What if...

 

Silver Member
Username: Jwbulger79

Florida

Post Number: 131
Registered: Nov-04
Ok. not much to read right now, so i guess i'll post something.

Alright, I havent even finished installing my new system and i'm already thinking of upgrading! This stuff is addicting:-)

Right now, im putting in a memphis st3004 75x4 amp, infinity comps, and a 12" sub in. I'm building a custom box that goes all the way accross the back of my 4runner and i was wondering...if i wanted to add a couple 8"s in the future, one on either side of the 12" would that sound good?

I have to make a seperate "compartment" for the 12 because the volume needed is less than that of the entire box that goes accross the back...if that makes sense. So i thought i could just add two smaller "copmpartments" on either side of the 12" so in the future all i would have to do is make the cutouts for the 8's and I'd be good to go.

At that point i would buy another amp to run the 12" and use the 230watts from the bridged rear channels of the amp to run the 8's.

Will that sound good? I want to get another amp for my sub eventually and I was thinking of options.

Here's something else...assuming i do get the 8's...if i get 2 svc 4ohm 8's and hook it all up with my 12" sub which will be 4ohms(2ohm dvc) - that would give me a 1.34ohm load right? that would require me to wire the two vc's of the 12 in series(to get 4ohms) and then that in parallel with the 8's(to get 1.34 ohms)-is that possible?? if not, i guess i would have to buy a 12" 4ohm svc to do that. sorry, still learning the ohms calculations.

now should i get a class D amp that is 1 ohm stable or maybe an orion hcca to push all three? or would that give too much power to the 8's and not enough to the 12 since they all get equal power? if i did that then i could bride the front and rear channels of my 4 channel amp to give my comps 115 watts instead of 75 - or would bridging add too much distortion? i guess i could get a 1ohm load out of a 2x2ohm dvc sub.

basically, looking ahead...would a 12 and two 8's all firing towards the back of an suv sound good? if so, should i get an amp to power all three and bridge the 4channel to run my comps or should i get an amp only for the 12 and use the rear channels of the 4channel to run the 8's.

anyways, just thought i would put something out there to read. not much experience so i would really appreciate hearing how ya'll would approach this. thanks for the help.
 

Silver Member
Username: James1115

Wilton, Ct

Post Number: 704
Registered: Dec-04
for the best SQ it is optimal to run speakers with the same amount of surface area such as 3-12's or 10-15's lol. Can you do it the answer is yes will it sound good the systems that I have heard with that type of stuff done NO they havnt sounded good at all but hey yours could be the first. I would just do 3 chambers and add more 12's as you go you know your going to want to later anyways:-)
 

Silver Member
Username: Jwbulger79

Florida

Post Number: 132
Registered: Nov-04
thanks james. doubt I could pull off being the first to make it sound good:-) initially i wanted to add more 12's but there wont be enough volume - only enough for 8's. what if i put a bandpass crossover on the 8's and ran them off the rear channels of the 4channel amp, dedicating them to midbass?? or maybe i could mount some freeair 8's in the back seat on the sides. ya'll dont hesitate in telling me if i'm way off, because i'm just pulling these ideas out of my a@@ :-)

hhmmm...any other suggestions? just looking for ways to spend more money i guess!!:-)
 

Silver Member
Username: Jwbulger79

Florida

Post Number: 133
Registered: Nov-04
"10-15's"
lol. haha just caught that.
 

Gold Member
Username: Carguy

Post Number: 1534
Registered: Nov-04
JW, what are you after? SPL or SQ? You can't have both. Well you can but it'll cost you heck of a lot more. Getting SPL is easier cause all you need are subs with high sensitivity, around 95db or more. High power amps, and lot of ear plugs.
Sound quality is a different game altogether. You not only need a perfect box for the sub, the amp also has to be high quality. Then you'll need phase shift either on the amps or a separate device. Without it, you'll have a hard time achieving balanced sound between your components and subs.
Instead of getting 12" and 2 8" subs, why not get 2 15" high quality subs? If that's not possible, try 4 8" or 10" subs.

 

Silver Member
Username: Jwbulger79

Florida

Post Number: 134
Registered: Nov-04
Isaac, i would say i'm going for SQ. i've taken your advice so far and picked up a good amp - the Memphis 16-st3004. It's 75x4 @4ohm, 115@2ohm, and 230 bridged. I know i could use a little more power, but i figured it will do ok for now. It should be here by the end of the week along with my Infinity 6000cs comps and 120 square feet of sound deadening material. I'll spend the next few weeks installing and building a custom box and amp rack, and then I'll order probably the atlas 12(gotta decide before i start building!!).

anyways, I'm just thinking ahead to my next upgrade step and trying to build accordingly. I can scratch the idea of the 8's if that is going to mess up SQ. because of space limitations, I'll probably only ever have one sub if no 8's . i had ruled out a 15 b/c i thought a 12 would be better for SQ - should i get a 15 if that is the only sub i have? What would be your(or anyone else) next step going forward from here?

on my next amp purchase i was thinking of getting an orion hcca(if you havent bought them all yet isaac) :-) and use that to run my sub at 1ohm. then should i bridge the memphis to my comps or would that mess up SQ? that's why i was thinking of using the bridged rear channels and adding some midbass - thought that might pick up the gap b/w my comps and the sub, especially if i get a 15". am i correct in thinking that? does midbass need to be upfront to not mess up the imaging?

sorry for the long post. just thinking "out loud".
 

Gold Member
Username: Carguy

Post Number: 1536
Registered: Nov-04
Mid bass will work fine at the back. You might need a phase shift though. Good thing about Orion HCCA G4 amps are, they come with phase shift for individual channels (left and right). It'll help you balance out the rears with your sub.
I swear, ever since I told people about G4 amps, it's becoming harder and harder to get. As soon as I see one on eBay, it's gone before I can click the buy button. So it's not me.
 

Silver Member
Username: Jwbulger79

Florida

Post Number: 135
Registered: Nov-04
yeah, they dont last long on ebay. so midbass would work in the back? do you mean in the back seat and not in the way back next to the sub or would it work back there too if i had phase shift capabilities? if i cant get an amp that has phase shift, is there a way to get that with like an EQ or something of the sort?
 

Silver Member
Username: Jwbulger79

Florida

Post Number: 136
Registered: Nov-04
how about aiming the 8's toward the front, firing into the back of the back seat?
 

Gold Member
Username: Carguy

Post Number: 1543
Registered: Nov-04
I meant rear as in 6x9 speakers. You can buy a separate phase shift devices but most good amps will come with them.
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