# a cars peak?



## LOUD MAV (Dec 17, 2013)

im real into spl. I like sq. and all but I love the bass. ive started from scratch abd gettin and alk new set up with this car. a 1972 ford maverick. I wanna get the most out of my bass.and always read.things about a cars peak,a boxes peak, etc. 

my first question is.how to find a cars.peak? I see this one alot abd was wondering how to figure that out


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## schmiddr2 (Aug 10, 2009)

http://www.diymobileaudio.com/forum...120190-does-anyone-understand-cabin-gain.html


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## ccapil (Jun 1, 2013)

Ways to determine resonant frequency: ''There are few different ways to determine the resonant frequency of your vehicle, all of which requires the use of SPL or RTA meters. The most common and what i believe is the easiest is by using a Term Lab meter. Aside from the meter, you'll also need a test CD with a frequency sweep as well as individual frequency tracks. For this we used the IASCA Max dB CD as it has all the tracks needed.You'll also need a 10'' subwoofer in a 1.0 cubic foot sealed enclosure, and no, this is not negotiable. You can't use a vented enclosure to determine the car's resonant frequency as the results will be skewed. All you'll possibly determine by using a ported enclosure is what the enclosures peak frequency is and nothing more. The final bit you'll need is a pen and paper to log everything.''

How to do it: ''Turn any sort of bass boost, equalization or processor settings down so you get a flat response from the amplifier,head unit and any form of processing. You'll then need to remove any existing subwoofer/s and enclosure and replace it with the 10'' woofer in it's sealed enclosure. This will need to be connected to your existing amplifier. Position the 10'' sub as close to the center of the vehicle as possible with the cone facing rearward. Next you'll need to start up your term lab meter and place the sensor on the windscreen as you typically would for an SPL reading. Set the Term Lab to ''Peak Hold'' as this will show you the highest score and the frequency graph at the bottom of the screen will indicate what the frequency is. Place the CD with the frequency sweep into the player, set it on a constant volume and do not adjust the volume while the sweep is being played. You'll need a friend to help you by pressing start on the Term Lab first which will be followed by you turning the volume up and then pressing play on the track. Don't bang the little 10'' subwoofer flat out. If it plays at about 130db, that's ideal. The frequency graph at the bottom will pinpoint the peak frequency and if you're still not sure how to read it, the display on the side of the SPL score will tell you what the peak SPL and frequency is. On the VW Polo Vivo, the resonant frequency we got was 52Hz . To confirm your test results, skip to 50Hz on your test CD and start playing each track from there all the way up to 55Hz. Each test needs to be at the same volume with no changes. You should ideally land up achieving your highest score(SPL reading) at 52Hz which confirms the previous test. If you don't get the same result, start the entire test again as you've done something wrong.

Once you know the resonant frequency of your cabin, you can proceed to measure the boot and start designing your ideal SPL enclosure.''


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## peenemunde (Aug 31, 2013)

ccapil said:


> Ways to determine resonant frequency: ''There are few different ways to determine the resonant frequency of your vehicle, all of which requires the use of SPL or RTA meters. The most common and what i believe is the easiest is by using a Term Lab meter. Aside from the meter, you'll also need a test CD with a frequency sweep as well as individual frequency tracks. For this we used the IASCA Max dB CD as it has all the tracks needed.You'll also need a 10'' subwoofer in a 1.0 cubic foot sealed enclosure, and no, this is not negotiable. You can't use a vented enclosure to determine the car's resonant frequency as the results will be skewed. All you'll possibly determine by using a ported enclosure is what the enclosures peak frequency is and nothing more. The final bit you'll need is a pen and paper to log everything.''
> 
> How to do it: ''Turn any sort of bass boost, equalization or processor settings down so you get a flat response from the amplifier,head unit and any form of processing. You'll then need to remove any existing subwoofer/s and enclosure and replace it with the 10'' woofer in it's sealed enclosure. This will need to be connected to your existing amplifier. Position the 10'' sub as close to the center of the vehicle as possible with the cone facing rearward. Next you'll need to start up your term lab meter and place the sensor on the windscreen as you typically would for an SPL reading. Set the Term Lab to ''Peak Hold'' as this will show you the highest score and the frequency graph at the bottom of the screen will indicate what the frequency is. Place the CD with the frequency sweep into the player, set it on a constant volume and do not adjust the volume while the sweep is being played. You'll need a friend to help you by pressing start on the Term Lab first which will be followed by you turning the volume up and then pressing play on the track. Don't bang the little 10'' subwoofer flat out. If it plays at about 130db, that's ideal. The frequency graph at the bottom will pinpoint the peak frequency and if you're still not sure how to read it, the display on the side of the SPL score will tell you what the peak SPL and frequency is. On the VW Polo Vivo, the resonant frequency we got was 52Hz . To confirm your test results, skip to 50Hz on your test CD and start playing each track from there all the way up to 55Hz. Each test needs to be at the same volume with no changes. You should ideally land up achieving your highest score(SPL reading) at 52Hz which confirms the previous test. If you don't get the same result, start the entire test again as you've done something wrong.
> 
> Once you know the resonant frequency of your cabin, you can proceed to measure the boot and start designing your ideal SPL enclosure.''


This is wonderful, thank you


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## PsyCLown (May 17, 2013)

ccapil said:


> Ways to determine resonant frequency: ''There are few different ways to determine the resonant frequency of your vehicle, all of which requires the use of SPL or RTA meters. The most common and what i believe is the easiest is by using a Term Lab meter. Aside from the meter, you'll also need a test CD with a frequency sweep as well as individual frequency tracks. For this we used the IASCA Max dB CD as it has all the tracks needed.You'll also need a 10'' subwoofer in a 1.0 cubic foot sealed enclosure, and no, this is not negotiable. You can't use a vented enclosure to determine the car's resonant frequency as the results will be skewed. All you'll possibly determine by using a ported enclosure is what the enclosures peak frequency is and nothing more. The final bit you'll need is a pen and paper to log everything.''
> 
> How to do it: ''Turn any sort of bass boost, equalization or processor settings down so you get a flat response from the amplifier,head unit and any form of processing. You'll then need to remove any existing subwoofer/s and enclosure and replace it with the 10'' woofer in it's sealed enclosure. This will need to be connected to your existing amplifier. Position the 10'' sub as close to the center of the vehicle as possible with the cone facing rearward. Next you'll need to start up your term lab meter and place the sensor on the windscreen as you typically would for an SPL reading. Set the Term Lab to ''Peak Hold'' as this will show you the highest score and the frequency graph at the bottom of the screen will indicate what the frequency is. Place the CD with the frequency sweep into the player, set it on a constant volume and do not adjust the volume while the sweep is being played. You'll need a friend to help you by pressing start on the Term Lab first which will be followed by you turning the volume up and then pressing play on the track. Don't bang the little 10'' subwoofer flat out. If it plays at about 130db, that's ideal. The frequency graph at the bottom will pinpoint the peak frequency and if you're still not sure how to read it, the display on the side of the SPL score will tell you what the peak SPL and frequency is. On the VW Polo Vivo, the resonant frequency we got was 52Hz . To confirm your test results, skip to 50Hz on your test CD and start playing each track from there all the way up to 55Hz. Each test needs to be at the same volume with no changes. You should ideally land up achieving your highest score(SPL reading) at 52Hz which confirms the previous test. If you don't get the same result, start the entire test again as you've done something wrong.
> 
> Once you know the resonant frequency of your cabin, you can proceed to measure the boot and start designing your ideal SPL enclosure.''


Very nice!

Although I am curious, any idea why it has to specifically be a 10" driver?
The sealed vs ported difference I can understand.


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## LOUD MAV (Dec 17, 2013)

yes I was curious as well bout why a 10"


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## HiloDB1 (Feb 25, 2011)

It could be almost any size driver as long as the enclosure was sized to create a relatively ideal q to get a flat response from the driver and it was able to play low enough. There are lots of factors that go into SPL systems. Do you just want it to sound loud or do you want it to meter big numbers? Two totally different paths need to be taken depending on what your final goals are.


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## LOUD MAV (Dec 17, 2013)

just loudness lol...ill never get it metered..jus want it LOUD for my sakes, I need bass to keep up with an 8" prv two 6" prv and a prv super tweet in each door to keep up with


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