Holy Frackin' Blaster Batman, It's a monolith of 808 proportions....Chris, every tinkerer, hacker & blaster monger including me owes you a beer for this 1. That monster is over the top. You need a good 8" home stereo woofer. like maybe JBL that can hit 1KHz & still go down to maybe 40Hz on some tracks....A really well made foam surround woofer is your ticket to low end & mid-bass in the same driver. If you make the mid sockets bigger, you ruin the stock look of slick chrome which is sleek & shouldn't be modded, in my opinion. That's why you picked that box, right. Lots of room & sexy 80's chrome, right?
Woofers designed to get lower Fs, or a lower free-air resoance frequency, are less efficient by nature due to motor-mass increase, inertia & the physics behind resonances. The original Kickers FREE-AIR's you had are woefully in-efficient because their moter-mass & cone characteristics have to be heavy as 'frack' with a huge magnet & coil behind it. I'm surprised that 80's palstic held those cans. But, as a trade-off for that in-efficiency, the characteristics create a super-low fs that doesn't change much, whether it's a sealed box, infinite baffle or vented enclosure. The problem is how do you take a free-air sub & mate it with a mid-tweeter that only does about 1K & up? There's a giant mid/mid-bass hole now in your music right? With these types of woofers, the lower frequencies will draw more current causing your speaker impedance to dip down to 1-2 ohms in xtreme cases, say 20-40Hz, while 40-80 is say 2-4-ohms, for example. Translation, lots of deep-bass that almost rattles the box apart but voices are muddy & horns/guitar, etc is too tinny with no body.....
Anyway, whatever woofer you choose, high efficiency isn't everything. You need an 8" woofer that will do 40Hz-1Khz @ 4-ohms with an 'fs' or 'free-air-resonance' no higher than 50Hz. You can use 8-ohms in a pinch if the efficiency is better. Are you using crossovers at all for woofer/mid/tweeters? Alot of people say passive crossovers use alot of watts but really they keep the drivers from operating outside their range & therefore are a better load to the AMP vs having only a capacitor filter on the tweeters or running peizos. Sealing the back helps BASS carry further in the lower octaves 40-120Hz & definitely a step in the right direction.
You have all the power you need to ovecome a less efficient woofer as long as its 'fs' is low enough to overcome the cramped box when sealed. Figure out how much internal volume is available to the speakers so you can predict how your woofers will react to the sealed cabinet. Size does matter of course but big woofers in a tiny box won't get anywhere if they're tuned wrong. My GF-777Z sounds great using 2 types of woofers, 1 subwoofer - fs-38Hz & 1 Mid-Bass woofer - fs-63Hz so that a strong & even response occurs form about 45Hz to 4000Hz. You need your 8's to be pretty flat from about 45Hz-2Khz & then cross them over to the mids & highs with a 3-way crossover. Your amp has plenty of juice so a few watts traded for an even load to the amp & bettter stereo separation will do wonders for your build. Just my 2 cents....I bought 2 soundstream 2-way corssovers with a 3-Khz x-over point, a 12db/Oct. slope, rated for a 4-ohm load on the woofers/tweeters & cost me a whopping 40 bucks to ship 2 of them to my doorstep. =)
I could kiss ePay sometimes.
Maybe my mod can give you some ideas on speakers & cross-overs. The videos are low quality but you can get an idea of the clarity & bass response. I'm pretty happy overall & the crossovers are worth the effort.
viewtopic.php?f=47&t=15851
