADAM monitors. And people really like those boxes.
I do not have prices for the Seas drivers. I'll keep searching.

Ric

[Variac]

The Seas drivers are listed at $162 ea at Madisound.com

[planet10]

A 3-way built around an Audax PR17 (or the PHL spawn) would give you a lot more efficiency than anything mentione so far, and they are no slouch in the Sonics dept.

An active system with the digutal XO really gives you flexibilty wrt drivers... the Stage Accompany is a beauty. AFAIK a spin off is Alcons. But any number of nice high efficiency horn tweetrs exist... thn bass to match. A set of Llambda 15s would be my pick.

dave

[Ricren]

Originally posted by Nappylady
My ideal active monitors would be 2-way, with a 15" 2226 on the bottom (or 6 ) and one of their horns on top. I really don't think 3-way is necessary if you use a good horn that can get down to 1000hz

I understand what you mean. Apparently, for efficiency nothing beats a horn. However I already have a pair or monitors with horns on them and I've been using this setup for such a long time, that I feel it's time to try something different.

Ric