bigdnfay Posted February 15, 2003 Share Posted February 15, 2003 Hi All, Been listening to my home built K-horns now for about 8 months. Now I have the bug to do alittle tweaking. My Dad just had the bed of his pick-up lined with a spray-on bed liner. After close examination, this wood appear to make an excellent horn dampener(about a 1/4 inch thick coat) and wouldn't be very expensive. It would be permanent. I was wondering if anyone had thought of this or even tried it. Need some comments before I take the plung. Big D Quote Link to comment Share on other sites More sharing options...
JohnA Posted February 15, 2003 Share Posted February 15, 2003 It must remain soft to be effective. If it hardens, it will, slightly, stiffen the horn, but that just raises the resonant frequency. Heavy and soft will absorb the vibrations and turn them into heat. Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted February 15, 2003 Share Posted February 15, 2003 I have heard about using automotive undercoat as well. This came from an audio engineer who told me to dampen my Altec 511B horns before installing and to check the ringing by tapping the unit and applying the dampening material until the ringing was suppressed. I would welcome any other advice about this. If one uses the Dynamat type of material, how is this applied and how well does it stick? C&S Quote Link to comment Share on other sites More sharing options...
Malcolm Posted February 15, 2003 Share Posted February 15, 2003 IMHO automotive bed liner compounds are too hard to be much use in damping horns. Inexpensive? Costs around $500 to have your pickup bed done! IIRC the DIY kits to do the same thing are around $100. Automotive undercoating is something else. It can be used to damp speaker cabinets, horns, etc. Only downside is it takes a long time for all of the volatile organic compounds to gas off the asphaltic base. Might have to leave your speakers in the garage for a year until you can stand to have them in the house. I have used rubberized automotive undercoating to damp and seal the sealed cavity of a horn speaker. Despite the sealed design, you could still smell it for quite a while. In my experience, Dynamat, or better yet its cheaper generic equivalent, is the best approach. Clean the horn very well with an appropriate solvent. Adhesion is only going to be as good as the surface is clean and solid. Cut the mat about 1/4" oversize in all directions. Heat the horn a bit to improve bonding of the adhesive on the mat. This is easy to do with metal horns. Should work with thermoset resins. Might be a problem with thermoplastic resins. Remove backing. Apply mat to horn. Apply pressure to mat all over to get good adhesion. A veneer roller works well for this. Trim edges. Quote Link to comment Share on other sites More sharing options...
Istari Posted February 16, 2003 Share Posted February 16, 2003 A while back HDBR mentioned a product that I've purchased and am getting ready to use. Its a spray on plastic compound that is available from Lowes. Its called Plasti-Dip, it comes in black (though you could get blue, red, yell or clear) and is removeable. You can vary the thickness of the material by spraying on multiple coats. Good thing is that after its dry it doesn't stink. Quote Link to comment Share on other sites More sharing options...
fini Posted February 17, 2003 Share Posted February 17, 2003 I believe that stuff comes as a non-aerosol, too. It's made for putting rubbery grip material on things like screwdrivers, pliers, and sterling flatware. fini Quote Link to comment Share on other sites More sharing options...
Colin Posted February 17, 2003 Share Posted February 17, 2003 I found the soft window caulking that comes in ropes of gray putty to be very easy to purchase (at Home Depot) apply and remove Quote Link to comment Share on other sites More sharing options...
cleandan Posted February 17, 2003 Share Posted February 17, 2003 Another product that works well is called "Thumb gum". It is a grey putty that is use to seal up HVAC equipment. It is pretty tacky, easily molded, does not get hard, and you can apply it as thick as your heard desires, and there is no smell or chemical worries. Thumb gum comes in different widths that are on flat rolls. The stuff I buy is about 1.5" wide, 1/8" thick, and on a 25' roll. Each side of the roll is layered with wax paper to keep things apart. You can get this stuff from your local HVAC supplier, and I think it sould be purchased at most home stores. Good luck. Quote Link to comment Share on other sites More sharing options...
jnorv Posted February 17, 2003 Share Posted February 17, 2003 I just bought some duct seal at HD. Looks like the discription of the "thumb gum" stuff except it comes in 1 and 5 pound lumps. ~ $3 for a one pound lump. Found it on the internet $90 for 50 pounds. Jim N Quote Link to comment Share on other sites More sharing options...
bigdnfay Posted February 18, 2003 Author Share Posted February 18, 2003 Thanks for all the ideas. Looks like the spray-on bed liner is out. Thanks again Guys, Big D Quote Link to comment Share on other sites More sharing options...
artto Posted February 19, 2003 Share Posted February 19, 2003 I used multiple layers of rope caulking wrapped around the midrange horns. Its still hasn't hardened after 20+ years. But I have to tell you, the one thing that made the most difference in sound quality do to vibration damping was to physically secure the Khorn solidly to the walls or foundation of the house at the tail board (for description see "artto's klipschorn room" in the architectural thread). The midrange/treble became much clearer & detailed. I'm not sure why this happens. It wasn't the result I expected (which was improved bass performance). Quote Link to comment Share on other sites More sharing options...
NOZ Posted February 19, 2003 Share Posted February 19, 2003 I heard that modeling clay will work wonders. The stranded type. Quote Link to comment Share on other sites More sharing options...
artto Posted February 19, 2003 Share Posted February 19, 2003 Noz, yeah that too. Actually the stranded rope caulk I used looks & feels very much like modeling clay, the type that is flat, stranded & rolled, except that it seems to have some kind of fiberous material in it, & it hasn't dried out. Though it never made as much difference as phyically securing the speakers to the foundation (which is, unforntunately, probably not an option for most people). Quote Link to comment Share on other sites More sharing options...
ka7niq Posted February 23, 2003 Share Posted February 23, 2003 I did the rope caulk, and took it off, sounded like **** on my CF 4's ! Now, my CF 4 is a 2 way with the big tractrix horn mid-tweeter horn and driver. They are asking this 2 inch driver to go from 700 to 20 k ! It actually crosses around 1500, but you can hear it come in much lower. perhaps the ringing in the plastic horn actually augments the response of the 2 inch aluminum dome neo magnet driver? I just gotta trust my ears, and it took away all the air, and the imaging of my speakers ? Perhaps the driver and horn are designed to work together, I dont know , just telling you my experience, for what iyts worth. Quote Link to comment Share on other sites More sharing options...
JohnA Posted February 25, 2003 Share Posted February 25, 2003 No engineer would design in horn resonances to augment the output of the driver. It's too unpredictable. He may accept some to control the cost of the system. You are undoubtedly accustomed to the sound of the ringing horn, but it should not be there. The correct sound will be one without ANY ringing or resonance ADDED by the speaker system. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted February 25, 2003 Share Posted February 25, 2003 BUT...I suppose an engineer doing any kind of final voicing on a speaker desgin would be voicing with the ringing (since no dampening was applied at that point) and thus optimize the sound without dampening...thus adding dampening might whack the sound somewhat...just a thought. tony Quote Link to comment Share on other sites More sharing options...
TBrennan Posted February 25, 2003 Share Posted February 25, 2003 And a good thought indeed Tony, a good thought indeed. Quote Link to comment Share on other sites More sharing options...
Terry N. Cruse Posted February 26, 2003 Share Posted February 26, 2003 Well Hells Bells Boys, To Dampen or not to Dampen... the CWs? I.B. Slammin Quote Link to comment Share on other sites More sharing options...
sunnysal Posted February 26, 2003 Share Posted February 26, 2003 I say try the dampening and if you like it, leave it, if not, go back to original. I think there is no right or wrong here, there is what sounds better to you. regards, tony Quote Link to comment Share on other sites More sharing options...
Terry N. Cruse Posted February 28, 2003 Share Posted February 28, 2003 Tony, John Ellis is sending me 2 upgraded Xovers to try. While the backs are off I will dampen 2CWs and keep 2CWs stock. Should be a fair A-B comparison. thanks, I.B. Slammin Quote Link to comment Share on other sites More sharing options...
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