Thanks.
No, my son didn't paint them. Just some wall decals I slapped on. My son's art is a little more abstract, he's only fourteen months old
.
I wasn't sure which small drivers (I have boxes upon boxes of random crap I pulled from goodwill junk) I was going to jam in there so I made the 20x20. I used the little logitec(model Z something) because it fit in the bear's mouth. I have a lot of foam board kicking around and I'll give it another, proper go soon.
No, my son didn't paint them. Just some wall decals I slapped on. My son's art is a little more abstract, he's only fourteen months old
. I wasn't sure which small drivers (I have boxes upon boxes of random crap I pulled from goodwill junk) I was going to jam in there so I made the 20x20. I used the little logitec(model Z something) because it fit in the bear's mouth. I have a lot of foam board kicking around and I'll give it another, proper go soon.
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Using weight for a measure of general quality won't always hold true.
Motorola for example puts a huge piece of steel inside of their hand microphones to make them "Feel" like quality.
Now, don't get me wrong they ARE excellent quality but without it I do have to say they just feel like a toy.
Matter of fact a local police officer here got in a fight while trying to cuff a guy that was a foot taller than him.
He ended up using the Motorola Hand Mic as a flail to beat the guy because his other hand was pinned and couldn't reach anything else.
LOL
I do have to say though I usually have to pick up an amplifier before I buy it to see how much Iron it has in it.
Motorola for example puts a huge piece of steel inside of their hand microphones to make them "Feel" like quality.
Now, don't get me wrong they ARE excellent quality but without it I do have to say they just feel like a toy.
Matter of fact a local police officer here got in a fight while trying to cuff a guy that was a foot taller than him.
He ended up using the Motorola Hand Mic as a flail to beat the guy because his other hand was pinned and couldn't reach anything else.
LOL
I do have to say though I usually have to pick up an amplifier before I buy it to see how much Iron it has in it.
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First Pair Done & Hung!
Got the 20" traditional Cornu pair finished. Have the TB W3-881SI 3" full range drivers. Instead of Cal's suggestion to stuff with rock wool, I used some real wool from a "roving" (carded fleece) from one of our sheep.
These do sound amazing! Listening to Herbie Hancock's "River: The Joni Letters" through a Lepai 2020A. So, let's see, this is about a $50 system (without the iPod). Unbelievable!
Got the 20" traditional Cornu pair finished. Have the TB W3-881SI 3" full range drivers. Instead of Cal's suggestion to stuff with rock wool, I used some real wool from a "roving" (carded fleece) from one of our sheep.
These do sound amazing! Listening to Herbie Hancock's "River: The Joni Letters" through a Lepai 2020A. So, let's see, this is about a $50 system (without the iPod). Unbelievable!
Jsouder,
Those look great! You did a really precise job following the plan for the channels. The genuine wool hot off the back of your roving sheep takes the cake though! I am glad you ended up with a sound that you like. What channel depth did you use? Those $10 Tang Band buyouts seem to be having good success in the cornu. It also looks like the amount of stuffing you used worked out well too. Yours could be a prescription for those wanting to try a very low cost version of the cornu's. Like you said, you got love how good they sound for $50 with amplifier.
Congratulations!
Those look great! You did a really precise job following the plan for the channels. The genuine wool hot off the back of your roving sheep takes the cake though!
I am glad you ended up with a sound that you like. What channel depth did you use? Those $10 Tang Band buyouts seem to be having good success in the cornu. It also looks like the amount of stuffing you used worked out well too. Yours could be a prescription for those wanting to try a very low cost version of the cornu's. Like you said, you got love how good they sound for $50 with amplifier.Congratulations!
Thank you xrk971 for posting the six horn Puck drawing! It helped me a lot dealing with my space problem. We moved house and my big and tall Voigt-pipes would cover the windows in our preferred listening space. The area under the windows offers a 39" by 33" space and I have these exceptional great sounding RCA SL12 drivers which need a 10 3/4" cutout and worked well back-loaded in a Voigt pipe.
I got to work with your Puck diagram and arrived at a solution enlarging the underlying square grid to 1 1/2" by 1 1/2" squares. I bend the horn exits a bit to conform the rectangle and lost one turn in the center, but I think I can work with the resulting design. The resulting horns have good length: h1 is 88" or 2.24m; h2 is 52" or 1.32m;
h3 is 73" or 1.86m; h4 is 44" or 1.12m; h5 is 66" or 1.67m; h6 is 67" or 1.7m
Distance between drivers will be 2.5m when I hang them each side of the fireplace.
Should be interesting what the horns of different length do to the response curve and more important to the sound. Will be a couple of weeks before I can report on results.
Thanks a million to all the posters here, spend some time with you to read it all!
I got to work with your Puck diagram and arrived at a solution enlarging the underlying square grid to 1 1/2" by 1 1/2" squares. I bend the horn exits a bit to conform the rectangle and lost one turn in the center, but I think I can work with the resulting design. The resulting horns have good length: h1 is 88" or 2.24m; h2 is 52" or 1.32m;
h3 is 73" or 1.86m; h4 is 44" or 1.12m; h5 is 66" or 1.67m; h6 is 67" or 1.7m
Distance between drivers will be 2.5m when I hang them each side of the fireplace.
Should be interesting what the horns of different length do to the response curve and more important to the sound. Will be a couple of weeks before I can report on results.
Thanks a million to all the posters here, spend some time with you to read it all!
Glowglass,
Wow! That will be one impressive horn to see. I am glad to see someone willing to go 'off reservation' and try their own idea. Make sure you check the upper cutoff freq equation to select your throat area relative to driver chamber volume. How deep will your channels be? That is one very large driver.
Good luck!
Wow! That will be one impressive horn to see. I am glad to see someone willing to go 'off reservation' and try their own idea. Make sure you check the upper cutoff freq equation to select your throat area relative to driver chamber volume. How deep will your channels be? That is one very large driver.
Good luck!
Yes it is large, but responds best to small power, like SE tube amps.
My channels will have to be 5 1/2" deep at least to accomodate the driver. And I do have to reread the section on throat calculations and find the data on my drivers.
My channels will have to be 5 1/2" deep at least to accomodate the driver. And I do have to reread the section on throat calculations and find the data on my drivers.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The channels on that one are 2.5" deep, which with a throat of 0.5" is about 50% of the Sd area.Jsouder,
Those look great! You did a really precise job following the plan for the channels. The genuine wool hot off the back of your roving sheep takes the cake though!
Congratulations!
My next set will be 20"ers in a true spiral with 3.25" channel depth. With throats of 0.625", the area will about equal the Sd. Here's the start:
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Because I am a bit clumsy on the computer. Also I joined a few years ago as a lurker it is only now that I started dealing with the inner workings of this list.
Maybe my pics are too big in pixel count?
I see the design in my post #447, but the pictures of the driver are not up in post #450.
All pics are in my album named "electro aucoustics". Can you see them there? I made it public to members.
Maybe my pics are too big in pixel count?
I see the design in my post #447, but the pictures of the driver are not up in post #450.
All pics are in my album named "electro aucoustics". Can you see them there? I made it public to members.
Thank you for the link ikoflexer!
I need to redesign my approach or use smaller drivers. My drivers Sd is 490 square cm and the horn throat slots are way to narrow in the drawing I posted earlier.
Using the "Puck" I can play with 6 throats instead of 3 or 2 which helps. I like very much to arrive at the solution - coming back later.........
I need to redesign my approach or use smaller drivers. My drivers Sd is 490 square cm and the horn throat slots are way to narrow in the drawing I posted earlier.
Using the "Puck" I can play with 6 throats instead of 3 or 2 which helps. I like very much to arrive at the solution - coming back later.........
Glowglass,
You may be able to run with throat area as small as 0.5x Sd if you have the ratio of Sd to Vol for driver chamber large enough for cutoff freq. You may want to consider a double sided (2 horn layers separated by divider) to get a depth large enough. Assuming 4 in deep per side gives 8 inches or 20 cm deep. Assuming throat area is half of Sd, 3 throats, the throat width at the chamber is about 0.8 inches wide. I think that is manageable. You will have twice the work to build a double layered horn but then again, you have one huge driver. The double layer is necessary to prevent having a channel depth that is too tall which may buckle.
You may be able to run with throat area as small as 0.5x Sd if you have the ratio of Sd to Vol for driver chamber large enough for cutoff freq. You may want to consider a double sided (2 horn layers separated by divider) to get a depth large enough. Assuming 4 in deep per side gives 8 inches or 20 cm deep. Assuming throat area is half of Sd, 3 throats, the throat width at the chamber is about 0.8 inches wide. I think that is manageable. You will have twice the work to build a double layered horn but then again, you have one huge driver. The double layer is necessary to prevent having a channel depth that is too tall which may buckle.
Glowglass, that is a very ambitious and challenging project to pull off with a 12" driver. I would imagine 8" to be the cutoff for a design like this. I really like the asymmetrical shape of your plan because it might solve potential diffraction issues, and if it's deep enough (~8") you may also be able to avoid a dip in the upper mids from rear-wall reflections. But it will still be a MASSIVE speaker!
Back when I was considering a 3' x 3' cornu for my W5-1611's, it seemed like a viable plan until I measured 3' x 3' on my wall. All of a sudden I realized that 9 square feet of baffle was actually kind of BIG... Hey, very workable suggestions x and chaz! The double layer and the Sd/2 could save me.
Yes I like the off center place for the driver from past experiences. Would have gone closer to the top right corner,but that will mess up the horn paths. Need some time to fiddle with the horn spiral making the throats little bigger without ending up with horns too short. Need to work the math and learn to use HOLMImpulse to get some data on the drivers. Ideas are flying around the brain,but no cigar yet. Also thought about a double layer with Voight pipe style 30% access holes. Could the Puck be drawn with horns starting at zero/ middle?
Yes I like the off center place for the driver from past experiences. Would have gone closer to the top right corner,but that will mess up the horn paths. Need some time to fiddle with the horn spiral making the throats little bigger without ending up with horns too short. Need to work the math and learn to use HOLMImpulse to get some data on the drivers. Ideas are flying around the brain,but no cigar yet. Also thought about a double layer with Voight pipe style 30% access holes. Could the Puck be drawn with horns starting at zero/ middle?
Glow,
The puck as it is currently drawn is based on the Cornu function which doesn't go to zero - it asymptotically approaches a finite radius which defines the driver chamber. I think the easiest way to modify it is to do what you have done - hand draw on a grid. Both of my Cornu's were made this way. You are indeed taking on a super ambitious project - we will all be in awe when it is done. I hope you do it - it will be spectacular.
Good luck.
Regards,
X
The puck as it is currently drawn is based on the Cornu function which doesn't go to zero - it asymptotically approaches a finite radius which defines the driver chamber. I think the easiest way to modify it is to do what you have done - hand draw on a grid. Both of my Cornu's were made this way. You are indeed taking on a super ambitious project - we will all be in awe when it is done. I hope you do it - it will be spectacular.
Good luck.
Regards,
X