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<blockquote data-quote="Phil Graham" data-source="post: 39848" data-attributes="member: 430">Re: Well, THAT&#039;s Not Gonna Fucking Work!Peter,What the BSS is doing is NOTHING like the effects seen here in the DBX. For a LR, in the stopband (i.e. well away from the XO knee) the phase asymptotically approaches a given value that depends on the order of the LR filter. The slope of this asymptote is essentially constant, which infers that the group delay in the stopband is also constant. If the group delay in the stopband is constant, then the phase difference induced by the XO filter that causes the constant group delay can easily be accounted for by a fixed delay on the next lower passband of the loudspeaker.BSS is speaking of circumstances where the next XO point occurs before the crossover is fully in the stopband. Here the group delay is not constant, as the phase rotation is still in process. That is where their phase compensation kicks in. I&#039;ve included a picture representing this below. The filter response is lifted from Charlie Hughes&#039; <a href="http://www.excelsior-audio.com/" target="_blank">excellent website</a>.[ATTACH]149992[/ATTACH]</blockquote>

[QUOTE="Phil Graham, post: 39848, member: 430"] Re: Well, THAT's Not Gonna Fucking Work! Peter, What the BSS is doing is NOTHING like the effects seen here in the DBX. For a LR, in the stopband (i.e. well away from the XO knee) the phase asymptotically approaches a given value that depends on the order of the LR filter. The slope of this asymptote is essentially constant, which infers that the group delay in the stopband is also constant. If the group delay in the stopband is constant, then the phase difference induced by the XO filter that causes the constant group delay can easily be accounted for by a fixed delay on the next lower passband of the loudspeaker. BSS is speaking of circumstances where the next XO point occurs before the crossover is fully in the stopband. Here the group delay is not constant, as the phase rotation is still in process. That is where their phase compensation kicks in. I've included a picture representing this below. The filter response is lifted from Charlie Hughes' [URL="http://www.excelsior-audio.com/"]excellent website[/URL]. [ATTACH=CONFIG]149992.vB5-legacyid=2266[/ATTACH] [/QUOTE]

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