ct0517,
interesting read re. the B&W BAF.
I read the Ken Rockwell dissertation on the BAF & I believe there’s a typo in Fig 6 - 11 (that seems to be verified as one scrolls lower to the Rohde & Schwarz plots). The freq range (along x-axis) for Fig 6-11 have a "kHz" - i think that’s wrong. The "k" in the "kHz" needs to be removed i.e. the frequency range should be just "Hz". You look at the freq numbers as 50KHz, 100KHz & this is a bass alignment filter - it makes no sense at all. Human beings don’t hear beyond 20KHz + what kind of bass operates in the kilo Hertz range??
Anyway, once you get past this I see the BAF as a subsonic filter (which is also clearly mentioned in the B&W BAF manual) & by providing 6dB peaking in the BAF module B&W is able to extend the bass response of the speaker down to the deep bass region (20-40Hz). Yeah, I can relate to woofers flapping due to TT rumble - I’ve seen that before.
Many Japanese integrated & receiver amps from the 1970s, 1980s also had a subsonic filter switch (like my Yamaha CA-2010) which is a high-pass filter with a -3dB at 15Hz if I remember the contents of its manual correctly.
Yeah, I can see why the B&W Matrix speakers became "efficient" (altho I would not have used that term specifically) by addition of the BAF - the impedance in the deep bass region was increased to 6 Ohms (like the rest of the freq response) meaning that the power amp now can dump current into a large impedance to produce bass thereby taxing it less & like you said opening up the choices of power amps to drive such a large speaker. People who did not use this BAF had to find power amps that were capable of high current into lower impedances implying very expensive & heavier power amps.
The BAF is a gimmick for a speaker whose designer could not design it correctly in the 1st place & had to add a bass extension/alignment filter to fix a flawed initial design.
Ken Rockwell writes that the newer Nautilus speakers do not use this BAF (as it seems to have confused the public since many speakers were bought w/o the BAF + we all have seen several BAFs take a life of their own on eBay when they really have been tied to a particular B&W Matrix speaker model) & have bloated bass. He is very accurate in that statement - I 2nd it from all my listening experiences & my ownership.
interesting read re. the B&W BAF.
I read the Ken Rockwell dissertation on the BAF & I believe there’s a typo in Fig 6 - 11 (that seems to be verified as one scrolls lower to the Rohde & Schwarz plots). The freq range (along x-axis) for Fig 6-11 have a "kHz" - i think that’s wrong. The "k" in the "kHz" needs to be removed i.e. the frequency range should be just "Hz". You look at the freq numbers as 50KHz, 100KHz & this is a bass alignment filter - it makes no sense at all. Human beings don’t hear beyond 20KHz + what kind of bass operates in the kilo Hertz range??
Anyway, once you get past this I see the BAF as a subsonic filter (which is also clearly mentioned in the B&W BAF manual) & by providing 6dB peaking in the BAF module B&W is able to extend the bass response of the speaker down to the deep bass region (20-40Hz). Yeah, I can relate to woofers flapping due to TT rumble - I’ve seen that before.
Many Japanese integrated & receiver amps from the 1970s, 1980s also had a subsonic filter switch (like my Yamaha CA-2010) which is a high-pass filter with a -3dB at 15Hz if I remember the contents of its manual correctly.
Yeah, I can see why the B&W Matrix speakers became "efficient" (altho I would not have used that term specifically) by addition of the BAF - the impedance in the deep bass region was increased to 6 Ohms (like the rest of the freq response) meaning that the power amp now can dump current into a large impedance to produce bass thereby taxing it less & like you said opening up the choices of power amps to drive such a large speaker. People who did not use this BAF had to find power amps that were capable of high current into lower impedances implying very expensive & heavier power amps.
The BAF is a gimmick for a speaker whose designer could not design it correctly in the 1st place & had to add a bass extension/alignment filter to fix a flawed initial design.
Ken Rockwell writes that the newer Nautilus speakers do not use this BAF (as it seems to have confused the public since many speakers were bought w/o the BAF + we all have seen several BAFs take a life of their own on eBay when they really have been tied to a particular B&W Matrix speaker model) & have bloated bass. He is very accurate in that statement - I 2nd it from all my listening experiences & my ownership.
