chow8400 Posted April 23, 2023 Report Share Posted April 23, 2023 (edited) Hi All, I would like to identify possible deficiencies or receive some suggestions to change the setup in my car. Its important to note I compete in the stock class, so I am limited to 2500w on the bass amp, a single battery (15v max). I have a Lexus IS250 with Factory Amp Installed and an Android Player. Last SPL Score: 140.7db (2ohm) Equipment 2 DB-SA272 12 (2ohms dvc) 1 Rockford Fosgate T2500-1BDCP 1 JL Audio TwK-88 1 XS Power PWR-S5-3400 1 Mechman 257A Alternator Big 3 upgrade 2/0 AWG Positive (12ft) and Ground (3ft) 8 AWG Speaker Wire (4ft in length) Knukonceptz Twisted RCAs I've wired the subwoofers down to 2 ohms and using speaker A (+/‐) on the Rockford to terminate the connection. I am using second skind damplifier pro mats in a single layer. An image is attached showing the rear for the trunk/sub. The top view of the enclosure is also seen, with the port. Lexus has a ski port, which the extend port of the enclosure goes through. This is due to the fact that my rear seats cannot go down. Edited April 23, 2023 by chow8400 Left out the alternator info Quote Link to comment Share on other sites More sharing options...
Joe X Posted April 24, 2023 Report Share Posted April 24, 2023 Ok a few questions: 1 do you compete with burps or music. 2 what tools you own, scope, dd-1, multimeter, clamp, spl meter, etc. 3 what are your box specs, that is net volume, tuning, port area, also if you have variable tuning. 4 your rear deck is open or closed (no open holes). Quote Link to comment Share on other sites More sharing options...
chow8400 Posted April 24, 2023 Author Report Share Posted April 24, 2023 (edited) @Joe X 1. Burps or Sweeps 2. Multimeter and SPL Meter (Oscilloscope on order) 3. Enclosure Specifications: 6.004 cu.ft³ Gross Volume 5.019 cu.ft³ Net Volume 56in² Port Area Port tuning 37hz (Fixed) 4. Open (2 holes) - Ski Port, Factory Woofer Mounting Area (on rear deck). Edited April 24, 2023 by chow8400 Corrections Quote Link to comment Share on other sites More sharing options...
Joe X Posted April 24, 2023 Report Share Posted April 24, 2023 (edited) Thank you, I do need clarification on 3 and 4: On number 3, I don't think I get your box specs correctly: I read net volume is ? (it doesn't say). port area 56 square inches. port tuning is 37Hz but fixed? or variable. On number 4 the port doesn't count as open hole because it belongs to the box airspace, I am looking for holes that connect the trunk to the cabin, like when you take away the rear deck speakers and the holes remain open. Edited April 24, 2023 by Joe X Quote Link to comment Share on other sites More sharing options...
chow8400 Posted April 26, 2023 Author Report Share Posted April 26, 2023 (edited) @Joe X 6.004 cu.ft³ Gross Volume 5.019 cu.ft³ Net Volume 56in² Port Area Port tuning 37hz (Fixed) 2 Holes (Ski Hole and Factory 8" Woofer Mount Area) Edited April 26, 2023 by chow8400 Quote Link to comment Share on other sites More sharing options...
Joe X Posted April 26, 2023 Report Share Posted April 26, 2023 So bear with me as this may get a bit long. The first step is the box, you have a big rectangle port fully internal BUT then looking at the pic you have a fully external port that is clearly smaller that I imagine goes through the ski hole and that has a different (smaller) port area and port length that you don't specify. To match your box specs you should only have a fully internal port 56 square inches in area and 16 in length. That external extension lowers the overall tuning and also reduces the port area significantly. 1 Quote Link to comment Share on other sites More sharing options...
chow8400 Posted April 27, 2023 Author Report Share Posted April 27, 2023 (edited) Heading to the workshop on Saturday. I'll provide an update then. Thanks @Joe X Edited April 27, 2023 by chow8400 Quote Link to comment Share on other sites More sharing options...
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