Sealing Bass Bin of Khorn

[garyd9]

Q-man,

I like the idea of a corner board after I permanently fasten the mdf to the plasterboard. I think that it would improve the possibility of a good seal between the insulation on the tail board and the wall. I am unsure of the physics of the problem, but I am assuming that we are trying to prevent the escape of the presure waves as they travel down the exponential horn. I still want the insulation to seal the tail board to the corner board/wall.

Gary

[playntheblues]

Gary, thank you. I think I have finally got it.

[ssh]

HDBRbuilder,

Months ago, I turned your suggestions into a much improved seal, & sound.

I just thought I'd echo.

SSH

[jhawk92]

Lynnm-

Good to hear that your pipe insulation has helped. I have the same stuff in my garage and will get it installed after I finish up my version of the "semi-false corner" for one speaker; a sheet of 3/4 MDF mounted so that I have a full corner to snug the speaker into, per Artto's and Q's advice.

Gary-

Great pics, especially of the bottom of the tail board. I had thought about cutting two separate pieces of insulation to cover the two different outlines, but seeing your solution, I think I'll go with that. I also hadn't thought about staples, but that makes sense. I'm glad my thoughts to get extra insulation (3/4" this time) to seal the top of the bass bin were right on, since I see you did that in your pics as well. Painting of the MDF will be done in a day or so, and then I'll mount to the wall and be ready to go.

HDBR-

As mentioned earlier, don't fret if you hear your voice echo in here. I've used much of your advice and get better sound for it. I think next I'll put down the MDF "floor" for the K-horns, but I need to go in baby steps to keep CINC-house happy. Could you get more of the grippers and stack 2-3 tall and keep the gliders installed? Just wondering since I doubt this will be the last house I'm in (seem to move every 3 years) and the gliders sure help move these beasts.

Also, good info on damping the K-400 horn. I don't seem to get much ringing with it right now, but I'll see how it does after I seal the corners. Have you had much experience with the composit K-401 horn in comparison? I was thinking about just swapping out the metal horns and installing the new ones. I know other folks have them, and was wondering what you thought. When I tap the horns as they are now, there is no ringing, so I may be good to go. I seem to remember tightening up all the screws in the top cabinet when I brought them home, since one was missing one of the screws that mount the motorboard to the cabinet itself.

[hoggy]

Thank very much all to your replies. What great pics and info. I have sealed my Khorns but only temporarily until I get all the sealing worked out plus plywood/or MDF on the carpet. Thanks all who have posted. This has answered all my questions and am sure has helped many to accomplish getting the best of their Khorns. Great posts guys,

Thx again

hoggy

[Rudy81]

Boy am I glad I found this thread. Thanks also to HDBRbuilder for his contributions.

A little over a week ago I had a chance to audition a pair of the new Palladiums. I was blown away by the bass performance. I thought my Khorns could stand along with them, except in the bass department. The Palladium bass was precise, tight and deep. Granted, I don't have 400 watt monoblocks to each speaker, but it started me thinking. Why do my Khorns not have the kind of bass they are known for, at least not in my room? I have 125 watt Parasound HALO amps and the complete HALO line for the best sound I can afford. I also have the CT125 tweeters and universal ALK's.

I had built some very dense and heavy false corners, sealed the bass bin with pipe insulation and I know the drivers are working and there are no air leaks.

In researching the Khorns and bass response, I came upon this thread. When I built the corners, I put carpeting on top of the 3/4" plywood base. So, tonight I ran to Walmart after Thanksgiving dinner and got four boxes of 1 1/2" grippers. Quickly tore out the carpeting on the corners, removed the metal glides and installed the grippers. I did have a hell of a time moving the bass bins back into the corners, those grippers GRIP. I guess it is as close to mass coupling the bin as you can get without spikes.

The result is a noticeable increase in bass response at least it seems that way. I know because the floor was vibrating even at low volumes and it wasn't like that before unless I was cranking it loud. I was not able to really crank it up since the family was downstairs watching TV. So far, I am really impressed with the simple change. Tomorrow I will go up and give a listen at reference levels. The gripper idea might just be the ticket. You can see the false corners here http://www.prontoweb.com/klipsch_HT.htm

Happy Thanksgiving!

[Rudy81]

I just confirmed my suspicion that I was getting better, more defined and lower performance from my Khorns after the gripper addition and removal of the carpeting.

I originally knew my Khorns could not reach really low when listening to Billy Cobham's 'Slow Body Poppin'. That track has some very low, subtle drums that I could only hear when I added my sub to 2CH listening....something I don't like to do. I feel my SVS is great for movies, but not precise enough for critical listening in 2CH.

Today, I found I can now hear those low frequencies clearly without my sub in play. As a matter of fact, I could barely tell the difference with the sub on. Previously, it was obvious the sub was on. I am very thrilled with the improvement and only wish I could borrow somebody's Palladiums, move them into my room and compare them with 20 year old Khorns.

Thanks for the cheap improvement. That's the second big lesson I learned about Khorns. They MUST be properly sealed to get good bass....and they must be on a solid surface, mass coupled or "gripped" to get great bass.

[IndyKlipschFan]

wow.... Thats a very very nice theater too!

[artto]

#1 Why do my Khorns not have the kind of bass they are known for, at least not in my room?

#2 I had built some very dense and heavy false corners, sealed the bass bin with pipe insulation and I know the drivers are working and there are no air leaks.

In researching the Khorns and bass response, I came upon this thread. When I built the corners, I put carpeting on top of the 3/4" plywood base. So, tonight I ran to Walmart after Thanksgiving dinner and got four boxes of 1 1/2" grippers. Quickly tore out the carpeting on the corners, removed the metal glides and installed the grippers. I did have a hell of a time moving the bass bins back into the corners, those grippers GRIP.

#3 I guess it is as close to mass coupling the bin as you can get without spikes.

#1 You hit it on the head. "In my room". The Khorn is literally coupled to the room in the bass department. The room is part of the bass speaker and will ultimately determine it's performance.

#2 Same thing. False corners. Yes, you'll get most of what the Khorn has to offer (as well as some other benefits in less than optimum conditions). But if it's in false corners its not really coupled to the room as it was intended.

#3 If you want to mass load a Khorn the proper way to do it is not with spikes or grippers or whatever. A custom corner wall plate must be made so that the tail board can be structurally attached to it. The corner wall plate is also structurally connected to the wall. Or with the old decorator style units the whole Khorn can easily be installed "in-the-wall". In my system the Khorns are basically mass loaded to earth via the building foundation in the manner described. (It made more difference to the mid/treble than bass IMHO)

[Rudy81]

Getting maximum performance of my Khorns has been a long learning process. The room size is not too bad in terms of frequency problems, although I did have to treat the walls to tone down the many reflections. To properly seal the tailboard, I had to go to pipe insulation. Thick rubber gaskets did not do a sufficient job of sealing. I used a flashlight to see if any light leaked around the seals and with my original seals I could see light around the tailboard "leaking" into the front of the speakers. The pipe instulation worked very well.

I use false corners since I have windows in the way and not a complete corner. I found that I like being able to angle the top hat in to my sitting position, imaging was much better.

Now the grippers have helped again. Live and Learn! I also need to post some more recent theater pictures. It has evolved some of the past two years.

[LarryC]

I use false corners since I have windows in the way and not a complete corner. I found that I like being able to angle the top hat in to my sitting position, imaging was much better.

Do you have a pic handy?

[Rudy81]

You can see various pictures here http://www.prontoweb.com/klipsch_HT.htm

I need to post some more current shots. I have since completed the HT except for the changes I am making on the base of the false corners. I should be done tomorrow and will hopefully post some updates.

[Rudy81]

Here is a picture of the pipe seal around the tail board. I also added some wood to the cutouts at the bottom in order to totally seal against my false corners.

[Rudy81]

This is the new look of the false corners, carpet removed, grippers installed on bass bin bottom. I covered the bottom 3/4" plywood with stick on flooring.

[Rudy81]

This is as tight as I can get the seals in the corner. I use a flashlight in the very corner behind the tail board and look for light leaks arund the seals from the front. I figure no light leak, so air leak. I feel like I have a new set of Khorns after this cheap but very worthwhile mod. I am adding more up to date pictures of the HT in my web page.

[Groomlakearea51]

A proper seal is probably the most critical thing you can do for them. I even cut a new tailboard and a bottom section piece that isolates the bin from the floor to fully eliminate any leaks whatsoever on the pair I finished a couple months ago. In addition, I also isolated the bin from the top section. The results were as expected.

http://forums.klipsch.com/forums/p/109618/1105072.aspx#1105072

[Rudy81]

Very nice project. I think with my latest mod, I'm 95% there as far as bass response. Short of screwing the false corner to the bass bin, there is nothing else I can do. However, doing that would make it nearly impossible to flip the speaker back upright. My corners must weigh 70 or 80 pound each. The corners themselves are a bear to move around. With the speaker on top, it is very difficult to move. Heck, it was hell moving the speakers back into the corners now that they have 16 grippers on the bottom of the bass bin. Now, with 2CH music there is almost no difference with vs. without the sub. Only the lowest frequencies will reveal the sub to be on. I generally do not like to use the sub for 2CH litening. It is not nearly as dynamic and precise as I would like for critical listening. For movies, however, it is awesome.

[profsbg]

Curious whether you noticed any improvement by cutting the
additional piece of wood and sealing vertically all the way to the
floor as you have done. Most of the pipe insulation seal jobs I have
seen (mine included) simply follow the tailpiece to the floor. Since I
dont have baseboard, this does leave a gap.

[Rudy81]

I never did run any listening tests to see if that made any differance. But, I figure any non-sealed area has to reduce from the bass bin's potential.

[Arkytype]

HDBRBuilder (and other forum members) might confirm this but I seem to remember that you are supposed to remove the four metal "feet" from the bottom of all Klipsch loudspeakers. The "feet" were used at the factory only to allow sliding the loudspeakers on the factory floor to the next stage for painting, testing, boxing, et al.

By removing the "feet" you are effectively and efficiently coupling the box to the floor.

Lee