So we finally got a chance to play with the car more. So we walled the box off the box to the trunk using mdf and "L" brackets to secure wood to box and car. And used gorilla tape to seal cracks. This is a test to see if results are worth doing a nice looking wall or not.
Gain from walling off was .4-.5db gain which put us up to a 150.3db consistent with 2000w clamped power but one hz down to 46hz from previous 47hz.
Put 4000w and did 152db at 47hz. Didn't have time to tune port and we found out our rear battery wasn't getting a charge so we'll have to come back and retest with full battery and change up some wiring.
And at lower frequencies we gained almost 1db over their best score.
Over all good gain but it's not perfect and there is still more to gain since when we open the trunk and burp it still loose .5db or more. That shows that the box is still using the trunk to load some.
But the really bad thing is when you close the back seat and seal the subs up again we now lose 8db so seats need to be down to be loud.
Car: 2 door Olds Alero Subs: Two DD9912's Amp: Stetsom 4k2d and PPI 4 channel Interiors: Focal front and rear Electrical: 190a alt, Stinger 1700 front, CS9000 back single run of 1/0 front to back with chaise ground.
Ok, so probably not minimum equipment to some but we went with stuff that we could beat the hell out of and won't blow during testing.
As some of you may or may not know I'm an Street Class SPL guy and fairly good at getting car's loud for spl. I do daily driver builds but not to often and what I have done are very strong for what they are. So my friend Mike Skaritka and myself got the bug to dabble in bass race this year. Mike has always had a killer system in his car for years and it's been a points getter doing 142db with a prefab box but he really wanted to make a monster trunk car with 2 12's and do some bass race.
To have a base line spl number to compare our first box to we tested his daily prefab slot ported box with his two hifonics brutus square 12's with the 4k2d. With 2800w clamped power 145.7db @ 43hz spl and 144db music. Not bad for a prefab box.
First attempt box was 5.3cf before displacement. Once port was tuned spl 149db @ 42hz with 2800w clamped power. And music consistent 148db. Not bad for first try but only problem box sounded little sloppy in the higher bass frequency range.
Second attempt we shrank the box down to 4.5cf before displacement but we didn't have the 4k2d to compare to. So we were stuck with an old PPI and with 300w clamped power on one channel spl 142.5 @ 45hz and music 141db. Then bridged amp and with 1100w clamped power and spl 146.6 @ 45hz and music 145.5db. Over 140 music with 300w power and a 4db gain with only 800w WOW.
So we gained ton of efficiency but didn't know if we got louder or not and couldn't really tune port either due to low power. So had to wait a couple weeks till we got time to put the 4k2d back in. (someone borrowed it)
Finally got the 4k2d in and with limited time we hat 149.8db @ 46-47hz and music 148.5-149 but didn't find have time to find right song for higher frequency. Now here's the kicker. I assumed we where getting about the same power as before with bigger box but since I knew the tuning was a little off and with smaller box impedance rise should be higher, I was wondered how much power we where doing the spl with. To my surprise only clamped 1900w from amp due to nasty impedance rise to 10ohm from 2ohms. And still haven't tuned port cuz we ran out of time.
So to clearify we gained .8db over old box with 900w less power. And efficiency went sky high to. I am hoping that once we tune the port it'll gain a couple more tenths if not more. And box sounds way better and plays much flatter. Within 1db from 40hz to 49hz.
So we're almost there to music consistent 149.9. We could shrink the box down to 4cf too and probably gain but this is a daily driver and don't really want to sacrifice the sq to much. But if we have to we'll do it.
Figured I'd share our testing of our first attempt at bass race and maybe give some other people some ideas for their trunk cars.
posted
That's awesome Jeff!!! But how many times in a row can you guys do a 149.9? That's where your going to run into issues, cause most of the 149.9 cars, trucks, or suvs have the head room and electrical to do it many times in a row. I know when I'm done with my ZX3 it'll do 149.9's all day, but I probably won't compete in that class that much. Anyway looks awesome and good luck with it. You will be the first person to do a 149.9 out of a trunk with 2 12's
-------------------- TEAM SUNDOWN AUDIO 2009 NSPL Car 1801-3600 Watt Record Holder: 151.2db 2009 NSPL Car 3601-Up Watt Record Holder: 152.6db 2009 NSPL Car Hardcore Record Holder: 155.2db 2009 NSPL Car 3601-UP, Car Hardcore, and Car Points World Champion Posts: 1848 | From: The Triad | Registered: Jan 2008
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posted
Yah, we're not that serious about being competitive in bass race just want to have fun in the 149.9 class with minimal equip. Since the amp is unregulated and limited battery we have I'd say only could do it a couple times. But haven't gotten there yet don't know.
Posts: 1770 | From: elgin | Registered: Jan 2003
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quote:Originally posted by TEAM SCHWARTZ: Looking good Jeff, in my experience you need to be able to burp in the 151 range to consistently do a 149.9.
If you up the battery power, I could see being able to do consistent 149.9's
Battery really isn't our limitation now since we're only dropping to 11.9v at lowest with music. Obviously if we up the power then we'll have a problem. But hopefully once port is tuned it'll gain a little more spl with more power. And there are things we can do to the box to get a little louder to. But we're close. thanks
Posts: 1770 | From: elgin | Registered: Jan 2003
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posted
I had a 2001 alero with 2 l715 in it. it did a 147.7db. that was back in a few years ago. mine liked to peak at 49 hz sub forward and port forward sealed off at the back seat. Just some info that worked for me
-------------------- TEAM PRODIGY
TEAM CROSSFIRE
TEAM KINETIK
2009 Bass Race World Champion 140.0db - 149.9db Class 2009 SBN Bass Race 140.0db - 149.9db 3rd place 2009 SBN IASCA NAC Bass Boxing 3rd Place Light Weight class 2008 SBN Bass Race 130.0db -139.9db Champion 2007 Indy Bass Race Champion 130.0db - 139.9db Class 2007 SBN IASCA Bass Boxing Fly Weight Class Champion 2007 SBN Bass Race Champion 130.0db - 139.9db class 2003 Sreet A World Finals very last place
CROSSFIRE, KINETIK Posts: 1214 | From: Canonsburg, Pa | Registered: Dec 2002
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quote:Originally posted by Team Prodigy Mike: I had a 2001 alero with 2 l715 in it. it did a 147.7db. that was back in a few years ago. mine liked to peak at 49 hz sub forward and port forward sealed off at the back seat. Just some info that worked for me
Actually having the box further inside the trunk is substantially louder then having it pushed forward to the opening of the trunk. Box uses the trunk like a bandpass box. If we push up the box 3" it looses .5db. And all the way to the front it looses over 1db. So further inside the trunk the louder for sure. But thanks for the suggestion.
Posts: 1770 | From: elgin | Registered: Jan 2003
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quote:Originally posted by Team Prodigy Mike: I had a 2001 alero with 2 l715 in it. it did a 147.7db. that was back in a few years ago. mine liked to peak at 49 hz sub forward and port forward sealed off at the back seat. Just some info that worked for me
Actually having the box further inside the trunk is substantially louder then having it pushed forward to the opening of the trunk. Box uses the trunk like a bandpass box. If we push up the box 3" it looses .5db. And all the way to the front it looses over 1db. So further inside the trunk the louder for sure. But thanks for the suggestion.
I experienced similar results with the box farther in the trunk. Preliminary testing I lost over 1.5 with it pushed forward.
I did however decide to move it forward and seal it completely and gave it a shot and found that I didn't lose anything.
Great job! Hope to be able to join you in the 49.9 class.
-------------------- TeamDefJ TeamNorthEast 150.0 Street C Posts: 243 | From: Auburn, NY | Registered: Jan 2009
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quote:Originally posted by TEAM SCHWARTZ: Looking good Jeff, in my experience you need to be able to burp in the 151 range to consistently do a 149.9.
If you up the battery power, I could see being able to do consistent 149.9's
Battery really isn't our limitation now since we're only dropping to 11.9v at lowest with music. Obviously if we up the power then we'll have a problem. But hopefully once port is tuned it'll gain a little more spl with more power. And there are things we can do to the box to get a little louder to. But we're close. thanks
I read in your post that you guys weren't serious about being competitive, but I have say your results are impressive using a trunk car.
I hope you decide to get serious and add some power and a little battery to back it up. I love loud trunk vehicles and it would be great to see one in the 49.9 class.
-------------------- "TECMO BOWL CHAMPION" Posts: 1354 | From: The Recession | Registered: Dec 2007
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quote:Originally posted by MrCrowley: have you tried port on driver side??
Having the port center is louder for sure. I think it's something to do with the the way the subs where loading.
Posts: 1770 | From: elgin | Registered: Jan 2003
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quote:Originally posted by TEAM SCHWARTZ: Looking good Jeff, in my experience you need to be able to burp in the 151 range to consistently do a 149.9.
If you up the battery power, I could see being able to do consistent 149.9's
Battery really isn't our limitation now since we're only dropping to 11.9v at lowest with music. Obviously if we up the power then we'll have a problem. But hopefully once port is tuned it'll gain a little more spl with more power. And there are things we can do to the box to get a little louder to. But we're close. thanks
I read in your post that you guys weren't serious about being competitive, but I have say your results are impressive using a trunk car.
I hope you decide to get serious and add some power and a little battery to back it up. I love loud trunk vehicles and it would be great to see one in the 49.9 class.
As of now Mike just wants to show up at shows with a hell of a trunk car to have fun. If he get's the bug he'll consider taking it more serious. We'll see.
Posts: 1770 | From: elgin | Registered: Jan 2003
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posted
i'm trying to get my buick up to 49.9 with 1 15 right now, but probly 2 12s when i'm done, but it'll just be bassrace so i'm getting extra batteries in there
Posts: 322 | From: Brantford, Ontario | Registered: Oct 2007
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quote:Originally posted by Rossfreier: i'm trying to get my buick up to 49.9 with 1 15 right now, but probly 2 12s when i'm done, but it'll just be bassrace so i'm getting extra batteries in there
Single 15 will be a little harder to do if you're wanting to music a consistent 149 but doable. You'll need one hell of a strong sub that can take a lot of power. And a good box will be key to getting there. Good luck.
Posts: 1770 | From: elgin | Registered: Jan 2003
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posted
good to see a trunk build im using a estate in the uk its a street c car and im doing 149.9 bassrace im using 1 NSB 75 in the front a NSB 90 in the boot and 2 atomic 5k amps strapped to 0.5 ohm and 4 atomic 12 ele dual 2s the main thing i find is youve got to be really good on the start as you havent got as much headroom
Posts: 6 | From: England | Registered: Aug 2008
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quote:Originally posted by vaux_boy: good to see a trunk build im using a estate in the uk its a street c car and im doing 149.9 bassrace im using 1 NSB 75 in the front a NSB 90 in the boot and 2 atomic 5k amps strapped to 0.5 ohm and 4 atomic 12 ele dual 2s the main thing i find is youve got to be really good on the start as you havent got as much headroom
For sure. We could build a louder box for more headway for sure but we'd sacrifice a lot of sq and since it's not just a bass race vehicle that's not our goal. If we could get another 1db from box I think we'll be good.
Posts: 1770 | From: elgin | Registered: Jan 2003
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posted
vaux_boy was street c champion in the UK last year, he also does a mean bass race, but before you guys try to knock him, he is at over 152db at 41hz so far from a one note wonder it plays music very nicely
-------------------- Posts: 432 | From: derbyshire, england | Registered: Dec 2002
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quote:Originally posted by dumdum: vaux_boy was street c champion in the UK last year, he also does a mean bass race, but before you guys try to knock him, he is at over 152db at 41hz so far from a one note wonder it plays music very nicely
I don't think that anyone was trying to knock him at all. That's impressive for a trunk score none the less.
-------------------- TEAM SUNDOWN AUDIO 2009 NSPL Car 1801-3600 Watt Record Holder: 151.2db 2009 NSPL Car 3601-Up Watt Record Holder: 152.6db 2009 NSPL Car Hardcore Record Holder: 155.2db 2009 NSPL Car 3601-UP, Car Hardcore, and Car Points World Champion Posts: 1848 | From: The Triad | Registered: Jan 2008
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