# Line Array thoughts.



## mayhem13

Man this is really murky water on this subject. The thought of a line array with inexpensive surplus drivers has really got my attention. I'm thinking 8 4" Peerless Mid-bass with 8 1" titanium domes (only 2" overall diameter) in close proximity to each other on convex open baffle with stereo subs of 2 10's each. I can purchase all the drivers for a stereo pair for under $500.00. All the negatives on the subject of line arrays from 'audiophiles' really confuses especially when i look at McIntosh's line of speakers. Any thoughts ??


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## BoomieMCT

mayhem13 said:


> Any thoughts ??


Yes . . . do it and then write about it!


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## mayhem13

I'm sure you have more to add !


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## BoomieMCT

mayhem13 said:


> I'm sure you have more to add !


Sure. Read Dr. Griffin's white paper on the subject.

Are you planning on crossing this actively or passively?


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## drf

mayhem13 said:


> All the negatives on the subject of line arrays from 'audiophiles' really confuses especially when i look at McIntosh's line of speakers. Any thoughts ??


most audiophiles are just people who think that unless you have spent as much as they have, or your cables have the same logo on them then you are listening to rubbish.


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## JCD

I think it's a great idea..




























Not done yet with mine, but it seems like a fairly easy way to go and there is something about a huge line of drivers that's intrinsically sexy to me.

JCD


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## mayhem13

I'm thinking passive if possible.


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## BrianAbington

http://www.mcintoshlabs.com/products/mcintosh-xrt2k-reference-loudspeaker.asp

these are insane.


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## mayhem13

I'm in love with the looks of these. They gotta sound amazing !


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## Bill Fitzmaurice

Ignore the pundits. Arrays are only a problem when too high for the distance to the listeners; I find that a minimum 3:1 distance versus array height eliminates pathway differential and lobed response issues. I don't see any advantage to an open baffle, though.


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## jeffreybehr

I LOVE LOVE LOVE linearrays, and I've built several the last few years. Here's the current version...








These are built with Sonic Craft 6-1/2" B/MR drivers, and they sound EXCELLENT if I say so myself*. These drivers are discontinued and soon will be unavailable, but probably the best thing about them, other than their basic very high sound quality, is that they're only $10 each in 24s. (I love 'em so much I just bought an extra carton of 24.) I used Parts Express's inexpensive Dayton mag.-planar tweeters, and while they sound good, the quality of the treble is NOT as high as that of the output of the B/MR drivers.

My systems are open-baffle, and they sound MUCH more-spacious than if they were sealed, but that's a personal preference. One thing I know--I'm never going back to a nonopen-baffle speaker system. 

I think you need to do one of two things for tweeters--use one point-source** tweeter (and I'd use a ribbon tweeter by probably Aurum Cantus) or use a line of tweeters that are about as tall as your line of B/MR drivers. I think you'll hear lobing with 1"-dome tweeters; I know I and my friends did using 1" domes that were 2-1/2" center-to-center.

I'll soon be building finished versions with TWELVE B/MR drivers and (I hope) electrostatic tweeters by Roger Modjeski (Music Reference). These will be 2-ways, as are my current versions now since I've stolen those 12" woofers to use in my JB/JG-SuperSubs.









If Modjeski's tweeters aren't finished when I'm ready for them, probably I'll use some inexpensive single dome tweeter temporarily.

I'm actively filtering and EQing these with a dbx-brand DriveRackPA; I'm using (relatively) inexpensive Music Reference EM7 Single-Ended triode amps to drive them. http://www.ramlabs-musicreference.com/EM7.html With a sensitivity of c. 100dB, they require little power to fill the room.
.


* Others, too, say so, and if you'll e-mail me at jeffreybehr(at)cox(dot)net, I'll forward comments from a couple friends.
** Understand that the MR/treble balance from such a hybrid system will be correct at only one distance.


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## HionHiFi

jeffreybehr, 
Nice Array's. I too have been interested in the design ever since reading Dr.Griffin's paper. It is absolutely essential reading for anyone attempting such a design. 

How does the open baffle design affect the sound of the system you posted above? I like the idea of having an open baffle, because it makes cabinet building EASY, rather easier. This is especially appealing since I do not possess many tools in my workshop (jigsaw, circular saw, multi tool with plunge router attachment). 

Have you experimented with other tweeters, cone, or dome? Parts Express has a nice little Dayton ND20FB-4 Rear-Mount 3/4" Neodymium design that I've been eye balling lately. It mounts from the back, which would make it easy to mount. It's only $4. PE#: 275-035.


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## JCD

I have no way to back this up, but I think Dr. Griffin's paper has lost favor lately. For example, I think the tapered power handling isn't in vogue as much any more.

I think the more modern approach is the work done by Roger Russell.

JCD


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## Bill Fitzmaurice

JCD said:


> I have no way to back this up, but I think Dr. Griffin's paper has lost favor lately. For example, I think the tapered power handling isn't in vogue as much any more.
> 
> I think the more modern approach is the work done by Roger Russell.
> 
> JCD


Griffin approaches LAs from the theoretical direction, Russell from the practical. Both are a bit dogmatic, but that's to be expected. Anyone who doesn't firmly believe in their position probably doesn't have a position worth believing in.


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## HionHiFi

Ok, now after soaking up Roger's information, theory, and practical design, I'm re-looking at building a Line Arrary. 

Where can I find more info on Roger's design, ie. wiring of the drivers, and Eq specifics about where to boost to entend down to 20hz, and out past 18khz? 

I'd probably start with building a low cost design first, using something like a Behringer DEQ-24/96 EQ, or something that would do the job. Any thoughts?


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## Bill Fitzmaurice

intelonetwo said:


> Where can I find more info on Roger's design, ie. wiring of the drivers, and Eq specifics about where to boost to entend down to 20hz, and out past 18khz?
> Any thoughts?


That's where Roger and I part company. Whether it's a line or point source dispersion and response issues still dictate that no less than a 2 way, and preferably a 3 way system is necessary to run the full audio bandwidth. I believe you can get what you're looking for via the link above, though.


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## JCD

Bill Fitzmaurice said:


> That's where Roger and I part company. Whether it's a line or point source dispersion and response issues still dictate that no less than a 2 way, and preferably a 3 way system is necessary to run the full audio bandwidth. I believe you can get what you're looking for via the link above, though.


I think going with a two or three way also makes sense. From my understanding, he's eq'ing the low end a LOT. The reason why it isn't distorted beyond all get out is because he has so many drivers. The other thing that should be noted is the drivers he's using -- I can't remember what they are off the top of my head, but they weren't the $8/driver type I used. :bigsmile:

In the end, my plan was to eq a little bit to extend my line array down to work with a powered sub as well as using a horn loaded tweeter that's SUPER efficient to handle the duties from maybe 8k and above.

Oh, and I wired my drivers so that they all receive the same amount of power, but with the combination of parrallell and series wiring, I was able to get a nominal 6ohm system.

JCD


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## jeffreybehr

"jeffreybehr, nice arrays." *TY. I have lots of hours and $ invested.*

"I too have been interested in the design ever since reading Dr.Griffin's paper. It is absolutely essential reading for anyone attempting such a design." *Wasn't essential for me; I've never read it. But...then...maybe some of youz are thinking 'ya, it looks like it'?!?!?!?!*

"How does the open baffle design affect the sound of the system you posted above?" *As I wrote above, OB designs are much more spacious sounding than closed designs, and spaciousness is a sonic requirement of mine. Also, OB designs lack bass due to Wrap-Around Cancellation. WAC is reduced by the use of wings separating the front and back, the longer the better*, and can be offset by electronic equalization, either passive or active. Of course one must have enough amplifier power and driver power handling to do much of that, and here multiple drivers help immensely.*

"I like the idea of having an open baffle, because it makes cabinet building...easier. This is especially appealing since I do not possess many tools in my workshop (jigsaw, circular saw, multi tool with plunge router attachment)." *You have more than I!*

"Have you experimented with other tweeters, cone, or dome? Parts Express has a nice little Dayton ND20FB-4 Rear-Mount 3/4" Neodymium design that I've been eye balling lately. It mounts from the back, which would make it easy to mount. It's only $4. PE#: 275-035." *I've tried 1" soft-dome tweeters from old Kindel PLS-As...








They sound plenty OK but not up to the quality of the JG65 drivers. I've also listened to Aurum Cantus G2 ribbon tweeters; they sound EXCELLENT but are too expensive for me in enough quantity for a linesource. I suspect those inexpensive Daytons would sound OK, but if you're going for inexpensive AND a linearray, I'd use a batch of these...








...VERY inexpensive tweeters from Apex. http://www.apexjr.com/speakerstuff.html At $1 each, one can afford to toss them if they don't sound good enough. *


* *Of course large wings have their own perhaps-big problem, namely panel resonances. Mine were QUITE audible, and I spent weeks adding material and bracing to sort-of eliminate their resonances. Here's a clue.








Had I known then what I know now, I'd have used 1" PLUS 3/4" MDF for them. The new systems will have 1-3/4"-thick wings, smaller than the current systems', and which will require more electronic equalization. I use an active filter, a dbx DriveRackPA, in my triamped system. 

Do yourself a favor--call Sonic Craft...800/689-9800...and buy a carton of the JG65 drivers before they're all gone--and they will be SOON. You'll be happy you did. I again offer to send you the e-mail of my 2 friends' comments on the sounds of my prototype systems. E-mail me at jeffreybehr(at)cox(dot)net and I'll forward it.*


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## Bill Fitzmaurice

jeffreybehr said:


> Of course large wings have their own perhaps-big problem, namely panel resonances. Mine were QUITE audible, and I spent weeks adding material and bracing to sort-of eliminate their resonances.


That's one of the reasons I don"t care much for OBs, they can turn into a never ending project. I put these TL arrays on my walls and never had a reason to touch them again.


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## rickp

I love line arrays also and, I am planing on building 3 sets for my new HT. I don't quite know what to do with the center channel yet. I have studied Griffins paper as well as Russels info. I think between the both of them I have gathered enough info to be dangerous:coocoo: I will be using an active crossover and a 4-18" IB sub.

Best of luck, keep us posted. Rick.


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## mgboy

I've always wanted to try line arrays but due to the price I've never been able to, but when people talk about building them I get a smile on my face because they seem so interesting. I say go for it, for both out sakes. 

I might try a line array with the buyout HiVi drivers on PE. =P At 5 bucks a pop, what's not to like? Other than muddy bass.. lol.


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## rickp

Mike, I figured I could spend 10$ per speaker and hopfully get something quite a bit better, we shall see. I just purchased 3 cases of the Sonic Craft speakers and they look good :T Now I need to find some complimenting tweeters, any ideas? The next decision I need to make is Open Baffle, Sealed or Vented cabinets. Any more ideas? I will also need some help with cabinet design.

Thanks, Rick.


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## jeffreybehr

rickp said:


> Mike, I figured I could spend 10$ per speaker and hopfully get something quite a bit better, we shall see. I just purchased 3 cases of the Sonic Craft speakers and they look good :T Now I need to find some complimenting tweeters, any ideas? The next decision I need to make is Open Baffle, Sealed or Vented cabinets. Any more ideas? I will also need some help with cabinet design.
> 
> Thanks, Rick.


1. Rick, you will NOT be sorry your bought those SonicCraft drivers; EVERYONE who has heard my systems LOVES their sound, even as complex as it is.
2. I too am investigating tweeters, again. One problem with dome tweeters is some Venetian-Blind Effect, AKA lobing, at the highest audible frequencies. One-inch-dome tweeters need neodymium magnets so that the tweeters are small enough to be spaced close enough to have very little VBE. The smallest, at 2-1/8" square, 1"-dome tweeters I can find so far are these HiVi TN25s, only c. $8 each in quantities from Parts Express... http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=297-408 ...









Another 2-1/8"-square tweeter I'm considering is the Morel MDT-12, but it's lots more expensive at c. $29 in quantities.
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=277-060









BTW, I believe most of us would think a $29 tweeter to be NOT expensive, but when one is using 24 (for 8 Bass/MR drivers) or 26 (for 9) or 30 (for 10) PER CHANNEL, $29 each gets quite expensive.

Because insetting them into a frontplate would be much-more time consuming than insetting a square tweeter, I'm unlikey to choose the Tand Band 25-302SH...
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-804

...or the Vifa BC25SC55-04 from Madisound...
http://www.madisound.com/catalog/product_info.php?cPath=45_229_270_324&products_id=8355
...even tho both qualify on height.

3. On cabinet design:
A. If you have the space in your room to place the fronts of the speakers at least, say, 3' away from all walls AND you enjoy the spaciousness that OBs have, use open-baffle. Unless you actively EQ them, probably they'll need some passive EQing, usually called baffle-step compensation, to 'recover' the lower MR and bass frequencies lost to WAC. Of course, that consumes sensitivity, but you'll have that to burn by using multiple drivers. (My 8-driver systems have a [email protected] sensitivity of c. 100dB.) As I indicated in one of my e-mails to you, I have rough plans for a new OB LA design that you're welcome to.
B. If you don't have that much space or if you prefer the more immediate, forward sound of front-only-firing speakers, then build closed cabinets. Jeffrey Glowacki has told me several times that the correct cabinet volume for the JG65s is one cubicfoot per driver, but because I never wanted to enclose them, I don't remember if that's a sealed or a ported system. You might ask at [email protected] .

One more thing, everyone--Sonic Craft is now down to one full and one partial cartons of these excellent B/MR drivers, so if you've been considering them but just haven't gotten around to ordering them, do it soon or they'll be gone.


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## JCD

I went a different route.. I choose one super efficient tweeter, a "fostex horn super tweeter".

Not ideal, but it avoids the lobing issue and, because it's as efficient as it is, it keeps up with the multiple drivers and their increased acoustic output due to the speaker coupling, and it doesn't break the bank.

Just another way to skin the cat.

JCD


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## mayhem13

There's some nice small 1" domes on the bottom of this page
http://home.comcast.net/~jhidley/


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## Bill Fitzmaurice

JCD said:


> I went a different route.. I choose one super efficient tweeter, a "fostex horn super tweeter".
> 
> Not ideal, but it avoids the lobing issue and, because it's as efficient as it is, it keeps up with the multiple drivers and their increased acoustic output due to the speaker coupling, and it doesn't break the bank.
> 
> Just another way to skin the cat.
> 
> JCD


I built mine with $1.00 'NSB' midbasses and 29 cent Onkyo 3/8" domes. One of the major advantages to an array is that one does not need to use expensive drivers. You can, but it probably won't sound better, it will just cost more. As for the lobing issue, that's a major concern if your listening position is a few feet out. Otherwise, not so much.


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## jeffreybehr

JCD, a single (point-source) tweeter is certainly usable with LS B/MR, but some of us would not like the treble balance that changes with distance. I'm glad it's working for you.




mayhem13 said:


> There's some nice small 1" domes on the bottom of this page
> http://home.comcast.net/~jhidley/


Altho my hi-frequency hearing is poor--with a canyon starting c. 2KHz and ending c. 8KHz--I seem to be sensitive to treble _quality_, and I've yet to meet a metal-dome tweeter I love. That's why I'm shopping for soft-dome tweeters.


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## mayhem13

Personally, i'd do a high efficiency, hi power handling single dome mounted in a waveguide at ear height-possibly Morel MDT37. There are some Vifa mids i think BS14wg's on sale at madisound for 10 bucks. FR looks pretty good for a 1.7khz xover point.


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## lcrooks

rickp said:


> I love line arrays also and, I am planing on building 3 sets for my new HT. I don't quite know what to do with the center channel yet. I have studied Griffins paper as well as Russels info. I think between the both of them I have gathered enough info to be dangerous:coocoo: I will be using an active crossover and a 4-18" IB sub.
> 
> Best of luck, keep us posted. Rick.


First post, nice forum!

Here's my center. Dispersion is excellent. It's built with the $1 nsb's (now all gone) and .25 closeout onkyo tweeters, as are my mains. I love the sound of line arrays for ht. 









Here's a construction pic so you can see what's underneath.


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## drumdude

*line array question*



Bill Fitzmaurice said:


> Ignore the pundits. Arrays are only a problem when too high for the distance to the listeners; I find that a minimum 3:1 distance versus array height eliminates pathway differential and lobed response issues. I don't see any advantage to an open baffle, though.


3:1? Do you mean to listen to a 4' array you want to be at least 12' away, 18 feet back from a 6' array?


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## Bill Fitzmaurice

*Re: line array question*



drumdude said:


> 3:1? Do you mean to listen to a 4' array you want to be at least 12' away, 18 feet back from a 6' array?


Ideally, yes, though that's an oversimplifcation, as the bandwidth of the array, and thus the wavelengths produced, are just as pertinent. Overcoming this is why you'll often see an array of midbasses with a single tweeter, though IMO that takes things too far in the opposite direction. But this does point out an inherent shortcoming of 1 way or even 2 way arrays. The higher in frequency you go the less height is required of it, and vis-versa. While a floor to ceiling hieght is fine for a woofer array, half that size for the mids and half that again for the tweeters is more appropriate for average size rooms.


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## shawnb

Fitzmaurice's TLAH.These are Vifa's from Madisound clearance.$460 total to finish I love line array's now


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## jeffreybehr

Pic didn't work.


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## shawnb

Sorry for some reason I can't get it to work.There in new guy system pics in diy speaker section


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## Mike P.

Pic Fixed.


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## rickp

Your LA's look great! What tweeters did you use?


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## shawnb

they are piezo model 1016.I know.I know PIEZO!when you listen to 1 its not very nice but coupled together its a different world.they don't get pushed hard and are not harsh at all.Now i do eq the top end down abit but I was amazed at about $1 a tweeter.


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## BrianAbington

I'm just begining to learn about designing crossovers...is there a huge difference in designing crossovers for line arrays vs. a standard two way speaker?

How would you build a line array x/o for a 3 way design?


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## shawnb

I didn't use crossover in mine.The 5.25's rolloff was right where the piezo's would start.Worked out very close.But I use programs from computer.3 way isn't all that different from 2way just more parts.Determining where to crossover is the key.My case has been alot of experimenting.With a line array its figuring out the attenuation circuit that can be a pain in the butt.I bought cheap plans from Bill Fitzmaurice for mine they are called TLAH's and it comes with all the info you need(with pics).Including crossover design.Worth the $14.95 investment.


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## Bill Fitzmaurice

SQCherokee said:


> I'm just begining to learn about designing crossovers...is there a huge difference in designing crossovers for line arrays vs. a standard two way speaker?


No. 



> How would you build a line array x/o for a 3 way design?


The same as for a point source. Decide on the corner frequencies and calculate the component values.


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## BrianAbington

Bill Fitzmaurice said:


> The same as for a point source. Decide on the corner frequencies and calculate the component values.


Could you please clarify that for me? Corner frequences and component values are new terms to me.


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## Bill Fitzmaurice

> Corner frequences and component values are new terms to me


That being the case, I would recommend going with a tested design. Finding the right frequency to cross from one set of drivers to the next is best done by measuring the off-axis response of the finished cab.


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