Line array ?

flatheadmurre · 2011-09-07 11:01 pm

I got a box of 3" fullrange speakers and now i´m a little curious about how to best use them.

A line array has always been out of range money wise.

The drivers are monacor SPX-30M.

Is it a good idea tro try them out in a fullrange line array ?

Someone with experience in line arrays can perhaps give some advice.

flatheadmurre · 2011-09-08 6:59 am

So off to the lumberyard for some chipboard.

Ceilingheight says 24 drivers no more.

Some kind of open baffle contraption coming up.

Don´t really know how to sim the effekt of close together drivers interfering will be about 4" cc.

Anyone more experienced please feel free to join.

jerryo · 2011-09-08 8:27 am

Hi,
have you searched for Line Arrays on the forum yet? There are a number of threads on the subject which will answer alot of questions that you might think of. It's well worth the effort of searching before getting down to specific questions.

Cheers

oLjud · 2011-09-08 8:33 am

I'm also thinking about building me a line array, but with Faital Pro 4" and not as many drivers (for starter). But I considering an sealed enclosure with a EQ-boost for the bottom-end, instead of OB since my space in the apartment are very limited.

I think Hornresp or lspCAD may be able to simulate a line array, not sure.

graaf · 2011-09-08 8:36 am

flatheadmurre said:
I got a box of 3" fullrange speakers and now i´m a little curious about how to best use them.

A line array has always been out of range money wise.

The drivers are monacor SPX-30M.

Is it a good idea tro try them out in a fullrange line array ?

Someone with experience in line arrays can perhaps give some advice.

see:
http://www.diyaudio.com/forums/full-range/164797-200-x-2-drivers-what-do-8.html#post2160121
and:
http://www.diyaudio.com/forums/full-range/164797-200-x-2-drivers-what-do-9.html#post2163298

You do not need 100 drivers, the concept can be scaled down, see also:
http://www.diyaudio.com/forums/full-range/164797-200-x-2-drivers-what-do-5.html#post2148306

Boscoe · 2011-09-08 9:00 am

Could you not just winisd to model the array? Otherwise if you wanted to see how the high end is affected due to the distance of the drivers away from each other I think akabak may only be you friend there.

graaf · 2011-09-08 9:13 am

Boscoe said:
Could you not just winisd to model the array? Otherwise if you wanted to see how the high end is affected due to the distance of the drivers away from each other I think akabak may only be you friend there.

below is a simulation fo 10x10 of 2-inchers
looks like a real laser speaker 😀 the sweet spot is just around 25 cm @300cm distance
effectivity of such a array speaker is very high so there is plenty of headroom for in room equalization of the highs and bass

graaf · 2011-09-08 9:17 am

oublie · 2011-09-08 9:53 am

start by reading this white paper

http://www.audioroundtable.com/misc/nflawp.pdf

what distance will you be sitting from the speakers?
What height is your room?
What will you be using for bass and tweeters?
How may drivers have you got?

I've attached a graph of a line of 12 monacors wired 4parallel 3 series measured on axis at 2meters with 2.83v notice where the highs start to roll off around 1khz. Also note that the are usable down to about 100-150hz

graaf · 2011-09-08 9:59 am

oublie said:
start by reading this white paper

http://www.audioroundtable.com/misc/nflawp.pdf

do not read this white paper, most of theorical problems it discusses are not practical problems

You can overcome the real practical problems with a bit of equalization
check out these:
Advantages* of the* IDS Technology
Parts Express DIY Project

oublie said:
I've attached a graph of a line of 12 monacors wired 4parallel 3 series measured on axis at 2meters with 2.83v notice where the highs start to roll off around 1khz. Also note that the are usable down to about 100-150hz

yeah, basic assumption in case of such an array is that freq equalization is mandatory

oublie · 2011-09-08 10:08 am

graaf said:
do not read this white paper, most of theorical problems it discusses are not practical problems

I found that this paper give a very good basis for starting with line arrays the op has to begin somewhere. Dont you think telling the op not to read the paper is a bit strong?

graaf said:
You can overcome the real practical problems with a bit of equalization
check out these:
Advantages* of the* IDS Technology
Parts Express DIY Project

yeah, basic assumption in case of such an array is that freq equalization is mandatory

Its a given that equalisation is used but my model is of the raw driver.

maybe this site may be of some use to the op.

The Murphy Corner-Line-Array Home Page

graaf · 2011-09-08 10:15 am

oublie said:
I found that this paper give a very good basis for starting with line arrays the op has to begin somewhere. Dont you think telling the op not to read the paper is a bit strong?

no I don't - I believe that this paper can be seriously misleading, one might invest a lot of work/money/time in fighting problems that are real only on paper

oublie said:
Its a given that equalisation is used but my model is of the raw driver.

yeah, I know, my point exactly - such a raw array response ought not discourage anyone from trying it as we assume equalization

oublie said:
maybe this site may be of some use to the op.

The Murphy Corner-Line-Array Home Page

yeah, another nice idea 🙂

flatheadmurre · 2011-09-08 12:51 pm

I´m very impressed by all you good people trying to help.

I have to read up on line arrays.

My first idea was 24 elements floor to ceiling one row each side.

Think i will build some kind of OB measurement contraption and play the drivers for a while to see what they will do.

For tweeters i really want none but measurement will probably say something else.

I´ll spend the evening reading suggested material.

Jim Griffin · 2011-09-08 2:57 pm

graaf seems to think that my 'Near Field Line Array White Paper' is not useful and deals with only theoretical issues. On the other hand dozens of builders have personally contacted me and offered praise on how they used the NFLAWP to help them on their line array projects. I also see hundreds of references to this paper across the various DIY speaker forums and even in Floyd Toole's "Sound Reproduction" book. I suspect that my paper is more useful than any assistance that graaf has offered in his more than 1300 posts on DIYAudio.

Jim Griffin

flatheadmurre · 2011-09-08 3:11 pm

Jim i haven´t had time to read your paper but i will.

I´ve built a few speakers before, and simmed 24 elements in BASTA.

I´m not so sure it´s the right program for this application but it´s a start.

I´ll take good advice from all of you so please don´t start firing on each other!!

You all seem more experienced in this line array buisness so let´s cooperate for a brilliant build.

I was thinking 3 sided OB for measurement and driver runin if you think a closed box is better please shout before the powertools hit the board 🙂

Jim Griffin · 2011-09-08 4:07 pm

flatheadmurre said:
Jim i haven´t had time to read your paper but i will.

I´ve built a few speakers before, and simmed 24 elements in BASTA.

I´m not so sure it´s the right program for this application but it´s a start.

I´ll take good advice from all of you so please don´t start firing on each other!!

You all seem more experienced in this line array buisness so let´s cooperate for a brilliant build.

I was thinking 3 sided OB for measurement and driver runin if you think a closed box is better please shout before the powertools hit the board 🙂

While I'm not a big fan of a line array realized with only small full range drivers, you have in this thread links to designs from Roger Russell, Darren Kuzma, and John Murphy. All of these designs use equalization to boost the low end and high end of the frequency band. These are all simple to realize and can sound OK when equalized. If you choose to go with an open baffle approach, you will need a larger baffle, more EQ, and more space within your listening room. Likely a sealed box will be easier to build and more adaptable to EQ. Good luck on your project.

Jim

planet10 · 2011-09-08 4:24 pm

You might find ideas from this design useful;

--dead link--

We are cuttrntly working on a 20 driver fountek FR88ex line based on stuff in the above.

dave

sreten · 2011-09-08 4:27 pm

http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Pipeline_copy.pdf

Hi, might be worth a read, rgds, sreten.

bjorno · 2011-09-08 6:06 pm

flatheadmurre said:
..I was thinking 3 sided OB.. 🙂

flatheadmurre · 2011-09-08 6:49 pm

Ok, eyes bleeding from reading constantly since coming home from work.

I´ll try to sneak out early tomorrow and start building testboxes.

Have to repair my measurement amp that was attacked by the kids to.

Wife mumbling something about attending party,have to catch the speakerflu 😀.

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