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I was told that somebody on this forum might be able to tell me the resonance frequency of a 4runner or atleast point me in the direction of someone who knows. I need to find out so I can tune my port to match the frequency of my car. I have a 1999 4Runner SR5. Any thoughts would be greatly appreciated.
-------------------- DiRtY SoUtH DEAF SQuAD 99 4Runner 2 18" SX's hk4000d Deka g31 battery 200 amp Excessive Amperage alt all 1/0 wiring Posts: 83 | From: Georgia | Registered: Feb 2006
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Do you compete? If not...may want to rething the tuning. Would be rather boomy...tuned to where the car peaks. You may like the sound like that. Just something to thing of...
-------------------- Rob, My Ride's http://mysite.verizon.net/proaudio150/ **UPDATED 8/5** Former UsacI 301-600 Pro World Record Holder and PortWars World Record Holder (old rules). -USAC 2001 World Champion and 2001 World Finalist
"Its sometimes the journey thats fun...not the destination." Posts: 8036 | From: Huron,Oh | Registered: May 1999
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The box I was going to build is going to have interchangable ports. One will be tuned to 33hz for daily driving and the other one I would like to be tuned to my cars res. frequency for spl competitions.
-------------------- DiRtY SoUtH DEAF SQuAD 99 4Runner 2 18" SX's hk4000d Deka g31 battery 200 amp Excessive Amperage alt all 1/0 wiring Posts: 83 | From: Georgia | Registered: Feb 2006
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Hmm I know how we used to do it back when I was into competeing hard core....like I will be again. But I am going to hold off see what others say. Mainly cause I am not sure if I remember right....lol Damn Old Age.
-------------------- Rob, My Ride's http://mysite.verizon.net/proaudio150/ **UPDATED 8/5** Former UsacI 301-600 Pro World Record Holder and PortWars World Record Holder (old rules). -USAC 2001 World Champion and 2001 World Finalist
"Its sometimes the journey thats fun...not the destination." Posts: 8036 | From: Huron,Oh | Registered: May 1999
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Put a sealed box in your vehicle and test different freq. ranges on the t/l. Make sure volume and amp settings are the same on every freq. Start at 30hz or so and work your way up. Whatever freq. is the loudest on the t/l is your vehicles res. freq. Tune your comp. port close to this and you should be okay.
-------------------- Eclipse 5442 HU Modded MA HK4000d 2 Old Skool 15" Immortals for street beat. Tuned to 35hz I love the smell of burnt rubber in the mornin'! Posts: 57 | From: Backwoods, N.C. | Registered: Jan 2006
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the other thing to keep in mind is that the bigger the box the more airspace it is going to take. That will also change the frequency a little maybe 2-3 HZ. I know it did in my jeep. But like was said before you need to run a sealed box and play different notes and determine which one is the loudest. I actually made a 13.5x13.5x13.5 sealed box with a cheap 12" to do my testing. running about 150 Watts RMS to it my jeep peaked @ 44 Hz. Then Built my box for my 2-12's and tuned it to 44. then it peaked @ 47Hz. But I am still working on the design to make it LOUDER! lol
-------------------- Your Dallas/Fort Worth Stetsom Dealer. Posts: 244 | From: Arlington,TX | Registered: Aug 2005
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quote:Originally posted by SPL4life: Put a sealed box in your vehicle and test different freq. ranges on the t/l. Make sure volume and amp settings are the same on every freq. Start at 30hz or so and work your way up. Whatever freq. is the loudest on the t/l is your vehicles res. freq. Tune your comp. port close to this and you should be okay.
there is no such thing as a vehicle's resonant frequency... Secondarily the above wont work - at all. I've done a LOT of testing on my termlab in my 90 4runner and the note has been different (39hz to 59hz) with a SMALL box change! Spl remained relatively constant unfortunately...grrr
-------------------- 2005 Florida Street C Champion 2004 SBN Street C Champion 2004 SBN IDBL No Wall Champion 2003 NOPI Nats Street B Champion
posted
As mentioned, the box size will make a difference as the freq is based on remaining interior volume. Keep in mind to not open any windows as this will make a huge difference. Length of the interior determines the standing wavelength. That's why your system sounds way lower with the front windows or sunroof open.
Posts: 150 | From: W. Vancouver, BC, Canada | Registered: Aug 2002
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quote:Originally posted by p_ferlow: ...length of the interior determines the standing wavelength. That's why your system sounds way lower with the front windows or sunroof open.
Not really. The the frequency, and consequently length of the soundwave, determines initial standing wave location. Windows up there are reflections of the soundwave that are causing destructive interferiences and proabably secondary standing waves that by mere coincidence when the windows are opened (or doors) the destructive interferences are lessened.
At least that what I think...
-------------------- 2005 Florida Street C Champion 2004 SBN Street C Champion 2004 SBN IDBL No Wall Champion 2003 NOPI Nats Street B Champion
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build a large ported box that will displace an equivalent volume in your vehicle, with the subs in the same location they will be in the ported box....or 20% closer to where the port will eventually go. partially fill the box. Sometimes i just use those giant bouncy inflated balls you can get from walmart. Measure what frequency in the car does loudest on the mic at a moderate power level.
Then you tune your box below that frequency. You don't tune at the resonance. You tune the box so that it's peak output will be near resonance. If you have a small box, tune 8-11hz below resonance. If you have a large box for the woofers, tune closer to resonance
How's it going Bumpin' Yota...I hadn't seen you at any of Step and Jim's shows in a while...and now I moved up here to Columbus, OH
-------------------- World Record-Loudest SPL in my driveway Team Powermaster/XS-Power Hifonics Amps, Kicker subs-The way it should be....all were Stolen from me...boo hoo Zensky....World Domination at It's Finest www.zensky.com Posts: 3714 | From: Columbus, OH - formerly FL | Registered: Oct 2003
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bETTER LATE THAN NEVER, TO FIND THE RESONANT FREQ OF THE 4RUNNER, MEASURE FROM SHIELD TO SHIELD. EXAMP SAY IT IS 14 FT LONG, DIVIDE 1130 SPEED OF SOUND BY 14FT, AND THERE YOU HAVE 80.71 HZ NOTE NOT A PLEASANT NUMBER TO RUMBLE THE SUV BUT A ALMOST PERFECT FOR SPL TUNE YOUR PORT FOR 80 OR SO AND BURPS AWAY...
quote:Originally posted by PDpiaget: bETTER LATE THAN NEVER, TO FIND THE RESONANT FREQ OF THE 4RUNNER, MEASURE FROM SHIELD TO SHIELD. EXAMP SAY IT IS 14 FT LONG, DIVIDE 1130 SPEED OF SOUND BY 14FT, AND THERE YOU HAVE 80.71 HZ NOTE NOT A PLEASANT NUMBER TO RUMBLE THE SUV BUT A ALMOST PERFECT FOR SPL TUNE YOUR PORT FOR 80 OR SO AND BURPS AWAY...
what the heck are you talking about? tuning the box to 80hz? nah....and definitely not in an SUV. 13560/4/distance=1/4wave interior, approx 76"...1/4wave would be around 44hz. resonance probably slightly higher than that. for spl puroses in a moderate sized box, i would say to tune the enclosure around 43-45hz. and you'll probably peak closer to 50hz
-------------------- World Record-Loudest SPL in my driveway Team Powermaster/XS-Power Hifonics Amps, Kicker subs-The way it should be....all were Stolen from me...boo hoo Zensky....World Domination at It's Finest www.zensky.com Posts: 3714 | From: Columbus, OH - formerly FL | Registered: Oct 2003
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and the reason it get's louder with a window or door open is because the SYSTEM works like a ported box. the whole car is a bandpass really.
just like how a ported box will have higher INTERNAL pressure than a sealed enclosure.
in a sealed chamber, the air compresses then reacts like a spring.
in an open chamber, at moments you actually have more air inside the vehicle. more volume of a gas in a given volume means higher atmospheric pressure.
it's that simple
-------------------- World Record-Loudest SPL in my driveway Team Powermaster/XS-Power Hifonics Amps, Kicker subs-The way it should be....all were Stolen from me...boo hoo Zensky....World Domination at It's Finest www.zensky.com Posts: 3714 | From: Columbus, OH - formerly FL | Registered: Oct 2003
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quote:Originally posted by D-Bass: build a large ported box that will displace an equivalent volume in your vehicle, with the subs in the same location they will be in the ported box....or 20% closer to where the port will eventually go. partially fill the box. Sometimes i just use those giant bouncy inflated balls you can get from walmart. Measure what frequency in the car does loudest on the mic at a moderate power level.
Then you tune your box below that frequency. You don't tune at the resonance. You tune the box so that it's peak output will be near resonance. If you have a small box, tune 8-11hz below resonance. If you have a large box for the woofers, tune closer to resonance
How's it going Bumpin' Yota...I hadn't seen you at any of Step and Jim's shows in a while...and now I moved up here to Columbus, OH
i meant to say, start with a large SEALED box
-------------------- World Record-Loudest SPL in my driveway Team Powermaster/XS-Power Hifonics Amps, Kicker subs-The way it should be....all were Stolen from me...boo hoo Zensky....World Domination at It's Finest www.zensky.com Posts: 3714 | From: Columbus, OH - formerly FL | Registered: Oct 2003
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quote:Originally posted by PDpiaget: bETTER LATE THAN NEVER, TO FIND THE RESONANT FREQ OF THE 4RUNNER, MEASURE FROM SHIELD TO SHIELD. EXAMP SAY IT IS 14 FT LONG, DIVIDE 1130 SPEED OF SOUND BY 14FT, AND THERE YOU HAVE 80.71 HZ NOTE NOT A PLEASANT NUMBER TO RUMBLE THE SUV BUT A ALMOST PERFECT FOR SPL TUNE YOUR PORT FOR 80 OR SO AND BURPS AWAY...
80Hz? no way. My Blazer is around 52 Hz, not much difference in space compared to the 4runner.
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