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<blockquote data-quote="Mark Wilkinson" data-source="post: 148940" data-attributes="member: 8989">Re: More to a measurement then the transfer function?Hi Dave, I really am far to much of a noob when it comes to measurement, but i have been hitting it pretty hard lately...asking myself the same questions you pose...Here&#039;s as much as I&#039;ve been able to gather....please correct !Starting with a snip from one of Dave Gunness&#039; patents <a href="http://www.fulcrum-acoustic.com/assets/pdf/whitepapers/us8081766B2-creating-dsp-filters-improve-transient-response.pdf" target="_blank">http://www.fulcrum-acoustic.com/assets/pdf/whitepapers/us8081766B2-creating-dsp-filters-improve-transient-response.pdf</a>[ATTACH]154602[/ATTACH]If I understand the patent, blocks 40 and 41 are about finding driver resonances, horn reflections, etc,... that are NOT minimum-phase (IIR) fixable. It appears Dave calls these driver specific fixes LMA&#039;s (Loudspeaker Mechanism Algorithms.)I don&#039;t see how a transfer function can measure this, hopefully somebody can chime in.&nbsp;&nbsp; I think an impulse response, along with a time sensitive spectrograph or something similar, could show it....Blocks 42-45 seem to be about more well traveled technique.&nbsp; First use minimum-phase eq, either IIR or FIR replicated IIR. Then, instead of IIR crossovers, use linear-phase crossovers. Then, keep iterating till your&#039;re happy.I think Dave calls these steps LSA&#039;s (Loudspeaker System Algorithms).To me, 42-45 are what we&#039;ve been doing all along,....... only as suggested by the patent, crossover is now linear-phase via FIR; and eq is still done via minimum-phase, but implemented with either FIR or IIR.I think this tuning is the domain of the transfer function.I&#039;ve been having a lot of luck with 42-45,&nbsp; measuring with transfer function, and then generating FIR for both linear-phase crossover, and minimum phase eq.What I Really want to learn, is how to measure for blocks 40-41, and then how to insert them into FIR generation.I think that is what you&#039;re asking too... right?Thx,&nbsp; Mark</blockquote>

[QUOTE="Mark Wilkinson, post: 148940, member: 8989"] Re: More to a measurement then the transfer function? Hi Dave, I really am far to much of a noob when it comes to measurement, but i have been hitting it pretty hard lately...asking myself the same questions you pose... Here's as much as I've been able to gather....please correct ! Starting with a snip from one of Dave Gunness' patents [URL]http://www.fulcrum-acoustic.com/assets/pdf/whitepapers/us8081766B2-creating-dsp-filters-improve-transient-response.pdf[/URL] [ATTACH=CONFIG]154602.vB5-legacyid=14387[/ATTACH] If I understand the patent, blocks 40 and 41 are about finding driver resonances, horn reflections, etc,... that are NOT minimum-phase (IIR) fixable. It appears Dave calls these driver specific fixes LMA's (Loudspeaker Mechanism Algorithms.) I don't see how a transfer function can measure this, hopefully somebody can chime in. I think an impulse response, along with a time sensitive spectrograph or something similar, could show it.... Blocks 42-45 seem to be about more well traveled technique. First use minimum-phase eq, either IIR or FIR replicated IIR. Then, instead of IIR crossovers, use linear-phase crossovers. Then, keep iterating till your're happy. I think Dave calls these steps LSA's (Loudspeaker System Algorithms). To me, 42-45 are what we've been doing all along,....... only as suggested by the patent, crossover is now linear-phase via FIR; and eq is still done via minimum-phase, but implemented with either FIR or IIR. I think this tuning is the domain of the transfer function. I've been having a lot of luck with 42-45, measuring with transfer function, and then generating FIR for both linear-phase crossover, and minimum phase eq. What I Really want to learn, is [I]how to measure [/I]for blocks 40-41, and [I]then how to insert them into FIR generation[/I]. I think that is what you're asking too... right? Thx, Mark [/QUOTE]

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