The mid/woofer is second hand and of BBC LS 5/8 origin, originally featured in Martin Colloms' book High Performance Loudspeakers. I also have a new pair, and a pair from Alan Shaw at Harbeth.
I was looking at the Kefs when I first did an ESS rebuild of AMT 1aMs.
David Mates of SSL made some speakers under the name Orchid, using the Heil, and he used a pair as headphones saying that they went down to 100Hz at that level.
I was looking at the Kefs when I first did an ESS rebuild of AMT 1aMs.
David Mates of SSL made some speakers under the name Orchid, using the Heil, and he used a pair as headphones saying that they went down to 100Hz at that level.
Experimenting a bit with the best way to print the 50x30 adapter. The upper part is usable, but a fail. The lower part warped a bit, but only where it really does not matter. I slightly modified the model so that it does not need any support while printing and will print another one tomorrow. Slowly getting there
Attachments
Great work Pelanj.
It's exciting to follow your progress.
Even if I don't make a Synergy Horn with my Heils, I definitely want to experiment with using your adapter as a starting point for a waveguide/horn for my Heils like what Jeff Poth has done in his article here, and hopefully getting a better result than he did seeing as he wasn't able to get a better 'mating' between his Heils and the horns he made: Heil AMT1 And The Heil Horn Article By Jeff Poth
It's exciting to follow your progress.
Even if I don't make a Synergy Horn with my Heils, I definitely want to experiment with using your adapter as a starting point for a waveguide/horn for my Heils like what Jeff Poth has done in his article here, and hopefully getting a better result than he did seeing as he wasn't able to get a better 'mating' between his Heils and the horns he made: Heil AMT1 And The Heil Horn Article By Jeff Poth
Wow! What an interesting thread. I have a set of ESS-1 TOWERS that have graced my living room since the early 70s. They are identical to the ones in the picture below.
The Heils have performed flawlessly over the nearly 50-years of cranking out classical, Vintage Rock, and Smooth Jazz. Driven since the 1980s by a 230-Watt Nikko component system. They are shortly getting a crossover rebuild out at ESS in South El Monte, CA. They only charge $50 per crossover for a complete overhaul. Will report back if anyone is interested how they sound after the rebuild.
The Heils have performed flawlessly over the nearly 50-years of cranking out classical, Vintage Rock, and Smooth Jazz. Driven since the 1980s by a 230-Watt Nikko component system. They are shortly getting a crossover rebuild out at ESS in South El Monte, CA. They only charge $50 per crossover for a complete overhaul. Will report back if anyone is interested how they sound after the rebuild.
An externally hosted image should be here but it was not working when we last tested it.
AMT
pelanj, looking good!
For those that are not using the back output, how are you approaching that? I had built a 190liter net box for my 15" bass/mid and had the Heil on top with make shift baffles on either side and a block of 9" fiberglass behind to "adjust the back output "in room". Was able to push the frequency down to around 1120hz before I'd here that "reed like" sound on lower frequencies. Frankly, I like both schemes, open and attenuated but bit the bullet and decided to use the heil forward output only.
I flipped the bass/mid box over last week and sectioned the baffle to accept the heil inside the bass/mid box above the woofer. I built an enclosure for the heil that has a cover inside the bass enclosure to remove the heil if necessary. It's a snug fit right up to the backside of the heils' structure. To keep the rear absorbent material away from the diaphragm, I used a section of 4" pvc cut lengthwise to fit inside the 90 degree mouth. drilled (3) 1" holes, in the pvc, inline with the diaphragm and taped that to the heil inside the rear mouth. Filled that small area with fiberglass and placed the rear cover. Seems OK but I'd like to hear what others might be doing to compare notes. Felt block? ..or?
What I immediately noticed was the ability to drive the xo frequency lower as a result with out the audible distortion I'd hear when it was in open air. Odd. I'm working on the template to form waveguides from the heil to the cabinet face as the heils are set back to align acoustic centers. I'll post some pics when I get further along but it's starting to look like an Altec Valencia. This is a bit more compact visually then the heil on top of the enclosure. First impressions for me on sound is pretty good. All the positives of the heil sound without the "room wash" associated with the dipole output. I had this setup playing "loud" for a couple hours without any hint of driver or listening fatigue. Couldn't do that with the heil in open air in my room. Another thing I did a while ago was to remove the mesh veils on these diaphragms. They were stuck to the pleats in spots. After removal they sounded like I remembered the older diaphragms did. More detail from the recordings.
Rock on fellas!
For those that are not using the back output, how are you approaching that? I had built a 190liter net box for my 15" bass/mid and had the Heil on top with make shift baffles on either side and a block of 9" fiberglass behind to "adjust the back output "in room". Was able to push the frequency down to around 1120hz before I'd here that "reed like" sound on lower frequencies. Frankly, I like both schemes, open and attenuated but bit the bullet and decided to use the heil forward output only.
I flipped the bass/mid box over last week and sectioned the baffle to accept the heil inside the bass/mid box above the woofer. I built an enclosure for the heil that has a cover inside the bass enclosure to remove the heil if necessary. It's a snug fit right up to the backside of the heils' structure. To keep the rear absorbent material away from the diaphragm, I used a section of 4" pvc cut lengthwise to fit inside the 90 degree mouth. drilled (3) 1" holes, in the pvc, inline with the diaphragm and taped that to the heil inside the rear mouth. Filled that small area with fiberglass and placed the rear cover. Seems OK but I'd like to hear what others might be doing to compare notes. Felt block? ..or?
What I immediately noticed was the ability to drive the xo frequency lower as a result with out the audible distortion I'd hear when it was in open air. Odd. I'm working on the template to form waveguides from the heil to the cabinet face as the heils are set back to align acoustic centers. I'll post some pics when I get further along but it's starting to look like an Altec Valencia. This is a bit more compact visually then the heil on top of the enclosure. First impressions for me on sound is pretty good. All the positives of the heil sound without the "room wash" associated with the dipole output. I had this setup playing "loud" for a couple hours without any hint of driver or listening fatigue. Couldn't do that with the heil in open air in my room. Another thing I did a while ago was to remove the mesh veils on these diaphragms. They were stuck to the pleats in spots. After removal they sounded like I remembered the older diaphragms did. More detail from the recordings.
Rock on fellas!
Last edited:
I plan to contain the back wave in some kind of enclosure. The adapter can slide into a plywood box or one can use a foamcore board "dagger" a la XRK.
The new print is better, but the tolerances need to be still increased a bit, so I did shave off some bits for the next print. With a bit of sanding, it will be usable for the test unit.
The new print is better, but the tolerances need to be still increased a bit, so I did shave off some bits for the next print. With a bit of sanding, it will be usable for the test unit.
Attachments
Set it up so you can adjust the backwave level. I have been doing this using felt and fiberglass to cover the rear portion of the driver using different thicknesses. I have it set-up so it is attenuated but not completely turned off. Helps give the illusion of space adding some ambient back energy.
Rob
I was talking to "Rick" at ESS today about my AMT-1 Tower speakers and he said to move the Heil Air-motion transformers back precisely 1-inch from the factory mounting position to correct the phasing between the tweeter and woofer. Over the years they have found this setback improved the overall speaker presentation. The two bolts holding the air-motion transformer are accessed by removing the cabinet top, redrilling two new holes 1-inch further aft, and repositioning the two nut plates behind the 10-woofer. He said you can just try sliding the transformer back and forth and hear the difference before you permanently remount them in the new position.
I have to delete my first response. Yes, they have ports in the bottom. I have not heard them referred to as "DL"s before. I was looking at some google pics and I saw a lot of folks have filled that area with acoustic fiberfill.
By "TLs" I meant transmission lines, which I seem to remember ESS used at some stage.
ESS described the mesh as 'wedding veil', and it was applied to hold the peaks of the diaphragm fixed, I found it better then without in '85.
I had thought that the back could be sealed close to the diaphragm and that this would load it a little and perhaps damp it.
But I like the openness of using it 'open air' at the back.
It always looked to me as though the centres of the Heil and the woofer were well aligned.
From some measurements I did here, removing the veils evened out a couple frequency spikes in the response mainly in the 1k - 3khz range. It also removed 2-3db in the 4-8khz area. That range was pretty hot with the veil. My opinion is that they dampen the diaphragm too much, stealing away noticeable detail such as cymbal ride among other elements in the recordings.
I'm about as close to the diaphragm as practical right now. Any closer seems to veil the output. They seem to need to "breathe" a bit back there.
I like the openness as well but at elevated SPL's they can be overbearing. I like dipole systems but I could not achieve the SPL I desired without the room interference. It was honestly more than a coin flip though. It works good/better for me as a direct radiator. I think they rival Beryllium CD's, for detail anyway. Total achievable SPL is plenty for home environments. I've got the older '80's model.
Last edited:
TLs of course...
I am getting old and should have caught that.
I asked Rick at ESS about the correct amount and location of the "Resistive" Fiberfill. He stated it should not be visible in the lower port. If you stick your hand all the way in you should just feel the bottom of it. So the poor detailed breakdown picture from the brochure is correct. Whether it was for ethics or an acoustical property he was non-committal.
Last edited: