small_lump_of_green_putty

[quote name='bumnote' post='528392' date='Jun 30 2009, 10:06 AM']Wouldnt a metal car body expand and contract more that wood?[/quote] Wood is porous and cellulose based. Its filled with little pockets of air that expand and contract with temperature. The fibres in the wood also swell and contract with moisture content. Any of you who have needed to tweak necks in winter will know about this already.

[quote name='benwhiteuk' post='528375' date='Jun 30 2009, 09:52 AM']Not sure that they were suggesting that he should use car paint...[/quote] Point I was making (badly) was that its worth checking the spray painter knows the difference. Spray paint for wood is designed to be a bit more flexible. I'm not saying this will definitely happen but there is a RISK that if the body expands and contracts too much then it will crack the finish. Both poly and nitro bodies are known to do this although nitro bodies are much more sensitive. [quote name='steve-soar' post='528448' date='Jun 30 2009, 11:07 AM']High gloss poly lacquers are totally fine for wood.[/quote] If you say so, I know some who disagree.

Automotive paints don't normally allow for the expansion and contraction of wood so there's a risk that if a paint designed for metal car bodies is used on wood, it might crack with the next sudden change in temperature or humidity. There are spray paints that are available for wood though which do allow for this expansion and contraction.

Just found this too, which makes for interesting reading : [url="http://www.diyaudio.com/forums/showthread/t-140741.html"]http://www.diyaudio.com/forums/showthread/t-140741.html[/url] I can't visualise how the motors transfer the rotary motion into linear motion though.

[quote name='escholl' post='524602' date='Jun 26 2009, 08:25 AM']i believe they use various forms of feedback to help increase the linearity of the cone movement -- basically giving the amp more control over the driver.[/quote] wasn't billy sheenan using them at one point?

Good god, an X-Max of 27.3mm?!!! Is that how Servo drive subs work too, or is it a different mechanism?

[quote name='alexclaber' post='524509' date='Jun 26 2009, 07:36 AM']If it wasn't sealed you'd hear air whistling as it leaks around the cone under compression or rarefaction. Alex[/quote] OK thanks for that mate. So do you reckon that whistling could be designed out with a set of piston rings? I was just thinking that if the cone and the surround were air tight but otherwise not fixed to each other, then the excursion could be potentially much greater.

Hmm, thanks. That explains why a speaker works but it doesn't explain the need for a seal.

I dunno what the fuss is all about. I've drunk a glass every day and I feel GREAT!

[quote name='Mr. Foxen' post='524234' date='Jun 25 2009, 11:09 PM']Friction and sealing. Hard to get a seal between moving parts without lots of friction, and you don't wanna be oiling your cab between songs.[/quote] I still don't understand why a seal is important around the edges. As for the lubrication, there's something called teflon these days, isn't there?

the Real Thing was an oblique reference to your Fender Jazz. Nice to know how they measure up though, I'd imagine you must be one of the most experienced Jazz Bass enthusiasts on the forum now.

[url="http://www.bassnw.com/Used%20Basses/zon_sonus_8_st_trans_charcoal.htm"]http://www.bassnw.com/Used%20Basses/zon_so...ns_charcoal.htm[/url]

why are surrounds necessary anyway? why isn't it possible to design a speaker that has something in common with a piston? thats pretty much how a speaker operates anyway isn't it? a piston for moving air?