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Compact Line Array

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Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=41442
Printed Date: 29 March 2024 at 7:26am
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Topic: Compact Line Array
Posted By: PedroQ
Subject: Compact Line Array
Date Posted: 23 July 2010 at 12:01am
Yesterday came the idea to build a small PA for use in small events like karaoke, djs, weddings, etc.
Researched existing models for five minutes, and none had the features I wanted.
The PA must be line array, very small, very light (less than 5 kg per cab), cheap and efficient.

Today I spent another 5 minutes trying to idealize the box, and made a small drawing (in powerpoint because I had no CAD software on the laptop. So the measures are not stringent).

I have not done (yet) tests or measures to see more efficient ways, but I'll probably have to add some vents. The speaker I chose for the mids was Sica 6N2.5PL with 250wrms but probably would sound better with a Beyma 6MI100 of 250wAES. BOTH of 6 inches. And for the HF a Dayton planar tweeter of 80wrms.

What do you think about the idea?

The sketch:

http://img836.imageshack.us/i/compactlinearray.png/">

Uploaded with http://imageshack.us - ImageShack.us





Replies:
Posted By: MarjanM
Date Posted: 23 July 2010 at 1:09am
Are you sure it will be under 5 kilos?

Now that looks good actually but 6 inch cant really do well under 200Hz. Maybe not even that. Also you will need about 10 boxes in a row in order to act as a line array. So try double 6 and a horn. That will do some more damage in a not spl demanding gigs.


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: PedroQ
Date Posted: 23 July 2010 at 1:21am
The  Sica 6" woofer have a freq response of about 120hz to 7khz  (+/-) , so i think it can go 200hz well. about the weight ... the woofer is neodymium with 1,65 kg.


Posted By: PedroQ
Date Posted: 23 July 2010 at 2:09am
I've done some calc's and if i use a vent tunned to 113hz  and reduce the woofer compartment to 2,7 lt I can reach the 120hz without big gain losses.


Posted By: MusicXtra
Date Posted: 23 July 2010 at 4:12am
Have you seen the 18sound 6ND430?
This one is 200 Watt AES and the FS is 63 Hz so it wil work from 60 Hz.


Posted By: PedroQ
Date Posted: 23 July 2010 at 4:23am
I Have seen it, but put it apart because i can't find it any "Portuguese online store" and so i cant know a price for it, but i would contact some stores requesting prices for 6ND430.


Posted By: PedroQ
Date Posted: 23 July 2010 at 4:51am
The 18sound is more appropriated to this box, can go to 87hz in -3db. Sica only can go to 110hz in -3db.     


Posted By: Mircea Bartic
Date Posted: 23 July 2010 at 9:38am
what is the intended crossover point?

-------------
general manager & head designer at nexus-acoustics research
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Ex Nexus_3


Posted By: Tony Wilkes
Date Posted: 23 July 2010 at 10:08am
If you think that any pro 6" driver will do -3db in the 80's when stuck in the air you are deluding yourselves. I don't care what the simm's say, build one and measure it!!!

Tony


Posted By: tomschute
Date Posted: 23 July 2010 at 10:20am
http://www.parts-express.com/pe/pshowdetl.cfm?&DID=7&Partnumber=275-085&ctab=1#Tabs

Great find. Wonder if it will work? I was on a similar project mission that stalled as I was finding the time it was taking to fine tune my own HF line array horn was just too great and put it all to one side.

Maybe this would be an option for a compact system.

Tom


-------------
Out to lunch... stableaudio@hotmail.co.uk
www.stableaudio.co.uk
Speaker Building Services


Posted By: Tony Wilkes
Date Posted: 23 July 2010 at 11:17am
Originally posted by tomschute tomschute wrote:

http://www.parts-express.com/pe/pshowdetl.cfm?&DID=7&Partnumber=275-085&ctab=1#Tabs

Great find. Wonder if it will work? I was on a similar project mission that stalled as I was finding the time it was taking to fine tune my own HF line array horn was just too great and put it all to one side.

Maybe this would be an option for a compact system.

Tom


Tom, not if you want to use best practice. Cross-over way too high, max'm output is way too low.
They may be good in home hi-fi, monitor's etc. but LA's no.

Tony


Posted By: tomschute
Date Posted: 23 July 2010 at 11:35am
Back to the mic and PC then :/

Might grab one and take some measurements out of interest though!


-------------
Out to lunch... stableaudio@hotmail.co.uk
www.stableaudio.co.uk
Speaker Building Services


Posted By: Tony Wilkes
Date Posted: 23 July 2010 at 11:40am
Originally posted by tomschute tomschute wrote:

Back to the mic and PC then :/

Might grab one and take some measurements out of interest though!


Tom, the top end is the only thing that has stopped me from making my own little LA. I could obviously use the BMS jobby but the cost would then rise to a point that I think makes it impractical.

All of the DIY solutions I have seen so far have been too much of a compromise for me.

I have spent quit a bit of time trying to find an inexpensive way around this but so far no joy.

Tony


Posted By: darkmatter
Date Posted: 23 July 2010 at 12:40pm
Originally posted by tomschute tomschute wrote:

http://www.parts-express.com/pe/pshowdetl.cfm?&DID=7&Partnumber=275-085&ctab=1#Tabs

Great find. Wonder if it will work? I was on a similar project mission that stalled as I was finding the time it was taking to fine tune my own HF line array horn was just too great and put it all to one side.

Maybe this would be an option for a compact system.

Tom


I think if you want to run them safely using the full 80 watts you'd want a x-over of 2.5k, which means mid device shouldn't really be any larger than 4.5"/5".

Pedro I think the issue with this design may be a gap between the mid device and Dayton planars if you apply the half wavelength rule? Even if you apply the rule loosely and assume that a 19cm spacing allows a 1800Hz x-over, and are generous with the high pass for the Daytons, you have a gap 1800-2000Hz.


Posted By: MarjanM
Date Posted: 23 July 2010 at 1:26pm
If all of you look ate the boxes that mayor players are offering you can find a lot of examples where they are far from perfect. 

-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Tony Wilkes
Date Posted: 23 July 2010 at 2:35pm
Originally posted by MarjanM MarjanM wrote:

If all of you look ate the boxes that mayor players are offering you can find a lot of examples where they are far from perfect. 


Marjan,  Not going to disagree with you there mate.

For a line array to show some respect to the absolute basics that are required then the job of the HF unit is paramount, IMHO the unit discussed did not get close.

I would like to get my hands on some of the new P.Audio LA wave-guides to give them a go with a good HF driver. Price anyone?

Tony


Posted By: PedroQ
Date Posted: 23 July 2010 at 3:13pm
Originally posted by Mircea Bartic Mircea Bartic wrote:

what is the intended crossover point?

I have think in something like 120 hz for mids, and 3khz for the tweeter.


Posted By: PedroQ
Date Posted: 23 July 2010 at 3:39pm
hmm, this is not to be a perfect cab, is more a way to learn something more and try make things diferent, I know that to be a Line Array there are many rules that i wasn't followed. But, it can have some LA characteristics like the planar waves in the Highs (and the dayton ribbon tweeter can do that without wave guides (ok ok... it is made for hi-fi, but i think i can follow the mid driver pretty well)) and the LA arrangement that is more easy to fly, more good looking and when some cabs are in the array more probabilities i have that it act like an real LA.


Posted By: Saturnus
Date Posted: 23 July 2010 at 6:14pm

The planar speaker in question here not suited for line arrays, nor do I personally thinks it's suited for professional use at all.


If you want a line array suited planar speaker something like http://profesional.beyma.com/ingles/pdf/TPL150.pdf - profesional.beyma.com/ingles/pdf/TPL150.pdf or http://profesional.beyma.com/ingles/pdf/TPL150H.pdf - profesional.beyma.com/ingles/pdf/TPL150H.pdf is far better suited.



Posted By: PedroQ
Date Posted: 23 July 2010 at 6:20pm
and much more expensive too...


Posted By: Louder than loud
Date Posted: 23 July 2010 at 6:34pm
Just copy Q1 :)


Posted By: MarjanM
Date Posted: 23 July 2010 at 7:28pm
Originally posted by PedroQ PedroQ wrote:

hmm, this is not to be a perfect cab, is more a way to learn something more and try make things diferent, I know that to be a Line Array there are many rules that i wasn't followed. But, it can have some LA characteristics like the planar waves in the Highs (and the dayton ribbon tweeter can do that without wave guides (ok ok... it is made for hi-fi, but i think i can follow the mid driver pretty well)) and the LA arrangement that is more easy to fly, more good looking and when some cabs are in the array more probabilities i have that it act like an real LA.



Are you sure about this?


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: PedroQ
Date Posted: 23 July 2010 at 8:05pm
when i said "without wave guides" I refer that not necessary a use of this type of wave guide: 

   

to create planar waves, the ribbon do it naturally. ;)


Posted By: Steve_B
Date Posted: 23 July 2010 at 9:46pm
I did a small design based on the 18sound drive unit ages ago. http://www.burton-manor.co.uk/Audio/Vslapc.htm - Details Here

Depending on the price, this Fountek  http://www.fountek.net/products/neopro5i.pdf - ribbon looks interesting


Posted By: Saul
Date Posted: 23 July 2010 at 9:49pm
Originally posted by MarjanM MarjanM wrote:

Are you sure it will be under 5 kilos?

Now that looks good actually but 6 inch cant really do well under 200Hz. Maybe not even that. Also you will need about 10 boxes in a row in order to act as a line array. So try double 6 and a horn. That will do some more damage in a not spl demanding gigs.

arcline 6 

this will be a scaled down version i reckon 

how many boxes need to be hung for it to become effective as a line array?


Posted By: MarjanM
Date Posted: 23 July 2010 at 10:03pm
What is the vertical dispersion of that ribbon driver again?

Is it 10 degrees?


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: PedroQ
Date Posted: 23 July 2010 at 10:13pm
Originally posted by MarjanM MarjanM wrote:

What is the vertical dispersion of that ribbon driver again?

Is it 10 degrees?

I think it's less.... 


Posted By: PedroQ
Date Posted: 23 July 2010 at 10:15pm
Originally posted by Saul Saul wrote:

Originally posted by MarjanM MarjanM wrote:

Are you sure it will be under 5 kilos?

Now that looks good actually but 6 inch cant really do well under 200Hz. Maybe not even that. Also you will need about 10 boxes in a row in order to act as a line array. So try double 6 and a horn. That will do some more damage in a not spl demanding gigs.

arcline 6 

this will be a scaled down version i reckon 

how many boxes need to be hung for it to become effective as a line array?

more than 6 I suppose  


Posted By: Saturnus
Date Posted: 23 July 2010 at 10:32pm
Originally posted by MarjanM MarjanM wrote:

What is the vertical dispersion of that ribbon driver again?

Is it 10 degrees?


Flat? It's only 5 degrees, that's why it's not suited for a line array. 



Posted By: MarjanM
Date Posted: 23 July 2010 at 10:50pm
Where did you find the dispersion figure? Just because it is flat surface sound source does not mean that it has a narrow vertical dispersion.

As for how many boxes, 2m length of boxes is a minimum to start to act as a line array.


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: rich_gale
Date Posted: 23 July 2010 at 11:42pm
what benefits (other than the look of a line array, which everyone is chumming right now) does this concept give you in the intended task it is designed for?  wont a pair of good quality reflex boxes be more than adequate for small discos and sing alongs?  Line array is for big areas, ideally outdoors? requiring controlled dispersion isnt it?  why for small karoke stuff?

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REFLEX ALL THE WAY.... (however, im playing with horns again...) That ok Mister Valiant? :)


Posted By: kevinmcdonough
Date Posted: 23 July 2010 at 11:55pm
hey

a few months ago I also spent a LONG time looking into this for a system that a friend/client asked me to design.

He started off asking to have a small ground-stack system that would simply look like a line array, with a couple of subs and then a few tops all stacked vertically, as he thought that just having the look of a line array would help just edge things out and tip the balance on a couple of gigs he had narrowly missed.

As i looked into it however i started to think that if I was gonna do it I may as well do it properly, and started playing with designs, and also knocking some ideas about over PM and msn messenger with a couple of other forum members.


I started like you looking at small tops, with single or pairs of 5" or 6" drivers and a single HF driver either a comp on a waveguide or a specific line array driver such as the BMS or Beyma ones, to get essentially half an Arcline 6 or a Coda LA4. (I also emailed to try and get prices for that fountek ribbon but never got a reply).  However the sensitivity of the 5 and 6 inchers, as well as worries about how low they would reach, meant that I would have to build too many cabinets and went over budget.

Then i looked at using pairs of 8" along with two HF units per cab, which brought up the efficiency and lowered the cutoff a good bit, but it meant that I was having trouble crossing over from the 8 to the comp driver while still keeping the correct wavelength spacing etc, meaning i would need special plates to go over the front of the 8's to hive them a front chamber and much smaller slots to exit from, a la Nexo/outline Butterfly/Coda LA8. Again wasn't really workable and would have taken lots of trial and error and testing which wasn't feasible for this small system.

Then I started moving on to 3 way, which i didn't really want to do anyway was supposed to be a simple system, but ignoring that it was the closest I got to a usable design using a single 10", a pair of 5" and a comp on the P Audio waveguide (which exits at nearly 8" tall, much taller than most others and meaning you dont have to spend a fortune on multiple HF units per cab.)

However the complexity of managing a 3 way top (which i tried to avoid as it would be a bit much for the friend/client to use) as well as much more complex build and still relatively inefficient compared to a similar costing DIY horn cab meant that i put it on the back burner.

After LOTS of research I came to the conclusion that you simply couldn't do it cheap, and it was far more cost effective per db of volume to just have normal hornloaded cabs.


What i do think in hindsight may begin to work is an all hornloaded line array cab, like a mini martin, to improve the efficiency and bring it up to scratch.

Something like a ported horn 10" (ported to get the response low enough to cross down to subs), pair of 5" on short horns and one or two comps.  In terms of frequency response I have enough of a handle on Hornresp that I could have a go at it, but the problems is I don't know enough about horns to shape them properly once i had the expansion rates to control the dispersion and get the wide horizontal dispersion needed to match the comp/waveguide and make the cab work. And the hornloading would also push up the size of the cab a fair bit and take you out of the range of super small cabs.

Also, again your pushing the cost up a good bit compared to what you can achieve with something simple like an SMT212, for no real benefit at this level and number of cabs other than looks.



k



Posted By: PedroQ
Date Posted: 24 July 2010 at 5:20am
Originally posted by MarjanM MarjanM wrote:

Where did you find the dispersion figure? Just because it is flat surface sound source does not mean that it has a narrow vertical dispersion.

As for how many boxes, 2m length of boxes is a minimum to start to act as a line array.


So, I can change the design, improve the concept by adding a wave guide to control the dispersion like this:
 

Originally posted by MarjanM MarjanM wrote:

Where did you find the dispersion figure? Just because it is flat surface sound source does not mean that it has a narrow vertical dispersion.

As for how many boxes, 2m length of boxes is a minimum to start to act as a line array.

ok, ok... not 6 boxes, but 10... ;)




Posted By: PedroQ
Date Posted: 24 July 2010 at 5:41am
Originally posted by rich_gale rich_gale wrote:

what benefits (other than the look of a line array, which everyone is chumming right now) does this concept give you in the intended task it is designed for?  wont a pair of good quality reflex boxes be more than adequate for small discos and sing alongs?  Line array is for big areas, ideally outdoors? requiring controlled dispersion isnt it?  why for small karoke stuff?

It still is a very light weight and small cab, the 6" driver is better for vocal's, and in generally reproduce the sound with better quality than a 12" driver for example. for the intended task I dont need high SPL so i can keep the ribbon which is also better sound quality than conventional tweeters our compression drivers, and better dispersion too. Could not be an really line array, but could be a good horizontal speaker that is more easy to fly if I want to use 2 or more boxes per side. So... the question is why not to build it?


Posted By: MarjanM
Date Posted: 24 July 2010 at 10:52am
If you think that it will do the job, do it. But usually it is never easier to fly line array boxes vs stacking trap ones. You have to transport and assemble the flying rig too. That is more time consuming. But you will have a better optical look for sure. Sometimes that is a good selling tool. Have you seen that small DAS line array look a like boxes? They are small and plastic and look good.

-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: rizzardo
Date Posted: 24 July 2010 at 12:23pm
just,

copy the Q1 design: but using a ribbon driver !!!!
Q1 is a very good project: the dispersion is optimum down to 400hz and its a very usable loudspeaker...

I'm a sound engineer and when in the venue I find the Q1 (also stack) I'm very happy Big smile


-------------
Bass is good when they move our trousers


Posted By: PedroQ
Date Posted: 24 July 2010 at 2:16pm
Originally posted by rizzardo rizzardo wrote:

just,

copy the Q1 design: but using a ribbon driver !!!!
Q1 is a very good project: the dispersion is optimum down to 400hz and its a very usable loudspeaker...

I'm a sound engineer and when in the venue I find the Q1 (also stack) I'm very happy Big smile

where can I find it?


Posted By: MarjanM
Date Posted: 24 July 2010 at 3:40pm
Stop talking nonsenses! You can copy the look but how on earth you can cross the v slotted 10 units drives at 3000Hz? That will sound just terrible.

BTW who will make you the rigging pieces? Have any idea how much that will cost?

So no cheap at the end. I can do it for maybe 600 pound per box but not less anyway.


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713



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