[Woodsage]

The fifth rule is "If You Drink, Don't Drill"

😂 Back in the day I wouldn’t have gotten much drilling done....

I’m sure you remember back before all the fun stuff was taken away from blue collar work. Granted it wasn’t like The Wolf of Wall Street but we definitely had us some fun!

[Josh Mo]

Awesome thread. Knee deep in the project as we speak, excited to talk about sonic differences. Fully taken apart, cutting up braces and about to glue them all in and dampen the interior of the cabinet. 

I'm new to modding Klipsch speakers, but wondering if anyone has experience with damping of stiffening up the horns. Tyson and Danny threw a piece of NoRez on there, but would it be better to Dynamat the rear to kill reflections, add mass, and possibly stiffen things up a bit? Would this cause undesirable sonic changes that I'm not thinking of? There are pics in earlier posts where other Klipsch modders did do this to other speakers (clay, bitumen, dynamat, etc), but just curious as to what the rest of you experienced modders would do.

I suppose this would go for the stamped steel baskets of the woofer and passive radiator too. Would it be better to Dynamat these to kill reflections and mass load the driver a small amount?

[Tyson]

Dynamat is an excellent choice.  Use it on all the frames of the drivers.

[Danny Richie]

What Tyson said is correct.

Or you you have some left over pieces of No Rez you can use that. You can also peel the foam layer off and just use the damping layer.

[Sonicjoy]

While on this subject what about managing the back wave reflections from the spider frame itself especially on midrange drivers.

Vandersteen designs his drivers with minimal surface's that will bounce the back wave of the driver back through the cone. Is there any material that can be placed inside the spider frame that will absorb that range of frequencies? Would NoRez with the foam work? Anyone experiment with this?

[Tyson]

While on this subject what about managing the back wave reflections from the spider frame itself especially on midrange drivers.

Vandersteen designs his drivers with minimal surface's that will bounce the back wave of the driver back through the cone. Is there any material that can be placed inside the spider frame that will absorb that range of frequencies? Would NoRez with the foam work? Anyone experiment with this?

Wouldn't that affect airflow from the rear of the driver in a negative way?

[Sonicjoy]

I don't know that's what I am wondering. The vandersteen design turns the legs of the basket 90 degrees so they are parallel to the air flow for minimum resistance and surface area including the magnet structure to minimize bounce back through the cone.

Here are a couple pics I found:










 

[imom]

Are there no spectral decay plots available? I thought they were mentioned in the Youtube video.

[Swann36]

This is a great thread and the one that got me hooked to join .. so thank you to all those that have and are posting here .. I've got Klipsch Quartets from 92 and are very interested in following a similar path to the Fortes ...

[iaRIVR]

Hi All - I joined just to comment on this thread! Really interesting work and thank you for sharing. Most of my info is from watching the klipsch forums and working on my forte IIs.

1) The bracing looks fantastic. I have seen most people running 2-3 braces across the middle of the speaker, this method looks not only much cleaner but easier.

2) The Titanium mids were seen as a potential upgrade for the Forte I & II, but it seemed about 50% yanked them out right away because they were louder and it killed the balance. Could the Forte III crossover be used as the basis for a redesigned Forte I & II crossover to use Ti mids? There was a bandpass filter made but I don't think it was quite right. A lotta folks over on the klipsch forums might be interested in that mod...

3) Last one - I was considering replacing factor foam with acoustic panels or similar but understood that most folks stopped above the woofer rather than bringing the foam all the way down the side. The upper 2/3-3/4 or so. Maybe wanted to kill the reflections for the tweeter and mid but let the bass resonate? Not remembering exactly. Looks like you did the full length of the cabinet, any thoughts on stopping above the woofer?

[Tyson]

Hi All - I joined just to comment on this thread! Really interesting work and thank you for sharing. Most of my info is from watching the klipsch forums and working on my forte IIs.

1) The bracing looks fantastic. I have seen most people running 2-3 braces across the middle of the speaker, this method looks not only much cleaner but easier.

2) The Titanium mids were seen as a potential upgrade for the Forte I & II, but it seemed about 50% yanked them out right away because they were louder and it killed the balance. Could the Forte III crossover be used as the basis for a redesigned Forte I & II crossover to use Ti mids? There was a bandpass filter made but I don't think it was quite right. A lotta folks over on the klipsch forums might be interested in that mod...

3) Last one - I was considering replacing factor foam with acoustic panels or similar but understood that most folks stopped above the woofer rather than bringing the foam all the way down the side. The upper 2/3-3/4 or so. Maybe wanted to kill the reflections for the tweeter and mid but let the bass resonate? Not remembering exactly. Looks like you did the full length of the cabinet, any thoughts on stopping above the woofer?

If you're going to brace the Forte's, then you definitely want to use Norez as well.  That will give you the stiffest and most inert cabinet possible.  Which, IME is what you want.  On the other hand, if you want the cabinet to vibrate then don't brace it or use Norez because that would be counter to allowing the cabinet to resonate.  But in my experience, nothing good comes from a resonating cabinet. 

The Forte II is different enough that you'd need to send it to Danny to get a new crossover designed for it.  The midrange drivers are fairly difficult to work with, but Danny's a wizard at this stuff.

[iaRIVR]

If you're going to brace the Forte's, then you definitely want to use Norez as well.  That will give you the stiffest and most inert cabinet possible.  Which, IME is what you want.  On the other hand, if you want the cabinet to vibrate then don't brace it or use Norez because that would be counter to allowing the cabinet to resonate.  But in my experience, nothing good comes from a resonating cabinet. 

The Forte II is different enough that you'd need to send it to Danny to get a new crossover designed for it.  The midrange drivers are fairly difficult to work with, but Danny's a wizard at this stuff.

I need to get a few more posts before I can search - if this too off topic there might be a better thread.

My understanding is as stiff as you can get without taking too much away from the original volume. I will definitely look into the Norez. I have also been considering component upgrades, tweeter resistor and air core inductors primarily. I have sonicaps now, I did see an interesting post about adding bypass caps to those. New gasket material for the drivers. So many options!

Makes complete sense about the crossover, the Forte III in the pic looks significantly more complex than the Forte II.

[emailtim]

Next we measure!  Here's a picture of the setup.  Danny will post the graphs later, once we have the curves for both the old crossover and the new crossover.  For now, here's what the process looks like:

That jack is cheating !!!

[maddog07]

I saw earlier in this thread... where somebody was talking about having Danny design a xover for a Chorus II.  I have a vintage pair of Chorus II's myself.  And I have them completely disassembled right now.  The stock xover caps have been replaced with Sonicaps(as recommended by Crites), but I was going to brace and damp the cabinet before I put everything back together.  If Danny has a xover for the Chorus II... I'd be very interested as well - especially if the work is already done and I don't have to get the speakers in Danny's possession - they are huge & heavy = $$$ shipping.  Probably even cost prohibitive to ship.  I talked to Al Klappenberger about a year ago, and at the time, he said he had not done any work on xovers for Chorus'.

[Tyson]

Not sure about the Chorus II.  How close are you to Texas?   A drive might be in order

[emailtim]

I saw earlier in this thread... where somebody was talking about having Danny design a xover for a Chorus II.  I have a vintage pair of Chorus II's myself.  And I have them completely disassembled right now.  The stock xover caps have been replaced with Sonicaps(as recommended by Crites), but I was going to brace and damp the cabinet before I put everything back together.  If Danny has a xover for the Chorus II... I'd be very interested as well - especially if the work is already done and I don't have to get the speakers in Danny's possession - they are huge & heavy = $$$ shipping.  Probably even cost prohibitive to ship.  I talked to Al Klappenberger about a year ago, and at the time, he said he had not done any work on xovers for Chorus'.

Loved my Chorus II's.  Often regret selling them.  Hope you can work something out with Danny for your rebuild.

[Roy Boy]

I saw earlier in this thread... where somebody was talking about having Danny design a xover for a Chorus II.  I have a vintage pair of Chorus II's myself.  And I have them completely disassembled right now.  The stock xover caps have been replaced with Sonicaps(as recommended by Crites), but I was going to brace and damp the cabinet before I put everything back together.  If Danny has a xover for the Chorus II... I'd be very interested as well - especially if the work is already done and I don't have to get the speakers in Danny's possession - they are huge & heavy = $$$ shipping.  Probably even cost prohibitive to ship.  I talked to Al Klappenberger about a year ago, and at the time, he said he had not done any work on xovers for Chorus'.

That was me. I have not gotten over to Danny to him measure my Chorus II...I live in Dallas. I did take several steps to upgrade my Chorus II's based on this thread...
   1)Braced the cabinet
    2) Installed No Rez to damp the cabinet
    3) added dynamat-like damping to the drivers (mid lens, woofer and passive
    4) Swapped out the OEM tweeter and lens for Dave's LMAHL lens and DE10 driver
    5) upgraded OEM crossover with upgrade kit from Crites

I am quite pleased with the results. I have a pair of Seaton Submersive subs that I bring in under the Chorus IIs (they run full range) using a DBX PA-II Drive rack. I have been ripping my vinyl using am RME ADI-2 Pro ADC at 24-352....I ripped an original Heart - Dreamboat Annie album. Streamed the rip of  "Crazy on You" back from my Lumin A1 at around 105db...It was crazy good. There was dancing and much air guitar going on in the house...

 

[Hobbsmeerkat]

I did something similar to my dads 90s Technics 3-ways. It still needs bracing, but I haven't had the opportunity to pick up the tool I need from my mother's places to cut them, but using the pseudo-norez on the walls and some dynamat on the mid and bass woofers really helped to tighten up the quality in those ranges, esp at higher volumes. The eventual bracing will only help things further.

[Josh Mo]

Reporting back after about 6 months. The upgrade kit from GR Research and additional bracing has taken these good value speakers and really improved them all around. 1khz spike didnt both me too bad before, but now that its been squashed the speaker is much more pleasant to listen to. Speakers are much less boxy sounding, more natural, kicked up level of detail, etc. I was worried that the natural sound and tuning of this classic speaker might be altered, but it was only enhanced.

Appreciate Tylers willingness to bring the speakers down for analysis and Danny's work / releasing offering the upgrades to the community. Thanks guys - I picture many many more years of enhanced enjoyment from these speakers.

[NickMimi]

That is great to hear, thank you for the update. I have read every word in this thread since i am And have been a Klipsch Fanboy for close to 2 decades now!  Another idea in the hopper for a future purchase.