hello sir xtian, maayong adlaw!
here's what i posted before when there was one fellow (markzz) who wanted to look for some subs...
my comment below is for the subs he was trying to assess.
....I used to be an RF fanatic. I loved the way they packaged their products, sleek and really eye catching. on my 1st set up. I had a P2 12 sub powered by a V12 (bootleg) amplifier. was able to turn heads when cruising down the streets. was even able to cause a little rumble sa ayala basement parking, and unleash a flurry of car alarms... hehehehehe
however, when i was introduced sa other side of car audio, SQ (sound quality), the RF subs have been a let down lately.
1st they are quite pricey. 2nd, the subs they are making now, don't have the brutal durability and quality that they used to have. in short, ning mahal ang RF tungod sa ilang marketing strategies, and lesser on the engineering side.
in rating (1 to 5) of price to quality ratio, i'd say RF subs are rated 3. average..
DD on the other hand are still being hand built. they have been engineered well. if you want to play low crawling bass notes (hip - hop and R&B), you better get this sub.
DD512 will do the trick, not too pricey, but more than capable of delivering the bass. ** kindly do not use DD if you are into house, jazz, rock music. kay mabilin ang bunal niya sa baho.
one thing as well, if mugamit man gani kag DD, kindly ensure nga naa kay DAKO nga amp to power them... say around 500 watts to 1000watts. kay mabitin ka kung gamay ra ang wattage sa amp nimo.
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imo, each speaker or sub, has its own characteristics. This is just to give us car audio afficionados some benchmark on how our system would sound like.
if you want to have accurate bass you go with JL audio, Image Dyanamics, and more recently with AudioSystem.
if you want to have deep bass, go for DD, Fi, Atomic audio(have heard them, and man! they're crazy as well...) Daghan pa mang maayong brands too many to mention
if you want some punchy bass, try to go for Kicker, RF, and Firland..
of course, these subs would perform better if they will also be paired with some
good amps on the side.... class D perhaps?
by the way, box tuning may just seem one of the aspects in solving a "bilin" nga bass.
1. one could also tweak into the time alignment as well...
2. speaker phasing
hope this helps!