Audio qualia

experience the real sound of music !

damping factors   n [eta]

I have re-assessed the results of the damping factors already given, and by adjusting calculations and changing bandwidths on some of the tested higher valued materials, I have found that some materials have higher values than previously given. Those below 0.2 are unchanged, those above 0.2 have been re-assessed.


Here are the revised data. Any new values have the centre of the bandpass region quoted, all attenuation out of band at 24dB/oct, as before, at a Q of 0.7071.


material frequency damping factor
balsa wood   0.013
bamboo (resinated)
chipboard   0.228
cork 850 0.127
low density fibreboard 113 0.257
hardboard 134 0.062
mahogany   0.032
mdf   0.017
oak 540 0.102
olive wood (oiled) 264 0.273
'Panzerholz' 150 0.599
  900 0.898
'Permali' 6mm 250 0.671
'Permali' 18mm 220 0.688
pine 226 0.064
365 0.104
Russian 7 ply   0.040
'Torlyte'   0.088



metals frequency
damping factor
aluminium   0.004
brass   0.013
copper 175 0.01
lead   0.032
steel   0.008




material frequency damping factor  
acetal (delrin) 121 0.013  
carbon fibre twill   0.020  
carbon fibre rod (non-twill)
239 0.061  
expanded polystyrene   0.055-0.168  
perspex (acrylic)   0.070  
polyethylene terephthalate   0.043  
polyethylene (high density) 200 0.050  
polypropylene   0.052  
ptfe ('Teflon')   0.021  
vinyl foam (hard)   0.046  
vinyl floor tile 272 0.145  



material frequency damping factor  
fired clay   0.012  
glass, strengthened   0.033  
'Pyrotek' 6mm 100 0.376  
'Pyrotek' 20mm 340 0.395
marble   0.009  
slate   0.017  
soapstone 1338 0.027  



visco elastics and soft foams    
material frequency damping factor
blutack (white) 15 0.166
closed pore foam   0.151
expanded polyethylene   0.167
foam for glass bricks   0.288
foam board (paper) 94 0.030
polyurethane foam 120 0.054
polyurethane foam block 141 0.109
above, reconstituted 82 0.149
Plasticine' 77 0.304
'Newplast' 160 0.635
rho C' [polyurethane]   0.287
smart putty'   0.134
sorbothane   0.197
tungsten loaded putty 80 0.725
Wickes' 'lead' flashing   0.161



complex materials and structures      
material frequency damping factor  
Ikea platter mat   0.062  
dilatant fluid 260 0.109  
recycled rubber crumb 109 0.348  
aluminium + polyalkane composite   0.240  
glass 'Butacite' laminate 150 0.391  
glass 'Sentryglas' laminate 247 0.317  
Al/mdf/Al composite ('Sole') 203 0.218  
glass fibre pcb (copperclad) 445 0.013  
'Trespa Meteon' 30 0.126  
'Alucobond' (Al/ldpe/Al) 300 0.187  
Page Lacquer' acrylic over mdf 100 0.315  
compressed rockwool   0.089  
candle wax 618 0.269  
vinyl record 281 0.020  
above on bare platter 181 0.054  
above, on Ikea mat 194 0.118  
above, with record clamp 117 0.100  
Shellac '78' [HMV] 330 0.014  
above on Ikea mat 287 0.257  
video disc 12”(polycarbonate?   0.033  
above on Ikea mat   0.079  
bentonite powder filled resin 100 0.518  
lead filled resin 100 0.592  
bentonite filled resin 48 0.618  
(bentonite is dry cat litter)      
resin is isophthalic polyester resin **


** the type of polyester resin seems important, it is of the isophthalic variety, but only from certain suppliers.

see here for data sheet: enter code 6398


acknowledgements, thanks:

Resin/clay mix researched and developed by Rap.

polyester resin samples prepared and provided by François LEBEAU, Annecy, France

panzerholz and aluminium laminate supplied by François LEBEAU, Annecy, France

smart putty and carbon fibre sheet  from Middlesex University, UK

'Alucobond', 'Page Lacquer', 'Trespa', compressed 'Rockwool' and DuPont samples from 's&p' Architects, London, UK

fired clay sample from 'Angela Wallwork Ceramics' Devon, UK

Aluminium/mdf/aluminium section of 'Sole' sub-chassis supplied by 'Analogue Innovation'

Pyrotech cement board samples supplied by Haydn, Australia

Permali Deho Permali ® (Densified Wood Laminate) samples supplied by Haydn, Australia


Thanks to everyone.


new blog

Sorry for these problems

The powers that overlord this website have threatened to deactivate this site for being too popular, without them getting their pound of flesh. Over the last several weeks they have withdrawn the stats counter, so that I cannot monitor the bandwidth, which is now over their specified limit. They have now stopped any change to any pages except this side panel.

So I have had to set up a new forum so that I can continue to help the hifi community. The new forum will be here:


All the pages on this site, and many more, to found on the new site.

Hope to 'see' you all on the new forum, opening soon. Dated 21 Sept 2012

the second audio qualia site continues, here:

script change history

there have been problems with the editor for, which has resulted in no new material being able to be added. So this site will remain open until the problem is fixed, but another site will be constructed to host a more practically based one. Hope to see you there, details as soon as I have found a stable platform (sounds like hifi!) kindest regards   Cats.

Featured Products

No featured products