Heresy 3 Brace work...

moray james

Super Member
Here are some pictures of an excellent job my brother just did on a pair of H3 cabinets. The cabinets had an issue with loose baffles and thinned white glue was worked into all the seams to tighten them up prior to additional 3/4 strapping to seal and stiffen the baffles. All internal material is 3/4" Oak as it is rigid and will take up little volume in a retro job like this. Each panel has a vertical brace except for the rear baffle which had two braces due to the mid horn driver. There are two 3/4" square struts which tie the top and bottom the two sides and the front and back. There is also a brace between the mid horn driver and the back baffle not shown in these pictures. These cabinets are rock solid and any comparison to a stock hollow cabinet is simply a joke. I hope that the photo files are not too large to load. Best regards Moray James
 

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sounds good please post your findings and some pictures of what you decide to do. A simple block with some compressible rubber behind the mid horn driver makes for a very effective back panel damper and braces the horn as well at the same time easy cheap. Look forward to reading more. Best regards Moray James.
 
Good info Moray, thanks for the pic's. When I finally open up my stock HII for new caps or just replace the cross overs like I did the Cornwalls I will try the braces and the others mod's we talked about. Your advise on Crites CT-125 tweeters was spot ON too.. I love them :music:
Louis
 
Nice work

I am guessing that the newer Heresy's do not have a removable back cover. It would be difficult to remove the driver with that extensive bracing. But a sutible compromise could be made for older versions. I would love to see that work in detail.

Thanks for the post. I will experiment with this on my expermental pair of Heresys. This gives me a good idea of what will be needed to brace the cabinets.
 
Jessearias: the Heresy 3 has no removable baffles so all retro work can only be done through the driver openings. The older Heresy have a removable rear baffle. I would suggest that the easiest thing to do and for the very best results is to remove the front baffle on a Heresy or a Heresy 2 and install a new baffle, one on which all the drivers front mount. Remember that 3/4" strapping has been inserted on all panel to panel seams throughout the cabinet to increase stiffness and insure air tightness. The H3 is a very loose cabinet. Do not forget that the single most important brace in this cabinet is the on edge one which horizontally divides the front baffle in between the woofer and the mid horn. Further if I were doing this again I would install a similar cross baffle brace between the top of the mid horn and the tweeter horn. I hope that this is of interest. Best regards Moray James.
 
Here are some pictures of an excellent job my brother just did on a pair of H3 cabinets. The cabinets had an issue with loose baffles and thinned white glue was worked into all the seams to tighten them up prior to additional 3/4 strapping to seal and stiffen the baffles. All internal material is 3/4" Oak as it is rigid and will take up little volume in a retro job like this. Each panel has a vertical brace except for the rear baffle which had two braces due to the mid horn driver. There are two 3/4" square struts which tie the top and bottom the two sides and the front and back. There is also a brace between the mid horn driver and the back baffle not shown in these pictures. These cabinets are rock solid and any comparison to a stock hollow cabinet is simply a joke. I hope that the photo files are not too large to load. Best regards Moray James



THANKS for posting these photos. I'm sure many AKers will find these very useful. Were the strips cut for a force fit or did they just slip in? If the front baffle were removed on this speaker do you think the box might just fold up?
What was the improvement in the sound?
 
The H3 cabinet is one of those wrap around designs where once assembled the baffles are supposed to be securely locked into a channel and glued into place forever. This only works if you make sure the glue joints are not dry. The H3 were very poorly built and the baffles front and back were dry and loose. A combination of thinned down white glue and strapping was used first to wet the original joints and then full strength white glue was used to install corner strapping along all the seams to secure all the panels then after that the brace work was installed.
You want to make braces easy to install or you will be making yourself multiple nightmares. Braces should be easy to install by hand use yellow carpenters glue which grabs fast and which fills gaps well. Remember that wood absorbs water and if things get damp it will expand. I have seen cabinets ruined as a result of braces being hammered into place when dry then later expanding to the point of the destruction of the cabinet. So don't force anything.
Any cabinet vibration is unwanted noise it is distortion. If you find that by bracing a cabinet you have lost bass you have in fact not lost any bass other than low frequency noise your box was making. Box talk is not part of the music. A speaker cabinet is not an instrument. It is a volume of air and ideally offers nothing more than that. I hope that this helps. Best regards Moray James.
 
Wishing to clarify a point here....you're suggesting to brace the midrange driver physically to a newly installed piece of strapping and buffer it with some makeshift rubber, correct? Sounds intriguing and would not thought to do this.

Asking because I'm redo'ing a set of original Heresy cabinets. I just didn't realize that the driver should be quite as "isolated", if that's the proper description.

Bought 1" x 2" oak to use. Probably won't do quite as extensive bracing as above, but will borrow heavily
 
well if you got lost with "it is a volume of air" then I don't think there is much more to say past telling you that volume of air presents a critical load to the loudspeaker which is what tunes it. Larger volume tunes lower smaller volume tunes higher.
 
Moray do you still own your "Modded" Heresy III's? IIRC you braced them somewhat like you did the KLF-20 that needed to be repaired.
Louis
 
Moray do you still own your "Modded" Heresy III's? IIRC you braced them somewhat like you did the KLF-20 that needed to be repaired.
Louis

This is all white oak and there is a 3/4x3/4 baton on every seam inside of the cabinet they are very rigid now. good to hear from you Louis hope you are doing well and that you are getting out on the bike this summer.
H3 Brace Work.jpg
 
No motorcycles for me right now Moray I hurt my right rotator cup "again" several months ago . Thanks for the pic showing the braces as it's about time to to re-cap or replace the cross overs in my Heresy II (1989) like we did my (1979) Cornwalls with Bob Crites new networks.... I still have the CT-125 tweeters I got from you for my Cornwalls........ they still sound awesome to me. :) I read Bob has a different driver for the CT-125 have listen to one them yet?
 
Hey Louis sorry to hear about the injury, that stuff is so very slow to heal and getting older does not help neither does repeat injury that will make it all the more slow to heal properly. Please be careful heal yourself well this time.
Stick with the oil filled motor run caps. The CT125 is a fine phenolic driver and it is well extended and I find very smooth yet suffers no lack of detail whatsoever. I have not heard Bob's new drop in CT120 driver but the reports are glowing so far it seems a qualified hit. I hope you will be out on the bike next summer. Take care my friend your health is so very important. Best regards moray james.
 
I disconnected the mid inside my Heresys and put an Altec 811 horn on top with some 808 drivers, very clan and detailed.
They are from the 80's I believe.
have you experimented with aligning the Altec diaphragm with the Klipsch woofer? Also have you listened to the Altec 811b in a vertical orientation rather than horizontal? Good for you and happy experimenting.
 
have you experimented with aligning the Altec diaphragm with the Klipsch woofer? Also have you listened to the Altec 811b in a vertical orientation rather than horizontal? Good for you and happy experimenting.
I'm finishing my wood shop up inside so I can get in there and do some work.
I plan on doing some new cabinets for the Heresy's and horns, I will be doing the fine tuning and aligning of the horn and driver then.
 
I'm finishing my wood shop up inside so I can get in there and do some work.
I plan on doing some new cabinets for the Heresy's and horns, I will be doing the fine tuning and aligning of the horn and driver then.
Take pics when you do it. I wanna see them when their done. Are you going to use the same crossover too. or change that out as well?
 
I'm finishing my wood shop up inside so I can get in there and do some work.
I plan on doing some new cabinets for the Heresy's and horns, I will be doing the fine tuning and aligning of the horn and driver then.

I experimented with the Peavey CH1 horn on the Heresy ll as a two way but that is rather larger compared to the 811b. The 811b likes to cross on the higher side of where the Heresy crosses to the horn many folks like it crossing around 1100 Hz.. You could do that easy with a CH3/4 network from Klipsch.
 
Take pics when you do it. I wanna see them when their done. Are you going to use the same crossover too. or change that out as well?
I will use the standard crossover for now, and then I will look into different crossovers.
I have to finish getting all my walls insulated and covered in the shop first.
 
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