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keith77

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About keith77

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  1. keith77

    Help with new box for Q15 w/Bp

    Id do 4 cubes tuned to 30 hz. Sub facing up, the port facing back. and 64sqin of port. Just wondering does your back window rattle bad, my buddy has a blazer and the back window sounds horrible.
  2. keith77

    18 btl:: not moving air but...

    01 Tahoe, its about 22 square inches of port area per cubic Right now its sub up port back, port on the passanger side. and the box is diangle loading up on the passanger side (give it some more room until i move my batteries) Your port is way too big. 14 sqin per cuft is about what you want. It took me a lot of trial and error before i got my BTLs to sound like I wanted them to.
  3. keith77

    BTL 15 overexcursion

    Ive decided to build a new box. This time im going to tune at 30hz with a lot bigger port area, maybe this will fix some of the problems im running into. I think speakers facing forward sound the best also but i would lose about 2cuft of airspace to give the subs clearance. I appreciate everyones help and i will keep you posted as to how it goes. Thanks, Keith
  4. keith77

    BTL 15 overexcursion

    The frequency where it starts sounding sloppy is around 30 hz, but When i am sitting inside with the trunk closed it sounds good. the speakers are about 5 inches from the lid. Should i try a new box with more port area?
  5. keith77

    BTL 15 overexcursion

    I finally got some time to mess with the port. I tuned it down to 32hz like it was before. It sounds like the speakers are bottoming out, but I got another shop to look at them and they said it is not overexcursion, just distortion. He turned down the Xover to 80hz and he turned the gain down and it sounds a little better. The dustcaps have never got hot or smelly, the speakers just sound really distorted when i listen to them with the trunk open at 25- 30hz. When i sit inside the car it all sounds musical, 30hz is loudest (really loud) and the higher the frequency goes the weaker the bass is (60hz being not very loud). 30hz tones dont have as much excursion as the higher tones but they sound like they could be damaging the speaker. Higher tones 35-50hz sound much cleaner and have hardly any distortion. I have had audiobahn eternal 15s and Kicker L7s in a jeep cherokee and they never sounded like this, even with the back door open. Is this how they should sound. I dont want to keep playing them like this if something is wrong. Now for the the box setup. The speakers and port are facing straight up towards the trunk lid. I know everyone says to face them back, but my last box was facing back, forward, and up and i didnt notice much of a diference. So i wanted to maximize my trunk space and have the box as big as possible. The external dimensions are H23xW24xL38 and the wood is .75" thick which makes the internal volume 10.22cuft before displacements. About .5cuft for both the speakers and .1cuft for bracing. My port is a straight slot port 4"x 22.5" with a 18" length, So that makes the port displacement 1.11cuft. The total box volume is 8.5cuft after displacements (4.25 for each speaker). The only thing that might have messed me up is carstereo.com, the calculator i used to get my tuning. Scott, Nick, or anyone who has had similar issues, if you could please look over my calculations and help me resolve this issue im having, i would greatly appreciate it.
  6. keith77

    BTL 15 overexcursion

    But this was a 4cuft box tuned to 32hz on half the power that everyones running. Do i need to keep tuning lower to get it to handle the music im feeding it. The other shop i went to said it sounds fine, that its just how the speaker sounds.
  7. keith77

    BTL 15 overexcursion

    I feel really stupid for posting this and im sorry for wasting everyones time. I went up to the shop and they told me there is no way btls could bottom out with that power. They said they are bottoming out because i am listening to them with the trunk open and there is no pressure coming from the trunk lid. This is the first system ive ever had in a car and i felt like an idiot when i realized how much sense it made. the inside of the car sounds rediculous and these are some of the best speakers ive ever heard. I appreciate everyones input.
  8. keith77

    BTL 15 overexcursion

    Thanks for all your help, ill keep playing with it untill i figure something out.
  9. keith77

    BTL 15 overexcursion

    Im not sure what clamped means. I played a 50hz test tone at 0dbs when i set it with a meter. I cut about 6 inches off the port to see what would happen and it only made the problem worse (higher excursion on a 30 hz tone). It seems like the lower the tuning the less it moves on lows. should i try tuning at 30hz.
  10. keith77

    BTL 15 overexcursion

    Yes, low pass filter. No, they dont have a scope. none of the shops have a scope, they all told me to use a volt meter.
  11. keith77

    BTL 15 overexcursion

    I recently upgraded to 2 BTL 15s from a 2 Qs. In a nutshell im having the same problems that i was having with the Qs, Overexcursion. I am running a MTX TA81001 to each sub, only 1500 watts. The total volume of the box after displacements is 8.5 cubes, port is around 100sq inches and is tuned to 32hz. SSF is set at 30hz, HPF is set at 150hz, Bass boost is set at 0, and volt meter reads 38 volts which should make the amp put out 1500 watts. I went to my local shop (Pure Pressure Audio) where everyone who works there runs FI. They said i need 6 or more cubes for each speaker, and my box is causing them to move as much as they are. I built the box to FIs specs and it doesnt sound right. Can anyone help me.
  12. keith77

    BTL 15s box help

    Theres a formula but its kind of confusing. I went to carstereo.com, they've got port lenght calculator. Just plug in numbers and it will tell you how long your port should be for the tuning you want. I dont know if its accurate, thats why im tryin to get some help from the pros.
  13. keith77

    High Output alternator

    Everyone says Excessive Amperage is one of the best but theyre expensive. I was quoted $500 for a 300 amp alternator, but you never hear bad things about them. You can go to excessiveamperage.com or realmofexcursion.com where they have a forum.
  14. keith77

    BTL 15s box help

    Ive got 2 BTL 15s and i wanted to make sure my calculations were correct before i started building. The total room i have to work with is h=23 w=24 l=39inches. Total internal volume is 10.5 cubes, and after all displacements i have 8.65 cubes. the port dimensions are h=22.5 w=4.5 l=18.4 which should make the box tuned to 33hz. can someone check this for me to make sure i didnt make any errors. Thanks Keith
  15. keith77

    FI Q 18 OR BL IVE SEARCHED BY THE WAY!

    I could care less about mid bass also. i do like a sub that can get loud at both 30hz and 60hz, wich is what ive seen from the BTL. Most music doesnt get recorded at 20 - 30hz unless its chopped and screwed, and thats where the Qs shine the most.
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