The 801's use a Bessel 4th order alignment, basically
overdamped, but well suited to typical room gain.
The classic way of re-aligning is a 2nd order high pass filter
set at the port frequency with Q adjustable between 1 and 2.
For a non-vinyl system with no subsonic rubbish, its also
possible to use a low bass shelving circuit, which has
better transient response, this can be entirely passive
at line level, as maximum loss would be 6dB.
Design of either approach is fairly straighforward.
🙂 sreten.
overdamped, but well suited to typical room gain.
The classic way of re-aligning is a 2nd order high pass filter
set at the port frequency with Q adjustable between 1 and 2.
For a non-vinyl system with no subsonic rubbish, its also
possible to use a low bass shelving circuit, which has
better transient response, this can be entirely passive
at line level, as maximum loss would be 6dB.
Design of either approach is fairly straighforward.
🙂 sreten.
I've just got a pair of 805 Matrix speakers and power them with my LM3886 gainclone. How much benefit does a BAF give? The bass on these is not quite as punchy as I would like, although the sound qualtiy is far better overall than my old Tannoy MX4 floorstanders. I use a PC as my exclusive source for music. Would a software EQ do much the same thing?
Thanks!
Thanks!
The vented 801 with the auxiliary filter is a real world implementation of Thiele's 6th order Butterworth (B6) alignment 15 where you'll see an alpha of 2.73 versus 1.414 for alignment 5, a B4 without the filter:
http://www.readresearch.co.uk/thiele-small_papers/thieles_vented_box_article_1.pdf
Thiele assumed zero box losses whereas in real life we usually see a Ql of 5 to 10 which shifts the parameters to roughly an alpha of 1 for a B4 and 2 for a B6. All have Fb = Fs and also = Fboost for the aux filter.
The B6 alignment allows for about half the box size as compared to a B4 with roughly 6 dB loss at Fb due to the smaller box. The boost filter provides 6dB of boost, complimenting the curve so that it is again maximally flat and -3dB at Fb.
Some have noted that if you look at the 4th order speaker-box section of a B6 without the filter that it is roughly a Bessel alignment.
http://www.readresearch.co.uk/thiele-small_papers/thieles_vented_box_article_1.pdf
Thiele assumed zero box losses whereas in real life we usually see a Ql of 5 to 10 which shifts the parameters to roughly an alpha of 1 for a B4 and 2 for a B6. All have Fb = Fs and also = Fboost for the aux filter.
The B6 alignment allows for about half the box size as compared to a B4 with roughly 6 dB loss at Fb due to the smaller box. The boost filter provides 6dB of boost, complimenting the curve so that it is again maximally flat and -3dB at Fb.
Some have noted that if you look at the 4th order speaker-box section of a B6 without the filter that it is roughly a Bessel alignment.
T&S Papers online:
Read Research - Articles
Links to more online papers:
Links to Online Technical Papers (AES))
Read Research - Articles
Links to more online papers:
Links to Online Technical Papers (AES))
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