Appropå ljudhastigheten i TL som jag själv inte begriper något av.
"There are new and improved versions of the worksheets but I have no plans to make them available. The new worksheets run in MathCad 15 and cannot be saved in a format that uses the free MathCad 8 Explorer program, this severely limits the number of potential DIY users. I do intend to add more documentation to my site and more of my designs.
With respect to the speed of sound comment, the thing that allowed accurate computer simulations of TLs was the recognition that the speed of sound is not dramatically slowed by the fiber stuffing. This myth dated back to the Bailey and Bradbury papers on TL design. Claims of 50% reduction in the speed of sound can still be found in some discussions on TL design. I wrote the following post in the Facebook group last week on the speed of sound in fiber filled TLs.
"The speed of sound is a property of the gas itself (oxygen will have a different speed of sound than nitrogen or helium for example) and the thermodynamic process the sound waves undergo. The equation for the speed of sound is shown below.
c^2 = gamma x Po / density
where gamma is a ratio of the specific heats which is process dependent and Po is the ambient pressure. For an adiabatic process, which is sound traveling in air, gamma is 1.4 so the speed of sound is approximately 344 m/sec. For an isothermal process, constant temperature expansion and contraction brought about by the fibers absorbing and releasing the heat of compression and expansion, gamma is 1.0 and the speed of sound drops to approximately 290 m/sec. The reduction is about 15%. In reality it is hard to approach isothermal in a fiber filled TL and I limit the reduced speed of sound to correspond with a gamma of 1.2 which yields about 318 m/sec or a 10% reduction.
The confusion starts when estimating the quarter wave resonant frequency of a TL. For a straight constant area TL open at one end and closed at the other the fundamental frequency can be accurately calculated as follows.
f = c / (4 x L)
The problem started when people tried to use this equation to calculate the fundamental frequency for a stuffed tapered TL and compared the value to a measured result. The measured result came out much lower so they assumed that the fiber in the TL slowed the speed of sound by viscous coupling the air to the mass of the fibers effectively increasing the density of the vibrating air column. This is wrong, the reduced frequency is caused by the tapered geometry and the speed of sound is minimally impacted.
In conclusion, be highly suspicious of any information that claims the speed of sound in a TL is reduced by more than 10%. Anybody who claims a 50% reduction in the speed of sound does not understand how a stuffed TL behaves and neglects the impact of the geometry on the resonant frequency."
There is still a lot of bad information circulating on the Internet with respect to TL design, fiber stuffing, and the speed of sound."
http://techtalk.parts-express.com/forum ... l-softwarehttp://www.quarter-wave.com/ samma Martin skriver i parts-express.
Purifi PTT6.5X04-NFA-01+Dayton Audio RST28F-4 1-1/8" +WG-300 wave guide+Komplete Audio 6+nanoDigi+2 SMSL M300SE+TPA3255 260-2-29A Topping pa3s+ .
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jag jämför utan dämpning vs totalt knöfullt med dämpning i hela lådan . För skoj skull (kanske inte blir så roligt resultat i och för sig 
