sub box construction.

[NorCalChris]

whats better then a sealed box? whats some advice on building a sub box to hit hard? Ive seen people with bigs subs and amps and seen smaller subs and amps hit harder, as with anything its about efficiency, so let it rip. Whats your advice?

 

[dave92cherokee]

Back in the day when I used to mess with car stereo and subs everything centered on 2 things, what kind of music you listen to and do you want loud rattling bass or quality? For quality sound it would be sealed box so the subs move less and can react quicker, for loud then you want either ported box or bandpass box. If building one then I always built them to the air requirements for that sub and then used the port to tune the subs and box to their best frequency which usually falls in the 30's range.

 

[P1atinum]

What’s better is a relative term to what you think better sounds like. The ultimate goal for Sub boxes would be a Transmission line box; Flat response across all sub frequencies. But not practical in most applications and I have never seen one work in a car.
Lots of variables when building sub boxes.. Box design, Material, Equipment used, power, listening level. What the vehicle environment is like…
All boxes and speakers are optimal at a specific frequency then the performance degrades outside of that parameter.
BandPass boxes where the rage in the late 80’s early 90’s because they “hit” very hard. But only at one frequency around 60hertz.. so the music sounded like crap.
Ported boxes are also “hard hitting” but still at a specific frequency and drop off is steep, not as steep as the bandpass box but still pretty steep.
The reason sealed boxes are so popular is because they can play a much broader spectrum of frequencies with less drop off say from 40 to 120hertz.. Sealed boxes are considered much more musical.
Personally I like sealed boxes with 12’s which I tend to overpower and compliment with VERY GOOD mid’s

 

[GrimmJeeper]

check out the specs on your sub online and build a box to match the ft^3 your sub was designed to work best in. most people just grab a sub and stick it in whatever box they can get, it will work much better in the proper box.

small bandpass boxes work well in XJs because it's one big resonance chamber.

 

[littleblackxj]

Ported boxes can sound better then sealed IMO if you do it right. I tend to tune my boxes down to 27hz and have a large port area with a long port and it helps give the box a nice linear response curve down to 35hz, and drops off around 20hz (plenty low enough considering 20hz isn't audible by most).
If you are considering going ported and building your own box, which I highly suggest if you go the ported route, check out this website. It will give you the suggested minimum port area, as well as the port length and from there you can start designing your box. Just keep in mind that the area the port takes up does not count as the volume of the box, so keep that in mind too.
http://www.carstereo.com/help/Articles.cfm?id=31

Heres a little video of the last sub box I put together.
http://www.youtube.com/watch?v=UnbZoVjl4M8

 

[asp]

I say that the sub box style depends on what you're going for. If you're aiming for overall listening enjoyment, do a sealed box. If you want to set off car alarms and rattle windows, do a ported box.

Grimm is dead right about matching the volume of the enclosure to the mfg recommended size. You can cheat a little bit by using polyfill (it slows the sound wave down inside). He's also got a good point about cabin gain. I used to have a 12" JL in a properly sized sealed box in my XJ... It wasn't quiet.

I love a good strong response at 20Hz or so. Not only can I hear it (I've been tested and I have really, really good hearing), but you feel it. The problem is finding songs with clean signal that low in frequency. Most head units will output 5 Hz to 20kHz... The trick is getting a good response across the range.

As far as materials... well, how stealth are you looking to go? If you want to sink it into a cubby in the side of the xj, make it out of fiberglass. If you just want a box, make it out of 3/4" thick MDF. MDF has very good sound characteristics because there are no voids in it. It also happens to be cheap as compared to Russian birch plywood.

Positioning in the vehicle will affect how it hits. My 12" was pointed at the back hatch and that seemed to hit really well. I never experimented with any other options in my XJ.

Here's what I recently installed in my DD... Note that it's a hatchback - the interior is one open cabin just like the XJ. I've still got some kinks to iron out in it, but I like it a lot so far. Having the sub pointed up at the ceiling seems to be working well.

So, specifically directed to the OP: How crazy do you want to get with this? If you put in a big boomin' sub you're going to want to upgrade the rest of your system. I originally installed only a sub and kept the stock speakers. Guess what? It sounded like crap. So, decide how you want it to sound and how much you want to spend. I'll do my best to try to help you go from there.

Hope that helped.

 

[NorCalChris]

I have pioneer speakers in my doors. They were cheap and are only rated at 220. they arnt amped and they distort at high volume. I just Came across a set of mtx 10's and a kicker sealed box. I had an old jensen 460 watt laying around so I hooked it up and was impressed. It hits better then the 2 12's and a 1200watt amp in my ex's car. I dont want to build my own box anytime soon, these subs are fine with me, they could handl;e a more powerful amp, but this system hasnt cost my anything so Im not going to put anything into it. lol. I just had a few questions thats all.

 

[asp]

220 W peak or RMS? That's gotta be peak. Lesson #1: peak power handling doesn't mean squat. Go by the RMS value. Same with the the one in your ex's car. Are the speakers coaxials or components? Stock HU or aftermarket? Stock HU's send such crappy signal... If it's an aftermarket, they are amped. Most aftermarket HU's output about 10-20W RMS per channel, depending on the model.

I bet your ex's car was a sedan and the subs were in the trunk. That's going to change the sound a LOT. FWIW, 10's won't hit the low frequencies that a 12 can in the same configuration.

 

[P1atinum]

Lesson #1: peak power handling doesn't mean squat

This cannot be said enough.. Never look at anything that says Peak handling for any car audio component.. There is no industry standard when measuring audio components.

Go by the RMS value.

RMS is a good starting point but is very often overstated in audio components, same reason as above no industry standard.. The RMS value is optimal and based on whatever bench test equipment, tone generated frequency that provided the best results.
You can have two speakers with the same RMS specs sound completely different in the same system.

To the OP you it may be just a matter of matching the specs of the speaker and the box they are in. Can't just throw a set of 15's in a box and expect DB drag down the Ave.

 

[asp]

There is no industry standard when accurately measuring audio components.

I'll agree with that

RMS is a good starting point but is very often overstated in audio components, same reason as above no industry standard.. The RMS value is optimal and based on whatever bench test equipment, tone generated frequency that provided the best results.
You can have two speakers with the same RMS specs sound completely different in the same system.

I think that starts to get into the nitty-gritty of the frequency response of each driver and deal with less of 'how much power can it handle?' Most people start to lose interest right about here - never mind getting into time alignment or busting out the RTA.

To the OP you it may be just a matter of matching the specs of the speaker and the box they are in. Can't just throw a set of 15's in a box and expect DB drag down the ave.

Couldn't have said it better myself.

 

[GrimmJeeper]

I had 4 15" kicker compVRs (the silver poly cone ones) in my XJ in 07, in a custom built sealed 4 chamber box, my buddies used to call it the wall of death because it would turn your stomach with the radio half way up if the windows were closed

one trip to the desert and a hard hit put a stop to that, the weight of the magnets pulled 3 of the subs right out of the box. I decided I liked going fast more than setting off car alarms 3 blocks away, no more of that for me (in the XJ anyway )

i tend to lean towards JL amps if i have the coin, hifonics if i dont. hifonics aren't rated the same, my 1200w hifonics sub amp hit *almost* as hard as my jl 300.2, but i scored it used for 30$ neither brand has let me down in the past, but hands down JL has won for every sub and amp i've tried (not counting the jl w0 series)

 

[asp]

I'm no JL fanboi, but JL amps are great. They're small and very powerful while giving great signal. I have a the first generation 250/1 class D monoblock amp powering my sub and unless I was competing, I don't really know what I'd do with more bass.

There are a few other companies out there. I know that there's a member who works at a custom speaker mfg in Vegas. Their subs are pretty sweet looking.

I wouldn't say that JL is the only good company for subs, but they're one of the few well known companies whose products I like.

 

[srimes]

Boxes suck. Infinite baffle baby!

 

[GrimmJeeper]

I wouldn't say that JL is the only good company for subs, but they're one of the few well known companies whose products I like.

I agree 100%. I happen to love the look of the JL 12w7 though, the hidden mounting makes for a nice clean installation, and the excursion on them is crazy. in my DD I'm rocking a single hifonics zeus 12" sub I got on craigslist for 50 bucks, and an older JL 300.2 amp. It hits deep and gets loud, and it's got a pretty stiff rubber surround on it so its nice and punchy too, something a lot of subs 12" and up lack. That's one thing I liked about my compVRs too. The JL w7's hit that deep bass that will vibrate the teeth out of your head, but for tight punchy bass like rock music they show their weakness pretty quick.

 

[asp]

I agree 100%. I happen to love the look of the JL 12w7 though, the hidden mounting makes for a nice clean installation, and the excursion on them is crazy. in my DD I'm rocking a single hifonics zeus 12" sub I got on craigslist for 50 bucks, and an older JL 300.2 amp. It hits deep and gets loud, and it's got a pretty stiff rubber surround on it so its nice and punchy too, something a lot of subs 12" and up lack. That's one thing I liked about my compVRs too. The JL w7's hit that deep bass that will vibrate the teeth out of your head, but for tight punchy bass like rock music they show their weakness pretty quick.

I'm with you that the W7 looks sweet. I just can never get over looks if I don't like its performance. It would be like having a Ferrari and putting a 1.5L 4cyl NA engine in it - all looks, no function.

W7's do have insane excursion. A friend of mine used to own a sub that had 3" one way (6" total travel!!) excursion. He was trying to break 150dB with a single 12 in a sealed box. He got 146dB...

I'll have to take a gander at your Hifonics sub. Sounds like a good grab.

Unless you're competing in SPL I see absolutely no reason for more than a single sub - you can get all the bass you need for listening enjoyment out of a reasonably priced 12" in a sealed box being powered by a good amp.

My new 12W3V3 is still breaking in, but I'm really liking it so far. I've had it in a sealed box my VW for a little over a month. Lately it's gotten a lot punchier, which is something I love but it's stayed real tight. I should probably put polyfil in the box... I keep meaning to then don't.

 

[NorCalChris]

who on here competes or used to compete in sound comps?

 

[P1atinum]

I did a long time ago, SQ and SQ+ Pro 251 to 500 class. I have also built several cars that competed or I ran for customers, and was an IASCA judge..

A very long time ago, I have been out of the audio business for 10+ years and I don't know crap now, LOL.

 

[asp]

who on here competes or used to compete in sound comps?

I never have, but I might enter my first low key SQ comp with my car this summer.