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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