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My Poor 3000gt Vr4-help Me Change Speakers-long!!!

Discussion in 'General Car Audio Discussions' started by peter_euro, Dec 26, 2003.

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  1. peter_euro

    peter_euro Full Member

    Using QTS as an indicator for enclosure design (which I prefer to do) I would never seal this driver. As low as it is, it screams no bottom end sealed to me. If the QTS were closer to .45 I would, but alas, .39 is ported all the way. [/b][/quote]
    The manufacturer was very very specific about NOT venting these subs... in fact they forewarned me at that time that if I vent them and any damage happens, they would not cover them under warranty... I am really not making this up... :rolleyes:
     
    peter_euro, Dec 29, 2003
    #21
  2. peter_euro

    peter_euro Full Member

    Not to try to think of any possible way you could run the Brahma's or anything, but... :p

    I was just thinking that I bet you'd have a lot of fun with running two Brahmas in Resistively Damped Operation.
    Which would give you the impedance that you want. ;)
    It wouldn't cut powerhandling in half either, since powerhandling is more a function of heat dissipation... the glue lets loose, it's not as if the wire melts, when a subwoofer thermally goes.
    There's even some comment to that end on that on that tech paper: "Because the second voice coil is undriven, it acts somewhat as an "insulator" on the driven voice coil. As such, power handling is slightly reduced. It is best to "derate" the power handling of the driver by approximately 25%."

    This might be appealing to you, because if you use a potentiometer as the resistor across the "empty" coil, you can vary the Q of the subwoofer/enclosure combo, changing the sound of the woofer on the fly... in fact, I bet you wish you could do this with those Alchemies now (although it sounds like you probably need to get a lower Q, if anything, with them... but still)! :p

    OK, I'll stop beating the Brahma drum now.

    Wow, 2400x1 is a big amp...


    I've unfortunately got no personal experience with the Illusions, but I am repeating words voiced by very satisfied Illusion owners (or those who've enjoyed them), who have stated their virtues remain in the realm of high sound quality. ;)

    Ben has actually commented that his O's are more of a SQ sub, you might consider those actually, over the A's even.
    I've only heard the A's myself - once with a prototype driver that sounded nice, but we certainly didn't stress it at all... and quite recently, two 12's sealed on a huge amount of power that didn't get as loud as I'd have imagined (we metered a 134dB), so I'd think something wasn't quite there... he did mention his gains were pretty conservatively set. At any rate, I'm basically saying I'm not much help here either. :p

    The IDmax I've heard the v.2 driver, and it really was impressive, I heard it sealed on 1200 watts, and it got up and went, and maintained it's composure. It does have a very nice suspension, the ID guys use tolerances that NASA would be proud of (which brings efficiency up there), the only downside would be a relatively traditional motor, that has a decently broad (22.1mm) but parabolic BL curve on DUMAX.
    But then again, virtually every other driver does outside the XBL2 world... so it's not a disadvantage per se. ;)



    Is the actual entire door skin itself prepped to work like a baffle?
    Those holes in the inner door skin (to access the door cavity) will allow the rear sound energy to exit, that's one potential problem... and the cancellation becomes worse and worse progressively, as the frequencies drop.
    If those are sealed up well, that's probably not the issue, though.

    I'd first try just swapping the mids, straight up. Swap the hex's mid for the ND6 mid, and see how it sounds. If you like that tweeter, use it.
    I don't know anything about the frequency response of the tweeter or the ND6, that would be one potential difficulty.
    If the ND6 reaches up cleanly beyond the crossover point you have now, then all is well. If it doesn't, then you'll either need to substitute a different mid, or replace the tweeter/crossover as well.
    And I shouldnt' say "all is well", but "all is as well as it's going to be, since you are mixing-and-matching your own comp set together anyway".. because efficiency differences are one issue that could cause mild headaches.

    Factory-built comp sets are generally nicely matched, the efficiency of the tweeter to the efficiency of the mid.
    But you may find that with a custom-built set, your tweeter overpowers the mid, sounding bright and harsh, or the opposite, where the system sounds like it's lacking detail, even if both drivers are wonderful..
    In this case, it's not the end of the world, you can build L-pads cheaply that balance efficiencies, but it's often an affair that involves trying a few out. ;) [/b][/quote]
    LOL, Geo, I just love this little Brahma not so subliminal indoctrination (especially re. the motor structure advantages that I have been actually very impressed with since the Brahmas first came out anyway... ;) ) so you are preaching to the choir in this case... :D

    BTW, after reading that tech paper, it appears to me that the idea behind that config is to alter the characteristics of the sub to make it fit in certain enclosures and "fool" the subs to see another one... (electronic polyfill, crude albeit immediate analogy comes to mind, LOL) and not to optimize the load on the amp (especially considering that 2400 watts 1 Ohm rating combined with the sometime occuring tinsel slap with Brahmas)... I would say this would be a rather risky proposition considering the initial cost of the set up...

    BTW, if Dan W. is able to modify the Brahma with some neo magnets and lose about 12 pounds of each sub, I would scrape up all my monies and buy 4 subs in a hartbeat... But considering that extra weight that the car already carries (three amps, wires, caps and that 70 lbs enclosure) that I have, I really have to watch any weight gains on an almost 4000 lbs car, LOL... I already had to modify the rear wheel well lips to stop the tire rubbing... :rolleyes:

    One thing you did not catch on BTW, my system does not use any passive crossovers (I never ever use passives because I am a control and tweaking freak, LOL)... Premier P1R has a very decent (up to 36dB on the subs) 3 way active crossover circuit that I have been using... Thus the compatibility of the drivers and their crossover points is really not that important, it is all adjustabile... :D

    Thus, I am not bound by the headaches of driver compatibility or passive crossover set up headaches... I am actually allowed to tweak it well beyond the passive crossover limitations (all my cars are like that...) As long as I do not end up with speakers that have crossover freqs too far apart, I am fine... Thus, feel free to recommend whatever you think would work... :)

    I was actually hoping you would be able to recommend some tweeters that would work well refracting sound off the windshield and be below that 3in diameter limit... The NDs have 9 mm one way excursion, BTW, so I assume they should put out a bit of lower end at decent SPL, in spite of that pure SQ reputation...

    BTW, how much do the Brahmas weigh exactly?

    It seems, if I read you right, the e12a may not be what it would like to be... Am I understanding this correctly? And this is the only eD driver that has both the power rating and the impedance that I could use... :(

    How would you expect ND12s to perform in this box? How would the relatively high Fs (in the 30s) of both Magnum D2 and ND12 affect their frequency response?
    ND12 has only 15mmm of xmax, thus I guess it would not be a good candidate for my set up, or is this not the case?
     
    peter_euro, Dec 29, 2003
    #22
  3. geolemon

    geolemon Full Member

    Well, I actually just calculated the reference efficiency for the Brahma and the 15A for another thread over on CAF (Fryguy's thread... he started one with the same title here on CAT today)...
    And the reference efficiency for the 15A was 0.59% efficient, while the Brahma only calculated out to 0.32%

    The reference efficiency estimates what percentage of the wattage fed into a sub actually ends up working towards moving the cone (the rest being burned up as heat). Normal subwoofers are generally only around 1% efficient.
    Per Hoffman's Iron Law the normal trade off (assuming you have a pretty firm idea of what you want the frequency response plot to be, and you are trying to keep that as constant as possible) is that as you make the subwoofer more of a "small box sub", you trade off efficiency.
    Both of these are pretty small box subs, which shows in their low reference efficiencies.
    So in that light... maybe neither of these subs are for you!

    What about something like the IDmaxes?
    Or four Shivas even? Or IDQ's? etc. Many choices when you have about 1.5 cu.ft. sealed to offer each.

    The Brahmas weigh about 45 pounds for each 12" sub. Not lightweights.

    One tweeter that I'd suggest trying is a Peerless soft-dome that's on www.madisound.com "sale page"... I actually own four of them, it's a beautiful tweeter. And on sale for $16 each, it's hardly a big risk for you to try out. It's a 4 ohm tweeter, but it does use ferrite magnets, and as such has that "home audio" format.
    {edit} I just measured them, they have a 4" face plate on them, although it is removable (it's there for mounting purposes), the magnet structure is just under 3"... hefty little guys, for 1" domes :p

    The Magnum I haven't played with, haven't modelled it.
    Generally, subs with higher resonant frequencies can be less likely to be compatible with sealed applications... it's the numerator in the EBP calculation.
    Also, subs with either higher BL's or lower Qes's (indicating a stronger motor) are less likely to be sealed-box-subs (it drives Qts, and is also the denominator in the EBP calculation).

    So what I'd guess you would be looking for would be a subwoofer with as low of an Fs as you can find, that's got a medium-to-high Qes (or Qts) value.. somewhere in the 0.4 or higher range. B)
    And you'd like a pretty low Vas, also, relatively speaking, so it'll not just work OK, but excel in your existing enclosure. ;)
    Maybe the Shivas...
     
    geolemon, Dec 29, 2003
    #23
  4. sandt38

    sandt38 Full Member

    The shipping wieght is 45 pounds or so. The actual drivers are ~38 pounds.
     
    sandt38, Dec 29, 2003
    #24
  5. Electrodynamic

    Electrodynamic Full Member

    The Magnum's were designed to have (and they do have) a flat response in a typical car environment sealed. They model the way they do because of that. Ported, on the other hand, yields a rather ample amount of bottom-end...enough to satisfy even the heaviest bass-head.

    The drivers do weigh a significant amount, however, weighing-in at 32 lbs each. They're not lightweights by any means, but their performance more than makes up for their weight.

    Every single sealed Magnum we have RTA's has yielded a flat response down to, if not lower than, 20 Hz (our measuring system doesn't go below 20 Hz very acurately). With numerous sealed driver setups the response has typically been +2/+4 dB at 20 Hz, but nothing overbearing.
     
    Electrodynamic, Dec 30, 2003
    #25
  6. peter_euro

    peter_euro Full Member

    Geo, here are the specs on Illusion Audio ND12... According to your explanation, this driver has all of the characteristics I would need... Except for the xmax... I am just curious wha these things are really capable of doing...

    VC dB W Z Re Le Ce Fs Vas Qms Qes Qts Xmax Cutout
    mm 2.8V mH F Hz li mm mm
    75mm 96 400 4 3.4 1.0 82 26 102 6.2 .28 26 ±15. 282

    I have also looked at the Max Fidelity silks sold by solen because they are almost exactly 3in in diameter... here are the specs...

    30mm 90 80 4 3.4 .10 8.2 1440 1.5 3.8 1.1

    I have looked at the Peerless you suggested but the cut out would have to be more than my total opening so I cannot use them...:(



    I am getting such a big headache from this whole thing with so many choices and no personal experience with any of these drivers, very very depressing... Weight wise both the Shiva and ND have the overhelming advantage ab about 15 and 13 lbs respectively... I could pick up the NDs right now brand new for 220 apiece, not bad at all for these things... Only Shiva is cheaper by one half... The magnum looks pretty good among the heavy weights... The IDMax looks good too and obviously can put out as well... Brahmas are too deep unfortunately and even heavier...

    I really appreciate taking your time and explaining so many things to me, I like to think I knew something before but I can see that I knew only just enough to screw up again, LOL... So it seems that I am looking at potentially carrying either 50 lbs less from the Alchemies or up to 60 lbs more, dependin on the choice of drivers... LOL, I have not had a headache like this for a long time...
     
    peter_euro, Dec 30, 2003
    #26
  7. peter_euro

    peter_euro Full Member

    Not sure what you mean by that typical car environment (trunk or hatch) but I have noticed that the trunk is way more complimenting and forgiving to the subs than the hatch... Are these drivers even available right now? And with that high fs how will they work in a hatch? This really sucks I cannot even see any of these subs...
     
    peter_euro, Dec 30, 2003
    #27
  8. sandt38

    sandt38 Full Member

    You mention the NDs excessively They are good woofers, but relatively minor output. If you are looking to save weight and money I reccomend the Shiva or the IDQ. Both are great lightwieght low cost SQ drivers. The primary differances being in enclosure size (1.5 per will work great with the Shivas, but the IDQs will need a bit of air displaced in the enclosures, about 1 foot or so per is great), and low extension. The Shiva will flat out hand the IDQ it's ass in low extension, but the transient responce of the IDQ is undeniable. The Shiva gets amazingly deep, and gets going pretty quick. The IDQ is amazingly quick, but it is not a low bass driver.

    You mention saving weight but I like the dual brahma situation Geo mentioned. I do understand your concern for power, but as I illustrated before, the 2 drivers seeing 600 per in 1.5 feet per will do great. As Geo said, the plugging of the holes is cool too. I saw him do it in his Civic install, or something similar anyways. Looked clean and intentional, not like a mistake.

    The mids are tough. I have issues suggesting such shallow mids. I feel your pain, as I had to do some work to pile my mids in there too.

    Ummm, if you wanna hear a Shiva I may be able to work something out with you. PM me if you are interested. I have mine sitting here right now not in use.
     
    sandt38, Dec 30, 2003
    #28
  9. geolemon

    geolemon Full Member

    Xmax on the Illusion isn't nearly as limiting as I thought it was - based on other people's comments about them. 15mm is hardly "piddly". Although powerhandling isn't that high, possibly that's people's concern.
    But the Qes indicates a very STRONG motor, actually... again, I'm surprised!
    I wouldn't have guessed that. That would indicate it actually being best suited in a ported box, generally speaking.
    Also would indicate it should be quite an efficienty driver - ie. 400w should be plenty to reach big output.
    These certainly look more appealing than I thought they would.
    I'm honestly not sure what would make these drivers notyield big output. Sounds like they should.
    And you'll have FOUR of them anyway, that'll give you monster sized output anyways.

    With the rave reviews that the Shivas get though, and the lower price, and more excursion, and seemingly better "fit" in a sealed application... I might still be tempted to go that route.

    But there is something very cool about the Illusion drivers, and this possibly will be your last chance to get your hands on them. And they aren't that expensive really anyway.

    Probably hard to go wrong either way. ;)

    And there's the Magnum, which "a flat in-car response when sealed" sure sounds appealing also, and it's known for it's high output capabilities.

    Again, with the subs you're narrowed down to, I wouldn't have such a big headache.
    See if there are other appealing features about them, because the performance should be good with any of them. The decision probably should come from other factors, in this case. B)

    Or just throw a dart. :p

    I'm not familiar with the Solen tweet...
    That's not a 3" dome, right? 3" face you are saying, I assume?
     
    geolemon, Dec 30, 2003
    #29
  10. MValley70

    MValley70 Full Member

    Now for my imput.....Ya'll say alot in ya'lls replies and i will admit that i didn't read it all and if i say something that has already been said i am sorry :p

    Well first off about you current subs....seein the pic of the box empty....looks like the box is not chambered off.....I thought it was a big no no to have a common chambered sealed box......can someone comment on this?

    About the sub choices......seems that your amp is holding you back......have you thought about selling the Concept amps and getts some other ones....amybe some ppi's to match your front stage amp?......Nothing against concept (From what i hear they are beasts with the power) but why not go 2 1000+ watt amps at 1ohm and get 2 super subs (like Brahmas....Geo ;) ) and run both of those amps at 1 ohm to the brahams or SI mags or ED A's or IDMAX's......and since your concerned with weight....get 2 of those super subs and either port them....or seal them.....I am sure even any of those subs sealed with 1000 watts each will be enough SPL for you in that hatch......I am sure you could sell that amp locally for a pretty good price since it is 2400 clean watts

    Yuo could shape that box on the inside to whatever cu ft you need....so we can work with that.

    As far as your front stage......Geo recommended the Vipers on SD for $140....and then he said later that they had neo mags which have shallow mounting deapths as you know.....and they are at a crazy price....there is a guy on CAF that said they are the best speakers he has ever heard....gave a big review on them....prefered them over the JK XR and focal K2's and a couple other solid sets of speakers.....but definatly look more into those Vipers.

    That is just my thoughts after reading most of this post.....hope i could help

    Scott, SC
     
    MValley70, Dec 30, 2003
    #30
  11. peter_euro

    peter_euro Full Member

    Thank you for pitching in... I read your comments and... I have heard that chambered thing from a few people before but really there is no acoustic advantage to chamber the box... the reason why some people take this route is for the time when or if one or two should blow... in a chambered box, the surviving subs would not be extra stressed under this condition... The reasons why I would not consider chambering are actually two: even more extra weight when the frigging box already weighs a ton... The other is the small obstacle of figuring out how to split the box into four chambers of the same size... easy to do on a rectangular box but next to impossible to get right in this case... If you do not get the sizing right, you may end up with each sub having a different tonal quality... not something that I would like to experience at all... ;)

    About getting the replacement amps... I do not want to even think about this considering that the sizing is very very tight for all 3 amps... Depending on the size and layout of a new amp (amps) this would may not be even possible given this very little space I have... And I really do not see a point in getting rid off this amp because it is really a great amp with lots of clean and cool power... I just do not see myself going through all of this... I am kinda burnt out dealing with systems in 3 cars at once (and this is what I am doing right now...)

    The Viper comps, I have already checked... I am way ahead of you on this one... the mounting depth is 3in... no way I could drop them right in without modifying the doors which I am very hesitant to do... I have no problem with modifying the sheet metal of the door skins but do not want to deal with the surface... The only DEI comps that fit are the actual DEI comps which I do not think are that great and I am trying to improve on HEXs... So anyway, I have spent lots of time trying to figure out this thing already... bugging others is not my preferred way of doing things... but I have come to a point where I am completely clueless, and this does not happen that often... :angry:
     
    peter_euro, Dec 31, 2003
    #31
  12. peter_euro

    peter_euro Full Member

    I had to reread your reply a few times to make sure that I fully understand your suggestions since I am sure you and Geo are extremely busy and taking the time to reply to my concerns requires a special effort on your part, and I greatly appreciate it and respect it.

    Plugging the holes and doing 2 12s would be actually way more complicated than just making a new top plate, believe it or not... The reason is very small, literally... between 0.125 to 0.25 inches... What I am saying is the Alchemies cutout diameter is 11.25in, cut out of Shiva is exactly 11 and so is IDMAX (I already checked), the others require 11.125... Seems small but it is big enough to cause the mounting holes not to line up and for the new subs not to have enough bite on the MDF... I have been through all of this, eD even sent me templates to verify this and it does seem to be the case unfortunately...

    If you look at the pic of the subs in the hatch, you can see how close to the hatch side trim pieces they come on both left and right... To use any other subs, I have to spend betw. 150 to 200 on custom CNC cut 1/8 ... steel adapter rings...because anything thicker would just not work... That price BTW would not be different for 2 or 4 rings because it is the minimum set up job charge to cut and then drill 2 sets of holes in each ring with one set being tapered to make sure that the screws are flush with the ring surface... I just did not want to go into this whole thing this because anyone would say I am nuts... but I am just truly devoted to playing music in my cars and pay price for taking my chances with Alchemies in the first place... :(

    So far only the NDs would not require the adapters because the way the holes line up, there is still enough bit and they are not heavy.... The other reason I was interested in them was because they would match the main drivers but no so sure now since I have to improvise on the tweeters anyway...

    I guess I could get a pair of 12s with a new top plate and vent them but if this is the route I am to take, I rather do 2 15s because I really hesitate switching from 4 12s to 2... I hope you can understand my hesitation... This way I rather do the 15s since I have enough volume for 2 ported (almost 3 cu ft per driver)

    I am not sure if this will make sense but my indecision is related directly to that very experienced installer who keeps telling that 15s will not respond fast enough or high enough to play rock and alt that I listen to... He insists on 4 12s in the sealed box and for some reason hates 15s... But then he is an old timer driving around with 1 JL 10in sub and set of Focals, being strictly an SQ guy... This is why I did not even considered 15s because I have no way of auditioning any at all... Everybody seems to use 10s or 12s or that cure all bass remedy W7... LOL

    I think I am going to go with the ND6 btw regardless of the subs because they play very nice at my house free air off my home stereo... I plugged in my spare hex and it did not come even close except for being louder... But with 320 watts to the front speakers, I do not think this is a problem anyway....
     
    peter_euro, Dec 31, 2003
    #32
  13. peter_euro

    peter_euro Full Member

    Xmax on the Illusion isn't nearly as limiting as I thought it was - based on other people's comments about them. 15mm is hardly "piddly". Although powerhandling isn't that high, possibly that's people's concern.
    But the Qes indicates a very STRONG motor, actually... again, I'm surprised!
    I wouldn't have guessed that. That would indicate it actually being best suited in a ported box, generally speaking.
    Also would indicate it should be quite an efficienty driver - ie. 400w should be plenty to reach big output.
    These certainly look more appealing than I thought they would.
    I'm honestly not sure what would make these drivers notyield big output. Sounds like they should.
    And you'll have FOUR of them anyway, that'll give you monster sized output anyways.

    With the rave reviews that the Shivas get though, and the lower price, and more excursion, and seemingly better "fit" in a sealed application... I might still be tempted to go that route.

    But there is something very cool about the Illusion drivers, and this possibly will be your last chance to get your hands on them. And they aren't that expensive really anyway.

    Probably hard to go wrong either way. ;)

    And there's the Magnum, which "a flat in-car response when sealed" sure sounds appealing also, and it's known for it's high output capabilities.

    Again, with the subs you're narrowed down to, I wouldn't have such a big headache.
    See if there are other appealing features about them, because the performance should be good with any of them. The decision probably should come from other factors, in this case. B)

    Or just throw a dart. :p

    I'm not familiar with the Solen tweet...
    That's not a 3" dome, right? 3" face you are saying, I assume? [/b][/quote]
    Geo, I may be thinking too much but since it seems like modifying the box to accept 4 new 12s can be very painful and with questionable results, l coud just make a new top plate to accept 2 15s, would it be possible to hook up 2 15in new Brahmas or Tumults (if they are available) into 1 Ohm load? I think this would be a way better solution than second guess an outcome with NDs or other drivers... I assume these drivers are musical enough to play along with the main drivers and still provide the extra punch when needed.... It seems that 2 15s would do a better job than 4 12s, that is provided I can get 1 Ohm out of them to my amp...

    I would just go with the ND6 plus max fidelity n30 for mains and the 2 15 Brahma for the subs... Ports can be easily added to the box if the top plate will be modified.... Either you or sandt should know the answer... This way the sound could match the looks of the car.... :rolleyes:
     
    peter_euro, Dec 31, 2003
    #33
  14. sandt38

    sandt38 Full Member

    No, they will wind up in a 2 ohm load.

    But as I said before, 2 B12s sealed with that power should yeild well beyond acceptable results. 2 B15s will definately yeild acceptable results, and so will 2 Tumults, with the proposed power.

    Also, I am not sure if you are aware, but transient responce is more directly related to Le rather than Mms as your installer seems to allude to. The ability to saturate the coil with signal more quickly will result in quicker reaction of the driver, moreso than the weight of the cone ;) . The lower the inductance, the quicker the coil saturates, the quicker it will respond to signal. Look into the Alchemies Le, and look into the Brahma 15s Le. That is one of the beautiful results of the XBL2 design. It requires a shorter coil which lowers inductance making it respond more quickly to signal. Not bad for a bunch of guys that didn't have the capital or the staff that JL had when designing the W7, eh? Here is a link that goes into more detail.

    And listen, I know you are hesitant but I assure you, the 2 B12s should yeild at least as much output as the 4 Alchemies.
     
    sandt38, Dec 31, 2003
    #34
  15. peter_euro

    peter_euro Full Member

    My amp yields only 1150 at 2 Ohms vs. 2400 at 1... It just does not seem to be enough for two 15 Brahmas and seems really not enough vs. 600 on the main channels... :(
     
    peter_euro, Dec 31, 2003
    #35
  16. sandt38

    sandt38 Full Member

    Trust me.

    The subs are rated at 1600 continuous thermal handleing. However they definately do not need 1600 to reach full capability. 600 per in 1.5 per will be plenty, go very low, and get very loud.

    However, it is apparent you are looking for reasons not to get them, which is cool. You don't need a reason. I am simply trying to lay false fears to rest.
     
    sandt38, Dec 31, 2003
    #36
  17. geolemon

    geolemon Full Member

    Well, you could also do the "RDO" wiring we discussed earlier.
    Per Adire's suggestion, you'd want to de-rate your powerhandling by about 25%... so you'd thermally be at 1200 per sub at any rate, which is what you'd be feeding them if you went that route....
    Because doing THAT, you could get your 1 ohm load. :cool:

    And I'm confident that even two 12" Brahmas would out displace your four Alchemy's now, and have better SQ. Obviously, ditto for the 15" versions.

    And actually, I don't think I responded to your previous concerns about the purpose of the RDO strategy well enough...
    It's not really like the electrical equivalent of polyfill... it's more the opposite. As you add resistance across that voice coil, you actually increase the Q of the enclosure... where polyfill technically decreases it, if you will (although some argue whether polyfill really has an effect at all).

    I thought this would match up well to two 12" Brahmas in your box, ported, because it is larger than two 12" Brahmas need, ported.
    Then, you could have fun playing with the potentiometers to bring the Q up to wherever you want. B)

    Two 15's wouldn't weigh much more, honestly. The motor is exactly the same, and the weight difference between the aluminum baskets and bigger cones is trivial.

    But it definitely sounds like the Illusions offer the easiest fit here...
    I didn't realize the mounting holes on the Alumapros were so large.
    It's definitely a deciding factor.... but I agree with your installer that it shouldnt' be a showstopper, you should be able to knock that top panel off and glue a new baffle on. Or cut out a square in that one (cutting out all the speaker holes), and sliding a new baffle in, below that one, screwing and gluing it in place, so it was actually recessed itself. ;)

    But the ND's will drop-in with no box modifications at all...
    They are supposed to yield nice SQ in sealed boxes...
    And they have the weight savings you are looking for...
    And they have a bit of that exotic "cool factor" going for them, which is always a plus in my book. :D
    It's sounding like this is certainly your easiest, most compliant to your weight and sound goals.
     
    geolemon, Dec 31, 2003
    #37
  18. peter_euro

    peter_euro Full Member

    Trust me.

    The subs are rated at 1600 continuous thermal handleing. However they definately do not need 1600 to reach full capability. 600 per in 1.5 per will be plenty, go very low, and get very loud.

    However, it is apparent you are looking for reasons not to get them, which is cool. You don't need a reason. I am simply trying to lay false fears to rest. [/b][/quote]
    actually, you are wrong... LOL... I have been thinking about this more and more, I have never discounted anything either... maybe my bud installer is not familiar with the Brahma motor topology and its ability to react very fast or he just cannot think beyond 12, I do not know... Personally, I think 2 15s would be a better way anyway since this way I would not have to deal with the side subs almost touching the hatch side trim... So no, you are not guessing right... :rolleyes: I am just a bit power hungry... this would be cutting the power in half... My bud insists that to get 15s really move it would take 2400 watts per sub (I guess this is what they have done with several 13W7 they sold and installed) and claims that single 2400 watts would not be enough, LOL... This why I am concerned... I would love to prove him wrong... :) I am pretty sure that nobody but nobody has even seen these things around here not even mentioning hearing them... I am not that young anymore (just passed 40 :( ) but I would love to blow away a few of the W7 fanatics here... LOL... honestly... No BS... I am all for Brahma... Always been (have you seen a single post were I would be picking on Adire?) :)
     
    peter_euro, Dec 31, 2003
    #38
  19. geolemon

    geolemon Full Member

    Thermal powerhandling and mechanical powerhandling are virtually unrelated.
    The thermal rating of the sub relates to how much heat it can dissipate.
    The mechanical powerhandling of the sub relates to how much input power is required to drive the sub to it's mechanical limits (excursion)... and it changes for every different box you put the sub in.
    All we've got here is thermal powerhandling. ;)

    Granted, the Brahma isn't the world's most efficient sub, but from the standpoint of "how much power will I need to be able to drive it to full excursion", we need to consider the enclosure.
    And in that respect, two 12" Brahmas will be able to be driven closer to their excursion limits than two 15" Brahmas, in the same box.
    But, the two 15" Brahmas would have a different response plot, and likely be louder (due to increased surface area, despite the decreased excursion).

    Now might be a good time to point out my experiences with my 10W6's.
    I've had them since a point in time when 1000 watts was considered an ungodly amount of power, and it would cost you $1500-$2000 to get it... and that would have been class A/B power in a monster chassis, none the less... :p Am I dating myself yet?

    Anyways, my 10W6's, thermally rated by JL at 300 RMS. And JL is known for very conservative powerhandling ratings. Others might have rated these at 500 RMS.
    I had three of them, capable of doing low-mid 140 dB's, in a box tuned to about 32hz, not going for big SPL (but getting plenty, IMO).
    They seemed to be close to their output limits (and the 1000w amp I have in there now confims it ;)) on the 400w Alpine amp that I had in there.

    So...
    Full output...
    133w per subwoofer...
    ...on subwoofers rated at 300w each (and more realistically, higher, by more conventional standards).

    Just showing how you can exploit mechanical powerhandling... because it's not a property of the woofer, it's a property that you manipulate with the enclosure.

    And in your case, simply putting the Brahma in a box that's larger than it technically needs (like the 12's), you'll get that same effect.
    Or, if you got the bigger subs (the 15's), you wouldn't need the same effect.

    Also, as regards your installer's claims to "needing" more power...
    Consider that it takes a 4x increase in power to effect a 2x increase in output/excursion.
    So, to cut your excursion in half, you'd need to drop from 1200w to 300w. Dropping from 1200w to 600w wouldn't even cut excursion by 1/4.
    Just fun stuff to ponder. B)
     
    geolemon, Dec 31, 2003
    #39
  20. peter_euro

    peter_euro Full Member

    K, let us settle this then... 2 15in Brahma II (or Tumult?) with 1150 watts or moded per Adire's tech paper into 1 Ohm and with 2400 watts (would this mod invalidate the warranty and what do I do with the potentiometers? stick them in the box or feed a wire to the outside so I can monkey with them all the time? Or just go with 4 ND12 with 2400 watts straight out of the box? It seems like these are the real 2 valid alternatives considering the (cost+weight)/effective output plus wow effect... LOL :rolleyes:
     
    peter_euro, Dec 31, 2003
    #40
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