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Are your woofer's Squaking?

moray james

moray james

Super Member
Here is something you can try with your Heresy or any other speaker for that matter. I suggested to my brother to get some quality wool felt to do some surface damping on a pair of H3. So he picked up some real acoustical felt SAE F-11 rated which is 90% purr wool. We got 1/8 inch and 1/4 inch thick felt sheet. We applied the 1/8 inch over the face flange of the tweeter and mid horn and I placed 1/4 x 1/4 inch strips just inside the mouth opening (vertical) of the tweeter and mid horn. These additions have a very nice affect on how the speakers sounds stage and image being much improved.
This all got me to thinking about a twelve inch woofer crossing over to a small size mid horn (K701). The woofer is a large are drive when you think about crossing over at 750Hz and you are bound to get irregular interference between the mid horn and the woofer. So back to the SAE F-11 wool which is acoustically the most transparent available with the widest possible damping coefficient. I used a 1/4 inch thick layer cut out to fit into the woofer opening of the grill frame. The bass frequencies glide right through the wool felt as it was not there but the higher frequencies close to crossover and above are diminished. This leaves the mid horn to do its job without competition from the large radiating area of the woofer.
I initially did all this work with some high density fiberglass and then with some craft felt. I can assure you that buying SAE rated F-11 wool felt is the way to go and well worth the $30.00 it cost to do a pair of Heresy 3 or any other speaker. I plan to do the same on my KLF20 in the near future. Best regards Moray James.
 
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Sorry my camera just does not work. Felt on the plastic mounting flanges of the horns and a 1/4 inch thick 12 inch diametre disk inserted into the inside of the speaker grill cut out. Do you really need a picture? Maybe I can talk someone with a camera to come over to take a snap and load it into my computer. Best regards Moray james.
 
I did some more listening today comparing the woofer layer. I compared using 1/4" SAE F-11 felt to SAE 1/8" F-11 felt. After a hour of back and forth I ended up deciding to go with the 1/8" version of the SAE F-11 felt. I figured that with an overlay of light black grill cloth to hide the color of the felt it should sound perfect. The idea here is to diminish the level of the upper end response just enough to allow your brain to focus on those frequencies as coming from the mid horn only so you only have to lower the woofer out at the upper end a little to shift the focus. This has a dramatic impact on overall detail and focus of the image and stage of the speakers.
I later added some 1/8" SAE F-11 felt inside of the tweeter mouth it extends into the mouth 3/4" all the way around and also covers the entire front plastic flange of the horn. (I will be doing the same to the mid horn later). I also added a 1/4" square strip around all the inside edges of the driver cutouts in the grill. Sound is now cleaner and more detailed. This has been and is very much worth the time and cost. Tweeter time alignment with the nid horn is next on the list. Have fun, best regards Moray James.
 
This evening the H3's K701's got pulled and had their back sides covered with a layer of Dynamat type constrained layer damping material. Even before they were finished you could clearly hear the difference in the resonant character between the treated one and the untreated lens. I was expecting to hear most of any difference at higher levels. To my surprise and pleasure the difference at low level playback is clearly there to pickup on. Total cost for enough material to treat the mid and tweeter horns about $30.00 plus an evenings time. Well worth the results. I do not think anyone with a decent ear will fail to be impressed. Highly recommended. Best regards Moray James.
 
Just being curious.... were you comparing the sound of a covered K701 unmounted, to a K701 that was also unmounted?

Or were you comparing the covered 701 to a mounted 701?
 
Coytee said:
Just being curious.... were you comparing the sound of a covered K701 unmounted, to a K701 that was also unmounted?

Or were you comparing the covered 701 to a mounted 701?
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Unmounted and covered with damping to unmounted without damping, motors off in both cases. This morning I will do some high level listening, last night was all low to moderate level and I did not expect the differences I heard at those lower energy levels. More clarity a much more relaxed open sound. I can understand why some folks prefer without damping as the sound is less up front stage wise some might say less in your face but I would not agree that they sound better without damping. This is not a golden ear kind of thing but I can also imagine some people finding it to subtle to bother with, oh well each to his own. Best regards Mora James.
 
moray james said:
Unmounted and covered with damping to unmounted without damping, motors off in both cases.
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I would contend that it wasn't a fair nor correct comparison then.

I'd bet lunch (or maybe free listen to the K402's via a cell phone call and me holding the phone up to them for your pleasure :D) that it would be more fair comparison if they were mounted.

An unmounted horn might have more issues than the same horn after mounting it.

So to be fair to both, I'd suggest that wrapping one, reinstalling it and THEN rapping on them both or playing through them both would be more appropriate than using the benchmark as one unmounted.

My 402's are not only unwrapped.....but unmounted! :yikes:
 
Yes I agree that an unmounted horn will ring far more than a mounted one that goes without question. However unmounted you can get a relative idea of the coloration that the horn has without and with damping. Listening with the horns mounted clearly shows how the damping impacts the listening experience. At low levels I was surprised at how much cleaner everything sounded. My expectation had been that the difference would really show under hard drive where the horn vibration would be so much greater. Even at modest levels it was easy to appreciate the difference.
This morning after breakfast we turned the system up loud and found that the exact same benefits were there. The levels at which the system started to sound strained at are now much higher. I am Very please with the results. This is one of those "if you don't do this you can't have this" situations. For me this is a must do modification. Best regards Moray James.
PS: re your K402 being undressed Marlon Brando said in Apocalypse Now "the horror"
 
Quote "they have skinny legs, fat butts and can't cook worth a damn"

Yeah there are a lot of those around but what makes yours so special? Dimples? Best regards Moray James.

PS: Richard I love the dog what's his name and do you still have him?
 
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Sunday Morning comments. Last night we pit the Dynamat stuff on the backs of the comp driver magnets, nice touch. Then I remembered that I had not put fiberglass pade into the mid drivers (behind the diaphragms) so out they can for damping pads custom made (the tweeters in the H3 came stock with fiberglass pads) results in a word wow.
Next on the list is some stiffening for the woofer baskets likely split hard plastic plumbing pipe and some damping. also some braces from the woofer magnet to the cabinet and from the mid horn driver to the cabinet. After that some brace and stiffening work on the H3 cabinets. These speakers are really starting to sound impressive.
By the way I swapped out the Tractrix tweeter horns for a set of K79 (exponential) to match the exponential K701's I like the results very much . These things no do an astounding disappearing act, sound stage is huge with amazing sense of height which reminds me of my Acoustat 0ne plus 0nes. At the end of all there will be some cabinet volume damping experiments and I imagine I will end up filling the cavity with perlite. Perlite is the closest thing to activated charcoal that I have used for damping works almost as well but is much cleaner to use. That green expanded foam block florists use for floral arrangements. I am certain that it wont work as well as perlite but it would be a lot easier to use and install so worth a try to see. I expect bass close to 40 Hz when all is said and done, can't say where but lower than it is now. Best regards Moray James.
 
moray james said:
PS: Richard I love the dog what's his name and do you still have him?
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Tis Chloe. One of five. All found abandoned. Hate to say it but, probably the favorite of the 5 (and 2 cats)

She's a little prissy thing however, lives in the farm and can take a beating & bounce back with the best of them.

Maybe she's a country redneck girl?

That's how I found my wife.... Just like the dogs and cats, I was found on the roadside, abandonded.....she thought I looked nice enough to bring home.... :scratch2:
 

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Coytee said:
Tis Chloe. One of five. All found abandoned. Hate to say it but, probably the favorite of the 5 (and 2 cats)

She's a little prissy thing however, lives in the farm and can take a beating & bounce back with the best of them.

Maybe she's a country redneck girl?

That's how I found my wife.... Just like the dogs and cats, I was found on the roadside, abandonded.....she thought I looked nice enough to bring home.... :scratch2:
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Funny.Cute Dogs. We have a German Shepard/Lab mix... ole Jager, he is 8 now
and loves to lay by me when I have Jazz or Blues on the Cornwalls.:thmbsp:
We got him when he was 6 weeks old. My dad told me Jager does Not know he is a Dog:D he sleeps on the foot of our bed.
 
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