Paradigm subwoofer diy sealed Vs/ Vented

[muddasirwaheedmalik]

Well i had two paradigm servo 15 inch 400 watts Rms Drivers.

Orginally tried them in 2.7 Cu ft sealed enclosure. could not hear much below 30 Hz without a parametric equalization boost. But still not much around 24 Hz.

BTw the driver has Fs of 18 Hz. Build two boxex 5 cufeet each one tuned toera 22 Hz and other 5 Cu Ft sealed.

Tests: Below 44 Hz the vented is a hands down winner.Signal at 30 Hz litterally sent vibrations on my first floor . The sealed was there at 30 but 3 db down. around 20 Hz could not hear the sealed not could feel it but vented at 18 HZ was being felt over my body from vented and nothing from sealed!!!!!

My question is that below 45 Hz the vented so much outperformed the sealed then why would the paradigm design a sealed system, put lots of power and equalization or am i missing something here. The subs would be used for HT exclusively. Am i missing something here ???

[Jack Caldwell]

"Servo" systems rely on motional feedback, usually via an accelerometer. When the feed back is engaged in a typical implementation, the bass output reduces at about 6dB per octave, and requires a complementary boost down to a chosen cutoff frequency. For this reason, most servo speakers have enormous amps, e.g. the 2000 Watt amps used in some of Velodyne's offerings.

When used without servo, the drivers will operate just as any other woofer, and often the bass will be more extended with a vented box.

[Jack Caldwell]

Originally Posted by muddasirwaheedmalik

My question is that below 45 Hz the vented so much outperformed the sealed then why would the paradigm design a sealed system, put lots of power and equalization or am i missing something here. The subs would be used for HT exclusively. Am i missing something here ???

To answer your question more fully, the Servo "grabs control" of the woofer cone, greatly speeding up its transient response and reducing the distortion by a very large factor, and allows use of a very small box. The best examples like some of the top Velodynes or Paradigm can be really, really good, MUCH better than the same woofers un-servoed in a large box.