AudioNervosa

Systemic Development => Speakers => Topic started by: Hornologist on August 08, 2012, 03:10:03 AM

Title: Line Array tricks
Post by: Hornologist on August 08, 2012, 03:10:03 AM
Hi everyone, I am looking for tweeters for a line array. I have 2" drivers for the lower range ( up to 6000 Hz). It is almost impossible to find drivers smaller than 1". Could one of these tricks help ?
Will a waveguide like the http://www.bcspeakers.com/product.php?id=8 (http://www.bcspeakers.com/product.php?id=8) overcome the wavelenght limit, do they form a real array if stacked up directly ?
or could a ribbon tweeter or planar be used ?
Who has some experience in this field ? Thanks a lot Marc   
Title: Re: Line Array tricks
Post by: rollo on August 08, 2012, 06:48:17 AM
  You might want tp contact Danny at GR Research for some help.



charles
Title: Re: Line Array tricks
Post by: Face on August 08, 2012, 07:09:50 AM
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-1122 (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-1122)

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-1002 (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-1002)
Title: Re: Line Array tricks
Post by: Hornologist on August 08, 2012, 09:24:35 AM
@rollo : thanks for the hint, I will look at their site.
@face : these tweeters are amazing, by size, range and power.
Great advice, thanks a lot Marc
Title: Re: Line Array tricks
Post by: richidoo on August 08, 2012, 03:14:44 PM
The CBT array sold by PE uses inexpensive small "full range" drivers designed for laptop computer speakers. They are made by harmon, but I don't know much more about them. PE says they are Dayton part, but they don't list a part number, and apparently not available separately. They sound just OK. The Vifa will be better choice if you can afford.

http://www.parts-express.com/cbt36/ (http://www.parts-express.com/cbt36/)

The planars are another good choice, especially the longer ribbon units like HiVi RT2C.
Title: Re: Line Array tricks
Post by: Face on August 08, 2012, 03:44:41 PM
Quote from: richidoo on August 08, 2012, 03:14:44 PM
The CBT array sold by PE uses inexpensive small "full range" drivers designed for laptop computer speakers. They are made by harmon, but I don't know much more about them. PE says they are Dayton part, but they don't list a part number, and apparently not available separately. They sound just OK. The Vifa will be better choice if you can afford.

http://www.parts-express.com/cbt36/ (http://www.parts-express.com/cbt36/)

You mean these?   http://www.parts-express.com/pe/showdetl.cfm?Partnumber=275-010 (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=275-010) 
Title: Re: Line Array tricks
Post by: richidoo on August 08, 2012, 07:14:37 PM
Mike, PE says the CBT uses 3/4 drivers, so probably not the same as those 1/2" But these 1/2" look sweet!
Title: Re: Line Array tricks
Post by: BobM on August 09, 2012, 06:37:16 AM
I haven't personally built a line array, but I have picked up a few tricks on the topic while reading speaker building forums.

- Generally speaking, because there are so many drivers, each one works less hard than normal. They are more efficient. So, in general terms, you probably do not need the absolute best drivers out there, as you would for a 2/3 way or an MTM design.
- Because it is a line array, the upper and lower limits of the drivers determine the top and bottom sweet spots. That is why most line arrays are very tall.
- Line arrays can project a much larger than life sound stage because of their height. That is why you often find that the drivers at the topmost and bottom most are "tapered". This avoids having that 3 foot wide and tall nose on the singer. This is usually done by adjusting how they are wired together (e.g. some in parallel and some in series).
- Some unusual designs actually physically "taper" their drivers by bending the cabinets bend backward, rather than having them stand straight up.
- The interaction between the tweeters and the mid/woofs is critical, and so is their spacing from each other. So you will likely see tweeters recessed in the baffle to avoid unwanted reflections off a faceplate edge and such. So pick your drivers with care to ensure they can all be recessed flat to the baffle.

You are going to be cutting a lot of holes, and to avoid combing effects from a line array the measurements need to be pretty tight. So measure thrice and cut once.

Enjoy,
Bob
Title: Re: Line Array tricks
Post by: S Clark on August 10, 2012, 06:03:03 PM
There is no reason to re-invent the wheel.  Use the Neo 8 tweeter/midrange (as used in the LS6 and LS9 series), and cross it somewhere between 1100 and 1300 Hz.  Why did you decide to use 2" drivers?????  There are so many decent 4-5" drivers that would give you sooooo much better bass response.  How are you planning on taking measurements?  These guys aren't the easiest type of speakers to design well.  One of my students designed a pair, and we both were nearly nuts by the time we gave up, took it Danny Richie, and got him to fix our mistakes.  And we had a very fine Clio measurement system.
Scott
Title: Re: Line Array tricks
Post by: Face on August 11, 2012, 06:36:10 AM
I agree that line arrays are very difficult to measure and design. 

I would suggest talking to Rick Craig, he knows more than most about line arrays.  http://selahaudio.com/id73.html (http://selahaudio.com/id73.html) 
Title: Re: Line Array tricks
Post by: Selah Audio on August 13, 2012, 08:44:30 AM
Quote from: Hornologist on August 08, 2012, 03:10:03 AM
Hi everyone, I am looking for tweeters for a line array. I have 2" drivers for the lower range ( up to 6000 Hz). It is almost impossible to find drivers smaller than 1". Could one of these tricks help ?
Will a waveguide like the http://www.bcspeakers.com/product.php?id=8 (http://www.bcspeakers.com/product.php?id=8) overcome the wavelenght limit, do they form a real array if stacked up directly ?
or could a ribbon tweeter or planar be used ?
Who has some experience in this field ? Thanks a lot Marc   

Do you have measurement equipment?