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There's much more to it than that. First, cone area and Xmax are multiplied to arrive at a parameter known as Vd, or volume displacement. This is the amount of linear air displacement the driver is capable of achieving. The higher the Vd, the higher linear output capabilities the driver has as a larger Vd means the driver is capable of displacing more air. Second, don't confuse Xmax with excursion. They are different. Excursion is how far the cone is physically moving. Xmax is the maximum amount of linear excursion the driver is capable of achieving. Excursion is the amount of movement, Xmax is the limit of how much of that movement is "linear". Generally a driver operating at Xmax will have ~10% THD. This is typically the highest amount of acceptable performance. As you exceed Xmax it's generally considered that the distortion performance would be at an unacceptable level (among other things). In sealed enclosures, Vd is one of the important factors along with alignment and the driver's parameters in determining output capabilities. All things equal, the driver with the higher Vd will have higher output. In reality, things are never equal. So you have to look at the response of the driver in a given alignment along with your environment and available power. Having a higher Vd isn't any good if you don't have the requisite power to reach Xmax or if the driver is in an alignment that begins to roll off at a high frequency. Having a higher Vd is only a capability of higher output; whether or not you will be able to realize that higher output is dependent upon several other factors. In terms of low frequency performance, you're required to increase displacement by a factor of 4 in order to maintain a given SPL level one octave lower in frequency. This means that you need to displace 4x the air at 25hz as you do at 50hz to maintain the same SPL level at both frequencies. You can see how having a higher Xmax could be beneficial as displacement requirements increase substantially in lower frequencies. In the low frequencies Vd can be very important as it can very much limit how much linear output your system will be able to achieve. Luckily in car audio we have substantial cabin gain in the low frequencies as well, so we can maintain SPL levels at lower frequencies without having to quadruple our displacement. A 12db gain at 25hz compared to 50hz, for example, is equivalent to quadrupling your displacement. So if you have a 12db gain at 25hz compared to 50hz in your vehicle, you've already accomplished the feat. Generally you want the most cone area you can reasonably place within your space, environment and enclosure requirements. Why? A driver with a larger cone area will displace a greater amount of air for a given excursion level. This means that it takes less excursion to reach a given SPL level with more cone area. This, in turn, means that the driver(s) would ideally be operating further within it's linear range at that SPL level which, ideally, reduces distortion. This ofcourse assumes the drivers are of similar distortion performance as distortion performance will vary based on driver designs. For example, one driver may still have less distortion at 15mm than another more poorly designed driver (from a distortion perspective) driver operating at 10mm. The reason Xmax "doesn't matter" for SPL is because 1) the subwoofers are generally "burped" near tuning where excursion is minimized and 2) Xmax is a linear parameter....people competing in SPL don't really care about having higher distortion due to possibly exceeding Xmax. But that doesn't mean Xmax is not important in ported enclosures. Xmax is not a limitation on how far the driver can physically move , only on how much of that movement is linear. Also, going back to what we said about power and alignment; Xmax does not tell you how much excursion you will have in your alignment with your power. And that is what ultimately determines how much output you will have from the enclosure, any enclosure. Vd is still "important" in ported enclosure as it still helps determine which driver has the capability for higher linear output, but you have to look at your power and alignment to determine which will ultimately have higher excursion, and hence output, in use. In a ported enclosure generally enclosure size and tuning are going to have a significant impact on low frequency response and excursion with regards to frequency; but that doesn't make Xmax irrelevant for daily listening. About a half octave above tuning, the enclosure will behave similarly to a sealed enclosure meaning excursion will increase to a point that is similar to that of a sealed enclosure. Xmax may become important in this region where it's possible to reach or exceed the Xmax of the driver. That post feels like it was one giant ramble.....hopefully it makes sense.

That's the calculation for Vas. Should be pretty easy to figure out from there what will cause an increase in Vas (p is the density of air & c is the speed of sound, both of which are constants, only really need to worry about Sd & Cms) Oh, and Fs; So what happens to Fs and Vas when Cms and Sd increases? Or decreases?

Xsus = suspension limited linear excursion Xmag = motor limited linear excursion Xmax = lesser of Xsus and Xmag Xmech = mechanically limited excursion (without regard to linearity). Generally if you exceed Xmech, shit starts breaking It doesn't, really. Vas is the volume of air that when compressed to 1m^3 exhibits the same compliance as the suspension of the driver. Otherwise described as "equivalent air compliance". It's basically just another way of expressing the compliance of the driver's suspension. Larger Vas = looser suspension, smaller Vas = tighter suspension. It's most useful in determining enclosure volumes. For example, the formula for determining the enclosure size for a given sealed enclosure alignment is; Vb = Vas/([Qtc/Qts]^2-1) Basic mathematics.....since Vas is the numerator, as Vas increases the required enclosure volume (Vb) for a given alignment (Qtc) will also increase (assuming Qts stays the same).

Oh wow.....what a thread False. As M5 & others have stressed, you can not look at Fs in isolation of the other parameters as well as enclosure design. For example, a low Q low Fs driver will have anemic low frequency response in a sealed enclosure, completely contradictory to your statement.

Good to see ppl agreeing,lol. Anyways I voted everybody up +1 for helping in this topic. (execpt myself).

I am not recommending that the OP spend 5-600 bucks on an HO, BUT do think anyone contemplating adding a second battery should also concider a HO alternator as a better solution for a Daily Driver. Agreed. ::

Wow! After looking over the website they began in 1953! They do all tooling in house from coils to cones, now that is quality control. http://www.bravoxaudio.com/company.asp

First of all, that is not necessarily true. I recommend the opposite. For the amount of current you are pulling, a decent agm battery under the hood and a small secondary in the back should be fine. An alternator cannot discharge current instantaneously, although it does make a difference in larger set ups where the alternator is straining to charge the system. It is also not good for the life of a battery to be discharged everytime a large note hits. So the combo of the two is obviously the best, but with only one hundred some odd amps, the battery route will be cheaper and sufficient. If you do look at alts, there are other proven brands like powermaster, ohio generators and iraggi.

when I started working out I would drink amino acid sludge from twin lab. This stuff. LPP Protein Regular | Twinlab Or something close that probably tasted worse. It was basically acid, digestive envimes and milk protein.

Start with something insanely basic. 1 cup of this Bodybuilding.com - NOW Dextrose Powder - Corn Sugar! On sale now! With one scoop(provided in the tub) of this Bodybuilding.com - Syntrax Nectar - Best Tasting Protein! On sale now! That syntax looks good, and the dextrose is cheap, I may just try some out. I have some protein poweders building up at my place but they are cheap lol Nectrar tastes good. Like fruit. I always got apple myself. I used to take plain yogurt and add a scoop of the nectar product and that would be a really good breakfast. Then I got cheap as I was going through so much protein with 3 shakes a day so I switched to sci fit. It didn't taste half as good but it is dirt cheap. Thankfully I have always had an iron stomach and no protein ever bothered it. Some guys I knew could only have specific types that cost big $$$$.

Hey, fellow jeep owner here. I just put a 200 amp alt into my cherokee, while I did need to grind the mounting brackets a bit it went in without to much yelling and cursing. Bought it off ebay though which sounded a little sketch I'll admit but I haven't had any problems with it and my amp doesn't go into protection mode anymore. Mean Green alts are just crazy expensive. Another option could be the 160 amp alt from a 05 grand cherokee, you would just need to locate one with the right plug for the voltage regulator that matches your jeep or try to attach the wires is some fashion to the alt.

I meant more of a luck of the draw due to the tolerance of the voltage in the batteries. And sometimes when sitting for a while on a cool day I see mine sitting at 14.7, that's all I meant. Some people on here use the XS Power regulator, hopefully one of them chimes in about that, I myself am interested in it since you can set your voltage to 15.2 or something like that.

There are 12V batteries and 16V batteries that are most commonly used. To upgrade to 16V, you need a different alt, regulator, and a few extras since your electrical system is designed to work at 14.4V, not 19V. So no, just by adding a HO alt, you cannot run 16V. There would be no point in getting that extra .5 V anyway, it would be less than 100 watt difference, which you will never be close to hearing. A better box would make a bigger difference. And for that amp, a secondary battery would be enough, or a larger starting batt. A HO alt could help some but it might not be worth the money for you, but I could be wrong.

A driver can reach Xmax at any frequency. Whether or not it will depends on the power at hand and enclosure alignment. Not always true but usually a safe bet. I believe the SA8s Fs is in the 40s. Not a safe bet. Much more to it than simply the Fs.

Your voltage also depends on your batteries. A 12 V battery is normally regulated at 14.6V when fully charged on a stock electrical. A 16V battery requires a 16V alternator and will charge up to 19V. So a new aftermarket battery has a chance that it will rest higher than 12.4-12.6, and a chance that it will charge greater than 14.6V, like you sometimes may see when a voltage meter reads 14.8V. Also depends on the battery, AGM batteries shouldn't be used above 14.6V because it damages the cells. All of these numbers are plus minus some percentage but generally around here.

Theatres are always an option. Don't think SSA wants to be affiliated with illegal downloading. though, no offense. I mean I was caught by the RIAA and US district court for music 4 years ago. It was a hefty fee. Now I buy everything. Sure ways around it, but not sure if this forum is right for that question.

Start with something insanely basic. 1 cup of this Bodybuilding.com - NOW Dextrose Powder - Corn Sugar! On sale now! With one scoop(provided in the tub) of this Bodybuilding.com - Syntrax Nectar - Best Tasting Protein! On sale now!

Hmmm...I wonder if there's anywhere we could look to find Xmax vs SPL and T/S explanations... Hmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm SSA Car Audio Forum -> Technical Info & How To's

I was so scheduled with meals and vitamins I could really specialize my post work out (pedaling) and not feel like I was missing out on the whole food aspect as my other meals and suplements rounded out my food intake really well. I didn't care about flavor or mouth feel at that time, only results. Some protein out there tastes and smells like horse piss, but if it had a chance of being better, I would at least try it. I would even chew whey powder if I was going to miss a shake/meal and didn't have water or a shaker. Basically, get the highest GI sugar you can in you right after your done pedaling. Combine it with a verry fast digesting protein. Personally I felt a huge boost in my overall performance if that drink has vitamin C and I follow it up with potasium. I started with a more conventional 4:1 carb to protein mix. Then I exparaments with more carbs all the way up to a 10:1 (100grams dextrose 10 grams filtered broken down whey). I found that it made me so hungry I couldn't even make it home (if we drove to some distant trail). For me 60 grams of carbs and 30 grams of protein are just about perfect. Then 30 min after that I have another protein shake, and that will usually hold me over for about 3 hours when I would eat another meal. I got the best results with the 60:30 mix. It was easy on my stomach and it had enough carbs to really get the nutrient shuttling effects/ igf-1 that I wanted. I add in the vitamin C because it's a great antioxident and I felt helped with day after pain. There is science supporting that vitamin C will reduce endurance though. It will reduce cellular mitochondria. I took 1-3 grams a day for a year and I didn't feel held back, but YMMV. For me it felt like it along with potasium helps reduce soreness by a great deal. What you're really trying to do with the Carbs Sean is stop cortisol and get nutrients back into muscles and help clean out lactic acid too. High GI carbs after a work out the best because they stimulate insulin. Right after a work out you have high cortisol and high GH levels. The insulin spike helps to shuttle in nutrients to the cells, and now it's common beleif that by spiking insulin when your body has a high GH level you can help release lots of IGF-1 that will help build cells. The spike in insuline also stops cortisol, and that's the most important part as cortisol is what tells your body to eat muscles for energy and not fat. To be sceintific with it just get a bag of dextrose and a bag of fast acting protein. Start with the 4:1 mix and then go from there. Once you get a ration of carbs to protein down, then add in vitamins you feel might help. B vitamins, or C, etc. Creatine wouldn't hurt either. Most people will tell you it's not for endurance and only for large muscles groups and they might be right. Slowest of the muscle fbers like to eat fat. But you use almost ever muscle fiber type when pedaling with any intensity. All other muscle groups use creating and ATP for energy.

If they're in separate chambers then you're fine and don't need to take the second sub out. And I don't take offense, I probably should have elaborated in my last post. Basically with only one sub hooked up in a chamber meant for two subs, that one sub is seeing twice the volume of the box that it should. Even though you may have a (example) 2 cube box with 2 subs, when both subs are playing, each sub only "sees" 1 cube itself. However, if only one sub is playing, it "sees" all 2 cubes. Mechanical power handling decreases as box size increases because the air spring behind the sub is not as tight. As a sub plays and the cone moves, it compresses the air within the box. The more air that's in the box, the more the cone of the sub has to move to compress the air to the same pressure. Does that make sense? The compressed air within the box is acting against the cone of the sub as it moves inwards, towards the inside of the box, therefore helping to limit the excursion of the sub. Likewise, when the cone moves outwards, there is actually less pressure within the box than there is in the outside world, so that helps to suck the cone back in. However, if there is more air within the box, the sub can move farther because the pressure within the box is not building as high on the instroke and does not put as much counteracting force on the back side of the cone. To view an easy example of this take a sub out of a box and play it free air and note how high you can turn the volume knob before the sub has reached full excursion (warning, be careful as this will be with very little power). Then place the sub into the box and notice how much higher you can turn the volume knob (power) before the sub reaches full excursion. The free aired sub is the extreme of having no back pressure on the cone at all, so it moves very easily and is only dependent on the surround and spider of the sub to keep the cone from just flying off.

If those subs are in a shared chamber, do not hook only one up at a time. Very easy way to kill a sub mechanically.

cant expect him to sit on the computer all day. im sure he has a set time that he sits down and responds to them all each day, look for the email tomorrow afternoon i would guess. I thought he'd would have it set up to where he'd get alerts or some shit sent to his phone, no biggie though.. i can wait are you outta your mind.... you expect someone who is that busy to get back to you in a couple hours. you must be high.