my single cab box fail... and re do oppinions on box plz.

brian84corvette
10+ year member

CarAudio.com Elite
hello all.

I have a 90 chevy single cab 2500

pair of jbl gti 10's old school single 4 coils - no idea on rms of them

currently on a old rf 200a1 so each sub is getting bout 120w atm.

box is down fire - 3" between the subs and the cab floor - center consil box

round pvc tube ports - I screwed up thinking I could use three 1.6" id tubes at 8" long each to achieve 32.5 or 33 hz tuning. yes I hit the tuning - but choked off the pair of 10s low bass hits good and hard. anything in the upper bass range plays realley soft and un satisfying in this config.

pix during the construction:

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pix when I got it done - or what I thought was done until I realized I screwed up

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then I was told I needed to rip out the trio of small ports and use a 4" pvc pipe - tried to fit it behind the driver seat coming out of the box - but driver seat is too far rear wards for that to happen.

so this happened - what an ugly mess of fail on my part atm.

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hopefully I can do a little bondo work on the external port and smooth it in some what and paint it black like the rest of everything is. - all black paint is truck bed liner from rustoleum $43 a gallon at walmart

good part is it sounds WAY better than before

but I still am keeping the three existing 1.6" ports in the box.

when I sealed them up and played some songs - it did not sound as loud / good as when I left all the ports un covered. strange - as I thought id need to get those out.

anyhow - im a bit frustrated at the entire sub stage of this build - and my plan is to hook those subs up to my hifonics bx1605 @ 2 ohms should power the subs with anywhere from 850w to 1050w and will probly end up smoking them... wich will be sorta satisfying after all the bs this current build has put me thru.

on to the next one :

in this / my aplication so far - downfire box has not been good to me

so I drafted up this : a box for a single 10" or 12" sub same idea - center consil box

but with a standard slot port - and sub facing back cab wall up at an angle.

hoping for 1.75 to 2.0 cubes net for the sub - ported @ 35 hz

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but since ive had such a hard time with this build so far - before I end up making any more boxes for this dam truck - id like you guys to give me some imput on a box style that I can use to the fullest potential in the single cab truck....

so please post any insight to the new box build please !

this is the beast btw.

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today I got a 6ch crossover hooked up - so my highs and mids are good now - I was having issues ajusting low pass with them trying to use "bass blockers" but its all good now.

also took out the little rockford punch 200a1 mono amp - and tossed my hifonics bx1605d on the pair of 10s at 2 ohm

so they might be getting anywhere from 700 to 1100 w for the pair. truck has good electrical

testing it out - its amazingly more powerful now. all the ports are moving some serious air now - and the box plays the spectrum of bass better than before with the extra port in there. the extra power just give more thunder to the system.

hopefully I can manage my self enough to not smoke up those subs right away.

long term plans for the truck are : get rid of the 10s - and get a single 12" sub that can take 1500w rms @1 ohm

and re build a good / better designed box for it. downfire is apparently not the best for being an efficent box.

 
i got a single cab too bro. I have just one sundown sa12 and it sounds really good. My box is 1.8 cubes behind my seat with a 4'' pvc port. i was planning to do a box like yours since im getting bucket seats. I want to run 2 sa12z but im pretty sure there isnt enough space for them ported. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 
that port looks way to big for the sub. Prolly sounds like butt. Ported=one good freq. That is all good for spl, but if you listen to different types of music sealed will give you more or a range. If you wanna stay ported, recalc your port size for that sub. you can do so with some basic math based upon sub specs.

 
its a pair of 10" older jbl gti 10s - not a single sub

and I did have one of the 10s in a small sealed box that was .6 I believe and it did sound good - but not loud

but again - loud for me is coming from my old car - the 84 corvette running a 18" off 1500w in the rear hatch that was so brutal it would give you blurry vision

I highly doubt I have the room / keeping both bucket seats - in this truck to get that serious again - but id like to get the most I can.

thats why I hacked up the box in there now to stuff in that external port

with the increased power im feeding the subs now - they seem to slam alot harder.

so until I come up with proper $ to fund a good single 12" sub to build a better designed box for then ill just have to rock out with whats there now... wich aint so bad off the increased power to the subs....

but doing construction work - definately ***** round this time of year. no body realley is replacing windows and doors - is what I do for a living - along with installing / servicing hurricane shutters.

 
Trunk is anything but a beast. Looks like a car with a bed on it. If it ain't a Ford it ain't a trunk. //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 
that port looks way to big for the sub. Prolly sounds like butt. Ported=one good freq. That is all good for spl, but if you listen to different types of music sealed will give you more or a range. If you wanna stay ported, recalc your port size for that sub. you can do so with some basic math based upon sub specs.
I thought port size was related to box size, not sub size. Also with the right tuning ported will sound just as good as sealed, and be louder

 
Ported=one good freq. That is all good for spl, but if you listen to different types of music sealed will give you more or a range.
A low tuning solves this problem, and allows you to be louder than a sealed box from 20hz and up. Not everyone builds 35-40hz tuned fart boxes...

 
A low tuning solves this problem, and allows you to be louder than a sealed box from 20hz and up. Not everyone builds 35-40hz tuned fart boxes...
35hz is a "fart box"? Please explain that one. Anything below 30hz is a waste.

 
35hz is a "fart box"? Please explain that one. Anything below 30hz is a waste.
Yes, in most cases 35hz gives you a very exaggerate peak in the low 40's, probably around 6db higher than it'd be at 30hz in the same box. Obviously this is box and sub dependent, but a 6-9db difference from 45hz to 30hz is not uncommon at all with that kind of tuning.

Why would anything below 30hz be a waste? If I can still get the response I need up top, then why not allow myself to extend lower while smoothing out the response at the same time? This obviously isn't the way to go if you're looking to put up numbers to impress friends with 40hz songs, but it's far from useless IMO. I'll never tune above 30hz again.

 
Yes, in most cases 35hz gives you a very exaggerate peak in the low 40's, probably around 6db higher than it'd be at 30hz in the same box. Obviously this is box and sub dependent, but a 6-9db difference from 45hz to 30hz is not uncommon at all with that kind of tuning.
this couldnt be more true. My current box is tuned around 35 on a single Treo 12, and is VERY peaky. I dont know what hz, but I think somewhere from 41-44hz this box absolutely pounds, like unusually loud based on the power ran to it...everything else is basically inadeqaute for my needs...the slope off down below 35hz seems very sharp, which I hate. Conversely, my Treo 15 at 30 hz did not even seem to have a true peak as the slope off both ways was much smoother... 30hz >anything higher

 
the slope off down below 35hz seems very sharp, which I hate. Conversely, my Treo 15 at 30 hz did not even seem to have a true peak as the slope off both ways was much smoother...
ding ding ding! The key, for actual music listening, is to not have a peak, to not have to mess with your gain or sub level based on which song you're listening to, etc. I haven't messed with my gain setting or sub attenuation on my HU in months...it just sounds good on everything. The response curve is spot on to what I want, so all I need to worry about is level matching with my front stage, which only has to happen on a few select cd's that seem to have recorded their bass at higher than normal levels.

 
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brian84corvette

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