Well, today I purchased the insulation board for the baffle and rear wall, and had it cut to size. I'm into this project for $8 already. 😉 The next important thing, besides buying the foam board, is to get the 3'x3' plans printed up. I'm only going to make one to start with and test the concept. Glad I'm doing one of these again if for no reason than to use up all the leftover hot glue from last time.
As if it weren't obvious, well, 3'x3' is REALLY big. I made a drawing in sketchup to help me imagine it but holding the panel is different. I'm going to get in big trouble for this one. 😀
Has anyone tried mounting their cornus on opposite walls at 90° to one another?
As if it weren't obvious, well, 3'x3' is REALLY big. I made a drawing in sketchup to help me imagine it but holding the panel is different. I'm going to get in big trouble for this one. 😀
Has anyone tried mounting their cornus on opposite walls at 90° to one another?
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Just tell your wife it's only a 5 inch speaker! 😉
Yes, 9 square feet is a lot of baffle anyway you look at it.
Looking forward to seeing the build! Please post incremental progress pics if possible.
Yes, 9 square feet is a lot of baffle anyway you look at it.
Looking forward to seeing the build! Please post incremental progress pics if possible.
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As I've said before, why get in trouble? Hide them in plain sight instead.
A common home decorator trick is to stretch a square of "decorator print" material over a wooden frame and hang it on the wall. You can do this using a Cornu as the frame. Just glue tiny strips (maybe 1/4" square balsa wood) around the edges of the front baffle to lift the material slightly off the baffle. If SAF is important, get her to pick the material. To test for suitability, hold it over your mouth and try to breathe through it. If you can breathe easily, it'll likely be OK as baffle cloth.
A common home decorator trick is to stretch a square of "decorator print" material over a wooden frame and hang it on the wall. You can do this using a Cornu as the frame. Just glue tiny strips (maybe 1/4" square balsa wood) around the edges of the front baffle to lift the material slightly off the baffle. If SAF is important, get her to pick the material. To test for suitability, hold it over your mouth and try to breathe through it. If you can breathe easily, it'll likely be OK as baffle cloth.
Yes, that's exactly what I'm thinking of doing. I'm also trying to find 3'x3' posters that I can just let the drivers peek through. Anyway, I'll cross that bridge when I come to it; first step is the test speaker.
You may have a problem with a front horn sticking out of it. You will need to equalize it with a 500 Hz and lower 10 dB attenuator circuit. I think you can do this passively at line level pretty easy. The front horn is the purist way to do it - and get lots of efficiency. You can use tiny neodymium magnets on the foam front horn to hold it in place like a speaker grille so that it can be removed for WAF when not in use. Snap in place for listening (over the poster or fabric cover). Bamboo wall paper is a nice covering that goes well in a lot of decor.
I just discovered some rather powerful (and free) audio tools for Mac which could help solve the problem of EQing these speakers back to flat, so I'm not terribly concerned about the front horn for the time being (at least not while I'm using my computer/DAC as my source almost exclusively). In the meantime, see what I was able to do with the smaller cornus this morning, with minimal effort.
About the software:
Use AU plugins for free with any Apple audio software - Blogs - Computer Audiophile
About the software:
Use AU plugins for free with any Apple audio software - Blogs - Computer Audiophile
Very balanced, open and natural. The highs on these TB drivers are a little gritty though. I'm thinking of upgrading the drivers to the Dayton RS-100-8 which I expect so sound better due to the better moter, lower Fs and higher xmax. In the meantime, my W5s are unplugged and will stay that way for some time while I enjoy the cornus.
Ah.... saved from the trash heap by software! I'm glad the Cornu's are getting some listening again. 🙂
Xrk, can you just please confirm the horns' throat width before I start building? I don't think I've seen it specified yet.
Today I'm going to try kerfing the 1/2" foam board with a razor and see if it will bend to the desired radii. It wouldn't hurt to have a little extra thickness all the way around!
By the way, looking at the EQ'd cornu's response, you can see an obvious ripple pattern extending all the way through its bandwidth just like an un- or under-stuffed transmission line simulation made on MJK's software. I have a feeling that all of those dips and peaks would have been reduced had I stuffed the first 1/3 of the line more aggressively. Well, since I'll be making the rear wall if the 3' cornu removable to start with, it will give us a chance to experiment and see the effects of more or less stuffing.
Today I'm going to try kerfing the 1/2" foam board with a razor and see if it will bend to the desired radii. It wouldn't hurt to have a little extra thickness all the way around!
By the way, looking at the EQ'd cornu's response, you can see an obvious ripple pattern extending all the way through its bandwidth just like an un- or under-stuffed transmission line simulation made on MJK's software. I have a feeling that all of those dips and peaks would have been reduced had I stuffed the first 1/3 of the line more aggressively. Well, since I'll be making the rear wall if the 3' cornu removable to start with, it will give us a chance to experiment and see the effects of more or less stuffing.
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Chaz,
The throat gap isn't too critical but it should scale with drawing as follows: 70 cm Cornu has a throat of 1.19 in so 90/70=1.286. So 1.286 x 1.19 = 1.53 in. 1.5 in is fine. You can vary 25% no problem. If you use 0.5 in thick foam on channels, the channel gap will be significantly smaller.
The throat gap isn't too critical but it should scale with drawing as follows: 70 cm Cornu has a throat of 1.19 in so 90/70=1.286. So 1.286 x 1.19 = 1.53 in. 1.5 in is fine. You can vary 25% no problem. If you use 0.5 in thick foam on channels, the channel gap will be significantly smaller.
I think I will maintain the 1.5" width, and therefore subtract a little from the chamber volume instead (assuming the 1/2" material works).
Memorial day weekend means no printing shops are open, so I've got to wait until tomorrow at the earliest to get blueprints. 😡
Are there any chances enjoy listening to these speakers somewhere in Europe ?
In my opinion should in practice be a lot of trouble with the bass.
Have a nice day
RK
In my opinion should in practice be a lot of trouble with the bass.
Have a nice day
RK
The real Cornu is on your side of the pond so maybe google and see if you can arrange a listen somewhere close.
Rk,
If you mean excessively loud and colored, then yes. But for many kinds of music, it sounds great. See post 881, for example of what it may look like: about 10 dB greater than main output. Stuffing is critical to bring it down, or a front horn.
If you mean excessively loud and colored, then yes. But for many kinds of music, it sounds great. See post 881, for example of what it may look like: about 10 dB greater than main output. Stuffing is critical to bring it down, or a front horn.
Cal Weldon: The search is always important is the level of desperation. How far is it to human begins to thinking. I have heard of listening that are in different parts of the world. The organizer will provide a place somewhere in the hotel and you can spend your time and explore something by the way.
xrk971: I thought the bass speaker that is not visible. It uses the capacity of all the tunnels. In front of a full range speaker, built from the inside.
Have a nice day
RK
xrk971: I thought the bass speaker that is not visible. It uses the capacity of all the tunnels. In front of a full range speaker, built from the inside.
Have a nice day
RK
So before I commit to making the 3'x3' cornu, I'd like to see whether or not there was some optimizing that could be done for a 2-horn design. I took the original scalable design and removed the short horns, at the same time widening the long horn paths considerably. Xrk, I'm not certain what the total ramifications are for this but I wanted to see if you could sim it to see if there are any positive benefits. The blue lines represent an optional diamond-shape horn with no empty spaces. Let me know...
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Chaz,
What you describe would be the same as blocking the short horns. Widening the paths just increases the gain amplitude but the dips and peaks will still be the same. Running sim with revised geometry is a lot of work as it requires manually measuring the horn path widths and lengths with dial calipers. I think assumption of similar response with higher amplitude should be good - see below. I would recommend going with the original plan as designed.
X
What you describe would be the same as blocking the short horns. Widening the paths just increases the gain amplitude but the dips and peaks will still be the same. Running sim with revised geometry is a lot of work as it requires manually measuring the horn path widths and lengths with dial calipers. I think assumption of similar response with higher amplitude should be good - see below. I would recommend going with the original plan as designed.
X
Hi X
Would I be better off to cut driver opening larger shortening the horn length or to use a driver with a smaller Sd. If using the one with the smaller Sd is there a way that I can compensate by building up the bottom of the cavity. 😕
cheers- prez
Would I be better off to cut driver opening larger shortening the horn length or to use a driver with a smaller Sd. If using the one with the smaller Sd is there a way that I can compensate by building up the bottom of the cavity. 😕
cheers- prez
Prez,
Cut off the begining horn throat section and widen the hole if you can and put your W4-1320SIF bamboo in there.
Cut off the begining horn throat section and widen the hole if you can and put your W4-1320SIF bamboo in there.