95Honda

Yeah, it is a real common misconception...

Switching polarity will cause a huge change in response in the crossover region, as much as 6+ db. This can make a huge difference to your ears, especially since most 2-ways are crossed over where your ears are very sensitive (2-4KHz).... Sometimes the dip you may get from switching the polarity is just the ticket at taming a nasty peak... Or the peak you may get might help a nasty null you have in the response of the driver... And there is no right or wrong with polarity in regaurds to a 2-way, especially with 12db slopes (which alot have)... The textbook answer is simply "whatever way sounds best"....

Not exactly, you are talking about conductors vs structural wire. For non-ferrous condutors (copper, aluminum, silver, etc) it is pretty much the same. Obviously, overall diameter will change do to strand count in multiple stranded wire, but the actual cross sectional area of all the conductors combined will stay the same. The part "gauge" refers to how many passes through a die a single conductor has made from a reference point... This is also why, especially in home wiring, you see aluminum wire de-rated from copper wire of the same gauge as far as current carrying capacity. Where they would use say 12 gauge aluminum wire, they can get away with a smaller gauge of copper to do the same thing.... Here is a definition- "American Wire Gauge (AWG) is a U.S. standard set of wire conductor sizes. The "gauge" is related to the diameter of the wire. The AWG standard includes copper, aluminum and other wire materials. Typical household copper wiring is AWG number 12 or 14." -From engineering toolbox.com

KU40 pretty much hit the nail on the head. Also, don't forget that the RMS of the speaker has absolutely NOTHING to do with how much power it requires. Period. Additionally, you'll want to match the gain between the two amps as close as you can. The sole reason for this is you don't want one running out of gas before the other, and one working harder than the other (one might not last as long as the other if it is doing more of the work). If they aren't matched, they DO NOT fight each other or hurt the sub in any way whatsover, the power they produce is additive when it reaches the subs voice coil only.

Set your gain wherever you want, most of the time you can still blow the sub (easily) if your amp is powerfull enough.... That is the point I'm trying to make.... The people who usually don't get this, are the ones who blow subs when they aren't intentionally abusing their systems. If you can run an amp hard enough to destroy your subs, and don't notice a problem beforehand, there really isn't anything that can help you if you have any type of real power on tap...

It's simple. You can get full power out of just about any amp at any gain setting. It all depends on the voltage drive on the input. All the gain setting does is set the voltage gain of the amplifier. It doesn't limit power, decrease clipping, change efficiency or anything else. The sole purpose of the adjustment is to #1 gain match identical amplifiers and #2 match voltage gain to HU voltage drive maximizing S/N ratio. The later reason is hardly of concern to 99% of the people out there in car audio. Set you gain at 1/2. Lets say this is 1-2V sensitivity (pretty common). What this means is, as soon as 1-2V is present at the input of the amplifier, it will put out full power into whatever load it is driving. Most Head Units will put out 2V. Set the gain at 1/4. Lets say this is 3-4V sensitivity (again, pretty common) Again, put 3-4V on the input of the amplifier and will produce full power. There are many Head Units that will put out 3-4V, especially if you are not being judicious with the volume control, Eq settings, etc.... Now, lets say we set the gain on the amplifer to match the output of our Head Unit and not clip with our reference CD at a certain volume setting. As soon as ANYTHING is changed in the signal path, this is all out the window. This could be something as little as the CD you are listening to has a different compression technique, the vehicle's voltage has changed or you have adjusted ANYTHING on the Head Unit. Seriously, all that work and calibration is for nothing. The #1 thing that blows woofers is too much power. You have too much power when your amplifier puts out more than the woofer is rated for. You can limit the amount of power by not turning up whatever the final step in your whole signal chain is ultimately controlling the voltage drive to your amplifier. 99% of the time, this is the volume control you are touching with your fingers on your right hand. If you don't know when you are putting out too much power and keep frying subs, you need to either find a different hobby or get an amplifier that puts out less power. I say this because you can have someone calibrate, adjust, limit your system all you want, if you want it louder, you'll find a way and ulimately start pouring more power into your subwoofers... You'll either get this, or you don't. If you don't, then turn your gain down a whole bunch and sleep better at night....

You know, every time I try and explain it, a bunch of people get all fired up and refuse to make the mental leap... But, what do I know about gain adjustment/funtion, I just been building amps from scratch for the last 15 years..... LOL.....

You blew the sub from too much power. This has nothing to do with your gain setting. If you would have had the volume, bass, loudness, etc tuned down a little, it wouldn't have blown.... Don't think that when you get a new one and you turn the gain down that you are safe. You'll blow it again if your not carefull. And yes, with single sub amplifier installs there is a lot of reasons to have the gain turned all the way up, it isn't wrong at all. Especially if you have an adjustable subwoofer output. You just can't be a jakcalope with the volume knob....

Wierd, I was just talking about this in another thread.... Why not look at a similar driver with better off axis response? This is pretty much the cause of this problem... Sometimes you can get around it with different drivers, or better yet improving mounting locations.. If you want, I can get you a set of the the 6" Dayton references for about $20 a pop, they have phase plugs and better off axis response than the Mach 5. Just a thought... They look real good until about 3Khz at 30 degrees.... http://www.partsexpress.com/pdf/295-372g.pdf M5 has a good suggestion also...

The axis is the angle of the listener/measurement referenced to exactly staight into the loudspeaker. For example, 0 degrees would be like your head staring into the dustcap of the speaker. 45 degrees off axis would be you with the speaker 4' in front of you and 4' to one side, NOT pointed at you. 0 degrees would be ideal, anything less than that is not. This is beause loudspeakers (for the most part) are not ideal pointsources and vary in response depending at the angle (referenced as "axis") you are to them. The biggest problem with a conventional driver is they beam, or become more directional, as frequency and cone diameter goes up. This is what phase plugs, diiferent cone geometries, etc try and overcome. In general, the larger the cone, the more it will beam and the more cruddy the off axis response is. If you look at the off axis response of say an 18" woofer vs. a 4" mid at say, 1 Khz, you will see a huge a difference say 45 degrees off-axis. Why does this matter? Think about the last time you listened to a car stereo and you were exactly on axis with the loudspeakers? (subs don't matter because the frequencies are too low) Hardly ever, right? So, you were mostly listening off axis... Therefore if you are in this situation (like most of use) it is really important to choose drivers that have as flat of an off axis response as possible at the angle we will be to them when they are installed.... And all drivers have different off axis reponse, so try and do your homework and look for the best response, after you have nade sure everything else about the driver will work, of course... Hope this sums it up for you guys...

I'm not sure. But, Awg is Awg and it is a cross-sectional area measurement of the wire, so if they are bigger, than it isn't the same gauge... Maybe do they mean the individual conductors are bigger, with less of them? That would make more sense...

What... What.... That can't be cheap old welding cable!! Never mind it'll handle 400+ degrees (good luck with "car audio" cable here) and will resist gas, oil, crud, you name it better than anything else....

Yes, it would work just fine. Just watch the volume, if you bottom out one of those subs, you'll definetly here it.... They make a pretty loud "clank".... I'm not sure if your amp has a Sub Sonic Filter, if it does, use it, that will help a little. One of the problems with the RE series is they have alot of xmax and not a ton of xsup. But, if you bottom them out once or twice, don't freak out, they will usually be fine. Just don't repeat it over and over... I had an SPL box I had built with 8 or the RE8 subs, it would do 143db on the Term Lab with 153 watts total for all 8 subs... In my 1978 Bronco.... That was roughly $320 worth of subs at the time and $200 worth of Alpine class A/B amp.... Not too shabby really....

RE makes great gear. Any of their 10s, if you use 3 of them, would more than likely be louder than your 1 12. I have used literally almost 100 of their RE line subs, mostly the 8s. They are pretty decent for the money, they have a good amount of stroke and work well ported or sealed. Personally, I preffered them ported, they have a real strong bottom end. For the 10s, figure about just under 1ft3 for each driver, tuned around 30Hz as a great all around alignment. You can go smaller, but you'll lose efficiency and need more power. In the alignment I am suggesting, anything more than 150-200 watts per driver is overkill and will push the subs to their mechanical limits.

Honestly, I am just giving unbiased and thought out answers to help the original poster decide on what subs he would be happiest with. I also post things that may be confusing if you don't fully understand the principals of loudspeakers. If I see missinformation, I am going to pick it apart because it doesn't help anyone. Sorry if you think it is singling you out, but that is just the way it is....

Nope. Completely meaningless Please tell me your joking with this type of logic... Nope.

Going from 4.2 to 3 cubic feet = loss of efficiency = loss of output..... Tuning a little higher might help...

LOL... Why is everyone afraid to tell him the BTL is the loudest sub he could stick in his car, regaurdless of anything else?... And it sounds like that is what he wants.... He'll have the toughest time blowing those also (they do have the highest thermal capacity, do they not?)... People can say whatever they want, but of all the FI subs, the BTL models (the T/S on Bladeice at least) the loudest by a good amount... Without big batteries, without big amps, without 3 runs of 1/0..... It just costs more... I guess that might matter, but since the FI stuff is such a good price already, does it really matter? The other subs model better on the bottom octave, so if that is what you want disregaurd completely what I have said... But for sheer output in the 40+ Hz range, the loudest sub FI makes watt for watt is the BTL... I dunno, there isn't anything "mythical" or special about BTLs... They don't model wierd, in fact when I ran the T/S parameters, they say big ported box... Go figure.. And they do great in the 40-50Hz region... They are efficient, very efficient and look great for getting loud.... In fact, it models very similar to the Aura NRT-18, which I have a TON of experience with.... I know how to make that thing get loud, I am sure the BTL would be just about the same...

http://zaphaudio.com/6.5test/ Read this. It is about as unbiased as you can get. Honestly, asking about listening impressions of speakers that are mostly installed in car doors is going to be pretty tough. Most complaints you will hear anyway will be do to personal taste or install error...

You can destroy that sub, or almost any sub for that matter, with 1200 watts. The RMS have nothing to do with what a sub wants, needs or requires. It is a thermal rating of the voice coil former, wires and adhesive.... Nothing else. Box alignment, compliance, Xsusp, No and Mms have everything to do with how much power a sub needs...... Jim is 100% correct saying there is no such thing as underpowering. This is one of the stupidest terms that gets thrown around. It doesn't matter where your gain is set. Any amplifier on earth can put out full power at 1/2 gain setting, or even 1/4 with most head units these days. This is a GRAVE missconception.... A few causes of nasty noises like this are dustcaps and tinsel leads as mentioned, additionally triple joints can go bad, poorly aligned motors/coils start scraping and "clacking" when the spiders get a little worn in.... Spiders can come unglued in part from the basket and make wierd noises... I have experienced every one of these problems at one time or another.... Just start poking and proding (carefully!) until you find something broke, bent, loose or charred....

They are actually using horn loading, this is different method than a T-line. A horn acts like an acoustic transformer (sort of) by effectively coupling the acoustic output of the driver to the air very efficiently in the passband, or at least above cutoff. Horns are not very forgiving as far as design execution, but if done well are much more efficient than a T-line. A T-line on the other hand is much more forgiving as far as design and construction goes, is usually less efficient and is easier to achieve a lower cutoff with less ripple than a horn.....

Yes, a true T-line should at least have the line equal to Sd at the termination point. It isn't practicale to start with Sd because unless you are using a tube, it is impossible. This is why they are tapered to a point, usually they start out at 1.25X Sd and terminate right around Sd. T-lines don't have tuning, in fact they are very non-resonant. They have a cutoff frequency that is determained by line length and stuffing density. 6 feet of length gets you roughly around 30Hz or a little lower. The stuffing supposedly manipulates air velocity in the line and dampens resonance, usually you stuff heavily at the beginning of the line (1lb per ft3) and gradually taper to little or no stuffing the last foot or so. You stuff accordingly to smooth the impednace plot. I have built maybe 10 T-lines, all have been stuffed with Dacron or Acustastuff, every one I have seen is also stuffed. Most modeling uses stuffing. A port calculation has nothing to do with a T-line. T-lines are not for SPL. If someone has a T-line for SPL, 99% it isn't a T-line. They are non-peaky (little ripple) by nature and will not exploit the driver with huge Fr peaks if done correctly. A perfect texbook T-line would be you woofer attached to the end of a 6-8' piece of 15" diameter sonotube with about 6-7 pillows worth of stuffing inside, maybe this will help you visualize what a T-line really is, and why they are impractical in a car if they are true T-lines... Hope this helps...

Actually, you didn't built a transmission line. With the size of that rear chamber and the the size of the line, you ended up with a very low tuned ported box. The line needs to be roughly the Sd of the driver. The rear chamber needs to be as small as possible, idealy it should just be the begining of the line. Most TLs use stuffing to flatten the impedance/behave appropriately.

What didn't you like about the Alpines?

I never noticed that any of thier wire was copper clad aluminum, if that is the case, you can't even compare it. Aluminum (the cladding doesn't really amount for anything as far as DC current carrying capability) wire is much less efficient at current transfer than copper, especially at the amperages we use in car audio. Copper has roughly 1.6 times the current carring capability vs the identical cross sectional area of aluminum. So your 0 gauge Aluminum is equal to roughly 1 gauge copper..... Think about that... Aluminum is cheap, light, strong and deals with heat well, but as far as wire performance, it's way down on the list... If you are getting all copper stuff for around the same price as welding cable, then that is a decent deal. It will never have the same performance (insulation), but amp for amp will carry current just fine. I guess what really makes me go WTF is when I see things like pre-packaged Stinger 1/0 for $140 for 25'..... I just don't get that at all... The purity of copper is thrown around alot (like 99.9999 or "6-9s") but for power wire everything made we can buy is pure enough to do the job well... As far as signal goes, there can be audible, even measurable, differences. But for most of us, these differences aren't worth the extra money they cost.... The extra "grounds" you are talking about are shields on some cables. They can cut down on noise. But watch it, alot of them are used for looks/marketing ploys, so buyer beware!