DIY "Line Array Test" Boxes

[IWalker]

Pictures are coming later...but they're nothing special...it's basically a mini-monitor sized box with an Usher 8945P Woofer and a BG Neo3-PDR next to it...a small slice of 7'+ line arrays I want to eventually build. FINALLY got them assembled and attached to my active crossover.

How do they sound? MUCH better than I expected! Enough so that the "test" has been deemed a preliminary success, and after I get some other opinions...I'll likely move forward with building the whole arrays.

More later...

 

[jtwrace]

Pictures are coming later...but they're nothing special...it's basically a mini-monitor sized box with an Usher 8945P Woofer and a BG Neo3-PDR next to it...a small slice of 7'+ line arrays I want to eventually build. FINALLY got them assembled and attached to my active crossover.

How do they sound? MUCH better than I expected! Enough so that the "test" has been deemed a preliminary success, and after I get some other opinions...I'll likely move forward with building the whole arrays.

More later...

Your freekin' killing me.

 

[Brad225]

"Your freekin' killing me." JTW those were my exact thoughts before I saw your post.

Come on Iwalker we need picks here. That is just mean to have text only.

 

[IWalker]

Aww, they're just ugly test boxes. Pictures you shall have, though. I'll take some now.

 

[IWalker]

Still have to play around with the crossover point/slope and some various EQ options...but even "out of the box" with levels matched between the drivers, the sound is pretty great. The planar tweeter has great detail retrieval, and the critical Q box isn't the least bit "boomy" which has been my complaint with most box speakers... Too much "love" in these for me to be unbiased though...I'll wait for JTWrace's impressions...though these aren't supposed to be an end product...just the driver selection test for the line arrays... Very happy with the driver choices though.

 

[Brad225]

Thanks for the pic. It gives us an idea where you are headed. How many drivers will you have in the 7' array?

Keep us up to date.

 

[IWalker]

I'm thinking about 6 woofers per side, and probably around 12 tweeters. It'll be a 4 ft array, but the box will be 7ft tall. My room has horrible acoustics...so the presumably flat response from the speakers themselves then get all goofy in room. I've eq'ed them pretty flat, but want to listen to get an idea of the type of effect that has on the sound.

 

[Dreamer]

Sounds like they are going to look sort of like the old Infinity References. Man, those were some beautiful-sounding wood-covered refrigerators...

I first heard th Infinity Ref's at a Myer Emco in northern VA back in the early 1990's. They were being driven by an all-Audio Research front end, complete with some of the biggest tube monoblocks I'd ever seen at the time. There were enough KT-88s in those beasts to raise the room temperature by about 15 degrees over the course of a day. I tink they had to get special clearance from VEPCO to demo that setup, due to the power draw on the grid. Inefficient as heck, but they sounded super-schweet!

Good luck with you rexperiment. Looks promising...

--Richard

 

[IWalker]

Yeah, I'm definitely not claiming to be covering any new ground here If/when I get them completed (at least 6 months-1 year out, based on expenses, I'm figuring) I'll try to host a small gtg...see what you think. Hopefully I'll be in a house by then, so impressive test demos won't annoy the hell out my neighbors, as I'm sure they do in my apartment. Can't wait to see what they think when I buy the driver to complete this 2nd sub!

 

[JonFo]

Iwalker, 12 BG's plus 6 woofers whould throw a nice, deep soundfield.

What low-end FR goal are you shooting for? i.e. flat to 60hz?

And the big question: BG's, not ML's for the highs? Heresy

Got any visio or 3D renderings of what you are planning?

 

[IWalker]

That's what I'm hoping! Nice big soundfield, high sensitivity, high max output, and very low distortion at normal output.

(I don't like listening very loud, but like the ability to have realistic peaks...and the lower distortion that comes from playing well within a driver's capability)

I'm going to be crossing over to 2 12" servo subs at around 80Hz, though I could potentially look at crossing them higher...it's not particularly likely. I'll eventually upgrade the 2 12"s to 4 of them, or an IB if I get the space to accomodate it.

Yeah...I was torn between my midrange/tweeter options. My thoughts...and they may be misguided, were that a line of neo3s would be able to play to ear shattering levels with very low distortion, while MLs, or other "full range" stats, because they're designed to reproduce a fuller range, don't have nearly the sensitivity/power handling combination that the BG line will. I may eventually try a SET amp on the tweeters...just to see what the buzz is about.

No renderings...except in my mind. The best I can do is a description.

7' tall, with 6 7" woofers spaced 1-2" apart starting from the top (extending down 4' or so...maybe more depending on spacing) The tweeter line will be as close to the woofers as I can get them...and will be spaced as close to each other as they can get as well. These will extend the same length or slightly longer than the woofer line. Active crossover...somewhere between 1000-2000 Hz, slope negotiable. I'll be trying to make these curved back, and I'll stuff them with polyfill, etc. Double thick baffle... .75 ft^3 sealed enclosure per woofer.

Then, if I'm as happy with them as I hope/expect...I'll veneer them with something somewhat exotic...maybe a carpathian burl or something of the sort.

What are your thoughts about keeping each cabinet seperate, vs keeping the internal volume open?

 

[jtwrace]

IWalker

let's do some drawings...

 

[IWalker]

Sounds good...I'll take the measurements necessary.

 

[JonFo]

…
I'm going to be crossing over to 2 12" servo subs at around 80Hz, though I could potentially look at crossing them higher...it's not particularly likely. I'll eventually upgrade the 2 12"s to 4 of them, or an IB if I get the space to accomodate it.

Definitely consider IB if you have the space, it’s nothing short of amazing what a good IB can do. Although one needs to plan very, very carefully. You get one shot at the hole cutting thing

…
Yeah...I was torn between my midrange/tweeter options. My thoughts...and they may be misguided, were that a line of neo3s would be able to play to ear shattering levels with very low distortion, while MLs, or other "full range" stats, because they're designed to reproduce a fuller range, don't have nearly the sensitivity/power handling combination that the BG line will. I may eventually try a SET amp on the tweeters...just to see what the buzz is about.

Hum, you need to come to my meet in September. My rig is under 1% total distortion to 105db and hits 115 with ease (I’ve not done a distortion measurement at that level as it takes too long to get the reading, and 115 dB is bloody loud).

The myth that ML’s can’t play loud is just that, a myth. Maybe it takes removing the passive crossovers from the signal path to allow them to go full-song, but I assure you, high-SPL in the >2Khz range is not a problem (with the right high-current amp that is).
What they fail miserably at (relative term, no flames ) is the mid-bass. Their dipole nature plus panel resonances are likely culprits here.
The fix is a big line of mid-bass drivers, as you are planning.

I’m also intrigued by what’s being planned for the CLX. Sounds like they went with an ESL mid-bass dedicated panel with a rear-wave guide to manage the cancelation. It would definetely be preferable to do an ESL line array for mid-bass if one can get:

• The excursion high enough to handle 105db at 60Hz.
• Manage the rear wave so low-frequency cancelation is mitigated
• At least 5’ of vertical height.

…
What are your thoughts about keeping each cabinet seperate, vs keeping the internal volume open?

When you say separate, do you mean woofer to woofer or woofer array to tweets?

Definitely keep tweets separated, but that’s obvious.
Some say individual woofer isolation is preferable, and on the surface, I’d agree, but reading on all the LA’s out there, it does not seem to make a substantial difference.

Looking forward to the drawings

 

[IWalker]

Jon, always appreciate your thoughts/inputs! Thanks!

IB is far from an option at this point. Doubtful that it'll be an option in my next place - I'm pretty much sold on the merits, though. I would definitely give it a try if I had a space that worked. I'm very happy with the quality (and pricing) of my sub right now...so will end up just building 1-3 more (have the 1 box built...will have to build 2 more if I want 4...I wouldn't go for more than 2 in my current space (read:apartment)

Your comments on the MLs having great distortion/power handling even at thundering SPLs is very encouraging. I think the removal of the passive X-over is probably an important step.


I'm hopefully VERY close to auditioning some Final Sound 400is, which I think would mate very well with a midbass array...so if they are as good as hoped, I might forgo the planar tweeter line (use them in another design later on) and just go with a closed back (critical Q) midbass array of 8945Ps. I should certainly give the daytons a chance in a closed back config...but in their current dipole configuration, I've come to the conclusion that they're likely underdamped. (I get under/overdamped backwards...) For pure bass performance below 500Hz or so, there shouldn't be a huge difference between the Daytons and the Ushers....but I'm definitely enjoying the sound from the Ushers in their test box much more than I do the Dayton line. Need to do more experimentation...

On the tweeter front...it might be something about being used to having a huge radiating surface in the treble/midrange (which a line might fix) but I'm not nearly as enthusiastic about the BG tweeters as I am about the usher woofers. Love the woofers to bits...BG I'm considering alternatives too...Also, using something else would allow me to keep the crossover out of the midrange, which I'd prefer.

Question for you...wouldn't an IB also be under/overdamped (whichever one results from having too little backpressure) causing it to have less than ideal response? I was under the impression that a critical Q box was ideal for transient response. I just don't know that much about it though.

Yeah, I was referring to keeping each woofer enclosure seperate from each other. The tweeters have a back-cup, so it probably wouldn't matter if I put them in the same enclosure...but that's a different question.

As I see it - Having seperate enclosures/compartments for each woofer

Pros - ??? More rigidity?

Cons, - can't share internal volume (ie, have a 7ft box, with 4 ft of arrays...so you have an extra 3 ft of height to share the internal volume), have to be more precise in placement of braces...to keep each compartment the same size.

What are the pros, really?

I want to build the thing with a curved back, and think I've found a good way to do it. If the finals fit the bill for the midrange+ part, I'd love to build an enclosure that will house it along with the midbass array, and look finished. Basically, I'm jealous of your design

 

[jtwrace]

I'm hopefully VERY close to auditioning some Final Sound 400is, which I think would mate very well with a midbass array...so if they are as good as hoped,

when will you do that?

 

[IWalker]

Haha, I don't know...you tell me, o mighty procurer of fine transducers. Have they arrived? Howsabout Sunday afternoon? You don't REALLY need to get anything else done do you???

 

[jtwrace]

Haha, I don't know...you tell me, o mighty procurer of fine transducers. Have they arrived? Howsabout Sunday afternoon? You don't REALLY need to get anything else done do you???

you should be reading my e-mails more carefully...

 

[IWalker]

I claim mental fatigue!

 

[jtwrace]

JonFo,

Can you answer this since I destroyed this thread?

Thanks,
jtwrace

Jon, always appreciate your thoughts/inputs! Thanks!

IB is far from an option at this point. Doubtful that it'll be an option in my next place - I'm pretty much sold on the merits, though. I would definitely give it a try if I had a space that worked. I'm very happy with the quality (and pricing) of my sub right now...so will end up just building 1-3 more (have the 1 box built...will have to build 2 more if I want 4...I wouldn't go for more than 2 in my current space (read:apartment)

Your comments on the MLs having great distortion/power handling even at thundering SPLs is very encouraging. I think the removal of the passive X-over is probably an important step.


I'm hopefully VERY close to auditioning some Final Sound 400is, which I think would mate very well with a midbass array...so if they are as good as hoped, I might forgo the planar tweeter line (use them in another design later on) and just go with a closed back (critical Q) midbass array of 8945Ps. I should certainly give the daytons a chance in a closed back config...but in their current dipole configuration, I've come to the conclusion that they're likely underdamped. (I get under/overdamped backwards...) For pure bass performance below 500Hz or so, there shouldn't be a huge difference between the Daytons and the Ushers....but I'm definitely enjoying the sound from the Ushers in their test box much more than I do the Dayton line. Need to do more experimentation...

On the tweeter front...it might be something about being used to having a huge radiating surface in the treble/midrange (which a line might fix) but I'm not nearly as enthusiastic about the BG tweeters as I am about the usher woofers. Love the woofers to bits...BG I'm considering alternatives too...Also, using something else would allow me to keep the crossover out of the midrange, which I'd prefer.

Question for you...wouldn't an IB also be under/overdamped (whichever one results from having too little backpressure) causing it to have less than ideal response? I was under the impression that a critical Q box was ideal for transient response. I just don't know that much about it though.

Yeah, I was referring to keeping each woofer enclosure seperate from each other. The tweeters have a back-cup, so it probably wouldn't matter if I put them in the same enclosure...but that's a different question.

As I see it - Having seperate enclosures/compartments for each woofer

Pros - ??? More rigidity?

Cons, - can't share internal volume (ie, have a 7ft box, with 4 ft of arrays...so you have an extra 3 ft of height to share the internal volume), have to be more precise in placement of braces...to keep each compartment the same size.

What are the pros, really?

I want to build the thing with a curved back, and think I've found a good way to do it. If the finals fit the bill for the midrange+ part, I'd love to build an enclosure that will house it along with the midbass array, and look finished. Basically, I'm jealous of your design