Hi Ziggy,
How is the project coming along?
Hopefully this weekend I will get all the wood cut for the woofer section of my speakers, so in a couple of months.....we can compare some sound systems. I would sure be interested to hear these panels.
Anyway, gotta cut some wood.......
How is the project coming along?
Hopefully this weekend I will get all the wood cut for the woofer section of my speakers, so in a couple of months.....we can compare some sound systems. I would sure be interested to hear these panels.
Anyway, gotta cut some wood.......
el`Ol said:
I was thinking about paper reinforced with bamboo splinters. I had already phoned someone who runs a traditional paper mill. He asked for a mail with a detailed description of what I want. This was over a week ago and I still have no response, so I guess the project is dead.
I googled how such a "Dutch" paper mill looks like and I can imagine the problem is that it is not very well suited for hard stuff like Bamboo.
Do you think I can get carbon fibers anywhere (just fibers, not a plate, etc.)?
I found a company that not only has the chopped carbon fibers but also 700 varieties of honeycombs.
http://www.hexcel.com/Products/Core+Materials/Honeycomb/
http://www.hexcel.com/Products/Core+Materials/Honeycomb/
Does anybody have an idea why nobody is using balsa plywood? Should be one of the first materials to try, so I don´t think it has been overlooked.
to Ziggy
Hello,
thank you for the nice report about your experimentations
I think you wont go any further without measurements
I allready have done small tests with DML drivers
it is very easy to record a logsweep on them 5 to 10s
then to turn this logsweep into a pulse with the Farina's method.
with this single pulse you can know everything about
your transducers, amplitude response, distorsion, phase
you can have a look at the waterfall and so on.
If you think you are not far enough to examine these pulses
just post us the pulse.wav, we will do the job for you
By the way, if you do the same on your horn loudspeaker
the filtering can be examined too, and may be bettered...
http://pagesperso-orange.fr/pol.bct/exemples/DIY.htm
Hello,
thank you for the nice report about your experimentations
I think you wont go any further without measurements
I allready have done small tests with DML drivers
it is very easy to record a logsweep on them 5 to 10s
then to turn this logsweep into a pulse with the Farina's method.
with this single pulse you can know everything about
your transducers, amplitude response, distorsion, phase
you can have a look at the waterfall and so on.
If you think you are not far enough to examine these pulses
just post us the pulse.wav, we will do the job for you
By the way, if you do the same on your horn loudspeaker
the filtering can be examined too, and may be bettered...
http://pagesperso-orange.fr/pol.bct/exemples/DIY.htm
Because it's soft? I have 10x1000x1 sheet and shellac. Should I make a laminate 90deg with Patex Moment and measure with a piezo?
Just curious, one 27mm piezo element has R=2.1kOhm, Z=61kOhm, C=26nF. Does it mean I need sqrt(61000/8) = 81:1 transformer? That's too high IMHO.
Thanks for all the interesting links and comments guys.
At present, I have discovered that amplification is VERY important in matching up with the panels. The amplifier needs to be around 80 watts/channel, and able to deliver decent current at low impedances.
They are not necessarily power hungry......they just need the current (as do Magnepans I suppose).
I have found that a 100 watt in to 4 ohm Kenwood 2 channel receiver that is 13 years old - ABSOLUTELY wipes the floor with many amplifiers tried here (including my monster Pioneer home theatre receiver and a few expensive high end ones
).So the choice of amplifier can make or break the sound........go figure
As you can imagine, I am currently experimenting on upgrade parts modifications on this Kenwood😉
Bent, please remind me of your project. It's been a while and I can't recall what you were up to.
pol_bct........thanks, I'll try to make some sense of this and use it.
el'Ol, jzagaja, tell me more about balsa'' plywood''........never seen or heard of it. Can it be purchased or made?.........is it laminated cross grain for added strength?
Shellac will harden it.........I have tried this with cardboard sheet.
At present, I have discovered that amplification is VERY important in matching up with the panels. The amplifier needs to be around 80 watts/channel, and able to deliver decent current at low impedances.
They are not necessarily power hungry......they just need the current (as do Magnepans I suppose).
I have found that a 100 watt in to 4 ohm Kenwood 2 channel receiver that is 13 years old - ABSOLUTELY wipes the floor with many amplifiers tried here (including my monster Pioneer home theatre receiver and a few expensive high end ones
).So the choice of amplifier can make or break the sound........go figure As you can imagine, I am currently experimenting on upgrade parts modifications on this Kenwood😉
Bent, please remind me of your project. It's been a while and I can't recall what you were up to.
pol_bct........thanks, I'll try to make some sense of this and use it.
el'Ol, jzagaja, tell me more about balsa'' plywood''........never seen or heard of it. Can it be purchased or made?.........is it laminated cross grain for added strength?
Shellac will harden it.........I have tried this with cardboard sheet.
I guess I will order balsa and ceiba here:
http://www.modellbau-steinhardt.de/holz/birkenflugzeugsperrholz.html
Ceiba has better damping (maybe too good for DML) and is very floppy rectangular to the fibers.
I always try to stay below 500 g/m² because this seems to be the border for conventional fullrange drivers.
http://www.modellbau-steinhardt.de/holz/birkenflugzeugsperrholz.html
Ceiba has better damping (maybe too good for DML) and is very floppy rectangular to the fibers.
I always try to stay below 500 g/m² because this seems to be the border for conventional fullrange drivers.
Balsa or Samba can be found in every hobby shop in Poland for 4,5 EUR/m2/1mm. Typical format is 25x1000mm. Tonight will try make some laminate. I have in my mind a model made of stiff pyramid pattern excited with a long piezo custom made. In theory compression wave that is smaller than panel dimension will radiate like above coincidence peaking off axis and pyramids will convert the rest to a bending wave.
So, what does this mean to us all?.........what is your conclusion?
Seems to me that dampening has some positive effects.
Cutting corners..........hmmmmm???............NXT and PODIUM SOUND have both done this to improve sound due to corner interactions😕
Seems to me that dampening has some positive effects.
Cutting corners..........hmmmmm???............NXT and PODIUM SOUND have both done this to improve sound due to corner interactions😕
Find better position or/and balance the modes 🙂 5kHz looks to me as 3rd corner mode as exciter is on an exact center position. Sound get nicer when I put my fingers on the corners or one finger no matter where. If one piezo element is Z=65kOhm so we use only a fraction of its efficiency that is nearly 100%?
Find better position or/and balance the modes 🙂 5kHz looks to me as 3rd corner mode as exciter is on an exact center position. Sound get nicer when I put my fingers on the corners or one finger no matter where. If one piezo element is Z=65kOhm so we use only a fraction of it's efficiency that is nearly 100%?
Interestingly if you cut corners you will excite more modes between 1,5kHz and 5kHz. I can repeat experiment with 100mm round membrane with typical rubber suspension. Expecting less modes and worse sound.
Yesterday made round membrane and applied shellac with pumice and linseed oil as usual furniture coating. Sticked two piezos with a brass plates face to face and sticked to balsa on both side making push-pull, connected in- and out-of-phase. Response looks like one big resonance from the piezo plate itself and wood response below. Nothing interesting but don't see much change between a single arrangement and push-pull.
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