| Spasticteapot |
For the sake of my sanity, my first speaker project (that should actually work) is a pair of RadioShack 40-1041 FR drivers in a 4" PVC pipe TL.
Rob Samson's PVC pipe design
I know that the bass on these type of TL's is not great, and the midrange can be bad, too. So, what if I added a baffle?
I have some convenient 2'x3' (600mmx900mm) acrylic panels that would be ideal. How would I mount this on the end of my TL to improve the sound? |
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| v-bro |
I think it would be ugly to say the least...
Maybe you can build a notch-lowpass filter combination to enhance things a bit...
You can connect one between the source and the amp...
I made these for on my bike (see picture), not the best sound, but much better than my sony active speakers....
The version I built with a monacor sp-60/8 has quite stunning bass reproduction! This one I made active with two t-amps each side and a 1" softdome, sold them right away to a friend who had to have them for his car....Have no pics, sorry...
Hope I've been of some help to you...:) |
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| ocool_15 |
the baffle will increase the output on higher frequencies mainly when your close to the speaker. Usually referred to as baffle step. Try it but I can't see much difference anywhere else.
You can try an infinite baffle. where you would just use the board. |
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| v-bro |
| They mostly require a lot of eq-ing too.... |
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| Spasticteapot |
| quote: | Originally posted by v-bro
They mostly require a lot of eq-ing too.... |
An oval-shaped baffle will boost the sound from about 100hz to about 3 khz. I think that this should help fix the baffle step loss.
Also, the design will be quite snazzy; I'm using clear acrylic, after all. |
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| Dumbass |
| quote: | Originally posted by Spasticteapot
For the sake of my sanity, my first speaker project (that should actually work) |
This implies that you've tried other projects that don't work? |
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| Spasticteapot |
| quote: | Originally posted by Dumbass
This implies that you've tried other projects that don't work? |
More accurately, my first project that's being built to proper speaker specs. I've put a speaker driver in a cardboard box, and failed so far in my first two attempts at a Gainclone, but nothing that would constitute a decent listening device.
A piece of 2x4 inside some PVC pipe is pretty simple. Adding a baffle would allow me to adjust for baffle step loss without any messy crossovers. |
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| v-bro |
| You might want to add an extra driver and cabinet and DO very simply filter (first or second order lowpass "pllxo" or "loudspeaker filter") the higher octaves out... |
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| loninappleton |
I'm fascinated by the use of PVC and have been for a
while.
For your consideration, here is something that borders
on an art project as sculpture:
http://tpluspod.com/rtl/fostex%20PVChorn.html
My PVC experiments have included using baffles made
from pressed cork pot stands which you can find in
various diameters at your local home center. These
things are circular and backed by fiberboard.
They're not very sturdy but should at least give a
noticeable effect. |
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| Spasticteapot |
| quote: | Originally posted by loninappleton
I'm fascinated by the use of PVC and have been for a
while.
For your consideration, here is something that borders
on an art project as sculpture:
http://tpluspod.com/rtl/fostex%20PVChorn.html
My PVC experiments have included using baffles made
from pressed cork pot stands which you can find in
various diameters at your local home center. These
things are circular and backed by fiberboard.
They're not very sturdy but should at least give a
noticeable effect. |
Interesting. Thanks for the tip!
I'll probbably just use cardboard 'till I find the desired dimensions. |
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| Scottmoose |
| Perfect for a Karlson application. Might have to look into doing a Sonotube TL subwoofer with a K-slot at some point. |
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| v-bro |
I saw that pvc-horn before by the way, very cool design!
You can order a kit to build them. :cool: I've tried to source pvc-adaptor pieces that go from small-to large diameters but didn't find much info on it...:( |
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| Spasticteapot |
| quote: | Originally posted by v-bro
I saw that pvc-horn before by the way, very cool design!
You can order a kit to build them. :cool: I've tried to source pvc-adaptor pieces that go from small-to large diameters but didn't find much info on it...:( |
Link go boom!
I can see what you mean, though. Seeing as how these are likely to end up having a custom-built amp, a filter before the amplifier is cake. |
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| v-bro |
I would like to design my owm horn from pvc, that's why I'm looking for
a great variety of PVC adaptor pieces...
Thanks for reminding me of the design, don't know if I could have found it again, or would have thought about it in the first place...:) |
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| Spasticteapot |
| quote: | Originally posted by v-bro
I would like to design my owm horn from pvc, that's why I'm looking for
a great variety of PVC adaptor pieces...
Thanks for reminding me of the design, don't know if I could have found it again, or would have thought about it in the first place...:) |
You might want to consider a different approach.
By filling the tube with plates of 2" insulation foam with holes in the middle of decreasing size, and then glassing the resulting cone, you could get a similar effect, but very cheaply. (A 10' piece of 4" PVC is 16$. A 4"->3" adapter is 6$. And you're going to need quite a few of them.) |
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| loninappleton |
Other main pvc design-- the one I started out with
is the PVC Periscope located at Full Range Driver Forum.
I ran the design for a while with RS 1197 and then
got adventurous and added another pipe length
so the total was about 81 inches-- about the same
as one of Bill Fitzmaurices tuba designs.
All the fittings are at the local home shop of your choice.
The baffle is a toilet wax ring fitting glued onto a circular
mounting piece
For those tricky bits, a plumbing supply shop should
be able to ID the pieces.
Oh yeah, the Spiral Horn:
http://www3.ocn.ne.jp/~hanbei/eng-rear.html
Looks great but a construction project that always
looked daunting to me. |
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| Spasticteapot |
| quote: | Originally posted by loninappleton
Other main pvc design-- the one I started out with
is the PVC Periscope located at Full Range Driver Forum.
I ran the design for a while with RS 1197 and then
got adventurous and added another pipe length
so the total was about 81 inches-- about the same
as one of Bill Fitzmaurices tuba designs.
All the fittings are at the local home shop of your choice.
The baffle is a toilet wax ring fitting glued onto a circular
mounting piece
For those tricky bits, a plumbing supply shop should
be able to ID the pieces.
Oh yeah, the Spiral Horn:
http://www3.ocn.ne.jp/~hanbei/eng-rear.html
Looks great but a construction project that always
looked daunting to me. |
I think that the Periscopes are also tapered TLs. I'm not sure, though - half the images won't load. |
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| v-bro |
Thanks Spasticteapot and Loninappleton, very inspiring :worship:
I want to build a couple of loudspeakers on the request of some "neighborhood rebels" who liked my bike-speakers. They want to do some (illegal :D ) partying and need speakers that are light enough to run away with when the cops come.
So I thought about making a plaster cast, to make a lot of them quick and easy...:smash: :smash: :smash: :smash: :smash: :smash: :smash:
Got it pretty well figured-out in my head; start with two positive moulds out of soft wood (?), one slightly larger than the other in order to create the "wall-thickness" in the end...
The larger pos.mould will be put in the plaster (surface treated with silicone and grease all the times and casts will be released with compressed air...) and sawed in two halfs (negative moulds). The smaller pos.mould will not be made negative, but will be also sawed in half and placed on small blocks that are as thick as "wall-thickness" in the negative moulds.
I was thinking of using some kind of epoxy and spray it in through a hole in the bottom, than just slide off excess epoxy with a bar (like a bartender smooths the foam on a beer).:drink:
Glue the two halfs together in the end. :o
I thought of making "wall-thickness" not to bulky a the start and either build it up by glueing small stones on the surface (for in livingrooms) or leave it light and portable..
I than either have the choice of a hifi-driver and a horn out of heavy material (for in livingrooms) or a PA-driver and a horn out of light material ( for outside-use).
For the last one I wonder if anyone has suggestions on a light driver that can really play loud from a 40 watt (at 4 ohms) class D amp?
Preferably a full-range driver...
I was thinking of an 8" or preferably smaller...
Suggestions would be highly appreciated...:angel: |
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| Spasticteapot |
| Anything made by Fostex. The FE166 has an efficiency of 93+ db/w. |
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| v-bro |
That looks like a pretty hifi driver indeed, thanks.
But for PA use I want something really low weight and high eff., I looked at the "neolyte" from "galaxy audio":
http://www.galaxyaudio.com/galaxystore.html
Freq response:
http://www.galaxyaudio.com/IM2/SPLvsFreq.jpg
The only thing that bothers me is the fact that many sources claim it to be 96db/W/m sensitivity. I think the response graph shows differently...:(
I think it would help if it were just a little bit larger (6 to 8" instead of 5"), just can't find any neodyme 6" or 8" fullrange.... |
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| loninappleton |
| quote: | Originally posted by Spasticteapot
I think that the Periscopes are also tapered TLs. I'm not sure, though - half the images won't load. |
James may be having having prob.s at Full range driver forum.
The Periscope is just 4" diam. PVC with an elbow at the top
and I port at the base. I couldn't find it to tell the truth.
The baffle in the origianl design is square and mdf.
Where are you in Wisconsin? |
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| Spasticteapot |
| quote: | Originally posted by loninappleton
James may be having having prob.s at Full range driver forum.
The Periscope is just 4" diam. PVC with an elbow at the top
and I port at the base. I couldn't find it to tell the truth.
The baffle in the origianl design is square and mdf.
Where are you in Wisconsin? |
Madison. |
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| loninappleton |
| quote: | Originally posted by Spasticteapot
Madison. |
Too bad the Wisconsin DIY list didn't go anywhere.
Oh well. Still would like to see a gathering put together. |
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| Geoff H |
Don't place a baffle on the pipe, it will alter the tuning. Try changing the damping material.
I have spent a day and a half playing with a TL. A 3 inch driver sitting on top of 28" of polypipe. I had mine suspended from a camera tripod so I could adjust the distance from the open end to the floor. Ended up with about 2 1/2 inches. The damping ended up being 2 cotton/nylon blend socks (clean from the drawer) and a piece of cotton cloth! Very low tech.
The bass wasn't going to worry the neighbours, but clean down to about 50 hz. Midrange and top end crystal clear. Great transients. And from a 5 watt amp! Midrange ripple barely noticeable.
When I get some more PVC, a pair of these will replace my rear speakers. Then I might start on a sub.
Like all things, TLs are scaleable. What you learn on a little one applies
to a big one. Good luck and experiment.
Geoff |
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| Spasticteapot |
| quote: | Originally posted by Geoff H
Don't place a baffle on the pipe, it will alter the tuning. Try changing the damping material.
I have spent a day and a half playing with a TL. A 3 inch driver sitting on top of 28" of polypipe. I had mine suspended from a camera tripod so I could adjust the distance from the open end to the floor. Ended up with about 2 1/2 inches. The damping ended up being 2 cotton/nylon blend socks (clean from the drawer) and a piece of cotton cloth! Very low tech.
The bass wasn't going to worry the neighbours, but clean down to about 50 hz. Midrange and top end crystal clear. Great transients. And from a 5 watt amp! Midrange ripple barely noticeable.
When I get some more PVC, a pair of these will replace my rear speakers. Then I might start on a sub.
Like all things, TLs are scaleable. What you learn on a little one applies
to a big one. Good luck and experiment.
Geoff |
Sounds sweet. What drivers did you use? |
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| Geoff H |
Hi spasicteapot.
The driver is from a Diamond MM system supplied with Packard Bell PCs in Australia, and I think UK. I have no specs available, only an educated guess at Fr at 130Hz. Originally in a ported plastic enclosure, that resonates all over the place. OK if you don't feed bass into them.
Similar to those used in Altec Lansing ACS54s and ACS45s, though the magnets are smaller.
Altec Lansing use sealed enclosures on their satellites, and are far more rigid.
Many off these types of speakers have decent drivers in crappy plastic housings.
Geoff. |
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