How do you find out what the resonance of your car is?

JstasJstas Posts: 13,724
edited June 2008 in Car Subwoofer Talk
This goes along with the other thread.

Since I have not done this before, I'm trying to find out how to do it so I know if it's being done right.

Anybody know?
You're just jealous 'cause the voices don't talk to you!
Post edited by Jstas on

Comments

  • disneyjoe7disneyjoe7 Posts: 11,520
    edited April 2008
    I'm thinking a speaker mounted in car, amp to power it, frequency generator to feed it a fixed Hz, a microphone, a o-scope to find peak in frequency heard? Just some ideas off my head, good luck. :)

    Speakers
    Carver Amazing Fronts
    CS400i Center
    RT800i's Rears
    Sub Paradigm Servo 15

    Electronics
    Conrad Johnson PV-5 pre-amp
    Parasound Halo A23
    Pioneer 84TXSi AVR
    Pioneer 79Avi DVD
    Sony CX400 CD changer
    Panasonic 42-PX60U Plasma
    WMC Win7 32bit HD DVR


  • BradimusMaximusBradimusMaximus Posts: 60
    edited April 2008
    As I understand it you do exactly what Joe said but with one stipulation. You have to do it outside the car with the same enclosure and amp with the same settings. You need something to compare that peak against so if you run some nice long speaker wires from the amp you can set the box on some sort of platform out in the open and run the same tests. That is how I read to do it anyway.
    Pioneer Premier DEH-P980BT
    Alpine SPX-137R
    Alpine SPR-69LP
    Panasonic CY-PA4003U
    Kenwood KAC-X520
    Polk SR124 :D
  • JstasJstas Posts: 13,724
    edited April 2008
    Where did you read this?
    You're just jealous 'cause the voices don't talk to you!
  • MacLeodMacLeod Posts: 14,365
    edited April 2008
    Try Elite Car Audio. Thats the premier car audio forum with experts-a-plenty. I guarantee ya somebody over there can give you way more information than you ever wanted!

    http://forum.elitecaraudio.com/index.php
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D
  • BradimusMaximusBradimusMaximus Posts: 60
    edited April 2008
    I'll try and find that again and post it up for you.

    http://www.caraudiomag.com/technical/0203cae_audio_speakers_basics/index.html

    This link I posted earlier gives you a different method that uses some measurements and math to figure out the same thing.
    Pioneer Premier DEH-P980BT
    Alpine SPX-137R
    Alpine SPR-69LP
    Panasonic CY-PA4003U
    Kenwood KAC-X520
    Polk SR124 :D
  • exalted512exalted512 Posts: 10,796
    edited April 2008
    Well, like you said in your previous post, EVERYTHING effects this. Ideally, youd want your box in and loaded, any deadening your going to do be done, then test.

    The cheap and easy way to do it is with a 10" sealed sub with as flat frequency response as you can get. Then get a CD with some test tones from say, 45-100, a spl meter (or rta) and let it play through. The frequency with the highest reading is your frequency.

    Now thats not 100% accurate, but pretty damn close (usually has a standard error of about 6 Hz as I've been told). Either way, if your frequency is 62, tune at about 59 and go from there. Removable ports are a must.

    Are you wanting to get back into the SPL lanes or just curious about the info? I can help you out more but I'd rather do it through PMs.
    -Cody
    Music is like candy, you have to get rid of the rappers to enjoy it
  • JstasJstas Posts: 13,724
    edited April 2008
    Well, the guys I was talking about in the previous post compete and they are at a loss as to how to get the car louder. They asked me for help and like I said, I related my thoughts and experiences on making cars go "boom" and they balked. So I wanted to find out more about how they did it and after learning more in the other post and reading all over the web, I think they tested wrong and are off on their resonant frequency. I know they are off on the box design because even Memphis Audio says the box should be about 4.5 cubic feet at the largest and not the 6 cubic foot beast he has now.

    Building the box is easy. Getting the appropriate info to build the box properly is difficult. But they want me to "put my money where my mouth is" so to speak so my one friend and I are gonna put together a box for his subs and see what we can do. Even if I pick up 2 dB over the current setup, it's a success because he will be about 1.5 dB ahead of his next closest, local competitor. So yeah, I guess I am getting back in to the SPL lanes. I'd prefer the SQ lanes 'cause I know I can clean up there but there might be some employment in this for me too. So PM away if you want.
    You're just jealous 'cause the voices don't talk to you!
  • BradimusMaximusBradimusMaximus Posts: 60
    edited April 2008
    Let us know what kind of numbers you get!
    Pioneer Premier DEH-P980BT
    Alpine SPX-137R
    Alpine SPR-69LP
    Panasonic CY-PA4003U
    Kenwood KAC-X520
    Polk SR124 :D
  • exalted512exalted512 Posts: 10,796
    edited April 2008
    What subs and amps does he have and what kind of vehicle? As well as, what are your buddies competing in and with? Also, do you know what numbers theyre hitting and on what meter?
    -Cody
    Music is like candy, you have to get rid of the rappers to enjoy it
  • disneyjoe7disneyjoe7 Posts: 11,520
    edited April 2008
    Does anyone wish to start a poll of what the resonance of a car would be?

    My guess 43Hz to nearest one to a whole number wins, wins what?


    Steve

    Speakers
    Carver Amazing Fronts
    CS400i Center
    RT800i's Rears
    Sub Paradigm Servo 15

    Electronics
    Conrad Johnson PV-5 pre-amp
    Parasound Halo A23
    Pioneer 84TXSi AVR
    Pioneer 79Avi DVD
    Sony CX400 CD changer
    Panasonic 42-PX60U Plasma
    WMC Win7 32bit HD DVR


  • JstasJstas Posts: 13,724
    edited April 2008
    exalted512 wrote: »
    What subs and amps does he have and what kind of vehicle? As well as, what are your buddies competing in and with? Also, do you know what numbers theyre hitting and on what meter?
    -Cody

    He has Memphis M3124D's, a pair of them. I forget what amp, I think it's also a Memphis. I don't know what class they are competing in but they will hit any show that shows up. IASCA...honestly, you name it. As far as microphones, don't know, gotta find that one out.

    The car is a Jetta Sedan, early 2000's I think. They are in the 142-147 range depending on the microphone and test gear. He has another guy with a Honduh Cibbic hatch hitting a good 8-10 dB above him across the board. The box is smaller but the space inside the cabin is much bigger because of all the space in the rear greenhouse that comprises the hatch area. I'll get the rest of the info for you next week. They away visiting family this weekend.
    You're just jealous 'cause the voices don't talk to you!
  • JstasJstas Posts: 13,724
    edited April 2008
    disneyjoe7 wrote: »
    Does anyone wish to start a poll of what the resonance of a car would be?

    My guess 43Hz to nearest one to a whole number wins, wins what?


    Steve

    Every car has a different resonance. You can take two, we'll say, 1999 Lincoln LS sedans. They can be "identical" Equal trim levels, equal options, equal drive trains and everything and test resonance on both of them and the will have different resonances.
    You're just jealous 'cause the voices don't talk to you!
  • exalted512exalted512 Posts: 10,796
    edited April 2008
    As well as have different resonances in different areas of the car.
    -Cody
    Music is like candy, you have to get rid of the rappers to enjoy it
  • disneyjoe7disneyjoe7 Posts: 11,520
    edited April 2008
    Jstas wrote: »
    Every car has a different resonance. You can take two, we'll say, 1999 Lincoln LS sedans. They can be "identical" Equal trim levels, equal options, equal drive trains and everything and test resonance on both of them and the will have different resonances.



    Really :confused: I would never think so on paper so to speak.

    Speakers
    Carver Amazing Fronts
    CS400i Center
    RT800i's Rears
    Sub Paradigm Servo 15

    Electronics
    Conrad Johnson PV-5 pre-amp
    Parasound Halo A23
    Pioneer 84TXSi AVR
    Pioneer 79Avi DVD
    Sony CX400 CD changer
    Panasonic 42-PX60U Plasma
    WMC Win7 32bit HD DVR


  • BradimusMaximusBradimusMaximus Posts: 60
    edited June 2008
    So did you ever build a box Jstas?
    Pioneer Premier DEH-P980BT
    Alpine SPX-137R
    Alpine SPR-69LP
    Panasonic CY-PA4003U
    Kenwood KAC-X520
    Polk SR124 :D
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