LYLE Posted January 14, 2013 Report Share Posted January 14, 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.'' Link to comment Share on other sites More sharing options...
alaskanzx5 Posted January 14, 2013 Report Share Posted January 14, 2013 after doing a sweep you should first let everything cool down andlet the batteries charge up a bit. it will allow you to get the best possible answer. however from what i have read this test is never 100% because of the fact that the position of seats, passengers, or the direction of the sub and the subs freq response can create differences. t1500bdcp 2 t2d4 15" 1 t600.4 1 t400.2 1 set p1 tweets singer alt, tons of wiring, smd vm-1, 80prs, back seat delete, still in the works, aiming for a 145-147 with the ability to play 25hz up to 50hz. Link to comment Share on other sites More sharing options...
Carbon Posted January 20, 2013 Report Share Posted January 20, 2013 after doing a sweep you should first let everything cool down andlet the batteries charge up a bit. it will allow you to get the best possible answer. however from what i have read this test is never 100% because of the fact that the position of seats, passengers, or the direction of the sub and the subs freq response can create differences. Good info! Link to comment Share on other sites More sharing options...
n8ball2013 Posted January 20, 2013 Report Share Posted January 20, 2013 except by placing a larger or smaller enclosure in the vehicle than the test enclosure you have now changed the interior cabin air space and more than likely your RF as well. THERE IS NO BUILD LOG! 1998 Chevy Silverado ext cab Alpine CDA-9887 4 Team Fi 15s 2 Ampere Audio TFE 8.0 2 Ampere Audio 150.4 3 Digital Designs CS6.5 component sets Dual Mechman 370XP Elite alternators inbound! 8 XS Power d3400 6 XS power d680 Second Skin Stinger Tsunami Wiring Sky High A Real Voltmeter not a piece of shit stinger. Link to comment Share on other sites More sharing options...
CleanSierra Posted January 21, 2013 Report Share Posted January 21, 2013 except by placing a larger or smaller enclosure in the vehicle than the test enclosure you have now changed the interior cabin air space and more than likely your RF as well. I actually had YOUR build(for some reason) in mind. A MONSTER enclosure dramatically affects resonant frequency. That test also obviously only applies to a trunk(boot) install. Im not the one you want to try to troll. Just a fyi for you. Link to comment Share on other sites More sharing options...
alaskanzx5 Posted January 21, 2013 Report Share Posted January 21, 2013 except by placing a larger or smaller enclosure in the vehicle than the test enclosure you have now changed the interior cabin air space and more than likely your RF as well. I actually had YOUR build(for some reason) in mind. A MONSTER enclosure dramatically affects resonant frequency. That test also obviously only applies to a trunk(boot) install. to find it for a big build like a wall wouldnt you need to basicaly build a sealed wall blocking off as much as the cabin as the wall you plan will and put just a single speaker in its own sealed box that is apart of the wall? hope what i said is understandable, have had no sleep in the last 24+ hours so yeah. t1500bdcp 2 t2d4 15" 1 t600.4 1 t400.2 1 set p1 tweets singer alt, tons of wiring, smd vm-1, 80prs, back seat delete, still in the works, aiming for a 145-147 with the ability to play 25hz up to 50hz. Link to comment Share on other sites More sharing options...
Neckbeard Posted January 21, 2013 Report Share Posted January 21, 2013 N8,you should pin this Build log, Super slow!!: http://www.stevemeadedesigns.com/board/topic/168096-slow-neckbeards-1970-opel-gt/ Link to comment Share on other sites More sharing options...
kirill007 Posted January 21, 2013 Report Share Posted January 21, 2013 except by placing a larger or smaller enclosure in the vehicle than the test enclosure you have now changed the interior cabin air space and more than likely your RF as well. RF even changes when you get louder (or quieter), or when you change the distance from source(subwoofer) to meter. Thinking is the root of all problems... You ALWAYS get what you pay for. Link to comment Share on other sites More sharing options...
purplesyrup Posted January 21, 2013 Report Share Posted January 21, 2013 Yea there are so many factors, Im tuned to 35 hz, my amp clamps at its peak near that frequency, My car on the other hand puts out the most SPL at about 48-49 hz, no matter what, its weird, and when I achieve my max SPL at around 49 hz my amp only clamps at around 1200w I was tuned at 40 hz, still hit max SPL in the 48-49 hz area, tuned down to 35 hz, still peak at 48-49hz, with no change in SPL, only at lower frequencies I got a huge increase. So my fusion seems to love 48-49hz, I think for next season I am going to displace a few cubic feet in the barrel to lower the cubic feet and raise the port area and tuning, and see what kind of numbers I can get. I wish my car liked lower hz so I did not have to mess with it, My old grand am was all about the hz below 43, it loved it and slammed like a mofo Link to comment Share on other sites More sharing options...
n8ball2013 Posted January 21, 2013 Report Share Posted January 21, 2013 except by placing a larger or smaller enclosure in the vehicle than the test enclosure you have now changed the interior cabin air space and more than likely your RF as well. I actually had YOUR build(for some reason) in mind. A MONSTER enclosure dramatically affects resonant frequency. That test also obviously only applies to a trunk(boot) install. hehe I should actually calculate how many cubic feet is actually in front of my wall at this point. Ill put it on my list of things to do except by placing a larger or smaller enclosure in the vehicle than the test enclosure you have now changed the interior cabin air space and more than likely your RF as well. I actually had YOUR build(for some reason) in mind. A MONSTER enclosure dramatically affects resonant frequency. That test also obviously only applies to a trunk(boot) install. to find it for a big build like a wall wouldnt you need to basicaly build a sealed wall blocking off as much as the cabin as the wall you plan will and put just a single speaker in its own sealed box that is apart of the wall? hope what i said is understandable, have had no sleep in the last 24+ hours so yeah. yep you're correct. dont get me wrong this is the basic idea behind it but you will find many factors that can influence it. THERE IS NO BUILD LOG! 1998 Chevy Silverado ext cab Alpine CDA-9887 4 Team Fi 15s 2 Ampere Audio TFE 8.0 2 Ampere Audio 150.4 3 Digital Designs CS6.5 component sets Dual Mechman 370XP Elite alternators inbound! 8 XS Power d3400 6 XS power d680 Second Skin Stinger Tsunami Wiring Sky High A Real Voltmeter not a piece of shit stinger. Link to comment Share on other sites More sharing options...
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