Heresy question.

[arfz28]

I took the backs off my set of heresys to see what drivers were in them and to go ahead and check all conections on the crossovers just really doing a check over. Speakers have no problems but what I notice right away after taking off the back panel was that there is no seal around it. The heresy is in a sealed box so I was wondering if anybody has put some wheatherstriping on the back panel before and if so has it improved the sound? It seems to me that there is no way without a seal that there aint some small air leaks. So has anybody sealed the rear panel on their heresys and found and improvement, seems like this might be a cheep tweek. Oh these are 84 models

[Hardhead]

I've done it and didn't notice any change. If the backs are screwed tight to the cabinet, air gaps shouldn't be a problem; that's a big "if," though, because sometimes the wood of the cabinets can shrink or expand with too much or too little humidity and let the screws loosen a bit.

If it will make you feel better about your speakers, do it; it won't hurt anything if you do it right. Be sure to use narrow weather stripping so the screws don't have to go through it. Also, make the weather stripping as thin as you can find, since any gaps would be VERY small.

[Groomlakearea51]

It works well on H-I cabinets due to the gaps on the braces, etc. If you want to seal the cabinets (after all they are an acoustic suspension system) you should fill in the gaps on the braces that secure the motor board. You can use a number of different types of material, but an effective method is to use woodworkers glue. I recommend the glue because it is somewhat flexible when it dries and does not affect the normal expansion and contraction of the brace gaps. You should also run a bead along where the motor board braces contact the sides and top panels. Same thing on the rear braces. Make sure that there are no gaps. On the rear panel, you can use speaker gasket closed cell foam stripping (1/8" thick). Make sure the ends "touch" to eliminate gaps. A final "attention to detail" issue is the screw holes on the woofer frame. If you look at those holes you can see that there is a cutout on the gasket. This results in quite a significant "leak". I usually will use some GE black silicone and put a bead about 1" along the edge where that gape can be seen, and a small amount over the screw head. It's removable later if you change woofers. You should let that (and the glue) dry for at least 24 hours before securing the rear panels.

Generally once the box is "tight" there will be some improvement in the bass. After all the cabinet has dried out for 23 years...

Hope that helps.

[arfz28]

Groomlakearea51. I understand everything you are telling me to do but do I need to remove the woofers to put the silicone on or just go around and over the top of the screws with the silicone without removing the woofers. I really need to take the backs off and take a look at the woofers but heck I figured its just as easy to ask you. I probably wont work on this project tell the weekend anyway but I really think it wont hurt a thing sealing everything up like you are talking about.

[Groomlakearea51]

Arfz28: Just go around the edge about 1" on either side of the screw hole position, and a dab on the screws to block the edges of the four holes through which the screws pass.

The whole "process" of sealing, should not take more than about 30 minutes of actual work. Overall, takes about an hour or two. Here's the procedure:

Remove backs - Carefully, you will need to unscrew the crossover leads at terminal block. Set rear panels to side.

Lay the cabinets face down. Using woodworkers glue (or silicone, or "paintable" caulking, etc.) seal the braces, brace gaps, and edges where braces contact motor board. Allow to dry enough so it wont sag/ run, etc.

Using silicone seal the woofer screw holes. Allow to dry, etc.

Stand cabinets vertical, seal braces along lower rear braces and along edge/ joint where panels connect. Allow to dry.

Repeat with cabinet on each side, then on top, etc.

Apply the closed cell foam gasket material to rear panel edges. Using a nail, or a screw, make the screw holes through the gasket material (I use a leather punch... makes a neat hole).

Set cabinets and panels aside to completely dry for 24 hours.

At this time, dependent upon the age, you might want to recap the crossovers (E-2's I believe), or send them to someone to be recapped. They are likely dried out and that will affect the sound. There are a number of "recap" folks on the forum if you are "soldering challenged"... BEC, DeanG, and others come to mind.

You might also want to loosen, clean and retighten the leads from the drivers to the crossovers. Oxidation can build up and cause weird intermittent problems that are difficult to isolate later.

Regardless of re-capping, after they are dry, re-assemble, making sure that the leads from the terminal block to the crossover are correctly installed + to + etc.

Take them apart on a Saturday morning, seal them and put them back together on a Sunday afternoon. "Hook-em-up" and you should be able to tell the difference. It may be slight, but it will be there. The most common observation is the bass seems to be "punchier" or more solid and defined rather than "lower".

If you are in the "experimenting mood", take a piece of foam rubber, about 3/4" - 1" thick, by say 12" wide and about 30" long, fold it in an upside down "U" and make a "dome" over the woofer from the floor of the cabinet.

This is what Klipsch basically did when they introduced the H-II. I have found that it helps improve the bass, especially when the Heresy's are used in a "bookshelf" application (...off the floor). In my case, floorspace is at a premium, and I've got kids, so the Heresy's are either up on the bookshelves, or otherwise up on top of other speakers, etc. "Stock" unsealed, un-foamed vs sealed, foamed..? Quite noticeable improvement. I did side by side tests repeatedly in various locations and the H-I "Mod-1" works very well.

As far as overall clarity, and sound quality, particularly in the midrange, really requires the caps to be done. This applies to all of the Heritage series if they are "old". I have a pair of Klipschorns that, in my opinion, sounded worse than a pair of Heresy-II's until I was able to have the crossovers recapped. Can be the difference between day and night, dependent upon age and cap condition.

Have fun and good luck. You can PM me or email me over the weekend if you need any assistance.