Impious

Just because a good woofer has a custom recone, it doesn't mean it continues to be a good woofer with the new "custom" parts on it. Half of the time the people with those "custom" woofers don't even know the T/S parameters of the woofers they've created (or purchased). The performance of a subwoofer is a result of the sum of it's parts. A good motor without the original parts but instead a "custom recone" done will not necessarily have performance anywhere close to the original. You are assuming the performance will be identical between the two. This is not necessarily the case. Just because you tossed a recone into the motor of a w6v2 does not mean you will have performance equivalent to that of a w6v2 unless you used parts identical to the original. So no, you are not necessarily going to get the "same thing" for $100 instead of $250. You may have an operational subwoofer, but that doesn't mean it will be equal in performance to a w6v2 just because you used that motor. LOL....yeah, right. So, tell me, how about did you go about designing this new custom driver to improve results over the original? I've ranted about this before, but this ridiculous "recone boner" going around the forums leaves n00bs like yourself under the delusion that anyone can just mix-n-match parts onto a motor and come out with great results. It's not the case. Half of the people with these "custom subs" wouldn't know a good subwoofer design or performance from their asshole, yet they parade around the forums about how great their sub is because it's "custom". There is a reason subwoofer companies spend months to years designing and testing a subwoofer before bringing it to market. It's not because they are just randomly tossing parts together like so many of these "custom recones".

You don't hear about xbl mcuh because Dan Wiggins holds the liscence to the product and he only does OEM work now. Kinda like a neo magnet, not many companies use it right? But what most people don't know is neo magnets are used on just about every small application from cell phones to the motors on the active braking on a Toyota Pruis. Mr. Sagat, if you miss Adire, I am working on 12 and 15 that achieves 24 mm of one way linear excursion with only 600 watts that might interest you. Dude, if you can make it an sq monster and it looks bland like adire products did, then I'm all in No need to wait around, the driver for you is already on the market; Exodus Audio Shiva-X2 Motor is based on the Adire Brahma. Capable of handling 1kw but certainly doesn't need it. I own and run the Shiva-X and absolutely love it. The -X2 is a little different parts wise (3" coil on -X2, 2.5" coil on the original -X) but the parameters are pretty close to the same between the two. They also have a 15" model, the Tempest-X2

No, it won't.

You may try contacting TeamPSI to see if he can get ahold of anything. Why you would want to mix-n-match parts on a good woofer like the W6v2 and in turn end up with something craptastic instead, I'm not sure. A good motor with cobbled together parts doesn't make a for good subwoofer. IMO either send it back to JL for a recone or use it as a doorstop rather than spending money on assembling random parts to create a subpar subwoofer.

That's not what happened. XBL^2 is Adire's (well, Dan's now) alone to use due to the patent they have on the technology. The reason Ascendant stopped using the technology was supposedly due to a comment Dan made on a forum that Chad didn't care for. Atleast I believe this was the public reason. I believe Chad even posted that as the reason on their website when they announced they were no longer going to be using the technology. Basically someone on SIN I believe asked why someone should buy an Adire driver over an AA driver if they both have XBL and the AA is cheaper. Dan said not all drivers are created equal and just because they have the same motor technology that doesn't make them the same driver. Chad claimed he took this as an insult and slam on his company/products and used it was the reason for dropping XBL. My guess would be AA was planning to drop the technology and found that as a good opportunity to jump ship. IIRC they had a new lineup out shortly thereafter It's still around. Just off hand the newer Stereo Integrity, Exodus Audio and CSS drivers utilize XBL^2. Adire went out of business and Dan I believe burned some bridges just before the collapse, so a lot of the "Adire supports" went by the wayside. Dan's lack of presence on most of the forums likely caused a decrease in talk about his drivers. And Adire did a lot of OEM work along with the forum presence which dissipated after Adire collapsed. So that killed some of the XBL^2 buzz as well. And then, of course, you have the simple fact that "boners" on the internet move in waves. You'll have a hot items or buzzwords tossed around for a year or two only to be forgotten and replaced by a new "boner". On top of it all, since XBL is patented you had (have) to pay Dan a license/royalty fee to use the technology which made it more expensive than a "free" topology to use, so some of the companies (like AA) that used the design opted to drop it in favor of something they didn't have to pay for. Some of this paragraph is speculation, some of it is just forum heresay......but it probably all had a hand in the reason XBL isn't talked about as much. Dan is still around and designing drivers; About ADI

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.

Subwoofer Sensitivity - SSA Car Audio Forum There is the formula for sensitivity. What will happen when Fs decreases? Sensitivity will decrease, not increase. Same with Vas. Sensitivity will move in the same direction of those two terms. If one of those two go up, so does SPL. If one of those two go down, so does sensitivity. Sensitivity is inversely correlated to Qes...as Qes increases, sensitivity will decrease. It's all a basic consequence of Hoffman's Law. If you want low frequency extension in a small enclosure (low'ish Fs, small'ish Vas, higher Qes) sensitivity will necessarily be sacrificed.

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

Interesting to see Alpine promoting BL linearity/etc on many of their products on the web. On one of their mids they had posted up a "theoretical" BL graph between their driver and a "typical" driver. That page looks like it has an actual Klippel measurement of the drivers. Much better than the typical B.S. most mass market manufacturers promote. I won't buy one simply because it doesn't fit my needs, but I wouldn't be surprised if they were good performing products.

I've never been a real advocate of the DMM method. Is it accurate? No, not really. From the get-go, the formula, you're making assumptions that will render the entire exercise futile. That "4ohm" driver will hardly ever present a "4ohm" load to the amplifier, and you're assuming that the manufacturer's rated power is accurate. Then you have the "meaurement" factor, the accuracy of the measurement itself as 95Honda pointed out. Beyond that you also have the issue of gain structure; most people use 0db which gives a gain ratio of 1:1 and also provides the lowest average output from the amplifier with a non-0db source (such as music). Richard Clark and others advocated a -10db test tone for a ~ 3:1 gain structure, which increases the average output from the amplifier when used with non-0db sources (such as music) at the risk of clipping the musical peaks (they argue that since peaks are transient and dynamic as well as the masking tones in music, any distortion from clipping won't be audible and the increased power won't damaging). But, it helps get someone newer or unsure within the ballpark. Given most people's perception that "louder is better" and/or inability to identify driver strain, they may not be able to make an educated adjustment by ear alone which potentially increases the possibility of damaging equipment. Once they are in the ballpark they can make further minor adjustment by ear with music to dial it in. It's not a perfect method, but neither is setting it by ear. Unfortunately many people do buy equipment beyond their experience (I actually can't help but laugh at the number of people who are asking about 3kw amplifiers, then ask how to set the gain or where to set the bass boost). I know you are aware that the issue isn't clipping itself, but the potential increase in average power as a result of clipping that can potentially be damaging to the drivers. The shape of the waveform doesn't matter (normalized power in your test), but the increase in power from a hard-clipped amplifier (normalized voltage in your test) can be damaging to the drivers. The latter being applicable to the discussion of the thread, which does make it a potential hazard. To quote your test;

Your questions is equivalent to asking "Ford or Chevy?" I don't know because I haven't a clue what you are actually comparing. Please read the N00b Posting Guidelines; Attention NOOBS!!!! - SSA Car Audio Forum

If the sub plays fine (output wise), I would guess it's just the measurement. Try borrowing a different DMM & compare measurements

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.

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.

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.

How does it sound to your ear? Does it sound like output is virtually non-existent, or does it sound "normal"?

The voltage likely won't be significantly higher at idle than you currently have. The purpose of a high output alternator isn't to increase voltage at idle, but to limit voltage drop when under heavy load (and typically at non-idle RPM's) by having higher current output capabilities.

First I would verify the output and what impedance his amplifier is capable of operating at. Second, it depends on what enclosure you (he) plans to use them in. The Dcon's are great budget minded subs for ported enclosures. For sealed enclosures, I think there are better options. So it would be helpful to know what your enclosure options are (sealed only, or if ported is a possibility) and if you or he are able to build a ported enclosure or have the budget to have one built. Or if you are planning to use an existing enclosure, we would need to know details of the enclosure.

Basically they are nothing like the Adire LCR's actually. Baffle width, orientation, spacing, and crossovers along with the drivers would all have to be the same for it to be basically Adire LCR's. Cosmetically the baffle looks nice. I missed that page A decent amount of money in drivers to put them in such a poor acoustic alignment

Pretty cool exhaust tip you installed there on the van. May be a little oversized, but I bet the import crowd goes crazy over it.

So remote wire from HU to relay, relay to barrier strip, barrier strip to your amps. What role does the jumper play? I'm a little lost. You would need the jumper so that that input signal to the barrier strip from a single wire is sent to all 4 inputs. Each "output" connection only has one "input", each "input/output" pair is individual. The jumper connects that the one input with the other 3 inputs. One wire to the barrier strip, the jumper connects all 4 inputs together, then wire from each output to the amplifiers. Without the jumper you would have to wire an "input wire" to each input on the barrier strip.....which sort of defeats the purpose. I don't understand the question. You would wire the turn-on lead from the headunit to the input (pin 86) on the relay.

RF's site is down so I can't look at the manual, but the dual inputs are probably to allow the option of bi-amping. You should be fine with only one channel from amplifier to crossover. The manual would explain what inputs to use.

Yes. I used a barrier strip and jumper from Radio Shack to splice the REM to my four amplifiers. One wire from relay to barrier strip, then 4 wires from barrier strip to the amplifiers. 4-Position Dual-Row Barrier Strips - RadioShack.com 8-Position Jumper - RadioShack.com