So basically you are not looking for any type of sound quality (SQ), you just want the "stereotypical" dumb kid with a loud *** bass car? Wonderful...

In general terms, if you want it really loud, go with a single ported box and the biggest sub/amp power combination you can afford. Make sure the port exhausts inside the car and the port length is appropriate for the box and sub Q number.

One "trick" people do is aim the subs in a car with a glass hatch (like 7's), right up against the glass so that it further pressurizes the air/cabin air and makes it louder. Remember, sound is nothing more than energy traveling in a medium (air) from the point of generation to your ears. The more pressure, the louder it is, i.e., dB.

If you want to "feel" the bass, go with a bandpass (1,2,3,4,5,6th order, etc) based upon the attenuation frequency of your car or with a sealed box. Yes, all cars have a specific attenuation frequency as well, you can calculate and/or measure it. Think of a tuning fork...well the metal in your car will do the same thing but there are things that help/hinder it like glass and carpeting.

You can calculate the pathlength of the frequency you build the box to from the rear of the car to your head and adjust it so that the highest amplitude of the frequency path-length is at your head. If you've basic physics you will be able to calculate the freq. and path length.

So to answer your question basically what size sub is the best...
- that depends upon how much power you are feeding it/them
- how much surface area you plan on moving (the more sub surface area the more air will be moved)
- smaller subs are "tighter" because they have to move less to reproduce the same frequency as a larger sub, rebound faster, and require less power to electrify the maget moving the voice coil and so forth...
- it depends upon what crossover and freqency range the sub will be playing within
- it depends upon what enclosure you utilize and how it is "tuned"
- it depends upon where you install the sub enclosure as well (remember path length)

My personal preference after having done the dumb kid thing in HS and learning to emphasize sound quality in college starting with 2-15's, 2-12's, 2-10's and now 1-8" is that the single 8" is the best for sound quality and I prefer metal. I hate rap... any moron can reproduce rap bass with the least amount of effort and think they have a great sounding stereo... right.

My advice to you is to go spend some time at some local car stereo shows and if someone is nice enough, they will let you play a cd or two of your choosing in their cars. Avoid the bass people as they are only concerned with SPL and not SQ. You will not be able to hear the difference and after a song or two your ears will be shot and again, you will not be able to hear the difference for an hour or two after.

It is most likely that the SQ folks will only play a reference CD of theirs because they don't want somebody to put in some heavy bass cd and wreck their stuff. You will also get more people to allow you to listen after they have passed through the judging lanes as their EQ settings are not as critical as before the competition and they will be more likely to allow you to play around some.

I do agree that most "stereo" shops employ people who don't make any money and who's only outlet is commission, so they want to sell you everything they can whether you need it or not.

That said, my personal preference are JL Audio 8W7's (run 3, 2 in series with the 3rd in parallel), and Rockford Power 10" (Punch series are garbage). You will need a large 2 channel amp run in 1 channel mode, seeing a 4-ohm mono load. This will run any of these combinations but plan on spending around 3K for a good setup...that's an amp, subs, enclosure, wiring, capacitor, fuse/ground block, RCA's, crossover to start. You will still need a deck, speakers, an EQ and an amp for those as well, which is another X amount depending upon your tastes.

 

Turbo, I agree with you to a point. I have never been to a show that the SQ winner was running an 8! Most of then run 2-3 10's, even 2 12's. But everything else I agree with. As to the dumb kid with bass. My 15" is tuned real nice and has a good curve, but by using my headunits eq I can ponud the hell out of any car pulling next to me. Just my 2 cents.

 

So what do you guys recomend to aim the sub to the back of the hatch or to the frunt with the ports pointing to the back. I have a 12" Mtx in my hatch right now, but want to replace it with Two 8" klipsch speakers for the bass. I find the 12" mtx to boome.

gil

 

Yes, they will hit harder with three in parallel. Every speaker you add in parallel drops the resistance in the feed.

This means that you now have more power available, just make sure to size everything accordingly in terms of wattages for your amp, subs, etc. that you don't blow anything.

 

It also depends upon the show (IASCA, etc), and how people are tuning their vehicles. I have seen most people win with 2-10's or a single 12 but then the car is a dedicated SQ vehicle as well. I'm assuming that the people reading this aren't willing to sounddampen the entire interior, and everything else that goes with competing.

Actually the most interesting one I saw had a 10" in the PS floor that had the foot well cut out in a ported box but they split the ports to do a reflex bandpass (like the Bose) to the drivers and PS's side of the car so the equally got bass in the front of the car where it's supposed to be coming from. Very cool.

Dumb *** kid; I was referring to myself as well. Been there when I was a teen...then grew up and realized bigger and more wasn't necessarily better.

As to running three subs inline...you better know that if they are 4 ohm you can't do it, if they are 8 ohm you are ok to run all in parallel. Running 3 subs in parallel with a 4 ohm load from each will drop you down to 1 ohm and Orion is the only amp I'm aware of that can handle the low of resistence.

 

Turbo, thats cool. I've seen the foot whell subs before. They actualy cut out the front of the fire wall for it.
I did sound dampin the whole car for this sub. Have to say it rocks, but taste is in the ear of the beholder!

 

8's 10's 12's...depends on your preference in music
The box you choose also makes a BIG difference
If you want tight clean sound go with a smaller sub in a sealed enclosure
If you want louder make everything vibrate kind of sound...get a larger sub with some sort of ported box (make sure you get the right volumes...a ported box not made well will just sound like garbage)

Personally i like 10's...a good 10 can get as loud as I want it to...but still small enough to give great SQ.

 

All this "smaller sub give a tighter less distorted sound" is bullsh!t, If you get the right ported enclosure an 15" will sound just as 'tight' as an 8" just much louder.

People think a 15" is sloppy and isn't as fast as an 8", sorry but 30hz is 30hz. If one sub is moving slower then another it isn't playing 30hz...

I have owned all sizes of the Massive DMX lineup and I can tell you they all sound as 'tight' as each other, but the bigger the sub the more displacment ergo higher pressure and louder bass.

The advantage of an 8" is size, enclosure volume and efficiency (dependant on woofer).

 

Didn't say 12's and 15's were sloppy, just that they are not as efficient as I already stated. For the same amount of power energizing the magnet and voice coil, the larger sub has push more mass back and forth vs. an 8" for example and thus the smaller sub is more efficient.

"Tight" in my experience is based upon the enclosure only. I can get an 8" to sound sloppy if you put it in an oversized ported enclosure and a 18" to sound very crisp if it's in the properly sized sealed box with internal dampening and enough power.

 

^^wrong

30hz is 30hz...but how controlled that 30hz is has alot to do with sound quality/spl

This is why a sealed enclosure of a smaller volume isn't as loud and is punchier because of the support from the sealed airspace.

Lesson #2: A ported enclosure supports the sub less thus making the sub work harder to control itself which it's less efficient on it's own doing. This is why any old sub can't be used as a "free air" sub as it isn't built to resonate without support from an enclosure.

Oh yea...don't argue with me on this point as I'm a First class MECP certified installer and was taught at one of the best shops in the country. I've also worked in this business long enough to know that size DOES matter as well as a plethora of other factors.

 

Control of the cone movement is dependant on the suspension type. My inhuman 18" has triple soft spiders with a soft surround and is highly accurate in a 27hz ported enclosure, and a sealed enclosure. But to make the sealed enclosure sound as loud as the ported enclosure I have to feed the sub double the power. This heats the coils more and causes impedence rise which in turn results in less power output...

Long story short; sealed enclosures are much less efficient.

 

Attually the larger the sub the more efficient the output is. If you have 400watts on a 10" and 400watts on a 12" with a drop in test with a sealed box the 12" will be louder, including more low end volume, and it will peak lower.


If you want the 18" to sound really crisp put it in a 25hz ported enclosure and you will be blown away. Trust me I have been...

 

Less efficient if you're referring to the dB level you can hit....as far as control...sealed is better and as stated provides more control over the cone.
The reason you say ported is more efficient is because you don't lose the backwave of the sub..as it's able to leave via the ports and give you a dB gain in volume (this is why ported boxes have to be more accurate so that the backwave doesn't cancel out the frontwave)....but ONLY volume, you DO lose some control from the lack of support for the cone.

 

Exactly. If he understood what a ported enclosure really does he'd understand what happens at or near the resonance frequency...

Anything done incorrectly will sound like crap. Some people have been convinced that they like loud, muddy distorting crap but that's only because they don't know any better. If your goals are merely SPL or using the most drivers you can stuff into the car, that's easy. Given enough power anybody can make really loud crap

Mulitple drivers do have advantages. For a given amount of air displaced two drivers only have to have half as much excursion as a single driver would. Less excursion means slower speed of the cone and therefore less distortion at higher power levels. Larger vs. smaller drivers have the same advantages with the exception that the cone of the larger driver is heavier. The downside to multiple drivers is that now you have two (or more) drivers you must power and enclose and at lower volumes it's overkill. My single 10" will already play loud enough to make me uncomfortable without breaking up so I don't feel the need for anything more.

There are dozens and dozens of drivers and enclosure types that can sound great, but any of them can be easily screwed up as well. There is not one almighty solution that kills everything else.

 

I have two Infinity Reference 10" subs put in where my storage compartments used to be with an unknown brand amp, then custom built the enclourses for them. I spent about $170 on the whole project and for a 16 year old with a part time job, price is important. So in response to the original post, two 8's with a nice amp would definately have enough bass to rattle your windows. But thats just my 2 cents

 

Ok how about this one for size. I like to save weight and have space to put stuff. I built a box that is actually a little too big for a set of 61/2" subs. I was really just goofing off but guess what... they hit 115 db at a local sound-off! He He They are a set of Boston 6.5s and they are powered by a Jensen 600w amp, Sony head unit. I am not joking. I am in the process of making a custom enclosure for the FD For them and replaceing amp with a better Orion unit.

Just my .02

 

Ot oh, someone pulled out the certification! AAAHHHHHHHHH! I'm also a certified MECP installer for over 9 years. So that means you know more then everyone. Many people get there knowledge by hands on not paper. I took the test without being taught by anyone. Guess what! I passed easy. So your point is? Don't argue with me, I have a piece of paper.