max db

paul mx3 · May 2004

whats the max i can expect from my polk mm100

im not really bothered about high spl but i enter into iasca competition where you get points for reacing up to 135db....

up to now ive managed to get 133.9 in competition with 1 mm100 sub run off a jl 500/1.

is there any chance i can hit the magic 135 and get maximum points in this section...

neomagus00 · May 2004

changing the box type/tuning, if you havent already

paul mx3 · June 2004

is it possible to get 135db from a single mm100....safely

my box is a specially designed for sq 3 chamber internally ported externally sealed enclosure

LittleCar_w/12s · June 2004

well you should be able to get 135 easily from that, just tweak your enclosure a bit, it'd probably run smoother with a pure sealed enclosure, but that's your call. You are running 500 to that?? Is that max or continuous?
well anyway.. Just to give you hope, i got a 127.9 runnign 2 12" off of about 200 watts total and absolutely nothing was right, so it should be possible, given a good install.
If you give us more details on what all you have, we can help you tweak your install to make it more efficient.
-Jerry

paul mx3 · June 2004

im running the sub off a jl 500/1 so depending on what you believe about the jl regulated amps it putting out up to 700 rms.

ive not actually set the gains on the amp to there maximum preclipping yet.was going to just use the jl method of setting the gains but waitin to get hold of a scope to do it properly and try and squeeze everything i can out of it.....to be honest i dont need to gain a massive amount...my only aim is the 135db to gain maximum points in that section.

i dont want to got to too much trouble because my new sub is on its way soon.....id max 12"

so just wanted to get that extra 1.1 db for now.

PoweredByDodge · June 2004

"was going to just use the jl method of setting the gains but waitin to get hold of a scope to do it properly and try and squeeze everything i can out of it....."

... if you'd used the scope you'd notice that there's no way you're getting 700w out of that... 500 - 525 i'll believe...

keep this in mind, due to the type/design of the JL mono amps, their quality is shown by remaining at or as close to that 500-ish by 1 wattage mark... if they are off by a significant enough amount, then it lends one to believe that they are neither regulated in power supply, nor in output to the extent that JL claims.

a GOOD power supply and output stage regulated amplifier will be at or very close to its rating.

try it out on the scope... find out transient specific AC resistance at a particular frequency (pick something around say 90 hertz or 100 hertz, as it should be in the "meat" of the power band), generate sine waves, record to cd, and juice that sucker up... measure peak to peak, then record values of 0.5 that and radical[2] times that peak as well... depending on the manner by which they "measure" rms, it'll be one of the two. ideally its radical [2] times peak, but oh well...

neomagus00 · June 2004

Originally posted by PoweredByDodge
try it out on the scope... find out transient specific AC resistance at a particular frequency (pick something around say 90 hertz or 100 hertz, as it should be in the "meat" of the power band), generate sine waves, record to cd, and juice that sucker up... measure peak to peak, then record values of 0.5 that and radical[2] times that peak as well... depending on the manner by which they "measure" rms, it'll be one of the two. ideally its radical [2] times peak, but oh well...

translation: find impedance of speaker at appropriate frequency, then calculate rms in two different ways.

paul - so you're using some sort of bandpass? or did i misread? can you throw up a diagram so i can see what a 3-chamber internally-ported design looks like?

Systems · June 2004

Put it in 4ft^3 ported(NOOOOOOOOOOO) tuned to 45hz with lots of port area.....tada

It'll be loud till it dies.....SPL **** machine, no SQ. Why would someone do that to a polk? For fun, and experimentation.

Oh yeah give it 1000w burps....:)

Airplay355 · June 2004

i agree with altec, that should make it pretty loud

exalted512 · June 2004

loud...for a day...lol
-Cody

Systems · June 2004

He never said how long:)

paul mx3 · June 2004

i never said i wanted to blow it.....although it could be fun the day before i fit my new idmax 12.....im after sq really but because in iasca sq competition you get points for every db over 100 you get up to a maximum of 35 points for hitting 135 db.....just wanted to know if it would be safe to try and push for the 135

exalted512 · June 2004

you could burp it to 135 im sure...it MOST LIKELY wont damage your sub if you only do it a few times....but im not making any promises...lol
-Cody

MacLeod · June 2004

You can bet that JL is putting out a good bit more than 500. JL amps are pretty underrated (as are most quality amps these days). Judging from tested power on other JL amps, Id say that thing is sending out 550 at least. The 300/4 is rated at 75x4 but delivers 90x4 according to Carsound.com's test of it.

paul mx3 · June 2004

Originally posted by MacLeod
You can bet that JL is putting out a good bit more than 500. JL amps are pretty underrated (as are most quality amps these days). Judging from tested power on other JL amps, Id say that thing is sending out 550 at least. The 300/4 is rated at 75x4 but delivers 90x4 according to Carsound.com's test of it.

at last someone who agrees with me about jl amps.....

MacLeod · June 2004

Dude, where have you been? Ive been getting hammered on the Car Audio & Electronics forum for months now for touting all the sonic goodness of JL Audio. JL has always been about my favorite brand in the car audio world and I especially love their amps, even more than their subs and speakers. Finally, an ally!!

exalted512 · June 2004

Originally posted by MacLeod
Finally, an ally!!

wonderful...:rolleyes:
-Cody

MacLeod · June 2004

I knew you would be pleased!

exalted512 · June 2004

Originally posted by MacLeod
You can bet that JL is putting out a good bit more than 500. JL amps are pretty underrated (as are most quality amps these days). Judging from tested power on other JL amps, Id say that thing is sending out 550 at least. The 300/4 is rated at 75x4 but delivers 90x4 according to Carsound.com's test of it.

they probably tested it 18 volts
j/k

-Cody

paul mx3 · June 2004

ive posted this before but here we go again for any none believers...

http://www.bbg-av.com/ZLinkFiles/AmpComparison.jpg

exalted512 · June 2004

ive never seen a bd1000 that bench tested that low at 12.8 volts, but ok
not to come off as an ****, but i really dont care what any amp can do at 10.5V because, at least in my vehicle, the voltage doesnt drop below 12, as soon as i add another battery and upgrade some of the wiring, it probably wont go below 13.3 or so
you can show me those numbers but they dont mean much, at least to me
and it still doesnt explain why theyre so overpriced

-Cody

Airplay355 · June 2004

you have to double the wattage to get a 3 db increase so the difference between 75 and 90 isnt that great.....atleast thats how it is in the HT world, idk if watts are the same for everyone tho lol

MacLeod · June 2004

Its the same in the car audio world too. I emailed JL Audio's tech support about the power handling on their XR 6.5 comps. Told him I was looking to put 125 rms to em. His reply was "they will handle the power but it wont be worth it. If you double the power it will increase overall volume by about 3 db but at the same time double the stress on the voice coil and speaker overall really shortening its life. We rate the XRs at 70 rms because thats where they will provide the most DB and best SQ. More power will not make them sound any better, just a little louder".

Thats fine with me, itll save me some money on a bigger amp!!

max db

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