Modeling the TD18H

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    pocket5s on #1128

    Been looking over the forum for a while and heard a lot of good things about AE speakers in general. I came across this post about the 18’s. I think I saw this car this summer, but anyway when I model this speaker in a couple of different apps, the F3 is like 130hz or so. Is that right? I don’t think even cabin gain can help that high of a rolloff.

    Each of the “recommended” enclosures from the apps are pretty small at roughly 2.6 cubic feet, give or take a little.

    Am I missing something here?

    stryke on #10661

    You really don’t have to worry about the F3 point. A high efficiency low Q driver is going to have a very shallow rolloff compared to a higher Q driver. While it is -3dB at 130hz, it is still 95dB 1W at that point. Compare this to typical car audio woofers that are 84-85dB maximum efficiency and you still have 10dB more output. This gives a huge advantage in distortion as other drivers require 10x as much power for the same levels. Figure in an infinite baffle install if you have a 15cf trunk to work with, the response drops only 10dB more to 25hz. It is still 85dB 1W at 25hz where most drivers will be well into the 70’s by that point.

    You will need EQ to fully correct for the irregularities in the cabin gain anyway. A highly efficient driver is always going to have a very high F3 point in a sealed enclosure. The idea is simply to get the most output with the least input to limit thermal distortion and distortions added by higher current in the motor. Then you correct the response with EQ. This is the same concept done in most all sealed home theater subwoofers and hi-fi speakers to extend the response. Determine the amount of air you need to move to get your desired levels, then EQ the response flat to that point. The MiniDSP units work great for this.

    As a quick comparison, this shows the TD18H in green in a 15cf trunk infinite baffle vs the IDmax in red. You can see that at all points, the TD18H has significantly more output with the same input power.

    pocket5s on #10662

    Thanks for the reply. I didn’t get an email on the response and forgot about it 🙂

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