Hey guys, I was wondering if you foam core enthusiast's know of a decent design that could work for a center channel? I've got two Vifa TC9fd's sitting around from old foam projects.
Just finished the folded MTML design to attempt a center channel. Build came out ok, but I'm thinking the Vifa doesn't reach high enough and I might need a tweeter.
This build really renewed my enthusiasm for these foam core builds though! Does anyone have measurements for the single driver Karlsonator? I went through a few pages from around that time and I couldn't see any sp coric dimensions.
Also, does anyone have any tips for squaring up pieces? Trying to trim the edges of these foam boards just chews em up
This build really renewed my enthusiasm for these foam core builds though! Does anyone have measurements for the single driver Karlsonator? I went through a few pages from around that time and I couldn't see any sp coric dimensions.
Also, does anyone have any tips for squaring up pieces? Trying to trim the edges of these foam boards just chews em up
In post 1 of the Karlsonator thread - single 3FE25 in 0.4x:
Use a sharp razor, a metal straight edge, cut using several strokes.
Use a sharp razor, a metal straight edge, cut using several strokes.
I came across this design for a passive folded horn phone speaker here:
Folded Horn Passive Phone Speaker : 8 Steps (with Pictures) - Instructables
I thought it would be a fun project to use up left over foamboard. I can copy the design from instructables easily enough but I thought I would ask if there were any other designs that might be worth considering?
It shouldn't be too big, so that for example it could be put on a table when dining outdoors or when camping and it would be good if it could be used in portrait or landscape mode so that it could be used when watching movies.
Any thoughts?
Folded Horn Passive Phone Speaker : 8 Steps (with Pictures) - Instructables
I thought it would be a fun project to use up left over foamboard. I can copy the design from instructables easily enough but I thought I would ask if there were any other designs that might be worth considering?
It shouldn't be too big, so that for example it could be put on a table when dining outdoors or when camping and it would be good if it could be used in portrait or landscape mode so that it could be used when watching movies.
Any thoughts?
Hi Jeggles,
That is a great idea - i think I may have tried this once before. It will depend on where your phone's speaker output is. On iPhone, it is on the bottom edge. A slot holster with foam rubber gasket seal will improve the efficiency. Those drivers probably only go down to 150Hz. Ideally the horn should be at least 23in long total path to support that low of a frequency. Or a single fold on a 12 in tall construction will work. Or maybe a small Cornu with 23in spiral path length. The horn would lie flat and be omni output with phone standing straght up in a slotted holster.
That is a great idea - i think I may have tried this once before. It will depend on where your phone's speaker output is. On iPhone, it is on the bottom edge. A slot holster with foam rubber gasket seal will improve the efficiency. Those drivers probably only go down to 150Hz. Ideally the horn should be at least 23in long total path to support that low of a frequency. Or a single fold on a 12 in tall construction will work. Or maybe a small Cornu with 23in spiral path length. The horn would lie flat and be omni output with phone standing straght up in a slotted holster.
Hi X,
Thanks for your encouragement. A cornu would be fun but reading through the cornu thread the opinion seems to be that they are not so good for near-field listening. With a phone you will generally want it close at hand. I will play around with some horn designs. I have some of those sticky silicon sheets that can be used to stick a phone to things like dashboards. They should make good seals. I will try anyway.
Thanks for your encouragement. A cornu would be fun but reading through the cornu thread the opinion seems to be that they are not so good for near-field listening. With a phone you will generally want it close at hand. I will play around with some horn designs. I have some of those sticky silicon sheets that can be used to stick a phone to things like dashboards. They should make good seals. I will try anyway.
How about using a Dayton ND90-08
How would the Dayton ND90-08 or ND91 compare to the TC9FD18 for use in the 0.40x K'nator Score-N-Fold cabinet. I have a pair looking for an enclosure and just discovered this thread regarding foam cabinets. Been interested in the Karlson designs including the exponential curved speaker front panels since seeing them in the mid 50's electronics mags. (yes, I am that old!).
FYI I have designed several "standard" speakers for friends and family and myself so I am not new to the DIY scene.
George
How would the Dayton ND90-08 or ND91 compare to the TC9FD18 for use in the 0.40x K'nator Score-N-Fold cabinet. I have a pair looking for an enclosure and just discovered this thread regarding foam cabinets. Been interested in the Karlson designs including the exponential curved speaker front panels since seeing them in the mid 50's electronics mags. (yes, I am that old!).
FYI I have designed several "standard" speakers for friends and family and myself so I am not new to the DIY scene.
George
I have not sim’d the ND90 yet but the 0.4x is very forgiving. It works for TC9FD, RS100, PS95, 3FE25. I don’t see why it won’t work on ND90. Give it a try.
Thanks for the comment, now on to get some foam board.
Question on the construction of the foam cabinet. I get using a hot glue gun to assemble the horn, back, front, top and bottom to one side but what do you use to seal on the other side, Liquid Nails?
George
Question on the construction of the foam cabinet. I get using a hot glue gun to assemble the horn, back, front, top and bottom to one side but what do you use to seal on the other side, Liquid Nails?
George
Hot melt glue if you are fast! Or white PVA glue works well too and is clear. Liquid Nails is brown and makes a mess. Only use the non VOC version.
When use used the Mr Clean magic eraser as a damping material did you use them straight out of the box (with the "soap" still in it) or did you wash and dry them?
Have decided on the 0.40X design for my first build with foam. Have build 17 MDF speakers so this will be a new experience!
George
Have decided on the 0.40X design for my first build with foam. Have build 17 MDF speakers so this will be a new experience!
George
I don't think they ever have soap in them. They only need water to remove stuff like wet sanding. Get the bags of 100 sponges from China for $10 if you can wait.
Sorry for so many questions but I would like the enclosuers look nice and not like a kindergardner glued them.
I get it that the glued edge of the first side is all from the inside so that edge looks nice and clean. But what is recommended to glue the other side on? Do you just run a bead of PVA along the edge of the side and a fine thread of glue on the upright pieces and assume that that is adequate?
George
I get it that the glued edge of the first side is all from the inside so that edge looks nice and clean. But what is recommended to glue the other side on? Do you just run a bead of PVA along the edge of the side and a fine thread of glue on the upright pieces and assume that that is adequate?
George
Yes, and place lots of books on top to clamp them all down while waiting to dry. White PVA is clear and doesn't leave a visible trace. You can cover the foam with fabric or even wood veneer if you like.
Here is an example of fabric covering:
Here is an example of fabric covering:
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In brousing the thread I picked up the information that the Karlsonator is a tapered quarter tube with an acoustic lens. Any information regarding the theory of the acoustic lens and how it behaves and performs the task it does?
George
George
Much of the theory on TQWT can be found in other websites like Quarter Wavelength Loudspeaker Design
Theory Karlson acoustic lens and model is in this thread:
A Speaker that Kicks Butt in Large Spaces
Karlsonator is close to mild tapped horn in some ways - with a weakly coupled bandpass output coupler with the K aperture.
Theory Karlson acoustic lens and model is in this thread:
A Speaker that Kicks Butt in Large Spaces
Karlsonator is close to mild tapped horn in some ways - with a weakly coupled bandpass output coupler with the K aperture.
