Forte and Chorus bracing, gaskets and stuffing

[tigerwoodKhorns]

Forte and Chorus bracing, gaskets and stuffing:

 

OK, have Fortes and Chrous completely apart.  Three things:

 

1.     Gaskets - the gaskets all look OK, no tears or crumbling, but very thin.  Do these need to be replaced? 

 

Partsexpress has some foam tape, but it just looks like regular Home Depot door weather seal.  Also looks kind of thick.They also have rope caulk, but I want to avoid any thick seals as the drivers need to set in the motorboards properly. 

 

https://www.parts-express.com/Speaker-Gasketing-Tape-1-8-x-1-2-x-50-ft.-Roll-260-542?gclid=EAIaIQobChMIvbzm4aTp9QIVtBx9Ch1_TQOxEAAYASAAEgLmiPD_BwE

 

 

2.  Speaker insulation.  This one is interesting.  The Chorus have two foam pads each 11.5 x 27 inches.  One along a side and one along the top and a partial side.  Clearly using one size for production.  Is this a very specific amount of stuffing?  If so, here is where it gets interesting.  The Fortes have the exact same stuffing, same size and two pieces in each.  if this were carefully calculated, shouldn't each have different sizes? 

 

I have a bunch of egg crate stuffing that has been sitting for over a decade that I can replace this with.

 

 

3.     Bracing.  OK, these are very nicely constructed using some really nice looking 11 ply 3/4" plywood with all seams cleated, stapled and glued. 

 

But when I knock them with my knuckle, with drivers installed or removed, you definitely hear resonance.  Even the tops which have no openings and are stiffer because of their shorter length.  When I tap other speakers on any surface (Palladiums, JBL L100s made of MDF and B&W 805s) just a short thud.  Way less resonance.  I was not going to brace these, but I will have to dust off the table saw for some stands, so I think that I will go down this route.  Looks like all sides can use stiffening. 

 

 

 

[jason str]

Furring strips work nice, don't go crazy with bracing.

If the old gaskets look reusable use them, same with the foam sheet.

Saw the progress, nice work.

[tigerwoodKhorns]

24 minutes ago, jason str said:

Furring strips work nice, don't go crazy with bracing.

If the old gaskets look reusable use them, same with the foam sheet.

Saw the progress, nice work.

Is the resonance part of the sound character of the speakers? 

 

I did notice on the new Cornwalls they added bracing and the new La Scalas have 1" MDF walls - nice and 'dead'

[jason str]

6 minutes ago, tigerwoodKhorns said:

Is the resonance part of the sound character of the speakers? 

 

I did notice on the new Cornwalls they added bracing and the new La Scalas have 1" MDF walls - nice and 'dead'

Resonance is something you don't want. I try to avoid MDF, build it right and there's no issues.

[tigerwoodKhorns]

MDF is horrible as a material to work with, toxic dust, smelly, blowout screws, but it is dead. 

[pcbiz]

Add insulation to the mid horns. Kilmat is what I used. This will take out out the midrange honk completely. The mids will also blend much better with the highs and lows.

 

Cut some solid wood risers to fit your Chorus. A local carpenter made mine. They look just like the new risers Klipsch uses for the current Forte and Cornwall. The new style risers tightened up the bass very nicely. I was totally surprised at the sonic upgrade; I didn't even know the speakers had resonance issues. I'm pretty sure this is why Klipsch went to this new riser style.

 

Replace the wiring between the crossovers and drivers. 10AWG pure copper wiring gets more current to the drivers, and that little electron boost gets you a nice rise in presence, volume, and detail across all frequencies. The current production La Scalas use thicker wire, so I borrowed the idea from them.

 

If you're thinking about the tweeter, get Dave A's SMAHL tweeters for your Chorus. The titanium upgrade for these tweeters is nice, but Dave's tweeter is great.

 

 

 

 

[StevePaul]

1 hour ago, pcbiz said:

Add insulation to the mid horns. Kilmat is what I used. This will take out out the midrange honk completely. The mids will also blend much better with the highs and lows.

 

Cut some solid wood risers to fit your Chorus. A local carpenter made mine. They look just like the new risers Klipsch uses for the current Forte and Cornwall. The new style risers tightened up the bass very nicely. I was totally surprised at the sonic upgrade; I didn't even know the speakers had resonance issues. I'm pretty sure this is why Klipsch went to this new riser style.

 

Replace the wiring between the crossovers and drivers. 10AWG pure copper wiring gets more current to the drivers, and that little electron boost gets you a nice rise in presence, volume, and detail across all frequencies. The current production La Scalas use thicker wire, so I borrowed the idea from them.

 

If you're thinking about the tweeter, get Dave A's SMAHL tweeters for your Chorus. The titanium upgrade for these tweeters is nice, but Dave's tweeter is great.

 

 

 

 

The LMAHL V2 is what is called out for the Chorus/Chorus II, I believe.

[jason str]

On 2/5/2022 at 3:48 PM, tigerwoodKhorns said:

MDF is horrible

Yes

[001]

think i recall reading on here recently that the resonance is part of the design on fortes & chorus etc.  there was a long thread on the AK forums i posted here a year or so ago where a guy did some major mods to the F3 that included the common internal bracing & lots of added damping material... the results were that they lost bass & upper bass impact. 

 

while i do agree forte1/2 & especially chorus1/2 have a lot of resonance/ringing when slapping the sides, i tend to side with the engineers that designed them knowing they did this & it was part of the characteristic of the speaker.  adding some damping to the horns & woofer/passive baskets & maybe a little extra to cabinets probably wont hurt, but getting carried away with bracing on a speaker that wasnt designed for it might have diminishing returns.