hi Zygadr and all
i'm new in this forum this is my first post and i'm very interested in this project
and wanted to get involved in, try some designs ... but i'm not sure i've got it all
i've tried to read all the pages and can summarize a bit what is the "today's ideal config"
of panel/drivers to begin in the right way ... ok, for what i see:
PANELS:
- for a general rule of thumb, panel has to be stiff, thin, light and as free floating as it can be with a minimum suspension points
- core stiffness is important for the transfer of the sound and give more highs
- panel material gives the tonality of the sound, also it's self damping is important for smoothing out SPL response
synthetic materials have poor self damping in general, they are bright and coloured, natural materials have good self damping
CARDBOARD shellac treated, was the winner, have a natural sound but lacks of a bit of highs ->good but not hi fi
PLYWOOD got highs and natural sound but too heavy, lack of efficency ->not enought spl or exiters need to be more powerful
REBOARD seems make muffled sound, too much self damping (because of the honey comb absorbing energy or weight?)->not hi fi
EPS has a harsh plastic sound -> not hi fi
XPS (coated) has air and micro dynamics -> hi fi ? (warfedale used this kind of matter but not coated, paper sandwiched)
BALSA not yet reported (solid spurce and other instrument wood maybe suitable also)
HONEYCOMB not yet reported exept in reboard, the honeycomb seems to absorb the energy (honeycomb should be treated...?)
amina: aluminium honeycomb, kraft paper sandwich
tectonic: kevlar honeycomb, carbon fiber sandwich, use of little weights on the panel
podium: nomex honeycomb, mylar sandwich with some bridges to the frame to "tune the panel"
göbel DML speakers: wood with special treatment
warfedale DML speakers: XPS sandwich panel (white gatorboard?)
DIMENTIONS:
golden ratio (seems to be tectonic's one also) is 1.134:1
silver ratio (from patent) is 1.37:1
ratio from tech notes is 1.41:1
zygadr ratio is 1.33:1
j gale ratio is 3:1
- experimented good results with 4ftx3ft (zygadr) and with 2ftx6ft (j gale), maybe some other dimentions are ok ?
- the bigger the better: more bending modes=more lows, smoother SPL response (dimentions not less 4ftx3ft for good results)
- ratio seems very important for the amount of modes generated but which one to choose ?
(some people experimented good results with also 2ftx6ft or other dimentions than the recommended ones, which one to choose?)
EXITERS:
- placed ala Monacor seems to be the best, original 3M and 3M double sided tape is ok for experiments
but glues like Glfex epoxy glue are better, more highs and energy transmitted
- drivers placement: lengh of the side from the corner intersection lines 4/9, 3/7 (preferable) and 5/13
- 4 per panel is ok to give good music volume but one big would be better in sound
- reducing slightly the driving point seems to give more highs
- in commercial solutions certain models seems to have a power limit circuit protection
TECTONIC ELEMENTS (=HIWAVE=NXT)
- not the one used atm because too weak in power ?
- conception problems exepted the balanced ones
(voice coil droop -> need to be held by a back spine)
- previoulsy used: (HIAX= Hiwave, TEAX= Tectonic Elements)
TEAX 32C20-8
TEAX 32C30-4
HIAX 32C20-8 (or could be TEAX...)
HIAX 32C30-4/B (or could be TEAX...)
don't know why really they are not used anymore, maybe sound quality also ?
don't know if a audio quality comparaison has been made ...
DAYTON
- the one used atm:
DAEX 25 SHF4 (4 ohms) = flagship product (BL=4.29)
DAEX 58 FP = people's favourite (BL=5)
DAEX FH E4 = the "dark horse" (BL=3.65)
- they need also back spine helding because they are too heavy and gives weight to the panel
- amina and podium sound use HIAX 25C15-8/SF (but for some shady reasons it's not obtanaible for the public ?)
http://www.tectonicelements.com/downloads/datasheets/DS-HIAX25C15-8SF.pdf in this one the BL factor is 6.56 and it's high value is important for efficency in large panels
i hope these infos are correct and help others to understand something
what i think is i need to get some honeycomb material panels and some exiters and begin to play with asap !
i'm considering using a ribbon or planar tweeter because dml seems to have some spl problems in the highs
and also a subwoofer crossed around 250 to make a hi fi full range 2.1, 2.2 or 2.0 (3 way assembled speaker) stereo system
i'll keep you in touch about this ...
cheers