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Specific questions about upgrading Forte I


Frame7

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Hi,

 

I have been eyeing the Crites Cornscalas for some time now and have been researching and considering the various versions that are available as well as a number of Klipsch community user tweaks. This past weekend I picked up a pair of (beautiful, excellent condition) Forte I’s at a garage sale for $165. Model #864....... I am going to hold off on the Cornscalas and spend a little time with the Fortes. At $165 I don’t mind putting in a few additional bucks to make them sing. 
 

I have a few questions.

 

1) In refurbishing or upgrading a pair of older Fortes has anyone completely replaced the mid range driver with a non-Klipsch driver?

 

2) In the Cornscala world the ALK crossovers seem to be very popular and in some circles are considered to be an improvement over the Crites crossovers. Does anyone have experience with ALK’s crossover for Forte I?

 

3) I have read a lot about replacing diaphragms and refurbishing/upgrading/replacing crossovers as well as adding bracing, etc.... For a 30 yr old pair of Forte’s is there anything else I should consider or be aware of?

 

4) Beyond rotating the woofer and passive radiator 180 degrees is there anything else I could or should do with the woofers and or radiators? Any benefit in replacing them with new parts?

 

Thanks in advance!

Edited by Frame7
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lots of threads on forte/chorus upgrades on here, just do a search for them.  im sure others will chime in with more details, but to answer your last questions on woofer/passives,  some like to dampen the baskets with something like dynamat or roof flashing sold at home depot etc.  you can also tune the passives a little lower by adding 1-2oz of weight to the center of the cone on the back side, some washers with rubber cement or epoxy, or just some tape for temporary testing to see if you like it.  if they are in good working order, factory woofers are as good or better than the replacement options.  

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make sure the cabinets are are airtight. replace all the gaskets, don't forget the one on the terminal cup and the two on the mid horn (at the throat to driver interface) yours will be hard by now Bob Crites will sell you a fresh set.

The weight on the passive can be up to 2.5 ounces (not more) use large flat steel washers to build up the desired weight and bond them together with four very small (to minimize extra weight) dabs of five minute epoxy and mount the whole weight with three or four small dabs of the same epoxy. This will hold them securely in place and it will make them easy to remove should you ever want to do so at a later date to return them to stock tuning.

Dynamat or hushmat on the woofer and passive baskets is a good idea as it reduces ringing. a layer of constrained layer damping on the mid and tweeter pole pieces topped by a layer of F-11 Acoustical felt will transform your horn drivers. make sure not to felt felt in the voice coil gap and don't let the felt touch the diaphragm. Three small dabs of craft glue like Aleene's tacky glue will hold the felt in place, in this application the right adhesive in a minimal quantity is best.

I like to twist my lead wire pairs to minimize pick up of stray fields.

Below are some photos of my brace work in a Quartet which is the same as a Forte only three inches shorter. They should give yo a good idea graces are on edge and are 3/4"x2" this yields maximum stiffness with minimum material. Stringers can be fir 1x2 which is really 3/4"x1.5" but if yo like you can use all ply material. You can damp all you want above the woofer and some on the bottom of the cabinet but keep the area between the woofer and the passive free of damping that area must be free to fully resonate so the two can effectively couple.

   After you finish your Forte keep your eyes open for a set of Chorus ll and do the same to them. If you want to get into flea size SET or SEP amps then find a set of Cornwall 2 and work on them they are designed for lower power amps where the chorus with its pro woofer are built for power. Hope this helps. You could also take a good hard look at the Bob Ctites Cornscala "D".

Quartet rebuild 021.jpg

Quartet rebuild 020.jpg

Quartet rebuild 017.jpg

Quartet rebuild 016.jpg

Quartet rebuild 011.jpg

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