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[nismo 10+ year member]

Originally posted by lcpunk69 B.S!

bwahahaha

eric

 

[lcpunk69 10+ year member]

Originally posted by nismo bwahahaha

 

eric

Bullshit again!!

 

[LoneRanger 10+ year member]

Originally posted by bigbassman This is me calling bullshit on you, for calling bullshit on Nismo... //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

Your fuse didnt pop because fuses can withstand current levels up to 200% of their rating, for several seconds....

 

JBL techs claim the current draw, while using a giant 14volt STABLE power supply.. which is a bit optimistic.. to say the least.. They are close on the 2 ohm rating.. but completely off with a 1 ohm load...

 

First off, when I said that I never popped the fuse, I should have said "I tried to pop the fuse and couldn't" I let it play a 59hz tone (the peak in my vehicle) for about 20 minutes in both one and two ohm mode (using an audiobahn AW1505Q as my one-ohm test subject, and a AW1506Q as my two-ohm guini pig) trying to test the maximum output of the amp. I swear, the fuse never popped. I've been told that most wafer-type fuses are underrated by 10-15a, and I know that it takes several seconds to blow a fuse that large....but 20 minutes of drawing 160-165 amps should have descimated that fuse!

Secondly, my electrical system will, and has on many occasions held 14.0-14.4v of constant power @ the rear distro block with the engine running.....Jim Hudnall didn't believe it would do it either, but with a few small upgrades and a little inginuitive engeneering, it's not as optimistic as you'd think.

 

[black00 10+ year member]

Originally posted by LoneRanger First off, when I said that I never popped the fuse, I should have said "I tried to pop the fuse and couldn't" I let it play a 59hz tone (the peak in my vehicle) for about 20 minutes in both one and two ohm mode (using an audiobahn AW1505Q as my one-ohm test subject, and a AW1506Q as my two-ohm guini pig) trying to test the maximum output of the amp. I swear, the fuse never popped. I've been told that most wafer-type fuses are underrated by 10-15a, and I know that it takes several seconds to blow a fuse that large....but 20 minutes of drawing 160-165 amps should have descimated that fuse!

 

Secondly, my electrical system will, and has on many occasions held 14.0-14.4v of constant power @ the rear distro block with the engine running.....Jim Hudnall didn't believe it would do it either, but with a few small upgrades and a little inginuitive engeneering, it's not as optimistic as you'd think.

what was your box impeadance at those frequencies...?

 

[bigbassman Premium Member]

Originally posted by black00 what was your box impeadance at those frequencies...?

This is very crucial...

Loyd L.

 

[LoneRanger 10+ year member]

I got my MECP booklet right here beside me and nowhere in here can i find the term box impedence....maybe i'm not looking hard enough.

The test I performed on the amplifier took ratings assuming the impedence of the driver was that stated by the manufacturer. I figure it this way: I use my amp exclusively on audiobahn subs. If they say it's a duel two ohm coil, then to me, that's what the amp does in one ohm mode.....same goes for the duel 4's making a 2 ohm load......I know that impedence changes with the note being played and also as a factor of heat dissapation.....just seemed to take entirely too much math for me.

For the test I used sealed boxes that were fabricated by the owners of the subs. If my memory serves me correctly, the AW1506Q was in a 1.0cuft and the AW1505Q was in a 1.25.

I know by extensive testing with my own equiptment that the loudest frequency my truck will play from the rear center of the cab is 59hz. I used the MECA CD and that handy-dandy pioneer track looping feature to ensure this note was played during the testing.

The power supply will not drop below 13.8v constant supply at the back distro block. It has been measured peaking as high as 14.4v.

If you can awnser your question with this information, let me know. Otherwise, please explain to me how to figure it out. I can always go get those woofers for another round of testing if need be //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[bigbassman Premium Member]

I got the answer... small sealed box = higher reactive load = false sense of well being...

Throw the same dual 2 ohm 15 in a 4-6 cuft ported box, play the tuning frequency.. then see how long it'll go... //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Loyd L.

 

[bigbassman Premium Member]

Here's what I mean...

Actual impedence graph, generated from LSPcad, using a nominal dual 2 ohm coiled 15" sub, in a 42 liter (1.5 cuft) sealed box... coils are wired in parallel...

Nice impedence spike exactly where you were testing... makes for an easier load for the amplifier to drive...

Loyd L.

 

[Wonderbread 5,000+ posts]

SHENANIGANS!!!

lol, tahts a hell of a lot of info Lloyd... l ol.

 

[bigbassman Premium Member]

Since I can't seem to goto sleep tonight.. here's the same woofer as used above.. in a 5 cuft ported box.. tuned to 40hz.... notice the impedence graph now...

Loyd L.

 

[LoneRanger 10+ year member]

Lloyd:

Seems awful dam suspicious that the impedence spikes EXACTLY where I was testing in that box.......is it just some odd characteristic that a sealed 1.0 cubic foot box would spike exactly at my truck's peak frequency, or do I smell something foul? I know I didn't set it up that way.....

Also, where and how did you figure that Q value for the box.....i think maybe that has something to do with the spike.

 

[bigbassman Premium Member]

Originally posted by LoneRanger Lloyd:

 

Seems awful dam suspicious that the impedence spikes EXACTLY where I was testing in that box.......is it just some odd characteristic that a sealed 1.0 cubic foot box would spike exactly at my truck's peak frequency, or do I smell something foul? I know I didn't set it up that way.....

 

Also, where and how did you figure that Q value for the box.....i think maybe that has something to do with the spike.

that spike is a typical characteristic of any sub.. placed in that box... There's really nothing that can be done about it.... Altering volume, can cause the spike to change frequency wise ( larger boxes the spike happens lower in the frequency range, and vice versa) Woofers can react a little differently, but for the most part... all will have that peak in the 50-60hz range...

And altering the Box Q, as it's shown in the program, just raises impedence even further...

Finding, and taking advantage of actual impedence, is a major trick in SPL.... It's why people run D2's at .5 ohm nominal, and why I'm running 4 ohm stable class A/B amps at 1.2 ohm nominal daily.... //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif The definition for nominal, as it pertains to car audio means: existing or being something in name or form only...

Loyd L.

 

[LoneRanger 10+ year member]

TEACH ME, OH GREAT BASS MAN!

What you just said has really got my wheels spinning.......I'd like to talk to you some time about a few tricks that just came to mind. I have ICQ and Yahoo but no AIM.....let me know if we can hook up in one of those formats

 

[bigbassman Premium Member]

Originally posted by LoneRanger TEACH ME, OH GREAT BASS MAN!

 

What you just said has really got my wheels spinning.......I'd like to talk to you some time about a few tricks that just came to mind. I have ICQ and Yahoo but no AIM.....let me know if we can hook up in one of those formats

I've got yahoo messenger.... if you want.. email me at LLdawg69@yahoo.com with your screename.. and I'll get with you late tonight... I'm on my way out now..

Loyd L.

 

[black00 10+ year member]

//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif ......throw that mecp booklet away....we can teach you much more than that folded toilet paper can....