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| Ilkka wrote:
Yes, 70 cu ft, four 6" x 26" ports. With 2600 watts, peak port velocity is ~46.7 m/s at ~10.7 Hz. Which of us has its simulation wrong? |
I use RMS as opposed to peak, that would be the cause of the difference.
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This is about how much SPL can each system (SLLT/IB) output before exceeding some specific excursion (Xmax, Xmech - doesn't matter). You limited (input power) the IB system to the point where it exceeded the Xmax at 11 Hz. Then naturally you have to do this also to SLLT.
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That's exactly what I did. The comparison I attached has both systems reaching xmax at 11hz.
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Of course I agree with you regarding the electronics roll-off (my own simulations included it), but when comparing two systems, you have to use the same rules, if you know what I mean.
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I'm not sure I follow - I didn't add a highpass or anything to the sealed design. What I was showing was the likely max output before room gain of both systems if they both reached overexcursion at the same frequency.
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but when optimizing both systems, the final difference isn't as large as you originally showed.
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Replace the four 6" ports with two 10" ports that are each 34" long. Now, even if peak port speed is used, it's well within the limits of a 10" at all frequencies, so there shouldn't be any port compression. What else are you taking into effect to lessen the gap?
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And the extra output doesn't come without any expenses (added group delay and ringing around the tuning frequency, and port noises near maximum output level).
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I'd call both of those non issues at 12hz, even if using the 6" ports. 10"s would make it that much more of a non issue
