I should add a few context notes here on the above tests.
The room is a very cluttered media room - carpeted but full of speakers, subs and furniture - it's my temporary work space.
The panels are leaned against a support (another speaker - edge on) with a lump of fibrefill to absorb vibes, and are sitting on the floor with another bit of fibrefill beneath.
The mic is sitting on a cardboard box (LOL)
Altogether certainly not an ideal environment for reflections, but I'm really just showing the differences found between the single and dual exciters so it's a relative case only.
OH- And the panels are RAW - no damping or other finish applied at this stage.
Cheers
Eucy
The room is a very cluttered media room - carpeted but full of speakers, subs and furniture - it's my temporary work space.
The panels are leaned against a support (another speaker - edge on) with a lump of fibrefill to absorb vibes, and are sitting on the floor with another bit of fibrefill beneath.
The mic is sitting on a cardboard box (LOL)
Altogether certainly not an ideal environment for reflections, but I'm really just showing the differences found between the single and dual exciters so it's a relative case only.
OH- And the panels are RAW - no damping or other finish applied at this stage.
Cheers
Eucy
I'm getting a 650hz broadband peak on many of my panels. I suspect it has something to do either with panel dimensions or with coincident frequency. Using REW in RTA mode, I mitigate that peak it a little by moving a weight around (a 30g fender washer) until I find the position that damps the peak, and then stick it in place.
Funny thing though, is that that peak does not sound as repulsive to the ear as what it should be according to the graphs. .
That's true.....I used a notch filter to knock it out and I couldn't hear the difference...
I'll also try and locate the area affecting it
anyone tried a big polystyrol ball with a sound exciter and dsp?
https://www.diyaudio.com/community/threads/diy-spherical-esl.415610/post-7747796
https://www.diyaudio.com/community/threads/diy-spherical-esl.415610/post-7747796
Hi there,
Did anyone used High Impact Polystirene ???
seem to give wide range, and it comes in 1mm thicckness.
Wondered if i could make a sub making a panel with low F0 but also low Fcrit but seems bending stiffness, sup. mass term is inverted in those expresions...
Did anyone used High Impact Polystirene ???
seem to give wide range, and it comes in 1mm thicckness.
Wondered if i could make a sub making a panel with low F0 but also low Fcrit but seems bending stiffness, sup. mass term is inverted in those expresions...
Quick question. Apologies if this has already been addressed:
Does doubling the number of exciters increase sensitivity by 3 dB?
Does doubling the number of exciters increase sensitivity by 3 dB?
After reading a bit more on this subject, I suppose using these as the walls of a horn for a line of the slim GRS planars is out of the question? The sensitivity and output capability mismatch would be huge, for one thing, plus they're bipolar instead of dipolar.
I'm still kinda curious about this, though.
I'm still kinda curious about this, though.
I think not exactly, where you drive the panel, changes which modes u excite so it wouldn't be a simple 3dB gain, you may get more modes excited by using more exciters which would translate in more planar response. (more peaks and dips in the same freq range that rise RMS value). I believe they would def help in the lower range because of cahnges in BL of the system.
Is there a sketch or diagram of how this is assembled? I am not quite seeing how it is constructed. Two panels mounted at their edges to a single actuator mounted to a wood strip?
Maybe ask him? IDK if he still uses it:
https://www.facebook.com/joppe.peelen
(some invisible hand seem to have wiped out all the papers in the drive folder... i may reupload someday but its all in a broken computer).
Best regards!
https://www.facebook.com/joppe.peelen
(some invisible hand seem to have wiped out all the papers in the drive folder... i may reupload someday but its all in a broken computer).
Best regards!
Maybe they all started a "How To Test Your DML Panel" thread, that's what this thread has sadly become.
Are these meant to be pistonic or DML devices?
Two opposed pistonic ones would be sort of like Devialet in concept.
Two spherical DML’s would be interesting. Although the modes may be very different and rather high - more of a tweeter.
You need a thinner shell - able to flex and bend - spherical paper mache might work. Use the shell as a mandrel and layup some plaster of Paris soaked paper - tissue or newsprint etc. But keep it thin.
Those more adventurous might try layup of very thin carbon fiber.
Hello xrk971.
He explains in the video that the coil is attached to the panels by paper strip.
It is very similar to the rubanoide design except the paper splits in two to form a tweeter area in-between the two boards.
This is my interpretation of the design in the video.
He says it is dml , but I would probably call this more of a bending wave panel.
But it would be easy to change and play around with this design.
Steve.
Thanks for the explanation, Steve.
Btw, I just noticed that this thread has 2M+ views and 12,000 posts! Wow - I never expected this level of interest. Very cool to see how this thread has developed.
Btw, I just noticed that this thread has 2M+ views and 12,000 posts! Wow - I never expected this level of interest. Very cool to see how this thread has developed.
Maybe.. but I hope not... We're not at the finish line yet
For my part, I've always sought a balance between listening and measuring.
Unfortunately, recently, my hearing has deteriorated significantly, and so I can no longer simply trust what I can hear, and need to rely more on measurements to reinforce what I am hearing... It's a @#@# nuisance.
Never mind... The quest continues... and I believe I'm progressing..👍🤞👌
Eucy
In theory, with traditional speaker cones wired in parallel, and for the same power input, yes, a 3db increase in sensitivity is standard. But with exciters on a bending wave panel, the sensitivity increase fluctuates according to frequency and driver positioning.
I've found that the recommended driver placement (by Dayton, Chalmer's etc) for multiple drivers jus does not work. And I find that the optimum placements vary according to panel. Even when I construct identical panels, with identical dimensions, then the driver placement sometimes varies quite substantially.
I use REW's live RTA function to pin-point driver optimum placement by watching the live frequency response while slowly moving the drivers around the panel. The first placement of a single driver rarely delivers a peak-free, notch-free response. So I find the best response by moving the driver around while watching RTA and then glue the driver down. Then ditto the second, third etc etc. I wire the drivers in series/parallel for a 4-ohm load when using 4-ohm drivers.
As you increase the number of drivers, then the peaks and notches tend to even out nicely. This is because the different driver positions activate different modes across the panel, which a single driver cannot do.
I find that four drivers are optimum, and anything more than that does not give much benefit. For hi-fi use, I would suggest multiple smaller drivers, 5W or 10W or so, since these should give better high frequency response than a single large driver.
Apologies for the TLDR answer.