DIY Project Proposal - Pseudo LaSallas from Forte parts?

[FauxHall]

I've got a pair of Forte IIIs that I trying to get the IV upgrade kits. If successful that will leave me with the original tweeters, mid-ranges, and cross-overs, pieces of no value to me as I live in an apartment with no shop and no room nor space for more speakers,

Seems like a valuable bunch of nearly new parts for our enterprising DIYers here at AK. Maybe someone already has ideas?

My current fantasy would be to make Pseudo LaSallas out of the III's surplus-ed parts. Build a top box for the horns (like real LaSallas) but rather than a horn loaded bass, build a big ported box. Bi-wire or even bi-amp with an internal plate amp like a subwoofer.

The bass-to-midrange crossover is at 650 Hz so getting a bass driver and enclosure to match up could be a challenge, especially with the current high overall sensitivity of 95 dB/Watt. I haven't a clue how to do so so I'll leave the fun part to you guys.

If someone thinks they'd like to take this project on, I'd be happy to sell the parts as a kit. I'm sure other Forte III owners who have done the upgrade will have the same need for their replaced parts so there is a broader supply out there. I'd reuse the shipping cartons the IV parts came in as they should fit. Note that shipping from the UAE to the US or Europe won't be cheap but these parts aren't too heavy.

Here's the test chart from Stereophile that might give you a place to start.

 

[Gigantic]

what makes the LaScala what they are is that they're entirely horn-loaded from the bass bin to the tweeter. the 95db sensitivity you quote is combination of the twitter and mid horns, which measure close to 105-107 db sensitive and the woofer, which is significanty less sensitive. you would need to attenuate the mid and tweeter with either an auto former or an L-Pad to match which ever woofer you select.

 

[FauxHall]

what makes the LaScala what they are is that they're entirely horn-loaded from the bass bin to the tweeter. the 95db sensitivity you quote is combination of the twitter and mid horns, which measure close to 105-107 db sensitive and the woofer, which is significanty less sensitive. you would need to attenuate the mid and tweeter with either an auto former or an L-Pad to match which ever woofer you select.

Good start. Thanks.

That point was why I mentioned plate amp for the bass so you could maintain high sensitivity of the whole.

Maybe there's another way?

 

[Gigantic]

Your speakers are only as sensitive as the least sensitive component. In the Forte III and most horn loaded speakers, that’s generally the woofer. Per your idea, placing the horns in a separate enclosure is t the best idea, as you’ll want the additional volume of that enclosure to add additional bass extension. If you want a sealed enclosure, that will also limit bass extension. IMHO, bass reflex is the way to go and using those parts, you have a number of options: #1 is to do a forte style clone, but ported. Crites has a CS1.5 that takes a similar approach, albeit is a 2-way. Similarly, you could do a Chorus 1.5 clone using a 15” woofer and the leftover parts. Or, you can spend more and get a passive radiator to do a Forte 3 clone or a hypothetical chorus 3 if you use a 15” woofer. You could also do any number of additional things, but the 4 I’ve listed are the most obvious and simple alignments.

Since you mentioned selling the parts, this should probably be in the Barter Town section.

 

[Sammythebull]

Interesting and thanks for starting this thread. I have Forte iii and was considering the upgrade kit also. Re-purposing the parts is an intriguing idea and maybe makes the upgrade kit more attractive (tbh I’m on the fence). Assume you made a new cabinet for the removed parts, either in this forte 3 clone or chorus 3 notion, where could those woofers and passive radiators be acquired from?

 

[Gigantic]

You can get them from Partsexpress.com if you do your research, you can improve on the original.

 

[FauxHall]

Think of the thread as a call for feasibility studies on how to recycle these nice parts.

Why not Psuedo K-Horns?

 

[Gigantic]

Think of the thread as a call for feasibility studies on how to recycle these nice parts.

Why not Psuedo K-Horns?

if you're going to do anything like a LaScala or a K-horn, those would be among the last horns that I'd consider. It's not that they're bad, it's just that they're small and matched with a bass bin as used in the aformentioned speakers, they'd be horribly outclassed and mismatched. They're better suited for a compact 3-way speaker that utilizes a direct radiating woofer. For the price you can get for selling them on eBay, you can get much better horns and drivers and have money left over. There's a maxim that's worth repeating: A bigger horn is a better horn.

 

[FauxHall]

So this looks like a 15 inch candidate for the new woofers although it is rated at 4 ohms.

For the bass bin, one could design a bass horn, a transmission line, a sealed acoustic suspension, or a ported box. I have no idea how to choose much less design something like this project.

But it does sound feasible so when I complete the upgrade of IIIs to IVs, I'll offer then on Barter Town and see how much people think they are worth.

GRS K-33-4 Replacement 15" Woofer for Klipsch Klipschorn, Belle Klipsch, Cornwall, and Lascala Speakers

GRS K-33-4 Replacement 15" Woofer for Klipsch Klipschorn, Belle Klipsch, Cornwall, and Lascala SpeakersGRS K33-4 Replacement 15" Woofer for Klipsch SpeakersA worry-free replacement for your favorite Klipsch cabinetThe GRS K-33 is a 1:1 drop-in replacement for the Klipsch K-33 woofer designed to...

www.parts-express.com

 

[Gigantic]

It's worth reading the DIY LaScala threads in the Klipsch Korner. A number of us have done builds that surpass the originals in SQ. Or don't; you seem to have made up your mind and are asking for validation, rather than advice.

 

[FauxHall]

It's worth reading the DIY LaScala threads in the Klipsch Korner. A number of us have done builds that surpass the originals in SQ. Or don't; you seem to have made up your mind and are asking for validation, rather than advice.

You misread my intentions. To repeat, how feasible is it to reuse these nearly new parts for a DIY project?

I'm also curious on how that might work.

If I read you right, you are saying do-able.

Thanks for your contribution.

 

[Gigantic]

previously I mentioned that your best options for the crossover, mid and tweeter horns are:
ported Forte inspired speaker.
or, get a pair of 15" passives and a suitable 12" speaker and build Forte3 clones. This is the path of least resistance, as the cabinet dimensions are easily replicated, you just need to choose a woofer.
or
Get a pair of 15" passives and a suitable 15" speaker and build a theoretical Chorus 3 clone. This is the path of least resistance, as the cabinet dimensions are easily replicated from Chorus 2 dimensions, you just need to choose a woofer.
fwiw, the GRS speakers are not particularly good. They measure slightly worse than the K33, which is sub optimal by contemporary standards. you'll be better served by the K48E or its Eminence equivalent or any number of other woofers. Again, check the diy threads in the korner. we've used woofers from Eminence, Celestion and JBL that perform significantly better than the old Klipsch k33 woofers. When I built my LaScala inspired speakers, I spent a lot of time pouring over Thiele Small charts to determine what speaker would work best for my projected and emulated needs. I strongly recommend WINISD and HornResp to figure everything out.

 

[FauxHall]

Looks like I'll have to transship the kits via a relative in the US to the UAE.

Once I get the swap done I'll offer on Barter for some intrepid speaker builder to have fun with the parts. They can live out my fantasy!