AVS Forum banner
1 - 20 of 63 Posts

·
Registered
Joined
·
2,195 Posts
Discussion Starter · #1 ·

·
Registered
Joined
·
343 Posts

·
Registered
Joined
·
786 Posts

·
Registered
Joined
·
343 Posts

Quote:
Originally Posted by Rick Craig /forum/post/19577279


Yes, CNC unassembled cabinets will be part of the kit.

Wow, very cool! I wonder what they will cost?
 

·
Registered
Joined
·
1,083 Posts
Looks really cool.


If they sound as good as they look.... wow.
 

·
Premium Member
Joined
·
25,501 Posts
I wonder why they didn't space the two types of drivers closer; looks problematic.


Though maybe with the combined power handling of all those tweeters they can XO lower than one might think.


Hmm, can't find any 1/2" aluminum dome tweeters at PE.
 

·
Registered
Joined
·
786 Posts

Quote:
Originally Posted by dykz34 /forum/post/19577366


Wow, very cool! I wonder what they will cost?

Not sure what the price will be - a few details are still being worked on.
 

·
Registered
Joined
·
526 Posts
According to Keele, the horizontal directivity is actually quite wide and well predicted/controlled. The beamwidth looks much like an ellipse; somewhat narrow vertically, wide horizontally. IIRC, a good general rule of thumb is that smaller drivers exhibit better horizontal directivity than their larger brethren for the same frequency, so it stands to reason that a cbt of small drivers will have excellent directivity.


Noah--the drivers merely need to be within one wavelength ctc, so I don't envision too much an issue unless the crossover is a fair bit lower than I imagine.


The design is well publicized, and the components seem awefully similar to what Keele built his array with. So IMHO, what will make or break this kit will be the price. Curved cabinets and dozens of drivers are not an inexpensive proposition; people may be well inclined to go the buyout route. Although it would be extremely cool of PE to offer the drivers for sale, sans kit.
 

·
Registered
Joined
·
4,816 Posts
Well thanks stgdz!!

I was just wondering about the CBTs on another thread and you posted this. I am still wondering about one of these for a center channel.(smaller version of Montekays)


Is this the 3.5"?

$608 for just the 3.5's,... I wonder how much the tweeters would cost?
 

·
Premium Member
Joined
·
25,501 Posts

Quote:
Originally Posted by Starkiller4299 /forum/post/19579000


According to Keele, the horizontal directivity is actually quite wide and well predicted/controlled.

Doesn't mean much unless he was specifically talking about drivers of these sizes and spacing.

Quote:
Originally Posted by Starkiller4299 /forum/post/19579000


Noah--the drivers merely need to be within one wavelength ctc, so I don't envision too much an issue unless the crossover is a fair bit lower than I imagine.

That doesn't seem consistent with the badmouthing horizontally arrayed center speakers get for their horizontal response.


I think you mean "unless the crossover is a fair bit higher", as the lower it is, the longer the relevant WL.
 

·
Registered
Joined
·
1,125 Posts
forgot the mention I'm pretty sure the production version will also be fully active like the demo. So you need something like a DCX2496. And you need need a sub
. But shading resistors will come with the kit so you don't have to worry about any complex eq settings... should be very simple.
 

·
Registered
Joined
·
2,405 Posts
Quote:
Originally Posted by coctostan
I'm curious about the horizontal directivity of a CBT. Is it wide, narrow or in between? Is it controlled and/or constant?
Found some measuerments in the 'goody' files:

http://www.xlrtechs.com/dbkeele.com/...0Download.html


Some of the most enlightening measurements are of the one-way array, I believe the CBT45....


Very good reading. Don also will have a newer paper out soon detailing sims of straight v curved v delay curved and shaded v non-shaded for each. Would be great if someone would build one of each to measure, as Keele uses point sources for modeling, while we use finite sources to build with....


As far as predicted horizontal directivity, here is the page I usually would refer to:

http://audioroundtable.com/PiSpeaker...ges/11054.html


Or here:

http://audioroundtable.com/forum/ind...3306#msg_63306


Wayne Parham has some great crossover insight.


Basically, any 2-way CBT will have horizontal nulls, but since crossover points can generally be kept down in the 1-2kHz area, and C-C spacing between woof/mid and tweet can be kept VERY small, the nulls will theoretically occur at very wide angles, so much so that Linkwitz's formula may not be able to account for it (unable to give a more than 90 deg angle w/ the ArcSin function).


Unfortunately, I do not believe Mr Keele measured both woofer arrays and tweeter arrays at the same time at the crossover frequency in his "Practial Implementation" paper from Oct 2003. The Oct 2005 paper compares a 2-way convertional speaker placed above the ground with a straight and curved array, and lots of measurements were taken. They were one-way arrays, and so suffer high freq directivity issues off axis.


One of the posters in the downloadable zip file compares a one-way array with the Revel Salon. Lots of measurements....


My main question has always been how would the shading scheme be best and most economically implemented passively and yet still give a friendly impedance to somethng like an AVR (8-Ohm)??


Does anyone know how the PE Kit will do the shading? Multiple L-Pads? Series resistive elements?



JSS
 

·
Registered
Joined
·
1,048 Posts
Quote:
Originally Posted by stgdz
Saw this in the latest flyer
http://www.parts-express.com/cbt36/i...n=Catalog_2011


I wonder if they are going to include everything in the kit(boxes).
I believe the plan is to offer a flat pack, I'll have to check with Marshall. It would be a lot of holes to cut if you don't have a CNC.


Edit: I see Rick already responded, yes a flat pack. I haven't gotten to hear this speaker yet, the only CBT's I've heard are my center speaker and the huge ones Marshall built for their church in North Carolina. I may end up in China for Christmas but if not I'll try to get out to NC and hear this thing. (currently in Korea)


mk
 
1 - 20 of 63 Posts
Top