True watts?

71buickfreak · Post by **71buickfreak** » Sun Jan 02, 2005 12:54 pm

I was going to bring up TL's very cool can be done in SPL, haven't really made the scene though. the top cars are getting smaller.
A TL is not the only way to do 1/4 wave, not the way I am talking about.
A quarter wave SPL box is similar to a TL in that you are measuring the rear wave to the terminus, but in SPL, the quarter wave is the distance from the woofer to the mic placement and the rear wave is measured from the basket through the box, the port and to the dash. lkj

Post by **GlassWolf** » Sun Jan 02, 2005 1:04 pm

ah, yeah I see what you're talking about. setting a harmonic of the waveform at the mic position.
there are several ways to use quarter-wave for enclosures.. that way, TL, folded-horn, etc..
I really like TL boxes and think they're one of the ultimate designs as far as SQ and all around benefits go, but they certainly do have drawbacks.
most of the time you see them used, it's in home speakers, with a 6" or 8" at the most for the woofer, and one sealed tweeter above that, or a small midrange and a tweeter above. pretty simple design though, and a good example of 'more isn't always better.'

71buickfreak · Post by **71buickfreak** » Sun Jan 02, 2005 1:20 pm

for example 50 hz tuning freq, wavelength is 22.5', 1/4 wave is 5.625' that is the distance from the woofer to the mic placement. the remaining 16.875' would be the length from the back of the woofer to the mic placement through the box. It can be done several ways. usually based on box placement behind the door jamb and the resonant frequency which will change any time you build a new box or move stuff like seats.

71buickfreak · Post by **71buickfreak** » Sun Jan 02, 2005 1:21 pm

http://www.sengpielaudio.com/calculator-wavelength.htm
for calculating your wavelength. unless you want to do it yourself. I forgot the formula, my cookbook is at work.

71buickfreak · Post by **71buickfreak** » Sun Jan 02, 2005 1:26 pm

I have been wanting to build a TL for my home sub for a while now, just haven't gotten to it yet. a milk crate and a piece of pvc will do a simple but effective TL. I have ssen 5" mids in a TL pound like 10". sick

71buickfreak · Post by **71buickfreak** » Sun Jan 02, 2005 1:31 pm

although one of my good friends has the #2 streetA car with 1 12 and 1 2000watt Zapco 9.0amp. 152.6 on the new meter, that's like 160 on the old style! in a CRX the box is stupid small, barely enough to fit the 3 aero ports, actually, the stick out of it!

71buickfreak · Post by **71buickfreak** » Sun Jan 02, 2005 5:51 pm

feel free to put it up on the faq page, that would be cool.

Post by **GlassWolf** » Sun Jan 02, 2005 6:45 pm

write it up in a presentable text format and email it to me at [email protected].
I can format it for the site and stick it in the FAQ section.
add the link for the wavelength calc too and I'll include that.
saves me the time of fishing everything out of the post. I'm lazy. haha