Which is Louder: Sedan or Station Wagon??

9 years 1 month ago - 9 years 1 month ago #1 by Andy
OK, well a few people have given me an idea to test which car would be louder using the same gear, volume etc.
It just so happens i had a sedan and station wagon, both of the same model! I also happened to have the Termlab testing equipment with me and a spare day, so why not?

The sedan is a VS Executive
The Wagon is a VR Berlina

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The Equipment:

Subwoofer: eBay "American Boss" 12" DVC 4 ohm Subwoofer, rated at 500wrms on a really, really good day.
Enclosure: 1.1 cu.ft. Sealed, 16mm MDF.
Amplifier: Cutting Edge CE2200P, 2 x 200wrms / 1 x 600wrms at 4 ohm. Will be wired to 2 ohms bridged.
Battery: Optima D31 yellow Top with variable PSU attached - set to 13.8v
Source: Test tones on iPhone using 3.5mm to RCA cable.
SPL Meter: Termlab - sensor on P/S of windscreen (DB Drag) or close enough.

The amp, battery, iPhone and Laptop were all, to make it easier to swap in between cars.

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Testing Procedure:

* Put sub box in centre of luggage area facing rearwards, run a sweep at full volume and find peak frequency.
* Wait a few minutes for sub to cool and play that frequency at full volume.
* Repeat trying different box configurations etc.



Results:

First up i tested the wagon, found it peaked at 49hz:


1st run, box in centre of luggage area facing back: 130.5db
2nd run, box in centre of luggage area facing up: 127.5db
3rd run, box in centre of luggage area facing forward: 130.2db
4th run, box in the centre of luggage area but placed right at the back (5cm from tailgate) to add more loading on the sub: 131.1db

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So thats about as much as i could get out of the wagon with that gear.


OK so the sedan, same procedure as the wagon:

1st run, box in centre of boot facing back: 129.7db
2nd run, box in centre of boot facing back: 129.2db
3rd run, box in drivers side corner of boot facing diagonally towards tailight: 130.0db
4th run, box in centre of boot about 10cm away from boot latch to add more loading on the sub
AND put the ski port down: 134.3db:

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I was pretty shocked with the score so needless to say i did two backup runs without touching anything but the "pause" and "play" buttons on my iPhone. The score was repeated twice and i even put the box back into the wagon and recorded a 131.1db.

EDIT: To all those that know what a Termlab readout shows, yes i know the 131.1db score shows a crapload of clipping, whilst the 134.3db dosent, dont ask me why......both scores were set using the same gear, setting etc. just different cars.
9 years 1 month ago #2 by Tezzating
What Termlab read out ? :P

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9 years 1 month ago #3 by Andy
Yes OK OK i got lazy and didnt do the image tags.....happy now? :lol:
9 years 1 month ago #4 by Tezzating

C.C.S.S. wrote: Yes OK OK i got lazy and didnt do the image tags.....happy now? :lol:


A bit :P

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9 years 1 month ago #5 by Andy
Well.....do we get ANY type of comment from the testing / tutorial king?
:laugh:
9 years 1 month ago #6 by Dylan
I see your copping a bit of shit about this on MEA. They are to damn anal retentive over there. Can't just take the test for what it's worth.

How are they responding to it on the commodore forums?
9 years 1 month ago #7 by zion187reigneth
good tute,This must be on the minds of 50,000 newb SPL'ers.
9 years 1 month ago #8 by Tezzating

C.C.S.S. wrote: Well.....do we get ANY type of comment from the testing / tutorial king?
:laugh:


Sorry :P Did I mention I bought a new XBOX and Fable 3 ? If not.. I did and Fable is a demanding mistress..

Firstly let me say the testing method is sound. Using a sealed enclosure of the appropriate volume to give a flat response curve is a smart move, this removes SPL peaks due to Fs or port tuning resonances. Everything else is done right.. cool down and recharge times, etc. I trust that Andrew's got the experience and knowledge to run these tests correctly, and they were done on a TL so the numbers are accurate.

The only two things I'd comment on is you dont mention the the peaking frequency for the sedan, and I'd like to see a "sub of passengers side, facing the drivers side shock tower" result as well. But mostly for my own curiosity.

I find it interesting that the Wagon Forward & Wagon Back results are so close ! My testing usually found a huge drop firing forward, but only a few 0.1's is amazing.
The sedan results are so close to each other I would suspect because the wave doesnt get a chance to fully propogate with the ski-hatch closed, its just resonating out of the panels.. slightly higher in a diagonal firing cos it increases the panel resonance, but the gains so minimal you'd never know it by ear :P

Ski hatch open increasing SPL makes sense. Gives the wave a chance to fully propogate, and you gain an order of resonance. The boot area acts like a larger enclosure blah blah. Boyles Law and all that stuff.. decibelcar.com/index...

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9 years 1 month ago #9 by Tezzating

Dylan wrote: I see your copping a bit of shit about this on MEA. They are to damn anal retentive over there. Can't just take the test for what it's worth.


Its why I dont go there anymore.. also, there's a phenomena on web forums where false information becomes regarded as fact, simply because someone says it with conviction, and the readers take it as truth. That place is a great example of it.

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9 years 1 month ago - 9 years 1 month ago #10 by Andy
Not really copping shit on MEA IMO, just the usual crap that happens over there....TBH the only forums i care about the responses is here and from selected people on the Commodore forums, which is fairly good atm.

Both cars peaked at 49hz, the sedan actually peaked at 48hz with a sweep. But with tones it moved up 1hz, the wagon peaked at 49hz with the sweep and tones.

I think the reason why the wagon scores for front and rear firing were so close because i tested the wagon with the rear bench seat up, so the sub was actually loading on something. It did 130.9db with the box 5cm from the tailgate and the rear seat up. I ut the rear seat down and it did the 131.1s. I could have gotten more out of adjusting the seats and sunvisors, but didnt want to do that and more than likely both cars would show the same gains.
Thanks for the input Steve. It took a whole of 5 hours from getting the idea to completing the testing and posting the results. Not what i would call well planned, but i think this has brought up a few interesting points so im keen to step it up a notch....might even organize something for the Singleton SPL comp ;)
9 years 1 month ago #11 by zion187reigneth

C.C.S.S. wrote: so im keen to step it up a notch....might even organize something for the Singleton SPL comp ;)

Dont forget the dbcar.com Banner
9 years 1 month ago #12 by Tezzating

zion187reigneth wrote: Dont forget the dbcar.com Banner


I like the way you think ;)


I thought you did the wagon seats down from the start :P the numbers make a bit more sense with the seats down ;).
If you do something cool at the Singo show, get some video 'cos I'd love to edit it up and slap it onto the DBC YouTube channel.

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9 years 1 month ago #13 by Dylan
I wish I didn't cop a fine. Singo show would have been awesome with the forester all DBC.com stickered up doing 147-148dB and demoing music.

Fucking cops :(
9 years 1 month ago #14 by Andy
Yeah Steve it made crap all difference to me car so i didnt even think about it until right at the end.....It was only 0.2db difference so dont stress :P
Its all good Dylan, you will be missing a great show (best the Hunter Valley has IMO)....but theres always next time. Im going to have some problems with the comp being my first one, so i'd rather you be apart of a properly run comp thats more about having a good time and less about who beat who.
This Termlab has dual sensors and ive figured out a way to display the scores on another screen for the competitors to see....so that part should work out OK.

DBC banner......does one exist? If not i'll look into it ;)
9 years 1 month ago #15 by Tezzating
No a DBC banner doesnt exist.. yet, aparantly ? :P

Good Luck with Singleton show BTW.. sounds like a good weekend.

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9 years 1 month ago #16 by Dylan
Man, the ONLY shows I have been to that are not about who beat who is Tony's comps. I'm used to all the BS.

Remember that show you came to in Port Mac? There was so much BS that went on after that show it's not funny.

I'd rather show up to your first comp and try and lend a hand.
9 years 1 month ago #17 by Andy
Sorry been working too much and now have a chest infection.......not fun in 32 degree heat :sick:


Where is this banner i keep hearing about? :P
9 years 4 weeks ago #18 by Tezzating

C.C.S.S. wrote: Sorry been working too much and now have a chest infection.......not fun in 32 degree heat :sick:


Where is this banner i keep hearing about? :P

haha, doesnt exist, but I think Dylan wants to make one :P

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9 years 4 weeks ago #19 by Dylan
I should probably look into it hey.

Andrew, what is the address of the venue that is holding the show?
9 years 4 weeks ago - 9 years 4 weeks ago #20 by Andy
Oh Dylan, you have the banner.....dont worry about the show's address to send it to, just post it to my address with the stickers :laugh: :laugh:

Seriously though, its at the Singleton Showground which is on York St.


Im not having much luck with borrowing more gear for testing at the moment, so it may have to be after the comp that it gets done....probably with Autobarn sponsoring it ;)
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