"Not trying to be a smarty pants, but isn't that what Acoustistuf is for? Looks like a little under 3#, which shouldn't break the bank. If I'm way off base, I apologize. I honestly figured that's what you were talking about, though."
No problem. I, myself, don't understand the problem. I don't know what I'm actually trying to do. Am I trying to stuff the line or am I trying to add mass? Is there a difference?
Let me try it this way: Is my PVC pipe going to "ring," as it stands, once I stuff the line? Or do I have to do TWO things, 1) stuff it as designed for the Quarter Wavelength calculations, in addition to 2) somehow adding weight to the enclosure to keep it from ringing?
Does that make sense? Unfortunately, I can't really test it. Once I glue it together, I'm done.
"Neat project, BTW."
Thanks. I appreciate that.
Dave
PS--did you mean $3? If not, then I'm really confused.
No problem. I, myself, don't understand the problem. I don't know what I'm actually trying to do. Am I trying to stuff the line or am I trying to add mass? Is there a difference?
Let me try it this way: Is my PVC pipe going to "ring," as it stands, once I stuff the line? Or do I have to do TWO things, 1) stuff it as designed for the Quarter Wavelength calculations, in addition to 2) somehow adding weight to the enclosure to keep it from ringing?
Does that make sense? Unfortunately, I can't really test it. Once I glue it together, I'm done.
"Neat project, BTW."
Thanks. I appreciate that.
Dave
PS--did you mean $3? If not, then I'm really confused.
kneadle said:
You need to damp the air column and
You need to damp any inherent ringimg in the plexi. You might even do this as part of the exterior treatment and not lose any volume. Thick (or multiple layers) of craft or wool felt, or go to the scuba shop and pick up some colorful scraps of wetsuit material, or polar fleece. The glue you use will be as much part of the damping as the material.
dave
Re: Acoustistuf
And you can bet he's not the only one, either. This spiral-behind-the-speaker idea has captured people's imaginations, you can be sure of it.
Sandy H. said:
And you can bet he's not the only one, either. This spiral-behind-the-speaker idea has captured people's imaginations, you can be sure of it.
PS: I do believe that Sandy meant three packages of Acousta-Stuff, (3# = "3 count").
A word on resonances.
A) Any stuffing-pillow stuffing, Acousta-stuff, wool, etc.-is going to be far, far more effective on high frequencies than low. I have the article from the Journal of the Audio Engineering Society that says so, in addition to the fact being known among speaker hobbyists anyway.
B) Long pieces resonate at low frequencies. Small pieces resonate at higher frequencies. Notice that string basses are considerably larger than violins? Same principle applies to pieces that make up loudspeaker enclosures. Your pipe is made up of small pieces joined together at angles.
C) Cross pieces count as braces in speaker enclosures. That is why big 4 cu ft encloures require thicker boards and bracing, while little half cubic foot enclosures get by with thinner particle board and no braces at all-the sides of the box act as braces. If all you have to do is go 4" in any direction before you hit a corner, then you don't need a brace.
D) Pipes cut at a slant don't resonate so much. Your inside wall is less than 2", the outside wall is over 6". Those pieces are not going to resonate the same as a straight piece of pipe cut 4.5". The slant suppresses resonances. Your enclosure consistes of pieces of slanted pipe put together.
I won't guarantee that all the resonances in your pipe will be suppressed when you stuff it the way you are talking about, but all these factors add up to a pipe that is far more rigid than a straight piece of 66" long, six inch diameter straight piece of PVC would be.
So relax.
A word on resonances.
A) Any stuffing-pillow stuffing, Acousta-stuff, wool, etc.-is going to be far, far more effective on high frequencies than low. I have the article from the Journal of the Audio Engineering Society that says so, in addition to the fact being known among speaker hobbyists anyway.
B) Long pieces resonate at low frequencies. Small pieces resonate at higher frequencies. Notice that string basses are considerably larger than violins? Same principle applies to pieces that make up loudspeaker enclosures. Your pipe is made up of small pieces joined together at angles.
C) Cross pieces count as braces in speaker enclosures. That is why big 4 cu ft encloures require thicker boards and bracing, while little half cubic foot enclosures get by with thinner particle board and no braces at all-the sides of the box act as braces. If all you have to do is go 4" in any direction before you hit a corner, then you don't need a brace.
D) Pipes cut at a slant don't resonate so much. Your inside wall is less than 2", the outside wall is over 6". Those pieces are not going to resonate the same as a straight piece of pipe cut 4.5". The slant suppresses resonances. Your enclosure consistes of pieces of slanted pipe put together.
I won't guarantee that all the resonances in your pipe will be suppressed when you stuff it the way you are talking about, but all these factors add up to a pipe that is far more rigid than a straight piece of 66" long, six inch diameter straight piece of PVC would be.
So relax.
Planet 10, thanks for the info. that helped a lot.
Kelticwizard, I am so glad someone else said it. I actually make that claim in my paper on the spiral enclosure, especially now that it is cut into a million (24) pieces.
Thanks all; I have my work cut out for the next few days. I'll keep everyone posted as things develop.
Dave
Kelticwizard, I am so glad someone else said it. I actually make that claim in my paper on the spiral enclosure, especially now that it is cut into a million (24) pieces.
Thanks all; I have my work cut out for the next few days. I'll keep everyone posted as things develop.
Dave
kelticwizard said:
There's so much I don't know about shorthand in the DIYaudio world. Thanks.
Dave
kelticwizard said:
so, to be absolutely pedantic, this suggests to me that the biggest bang-for-buck will be to simply stuff the things with pillow stuffing stuff. it'd certainly be easier than adhering felt to the walls. is that an accurate assessment?
/andrew - likes bang for buck
Andrew:
I can't give Kneadle a 100% guarantee, but yes, that is what I would do.
If there are any outrageous resonances, he can deal with them later.
Kneadle: after you glue the pieces together, take a well-made loudspeaker enclosure that you have and put it next to the spiral. Knock on the well made enclosure. Then knock on the spiral. The higher the frequency, and the lower the amplitude of the knock, the better. If there is no major difference, then you know you have a well-made spiral enclosure.
I can't give Kneadle a 100% guarantee, but yes, that is what I would do.
If there are any outrageous resonances, he can deal with them later.
Kneadle: after you glue the pieces together, take a well-made loudspeaker enclosure that you have and put it next to the spiral. Knock on the well made enclosure. Then knock on the spiral. The higher the frequency, and the lower the amplitude of the knock, the better. If there is no major difference, then you know you have a well-made spiral enclosure.
One more thing-about stuffing and how much the volume of the enclosure should be reduced to account for it.
According to audio author David Weems, the solid thickness of the stuffing or felt should be calculated by taking a wad of it and compressing with your fingers. If you find that you can compress it 10:1 or 50:1, then the result of that ratio should be added to the walls of the enclosure and the volume recalculated.
For pillow stuffing, I would think we could say that it is fairly negligible.
According to audio author David Weems, the solid thickness of the stuffing or felt should be calculated by taking a wad of it and compressing with your fingers. If you find that you can compress it 10:1 or 50:1, then the result of that ratio should be added to the walls of the enclosure and the volume recalculated.
For pillow stuffing, I would think we could say that it is fairly negligible.
Hi guys..
I've been the voice of caution regarding pvc resonance.. Assuming that you are willing to add material to the outside of the pipes... if it should prove necessary.. then I too would suggest that you go ahead and stuff the pipes.. glue up.. and see what happens. The big issue with speaker enclosure resonance is that this resonance occurs at particular frequencies.. and that this 'resonance' colors the sound of the speakers.. I think it is a pretty safe bet that the enclosures will resonate.. but I believe that the complex design will spread that resonance over a fairly broad frequency range. and I think this will reduce enclosure coloration..
But once there glued up ....
I also would be cautious with your stuffing... I found that I got better results if I kept the stuffing material as loose as possible.. I tried dacron and uncarded wool.. and I thought the wool sounded better.
I've been the voice of caution regarding pvc resonance.. Assuming that you are willing to add material to the outside of the pipes... if it should prove necessary.. then I too would suggest that you go ahead and stuff the pipes.. glue up.. and see what happens. The big issue with speaker enclosure resonance is that this resonance occurs at particular frequencies.. and that this 'resonance' colors the sound of the speakers.. I think it is a pretty safe bet that the enclosures will resonate.. but I believe that the complex design will spread that resonance over a fairly broad frequency range. and I think this will reduce enclosure coloration..
But once there glued up ....
I also would be cautious with your stuffing... I found that I got better results if I kept the stuffing material as loose as possible.. I tried dacron and uncarded wool.. and I thought the wool sounded better.
Brave new frontiers, here. I need to find someone in the area who's willing to critique the sound once I'm finished.
If it doesn't sound horrible, I'll only believe that it sounds terrific. Beauty is in the eye of the creator, you know.
You guys think of everything! I have no fear now.
Dave
If it doesn't sound horrible, I'll only believe that it sounds terrific. Beauty is in the eye of the creator, you know.
You guys think of everything! I have no fear now.
Dave
kelticwizard said:
I agree with kw.
Stuff it up with pillow-stuffing, dacron or polyester wool.Listen to them. See if you have a problem.
If you do deal with it from the outside. EC8010 has speakers that get the imagination flow. Yellow & Black craft felt would be a more interesting look & fuzzy feel for the caterpillar than just paint. With all the masking you would have to do for a paint job, you could just glue on fuzzy skin 🙂
dave
Just for those following along:
I tried the knock-test.
I have the pipes still duct-taped (that's where it all went, if you're wondering why your hardware store is out) in 180° pieces (4 segments), and I set one of these next to a nOrh 4.0 enclosure.
The resonance is very high on both, but the PVC has a distinct "ring." It's very short, though. So instead of a "thunk thunk, thunk" which hurts my knuckles on the nOrh, there's a "thing, thing, thing" sound, which also hurts my knuckles. The resonances are equal in decay. The timbre is different.
Dave
I tried the knock-test.
I have the pipes still duct-taped (that's where it all went, if you're wondering why your hardware store is out) in 180° pieces (4 segments), and I set one of these next to a nOrh 4.0 enclosure.
The resonance is very high on both, but the PVC has a distinct "ring." It's very short, though. So instead of a "thunk thunk, thunk" which hurts my knuckles on the nOrh, there's a "thing, thing, thing" sound, which also hurts my knuckles. The resonances are equal in decay. The timbre is different.
Dave
planet10 said:
We're WAY ahead of you 😉. She brought home the Carle book today, and we're off to the art supply store in the morning Saturday.
Dave
progress report
For those keeping score at home, I'm at the pre-glue point. I took all the pieces apart so that I could get them marked and ready to glue. But before I do that, I thought I'd tape them together with packing tape, which does not sag like duct tape. Then I got my electronics together, shoved a half bag of blanket-stuffing into each tee, and mounted the tee.
The top of the tee is temporarily covered with a piece of cardboard. I'm taking it for a test-run right now.
To tell you the truth, I don't know what to make of it. It's totally different from what I expected. The mid-range up simply shines and sparkles. It can't possibly be better (hyperbole). I WANT to say that the bass is quiet, but it's very clearly there.
These are brand new Vifa P-17-WG-00-06 drivers, so I don't know how much they'll change in the meantime. In addition, I have stuffing only in the tee section of the enclosure. I'll experiment with that. Furthermore, the enclosures are sitting on the carpeted floor, so the ports are aimed sort of helter-skelter into the ground. I wonder what placement would do to the volume of the bass frequencies.
Lastly, and as a segue, I'm listening to whatever's on KSHE right now (Sunday, February 16, 2003, 9:18pm CST USA). I've narrowed down the grand revelation of these enclosures to one of four things. I figure that those of you who helped so much ought to have a vote in the matter:
1) Led Zeppelin "Presence" on vinyl record (the way LZ was meant to be heard)
2) Miles Davis "Kind of Blue" on CD.
3) Mozart's Concerto for Piano no. 18 (K. 456), the Anda performance recorded by DG remastered to CD.
4) NASCAR on Fox (don't laugh. That's a great sound, but it's only uninterrupted for a few minutes). I'm considering this as the dark horse candidate.
Here's a pic to show where I am right now. Glue and decorating is all that's left!
Dave
For those keeping score at home, I'm at the pre-glue point. I took all the pieces apart so that I could get them marked and ready to glue. But before I do that, I thought I'd tape them together with packing tape, which does not sag like duct tape. Then I got my electronics together, shoved a half bag of blanket-stuffing into each tee, and mounted the tee.
The top of the tee is temporarily covered with a piece of cardboard. I'm taking it for a test-run right now.
To tell you the truth, I don't know what to make of it. It's totally different from what I expected. The mid-range up simply shines and sparkles. It can't possibly be better (hyperbole). I WANT to say that the bass is quiet, but it's very clearly there.
These are brand new Vifa P-17-WG-00-06 drivers, so I don't know how much they'll change in the meantime. In addition, I have stuffing only in the tee section of the enclosure. I'll experiment with that. Furthermore, the enclosures are sitting on the carpeted floor, so the ports are aimed sort of helter-skelter into the ground. I wonder what placement would do to the volume of the bass frequencies.
Lastly, and as a segue, I'm listening to whatever's on KSHE right now (Sunday, February 16, 2003, 9:18pm CST USA). I've narrowed down the grand revelation of these enclosures to one of four things. I figure that those of you who helped so much ought to have a vote in the matter:
1) Led Zeppelin "Presence" on vinyl record (the way LZ was meant to be heard)
2) Miles Davis "Kind of Blue" on CD.
3) Mozart's Concerto for Piano no. 18 (K. 456), the Anda performance recorded by DG remastered to CD.
4) NASCAR on Fox (don't laugh. That's a great sound, but it's only uninterrupted for a few minutes). I'm considering this as the dark horse candidate.
Here's a pic to show where I am right now. Glue and decorating is all that's left!
Dave
Re: Re: progress report
heh heh. I appreciate the vinyl medium, but I'm a digital man at heart. That being said, I think only a few recordings made a successful leap from tape to CD, and, in my opinion, this Miles Davis record is one of those. I have no idea why they put that alternate take on it, though. This is probably a topic for another forum.
Anyway, one vote for Presence. And what about my sound? It sounds better and better as the minutes pass. Am I being deceived by wishful ears?
Dave
planet10 said:
heh heh. I appreciate the vinyl medium, but I'm a digital man at heart. That being said, I think only a few recordings made a successful leap from tape to CD, and, in my opinion, this Miles Davis record is one of those. I have no idea why they put that alternate take on it, though. This is probably a topic for another forum.
Anyway, one vote for Presence. And what about my sound? It sounds better and better as the minutes pass. Am I being deceived by wishful ears?
Dave
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