Leaderboard

Welcome to the best damn forum on the internet

Little video we just finished up

I see a lot of people gettin into car audio lately with some pretty decent setups, a lot better than the average joe going to the shop to have their stuff installed. Any of you ever thought about competing? I used to be like a bunch of you... Thinking competition is too professional. Been doin it for years, know way more than what you may know... Well you know what. That's not the case at all! Many people i have met over the past several months are newcomers who have grown a lot since their first competition. You meet many people who have plenty of knowledge to share. You gain knowledge and the respect of the car audio world. I had been in the competition scene for several years before i started competing which was actually just last October at MECA, the 1st sanctioned division i have competed with. If you live on the East Coast, central to southside, there are many MECA shows to attend! I highly recommend attending and competing at these shows to gain further knowledge about your equipment, your install and your vehicle. After being to several shows, you will see how much respect you gain about the car audio world itself and tend to grow maturity-wise about the whole hobby. There are MANY of us who compete. Many of us are members here on SSA. We are here to help in anyway possible. I like to meet new competitors and existing ones because there is never enough knowledge and experience to go around If you have any questions about MECA or competition, in general, ask me before reading the rulebook. The rulebook may seem overwhelming at first. That's why you should ask a competitor to summarize things up first prior to competing so it doesn't seem like you are jumping into something you know nothing about. I hope this post brings more competitors to the MECA association as I always love to meet newcomers to the hobby. Hope to see you soon as the year progresses.

Why not on the black piece in front of the handle? Seriously Bro, you REALLY should listen to the tweeters in different spots before cutting any holes. I recommend after each time you move them, you listen while you are driving. Move them around to see what sound best in your particular ride. I suggest trying on the dash firing straight up and reflecting off the windshield, then try the A-pillars, then try along the top of the door and then try WAAAAAAAY down by the 6.5s. You will never know which spot will sound the best, BUT you owe to yourself to find out.

I have a confession ... I started out on the SSA forum very wrong. For that "I Apologise". I am a competitor at heart, been that way for years. Car and Truck shows and sound competitions. I enjoy everything about car audio and all general show n shines !!! USACI is also a very fun environment. You learn alot about the sport. Please come out to events like these and hang out and have a great time. Shizzon I support you 100% on this. I hope to compete in MECA next year, but this year I have goals in USACI. Thanks and best of luck to all competitors alike ... Randal aka THE CABLGUY ...

No, the magnets have nothing to do with XBL2. XBL2 refers to gap geometry (dual gaps). Many XBL2 drivers use single magnets. In fact, the Parthenon used single stack magnets, this was the highest stroke driver Adire ever built, the protoytpe I saw could do over 4" one way...

I didn't even crack a smile.

It's definitely not a fad. You will also find similar speakers with this tech labeled with "shorting rings" or "Farraday rings." As already touched upon, Dan Wiggins owns the "XBL" term. (As a side note, you guys remember the flashlights that were all the rage a couple years ago, the ones you shook up then used? Those are principally Farraday "motors" since the "coil" is shifted in the "magnetic gap" and can't leave it like a conventional coil can.) In layman's terms...have you ever bottomed out a sub or heard one bottom? It's not pleasant and not good for it. XBLs can't bottom out. Theoretically, you can beat the hell out of them with a ton of power without damage. They're not popular due to the XBL trademark, also because people would rather brag about putting 3000 watts into a 10. That's my opinion on the second part so like it or hate it, there it is

13,003 members SSA has been by far the best forum for me, I read topic after topic in multiple forums and found so much contradiction, flame wars, and misinformation. Then I found SSA and was like holy s***. Not only is ssa an awesome company that makes awesome products, but they offer this forum for their own competition. SSA=Best Community

Basically, the thought process goes somewhat like this. You have three amps, you add up the amperage total of those amps and choose the appropriate cable to fit the current needs. Once there, you go with fusing per cable to fit your cabling needs.

Ah-ha! So if you are running an amp with an internal fuse of, say, 150 amps, but you are running 1/0 AWG to the amp that is rated for 300 amps, you should put a 300 amp fuse in the wire instead of a 150? Just checking. I would just put a 150 in the wire. That's just extra protection over the 300 amp fuse as it will blow even sooner than the current capacity of the wire. You can always go lower than the rating of the wire, just not higher. I have a 100 amp fuse near the battery on my 1/0.

Eh? Not really sure I'm following the question. Re is the DC Resistence (DCR) of the coil. This means the measurement isn't done at a "frequency" as it's measured with direct current rather than alternating current. Bl^2/Re describes the motor force factor. Using Bl alone to compare "motor strength" can be misleading because it ignores the current through the coil which will affect how much actual "force" the motor has. Essentially dividing by Re compensates for this as a higher Re will have less current through the coil. As Re increases the ratio of Bl^2/Re will decrease. This makes comparing the "actual" force of the motor between different drivers more of an apples-to-apples comparison. There really isn't a direct correlation between Fs and Bl^2/Re as they are defined by different parts of the subwoofer (Fs by the compliance and mass, Bl^2/Re by the motor and DCR of the coil). But the force of the motor at Fs will be at it's minimum (in free air) as impedance is at it's maximum which means there is the least amount of current through the coil.

OK.... so generally the lower the Fs, the larger the Vas? It seems the tighter the suspension, the higher the Fs, which would be a decreased Cms correct? So Vas would increase with more Sd obviously, and a higher Fs driver, that would lower Cms, decreases Vas. This all assumes that Mms is the same. As Cms decreases (suspension gets tighter), the Fs would increase and Vas decrease. And as Cms increases (suspension gets looser), Fs would decrease and Vas would increase. As you said, this assumes Mms (and Sd) remain constant. Not sure if it was simply a misstatement; But a lower Mms would increase Fs. It's mass on a spring. The more mass you have on the end of a spring, the slower it will resonant. I wouldn't go so far as to say that a lighter cone = lower Vd. Generally yes a decrease in Sd will be accompanied by a decrease in Mms assuming the same cone material and thickness is used. And a smaller Sd would yield a smaller Vd. But Mms is more than just the mass of the cone. Mms is the mass of the moving assembly (cone, coil, former, etc) including acoustic load. A driver with a long coil overhung motor could have a higher Mms than a driver of the same materials but using a short-coil motor topology like XBL^2 even though they may have the same Xmax. This is a case of not drawing too many conclusions from the "all things equal" scenario. Low Mms + Low Cms would = higher Fs (light mass on a tight spring = higher resonant frequency). Or, think of it this way...since both Mms and Cms are in the denominator, Fs will be inversely proportional to both Cms and Mms. If those go down, Fs will go up. If those go up, Fs will go down. Started off good, think you may have trailed off a little there towards the latter part

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).

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.

No one can tell you how many decibels you'd gain. There IS a pole vent on the DCON. Right, 6.5" form the mounting ring. No problem inverting. No need to phase. No problem with the enclosure being close to the back wall, just not the port.