db drag today
 

well, my first compitition in car audio today and I am convinced you cannot pull high numbers in this car. I have a soundstream tarantula t4-15 pushed by a soundstream PCA1500D. My car was measured at 135.6 db. i should be getting higher numbers with that setup. everything with the sub box is exactly soundstream specs, but it just seems that it just cant pull enough air to feed the sub. I am so frustrated right now that i just wanna take everything out and say screw sound comps. what is the highest number anyone has pushed in their 8?

-Steakboy

no idea how to check
how would I go about doing that other than competing and making a fool of her :)

I would like to see a pic of this box and woofer in your car.... Because if it is built to specs (4.25 cu/ft vented) I can't think of too many ways you can have it in there with still having enough airspace to feed that woofer...

do you have a pic?
have you done anything with "the big 3"
have you done anything with the HU?

what exactly is your setup?

Hey guys whats up im still installing my setup right now but soon it will all be in and ill get some numbers. I have a JL audio cleansweep running to a PG 500.4 ti for my highs then two JL audio 500/1's pushing two JL Audio 10" W7s. I also have a shit ton of Dynamat. I noticed something when installing the dyanamat. In the trunk behind the left and right carpet side panels there are two vents, fuck that I covered em up with dynamat. I'm convinced that the key to spl in this vehicle is to keep the space open where air can flow through the rear between the seats. I'll get you some pics asap. Peace

The key to SPL is tuning the box to the loudest resonant frequency. If you build a box to exact Soundstream specs, it is going to be a box designed to give some good tonal response and good output levels. It is however definitely not going to be something that is going to do well against a pure SPL type box. If your box is tuned to deliver output to 32 hz or so, and the SPL box is tuned for max output at 67hz, that is going to make a huge difference in the lanes at a SPL competition. The downfall here is that a pure SPL system is going to sound like shat for you to listen to on a daily basis. Decide what it is you are after, good sound that can play to a respectable level (which you have) or pure SPL (which you do not have).

The two rear vents are so that the pressure can escape from the vehicle when the air conditioning or heating system is used. If you value your fan, you will be unblocking those vents that you sealed. Go turn the heater fan on and wait a bit, see if it sounds different or laboured to operate. This is what happens when the cabin cannot release the pressure it is being fed by the climate control system. End result is a blown climate control fan.

^^They also relieve pressure to aid in door closing.

here's the thread that i showed my box for the first time, it has a few pics

https://www.rx8club.com/series-i-interior-audio-electronics-24/soundstream-t4-15-8-a-75494/

thanks for the help guys

-steakboy

I actually had an idea, please tell me what you think. the back of the box sticks up past the pass through a bit. If I put a port into that area, do you think it would be able to draw enough air from inside the cabin to help the sub? sorry, no pics at this time of the particular area in which im referring.

-Steakboy

I must not be getting the picture. I am assuming you have tried it w/ the passthrough door removed. If it what I am picturing, this would give you your answer.

Subs dont draw air at all. In fact the less air space you have is usally better. A port is only to delay the sound from the backside of the woofer so that you hear it at the same time as the front side. Im going to meter my car tonight with a single 10" w7 i let you guys know what happens. Oh yea my fan does suck with the vents closed but if i put it on recirculate it seems to be fine. And my ears pop a little when i close my doors.

Spl
 

My car hit a 134.6 witch is about what i expected to hit. Agian thats with a single 10w7 sealed powered w/a 500/1 in a sealed box tuned to the spec hz. level for sound quality my sub is in the recessed part of the trunk right now facing the drivers side. Once i get both subs and amps put in it should be much louder.

Steakboy, the reason i want my passthrough open is to let pressure from the sub into the cabin rather than to feed air to the sub. Idealy you would want your subs to face the rear of the trunk and sound waves would bounce off of that twards the front then off the windshield to give you peak spl.

This is misleading. Depending on what you mean by "less air space". If you are referring to "air space" inside the box, smaller is NOT better if you go below what the woofer is designed for. This is definitely not correct if you are refering to "air space" outside the box (i.e. inside the trunk). If a small area is totally sealed and there is no where for the pressure to go, it will find the path w/ least resistance. In the case of our small trunks.....probably going to be the speakers in the rear deck. If it does not directly blow the speakers, it will definitely degrade the sound quality.

Yes, I have my passthrough open to allow the pressure from the sub through. As you can see from the pictures I linked to, the sub is facing directly up against the trunklid. Unfortunately that is about all you can do with a 15 in sub that requires a 4.25 Cu. Ft. box. But here's the problem with the passthrough I doubt yopu have; my box is so large, that the passthrough opening is about half of the size it normally is. soon I'll be taking to the guys who designed the box to have a look at it and possibly redesign it. I don't want that to be the solution because I love the look of the box (As does many people). Maybe I'll try the other spec (high fidelity instead of high output) box because it is smaller. I dunno, I'm kinda dumbfounded and frustrated and even almost ready to just remove it all for now and concentrate on other parts of the car.

-Steakboy

i was referring to air space in the car. And i agree on the rear speakers to help that im enclosing the back side of the speakers and i remove the passthrough cover when i plan on turning it up alot.

steakboy i wonder if a sealed smaller box facing the rear with the passthrough fully opened would by louder tough to say i wanted to do ported but it was just to tough to make it all fit. Im still wondering how you got all that in your trunk?

From what I was told, it was pieced in. It was the only way.

-Steakboy

Well man your system is the best i think ive seen on the forum so far keep me updated!

Finally
 

Got both of my dub 7s in just in time for a bass comp. now i need to take them back out and do some fiberglassing. Well let me know if any of you are louder but my best yesterday was a 142.0

thats an awesome push. with a little tuning and letting the subs break in, you should be able to bump a few dbs

-Steakboy

hopefully I may go to a single sub ported due to voltage issues

what company sub are you gunna use? what size?

I wanna change mine up, but I love it soo much. It gets alot of attention too, so I'm torn.

-Steakboy

that's a big enclosure. my best official yet 146,7 on termlab using a vented enclosure 120L. Autotek MX5000 amp. 2 X 12'' C.V vmax subs. @ 1 ohm. ''when 8's get abused'' damn i miss db drags....

Please tell me that when you're driving around in your car you are not getting even remotely near those volume levels. Aside from the fact that some of you are getting past the threshold of pain you are doing incredible amounts of damage to your ears.

I've been told my 2 10's are probably in the 145 to mid 150 range, but no official numbers yet. Maybe later on this year I'll take it through the lanes :)

And in most spl drag events I know of they either force you to wear ear protection or force you to stay outside the vehicle while it's cranked up.

i definetly do'nt drive around with this (SPL) set up. tried it once 4 fun, tuned it at my shop as i have a db metre. reasons why not 2. (1) weight, (2) harsh certain frequency tuned bass, (3) no boot, (4) looks terrible.

what subs r they?
the subs can probably do the number in the right application... but can the 8? take ur back seats out totally and fire the subs into the car, with the correctly tuned vented enclosure, batt and amp power u will maybe get a 150. i personally would'nt use a 8 4 spl applications this extreme.

he's got soundstream refrences. i may be going to the same.

-Steakboy

a buddy of mine's focus:

http://myspace-253.vo.llnwd.net/0132...28455253_l.jpg
http://myspace-510.vo.llnwd.net/0132...28456510_l.jpg
http://myspace-033.vo.llnwd.net/0132...28457033_l.jpg
http://myspace-487.vo.llnwd.net/0132...28457487_l.jpg
http://myspace-486.vo.llnwd.net/0132...28458486_l.jpg

I think it pushed a 154 something

-Steakboy

they're 8's made by elemental design. he ended up blowing a bunch of those subs. he took it all out now and is working on another setup, but i havn't seen it yet.

You'd be surprised how hard it is to increase db up that high. to put it into perspective, there was a truck there with 15 15's pushing 162.

-Steakboy

At that level it is difficult. the focus is so neatly done, nice! reminds me of my 1987 nissan with a wall housing 4 12'' pioneer tsw306c 1000w woofers running 2 powerbase d5000 amps in tandem @ 18v but in a vented enclosure pushing a 154,5 official best. why doesnt ur friend do away with 4 subs and go vented? he'll climb 2 - 3 db's at least... is he running std voltage or higher battery set up looks more than sufficient? ur car steakyboy, r u firing the subs into the cab or back?

backboard/parcel shelf still in? box vented or sealed? amp getting enough battery power? what guage cabling? hope i can help cos i've managed 2 build the loudest official 2 x 12'' sedan in SA @ a internationally judged enent pushing 152,5 so i got some ideas...

I have a single 15 firing straight up. Look at the first post, I think there's a pic of it

-Steakboy

EDIT: Ooops, it's not, so here it is:

http://venus.walagata.com/w/steakboy42/IMG_6373-1.JPG

The box is the spec size for soundstream. the amp gets plenty of power and doesn't even get hot. The only reason why I get lowish numbers is simply the amount of air getting into the cabin. I'm going through a very small opening because of the box size.

im sure i can help the idea is better than firing back blocking more air flow, 1st those power cable, batt specs? and is the amp a 1/2/4 ch. sub dvc/svc? do u drive with ur back arm rest out?

The amp is a soundstream PCA1500D. max power is 1500Watts. the battery cable is 2 GA I think. it is a monoblock amp. The sub is a Soundstream Tarantula T4-15. 1000 watts RMS, 2500 Burst. The box itself is 4.25 cu/ft with 3" X 3" Ports. I like to drive with the passthrough out usually, and it's definately out when doing a comp. I'm pulling off the stock battery with no or very little dimming.

-Steakboy

dude the setup is nice...but if you want to win spl you should take out the back seat make a baffle board across where the seats were. and put three of them subs facing directly into the cabin. if you want to win spl....or unless your trying to win a specific class of spl. 136 for 1 15inch sub isnt bad. but if you want to make heart skip beats its gonna take a bit more. and a setup in the trunk isnt gonna cut it.

plus do you even have capacitors?? upgraded altenator?? everything dynomated?? and i mean everything....firewall, doors, roof, ...did you strap down the trunk lid?? you may not think your drainig power just because your lights dont dim that much but you may be down around 10 volts...and if your amp is rated 1500@ 14.4 volts it may only be pushin 1000 if that.

if ur sub is a dual 4 ohm sub and is wired up in parallel, ur only using half the power of ur amp. so either u need 2 get a dual 2 ohm sub or recoil ur s.stream dual 2 ohm 2 make that amp work. ''or'' another s.stream sub dual 4 ohm then the amp will b running at full power. then u can run the 2 firing in 2 the car with the seats out. but if ur gonna run 1 sub the best would b 2 fire it back with a vent with the seats out so it can hit the back wall of the car and deflect back past the box and into the car. the dynamat u can get away with 4 now would'nt bother with a cap, rather invest in a strong battery or two. all depends what class u wanna fall into as RICKY356 said. firing into a car u haved 2 have at least 2 subs vented and lots of power 2 back u up. firing back u can do with 1 sub or 2 if there is enough space for the bass 2 come past the box in ur case not, if u had 10''s it would b perfect. firing up in ur case 'no' unless u had no back board and spkrs etc., in hatch backs perfect. hope this info is of use.

Like I said before, I'm gunna be changing it up. I'm gunna leave the cabin of the car as stock as possible (no removal of seats).

As it is, the setup is nice for 2 reasons.
1) it looks amazing and is very eye catching.
2) it sounds very clean for every day use, and can get decently loud.

the setup sux for 2 reasons.
1) it wont win class comps.
2) i have no trunk.

All of your advise is great and appreciated. I will take all of it under consideration when I redesign my system with 2 reference 10's.

BTW, Phat8:
The sub is a dual 1-ohm sub. actually, here's the specs:

Soundstream T4-15 15" Dual 1-ohm Subwoofer
RMS POWER: 1000 Watts

* 15" Cast Aluminum Basket Woofer
* Dual 4-Layer, 1-ohm Voice Coils
* Cloth Laminated Paper Cone with MD6 coating
* Stone Gray Finish with Diamond Cut Edge
* Hi Arc, High Excursion Surround
* Chrome Plated Back-plate
* Low Carbon Top and Pole Piece
* Triple Stacked Magnet Structure
* Vented and Extended Pole Piece
* Black Progressive Roll CONEX Spider
* Woven Tinsel Leads
* Gold-Plated Binding Posts
* BAEISV Hybrid Voice Coil Former
* C- Lock Rubber Gasket
* Rubber Magnet Cover
* VOICE COIL DIAMETERS: 4.0"
* MAGNET WEIGHT: 250 Oz.
* FREQ. RESPONSE: 20 - 1k (Hz)
* Fs: 34 (Hz)
* Qes: 0.449
* Qms: 3.722
* Qts: 0.401
* Vas: 2.08/58.77 liters (Ft3)
* Xmax: 0.551"
* SPL: 91dB
* HOLE SIZE: 14.25"
* WOOFER DEPTH: 8.25"
* RECOMMENDED ENCLOSURE: Ported 4.25 (Ft3)
* RECOMMENDED ENCLOSURE TYPE: Vented
* AEROPORT DEMENSIONS: 3" x 3" (Two)

-Steakboy

i think your using your sub effieciently for the volume your getting. but if you want to win spl??? i mean those guys build there cars around there speakers. the 8 s to nice for that. if you get those references compete for sound quality.

I agree. U either want spl or sq. this is my way of getting the best of both. The sub u got being dual 1 ohm is not the ideal configuration cos if it's a dual 1 ohm if u parallel it will basically b a dead short, which will keep ur amp going in to protection or even blow. so u series it being 2 ohm if u running a monoblock u using half it's power being a 1 ohm stable amp probably why ur lights do'nt dim much. If using a 2 or 4 ch amp, bridged the amp will also do as said cos the amp sees 1 ohm. The best advice to get bass into your 8 with out removing seats and still having a good looker is if u do change ur set up... get two 10''s or 12''s and build a enclosure as close to the sub as possible horizontally and vertically just make it pretty deep to get ur required volume. positioned behind the seats facing the back of the trunk with a sub on the far left and far right with a opening in the centre the size of the opening where the clip out panel is. doing this u'll b creating a loading effect in the trunk and the bass will build up and reflect through the opening and into the cab. now ur probably blocking a good portion of the opening. tried and tested, works great and the frequency coverage is good. keep me posted when u get ur new subs. :)

same advice i gave above... hope it helps, let me know.

will post pics of my install soon, currently busy on it...