gluing together the spiral sandwich
Thank you Cal, you save my life! Had a crazy busy week and was not even back here on the thread. All 4 spirals are done and I will use your suggestion with the paper strip this weekend - excellent!
Originally I designed the drivers off center to get them closer together, because they are also separated wide by the fireplace. Off center they will be now about 2.5m or 8plus feet apart. Yes all 6 horns have different length and that will be an extra bonus I hope.
Yes I cut up some of my templates for joint tape. Made about a dozen of them in different sizes on the copy machine to help me design the real thing.
They have to be real good for me to build more than two. Was not all easy sailing to coax the spiral strips on their places.
Think I try single spiral ones next with 5 inch or 4 inch driver.
Am I seeing that correctly, that the driver is mounted off center so there will be 6 different length horns? If so you certainly have all the bases covered with tuning frequency.
The foam joint tape - is that your spiral template? hehe, what, are you only building two of these?
As far as the glue drying, I would first install a 3/8" wide strip of paper to the cardboard edge with PVA glue, let it dry and then you will have a wider surface to put your glue on for the baffle piece.
Thank you Cal, you save my life! Had a crazy busy week and was not even back here on the thread. All 4 spirals are done and I will use your suggestion with the paper strip this weekend - excellent!
Originally I designed the drivers off center to get them closer together, because they are also separated wide by the fireplace. Off center they will be now about 2.5m or 8plus feet apart. Yes all 6 horns have different length and that will be an extra bonus I hope.
Yes I cut up some of my templates for joint tape. Made about a dozen of them in different sizes on the copy machine to help me design the real thing.
They have to be real good for me to build more than two. Was not all easy sailing to coax the spiral strips on their places.
Think I try single spiral ones next with 5 inch or 4 inch driver.
Great work Cal and X and all others!
A truly expiring thread together with the generic foam core thread.
I´ve built my first Cornu, 56x56 cm, with two 2" drivers.
Purely for proving the concept, but I was not so happy with the large excursions the little drivers were force to.
So now I´m thinking of what to do next.
First is to have a larger driver for the Cornu, maybe something that is laying around and then complement it with my 2" driver(s).
So to be able to fit the larger and deeper driver I thought of extending the compression chamber in z-direction towards the listener by 2".
Actually it will be a second front to the Cornu. In the space between the two fronts will be regular 2" thick foam with an cut out chamber for the driver.
So what about the 2":ers? Well, they will be mounted in the second front with their own outcarved boxes in the 2" foam.
A quick sketch:
A truly expiring thread together with the generic foam core thread.
I´ve built my first Cornu, 56x56 cm, with two 2" drivers.
Purely for proving the concept, but I was not so happy with the large excursions the little drivers were force to.
So now I´m thinking of what to do next.
First is to have a larger driver for the Cornu, maybe something that is laying around and then complement it with my 2" driver(s).
So to be able to fit the larger and deeper driver I thought of extending the compression chamber in z-direction towards the listener by 2".
Actually it will be a second front to the Cornu. In the space between the two fronts will be regular 2" thick foam with an cut out chamber for the driver.
So what about the 2":ers? Well, they will be mounted in the second front with their own outcarved boxes in the 2" foam.
A quick sketch:
Solhaga,
Sorry to hear about large excursions on the 2 inch driver, but 55 cm is probably too big of a horn to provide enough resistance (and loading) of driver diaphragm. What driver were you using? Neat idea about extending depth out to front to accommodate larger driver. You could just make a small box that goes over the central driver chamber rather than whole thing. What is larger driver you plan on using? If it doesn't fit make sure it is not too big, and you will have a case of too much resistance or loading. The drawing you show has a rectangular opening and object adobe round hole. Are you planning on pitting a ribbon tweeter there? Anyhow, great progress. Can you post pictures of your Cornu please?
Regards,
X
Sorry to hear about large excursions on the 2 inch driver, but 55 cm is probably too big of a horn to provide enough resistance (and loading) of driver diaphragm. What driver were you using? Neat idea about extending depth out to front to accommodate larger driver. You could just make a small box that goes over the central driver chamber rather than whole thing. What is larger driver you plan on using? If it doesn't fit make sure it is not too big, and you will have a case of too much resistance or loading. The drawing you show has a rectangular opening and object adobe round hole. Are you planning on pitting a ribbon tweeter there? Anyhow, great progress. Can you post pictures of your Cornu please?
Regards,
X
Feb 9,2013
OK, so I moved the speakers off the wall over the mantel and down onto the floor and six feet apart (which I am sure is a big help). They now are on the long wall rather than the short wall of the room. WOW! what a difference. They sound so much more open and airy. Sound stage depth increased as well. Even my wife immediately commented on the improvement. The dip in the 100-125 Hz range improved slightly, but isn’t fixed. And there is now a bump at 200 Hz. The bump at 80 Hz went down (shift in room mode?), level at 63 Hz went down, and spl at 50 Hz went ip. Note that on the floor one of the horn mouths is blocked. Then I moved them up off the floor, which isn’t much of an improvement, except at 200 Hz.
Again I used the 1/3 octave warble tones on Stereophile test CD #1 to see what was happening. Here are the measurements, made with a Radio Shack meter.
Hz: dB on wall: dB on floor: up off floor:
1,000 68 68 69
200 72 77 73
160 74 73 71
125 64 66 57
100 64 65 61
80 75 71 68
63 73 69 64
50 61 64 61
So far, I still prefer the Mets, which I guess isn’t surprising, since I have built 4 pairs of them.
Cheers, Jim
OK, so I moved the speakers off the wall over the mantel and down onto the floor and six feet apart (which I am sure is a big help). They now are on the long wall rather than the short wall of the room. WOW! what a difference. They sound so much more open and airy. Sound stage depth increased as well. Even my wife immediately commented on the improvement. The dip in the 100-125 Hz range improved slightly, but isn’t fixed. And there is now a bump at 200 Hz. The bump at 80 Hz went down (shift in room mode?), level at 63 Hz went down, and spl at 50 Hz went ip. Note that on the floor one of the horn mouths is blocked. Then I moved them up off the floor, which isn’t much of an improvement, except at 200 Hz.
Again I used the 1/3 octave warble tones on Stereophile test CD #1 to see what was happening. Here are the measurements, made with a Radio Shack meter.
Hz: dB on wall: dB on floor: up off floor:
1,000 68 68 69
200 72 77 73
160 74 73 71
125 64 66 57
100 64 65 61
80 75 71 68
63 73 69 64
50 61 64 61
So far, I still prefer the Mets, which I guess isn’t surprising, since I have built 4 pairs of them.
Cheers, Jim
Attachments
Thanks for you response X.
Yeah, I think I will go for a smaller Cornu for my 2":ers, and then perhaps just one. A larger Cornu will have to wait for a while.
They are the EAD E60s by the way, I got a surplus when I did my FAs.
Any suggestions for Cornu size?
My work so far with the Cornus turned out really shabby, perhaps there will be pics for the next one.
Yeah, I think I will go for a smaller Cornu for my 2":ers, and then perhaps just one. A larger Cornu will have to wait for a while.
They are the EAD E60s by the way, I got a surplus when I did my FAs.
Any suggestions for Cornu size?
My work so far with the Cornus turned out really shabby
, perhaps there will be pics for the next one.
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Thanks for you response X.
Yeah, I think I will go for a smaller Cornu for my 2":ers, and then perhaps just one. A larger Cornu will have to wait for a while.
They are the EAD E60s by the way, I got a surplus when I did my FAs.
Any suggestions for Cornu size?
My work so far with the Cornus turned out really shabby
The E60 is a nice driver, I think Cal may have tried it. It should better than a 2 in driver I used from a Logitech computer speaker. I would go with a 14 to 16 inch cornu x 3 in to 3.25 in deep.
Good lick!
I have been experimenting with different types of music on the FE108eS Cornu horns. If mine sound anything like the commercial product, then I heartily agree with the review that called them highly colored. But for some material, like solo guitar, they are simple magic: jaw dropping, holographic presentation. Listening to Sharon Isben, Jason Vieaux and John Williams is a you are there experience.
Female vocals and solo violin are similar.
Building the Cornus has been a lot of fun, even if I don't want to keep them around.
Cheers, Jim
Female vocals and solo violin are similar.
Building the Cornus has been a lot of fun, even if I don't want to keep them around.
Cheers, Jim
Jim Shearer,
I know what you mean about the magical sound for certain material. Female vocals, and jazz with horns or guitars really shine with the cornu. This is what made me want to get the word out to everyone about these cabinets. Nice to hear that your set worked well. As you can see, installing them on a proper wall really makes a difference. Holographic you are there describes it right on
Thanks for sharing.
X
I know what you mean about the magical sound for certain material. Female vocals, and jazz with horns or guitars really shine with the cornu. This is what made me want to get the word out to everyone about these cabinets. Nice to hear that your set worked well. As you can see, installing them on a proper wall really makes a difference. Holographic you are there describes it right on
Thanks for sharing.
X
I actually have the Jordan J6T. Didn't have much luck with it.
I like to think of it more as UFA [uncontrolled frequency augmentation]
So true. I am also amazed by the way those cabinets give the impression of a larger driver.
Yup, mine were delivered to the speaker warehouse just this morning...
...now what to build next?
Sunday's Project
Been working up designs for the 1" Tang Band FR speakers in an 8" Cornu. Thought I'd try the 6 Horn design, but couldn't get the dividers to work because the tolerances were too close. Reverted to the 4-horn spiral. Using a fiber gasket material, 1/32" thick, that I got from an auto supply store. Cuts easily, and is rigid in compression. It came rolled, but I cut 1" x 26" widths and left tightly rolled over night. Took the .pdfs scaled to 8" and used spray adhesive to attach the print to the back of commercial grade floor tiles (cut to size on a table saw). Gluing the spirals went pretty fast; for the ends where they run straight along the sides I cut pieces of tile to fit. To stick the top on I put a thick coat of spray adhesive on the back plate, threaded the wires through while standing everything on an edge, then clamped together using some 1/8" plywood for backing. Before gluing I stuffed some wool behind the drivers.
Looks O.K., sounds horrible with cutting in and out. The wires on the speakers are so fine it's hard to get them attached well (even with soldering). Will do some troubleshooting, but the wife just walked in and turned the amp off saying she couldn't take it anymore. Well, that's development: win some, lose others!
Been working up designs for the 1" Tang Band FR speakers in an 8" Cornu. Thought I'd try the 6 Horn design, but couldn't get the dividers to work because the tolerances were too close. Reverted to the 4-horn spiral. Using a fiber gasket material, 1/32" thick, that I got from an auto supply store. Cuts easily, and is rigid in compression. It came rolled, but I cut 1" x 26" widths and left tightly rolled over night. Took the .pdfs scaled to 8" and used spray adhesive to attach the print to the back of commercial grade floor tiles (cut to size on a table saw). Gluing the spirals went pretty fast; for the ends where they run straight along the sides I cut pieces of tile to fit. To stick the top on I put a thick coat of spray adhesive on the back plate, threaded the wires through while standing everything on an edge, then clamped together using some 1/8" plywood for backing. Before gluing I stuffed some wool behind the drivers.
Looks O.K., sounds horrible with cutting in and out. The wires on the speakers are so fine it's hard to get them attached well (even with soldering). Will do some troubleshooting, but the wife just walked in and turned the amp off saying she couldn't take it anymore. Well, that's development: win some, lose others!
Attachments
Jsouder,
Wow, floor tiles and gasket material! You really are trying some neat alternatives there. Does it sound bad due to loose wires or is sound bad? Prezden made a small one for a 1 inch driver with some success but I think it may have been bigger. Very cool, and glad you are thinking out of the box! Thanks for sharing.
X
Wow, floor tiles and gasket material! You really are trying some neat alternatives there. Does it sound bad due to loose wires or is sound bad? Prezden made a small one for a 1 inch driver with some success but I think it may have been bigger. Very cool, and glad you are thinking out of the box! Thanks for sharing.
X
jsouder, great idea with the gasket material. 1/32" that´s only 0,8 mm, right?
Isn´t it hard to get the whole box rigid enough?
Perhaps it is if it is only 1" deep though.
I´m using floor dampener, 5 mm thick XPS foam.
The initial horn is then a little bit harder to get correct:
Perhaps the gasket material could be used in the beginning for flexibility and then have foam for rigidity.
Doing some workout:
Hopefully I will be able to measure these tonight:
Isn´t it hard to get the whole box rigid enough?
Perhaps it is if it is only 1" deep though.
I´m using floor dampener, 5 mm thick XPS foam.
The initial horn is then a little bit harder to get correct:
Perhaps the gasket material could be used in the beginning for flexibility and then have foam for rigidity.
Doing some workout:
Hopefully I will be able to measure these tonight:
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jsouder- sad to hear they didn't work out for you
The ones I made were the same size. They turned out really well. The sound is much more that one would ever expect from a 1" driver. I wonder is the gasket material didn't seal up well enough. Some kinds of plastics are a bugger to glue.
cheers
The ones I made were the same size. They turned out really well. The sound is much more that one would ever expect from a 1" driver. I wonder is the gasket material didn't seal up well enough. Some kinds of plastics are a bugger to glue.
cheers
Some of you guys mentioned that one issue with the spiral horns relates to not filtering out the higher frequencies. This got me thinking about helmholtz resonators. It seems like you could add a helmholtz resonator (or band-stop filter) at the throat of the horn to help reject an unwanted frequency.
Taking the idea in another direction, you could add an expansion chamber between the driver airspace and the throat of the horn to create an acoustic lowpass filter.
Of course it seems like these could only potentially be accomplished with a 2 path horn in a square/rectangular shape.
Taking the idea in another direction, you could add an expansion chamber between the driver airspace and the throat of the horn to create an acoustic lowpass filter.
Of course it seems like these could only potentially be accomplished with a 2 path horn in a square/rectangular shape.
