Its 30 years ago 
But in short, I would say bigger and better well defined bass and smooth topend - more coherent soundstage
A late dane mr Duelund has later on declared polyurethane to be one of the good materials, something to do with long stringed molecules
Fact is that it stiffens, yet is very light with very good dampening with no breakup peaks
But its tricky to control and get an even layer thats thin enough, and the effect may depend on driver
But in short, I would say bigger and better well defined bass and smooth topend - more coherent soundstage
A late dane mr Duelund has later on declared polyurethane to be one of the good materials, something to do with long stringed molecules
Fact is that it stiffens, yet is very light with very good dampening with no breakup peaks
But its tricky to control and get an even layer thats thin enough, and the effect may depend on driver
most coatings...
aside from acrylic (which sprqys on fully cured and only has to off gas) take 3-4 weels to 100% cuew or or less a few days depending upon humidity. That said they will achieve most of what they will do (96-98%) in about 3 weeks. This ihas nothing to do with feeling dry and being able to handle but with being fully cured (ie. all chemical reaction has stopped). Synthetic coatings generally take a little less time and natural air drying compounds will take a little on the longer side. The is because air drying compounds form a skin wich slows the absorbtion of oxygen to polyerize the liquid closest to the substrate. No body ever likes to hear this but many have over coated cone only several days after a coating because they think more will sound better. Go one coat at a time if you have not got the experience. Multiple coats will slow further the curring process. Only coatings that atr capalized or uv cured will cure faster. Regards Moray James.
aside from acrylic (which sprqys on fully cured and only has to off gas) take 3-4 weels to 100% cuew or or less a few days depending upon humidity. That said they will achieve most of what they will do (96-98%) in about 3 weeks. This ihas nothing to do with feeling dry and being able to handle but with being fully cured (ie. all chemical reaction has stopped). Synthetic coatings generally take a little less time and natural air drying compounds will take a little on the longer side. The is because air drying compounds form a skin wich slows the absorbtion of oxygen to polyerize the liquid closest to the substrate. No body ever likes to hear this but many have over coated cone only several days after a coating because they think more will sound better. Go one coat at a time if you have not got the experience. Multiple coats will slow further the curring process. Only coatings that atr capalized or uv cured will cure faster. Regards Moray James.
Greets!
Oops! Sorry, In browsing, I managed to miss the original reference about it being a foam glue. I airbrushed drivers with a wide variety of stains, varnishes, paints, including polyurethanes, to try to get the desired result. Unfortunately I ruined a lot of old radio/TV drivers for wide BW use in the process since with no accurate measurement system the only way to know it's 'right' is to go past it.
The only glues I tried were either brushed or poured on and meant to mass load and increase stiffness, so no subtlety required, only an accurate weight scale.
GM
Oops! Sorry, In browsing, I managed to miss the original reference about it being a foam glue. I airbrushed drivers with a wide variety of stains, varnishes, paints, including polyurethanes, to try to get the desired result. Unfortunately I ruined a lot of old radio/TV drivers for wide BW use in the process since with no accurate measurement system the only way to know it's 'right' is to go past it.
The only glues I tried were either brushed or poured on and meant to mass load and increase stiffness, so no subtlety required, only an accurate weight scale.GM
The Frugel-Horn Project now has its own website (shared with some other horns)
http://www.frugal-horn.com/
dave
http://www.frugal-horn.com/
dave
Related... kinda.... sorta
Dave's driver mods inspired me to get off my duff. I'd bought some modge podge years ago, for just such a purpose (infusion into paper cones). Tried it last night: 2 light coats brushed on, diluted 1:1 into some peerless papercone 8"s. Definite improvements in stiffness.
Dave's driver mods inspired me to get off my duff. I'd bought some modge podge years ago, for just such a purpose (infusion into paper cones). Tried it last night: 2 light coats brushed on, diluted 1:1 into some peerless papercone 8"s. Definite improvements in stiffness.
Just a few questions:
1. When modeling the Frugelhorn in McBean's Hornresp I get some strong irregularities in the 100Hz to 400Hz range, and a particularly troubling looking peak @ 135Hz. This peak is about the same for a wide range of back chamber and mouth dimensions (e.g.: actual effective mouth of about 450cc, approximate mouth with curved back about 1000cc, and mouth with reflector about 2000cc). This peak does not change much with chamber resonances masked or unmasked. Could this be an artifact of the transmission line nature of this cabinet?
2. Does anybody have some real life experience as to how Hornresp results translate into measured results?
3. This may be really dumb given how much time you must be putting into this already, but I'm wondering, planet10: Have you given any thought to a bipole version of this cabinet. Lowther has used something like that in some of theirs. It would still be a "tiny" speaker.
1. When modeling the Frugelhorn in McBean's Hornresp I get some strong irregularities in the 100Hz to 400Hz range, and a particularly troubling looking peak @ 135Hz. This peak is about the same for a wide range of back chamber and mouth dimensions (e.g.: actual effective mouth of about 450cc, approximate mouth with curved back about 1000cc, and mouth with reflector about 2000cc). This peak does not change much with chamber resonances masked or unmasked. Could this be an artifact of the transmission line nature of this cabinet?
2. Does anybody have some real life experience as to how Hornresp results translate into measured results?
3. This may be really dumb given how much time you must be putting into this already, but I'm wondering, planet10: Have you given any thought to a bipole version of this cabinet. Lowther has used something like that in some of theirs. It would still be a "tiny" speaker.
johninCR: Yes, I added the nominal distance as well as trying all kinds of other distances as you would encounter in a corner installation. In general the big peak in the 135Hz range remained, even though the response curves were quite different. I'll try to attach an image of the combined response (used 100cm in this one) and the input page, maybe you can find if/where I made a mistake. Mainly, I found it a point of interest. What the in-room response with reflective corners and side walls would look like I don't even want to try to imagine; that's why I too believe in lots of listening when building a speaker (and a room).
planet10: The bipole should be another interesting version, looking forward to your design.
planet10: The bipole should be another interesting version, looking forward to your design.
Attachments
planet10: Thanks for that note, so my use of Hornresp is not completetly off the wall. Hopefully someone like Ron Clarke or Martin King can throw some light on this subject. It may just be the normal effect of a short horn and a small mouth. I'm just trying to get a feel for how to use Hornresp, still have not found a cheap version of MathCad to get to know Martin's worksheets.
johninCR: As long as the overall length has not changed, and the mouth is not smaller than 400cm^2, I think the Tombstone will model just like the Frugelhorn. Particularly as Hornresp allows for only 4 sections, so that makes it necessarry to pick some points along the flare, and use those to model to. Not to talk about modeling the corners. Thanks for looking at it.
johninCR: As long as the overall length has not changed, and the mouth is not smaller than 400cm^2, I think the Tombstone will model just like the Frugelhorn. Particularly as Hornresp allows for only 4 sections, so that makes it necessarry to pick some points along the flare, and use those to model to. Not to talk about modeling the corners. Thanks for looking at it.
GM: Thanks for reminding me. I have downloaded the free version of MathCad8 and the sample worksheet. It all certainly looks very impressive and interesting. The worksheets I downloaded in 2005 will not open, wrong version of MathCad, and naturally the free version of MathCad does not allow saving. I'll wait until I can find a copy of MathCad at ebay (and some extra time). Meanwhile I'll try to get the hang of Hornresp.
Very high WAF
my wife has not been pleased with my other projects and these puppies were winners.
the comment during construction was "there smaller than I thought." ( big speakers are a no no ).
when they were mostly complete without the tweak the comment was " those are nice"
My wifes not much of an audio person so its tough to make everyone happy.
Gex
my wife has not been pleased with my other projects and these puppies were winners.
the comment during construction was "there smaller than I thought." ( big speakers are a no no ).
when they were mostly complete without the tweak the comment was " those are nice"
My wifes not much of an audio person so its tough to make everyone happy.
Gex
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