DiyMobileAudio.com Car Stereo Forum banner

1 - 20 of 32 Posts

·
Registered
Joined
·
78 Posts
Discussion Starter #1
Hi Guys,

I have 2 JL 12w3v3's (4 ohm single voice coil) in a sealed box running off a JL Slash 500/1. The subs are wired in parallel so the amp sees a 2 ohm load. I made the box to JL specs as far as the enclosure size for each sub. I have the subs crossed over at about 65Hz through my Bitone. I'm hesitant to go ported because I don't want the sound to be "boomy". I'm an amateur at this and I don't have the resources or time to play with different enclosure types and port configurations. The current sound quality is fine for me, but I'd like it to be louder at times. Raising the crossover point is not the solution for me. My other speakers reproduce the higher frequencies to sound levels that I'm happy with. I'm considering going to a larger amp, but I'm concerned about too much power for these subs.

Has anyone used an 800 watts or more mono to a pair of these? Will they hold up at 65Hz with that much power?

Any experience you could share is appreciated.

Thanks,
Tom
 

·
Registered
Joined
·
78 Posts
Discussion Starter #2
Any input?
 

·
Registered
Joined
·
1,665 Posts
If you design the ported box correctly, it won't sound boomy. How much louder do you want them to get?

Nice car, by the way ;)
 

·
Registered
Joined
·
78 Posts
Discussion Starter #4
Nice car, by the way ;)
LOL! The G8 just went back yesterday. It was a 3 year lease. The new ride is a grand cherokee. It's another lease so I have to be gentle with the modifications.

I'd like it to be 50% to 100% louder, but only at certain times. The bitone allows subwoofer volume control so I can use that to lower the sub's output if it gets to be too over-powering.

I don't want to blow a sub. The JL literature shows that the subs could handle 400W - 500W rms, but the literature doesn't say at what frequency.
 

·
Registered
Joined
·
1,665 Posts
No, JL says that 400-500W is in the danger zone. You may be able to do it just fine as long as you've got the proper subsonic filters and you're playing musical content that does not keep the subwoofer at constant full power.

Honestly, my suggestion is to port them or to get better subwoofers. While the W3 is not a bad sounding subwoofer and will get loud enough for most people, they are really not a very high output driver.

If you port them, you might get what you want. If you port them correctly, they will still sound just fine.

P.S. total downgrade on the vehicle :p
 

·
Registered
Joined
·
12,054 Posts
I don't want to blow a sub. The JL literature shows that the subs could handle 400W - 500W rms, but the literature doesn't say at what frequency.
x2 on what DR said.

btw power is power. 400W @ 65 hz will create the same heat as 400W @ 40 hz, 30hz, 20hz..............being able to handle it mechanically is another subject. since you get more excursion at lower freqs, i would not worry about 65hz.
 

·
Registered
Joined
·
78 Posts
Discussion Starter #7
No, JL says that 400-500W is in the danger zone. You may be able to do it just fine as long as you've got the proper subsonic filters and you're playing musical content that does not keep the subwoofer at constant full power.

Honestly, my suggestion is to port them or to get better subwoofers. While the W3 is not a bad sounding subwoofer and will get loud enough for most people, they are really not a very high output driver.

If you port them, you might get what you want. If you port them correctly, they will still sound just fine.

P.S. total downgrade on the vehicle :p
http://mobile.jlaudio.com/pdfs/11415.pdf
The spec sheet on page 2 says 500W continuous. The gray to black chart thing on page 3 is useless.

I've had these subs for a few years. I've heard many others and I just find it really hard to compare SQ because it varies so much from install to install. I'm fine with the way that they sounded in the G8.

I know that porting for higher output is the way to go. My concern is porting them correctly (tuning the size of the box) for the peak where I'm going to like the sound. I've seen the calculators online, some you buy and some are free, but I really don't know what frequency I'd want the sweet spot to be. I've done enough reading to know that the resonance frequency is going to vary from car to car. The Jeep with it's big open cabin, might BOOM too much for my taste regardless.

I wasn't happy giving up the G8. I had a GT and there was a guy selling a GXP on E-Bay that I went to look at. Nice car, but between the snow and the rain here I needed to make the change for my daily driver.
 

·
Registered
Joined
·
78 Posts
Discussion Starter #8
btw power is power. 400W @ 65 hz will create the same heat as 400W @ 40 hz, 30hz, 20hz..............being able to handle it mechanically is another subject. since you get more excursion at lower freqs, i would not worry about 65hz.
Your point is well taken. I meant the mechanical side of things. I wish the ratings on page 2 of the link in my previous point were shown at a given frequency. Most of the component speaker manufacturers will provide RMS ratings at a given frequency.
 

·
Registered
Joined
·
12,054 Posts
you could always just build it to the JL spec on that .pdf :p

30hz tuning should sound nice. if you want it modeled, XR on this site will do a model for ya. winISD is a decent modeling program too and its free.
 

·
Registered
Joined
·
1,665 Posts
Fair enough. Admittedly I was going by that image thingy.

If you're listening to real music, not bass test or bad rap, then tune your subs for 35Hz (or even 40Hz) or so - and you must set a subsonic filter at the tuning frequency as well. Seems like 800w should be safe for them. Going from 500w to 800w will only give you a gain of 2dB. You will gain more from porting them. Or you could do both.

By the way, I almost dumped my G8 for an AWD car. I hated the traction basically all the time. I've got the GT Sport. The stock Bridgestone tires sucked in all conditions, and I just assumed that it would suck in snow. Though I did drive it in snow on the stock summer tires once - about 1cm of snow. Didn't know it'd be snowing and I happened to be out when it started. Barely made it home. I actually tried to park it at my cousin's house which has a driveway with a TINY slope of no more than 10*. The thing started sliding down the hill!

I put Bridgestone Blizzak WS-70 winter tires on it and it's honestly almost as good as my Audi A4 Quattro was in the snow. It's AMAZING. I drove a Camaro before and I had Bridgestone RE-960AS (some of the best AS tires) and it was barely adequate and I didn't quite feel safe in it. But with these winter tires, you would have no idea that the car is RWD. You'd believe it were AWD if I told you so. Honestly.

Also, my Continental ContiExtremeContact summer tires now are WAAAAAAAAAAAAAAAAAY better than the stock sport tires.
 

·
Registered
Joined
·
12,054 Posts
Your point is well taken. I meant the mechanical side of things. I wish the ratings on page 2 of the link in my previous point were shown at a given frequency. Most of the component speaker manufacturers will provide RMS ratings at a given frequency.
I have never seen speaker ratings at given frequencies. like I said, power is power. if you give a speaker 100W, it will dissipate 100W. (not taking impedance into account) of course most speakers dont get a full 100W 100% of the time, but you get the idea.
 

·
Registered
Joined
·
78 Posts
Discussion Starter #12
you could always just build it to the JL spec on that .pdf :p 30hz tuning should sound nice.
:)

That's what I mean. It's about trial and error and the vehicle. What box frequency is optimum for vehicle? We won't know until we start to play around with the box configuration. While I love the hobby, it's tough on the wallet. Building a box is time and money. I live in a condo so I don't have a garage or a basement. I could make use of a friend's place and tools for a weekend, but asking him to do it more than once is a stretch.

Thanks for the heads up. I'll look into the software. Maybe I can find a way to set this up so the ported box has a similar peek to the current sealed box.
 

·
Registered
Joined
·
78 Posts
Discussion Starter #13
I have never seen speaker ratings at given frequencies. like I said, power is power. if you give a speaker 100W, it will dissipate 100W. (not taking impedance into account) of course most speakers dont get a full 100W 100% of the time, but you get the idea.
I wasn't exactly correct with what I said. Take the HAT L8's for example. On page 6 of the manual is shows that the minimum cross over is 40Hz at 24dB. It also shows that the max power is 215 watts at that rating.
http://www.hybrid-audio.com/Legatia L8V2.pdf

I do get the idea of what you're trying to get across. My issue is damaging the cone mechanically by forcing the cone to move too far by driving it with too much power at a given frequency. The HAT spec sheet provides a guideline for that and I wish I could find that same info for my subs.
 

·
Registered
Joined
·
78 Posts
Discussion Starter #14
If you're listening to real music, not bass test or bad rap, then tune your subs for 35Hz (or even 40Hz) or so - and you must set a subsonic filter at the tuning frequency as well. Seems like 800w should be safe for them. Going from 500w to 800w will only give you a gain of 2dB. You will gain more from porting them. Or you could do both.
Could you talk a bit more about the subsonic filter? What is it's purpose?

I always thought of the subsonic filter as a high pass for the sub channel. Since the bitone is fully active, I have the ability to set a high pass for the sub channel, but I've just never done so.
 

·
Registered
Joined
·
3,033 Posts
If you want a ported box design that will do what you want it to do then I suggest contacting this guy...

PWK Designs

I believe his fee is $50 for a design.

Also, XtremeRevolution does free box designs on here. He takes into account cabin geometry & things like that.
 

·
Registered
Joined
·
324 Posts
When you say you'd like it louder at times...what are those times? Is it when the windows are up/down, when playing a certain kind of music, or do the subs not keep up or stay linear with the rest of the system when you start to crank it?

I ask b/c in your sig you state you're using the OE radio. I'm not familiar with that Pontiac/Holden thing but do know many newer GM radios start to screw with the bass response when you crank things up and/or start moving. That could be your problem in which building a ported box or doubling your power will probably gain little. In addition, if you're listening to older rock stuff, there isn't a lot of bass to begin with.

A pair of 12W3's running off a 500/1 should beat you up pretty good. Have you verified with a battery that the subs are in phase? Another check; play a familiar song with both the trunk open and closed. If it's louder with the trunk open, try flipping the pos. & neg. wires going into the box and/or facing the subs in the opposite direction.
 

·
Registered
Joined
·
78 Posts
Discussion Starter #18
Can you explain the reasons why a subsonic filter would be set to the frequency of the box?
 

·
Registered
Joined
·
78 Posts
Discussion Starter #19
If you want a ported box design that will do what you want it to do then I suggest contacting this guy...

PWK Designs

I believe his fee is $50 for a design.

Also, XtremeRevolution does free box designs on here. He takes into account cabin geometry & things like that.
Thank you. I'll look into both of those suggestions.
 

·
Registered
Joined
·
12,054 Posts
Can you explain the reasons why a subsonic filter would be set to the frequency of the box?
you really only need it for a ported box. you will NOT set it for the tuning freq. there is no exact science to say where you set it, but with a ported box you WILL want it set.

the reason is because a ported design will unload (make the speaker move ALOT) below the tuning freq. if you have your port tuned to, say, 40hz, then you would want a SSF around 30hz. anything less and the sub would beat itself silly. since you tuning more around 28hz, then a SSF of around 20-22hz would be fine. you just dont want the sub responding to stuff lower than 20hz or it could be damaged.

this is not the case with sealed since the excursion of the speaker is only controlled by the volume of the enclosure. there is no tuning.
 
1 - 20 of 32 Posts
Top