LaScala mouth extensions for 80-100hz.

[noviygera]

 

GREETINGS!

I've got a pair of the original LaScalla 1 bass bins with K43 woofers and would like to work on them, improve this design. Bracing + reduction of doghouse volume + possible the mouth extension, all experiments for now, possible PA application, NOT home use! 

As is, they roll off below 100hz, maybe 110hz. I'd like to load them down to 80-85hz. Thinking about a horn extension... 

 

Please share your thoughts.

Has anyone modeled LaScalla 1 in Hornresp?

Has anyone tried or modeled an extension in Hornresp?

What would be a good length and width of this extension as well as the flare (would conical be acceptable)? 

Thanks!

[Edgar]

34 minutes ago, noviygera said:

Has anyone modeled LaScalla 1 in Hornresp?

https://community.klipsch.com/index.php?/topic/103773-analysis-of-klipschorn-and-la-scala-cabinets-with-several-drivers/&do=findComment&comment=1144636

 

[noviygera]

Thanks!

I see this:

 

 

So, it looks to me like the extension could be conical, similarly to the 50-90cm "path distance." On the OTHER hand, the loading down to 80-85hz would not be happening in the conical section, right? So is this an exercise in futility? 

 

[Edgar]

1 hour ago, noviygera said:

On the OTHER hand, the loading down to 80-85hz would not be happening in the conical section, right?

People have reported success with corner-loading, and even with turning the cabinet around so that the mouth points into the corner, so it's difficult to make any predictions.

[Marvel]

There is a member here who built some ls style cabinets with the depth a little larger and the sides flared instead of parallel. This accomplished a couple things. It made the horn slightly longer (maybe about 4 inches... can't find the pic). The flared sides also meant there wasn't the 10 inch or so side channels, with the paralel sides, top and bottom. Unfortunately, he didn't test them to get the numbers, but the buyer who got them liked them

 

@tigerwoodKhorns

[tigerwoodKhorns]

11 minutes ago, Marvel said:

There is a member here who built some ls style cabinets with the depth a little larger and the sides flared instead of parallel. This accomplished a couple things. It made the horn slightly longer (maybe about 4 inches... can't find the pic). The flared sides also meant there wasn't the 10 inch or so side channels, with the paralel sides, top and bottom. Unfortunately, he didn't test them to get the numbers, but the buyer who got them liked them

 

@tigerwoodKhorns

I did it with K Horns but never tested them.  They did have very good bass, but not that pretty, a little too wide. 

[OO1]

 

Main issue is your woofers are tired and the K-43 does not produce as much bass as the K-33 ,  as well , the cabs are not as stiff as they should be without   resonance  .

 

 you can laminate 1/4 inch  wood to the side panels , top and bottom , that stiffens the bass bin  , and makes it heavier +  more responsive , all new LS cabs are 1"  MDF .  your speakers may not even be  a full 3/4 inch ,  a 2nd pair of LS would not be a bad idea .

 

next change would be to purchase the new klipsch K-33-E woofer , it has more low end grunt  than a K-43   /make sure the bottom woofer panel  seal  is air tight   .....   updating crossovers    with klipsch caps can bring the network back to factory specs  , if you did use  aftermarket  capacitors  , , start all over  . 

[tigerwoodKhorns]

17 minutes ago, OO1 said:

 

Main issue is your woofers are tired and the K-43 does not produce as much bass as the K-33 ,  as well , the cabs are not as stiff as they should be without any resonance  .

 

 you can laminate 1/4 inch  wood to the side panels , top and bottom , that stiffens the bass bin  , and makes it heavier +  more responsive , all new LS cabs are 1"  MDF .  your speakers may not even be  a full 3/4 inch ,  a 2nd pair of LS would not be a bad idea .

 

next change would be to purchase the new klipsch K-33-E woofer , it has more low end grunt  than a K-43   /make sure the bottom woofer panel  seal  is air tight for optimal performance   .....finally  if the crossovers are Original stock ,  updating  them  with klipsch caps can bring the network back to factory specs  , if you did update the caps with aftermarket  capacitors  , dump them and start al over  . 

Sounds like some mods to me 🥵

[OO1]

24 minutes ago, tigerwoodKhorns said:

Sounds like some mods to me 🥵

oh , ok 

[Edgar]

10 hours ago, tigerwoodKhorns said:

Sounds like some mods to me 🥵

Yeah, it's easy to get caught-up in the excitement of experimentation.

[tigerwoodKhorns]

1 hour ago, Edgar said:

Yeah, it's easy to get caught-up in the excitement of experimentation.

 

Let's all keep our heads cool. 

 

[Invidiosulus]

Adding braces to the side panels really improves the sound of the older 3/4” LS cabs.

if it were for PA use I would probably shy away from laminating on an extra 1/4” of thickness as the extra weight won’t be fun to haul around in one piece.

The industrial model LS have a layer of fiberglass(I think) and aluminum trim which helps to cut down on the side panel vibrations.

If you are sticking with the 3/4” plywood then just add some braces between the doghouse and the side panel like the later Peavey FH-1 used.

The doghouse angle is basically 60° or 30° depending on which way your miter square is referenced.

 

For PA use where you won’t be able to consistently corner load the LS, look into building some (horn loaded) subs.

[noviygera]

This is PA use, installed sound with the need for high output. I do plan to add the bracing but specifically interested if extending the conical horn section will work. 

From what I read the best flare (according to Bruce Edgar is hypex - hyberbolic-exponential). I guess the LaScala is FAR from that.

However, will continuing the expansion of the conical section actually load it down properly?

[OO1]

sounds complicated 

[Bubo]

When does a LaScala cease to be a LaScala ?

 

What Klipsch was very good at was measuring declining marginal returns in design and profitability

With the underlying imperative that the speakers sound good for hours, weeks, and years.

 

Using the LaScala design as a baseline, I believe the dimensions you have to experiment with are

length, shape of the opening, and materials to achieve structural goals. A cement block may achieve zero resonance, but unlikely.

 

I have limited wood working capabilities

and all of my fingers.

 

If it were me, I would buy 2 (4)  sheets of 1 inch plywood, decent quality or MDF which I don't like. And use the rough plywood for the experiments, essentially the same process Kilpsch did 50 years ago. Better materials and veneer are I believe after thoughts.

 

Deck screws and pure silicone calk would speed things along and make it easier to tear down and reconfig the cabinets. For example you could start out with 8 foot horn flares, and keep cutting the sides down taking measurements as you go.  Measure and mark your cuts, then go around with a circular saw if you have a steady hand.  Single and dual driver baffles for the dog house should be swap-able.

 

As a practicle matter, I believe the designers at Klipsch, JBL and Altec tried to limit the depth of their non theater designs to approximately 2 feet. Folding obviously gave Klipsch more length. Altec 820c and probably other designs brute forced it with 2 drivers and 2 foot horns. Mantaray I believe was the 2nd or 3rd generation of this method with a two way crossover, giant upper flared horn and dual driver base with short horns maybe exponential flares.

 

If you have space in the garage, unfold the horn in the mockups, making design changes faster, easier and cheaper. Hinges and calk may allow rapid experimentation and measurement. External 2x4 cross braces would certainly stiffen up the dummies.

 

There is a 15 in low cost woofer that many on here use to freshen up their systems, I would score two of those so I could experiment with 1 and 2 driver doghouse configurations. Something both Klipsch and Altec experimented with and produced as products. 1 driver bins may be simply a cost savings measure using some engineering elegance, where brute force 2 drivers might sound a little better and punchier......

 

I'm visualizing 1 8ft horn, up on saw horses with dual drivers as the design to beat, as you cut away and alternate between 1 and 2 drivers. Kind of like the multi driver side mounted horns klipsch style. I am wondering if garage door weather stripping on the sides ( top and bottom ) and hinges would be good enough for experimenting.

 

The engineers would always listen to me intently, take lots of notes, and get all excited when I was on the white board. When asked if they were going to do it my way, they frequently responded "great product idea", and we thought of a better way to design it while you were talking. Then run out the door to go to work ......

[Bubo]

PS

Given the years the K-horn and LaScala were designed

Tube amps had limited power, and noise may have increased dramatically per additional watt of output.

 

So the folded horn, may have been the way to overcome the amps and driver costs of the day.

 

In modern times, a 2 driver high-efficiency short horn may be optimal and meet or exceed the measured performance goals, while keeping cost on target.

[Marvel]

7 hours ago, noviygera said:

This is PA use, installed sound with the need for high output. I do plan to add the bracing but specifically interested if extending the conical horn section will work. 

IIRC, these are at a single location. You could definitely re-engineer and add onto the horn, but why do that?

 

The easiest thing to do would be to buy or build some Klipsch MWM bins or MWMS bins (dual 15s or single 15). They are are about a 7 ft horn and will totally stomp the La Scala bass.

 

They are an easy build, or can be fould reasonably cheap. Very efficient, as horns tend to be...

 

Here's a pair in my house. Mine are on their sides, so they tilt back. If horizontal they are 45 inches deepx 67 inches wide, approx. 32 high.

 

 

[Marvel]

Also meant to add... you can sometime find for free or low cost. No need to reinvent the wheel. I used a Crown 25 wpc amp to power these. You would want a bigger amp, but you would be amazed at the output.

[noviygera]

Marvel, 

thanks but those will be too big. Already checked into those. So looking for ideas to work with LaScalas. 

[tromprof]

The better route is a good horn sub. It will be a far better solution than any mods done to the LaScala. A tuba table worked well with mine and is not too huge