If you're in the progress of buying a new sound system and not sure which way you want to go here are some pointers to consider.(long explaination may want to get a bag of chips)
Lets do SPL first cause its the most simplest sound setup you can do, cause theres only one way of going into it. first you want Power lots of power probably a minimum of 1200 watts (now when i say 1200 watts i dont mean peak power cause that rating is pointless unless your running your system for a very very short time )RMS .To make the power you want atleast one or two capacitors depending on how serious you want to get. then to if youre doing two caps your probably gonna want to get another battery or another altenator or both. then choose whatever manufacter you want to get (rockford,pioneer,mtx,alpine,etc...) get a big box ported or unported put in the vehicle and let her rip.
To get a 100% SPL system, why bother with front speakers? No really WHY BOTHER?!!!
SPL vehicles are designed to maximize speaker output at a particular frequency, meanwhile, harnessing the vehicle’s acoustics to get the maximum sound pressure level (SPL). Since DB DRAG and other sanctioning bodies filter out frequencies below 80Hz, front components are quite inconsequential. However……
If you are intending to have a 25%/75% (SQ/SPL) system, then it’s usually recommended to go with a vented subwoofer enclosure. The placement of components, rear fill, etc speakers is basically the same. The main difference between SQ & SPL systems is the woofer enclosure.
Vented boxes are designed to provide a ‘boosted’ output with the same amplifier power. Vented enclosures (or ported) essentially make the woofer more efficient, and are about 1.5x the size of the recommended enclosure for the same woofer. The difference between sealed & vented enclosures is that sealed enclosures offer the best control of the woofer, and most balanced frequency response. Vented enclosures have a built in lump in frequency response above the port frequency.
NOTE: If you tune your vented enclosure to a specific frequency (say 38Hz), all frequencies below the port freq. will be unloaded. Basically, there is little or no resistance to movement from the box, and, therefore, your speaker will move more freely than without a port. Also NOTE: the speaker will reach it’s mechanical limit with less power than in a sealed box—so it’s very easy to damage the woofer below the port frequency.
But SQ is as you may know or not know a very serious setup and very costly, not only are you geting sound but clear sound no distortion or reverbetation from anything(interior panels, trunk vibrating)now you may say yes but you are gonna get some vibrations from sound,and you'd be right.
To get a 100% SQ system, you need your car to be sound deadened. You can use dynamat, Vblock, roofing material, bondo, silicon, wood filler, and expanda-foam--you pick. Next, you need proper placement of components & woofers.Next, you need wiring that allows adequate current transfer from your alternator to the car audio system. I recommend upgrading alternator to battery connection to 4 guage or larger, and same with battery to amps wiring.
Next you want to get a good set of front and rear components$300-350 on 2 way components
$500-650 on 3 way components (focal,mb quart, alpine etc..)probably 6 or 6.5 inch with crossover and tweeter(the tweeter should be mounted in a place where you are gonna hear it but not see it(inside the door panel or in one of the air vents)) the power from which the speakers get will not be powered from the head unit but from an amplifier.same with the rear you want a set of components (not 6x9's cause the sound reproduced from that type of speaker is not natural its more a reproduced sound that can be distorted and carries too much bass)
you do not want bass comming from the front cabin area just vocals and the higher pitches from the tweeters or horns(horns if your old school)
Now that the front end of the system complete you now go to the Subwoofer Signal processing unit and amplifier(s)
first you want a sub that sounds good not so bassy that you can feel it but that it fills the front area with a low tone not over taking the rest of the your sound.Now youll probably look at getting a EQ which is in my mind the heart of the system it controls everything from where your Db roll off is, the phase from the sub, frequencies(to setup a EQ you have to get a spectrum analyser to find the best line(im not gonna explain this yet cause its too complicated and i dont have all night to type)
and this step of finding the best line can take up to a week in changing some of the parametric values.
Now that you have that all done you must find a good amplifier(good meaning $1.50/watt to $2.5 a watt ) You want one 5 channel amp or 2 2channel and one mono or 1 4 channel and a mono(dont matter which one it is youre gonna get the same result with very little difference s cause loudness is not the key.
SQ is nice to have because you dont go def from the low tones(as much) you get very rewarding remarks from ppl who wouldnt look at a sound system as a good thing and you listen to the music you enjoy not feel the the heart stoping ear bleading noise from SPL.Im SQ systems you would be able to blast the music and actually play the music louder then spl much clearer and less of a headache.
if youve read all this stuff you are probably gonna rethink the choices youve made or maybe you like the heart stopping ear bleeding noises from you car.
NOTE SQ AND SPL done right should not only perform good but be installed neatly(no wires showing capeted box amp racksetc..)
Subject: SQ or SPL 
Fri Jan 25, 2008 8:43 pm
