how much power does the AV12 need?


  • Member
    dantheman on #91

    i am seriously considering getting the AV12, but I realized they only come in dual 2 ohm VC’s, and my PPI amp is only stable down to 2 ohms. So, it looks like I’d have to wire it for a 4 ohm load. My amp is rated at 200 watts at 4 ohms @ 12 volts, so it would be more like 325 watts at around 13.8 volts which is like a normal car (i think). Would this be ok, or is AE planning on coming out with a dual 4 ohm version anytime soon?

    another random question, how does the AV12 compare to the boston acoustics G5?


    Member
    PuffDaddy_d on #1708

    Since this is for your car, you may not get the output you’re looking for with only 300 watts to that sub. You’ll simply end up having to turn up the gain on the amp too high or use too much bass boost and that’s only going to lead to distortion or clipping. You may want to invest in a bigger amp.


    Member
    dantheman on #1709

    well, i dont really need a bigger amp, since it puts out around 500-600 watts at 2 ohms, i just need a sub with dual 4 ohm voice coils, like a 12w6v2, or a g512. i wish the AV12 had a dual 4 ohm model though…


    Member
    Travis Gibby on #1710

    With 200 W that sub will produce 111 dB in free field. Add to that cabin gain ~ 12 dB/octave below 80 Hz or so and you have a serious sub. 325 W will give you 2 dB more, which isn’t much. If you went up to 500 W you would be at 115 dB pluss cabin gain.

    Or you could sacrafice a little more trunk space and buy the AV15 which is almost 3 dB more sensitive, which is the equivalent of doubling your ampilfier power in terms of output.

    Travis


    Member
    dantheman on #1711

    well, i would go with av15, but I listen mainly to rock and punk, so I don’t think a 15 inch sub would give me more of that upper bass. I understand a 15 inch would still play higher frequencies, just not as loud. I personally like to cross my subs over at around 100 Hz (definitely not any higher). With 325 watts, would the AV12 be as loud and sound as good as a JL 12w6v2 thats getting 500 watts? Basically I’m trying to decide if its worth it to get a w6v2 for $100 dollars more.

    thanks for all the help, i appreciate it


    Member
    Travis Gibby on #1712

    I understand a 15 inch would still play higher frequencies, just not as loud.

    That is a popular misconception. Bandwidth is limited primarily by cone breakup which happens WELL out of subwoofer range for a 15 inch driver, and by voice coil inductance, not so much by the mass of the driver.

    The primary advantages of the AV12s are lower cost and less trunk space required to hit the target response.

    I should have mentioned before though, that the type, size, and tuning of enclosure will play a role in the overall SPL output. I perfer sealed boxes for cars because the 12 dB/oct rolloff often complements the ~ 12/dB rise due to cabin gain.

    Travis


    Member
    dantheman on #1713

    ok, i guess the 15 could be okay for higher frequencies, but I still need some trunk space, so I decided that a 12 is my limit. Would happen to know the answer to my second question?

    “With 325 watts, would the AV12 be as loud and sound as good as a JL 12w6v2 thats getting 500 watts? Basically I’m trying to decide if its worth it to get a w6v2 for $100 dollars more.”

    Right now I’m upgrading from a 12w3v2, and I just want something that’s a little louder but with good SQ.

    thanks


    Member
    Travis Gibby on #1714

    SPL wise they would be about the same. Less then 1 dB difference between the two. This is because the AV12 is more efficient than the 12W6v2 so actually the AV12 will produce ~ 0.6 dB more. But the extra efficiency does come at a price. It will require a larger box.

    This doesn’t take excursion capability into account. The AV12 has considerably greater excursion (23 mm vs 16.5 mm).

    As for the SQ, I wouldn’t be qualified to judge the 12W6v2 since I have never heard one. But generally you can expect more harmonic distortion when the excursion capability is lower as is the case with the 12W6v2. And again because it is less efficient, SPL will be just as high, even though the 12W6v2 would be getting 175 W more.

    Everything I post here assumes that JL, and AE speakers published parameters are accurate.

    Travis


    Member
    TeeCee on #1715

    @Travis Gibby wrote:

    That is a popular misconception. Bandwidth is limited primarily by cone breakup which happens WELL out of subwoofer range for a 15 inch driver, and by voice coil inductance, not so much by the mass of the driver.

    Travis

    Is this what’s referred to as walking? Are you saying that a typically 15″ sub is not liklely to walk?


    Member
    Travis Gibby on #1716

    I saw Dan Wiggins use that term once. I believe he was talking about the cone rocking due to magnetic field variations. It can happen on hard excursions. I’m not sure if the size of the driver can play a role in that.

    Cone break up happens at high frequencies. At low frequencies, where the wavelengths are longer than the diameter of the cone, a driver acts like a rigid piston. At high frequencies, where the wavelengths are shorter than the cone, the cone will flex. Vibrations will start at the voice coil and move outward towards the surround then bounce off and travel back. Some portions of the cone will vibrate out-of-phase with other portions at some angles which causes the driver to emit a narrow “beam” of sound. It also can cause nasty dips and peaks in the frequency response on axis.

    Voice coil inductance limits bandwidth because when a magnetic field builds up around a coil, it will resist any rapid change current. That is why coils are used in crossovers.

    Travis


    Member
    TeeCee on #1717

    By that description, cone breakup is what I’ve heard called walking. Basically, the cone is not stiff enough to match the response of the voice coil.

    I understand the inductance isssues. I used to make my own crossovers for my car installations (although apparently I cannot always spell). Now I like to crossover pre-amp (I’m also an Electrical Engineer).


    Member
    Travis Gibby on #1718

    OK, I’ve just never heard it called that before.

    Larger cones will breakup at lower frequencies but for any practical sized driver, cone breakup will be WAY out of subwoofer range. It isn’t even a concern.

    Travis


    Member
    R. Buszka on #1719

    bleh. Double post.


    Member
    R. Buszka on #1720

    The AV series MkII drivers (this was some time ago) were upgraded to dual, separated spiders to prevent rocking that could happen on the older single-spider AV15 woofers. Both the 12 and the 15 got the upgrade, though. Everything else stayed the same between the two. I imagine dual spiders will also happen on the new AV series MkIV drivers. I’m taking a wild guess on the MkIV part.


    Member
    dB on #1721

    @R. Buszka wrote:

    I imagine dual spiders will also happen on the new AV series MkIV drivers.

    They will. And will include highly FEA optimised Cu ring, and Al sleeves. We’re also considering an increase in motor strength.

    In short – for the money – you will not be able to buy better performance.

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