Page 1 of 5 123 ... LastLast
Results 1 to 15 of 67

Thread: Horn Dampening--811B

  1. #1
    Gary L
    Guest

    Horn Dampening--811B

    In my quest for the optimum performance from my speakers I keep hearing from many that the first thing is to dampen the 811B horns.
    I don't hear any ringing but I do listen in the nearfield and have some time to mess around.

    Lots of info but what I need to know is where do I concentrate the dampening on the horns? Does it go on the back side behind the baffel, on the front side part that protrudes out, both? What is best.
    Also I have heard alot about what to use but would like some advice from those who have found what works and is relatively easy to put on/get off.
    Do I mix some tar type concoction, by sticky backed material, spray undercoating or what?
    I do not wish to destroy my horns by cutting fins, nor do I want to destroy the looks of them by gooping up the exterior visible portion.
    Don't know if others feel this way but at times I like to remove the grills and watch the speakers work while I listen, usually when I am getting loud, just seems to add to the pleasure.

    Any help on this subject.

    Thank you

    Gary

  2. #2
    Member
    Join Date
    Apr 2006
    Location
    Portland, OR
    Posts
    30

    Dampen Horn

    Gary, I recently refurbished a pair of 19's. To dampen the 811's I used Evamastic, a sound vibration dampening material that comes in 32" x 54" sheets and is .079" thick. I believe it's used to reduce vibration for mechanical ducts. One sheet covers both horns. I purchased the material through McMaster-Carr for $22/sheet shipped. One side of the material sticks to the metal on the horn well enough but it seemed that if you wanted to remove it at a later date, it wouldn't destroy the horn. The material was easy to cut with a utility knife to the shape of the 811 and I applied the mastic to all external surfaces of the horn except where the flange meets the cabinet. There I used double sided weather tape. The results were that when I tapped on the horns prior to mastic it would ring like a bell. After application there was a dull thud and it sounded close to wood. It smoothed out the horn and was definitely worth the $22 and 2 hours of time.

  3. #3
    Senior Member edgewound's Avatar
    Join Date
    Jun 2005
    Location
    Southern California
    Posts
    2,776
    Another material you can use is Dynamat sheet. It's a sticky-back asphalt sheet loaded with mica for vibration damping. Clean all the surfaces with rubbing alcohol, then cover the inside bells of the outer horn, and the inner flare that lives in the cabinet. It focuses the upper mids and highs from the fatiguing ring that happens at around 1000hz.

    There's other brands of the sound deadening sheet, too...you can find a few different types at Parts Express:

    http://www.partsexpress.com/webpage....ectGroup_ID=37
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  4. #4
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    9,720
    Quote Originally Posted by Gary L
    In my quest for the optimum performance from my speakers I keep hearing from many that the first thing is to dampen the 811B horns.
    I don't hear any ringing but I do listen in the nearfield and have some time to mess around.
    That's because you listen to your music so loudly that your ears are already ringing!

    Sorry... I couldn't help myself. Many times there are "problems" with speakers that we filter out with our onboard computers. After fixing the problem your listening experience should be a bit more open and relaxed... the sound will be slightly more true. The improvement will be subtle but well worth it.


    Widget

  5. #5
    Gary L
    Guest
    Thanks for the links and advice on this. Do either of you have photos of the finished horn so I can see the resulting look?

    I have been considering useing the goo they sell for dipping plier handels in to renew the insulation but I am not quite sure of what properties the dampening material needs to have.
    A friend used Great Stuff, the insulation in a can for filling cracks and crevices. It looks like $hit but his horns do Thud now instead of ring and sound a bit less shrill then mine.
    Some have even mentioned that Rhino Coating stuff they spray as bed liner in PU trucks. I could get this done easy enough and it would look just fine if you think that would work.

    That's because you listen to your music so loudly that your ears are already ringing!
    Thanks Widget but you might be right!!

    Gary

  6. #6
    Senior Member edgewound's Avatar
    Join Date
    Jun 2005
    Location
    Southern California
    Posts
    2,776
    Hey Gary...
    I don't have any pics of a dampened Altec horn, but if you do it like I said in the previous post, you won't see it from the front. You said that you want something reversible and this solution is just that. Once you start spraying stuff on, it's a MUCH bigger chore to remove it if you choose to do so.

    Rhino Lining, etc, might work fine, but it's a bitch to cut and peel off, and is for the most part permanent....and pretty expensive. You can get the same type of bedlining material in a spray can at the auto parts store now...if that's what you want to do.

    I'd go with the Dynamat type stuff.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  7. #7
    Gary L
    Guest
    Think you are right Edgewound. I am sitting here right now with some brown paper cutting and fitting the pieces for patterns. Whats behind the baffle doesn't matter how it looks but up front I really want to keep them looking right.

    I am a bit of a Perfucktionist with this stuff so it takes me a while to get R done.

    Should have just built wood horns while I was building the cabs but thats yet another future project.

    Gary

  8. #8
    Member
    Join Date
    Apr 2006
    Location
    Portland, OR
    Posts
    30
    Gary before I decided to use mastic I did my due diligence on Altec Lansing unofficial site. They have more information if you look up past threads, however most of the cures are non-reversible. Sorry no pictures, but with the mastic in place it's really not noticeable and the dam horns "thunk" like wood. In addition I purchased new foam surrounds that go around the cabinet face at the outer edge of the horn. I purchased them from a nice couple in No. Carolina who do a remarkable job of replicating them [email protected]. for anyone who's interested. These look just like the originals and are highly recommended. $50 shipped for two of them. With the foam inserts in place all you can see is the front of the horn. I don't know about sound improvement although I've read here and at other sites that there are those who have notice a slight improvement. Good luck, Rob

  9. #9
    RE: Member when? subwoof's Avatar
    Join Date
    Aug 2003
    Location
    fingerlakes region, NY
    Posts
    1,899

    I hear ringin' in my ears

    Back in the 70's I worked afterschool at a dealership that had an outside contractor do undercoating on the jeeps and cargo vans they sold.

    The super-tough black plastic they sprayed on the bottom of door panels to prevent small stones from chipping the paint worked like a charm on a pile of 811B's we snagged from a local auditorium's remodeling project.

    It was better than the flakey stuff that always fell off the big multicells and it really killed that ring on the horns.

    We timed the ring on one horn after it was struck while hanging from a fishing line. 30+ seconds of ring sure made us decide to go to JBL...esp after we had to buy those expensive TEN WATT diaphrams over and over and over...



    sub

  10. #10
    Senior Member Baron030's Avatar
    Join Date
    Feb 2005
    Location
    Chicago, Illinois
    Posts
    431
    Hi Gary L
    I don't think the pliers dipping goop would be very effective.
    And you said it yourself, the "Great Stuff" looks like $hit.
    I'd recommend that you go with a "Constrained-layer" damping material like Dynamat Xtreme. The thin aluminum "Constraining layer" dramatically increases the effectiveness of the damping material. I used this stuff on my car and the results are pretty impressive. So, I know that it will work well on the 811B.
    Baron030

  11. #11
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    Read what Jean (B&KMan) says here:

    http://audioheritage.org/vbulletin/s...0544#post90544

  12. #12
    Senior Member Storm's Avatar
    Join Date
    Jun 2006
    Location
    Phoenix, Arizona
    Posts
    1,259

    question..

    I have a pair of 846U speakers and where the horns are mounted there is wood on the sides and top and bottom, along with foam (not insulation). The foam fits on the sides and top and bottom of the horn. Is this an ample horn dampering or do I need to get inside the cabinet and put stuff directly on top and bottom of the horn?

    Thanks.


  13. #13
    Webmaster Don McRitchie's Avatar
    Join Date
    Apr 2003
    Location
    Winnipeg, Canada
    Posts
    1,753
    No, that foam has negligible impact on damping the horn. It is intended to address diffraction problems caused by HF reflections from the sidewalls of the enclosure that extend beyond the horn mouth.
    Regards

    Don McRitchie

  14. #14
    Senior Member Storm's Avatar
    Join Date
    Jun 2006
    Location
    Phoenix, Arizona
    Posts
    1,259
    Quote Originally Posted by Don McRitchie
    No, that foam has negligible impact on damping the horn. It is intended to address diffraction problems caused by HF reflections from the sidewalls of the enclosure that extend beyond the horn mouth.
    OK...so, Don - what do I use?

    Does the Model 19 fix that problem of the horn? Why didnt they address the diffraction on the 19's with foam like they did on the 846u's?

    Can you hear the "ring" in the 19's or is that non-existent?

    In your opinion, should I sell the 846's and get a pair of 19's?

    Thanks.

    -Storm

  15. #15
    Gary L
    Guest
    Hi Storm. I think the ring is inherent in all 811B horns no matter what cabinet they are in. I am not familiar with the 511 horn but suspect it too has the ring.
    When I had my original 19s they came with foam inserts around the face and bell of the horns. Best way to describe it, just about the consistency of the foam used on temperpedic beds. It disintegrated after many years and turned to goo.
    I have 19 clones now so the inserts made for real 19s won't work for me or for Valencia owners.
    I am going to order the dynamat stuff and just consider it another project along the path of audio bliss.
    I did want to get away easy and spray them with some form of gunk but think you all here have changed my mind on this approach. I do want them to look good so I cut templates and will make the mat fit in all the right places and out of sight.

    Thanks for all the great info.
    Off to read what Zilch suggested now.

    Gary

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. i need your help - everest Horn
    By MatthiasA in forum Lansing Product General Information
    Replies: 18
    Last Post: 02-27-2013, 04:31 PM
  2. NEW 1.5 inch horn for 4345 / 4343
    By subwoof in forum Lansing Product DIY Forum
    Replies: 114
    Last Post: 07-23-2008, 05:47 AM
  3. 2397 horn - varnish and adapter
    By gerard in forum Lansing Product Technical Help
    Replies: 36
    Last Post: 02-01-2006, 05:44 AM
  4. Early Corner Horn Klipsch Style Help/ID Needed
    By david28613 in forum General Audio Discussion
    Replies: 5
    Last Post: 12-30-2005, 08:58 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •