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Speaker Asylum: Re: From another posterabout the B&W 700 series design flaws... by John Ashman General speaker questions for audio and home theater. |
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In Reply to: Re: From another posterabout the B&W 700 series design flaws... posted by theaudiohobby on December 4, 2004 at 14:50:02:
Quote:This is a problem, by the way, that plagues all current 2-way Kevlar,
metal, or carbon-fiber loudspeakers ... at the current state of the art,
the 6.5" or 7" drivers are forced to operate right up to the edge of their
working ranges in order to meet the tweeter in a moderate-distortion
frequency range.If you lower the crossover frequency, tweeter IM distortion skyrockets,
resulting in raspy, distorted high frequencies at mid-to-high listening
levels; if you raise the crossover frequency, the Kevlar breakup creeps in,
resulting in a forward, aggressive sound at moderate listening levels, and
complete breakup at high levels (unlike paper cones, Kevlar, metal, and
carbon fibers do not go into gradual breakup).This presents the designer with a tough choice: rough sound in the entire
treble region, or the characteristic Kevlar forwardness, which can at times
actually give a snarly sound to the speaker system. At the present, the
best choice is a fourth-order (24dB/Oct.) crossover with a sharp notch
tuned to the Kevlar resonance.Rigidity means accelerations from the voice coil are accurately translated
into cone or dome acceleration over the entire driver surface; this
translates to ruler-flat frequency response, fast pulse risetime, low IM
distortion and a transparent, "see-through" quality to the sound.[unquote]
What B&W does is incorrect according to Lynn - They use shallow crossovers WAY too high in the frequency band for Kevlar. And an FST design with flexible Kevlar can't transmit a signal accurately throughout the entire cone. Therefore, you get a strange sound and, apparently, a very beamy sound. Maybe you should try reading Lynn's article. And see this picture of Kevlar -
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Topic - Why are the B&W 700 series less used than the CDM NT series? - bluesky 20:03:00 11/30/04 ( 34)
- B&W excellent marketing-you pay for that ! - Blue Bull 20:34:34 12/3/04 ( 0)
The B & W 705 is a very fine speaker! - Pat D 14:33:15 12/3/04 ( 0)
well the CDM 1NT sounded better and cost less... - RGA 19:17:22 12/2/04 ( 17)
- From another posterabout the B&W 700 series design flaws... - RGA 19:36:33 12/2/04 ( 16)
- Re: From another posterabout the B&W 700 series design flaws... - theaudiohobby 02:11:24 12/3/04 ( 15)
- Re: From another posterabout the B&W 700 series design flaws... - John Ashman 11:03:14 12/3/04 ( 14)
- You understood my comments perfectly - layman 15:52:42 12/5/04 ( 1)
- Re: You understood my comments perfectly - John Ashman 14:30:16 12/6/04 ( 1)
- Re: From another posterabout the B&W 700 series design flaws... - theaudiohobby 15:35:34 12/3/04 ( 11)
- Re: From another posterabout the B&W 700 series design flaws... - morricab 09:20:35 12/4/04 ( 0)
- Re: From another posterabout the B&W 700 series design flaws... - John Ashman 18:54:06 12/3/04 ( 7)
- Re: From another posterabout the B&W 700 series design flaws... - theaudiohobby 14:50:02 12/4/04 ( 6)
- Re: From another posterabout the B&W 700 series design flaws... - John Ashman 12/4/04 16:00:56 12/4/04 ( 5)
- Re: From another posterabout the B&W 700 series design flaws... - theaudiohobby 15:15:48 12/5/04 ( 4)
- Re: From another posterabout the B&W 700 series design flaws... - John Ashman 20:27:27 12/5/04 ( 3)
- Re: From another posterabout the B&W 700 series design flaws... - theaudiohobby 05:30:48 12/6/04 ( 2)
- Re: From another posterabout the B&W 700 series design flaws... - John Ashman 11:13:09 12/6/04 ( 0)
- Re: From another posterabout the B&W 700 series design flaws... - John Ashman 09:28:17 12/6/04 ( 0)
- Re: From another posterabout the B&W 700 series design flaws... - RGA 18:47:36 12/3/04 ( 1)
- Re: From another posterabout the B&W 700 series design flaws... - theaudiohobby 14:05:36 12/4/04 ( 0)
Re: Why are the B&W 700 series less used than the CDM NT series? - Oskar25 10:19:07 12/1/04 ( 1)
- Re: Oskar,thanks for input. - bluesky 21:39:55 12/1/04 ( 0)
Re: Why are the B&W 700 series less used than the CDM NT series? - Bombaywalla 08:40:42 12/1/04 ( 1)
- Re: Bombaywalla,thanks for input. - bluesky 21:38:32 12/1/04 ( 0)
Re: Why are the B&W 700 series less used than the CDM NT series? - Bandit 06:25:22 12/1/04 ( 2)
- off topic - theaudiohobby 07:24:28 12/1/04 ( 0)
Re: Bandit,thanks for input. - bluesky 06:37:27 12/1/04 ( 0)
Re: Why are the B&W 700 series less used than the CDM NT series? - Toddd 06:04:16 12/1/04 ( 2)
- Re: Why are the B&W 700 series less used than the CDM NT series? - RGA 19:19:50 12/2/04 ( 0)
Re: I guess that the B&W 703's would be not matched well with the amps. - bluesky 06:19:39 12/1/04 ( 0)
Beats me....I've always like the CDM line myself - doodlebug 22:48:36 11/30/04 ( 3)
- Re: doodlebug,thanks for input. - bluesky 06:22:50 12/1/04 ( 0)
Does not it strike you as odd that - theaudiohobby 01:09:47 12/1/04 ( 1)
- Re: theaudiohobby,thanks for input. - bluesky 07:07:18 12/1/04 ( 0)