Question for car-audio folks: boomy subwoofer

Ted Lee

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hi all -

i just bought a 99 4Runner.

it came with a pretty decent sound system (alpine stuff) that i can tell was properly installed (thick gauge wiring, excellent fuse protection, etc.)

so the sub is wired with a variable knob in the dash. if i want to increase the bass i can turn up the knob and vice-versa. the subwoofer is in the back of the truck. i haven't really checked it out in detail, but it appears to basically be a sealed enclosure with a single port. looks to be about 8"...probably 10" max.

the problem is that it's really "boomy". it has that kind of "rolling" vibrating bass that i don't really like. i'm more of a tight "punchy" bass kind of guy. if i try to increase the bass (for more punch) all i get is more boominess.

so, is there anything i can do to tighten it up?

thx!

ted
 

Jason Reich

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I will try and help but, I need you to help me out with more info. Get in the back and take a look at that sub. Is it in a ported or sealed box? what make is it? box size would help as well how long, wide and deep is the box? Is it an 8 or a 10? In cars or in your case trucks you get whats called "cabin gain" you can do things, like different tuning points or sealed vs ported enclosure, direction the driver is facing etc, to achieve different results. My personal preference is sealed in my car with minimum spec box, I have a single 12 inch and get plenty of punch.
 

Ted Lee

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hi jason -

thanks. i should have more info before i post, but you know how that goes.
i'll try to get exact details tonight. it's actually my gfriends truck...i'm just making the payments. (go figure...)

no clue on the brand. i'm positive it's ported (remember seeing it). not sure about the dimensions. i'd say it's about the size of four big and long shoe boxes stacked 2x2. i'm guessing, but i'll say it's an 8".

right now the port faces up, but it's shooting into those truck bed cover things you can pull to the end (to cover what's inside).
 

Jared_B

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Boominess is a typical flaw of the ported car audio sub box. You can try a few things with the current sub, or you can swith to a sealed box sub (much tighter and better response). Moving the current sub to a different spot in the hatch can make a difference, as well as which direction the driver/port is facing.
 

NickSo

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try stuffing it with some polyester fill (i think thats what its called)... it shoudl improve it some.. and also like jared said, switch to a sealed box (you can 'test' this by stuffing a tennis ball or a sock into the port hole to see how it sounsd)
 

Charles J P

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Also, check where the crossover is set on the amp if you can. I've seen car amps that can be crossed over as high as 250Hz. This is WAY to high in my opinion. Try setting it below 100Hz. The lower, the more likely some of the boominess will go away.
 

Ted Lee

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thx for all the tips guys. i really appreciate it...car audio isn't my forte anymore.

i'll research and let you know!
 

Tim Morton

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The one thing you can try is changing where the sub is firing. First place to try is fire it back toward the rear of the car. This will increase the active wave of the bass(allowing it to play lower, and louder), and in decrease any standing waves, which may reduce the boominess. You may be trying to turn the bass knob up too high, an 8" sub will only produce so much bass. Find out what this knob is actually doing, as a properly tuned subwoofer should NEVER ned to be level adjusted. is this an aftermarket stereo? Just wondering if this knob goes to an Audio Control Epicenter.
 

Ted Lee

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well, i took a look at the sub.

it's made by speakerworks. it says "single reflex band pass" on the side. it's 20x12x12. it has a single port which is now firing upwards (into the cover slide thing you use to hide what's in the back).

i think the first and easiest step will be to experiment with the port location. i'll try firing it towards the back and also experiement with sub location.

i don't think i have the knob adjustment thing cranked too high. i'm pretty sensitive to how bass sounds and i hate it when it overpowers the music.

i can't tell where the amp is!
although i haven't really looked too hard. i'll check to see if it has an xover adjustment. it doesn't appear that the head-unit does.

one thing i noticed is that the sub is accepting a speaker level input...not an interconnect like i originally thought. does that mean anything?
 

Philip_G

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my question is, what is that knob on the dash? is it the gain? if so you shouldn't adjust the gain for more bass really.. but it's tough to tell what exactly it controls
 

Jeff_Krueger

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The knob on the dash is most likey not a gain control but probably a bass control that boosts a specific frequency band. Many amplifiers come with this as an accessory and typically boost a narrow range centered around 40hz. With a ported box depending on the tuning using the bass boost can definatley make the boominess (sp?) get out of hand.

While placement may make some diffence, try plugging the port and seeing how that sounds. If you like that better you might consider building sealed box with the old driver or if you want a new driver. but check to see what kind of amplifier is in the system so you know how much power you have to work with.
 

Philip_G

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Many amplifiers come with this as an accessory and typically boost a narrow range centered around 40hz.
Ah, you'll have to excuse me as I'm still running my old soundstream amps from the early 90's :b I'm not up on the latest amp technology, though I think SS sold a "basslink" that did something like that, but I wasn't sure if it boost a freq range, or just pumped the gain.
 

Jeff_Krueger

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Yeah it seems to be pretty popular with the big sub amps but it seems a little gimicky to me personally, I prefer to have a headunit that has a variable sub level, that way if you feel like cranking the bass you are not throwing the tonal balance of the system off so much. Though anymore I like to just set it and forget it (no the sub not the rostisserie
)
 

Shawn Solar

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I would start by disengaging all bass eq's. tone controls loudness switch and on the back of the amp, they usaully have a bass boost @45hz or lower. Then turn up the volume to your daily driving level and set the bass to your liking. As said before try lowering the crossover point. voices should never come from a sub. That's my motto.

When you got that set turn the gain on the amp down. and any gain on the headunit(if there is one). Turn the volume up 3/4 of the way on the head unit. Or the point where the door speakers start to slightly distort. Then return to the sub amp and fill in the sub until properly balanced using the gain. Or when at the spl limit of the sub. whichever comes first. That should take care of any boomyness.
 

Walt N

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Bandpass sub enclosures produce a "one-note" boomy sound by design. They're very efficient and are good for scaring the neighbors, but the design is not the best for musical bass reproduction because of the narrow bandwidth reproduced. You might want to try a different type of cabinet, sealed or ported, using the same amp and driver you have now. It shouldn't be too expensive to change just the cabinet.
 

Ted Lee

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great info guys...thanks a lot!

i will be doing some more digging around with the wiring of the system...but probably not right away. my gfriend is already wondering what the heck i'm doing to her new car!


the head-unit (afaik) doesn't have any xover or gain settings. i'll be getting the owners manual for all the stuff soon. like i said, the sub is connected via speaker level connections...no subwoofer cable. i assume that means any adjustments are done via the amp?

i'll look around for the amp, plus try to follow the wiring of that knob in the dash to see where it leads. i'm assuming that there is only one amp in that truck, but i'm not sure.

right not the whole system is set to neutral. no boost (from the head unit) in the bass or treble. right now i actually find the knob useful. certain music sounds anemic, certain music is overpowering, and (every once in a while) it's kinda fun to just crank it. but i do wish i could set it and forget it.

as far as enclosures go, perhaps i'll try that down the line. i will try plugging the port and see what happens. right now i've got to remember it's her truck and she actually likes the way it sounds. oh well, sometimes ignorance is bliss!
 

Walt N

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If it's a bandpass sub box you don't want to seal the port. That's it's only outlet for sound.
 

Ted Lee

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ahh...good to know walt! :b

btw - does anyone have any good links for car audio type stuff in general?
 

Jeremiah

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Could it be that there is not enough power going to the Sub? I have a 12" in a small sealed incloser and it is hits pretty tight, not sure if it is the Watts or the box.
 

Ted Lee

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not sure how many watts i'm running. i haven't been able to check out the specs of the amp. but it feels like there's enough power.

i wonder how pissed my gfriend will be if i tear apart the interior...
 

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