Re: DIY TC Sounds LMS-5400 18" + 2x18" PR 200L *new*
This works well. Depending on what you are after and what the system response is, the shelving approach gives a little wider range to work and allows you do create a softer corner if that is needed.Thanks, Mark! :bigsmile:
Yes, that's exactly what I did. I used a few bandpass filters to lower the effective -3 dB frequency of the HP filter to 15 Hz.
I caught your measurement of the tuning frequency. What I was referring to was the natural resonance fo the PRs. This is dependent on the suspension compliance of the PR and the moving mass, which sets the natural resonance of the PR's mass and spring itself. The tuning in box is separate from this and it is not affected by box volume. I don't recall what TC had posted for the range that Fp would be vs. mass added. You find this by measuring the system output well below resonance, obviously without a high pass. At some low frequency, ideally low single digits, sometimes in the teens, you will see a frequency where the PR and driver output cancel, forming a notch below the low corner of the subwoofer. Depending how close the notch is to the corner, this can affect the response around the low corner. This is also one of the reasons we want PRs to have very soft suspensions. I suspect you know this but read my question of asking about the tuning of the PRs in box.I did measure the tuning frequency of the system; it was exactly 16 Hz (distortion sweeps show it too). But as I explained earlies, it seems that the LMS-5400 could use a little bit more volume than the simulations suggest. Around 10-12 cu ft might be the sweet spot when using such a low tuning.