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Loose back panels on Heresy II's?


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So the back panels on my Heresy II's don't seem to be very tight. I can push back and forth on one of the corners of each speaker and there is some play. During certain songs with heavier bass you can hear the back panel rattle from the vibration. I don't see a way to tighten them...the only screws I see are for the crossovers...has anyone else had this issue before? Solutions? Hoping this is an easy fix. Any help would be greatly appreciated. Thanks.

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Never seen that before... My HIIs are still solid. You can get some epoxy resin, thinned with acetone, and put along the seams from the inside (take woofer out for access). The epoxy will soak in and seal everything together.

 

Bruce

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It won't fall out, as the backs fit into a rabbet (I think that's the correct term). The epoxy gets thinned so it is like water, capillary action will get it into the joint space. Once it sets, it should be better than new with no visible sign of repair. Once I'm on my desktop pc I'll find the link for the product. I will be using some on the old pair of LaScalas I am working on. The old glue is not holding very well, and while working on them I figured I should make sure they aren't just held together with ring nails.

 

Bruce

 

EDIT: Here's the link... you can get smaller quantities.

 

https://www.amazon.com/TotalBoat-Penetrating-Epoxy-Pint/dp/B0141F71II/ref=sr_1_1?ie=UTF8&qid=1465765805&sr=8-1&keywords=totalboat+penetrating+epoxy

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By way of background:  The Heresy and Cornwall in the traditional versions had a panel on the back which was screwed in place.  The drivers were mounted to the back (interior side) of the front board.  Therefore the removable back was needed to allow the drivers to be screwed in.  Likewise for the crossover board.

 

In the newer designs (HII, CWII, Forte, etc.) the back panel was glued in place and the drivers screwed into the front side (exterior) of the front board.  The was some thought that flush mounting the drivers eliminated diffraction issues arising from the drivers radiating though the cut out in the front board -- it looks more tidy too.  Oh, and the crossover circuitry was placed on the terminal cup and didn't have to be screwed to the interior IIRC.

 

You can see how these all went hand-in-hand.  (There were likely gripes that this re-design, use of MDF which doesn't take screws well, and plastic horns, was value engineering which dumbed down the whole system  OTOH, Klipsch has to meet price points.  You do that or go out of business.)

 

This all means that in the new design the interior can only be accessed by taking out the woofer and reaching in there.

 

I'd suggest you do that and apply adhesive (construction adhesive) to the seam between the back board and the cabinet.  It should not be too difficult when the unit is on its back.  You will probably have to disconnect the wires to the woofer at the crossover.  Make notes of what goes where, of course.

 

I'd think that dribbling something into a crack on the outside is very much a half measure compare to doing a good job on the interior.

 

While you are doing all this it might be a good idea to apply the adhesive to the seam between the front board and the cabinet and even the edges of side boards to top and bottom.  If the seal at the back failed these might be compromised too.  A little tricky but will give you some peace of mind.

 

Overall, the bass unit will only work as intended when the box is air tight.  If you've got a corner which is moving, you probably have lost the necessary seal.

 

WMcD 

 

 

 

 

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34 minutes ago, WMcD said:

 

 

I'd suggest you do that and apply adhesive (construction adhesive) to the seam between the back board and the cabinet.  It should not be too difficult when the unit is on its back.  You will probably have to disconnect the wires to the woofer at the crossover.  Make notes of what goes where, of course.

 

I'd think that dribbling something into a crack on the outside is very much a half measure compare to doing a good job on the ...

 

WMcD 

 

 

 

 

 

I am not suggesting 'dribbling' something on the outside of the cabinet at all! Remove the woofer to apply the epoxy to the joint. This is basically the same as the W.E.S.T. System epoxy, the Wood Epoxy Saturation Technique, where the wood and joint are saturated with a very thin epoxy, bonding/fusing the pieces together. They will be far more sealed than you can imagine, and far, far neater than applying construction adhesive to the joint.

 

Bruce

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Sorry, Bruce, you're absolutely correct to call me out.  You were talking about working from the inside. Further, I should not have been smarmy using the term "dribble."  My apologies.

 

I still have some lack of faith in capillary action.  Though not in your advice and expertise.  Smile.

 

WMcD

 

 

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1 hour ago, WMcD said:

By way of background:  The Heresy and Cornwall in the traditional versions had a panel on the back which was screwed in place.  The drivers were mounted to the back (interior side) of the front board.  Therefore the removable back was needed to allow the drivers to be screwed in.  Likewise for the crossover board.

 

In the newer designs (HII, CWII, Forte, etc.) the back panel was glued in place and the drivers screwed into the front side (exterior) of the front board.  The was some thought that flush mounting the drivers eliminated diffraction issues arising from the drivers radiating though the cut out in the front board -- it looks more tidy too.  Oh, and the crossover circuitry was placed on the terminal cup and didn't have to be screwed to the interior IIRC.

 

You can see how these all went hand-in-hand.  (There were likely gripes that this re-design, use of MDF which doesn't take screws well, and plastic horns, was value engineering which dumbed down the whole system  OTOH, Klipsch has to meet price points.  You do that or go out of business.)

 

This all means that in the new design the interior can only be accessed by taking out the woofer and reaching in there.

 

I'd suggest you do that and apply adhesive (construction adhesive) to the seam between the back board and the cabinet.  It should not be too difficult when the unit is on its back.  You will probably have to disconnect the wires to the woofer at the crossover.  Make notes of what goes where, of course.

 

I'd think that dribbling something into a crack on the outside is very much a half measure compare to doing a good job on the interior.

 

While you are doing all this it might be a good idea to apply the adhesive to the seam between the front board and the cabinet and even the edges of side boards to top and bottom.  If the seal at the back failed these might be compromised too.  A little tricky but will give you some peace of mind.

 

Overall, the bass unit will only work as intended when the box is air tight.  If you've got a corner which is moving, you probably have lost the necessary seal.

 

WMcD 

 

 

 

 

Really appreciate the in depth reply! So no screwing the panel in anywhere? I'll have to dig into them this weekend and take a look inside. Also, I compared the bass with the panel loose and with it tight (my hand holding it in) very very noticeable difference. More punchy when air is trying to escape. Dare I say the bass sounds better? In my opinion of course and without the rattle of the panel...leads to my next question. Why aren't the Heresy's ported? Maybe that is a stupid question but hey, I'm new to this!

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No offense taken, William. One of the other members on here used the technique to get some laminations glued back together on his LaScalas (IIRC), and the process is used a lot in repairing (or avoiding a huge repair...) in the boating industry, as well as fixing up rot on window frames, etc. I will be trying it on the old LS pair I have, to saturate all the joints, as the glue has dried out and isn't holding things together very well.

 

NB, there are no ports on these Heresy models because that is how they were designed. The woofer specs and cabinet size won't work well for porting. However, if you look up the Klipsch Tangent 400, it uses the exact same parts as a Heresy II, but the cabinet is larger and ported. Lower end is much better, too. The Tangents were built to market through the military exchanges, with a less durable cabinet, but they are a great value. If your cabinets were in terrible shape, the better thing would be to replicate the T400 box and move your parts into them. But I digress...

 

Bruce

 

http://www.klipsch.com/products/tangent-400

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Thanks Bruce.  I was worried.  I'll say one more mea culpa and let it go at that.

 

I agree with Bruce.  If you want a ported speaker, the box must be bigger.  There is a family of Heresy, Industrial, Ported HIP which seem to have a box smaller than the Tangent, but they don't go as low but have a higher SPL output, a bit.  Overall, there are no free lunches.

 

You might well be getting some additional output at some bass freqs with the leaky seam.  It is probably because the effective spring of the box is no longer controlling the excursion of the bass driver, as it was designed.  PWK designed the system to give low distortion in a small size.  He was the master.

 

Rethinking my advice on construction adhesive.  You're probably better off trying a very fluid adhesive first and let capillary action move it into the gaps.  I was thinking super-glue, though not the gel of course. You could then go to construction adhesive or yellow glue if warranted.  Once the latter two are in there, you can't go back to something very liquid, or anything.

 

I'd stay away from the original Gorilla Glue.  It has the consistency of honey and as sticky and probably will not seep into a crack.  In curing it foams like shaving cream. Useful in some applications though not here, I'd think.

 

I haven't done any woodworking lately.  But for the record, I really like yellow glue like Tite-bond I, II, or III.  I've used a finger to mush it into gaps.  It is water based for easy clean up and non-toxic. 

 

Post photos please.  We all love to see them.

 

WMcD

 

 

 

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I'm not sure what kind of glue/adhesive they used on the later heresies, but couldn't he just go with the klf method? Remove drivers and crossover, use a heat gun on the edges of the back panel, carefully pry the back panel off, clean old adhesive, then use liquid nails to glue it back together. Clean up excess in the back, from the inside, use your finger to create a corner seal with the excess inside from the side panels to the back panel. Lay it on its front with some weights on the panel and let it dry. Fyi, liquid nails takes 7 days to cure, so no music until 7 days.

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On 8/4/2016 at 8:50 PM, NowBlasting said:

I'll have to dig into them this weekend and take a look inside.

Good idea, I would remove drivers and seal ANY joint that can be reached, what you seal with is the question. Something that would put a nice bead and seal any air leaks, your choice. It will make a big difference. Groomlake (marshal) talked about this all the time and said it's pretty common and being air tight, or close makes a difference easily heard.

 

Especially in your case that's it loose enough to hear vibrating, can't hurt that's for sure and it would be cheap. :emotion-21:

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7 hours ago, dtr20 said:

I'm not sure what kind of glue/adhesive they used on the later heresies, but couldn't he just go with the klf method? Remove drivers and crossover, use a heat gun on the edges of the back panel, carefully pry the back panel off, clean old adhesive, then use liquid nails to glue it back together. Clean up excess in the back, from the inside, use your finger to create a corner seal with the excess inside from the side panels to the back panel. Lay it on its front with some weights on the panel and let it dry. Fyi, liquid nails takes 7 days to cure, so no music until 7 days.

 

From what I have been told, the HII cabinets have a groove (rabbet) on the top, bottom ans sides, that the back and front fit into. Once assembled with glue, they are in there for good. It's been a long time since I've pulled a woofer off mine to see the inside, though.

 

Bruce

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