Question about my friends setup

[RooTxBeeR]

My friends system was the second audio system I ever heard in my life, and since no one around here has a "real" system, closest thing to one I have been in. My question is, when he plays notes that to what I hear in my experience, are out of his subs range, it sounds like they are being filtered, like you don't hear them at all. WHen he plays Put on by Jeezy, some notes bang, but the rest, you don't hear as if there is a subsonic filter. Well my friend ended up selling his car, kept the system, and said I can screw around with it till he gets a new car. I finally got to look closely at everything, and he doesn't even have a subsonic filter on the amp, no crossovers or anything. How is he able to do that with out any of that? The sub is a kenwood KFC-W2500, 360 Watts max 4 ohm single VC driver, the box has a sticker on it named Hot Box, and on the back has a Patent Pending sticker meaning its a pre fab. The box is 2 Cu, The sub is located in the center of the box, inside, with 1 side 1/2 in plexi glass, and the other end has a 2"x2" square port that is maybe 8" ci. The amp is a Alpine MRV-F250, 4 channel amp with 250 Watts, with the sub going to rear channels, I am assuming he had it bridged. With my system, I have 2 10" JBLs in a seals box on a 425 Watt amp running them in series together and when ever I play something I can't, you can hear I can't hit it.

Here are pics of all his stuff for a bit more help.

[KevinniveK]

Low pass = subsonic look again at the filters

Edit: lp = low pass (subsonic), hp = high pass

[RooTxBeeR]

I believe your wrong, I have a LPF built into my amp and one on my HU, which does not act at all like a subsonic filter.

Edit: If what your saying is a subsonic filter, the amp on sub section is set yo LP, and the dial is set yo 120Hz, so that is definatly not a low pass, because it hits bass not midbass.

[KevinniveK]

Seems as if both the hp and lp can't be turned on at the same time, that being said which one is it set to? and whats the box tuned to? 120 hz would be midbass you generally want your lp to be set a little higher than your boxes tuning

[RooTxBeeR]

It's set to LP and the dial is set to 120Hz, I do not know what it is tuned to, pre fab box.

[KevinniveK]

its probably somewhere in the mid 40s to somewhere in the 50s (box tuning)

[RooTxBeeR]

Well the front of the sub cone is in a 1 Cu sealed box, other half of the box is 1 Cu with a 2" x 2" port, about 2 " deep, about 8 Sq In of port, so I am guessing its up there in the tuning from 40-50. more than likely a fart box at 45 Hz. But I still don't know how his shit does't sound like garbage on the notes out of his playable frequancy range.

[DannyV18]

WOW.

A ssf acts as a high pass filter (filters out frequencies below setting), and the low pass filter on your head unit is a cutoff for your speakers to cut out lower than wanted frequencies.

[RooTxBeeR]

My LPF on my head unit does not cut out unwantted lower frequencies, i only have the setting 60hz 80hz 120hz and Thru, and when I switch each I hear I get higher bass from the next. And the HPF takes out the lows the front and rear channels wont receive Thru 80hz 100hz 120hz 150hz