Looking for easy?
For ease of build, and I think a great way to test the effects of suprabaffles, how about this, the "Audio Lego" project page from Dave's (Planet10) tl projects site?
http://www.t-linespeakers.org/projects/sampson/index.html
For ease of build, and I think a great way to test the effects of suprabaffles, how about this, the "Audio Lego" project page from Dave's (Planet10) tl projects site?
http://www.t-linespeakers.org/projects/sampson/index.html
hitsware said:
Why? Flat FR down to 150 Hz or so should besuffiecient, beyond that you want something you can enjoy when you are done with the experiment.
Results should be translateable... ie slide up & down the FR scale. A 12" sB is going to show its effects above 150 with a corner somewhere around 380 Hz... i assume that what is of interest is the "shape of the response an octave or so above & below the corner.
dave
Re: Looking for easy?
Yes that would work... and if the "neck" holding the driver reached out some ways it would mean the box is not getting in the way. Affordable pipe thou means you'd want to usea 3" driver and maybe a nominal 8" sB (corner around 1500 Hz). This would also make room effects on the test less.
Note, a straight t-line for a typical 3" is going to be about 25" long, a subgle chunk of 4" PVC hyng from the ceiling with hi-test fishing line could provide the basic apparatus.
dave
berm said:
Yes that would work... and if the "neck" holding the driver reached out some ways it would mean the box is not getting in the way. Affordable pipe thou means you'd want to usea 3" driver and maybe a nominal 8" sB (corner around 1500 Hz). This would also make room effects on the test less.
Note, a straight t-line for a typical 3" is going to be about 25" long, a subgle chunk of 4" PVC hyng from the ceiling with hi-test fishing line could provide the basic apparatus.
dave
2nd thought on this is - how about using foam core for the suprabaffles, at least initially? You can cut out various shapes and sizes quickly and easily, and cut out a center hole the diameter of the outside of your pipe, so you could just slide the baffles up the pipe to the driver? Or slightly larger holes and push them on from the front. Should be more than good enough for proof of concept, and will make it easy to demonstrate as a project.
Good idea... very good.
After shaping, you probably want to coat them with something that smooths the surface. White PVA glue would probably work.
dave
After shaping, you probably want to coat them with something that smooths the surface. White PVA glue would probably work.
dave
berm said:
actually, our very first proof of concept (for the A126) was precision crafted from double ply corrugated cardboard and painter's masking tape
the foam core would certain be quick & nasty for PVC pipe designs, but for conventional boxes, I can envision something like 1/4" MDF panels sandwiched between the driver and the main cabinet
Re: Popete, aka half-Olivia
Dave: I'm sure you crafted this sketch in a rush - you might want to revise the notes
0 - would probably work fine with 15mm BB ply, particularly with a few holey internal braces, (i.e. driver to top / front/back panels, as well as side to side)
1 - triangular deflector would apply only to double mouth version
Note to potential builders; having built a few of pairs of various designs of Scott's, the stair-case stepped lower deflector is the most fiddly part to assemble - I'd generally recommend the single angled deflector and filling the void with your favorite high mass ballast. Even so, this enclosure will tend to be a bit tippy on carpet, so a wide plinth base (granite would be nice!) or outriggers would be advisable.
planet10 said:
Dave: I'm sure you crafted this sketch in a rush - you might want to revise the notes
0 - would probably work fine with 15mm BB ply, particularly with a few holey internal braces, (i.e. driver to top / front/back panels, as well as side to side)
1 - triangular deflector would apply only to double mouth version
Note to potential builders; having built a few of pairs of various designs of Scott's, the stair-case stepped lower deflector is the most fiddly part to assemble - I'd generally recommend the single angled deflector and filling the void with your favorite high mass ballast. Even so, this enclosure will tend to be a bit tippy on carpet, so a wide plinth base (granite would be nice!) or outriggers would be advisable.
Dave-
The foamcore (as opposed to foam) that I've used for other projects has a thick paper coating on either side that sandwiches the foam, and is quite smooth, so I don't think the glue would make that much difference. You were thinking of plain foam maybe? However, I've always found it difficult to keep the foamcore edges from getting frazzled when I cut it. Probably a really sharp utility knife or heavy-duty scissors would do the trick. It is used a lot for signs because it is easy to paint on it and it holds its shape well. It's not dead cheap, but relatively so.
chrisb-
Corrugated cardboard seems like a good idea also. Less strong, but probably wouldn't make a difference here. This could also be a good way to demonstrate the effects of different cabinet front baffles. Now this is dead cheap - free behind stores and in trash bins.
The foamcore (as opposed to foam) that I've used for other projects has a thick paper coating on either side that sandwiches the foam, and is quite smooth, so I don't think the glue would make that much difference. You were thinking of plain foam maybe? However, I've always found it difficult to keep the foamcore edges from getting frazzled when I cut it. Probably a really sharp utility knife or heavy-duty scissors would do the trick. It is used a lot for signs because it is easy to paint on it and it holds its shape well. It's not dead cheap, but relatively so.
chrisb-
Corrugated cardboard seems like a good idea also. Less strong, but probably wouldn't make a difference here. This could also be a good way to demonstrate the effects of different cabinet front baffles. Now this is dead cheap - free behind stores and in trash bins.
berm said:
Once you start carving the third dimension of the sB at least the top layer of paper goes away -- we aren't talking about just "cookie Cutting" the foam.
dave
Good point. I was just thinking of doing this in two dimensions at first, which would certainly start giving some decent measurements. Wouldn't it be a good idea to start with plain flat baffles, though, before you start throwing curved surfaces into the mix? Seems like this could greatly add to the complexity and choices & maybe could be done instead as an expansion of the project. That would then yield even more data, comparing the three-dimensional baffle to the flat one. It would show how each stage contributes to the response, so that one would not confuse what the depth curves contribute. Or not. Too much info could push this into a doctoral program on acoustic topology, or something like that. I'm thinking KISS here.
What's your thought on this?
What's your thought on this?
Another thought - since this is to get test results rather than build a permanent home set-up, though one could certainly flow out of this - what about using non-hardening modeling clay to add the third dimension? This would give you infinite flexibility not only to alter designs, but to alter them on the fly. With a successful baffle design, one could also use it to make a mold and then cast permanent baffles, say from polyester putty (i.e. Bondo) or the like. Lots of possibilities for creativity here, and maybe some useful findings - and some fun.
berm said:
It would be good as a set of baseline data, but a real-world supraBaffle will have a champher or a rounded edge.
dave
>beyond that you want something you can
>enjoy when you are done with the experiment.
God save us from making sacrifices for science .
At the expense of the veracity of the experiment.
>enjoy when you are done with the experiment.
God save us from making sacrifices for science .
At the expense of the veracity of the experiment.
- Status
- Not open for further replies.