I will likely scrap the Penthorn and do something else with the drivers.
With 10 of them you could have some fun, that's for sure.
Wait a minute, which WR's do you have? I still have 8 of the original with the black paper cone and the metal bullet phase plugs.
These Penthorns are the VWR's with the plastic cone and aluminum dust cap. Much different driver. No comparison.
With 10 of them you could have some fun, that's for sure.
Wait a minute, which WR's do you have? I still have 8 of the original with the black paper cone and the metal bullet phase plugs.
These Penthorns are the VWR's with the plastic cone and aluminum dust cap. Much different driver. No comparison.
Is this true even with a large flare in the final section of the line? I'm not trying to argue, just to understand, as I'm a beginner. It seems with a 31cm^2 driver, I'd need to size up a bit to have a decent line length instead of trying to stick with 36cm, at least for a cornu.
Despite the fact Sd is said not to have anything to do with a speaker’s design - I have had some success using it as a first order scale-up for many designs, including the Cornu and even the FH3. Way back when, I down scaled the FH3 for a 3.5in driver based on Sd alone. The design sounded great and several years later an official FH-lite plan came out and it was essentially the same size and dimensions as my crude attempt.
The overall size of a speaker is often dictated by its physical driver membrane size, and bezel mounting size. Sure, you can’t design a speaker on Sd size alone, but a speaker design with two drivers can simply be made by doubling the baffle width and keeping all else the same. This doubles the active volume.
There’s lots that can be done with a Sd and relative sizing.
You can also design a MLTL with a bass reflex as a basis - it works well for moderate Qts drivers.
Look for the AMTL thread.
The overall size of a speaker is often dictated by its physical driver membrane size, and bezel mounting size. Sure, you can’t design a speaker on Sd size alone, but a speaker design with two drivers can simply be made by doubling the baffle width and keeping all else the same. This doubles the active volume.
There’s lots that can be done with a Sd and relative sizing.
You can also design a MLTL with a bass reflex as a basis - it works well for moderate Qts drivers.
Look for the AMTL thread.
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Neither do I, that’s why I asked. I keep trying to picture it in my head and it just doesn’t compute. It’s something I’ll just have to try and sketch on paper rather than in my head (my usual method) until I figure it out or just give up.
Yes, these are the CSS VWR126's and are quite the units. I am going to have to rethink using them somewhere.
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I thought I had posted this but...
You could try something like this. I haven't made it yet, I guess we should have xrk's thoughts on the workability. ie: should we make it straight or tapered, expanding or contracting? How long should the line be? I think the bottom one has potential.
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Interesting...I’ve been picturing spirals rather than right angles which may limit it to 2 exits instead of 4. That would make it a yin-yang Cornu.
I’m also hoping X will chime in. Curious for his thoughts.
Hi Cal,
Interesting design. The length of the channel is not expanding so it might have a trombone like sound. The final expansion is probably too rapid and you will lose a lot of efficiency. Try a more gradual expansion and you can still fold it like a labyrinth and make the final expansion a bit more like a tractrix.
X
Interesting design. The length of the channel is not expanding so it might have a trombone like sound. The final expansion is probably too rapid and you will lose a lot of efficiency. Try a more gradual expansion and you can still fold it like a labyrinth and make the final expansion a bit more like a tractrix.
X
I’m intrigued by Cal’s second sketch. With X’s recommendation to make the length expand as it goes along, it would be interesting to compare the same relative sizes of square vs circle (e.g., 24” x 24” using Dave’s scaling PDF (Foam Core Board Speaker Enclosures?, post #230 of the foam core thread) vs a 24” diameter circle using Cal’s right angle path) and see how the 2 path lengths compare.
One question that comes to mind is the expansion rate of Cal’s path? Maybe expand it at each turn so it isn’t so abrupt when it reaches the opening? As X has pointed out before the right angles will act as a better low pass filter than the curves of the spiral, if that is a desirable result. The 2 methods will provide for more driver flexibility as well.
One question that comes to mind is the expansion rate of Cal’s path? Maybe expand it at each turn so it isn’t so abrupt when it reaches the opening? As X has pointed out before the right angles will act as a better low pass filter than the curves of the spiral, if that is a desirable result. The 2 methods will provide for more driver flexibility as well.
Interesting...I’ve been picturing spirals rather than right angles which may limit it to 2 exits instead of 4. That would make it a yin-yang Cornu.
Are you referring to something like this (earlier post in this thread)?
Ever think of building a Cornu Spiral horn? Now you can!
Thanks for the past reference Dave R. As I thought about it I went back to the beginning of the thread (and into the original foam core thread) and looked at some of the design offerings by the members. I had forgotten how many projects actually did use spiral walls. I do like the right angle concept so the walls can act as a low pass filter though.
Hello my oversized friend. If you guys don't know what you're dealing with, take Hagar the Horrible in his avatar and turn it into real life. Remove the horrible part and you have DaveR the 200% Norse
Dave, he was asking about a circular baffle. We have already deduced the problems with a true spiral horn vs. that with 'corners'.
Guys, I have 2 minute hand sketch you are looking at. Two minutes 'cause these old hands take that long. As I asked, I have wondered about the expanding horn line, and it would be nice to know what the driver chamber size, throat size for each of the horns along with the expansion rate, the total length, and what is acceptable for the 'dump' into the exit horn.
I might have a new project on the horizon. Those CSS VWR 126 drivers could blow the rest of these foam core out of the water. Seriously, these little drivers might really **** off my neighbours. Can't think of anything better at the moment.
Hello my oversized friend. If you guys don't know what you're dealing with, take Hagar the Horrible in his avatar and turn it into real life. Remove the horrible part and you have DaveR the 200% Norse
I can count the number of times on one hand that I've been really PO'd at someone. You could ask them how things went, but . . . well . . .
My bad. As usual, I'm a little sketchy on keeping up on current details on this thread.
I've still got plans to build one of these, using a full range driver I got from Bob Reimer some years ago. Even in retirement, things (mainly honey-do's) keep getting in the way. Guys, I have 2 minute hand sketch you are looking at. Two minutes 'cause these old hands take that long. As I asked, I have wondered about the expanding horn line, and it would be nice to know what the driver chamber size, throat size for each of the horns along with the expansion rate, the total length, and what is acceptable for the 'dump' into the exit horn.
I might have a new project on the horizon. Those CSS VWR 126 drivers could blow the rest of these foam core out of the water. Seriously, these little drivers might really **** off my neighbours. Can't think of anything better at the moment.
I'm interested in seeing how this might transpire. Hopefully someone will be able to simulate it somehow.
I haven't had time to work on this lately until today. I stole a few minutes and figured out I had a loose ground wire. I ran out of time to fix it properly, but it sounds fine when the wire is making solid contact. I can't wait to hear these things on the wall.
The thing about having corners on the box (rectangular or square … is that that provides for a larger circumference for a larger mouth and greater expansion at the end.
dave