Impious

I can't imagine a dust cap change would be enough of a drop in mass to increase Fs to the range you need for this driver. It appears, on a Dcon, you would need to decrease the mass by about half to get the Fs into the range you need. Which means the most logical option would be to decrease the compliance of the suspension. Would the raise in Q and decrease in Vas as a result still be acceptable to your design goals?

POWER : 1970 Watts AMP VOLTAGE (measured) : 49.25 V AMP CURRENT (calculated) : 40 A ACTUAL IMPEDANCE (calculated) : 1.23 ohms SUPPLY VOLTAGE : 12.85 V bump the voltage up a little an this beast could 800 over the rated 1500 I'm sure.... improbable but not impossible... Those numbers are even more worthless than the numbers listed on birthsheets. I really wish people would stop quoting "clamped" power. Those numbers are useless to the average user, and in no way are relevant or related to rated power. Ignore them. Forget you ever read them. They're useless, pointless, irrelevant, meaningless. And stop comparing them to "rated power".....they are not comparable!

I think that's fairly fitting and indicative of the attitude you've taken during your tenure as owner of Second Skin. I'm glad to see you'll no longer be formally associated with the company. I'm going to guess the various car audio forums you own were the beginnings of your "media empire", it's unfortunate that you won't be exiting those as well. By the way, I seem to recall you stated in a (now deleted) thread on CA.com that the company wasn't for sale, until someone posted a link, then you vanished from that conversation. Interesting. Good riddance. Hey, maybe we could even look into adding a subforum for another deadening company on SSA now as well!

I would agree with Sean that trying to use the 12" with a tweeter in a 2-way in an automobile is probably a bad idea. I would stick with a 3-way front stage and add a tweeter to cover to top few octaves if necessary.

I don't know anyone with any intelligence that would make such a recommendation. The size of the sub has nothing to do with overpowering your front stage, and there are distinct advantages to using large diameter subs.

You keep asking about subwoofers, but you've yet to tell us what your actual goals and objectives are for the system. What are you trying to accomplish? Are you focused more on sound quality or output?

has anyone heard anything about planet audio's big bang 2 series of subwoofers? the 12" has an efficiency of 95db at 1W/1M No they don't. That's called marketing. Link: Sensitivity Sensitivity (SPL) = 112 + 10*Log(9.64 * 10^(-10) * Fs^3 * Vas / Qes) SPL = 112 + 10 * LOG(9.64 * 10^(-10) * 29^3 * 39.64 / 0.586) = 84db So the actual sensitivity of the driver is a full 11db lower than advertised at 84db.

Excellent choice on subwoofer. The Gti units are solid performers. If they weren't so deep I'd probably be running one myself. As for measurements, sounds like you have the jist of things for EQ. If you want to do MLS measurements you'll need a preamp source as well.....the sound card in your computer might work if the response is reasonably flat and it has fixed timing. But for just EQ all you need is the mic and preamp. The forums on DIYMA have had a lot of good discussions and information on measuring the system. I'd suggest some searching over there when the time comes to get down to business.

0db eliminates the possibility of clipping, but as you noted results in the lowest amount of average power output. Richard Clark and many others have long suggested a -10db test tone to maximize average power output while keeping clipping at reasonable levels. This may be a little on the high side for someone who may be overpowering their drivers or are unable to recognize driver stress. -6db may be a little safer for those folk.

If the amplifier has flat frequency response, it will output the same amount of power across it's entire bandwidth. If the amplifier produces more power at higher frequencies, that means those frequencies would be louder.....that would be bad.

IMHO right now the MS-8 is a no-brainer unless you are budget-limited and/or are simply unwilling to use an auto-tune. You could probably forget about needing a microphone and RoomEQ as the MS-8 handles all of that internally and does the adjustments for you in what has been reported as a more effective and better sounding manor than any other car audio processor on the market and better than most have been able to manage with a measurement setup and months of manual tuning. Many people have exchanged their BitOne for an MS-8 with no regrets. The downside of the MS-8 is that it has no digital input, the BitOne does. But the MS-8 has balanced differential inputs (I believe) so it should still be silent. This probably sounds like a sales pitch for the MS-8, but from all reports it can do in 5 minutes equal to or better than experienced and knowledgeable users can manage in weeks or months of manual tuning, and the BitOne and 360.2 would both require manual tuning. The fellas at JBL are very smart cookies to boot, so I believe the hype. The release of the unit actually sort of sucks for me as the resale value of H701's are probably going to take a large hit as a result.....it feels sort of like the real estate crash all over again However, if you really want a measurement setup just to play with or decide to go a route other than the MS-8, there are a couple of things to consider. First, to have an accurate setup you would need to purchase a calibrated mic or have your mic calibrated. Uncalibrated mics are still useful for comparisons, but for absolute measurements calibration would need done. Second the quality of the mic preamp/etc will affect the measurements. Frequency response anomalies in the measurement electronics will affect the resultant measurements. If you want to go with a full MLS setup that measures things such impulse response as well, then you need to make sure that the signal input/output you are using have a constant timing.....I don't know the actual terminology for this, but when transmitting and recording some preamps/soundcards will have varying time delays which makes the measurements useless. You will also want to read up on and learn about audio measurements if you don't already have a solid understanding. Extracting truly meaningful data really is not as simple as sticking a mic in the car and turning on the system. Even the basics of gating the measurements, different measurement techniques, different types of measurements, so on and so forth, can create large differences in the meaningfulness or comparability of data and ultimately the necessary system adjustments and resultant sound. This is why I think the MS-8 is a no-brainer.....it takes all of this work out of the hands of the end-user and does it all internally in about 5 minutes. I've spent hours reading about system measurements and have only a very basic understanding of the differences, various considerations and ideologies, etc. I myself have a M-Audio MobilePre microphone preamp and (uncalibrated) Dayton Mic. I also have HOLMimpulse downloaded, but have yet to make the time to actually try to take any meaningful measurements with the system.

I'm not familiar with the rear deck of a '99 Altima. In one of my prior installs in an older car I owned at the time, the fabric and cardboard material of the rear deck covered the speaker holes for the rear speakers (the cardboard was perforated). Removing the material from covering the speaker hole made a significant difference. To keep it from looking hideous I just used some old 6x9 mesh grills that I had.

At what level of distortion was this measurement taken?

Sean seems far more familiar with those drivers than myself. 400hz has a wavelength of 33.75", so beaming shouldn't be an issue over that bandwidth. If I haven't posted it already, you can figure out the inductive lowpass effects with the formula; f = Re/(2*Pi*Le) *Le in Henries (it's listed in T/S as millhenries, so you'll have to convert it before working the formula) Ideally this would be 1 octave above your intended crossover frequency. The other thing I would look at is a frequency response and impedance graph. A large peak in the response and a ripple in the impedance curve can indicate cone break-up at that frequency, which would want to be avoided. Other than that......as long as it plays high enough for your needs, it should play lower than your needs since low frequency performance will be improved over a 10", so you should be good to go. And really, the increased cone area will reduce the required excursion for a given output level, so distortion at various listening levels should be lower with the 12" than a 10"

You've been able to do that without issue for a couple decades. I know I've been doing it for over a decade without a single issue. Power cable induced noise is an old wives tale in car audio

Really, just from what you've said, I would guess that the article you read was filled with techno-babble bullshit. It sounds like they were taking some general facts and extrapolating out useless or possibly incorrect theories. Stereophile'ish, for lack of a better word. Silver has less resistance than copper, no doubt about it. And while I haven't done any mathematics at all, this is a pure guesstimation, I would have a hard time imagining the silver tinning having less resistance than the copper wire of comparatively much greater thickness. Skin effect is real, and wire does have group delay. However, within the audible spectrum and with speaker wire the length we use in car audio (and in most homes), both of these issues can be completely ignored. The change in speaker wire "performance" as a result of these two items within the 20hz - 20khz bandwidth is well below the threshold of audibility. We are talking about hundredths of a decibel and nanoseconds. Nothing to concern yourself with. Now if we were talking RF frequencies, then it's something to consider. Nobody can hear the difference, but many people like to trick themselves into believing the can so they can justify either 1) spending more on speaker cable than most spend on a new car, or 2) to justify their other closely held but largely unfounded beliefs. It's a little like religion, really.....a loss of rational thinking so that irrational thinking can attempt to be justified. Also, skin effect only affects AC not DC. So no worries with your power/ground cables. This is actually a long standing debate. Some people swear by UTP (unshielded twisted pair), including the likes of Richard Clark.......others swear by shielded cable. This and amplifier sonics are probably the two most hotly debated topics.

stefanhinote askes good questions and I would agree with his premise. All things equal, and assuming you had adequate volume for each option, I would chose to go the route of the X's out of those two options. Nearly double the displacement capabilities gives that option an advantage in potential output capabilities.

Considering how many companies will not sell a recone kit to the end user, I supposed you could be happy that's even an option they offer This is my attempt at optimism

You need to get out more OP: Are you looking to buy new, used, ebay, authorized dealer? What are you trying to power?

Where has this been proven? And don't link me to a clamp test, those prove nothing.

www.ebay.com www.craigslist.com And glance through the classifieds of the various forums. Should be pretty easy for you to get a gauge on pricing.

I'm not sure if I exactly understand your question regarding "RMS vs surface area", since you mention choosing between multiple subs compared to a single driver but not many specifics to that question. But, more cone area means more SPL for a given excursion level, and less excursion for a given output level keeping the driver further within it's linear range thus decreasing distortion. There are some benefits to distributing the power between more than one motor as far as power compression is concerned (all things equal), but unless you are into SPL competitions and trying to squeeze every last decibel out you are probably better off focusing on cone area than power handling. Alternator upgrades are more related to how much power your amplifier is using than the power handling of the subwoofers. If you have a 1600w amplifier and you plan on using all 1600 watts, then electrical upgrades depend on how well your current electrical system handles that load and not the power handling of the subwoofers or how that power handling is distributed among multiple amplifiers.

Avionixx was the house brand for an electronics buildhouse called Value Electronics. Elemental Designs distributed/sold the Avionixx amplifiers back in the '04 - '05 range, until eD began offering their own line of amplifiers. Value Electronics was also the buildhouse for those early Elemental Designs amplifiers. Avionixx was a hot name on the internet until eD stopped carrying them in favor of their own branded amplifiers....Avionixx switched to a couple different resellers but I don't think it every really had the momentum it did when they are being pushed by eD. They weren't bad amplifiers. They're no Sinfoni, but no Pyramid either. Pretty middle of the road. I hadn't even realized they were still around until this thread, searching google I see they still have an active website. Interesting. Concept has been around for a while as well. They used to have some higher powered cheaper amplifiers that were all the rage back in the '03 - '05 time frame. The subwoofers weren't overly popular, however they did offer one interesting line. I believe the CSP line was design/built by RE (which means it was probably designed by Scott, the same Scott who now owns Fi ). I believe it used an XBL^2 motor. The RE Destroyers that were popular a couple years ago used the CSP motor. If your subwoofer is a CSP, it might be a pretty decent subwoofer.

I would rather have slower traffic with intelligent, helpful threads than the 10 posts-per-minute of nonsense and jackassery that some of the other forums have.

Where are you from in Indiana?