Getting more low end from 15" L7..

[helotaxi 5,000+ posts]

The 4 dB peak at 48hz from the current ported box is why the sealed box was not satisfying to you.

How much space do you have to work with?

 

[SQBubble 10+ year member]

The 4 dB peak at 48hz from the current ported box is why the sealed box was not satisfying to you.
How much space do you have to work with?

max dimensions:

15"height

38"width

23"deep

 

[SQBubble 10+ year member]

The 4 dB peak at 48hz from the current ported box is why the sealed box was not satisfying to you.
How much space do you have to work with?

so i had to make it larger?

 

[helotaxi 5,000+ posts]

5.8 tuned to 30hz will give you a 5dB peak at 40hz and a 3dB down of 25hz. Loud and low. It's going to take a big box to get low. No way around it.

A 6cf sealed box will play flat to nothing and will give a 3dB down of 30hz.

Either box will fit in the space you have to work with.

 

[SQBubble 10+ year member]

5.8 tuned to 30hz will give you a 5dB peak at 40hz and a 3dB down of 25hz. Loud and low. It's going to take a big box to get low. No way around it.
A 6cf sealed box will play flat to nothing and will give a 3dB down of 30hz.

Either box will fit in the space you have to work with.

//content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif 5.8!!!!!!!!!!!! wut about the high end with that big of a box...??

wouldnt it sound muddy and weird above 50-60hz?

 

[yacob.naif 10+ year member]

ya, l7 15's sound muddy and wierd above that anyways

 

[CJL 10+ year member]

I got my 12" L7s tuned to ~30hz and songs like Young Jeezy's Soul Survivor, Lil Scrappy's No Problems gets hella loud for me and the song Bass I Love You the lowest note shakes my whole sterring wheel.

 

[helotaxi 5,000+ posts]

//content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif 5.8!!!!!!!!!!!! wut about the high end with that big of a box...??
wouldnt it sound muddy and weird above 50-60hz?

Regardless of what you want it to do, it's still a SUB woofer. It isn't meant to play that high in the first place. That said, the higher frequency response isn't affected as much by the enclosure. It's more a factor of cone breakup and attenuation due to voicecoil inductance.

If you want low and loud, you have to make a trade. The trade is box size.

 

[SQBubble 10+ year member]

alright so till wut freqquency u think itll play good in this box>?

 

[helotaxi 5,000+ posts]

Above 80hz the sound starts to become directionalized and you will realize that it is coming from behind you. If you don't care about that, you can get up to 150hz with MOST (not all) subs without problems. Some will let you get a lot higher, but these are usually sound reinforcement/monitor type woofers pressed into car sub woofer duty.

The inductance of the voicecoil will cause the sub to begin to roll off at about 700hz with the coils wired in parallel (I'm assuming coils wired in series for the Le value given on the AA website). Cone breakup might cause some distortion issues at a freq lower than that.

 

[singlesubsetup 10+ year member]

//content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif 5.8!!!!!!!!!!!! wut about the high end

Huh?//content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif//content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

 

[bikinpunk 10+ year member]

I have a 12w7 ported and tuned to 28hz in a 2 cubic feet box. Songs like Soul Survivor get REALLY loud, but sound very good in the SQ department. I had a tough time deciding on what to tune to, but knowing I wanted a little more "boom" to the bass was the deciding factor. My previous sealed box sounded great quality-wise and had very precise punch, but it just didn't achieve the boom, so I went ported, tuned low to keep that sq, but get the boominess I was looking for. My box sounds GREAT. It's dead-on accurate, and if it were "louder" it would be pointless, but was my logic wrong?

There are a couple songs (literally like 2 or 3) that don't play right, and I'm not sure what it could be. Mainly becasue I don't know the frequency of the bass sections. One in particular is "hood rich" by the big tymers. For some reason that song always sounds like I've lowered my bass setting to 0 and the bass is barely audible, and doesn't make much of a wake in the sound pressure department either. Can you offer some advice on what this could be?

I'll be building a new box soon to go in my new car, so this topic saved me from making one of my own similar to this.

 

[helotaxi 5,000+ posts]

Does the sub move on those particular songs? If it is really moving, the bass notes are lower than the tuning of the box and the port is working against the sub and cancelling the output. If it is barely moving, it is a higher freq than the Le of the sub wants to let it play.

Some other possibilities are that your crossover or subsonic filter got messed up. You also might have miscalculated and mistuned your enclosure resulting in a higher tuning and thus a higher low end rolloff. It could also be that that particular is right at the maximum point of impedance rise for the enclosure resulting in the amp's inability to really drive the sub at that particular freq.