Posted January 6, 200916 yr Before I yank my existing Celestion AD15H's, I'm going to try and change the porting, see if it cleans up the sound a bit. I think I'm getting excessive port turbulence, want to increase the diameter of the port to 4" from the existing 3".The specs for the AD15H's:Size : 15"Mag dia: 8.5"Mag Structure wt: 367ozMag wt: 126ozVoice Coil: 4" diaFormer: KaptonCoil winding length: .63"Magnet gap depth: .374"Coil: CopperCoil Section: RoundOverall depth: 6.7"Weight: 28.48lbsFreq resp: 30-1KMax X-over Freq: 500HzSens (1W@1m): 96Power handling: 1200 peak, 600 contNom Imp: 4 ohmsResonance (fs): 29HzResistance (Re): 2.8 ohmsPiston dia (d): 12.99"Piston area (Sd): 132.53"Vas: 7.4 cu ftTotal Dyn Mass (Mmt): 129gmsElect Q (Qes): .271Mech Q (Qms): 5.890Total Q (Qts): .260Bl product (Bl): 16.34TmPeak excursion: .157" (only 4mm!)Flux density (B): 1.33TCoil Inductanc @ 1kHz (Le): 1.6mHRecommended Alignments: 1.55 cu ft, 3" port x 11.46" long, tuned to 30Hz2.12 cu ft, 3" port x 7.79" long, tuned to 30HzMy current enclosure(s) are approximately 2.25 cu ft, with a 3" port x 8" long. I'm looking to go with a 4" port (for less turbulence), but would like to know if a different tuning frequency would give me clearer, tighter bass for the specifications given. A 4" port tuned to 30Hz is 14.86" long (for 2.12cu ft), whereas a 32Hz port is 12.67", and a 34Hz port is 10.89" - big difference between 30Hz and 34Hz.
January 7, 200916 yr Author What kind of music are you listening to mostly?Wide range, from Alter Bridge to ZZ Top, Metallica to Aerosmith. Not a lot of rap/hip-hop, but I do have some old 2Pac and Dre in the MP3 files. Have some old-school DJ Magic Mike too, but I might break that out maybe once every 3 months, just don't listen to that type of music anymore.
January 7, 200916 yr If you use your current enclosure at 2.25cuft, than you need a 4 inch port thats about 5 5/8" long which will give you a bit higher tuning to about 42hz. This will be more suitable to what you listen to.
January 7, 200916 yr Author If you use your current enclosure at 2.25cuft, than you need a 4 inch port thats about 5 5/8" long which will give you a bit higher tuning to about 42hz. This will be more suitable to what you listen to.I take it that those specs would indicate more output in the 40-50Hz range with the 42Hz tuning frequency?Won't the power handling on anything below 40Hz or so plummet like a rock? I'm guessing a subsonic filter set at 38-40Hz would be appropriate?
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