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has anyone ever set down and calculated the resonant frequency of a civic? I dont think i have the process right, cause I came to teh conclusion that its 44 Hz, and while fitting teh equasion i think i remember from so long ago, it really doesnt match up to what my data says (I think)

so anyone here know how to measure res freq, or done it? or an i right, and its 44 Hz?

 
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You have way to much time on your hands[IMG]i/expressions/face-icon-small-tongue.gif[/IMG]

 
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lol that's pretty much what I was thinking but too restrained to say.

 
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<< You have way to much time on your hands[IMG]i/expressions/face-icon-small-tongue.gif[/IMG] >>




well, ever since my ex left me for another guy, i seem to have more time than ever before! ......

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...

;_;

 
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[IMG]i/expressions/face-icon-small-smile.gif[/IMG]Just a thought, but instead of worrying about the resonant frequency go find another woman....Just dont find one that dosen't date a man that dosent know the resonant frequency of their car.... [IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG]

 
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In the sedans there's 2 res frequencies.. 38hz, and 71hz......if your coupe's is 44hz, then you should be hitting your best SPL numbers using a 47-49hz tone with your port tuned to 40hz.

CHeers
Mohawk

 
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actually, since you know mowhawk, maybe you could confirm the process for finding the res freq. and dont tell me there are two in my civic, cause I know that its more than just a product of teh two peaks that i get in the car---- the box has a response too!

as far as what to do with it....i disagree with you there completely, but i wont bother - no point.

so how did YOU figure out res freq? plz tell me you didnt jsut take teh spl curve of your boxes performance, its not that simple! (mine turned out similar, BTW)

 
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It's really easy to do with alot of time and a Cheap radioshack mic..and liberal neighbors lol..

Ramove the sub from your car.. Set your HU to a moderate listening level (not too loud but good).. Have the sub in your back yard about 10 feet away from any solid objects..with the sub facing an open field or something. Play test tones. Graph each SPL rading on some graph paper for each frequency..(this will give you your enclosures fequency response... Then put the sub back in the car.. do not touch the volume setting on your HU..Play through Each test tone again from Inside the car.. you'll find your Cabin gain factor.. and your cars Resonant frequency(s)...

It's very common for cars to have 2 resonant frequencies.. however in most cases for one of them is above 80HZ and pointless for SPL competition..

Disagree with what you wish.. but base your disagreements of education...and not guessing what you think is right..

Cheers
Mohawk

 
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haha no matter how many people i talk to, this is the exact same answer i get.... its not that simple!

noone wants to say what you do with teh curves..... peopple only want to say how you take the measurements..... then i ask if it is a simple matter of subtraction..... no answer.........

ive even been told there is a formula involving distance to mic and a bunch of other variables! haha.

and i cant believe that volume level is a factor. cause mic position is a factor too, and where the mic is will change the SPL results.......

but from what little i can infer from this, and even less from everyone else, ill make due. i guess ill have to do the old test method of confirming my res freq =/.

im gonna look into this double freq. thing. cause it seems to me that the only way a car would have multiple freq woul dbe if they are harmonics of each other...... my physics is a bit rough, is 71 a harmonic of 38? cause that dont sound right..........

 
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ok, figued it out. a car CAN have two res freq, but its not really heard of in my circles. a perfect rectangualr prisim will have 3 res freq. one for each DIFFERENT side. a car has a much more complex shape of course, but that is the idea. as far as a CIVIC is concerned, the coupe is actually much closer to 55, i need to confirm by retaking my measurements (they were diff volume levels)

http://www.calpoly.edu/~sciccare/SPLChart.gif

you can use this data to find the transfer curve for civics, and use that to find the exact res freq. you can see the two peaks for the in car measurement. there are not two res freq, one at 33ish and the other at 55ish, but rather 44 Hz is a "bass sink hole" where the frequencies are getting canncelled on thier way to the front (a poor tuning choice for a ported box, good thing i didnt tune to that!) the "peak" at 33ish is actualy part of the bass transfer curve, which would look alot more like the out of car SPL cuve had there not been that 44 hz sink hole. THAT is what caused the two peaks. around 55ish is where the SPL gets boosted slighty above the transfer curve, and therefore its around there that the coupe's res frequency lies

i think i feel jealous, our coupe only has one "useful" res freq ;_; [IMG]i/expressions/laugh2.gif[/IMG]

so there ya go. 55ish for now, the "true" measured value is yet to come!

 
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Okay so your posting stuff that you allready found your answers to and wasting other peoples time to try to show off what you know huh?.. Did you know that the actual displacement of your subwoofer enclosure will affect this also..

Not to mention it will be different with you sitting in the car...

Mic Position is a big factor...as well.With proper knowledge of Physics and Psychoacoustics you can create curves in your car to focus 80% of your bass output into one small area of your car..

The example I gave you is not for your cars true resonant frequency, However it's how to determine your cars Transfer function..Weather will also affect your resonant frequency as materials become less flexible in the cold, or more maluable in the heat.....I haven't gotten into that just yet as I'm much more concerned on getting my car to sound the best it possible could...

Now you seem to like posting things for the sake of showing off your knowledge based on tidbits of what you find that you are taking as absolute fact....

Now..please enlighten us all with examples and links to where we can find all this info on how to properly find out cars true resonant frequency??.. Besides the fun old transfer function method..(which is about 95% accurate in finding your cars res frequency) ..

Cheers
Mohawk

 
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<< Okay so your posting stuff that you allready found your answers to and wasting other peoples time to try to show off what you know huh?.. Did you know that the actual displacement of your subwoofer enclosure will affect this also..
Cheers
Mohawk >>



*sigh* unprovoked this time =/

well take a look at my first post. i said i thought it was 44. I was looking for confirmation. I wanted to know if the process i went through to figure that out was correct. not only was it not correct, it was teh frequency of the suckhole of my civic! not a good thing to tune to!

as to links, I cant provide any, I was talking to a buddy from my audio forum in chat, he told me step by step how to calculate transfer function, and how that applies to the in car res feq.

i dont doubt that there are a billion factors and that its all horrible complex.....but as you said, if the easy way out is 95% effective, then its easy adjustment to fine tune for max SPL, but now we are talking about getting in those 10ths of a Db, i wanted to ball park it so i wasnt loosing several db.

im sorry if i am wasting space on your server. if you dont think i should be looking for the answers to my questions on this forum, feel free to ban me. obviously I did not start this thread knowing the answeres to my questions, cause i was WAY off at the time!

 
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<< Now..please enlighten us all with examples and links to where we can find all this info on how to properly find out cars true resonant frequency??.. Besides the fun old transfer function method..(which is about 95% accurate in finding your cars res frequency) ..

Cheers
Mohawk >>



from what you were saying earlier (lets also assume this is true) you cant ever find a car's TRUE res freq, cause all the factors you list are not constants. but again, i ask (assuming 95% accurate is a truw statement also) does it really matter about the other factors? can we not assume that that method is perfectly ok, then fine tune that day before you hit the lanes?

 
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<< [IMG]i/expressions/face-icon-small-smile.gif[/IMG]Just a thought, but instead of worrying about the resonant frequency go find another woman....Just dont find one that dosen't date a man that dosent know the resonant frequency of their car.... [IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG] >>



id like to, but im a loser who doesnt go out, so i never meet women hahahaha [IMG]i/expressions/face-icon-small-sad.gif[/IMG] =p


not me -------&gt;[IMG]i/expressions/face-icon-small-cool.gif[/IMG] hahaha

 
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<< Now you seem to like posting things for the sake of showing off your knowledge based on tidbits of what you find that you are taking as absolute fact....
Cheers
Mohawk >>



lol to quote again: "man you ahve really got to get that sand outta your vagina..." lol

im jus playin' dude. [IMG]i/expressions/face-icon-small-tongue.gif[/IMG] have a [IMG]i/expressions/beer_yum.gif[/IMG] on me

 
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this is halarious....you 2 dont stop.....

come on men, give it a rest......

RF Bwoy

 
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We argue and ish.. but we both always seem to come out knowing alot more than we started [IMG]i/expressions/face-icon-small-smile.gif[/IMG]....

Also note.. sub placement and subwoofer enclosure size can affect your res frequency/Transfer function..if more space is filled it makes the interior of the car smaller..

The statement is about 95% accurate is true, if you use the same subwoofer, in the same enclosure in the same placement.. otherwise it will still get you within +/- 2hz so it's easy to fine tune from there...

Also.. any suggestions on how to get the sand from my Vagina?..it's been bugging me alot.. I tried a Douche..Monistat..nothing works

Cheers
Mohawk