BOTTLEDZ28

iTrader: (9)

I am trying to figure out which sub is best for me and one of things I am a little unfaimilar with is this freq. range rating on the subs. For instance, the Kicker solobarics generally range from 20-100 Hz while others range from say 50-1000. Now I understand (I think) that if the range is higher then that means that the sub would produce more noise(bass) then the others that only pick up the freq up to 100 or so. What I dont understand is where do low freq. sounds(for the subs) stop and where do the mid range speakers kick in? If the solorbaric stops at 100 and my components are rated at 50-30,000 then that means that the mid range speaker is responsible for producing music from 101-30,000 Hz right? That seems like a lot to ask for from a single 6 1/2" woofer. Would I be better of looking for a sub that say goes up a bit higher then 100? my plans are to only run a set of Polks DB's in the kicks and a single 12" sub in the rear. There will be no rear speakers at all. Is that a bad idea to not run any rear speakers at all? I plan to power my polks with the Kicker 350.2 amp and I really like the Kicker L5 and L7 12" subs.

1991 RS/SS

The sub should not be crossed over any higher than 100 Hz. Also, remember that even though the sub is rated to play to 20 Hz, the box and vehicle will greatly affect the low end output.

Realisticly, a good twelve in a vehicle will play from about 30 Hz to 80 Hz.

Your main speakers then pick up the rest (remember to cross over your main speakers at a minimum of 100 Hz High pass to avoid bottoming out the speaker at higher volumes). A small gap in frequencies between the sub and mains will not hurt because the sound is rolled off at a crossover point, not brickwalled.

The main speakers, coaxial (woofer/tweeter in one unit), or component (woofer and tweeter seperate) will typically play up tp 20,000 Hz. Remember that your ear can only hear from 20 Hz - 20,000 Hz. Dont be sold on a speaker only because it plays to 30,000 Hz, because it dosen't really matter anyway.

If low bass is important to you in a subwoofer, look for a driver with a low resonant frequency (fs). Example: 19 Hz is a good fs for a 12. Also, look for a long Xmax (linear one way excursion) to avoid distortion. A sub better suited for loud, low bass will typically have a 12.0 mm or longer Xmax.

Good, clean power, and alot of it is also critical. You will blow a sub quicker with a weak, dirty amp than a clean amp with too much power for the sub. (bass boost = blown woofer). By dirty, I mean that the amp is too small and is forced to try to make gobs of power by having the gain pegged and the bass boost on. This forces the amp to clip and send DC voltage to the sub. The DC is what will destroy a sub.

Lastly, build a good, solid box that is properly designed for the sub that is going in it. Even if two different subs are the same size, they may require a totally different box. The quality of the box is every bit as important as the sub itself.

If you are looking for higher output, go with a ported box, if you want sound quality, go with sealed.

1meanGTA

yeah you dont really need your woofers to play higher than 80 hz.

rl-p 12's = 26 mm xmax

fishboy

Like they said, some sub-woofers rate their subs far above what they should because anything over 100hz is simply not a sub-woofer, almost any sub you find will become muddy sounding past 80 hz. You can also get into directional and non-directional sound. Bass (Im sorry, I forgot what freq. range) is non-directional, to the human ear it comes from all angles, whereas mids and tweeters sound comes out more as directed beams, and that is why front speakers are kept in the front while subs can be placed in the back (and lots more airspace too!)

BOTTLEDZ28

iTrader: (9)

I do not understand what this means. Can you please break this down for me please? Also, you say to crossover my mains at a minimun of 100hz? is this done through the head unit or with external crossovers? The only crossovers I have are the ones that came with my polk component set. Are those any good for a faily decent audio setup? I am not lookng to build a monster setup here either. Just a nice good QUALITY sounding setup that makes me and my passengers happy not the people 5 blocks away. I really have my heart set on the Kicker 12" solobaric, proberbly the L5. I dont think I need the L7(750W RMS). The L5 is rated at 600W RMS and I think that is all I need to get what I want if I choose the correct amp for this speaker which will be a Kicker amp as well. I havent decided on the model yet. And like I said eariler,I do not plan on running any rear (sail panel) speakers unless someone here can tell me that doing so will make my music sound better. BTW, the sub will be going in the spare tire well.

1991 RS/SS

If you want to steer in more of a sound quality aspect, you will not install rear speakers because they screw up the staging and imaging. I only run one 12 and a pair of components in the front myself and am very happy with it.

As far as the crossover, you must run the crossover that came with the components to make them work properly and avoid blowing the tweeter. The amp that you use should have a high pass crossover built in (your deck might too, depending on brand/model), but the one in the amp is the one I was refering to in my last post. You want to set the crossover on the amp to High Pass and adjust it to 100Hz or higher. This 100 + Hz signal then goes into the input of the component crossover, then the component crossover goes to the mid and tweeter.

I will try to research the kicker 350.2 a little to possibly provide a clearer answer (let me know if you are not going to run the components with the 350.2)

Also, were you planning on building some kick panel pods for the components?

1991 RS/SS

From what I found, providing you have the kx350.2, that amp has a variable High/Low pass crossover from 50 - 200 Hz. Simply select "High Pass" and turn the dial to about 100 - 150 Hz.

As for the sub, The L5/L7 series from kicker (in my opinion, and everybody has their own) have horrible sound quality, but play more than plenty loud (I have seen quite a few L7 equipped vehicles win a number of SPL competitions, but never any SQ competitions).

I know a guy who has two 10" L5 subs in a grand am (in a sealed box) and a kicker amp. The bass is more than adequate, and really very loud for what it is, but the bass was just too muddy for me. I personally have never owned a kicker sub except for one of the very first (round) solo barics (which I was happy with).

I am probably just too fussy. I think that the L5 will probably be fine for you and make you plenty happy.

fishboy

I agree about the subs, not only do they have poor sound quality, many people complain about poor longevity as well, imo you can do much better

Jim85IROC

iTrader: (2)

Holy crap.

Let's start over.

Human ears, at the extreme, are capable of hearing from 20hz to 20,000 hz. In reality, most people can't hear much above 15k, and below 30hz. But, most music has very little content below that frequency anyway unless you like to listen to chamber music with a lot of pipe organs.

There are a lot of factors that influence a speaker's ability to play certain frequencies. To play low frequencies, you need a driver that has a lot of mass and can move a lot of air. This typically translates into large, heavy drivers with a large x-max (x-max is the distance that a driver can move back and forth in a linear manner). Because of this, low frequency reproduction also requires a lot of amplifier power.

On the other end of the spectrum, you have high frequencies. These have very short wavelengths, and because of that, you need very low-mass drivers capable of moving fast enough to play these high frequencies. You also want a driver with a small radiating area because if it's too big, your off-axis (that means the driver isn't directly facing you) response suffers.

For midrange frequencies, you're stuck in the middle and you need something that falls in the middle.

This is why most systems have multiple drivers. You have a subwoofer to handle the bass frequencies, a tweeter to handle the highest frequencies, and a midrange (or woofer or midbass - from now on I'll just call it the midbass) to handle all of the crap in the middle.

Let's start with the midrange and tweeter, since they tend to come together as a package. A typical component set will come with a 6.5" midbass and a tweeter. It'll come with a little crossover that cuts the low frequencies out of the signal going to the tweeter, and cuts the high frequencies out of the signal going to the midbass. You stick this in your kick panels and find that you've got pretty good sound overall, except that you've got no bass. Frequency response specifications that come with most speakers can be used as a rough guide ONLY. What happens to them when you stick them into your car will have a drastic effect on their real-world performance. Once they are in your kick panels, you'll have a pair of speakers that have virtually no output below 80 or 100hz, perhaps higher. I'll get into the reasons this happens later.

So... this is where your subwoofer comes into play. You need this driver to fill in the gap that your front speakers can't fill. Just like with the other speakers, there are a million subs out there with a million different specifications and gee-whiz features that usually don't mean much. Once again, the published frequency response of the subs can be largely ignored, because they're generic numbers that don't tell you much about how it'll work in your car.

One you pick your sub (I'll explain how to pick your sub in a few minutes), now you've got to make it work with the front speakers. This is where the crossover comes into play. If you remember, up above I described how the crossover for the component speakers worked. Well, you need to do the same thing in order to properly integrate the sub with the component speakers, except that in this case, it's going to get done differently. Most head units have a filter built in that performs the same basic type of function that the crossover in your component speaker does, except that it's designed to work between the subwoofer and the midbass. It does the job differently than the one that came with your components, but it's overall job is the same.

So... what frequency do you choose? It's a trial and error type of balancing act, but typically you're going to have it somewhere between 60hz and 100hz. A lot of subs can't play any higher, but even if they could, you start getting up to those frequencies that become directional, so if you play the sub any higher, it starts to pull the sound away from the front where it belongs. If you go too low with the crossover frequency, you may go below what the midbass is capable of playing, and you will put too much strain on the midbass. Remember up above that I said that lower frequencies require more excursion and more power. The smaller midbass can only do so much. I've found that typically, 80hz is a pretty good comprimise, although that's a very generic statement and certainly does not apply to all situations.

So... how do you pick a sub? That's not easy. First and foremost should be the sound quality (unless you just want to shake your fillings loose). There's only one way to determine this: Listen to it! Nothing beats an audition, whether it's in your buddy's car, or in a showroom somewhere. You want to find one that sounds detailed and clean. You want to be able to hear the different bass guitar chords instead of just boom boom boom. You want to be able to hear the difference between the bass guitar and the bass drum.

But, once you do all of that, you may want to look at one or two other factors. First of all, make sure that the subwoofer can actually play high enough to blend in with your midbass at the desired crossover frequency. This is one case where a manufacturer's published frequency response can come in handy. A lot of these massive, high-excursion subs that have massive voice coils that can handle a ton of power have a major drawback: The big voice coil has a very high inductance, which acts as a low-pass filter for the signal passing through it. In layman's terms, this means that the sub can't play higher frequencies. There are plenty of ways to eliminate this, but you typically only see them used on higher quality drivers because they can be expensive. That kicker is a good example of a sub with a high inductance, which is why it's frequency response starts to taper off at 70hz. This sub will not work well in applications where you want to use an 80hz or higher filter, which severely limits the usefullness of that sub.

Secondly, the type of enclosure is going to make a big difference. The most common type of enclosure is a sealed box. This is straightforward. It's a regular box with the sub in it. Typically these will give the flattest overall response in a car because their low frequency response tends to roll off at a much higher frequency than people realize. This sounds like a bad thing, but it's actually not. A car has a lot of cabin gain, which basically means that lower frequencies get a lot louder inside of the car. A sealed box that has a smooth low-frequency rolloff can be a good match for a car with a smooth low frequency cabin gain.

However, if you want a little extra low bass output to overcome road noise, or just because you prefer it, a ported enclosure can help. A ported enclosure is a regular box (just like the sealed one) except that it's got a port that helps boost low frequency output. These boxes will typically play much deeper than a sealed box, but below a certain frequency, their output drops off very quickly, instead of smoothly like a sealed box. In your car, when combined with the cabin gain, will give you a boosted low frequency response. Some prefer it, some don't. This is up to you.

There's a whole lot more to it than this, but I'm sick of typing, and chances are you're already so confused you're probably ready to forget it all and go buy an iPod instead. Once you start to understand some of these fundamentals though, it'll start to make a lot more sense and you'll at least be able to start asking the right questions.