Very weird LaScala question (designing bass bin)

[Coytee]

Ok, hear me out. I'm going to try to spare all the whats/whys to keep this simple but...(do I ever really do that?)

Not 'would' this work but rather, 'what would it take to make it work?"

We all know what a LaScala looks like. Ok, now, chop the top off and let's only discuss the bass bin. Again, we all know what this looks like.

I'm looking for ways to lower the height of my center LaScala (which is why chopping off the top comes to mind) however, I still have a problem in that, I would have nowhere to place the K510 I'm intending on using unless perhaps, I place it on the floor in front of the bass bin.

This is when I got to thinking weird

Does the nose-cone of the LaScala have to be pointed or is that for cosmetic/build reasons?

I'm going to presume it's more for cosmetic reasons than actually being necessary. After all, how would the driver know the shape of the space behind it as long as that space was of sufficient size?

If accurate, then here's the rest.

Could a bass bin alone be designed to the technical paramaters of the LaScala (internal volume in that cone area) however, instead of making that area pointed, make it square. yes, make it a box.

how to word this... inside this box would be a seperate chamber, dead center in front. Perhaps sealed from the back chamber of the K33 or, if there is some way to do it, not sealed. (this is where you guys come in since I know so little about this)

Put the K510 in this center chamber so it's firing directly forward and surrounding it (behind the motorboard) would be the back chamber for the driver in the woofer bin.

For a real crude way of trying to describe it might be calling it a coaxial design to at least try to get the idea across.

Might need to make the bass bin a bit deeper...I don't know.

I don't think the wife will ever stop rolling her eyes if I set a K510 on the floor in the middle of the room. Truth be told, she won't stop rolling her eyes by the mere presence of the speakers I have but that's a different story.

I'm asking this to try to see if I could have a box built that is of a LaScala bass bin paramater however, alter this so I could mount the 510 in the center of it.

This could be an intersting project. Anyone with drawing skills, willing to try to decypher my comments?

I might add, I do not know the dimensions of the K510 other than to know it should fit inside the tophat of a LaScala. I guess it's about as wide as the K400, maybe not quite that wide. It's a little taller. I don't think it's as deep, even with the K69 mounted.

If I can't make my single LaScala work then this might be a fun project to mess around with.

[Marvel]

OK, I'll bite...

SInce this is for a center, could we mount the K510 vertically? Now we need to know the depth of the K510 with the driver on it. Islander has some of those on his LS, so he could chime in with all the dimensions. I think this would be more like a deeper (front to back) version of the Belle Klipsch, with the K510 mounted in the front.

Interesting... the shape of the LS bass bin is to make the bass horn flare the proper flare rate. But it could be wider and then deeper to mount the horn.

Bruce

[Coytee]

I'd speculate the 510 would need to be horizontal for dispersion?

[Marvel]

I'd speculate the 510 would need to be horizontal for dispersion?

Maybe...

[Coytee]

I think this would be more like a deeper (front to back) version of the Belle Klipsch, with the K510 mounted in the front.

I think you hit it on the head there (without the top of the Belle of course). Is it rude to talk about a topless Belle on the Klipsch forum? [] [:$] [:#]

[jwc]

Richard,

If you want a design from scratch, didn't I post one with two twelves with the 510 in the front/middle of the bass bin?

The other thing is to make the scala bass bin almost the same except that there won't be a flare in the middle...will come out straight forward.....and flare out the side walls at the same "flare rate" as what the center flare would have been. This is an easy build.

In this config, your 510 will mount right in the middle /center.

I mentioned these ideas before.,...but of no interest really.....

Anytime someone would request such a thing....i draw one up...they receive it...then say "cool, thanks"...and i never hear anything else.

jc

[WMcD]

Interesting question.

I looked at the cinema section to see if there is info on the size of the 510. I didn't find any. Maybe someone can help.

But otherwise I have some comments. IMHO.

Overall the pointed nature of the doghouse is that way so as to maintain a theoretical flare. But it is just an approximation. A greater limitation on the bass response is the horn length. Also, once you get below 100 Hz (IMHO) the bass output relies on the woofer resonance. The unit is acting more like a sealed box driver with some small amount of horn loading.

Suggestion 1. If the 510 and driver is not too deep: It might fit into the wedge of open space defined by the doghouse and a sidewall. No special chamber for the 510. If you turn the bass bin on its side, the 510 will be near the top of the unit, which is something which might be necessary for best dispursion into the room. Also, it might be nice to angle the 510 upwards a bit toward the listener.

Suggestion 2. IMHO, you could build a box for 510 and carve out a space for it in the pointy edge of the dog house. One spot is at the center of the doghouse. As you say, co-axial. The other would be at the top of the doghouse. I don't have any clever thoughts on what sort of saw to use to accomplish the carving out. I do believe the anomaly in the resulting mouth either way will not have much effect on the bass.

Suggestion 3. Naturally the addition of the sealed box for the 510 will subtract some of the back chamber volume in the doghouse. That will raise the resonance freq of the woofer a bit. I doubt it will hurt too much, particularly because when used as a center, you're not striving for the deepest bass from the woofer.And maybe it would be a bit better. My thinking is that the resonance stretches response down but only if you have them in a corner where the freqs are amplifed by the room / corner. Otherwise, there may be a hole in the response above resonance and it could work well to fill it in with a higher resonance freq.

Suggestion 4. If you do the box for the 510 intruding in the doghouse, and you want to maintain the volume behind the woofer, there is a way to make up for it. This is a la the early change to the K-Horn. PWK was looking for more volume and modified the design to use otherwise sealed off volumes of space.

In the case of the LS, there is a volume of spaces (two) defined by the ramps or wings which define the initial flare. That volume is sealled off and one wall of the space is the back wall of the doghouse. It would be possible to get an electric drill and spade bit into the doghouse and drill a number of holes into those volumes. In this way, the back chamber of the doghouse will include these otherwise hidden volumes. In the case of the K-Horn, PWK called the new found volumes "sinuses." In translation? "bays". like bays off the ocean.

Wm McD

[WMcD]

Hmm, a commercial for the Fein Multimaster was just on the cable. If you have to make cuts in a confined area, it might be what you need. OTOH nothing actually works in reality as well as it does on TV.

Wm McD

[DrWho]

Are you wanting to modify a lascala to work, or you willing to start from scratch on the bass bin?

I would seriously consider one of the designs that JC drew up before. One of the nice things about this is you could employ some of the lessons learned since the lascala and probably even yield better performance in some ways.

I might also add that a center duty speaker doesn't need to dig as low either...

[Coytee]

didn't I post one with two twelves with the 510 in the front/middle of the bass bin?

I have/had no idea.

If I do not install a screen downstairs, this will be a moot point. If the wife is 'happy' with a 510 sitting on the floor in front of a chopped (or not) LaScala bin, this will be a moot point.

Frankly, I'm hoping this is a moot point (screen goes up but, she's ok with 510 sitting on floor) since I'm not a woodworking of any kind. I usually don't pay a great deal of attention to design threads because they are usually over my head. I've always been a plug/play/smile kinda guy...not the creative type that it takes for someone to put a pencil to paper.

[Coytee]

Are you wanting to modify a lascala to work, or you willing to start from scratch on the bass bin?

My real hope is that I can make the current box I have, work somehow.

Absent that, I'd be intrigued about starting from scratch. The only real limitation is it would have to be no taller than (I forget) something like 34" however, if I could cut that back to 28/29 inches it might be better.

I fiddled around with a portable screen, setting the top of it near the ceiling and raising the bottom to give me the general paramaters of say, a 106" diaginal screen. The bottom of the screen would have been right at 36" if I recall. I had some vague thoughts as to wondering if I would have felt more comfortable if the entire image was dropped about 10" from it's centerpoint.

My brother in law had to take his projector back so I didn't get to play around much more to try to verify my thoughts. It did however, get me down to a 106" diag screen over something larger like I was originally wanting to do so in that regard, it was a worthwhile experiment.

[DrWho]

Are you wanting to modify a lascala to work, or you willing to start from scratch on the bass bin?

My real hope is that I can make the current box I have, work somehow.

Just keep in mind that the pointed nose on the lascala is there to satisfy the flare rate for the horn. Anything you do to change around the lascala is going to change the flare rate which can have a huge effect on the frequency response if you're not careful about it.

Before making the whole rear chamber and flare a square box, I would probably look into just cutting out a notch so that the compression driver and horn can tuck inside the same rear chamber as the woofer. Then you would just be interrupting the flare (making it a box) in the area behind the compression driver. You'll lose some of the volume in the rear chamber, but for a center channel losing a little low frequency extension shouldn't be a huge deal. You could probably make the cut using a jigsaw or something?

[Islander]

Absent that, I'd be intrigued about starting from scratch. The only real limitation is it would have to be no taller than (I forget) something like 34" however, if I could cut that back to 28/29 inches it might be better.

As you may know, La Scala cabinets come in two basic versions: top-loading woofers from about 1975 and earlier, and bottom-loading woofers from about 1976 on. Externally, the difference is that the later model has a 1" riser under it to clear the woofer access door. That model is 35.5" tall, while the earlier top-loading model has a flat bottom and is 34.5" tall.

If you were to cut off the HF section and have just the bass bin, you could turn it over (upside-down) and remove the riser to save 1" in height. Naturally, you'd have to relocate the crossover to what would now be the top of the cabinet. That shouldn't be too difficult. The crossover could be mounted to one side of the woofer door, behind, or even on top of it, since you wouldn't have to work around the bulky K400 horn if you're using a K510. For that matter, if you're going JubScala with an active crossover, it wouldn't even be there.

The K510 is 15" wide and 9" tall, with 1" flanges at top and bottom (the side flanges are a bit narrower). You could front-mount the K510 to the inverted LS bass bin (its flanges already have mounting holes) and save another inch, so your total height would be the bass bin minus its riser, plus 8" for the K510.

If you want the speaker to look a bit more finished and have basic skills with a router, you could route a recess into the bass bin for the bottom flange of the K510 so it would sit flush with the front of the bin. That would also minimize or eliminate any diffraction effects or other anomalies caused by the step from flange to cabinet front. The recess would need to be 15" wide, 1" tall and 1/4" deep.

That configuration would give you a total height of about 32". If you really needed to lose one more inch in height, you could then trim off the K510's upper flange, although there would be at least a theoretical loss in stiffness of the horn, plus a loss in resale value.

Would a speaker like that be low enough for your application?

[Coytee]

Just keep in mind that the pointed nose on the lascala is there to satisfy the flare rate for the horn

Question: Is it the point of the nose or simply the area behind the woofer? What if instead, the 'cone' was oval? rectangular? BUT... had the same area. I thought the area was the key, not the shape?

[Coytee]

As you may know, La Scala cabinets come in two basic versions: top-loading woofers from about 1975 and earlier, and bottom-loading woofers from about 1976 on. Externally, the difference is that the later model has a 1" riser under it to clear the woofer access door

Yes, knew that

That model is 35.5" tall, while the earlier top-loading model has a flat bottom and is 34.5" tall.

I did NOT know that!

if you're going JubScala with an active crossover, it wouldn't even be there.

It will be used with an active. Although it's out being played with by someone, I already have a Dx38 for this purpose.

Would a speaker like that be low enough for your application?

I couldn't be sure. Right now, my measurements were taken by using a portable screen (100" so it was a big one) and setting it up. When I measured the bottom height, I measured to the bottom of the canister that the screen rolls into. I don't really know how that measurement location correlates with the bottom tip of an actual ceiling mounted drop down screen. Right now, all I have to go on are some general parameters.

Originally, I thought a screen that fell to 36" from the floor would give me enough room to slide the LaScala under it. I then remembered that I'm planning on wrapping my LaScala with another layer of 3/4" plywood to give it a new skin and to help beefen up the side walls. I was thinking I would add this skin to not only the front motorboard (to give me a fresh surface to mount the K510 in a traditional location) but also add it to the top of the speaker which would raise my height issues. That's when I got to wondering about cutting the top of the box off and getting a little weird in my thinking.

[seti]

How about a jubilee with two 6" or 8" woofers scaled down to a smaller size for a center channel.

[Islander]

I then remembered that I'm planning on wrapping my LaScala with another layer of 3/4" plywood to give it a new skin and to help beefen up the side walls. I was thinking I would add this skin to not only the front motorboard (to give me a fresh surface to mount the K510 in a traditional location) but also add it to the top of the speaker which would raise my height issues.

There's no need to add stiffness to the top and bottom of the bass bin, since they're already stiffened by having the doghouse attached to them. It's the large unrestrained side areas of the bin that have the flexing issue.

[Coytee]

There's no need to add stiffness to the top and bottom of the bass bin, since they're already stiffened by having the doghouse attached to them. It's the large unrestrained side areas of the bin that have the flexing issue.

Yes, I am aware. I was just thinking that it would make the entire unit look more whole. Something psychological in me about putting new sides and a new front (where the K400 mounts) without adding a new lid.... just hits that retentive nerve in me saying it needs a new top as well!

[LARRY]

Coytee,

Check out the 1/2 height J2 at Soniphase.com. This is a design by Dana Moore that you will find interesting and may help in your quest.

Larry

[seti]

Or a split half height jubilee with only one twelve.