JL 8w3: 0, Grungy Old Shop Woofers: 2

[bbeljefe]

So I built a t-line for a customer's JL Audio 8w3s. I tested the box on a 160 watt amp and ~5 minutes in, one of the JLs blows a surround. So what to do now?

Go get the 19 year old M&S Systems brand woofers out of my crusty old shop speaker box and let them do the real work. The did fine. So well that I hit em with a real amp. They did fine again.

[BoomZoom808]

http://www.speakerrepair.com/page/product/jl_audio_re-edge_kits/11-605-B-JLA.html

[john253a]

Re cone

And less power next time

My sa8v2 on 50rms gets down and comes close to bottoming out hate to see what that's doing

[bbeljefe]

Re cone

And less power next time

My sa8v2 on 50rms gets down and comes close to bottoming out hate to see what that's doing

So 160 watts is just too much power for some JL 8w3s?

EDIT: And to clarify.... that's 80 watts each. ;-)

[James365]

Re cone

And less power next time

My sa8v2 on 50rms gets down and comes close to bottoming out hate to see what that's doing

So 160 watts is just too much power for some JL 8w3s?

EDIT: And to clarify.... that's 80 watts each. ;-)

not too much power, but if you have the speaker in a t-line box... there is not enough back pressure to keep the speaker from bottoming out under that much of a load. (depending on the power rating) I'm not sure what the JL 8w3 is rated for but i know when I was running JL Audio sub's the power rating wasn't very high... I had 2 JLW7 8" subs in a t-line box that I made, sounded awesome off a 500 rms amp. but when trying to reach anything 38 Hz. or lower. it would bottom out pretty bad.

[James365]

I have pictures. but when I try to upload it's really huge.. if you would care to see. i'll share.

[James365]

[James365]

I had to sell them because I had a speeding ticket I received ever so graciously from the state of Missouri

[bbeljefe]

I had to sell them because I had a speeding ticket I received ever so graciously from the state of Missouri

I don't know what exactly the problem was but I've built a number of transmission lines and I've never had a problem with the subs bottoming out. Even the JLs in the box above didn't bottom out... the surround just failed. That said, I can make these little subs reach xmax but I don't have problems with them reaching xmech, and I've done them for everything from 6.5" to 15" subs, with as much as 6kW on one setup.

It's hard to tell from your pictures but it looks like your loading chamber is too big and the line is too short. In fact, it looks like the line is tuned at about 70 Hz, which is way too high for a sub with an Fs of about ~33 Hz and that would certainly cause the subs to unload and reach xmech. Even high quality ones.

[James365]

I had to sell them because I had a speeding ticket I received ever so graciously from the state of Missouri

I don't know what exactly the problem was but I've built a number of transmission lines and I've never had a problem with the subs bottoming out. Even the JLs in the box above didn't bottom out... the surround just failed. That said, I can make these little subs reach xmax but I don't have problems with them reaching xmech, and I've done them for everything from 6.5" to 15" subs, with as much as 6kW on one setup.

It's hard to tell from your pictures but it looks like your loading chamber is too big and the line is too short. In fact, it looks like the line is tuned at about 70 Hz, which is way too high for a sub with an Fs of about ~33 Hz and that would certainly cause the subs to unload and reach xmech. Even high quality ones.

the picture does no justice on how big the actual box was.. the box was tuned to 43 hz. yes the exit port was a little on the big side. but for the vehicle it worked out perfectly. tuned a little high for my taste. but for everyday use on music, it would hold it's own.