Line Array Speakers : Modular, Expandable, Out-of-the-Box Design for in-home use

[Alexium]

That will give a lot of lobing:
View attachment 243255

What's this software?

 

[voodooless]

What's this software?

It's XDir:

Tolvan Data

 

[benanders]

As suggested by the software analysis (thank you @voodooless), the Strada 2 monitor should sound problematic. NRD test results also support that prediction.

But, Strada 2 (stereo pair) sounds excellent at high frequencies, despite any contradictory performance test predictions / results. Seems an inexplicable (truly not explicable, grin) discrepancy between what’s on paper and what’s in reality. I don’t profess to understand why, but the listening experiences among reviewers/owners in the past decade remain consistently positive. That’s partly why I chose to try a line array with the Strada 2 (wasn’t exactly my idea first, if you search Gallo 5LS…).

WHY a Line Array INside??

I wanted two main things from what could be an ever-evolving project.

(1) Very large / tall sonic image and believable dynamics achieved without blasting SPL. IOW, a convincing wall of sound.
(2) Service a long room at both sitting and standing heights, again without blasting SPL.

Even the crudest big line array should permit those two goals, but life is not just about wants; I had several logistical restrictions, too (none of which must apply in a dedicated-forever listening room).

(1) Expandable - add / remove units as needed based on ceiling heights.
(2) Modular - disassemble / pack away in little space and, preferably, ship easily, too.
(3) Non-obstructive to front wall view - no sense in blocking a big window (see attached pic).

Again - project not finished, may never be and doesn’t need to be. But baby-stepping in the right direction for my goals.
Software testing? I’ll get there yet!
Experimentally-sound ( = statistically robust) qualitative sampling? WIP and can elaborate, if of any interest.

Regarding integrative evidence (both empirical and qualitative) supporting indoor LA’s, has anyone else looking here actually read every page and associated links of @Wesayso diyAudio thread? Don’t attempt it in an afternoon - it works better for those of us who’ve tagged along for years.

 

[benanders]

Ok I see ...

I don't see the point of a line array in such a small room. Try measure your FR at different points you will see the problem.

Room size is subjective: length and height permit exploiting near-field LA behavior in my case. The side walls are too close and should (but won’t) be treated for optimal results.

My setup keeps one trick pony in the stable no other non-PA LA has, too. With a quick swap of two cables, it becomes a conventional stereo pair at either sitting or standing height. Delicate critical listening and philharmonic orchestra concert-pummeling (or live Zep-mediated head-banging) SPLs don’t always best come from the same speaker. I’m fortunate to have a workaround

 

[Snake Oil is life]

And, especially, to allow (financially interesting) very large audience with decent (enjoyable) sound level for everyone, while respecting the very strict maximum SPL regulations (originaly 105dB SPL at any place in the venue for 15 minutes in France, as an example - now reduced to 102dB)

Wow 102 dB now ! Clubs owners must be crying ... But you start having hear loss after 15minutes at 100 dB ... I always used my custom earplugs when working in heavy sound volumes ...

 

[Snake Oil is life]

Room size is subjective: length and height permit exploiting near-field LA behavior in my case. The side walls are too close and should (but won’t) be treated for optimal results.

My setup keeps one trick pony in the stable no other non-PA LA has, too. With a quick swap of two cables, it becomes a conventional stereo pair at either sitting or standing height. Delicate critical listening and philharmonic orchestra concert-pummeling (or live Zep-mediated head-banging) SPLs don’t always best come from the same speaker. I’m fortunate to have a workaround

Another thing i did not mention with line arrays , as their conceived to project far , in a closed room they strike hard on the opposite wall generating echos and unwanted reverb.

 

[benanders]

Another thing i did not mention with line arrays , as their conceived to project far , in a closed room they strike hard on the opposite wall generating echos and unwanted reverb.

Thankfully my “back wall” isn’t much of a back wall, broken up by floor-ceiling furnishings and a wide hallway.
I suspect the array’s inability to reach the true ceiling (big wood plank beam with HVAC: room pic) is more an issue for problematic reflections, that is, other than the obvious sidewalls. Measurements will hopefully give some insight on significant effects.

Now accepting suggestions on favored mics for such purposes

 

[voodooless]

Now accepting suggestions on favored mics for such purposes

Get any of the two MiniDSP ones. Whichever you feel comfortable with. They should both do an excellent job.

 

[Snake Oil is life]

Thankfully my “back wall” isn’t much of a back wall, broken up by floor-ceiling furnishings and a wide hallway.
I suspect the array’s inability to reach the true ceiling (big wood plank beam with HVAC: room pic) is more an issue for problematic reflections, that is, other than the obvious sidewalls. Measurements will hopefully give some insight on significant effects.

Now accepting suggestions on favored mics for such purposes

honnestly as long as its a mesasurement mic there no difference. I own a castly klark teknik mic and a behringer one and measurements are the same. MiniDSP one look nice and are cheap

 

[Rja4000]

honnestly as long as its a mesasurement mic there no difference. I own a castly klark teknik mic and a behringer one and measurements are the same. MiniDSP one look nice and are cheap

Yes
Measurements will be awful with any.

 

[benanders]

Yes
Measurements will be awful with any.

The phrase “It’s not what you say, it’s how you say it” comes to mind.

You wanna confirm that you meant unregulated / indoor line arrays won’t measure well, and not the suggested MiniDSP mics?
Ambiguously-worded dogmatic claims might be more accurate than not, but they’re also less helpful than you might assume.

 

[Rja4000]

The phrase “It’s not what you say, it’s how you say it” comes to mind.

You wanna confirm that you meant unregulated / indoor line arrays won’t measure well, and not the suggested MiniDSP mics?
Ambiguously-worded dogmatic claims might be more accurate than not, but they’re also less helpful than you might assume.

I meant the first one.

It may be dogmatic -it actually is- but theory is against you.
And, so far, you just objected with subjective personal impressions.

But you're very welcome to prove us that the reality is different. So please buy one of those cheap microphones - if this is actually as bad as theory predicts, it will not be anything subtile, so the mic quality won't matter- and come back with measurements to support your claim.

You came here knowing perfectly that what you present is provocative. Now you have another provocation in return.

Will you take up the gauntlet?

I'd really love to be proven I'm wrong on this.

 

[Rja4000]

If you would think a little harder, a line array concept in a home might make a lot more sense than you suggest here. Harman curves are the hot thing here, lets see what a line array can do in-room (see middle left graph):
View attachment 243260

Granted, this is a frequency shaded array with closer center to center spacing than the OP has. But still, it's a line array designed for in-home use and the DI and Power response should give you pause and make you think about your statement a little more.

What we see is that horizontally it has a CD like coverage, due to using 3.5" drivers in the array. Vertically it is like a beam of sound. except for a few lobes on top, as these are the result of the specific center to center spacing of this particular design. The result? Very even coverage over a wide area (that's what that Power & DI graph is trying to tell you too) and even over a large enough area to cover seated and standing, while almost totally avoiding floor and ceiling reflections.

Did you notice to what frequency the beam control spans? What size horn could give you that kind of behavior? Which is another plus for the array in a home, space saving. Would you believe this speaker fits on an A4 size paper?

Let's see an in-room prediction of a single 3.5" driver vs an array of 25x 3.5"drivers and the influence of floor and ceiling of both inside a room, horizontally, they will have the same coverage pattern...
View attachment 243261
Do I need to explain which graph is which? Or is it clear that the array is the one with more output.

Exactly the same setting on floor and ceiling absorption. I do realize this might not convince you right away, as it goes against that "painting with water balloons" idea, don't it?
But maybe, just maybe, it will make you think a little harder about the usefulness of arrays inside a home. I hope you get that message loud and clear, as that is what arrays sound like, in a home .

It should make you think about your attitude, barging in on a post/thread made by the OP, that clearly was made out of sheer enthusiasm, with all that negativity. It could have been brought with a little more tact, and quite frankly, with a better understanding of the use of arrays in a home.

Impressive.
Thanks for sharing.

I think it is feasible to design a line array for home use.
It's a matter of proper transducers size, spacing, angle, ... and flexibility of setup to adapt to room (with adapted software).
(Your room will have to have high enough ceiling, though)

But I'm almost certain the system the OP showed us in picture can't perform properly.

It's not a real line array, to begin with. Just a set of speakers attached together.

 

[benanders]

Impressive.
Thanks for sharing.

I think it is feasible to design a line array for home use.
It's a matter of proper transducers size, spacing, angle, ... and flexibility of setup to adapt to room (with adapted software).
(Your room will have to have high enough ceiling, though)

But I'm almost certain the system the OP showed us in picture can't perform properly.

It's not a real line array, to begin with. Just a set of speakers attached together.

@Rja4000 thanks for specifying. However, please realize: LA’s don’t inherently need a ceiling that’s “high enough”. Floor-ceiling height is relevant to CBT’s (bottom-up curve) and J-arrays (top-down curve), whereas spacing of outermost transducers from vertical boundaries (i.e., floor and ceiling, which [theoretically] act as adjacent transducers) may be of greater relevance for straight LA’s.

Reflectivity of floor/ceiling should [theoretically] be more important than height.
Floor-ceiling height for straight LA’s is mostly a matter of transducer vertical dimension(s) and/or impedance limitations based on the model(s) of choice.
Straight LA’s ideally stretch their radiating surface all the way from floor to ceiling, literally. Many straight LA’s fall short of this (pun!). In that vain, some ceilings may be too high for LA’s.

Incidentally, how tightly-spaced tweeters should be depends on the given tweeter model’s vertical behavior, and on required length of near-field listening, before destructive interference and/or beaming should occur from angles of overlap in dispersion, if any.
Many tweeters lack significant vertical dispersion; mine do not. @Wesayso does not use tweeters, rather woofers with considerable c-t-c distance. Perhaps both @benanders and @Wesayso LA’s can’t perform properly because Yousayno, @Rja4000 ?

It’s fine to be skeptical of anything you can’t hear in person, but I think it’s premature for anyone to dismiss my whole project, as if I’d cavalierly stacked a bunch of conventional bookshelf speakers without first investing due diligence, planning, some trial and error. For you to chalk it up as “just a set of speakers attached” is in error. So a bit more patience, please. Maybe a lot more, depending on upcoming work schedule etc.

With regards to discussion of indoor LA’s and conclusions based on an absence of software output, might I draw your attention to an in-house thread - a review by @amirm

A Visit with Bob Carver and His Amazing Line Source Speakers

I owned my first Carver product back in 1982 or so. It was a 200 watt receiver with amazing FM tuner and light as a feather due to voltage rail switching that increased its efficiency. Fast forward some 35 years later and I was finally face to face with Bob Carver organized at an event by our...

www.audiosciencereview.com

Many audio gurus were there, yet few graphics came of the occasion, grin. There are good points in that thread to help you think more about unconventional LA’s indoors.
You really should (if you haven’t) just hear one in person, to know whether indoor LA sound is for you.

 

[Ericglo]

I won't quote the posts, but I had to respond to LA skepticism in home environments.

I see Wesayso has already posted. For the person who mentioned Linkwitz, @fluid chose a LA over his Linkwitz speakers.

From what I have seen, heard and read, the best LAs are floor to ceiling (or close to it) for an infinite array.

Almost every year at Cedia, Wisdom is the top audio demo with LA speakers with planar drivers. Since they are going into a lot of home theaters, I doubt the rooms are as big as the OPs. IIRC my friend Arrow was running Steinway LAs in his demo with the Christie Eclipse(the apex of projectors).

I don't have any pictures of Wisdom's big demo, but I do have one of their small demo. It still sounded good in a noisy convention. The big demo had probably eight foot tall LR speakers with a twelve foot wide center.

 

[BenB]

Another thing i did not mention with line arrays , as their conceived to project far , in a closed room they strike hard on the opposite wall generating echos and unwanted reverb.

Once again I come across the myth that just wont die. In-room, the sound from a line array attenuates at a similar level as the sound from a single speaker. This has been tested by a line array owner on this site, and verified. The reason is that in a room with floor and ceiling reflections, even a single speaker constitutes a sparse array when you factor in the vertical reflections. Thus even a single speaker experiences something closer to 3 dB of attenuation for doubling of distance, rather than 6 dB (once you are more than a few feet from the speaker).

 

[Rja4000]

It’s fine to be skeptical of anything you can’t hear in person, but I think it’s premature for anyone to dismiss my whole project

I don't judge your project in any way.
Just note you may perfectly do your project just fine... and end up with poor results.
(That's what I usually call "the verdict of reality".)

Please come back with some measurements.
Until we see them, I'll remain skeptical, if you don't mind.

 

[benanders]

That will give a lot of lobing:
View attachment 243255

@voodooless I looked back and realized the Hz value / distance is off in this calculation - I must not have made it clear in my initial reply to you - sorry for that.

350 mm is vertical distance between tweeters, = 350 mm between 6 kHz and up.

89 mm is the distance between woofers = 89 mm between 6 kHz and down.
89 mm is by original design of the speakers.

Spacing of tweeters in the original designer’s version of a LA with this type of speaker (5LS) was ~130 mm, but vertical attenuation of those tweeters was much stronger than those I’m using, and the handover crossover ( ) was significantly lower.

 

[benanders]

I don't judge your project in any way.
Just note you may perfectly do your project just fine... and end up with poor results.
(That's what I usually call "the verdict of reality".)

Please come back with some measurements.
Until we see them, I'll remain skeptical, if you don't mind.

@Rja4000 given the inconsistency of your remarks in this thread, let’s make things straightforward. If you look at the measurements @voodooless kindly screen-captured from the YouTube review of a single version of this speaker model:

Horizontal

Vertical:

…would you consider that speaker to have much chance of sounding right?
Would you give the speaker model any further consideration at all?

 

[voodooless]

…would you consider that speaker to have much chance of sounding right?
Would you give the speaker model any further consideration at all?

Double no.