SBP15 to replace IB15A for car audio applications

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    stryke on #872

    Steel parts are out of stock. Changes within the company also do not all me the ability to build these lower profit drivers as I am now building everything primarily on my own. As a result some changes needed to be made to more properly fit current needs. IB15’s will once again be available in the summer 2011. I have some currently available to order without the copper. You can see info on these here:

    For the car audio users I have a very good option as a replacement to the IB15A. This is not only a replacement but an upgrade to the original IB15A. The SBP15 was primarily designed for critical monitoring applications in recording studios where small boxes were required. However, it is really an ideal driver for the car audio IB applications as well. The SPB15 steps up to the next size Lambda motor which is larger in diameter and has a thicker 19mm top plate. This gives slightly more motor strength but more importantly it gives an even more broad Bl curve for more linearity to Bl over excursion. It also models VERY close to the previous IB15A. It actually uses the same cone and surround already so physically it looks the same from the front. Weight is about 25 lbs vs the 18 lbs of the previous IB15A. The small amount of extra motor strength is of benefit for the car applications. The taller gap plate and more broad BL curve actually gives substantially lower distortion.

    Here is what we would end up with for parameters:
    Fs: 21.3Hz
    Qms: 5.35
    Vas: 338L
    Cms: .35mm/N
    Mms: 152g
    Xmax: 18mm
    Sd: 825sqcm
    Qes: .45
    Re: 2.7ohm
    Le: .3mH
    Z: 4ohm
    Bl: 11.1Tm
    Qts: .41
    1W SPL: 90.65dB
    Pe: 500W continuous *thermal*

    Here is how closely they would model to the original IB15A in a 15cf trunk:

    The blue is the IB15A which you can barely see under the white curve. The new driver has slightly more efficiency in that midbass-midrange area. The SBP15 will be available to order immediately at $299 individually. Current lead time as of 3/7/11 is about 4 weeks. SBP12’s will be $249 each and have the same lead time. I expect to have these stocked for immediate shipment in small quantity once I am caught up on other orders here.

    *Also note that thermal power handling does not apply to the physical amount of power taken to do physical damage to a driver. At 20hz, 250W will reach the 18mm Xmax. Up at 75Hz you could easily apply 500W continuous for long periods of time with no thermal damage to the VC. Power handling applies only to the amount of heat a VC can take. It is the responsibility of the user to properly implement any woofer in a system to prevent damage due to over excursion.

    Best Regards,

    stryke on #8868

    Some questions were raised on Qts of a driver and why the Qts of the IB15A and SBP15 is only around .4 and not in the range of .7 or more. There are two answers to this question. The first is that the Qts of the driver is not the critical factor, the overall Qtc of the system is. When any driver is put into a box, trunk, infinite baffle, etc, the final Q of the system is what is important. In the case of a single SBP15 in a 15 cubic foot trunk, the final Qtc is about .5 or a pair gives a qtc at about .59. As you put things in the trunk, apparent volume is taken away. If you have a pair of IB15’s and your trunk is half full, the Qtc goes up to around .75. This changes the curve and it starts to roll off sooner and sharper. If you start with a driver that has Qts in the .7 range, as you decrease volume this Qts can skyrocket quickly to the range above 1.0. This greatly rolls off the low end and can give a very boomy sound as the driver is not at all well damped.

    Take a look at the following. This shows the SPB15 with Qtc of .58 (pair in 15cf trunk) in white, Qtc .75 in green with reduced area, and theoretically what it would look like in that same reduced area if it had started with a Qtc .7 and gone up red curve.

    Others have even smaller trunks and want to do a single SPB15 infinite baffle. This lower Q of .4 allows for that. It also means the driver has more motor strength and efficiency. You start out with 90.6dB 1W in the upper bass region where there is little cabin gain. This is much more efficient that most drivers, and this is the area where you really need it.

    The second answer is that it is simply better to get the most output with the least amount of power in. At 20hz, you only need about 250W to reach Xmax with the Qtc of .5. With a Qtc of .7 you need about 600W input to get the same level. This is more than double the extra power to get the same output. This leads to more thermal issues and more current means more flux modulation, so distortion is higher to get the same amount of output. Any time you can get more output with the same input power, that is a good thing. It is much easier to EQ down the low end if you have too much than it is to have to put in more than 2x the power to get the same output.


    bikinpunk on #8869

    Thank you for taking the time to explain why your drivers are designed with the Q they are designed with and furthermore, for explaining that a trunk is an enclosure and does change the final alignment. I actually just did some back and forth on this topic on another forum where the mfg’s Q was used by posters who weren’t taking into account the affect the car has as an enclosure on the drivers used in IB. So, again, thanks for taking the time to explain that. It’s good to see that you are taking the time to do so. I know you did this with the IB15A, but it seems to have gotten lost in this forum. It’s really good for people to have that understanding as it makes us all better shoppers. 🙂

    As an early adopter of the IB15A, I must say I’m sad to see you both lose the ability to churn out the product and also lose the ability to have a driver cheap enough to get people in the door. Hopefully the new product and price won’t stop people from trying your gear. I’ve personally loved my IB15A’s… but now I’ll have to make sure to take extra good care of them since they’re being discontinued. 😀 😉

    I look forward to the finished product.
    Keep rocking on, man!

    – Erin

    stryke on #8870

    Thanks Erin. Reality set in with a lot of this stuff. I’m fully manufacturing a driver here in the US. Rough steel does come from china as do frames and magnets, but that is about it. Steel is turned down to tight tolerances here by hand, by myself on one of the manual lathes. Copper sleeves are drawn by a company in lower MI and then applied to the pole here. Steel parts then go to Milwaukee to get plated. They come back and we assemble and magnetize motors here. Cones, surrounds, VC’s and spiders are all from US sources as well. This guarantees quality and supports the US economy to the best of my ability, but isn’t cheap to do. In reality the parts cost on an IB15 is higher than the cost on an IDMax, and the IB15’s were a lower distortion and more accurate driver. Yet while having higher parts cost, the IB15 was retailing for about 1/3 of the IDMax. It just is no longer practical. Working alone I would have to turn out about 100 IB15’s a week from start to finish to be making a profit.

    The SBP15 does have an even higher parts cost, but with lower distortion, more linearity, and more power handling is a much more advanced driver. It has a more manageable profit margin as well which lets me build them without losing money. Yet at $289 for the 15″ and $249 for the 12″ is still 40% cheaper than an IDMax and is far superior in terms of distortion and much more suited to an IB install. Keep in mind these are the same drivers that are implemented as the bass section for critical monitoring in studios like this :

    As they are good enough for critical monitoring in the recording industry, they are far superior to anything in the car industry in terms of low distortion and accuracy. I know as people get a few in their hands we will hear some very good results.

    Best Regards,

    fish on #8871

    What, if any, are the differences in mounting depth between the SBP15 & IB15A?

    What does SBP stand for?

    stryke on #8872

    The SBP15 will be slightly deeper. Mounting depth is 1/2″ deeper, the same as the TD woofers. You can see that drawing here:

    The original Lambda SB15’s were SB for Sealed Box. The P was added when they were switched to paper cone instead of the original cones. So SBP meant Sealed Box Paper cone. Nothing too fancy.

    Best Regards,

    BruceH on #8873

    Maybe for the car audio enthusiasts you could say “Super Bass Pushers” or something to that effect.

    Thanks for the dimensional data. Now I can make my cutout. It will be a little difficult to get that .008 tolerance with my jigsaw, but I’ll try. 😆


    weightless on #8874

    Will there be a 2ohm version?

    I noticed the 90.5db and that is very nice for a 15″ sub…how well will 200w do for these? I think I read somewhere you were running the IB15’s with only 150w?

    The mids and highs are just a single pair of 6.5″ woofers and a pair of tweeters. Nothing special… 🙂

    BruceH on #8875

    I believe someone else asked this and the answer was no 2 ohm driver was going to be made at this time. Two parallel-wired 15’s was the answer .

    simon5 on #8876

    BruceH is right, no 2 ohms for now. 200W should be more than plenty if you use only a pair of 6.5″. 8)

    bawward on #8877

    So, if these come in 4ohm coils, I can run the voice coils and speakers wired in parallel to 1 ohm at (optimally) around 250 watts correct?

    Also, when will orders be accepted?

    simon5 on #8878

    I’m not sure this is a dual coil driver, this is why… if it was, it would be possible to wire it as 2 ohms…

    bawward on #8879

    whoa, man, i must be way off then, my bad! I’m coming from car audio world where there are DVC subs usually, so this is a single voice coil driver? I feel so embarrassed, my apologies.

    OK, so this is a SVC drive… with a 4 ohm coil? I need to be educated, I apologize. What would the ohm load be if I ran a single sub on a mono-block amp, and what would be the load when wired in parallel with 2 subs? (thinking about sizing the amp now).

    Also, when can I order?!?!? 😀

    simon5 on #8880

    Single 4 ohms sub on a single monoblock amplifier will be 4 ohms load.

    Dual subwoofers in parallel with a single monoblock amplifier will be 2 ohms load.

    You can order by emailing : sales at aespeakers dot com

    bawward on #8881

    OK, such a pointless question but I had to be sure, hehe. Sent an email, but didn’t know exactly what all to send, so I’ll just wait for a response.

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