enclosure volume for speakers/sub

I am planning to install 6.5 inch (boston acoustics RM6) in the rear, 50 RMS and also 8 inch ( pair) rockford fosgate subs in the rear of my 86 4runner. I was trying to learn abt enclosure volume calculation but found that there are too many parameters! This may not be a good question to ask, but isn't there a simple rule of thumb to calculate volume based on just the speaker size and rms rating?

Also, usually they talk about enclosures for woofers (and rarely for speakers, correct me, I am too ignorant) Why? There is no standard location for rear speakers in my truck so I thought I will make enclosures for them too.

Woofer is a term commonly used instead of speaker, i don't know why, but i don't mind.

What model subs do you have? let us know this and we can determine the size enclosure needed.

Also, unfortunetly, there is no blanket statement for enclosures based on size and power rating.

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Thanks DJ, I bought a pair of Rockford Fosgate (used) 8 inch subs from ebay and the seller says they are 400 watts 8 ohms.   Also can u help me with this: I am thinking of powering them with MTX 275X, is this a good match? I also have kenwood KAC- 648s 4 channel amp. Can I power 2 Boston acoustics RM6 (50rms) AND these two subs from the same (kenwood amp) or that will be too less power?

You may also be limited in the airspace that is available behind the plastic interior panel and the metal skin of the vicle and whatever crossmembers may be there. I had one of those exact vehicle back in the day and it just wailed with what I did to it. I would mount the good 6.5" speakers up from in the doors, low in the door if you have manual window cranks and get a tweeter up high somewhere on the door. The subs should fit in a small box of up to about .8 cu.ft. and fit in between the roll bars quite easily.

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Top Secret, I can tell you but then my wife will kill me.

u r right forbidden, i have very little space btween the plastic panel and the metal. the front doors have power windows and i think the space is not sufficient for the RM6's. I was thinking abt the space near the rear seat. (there is a rectangular space with a small basket to keep things) What do u thing of that space?

alpesh

You could try mounting the subs like this guy did in back. Then mount your coaxials upfront in  kick panels or something. Use the MTX amp for the subs and use two of the channels on the Kenwood amp for the Boston coaxials.