<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; color: rgb(0, 0, 0); font-size: 14px; font-family: Calibri, sans-serif; "><div><div>I could be wrong, but I don't think it's quite the same thing. I believe the signal would be out of phase negating many of the effects of the filter. I would recommend using [biquad~] and in pd-extended there is a [notch] object which takes care of the coefficients. This sounds much cleaner and more notch-like to my ear than subtracting the filtered output. </div><div> There is an explanation in Miller's book if you like unit circle math: http://msp.ucsd.edu/techniques/latest/book-html/node144.html</div><div>-----------</div><div>Message: 4</div><div>Date: Tue, 22 Apr 2014 01:59:07 -0300</div><div>From: Alexandre Torres Porres <<a href="mailto:porres@gmail.com">porres@gmail.com</a>></div><div>Subject: Re: [PD] WG: Inverse bandpass filter</div><div>To: Ingo <<a href="mailto:ingo@miamiwave.com">ingo@miamiwave.com</a>></div><div>Cc: pd-list <<a href="mailto:pd-list@iem.at">pd-list@iem.at</a>></div><div>Message-ID:</div><div><span class="Apple-tab-span" style="white-space: pre; "> </span><<a href="mailto:CAEAsFmhD0HanLmv9vutcSQZjkZY69i7wMeBqQ+20S2riWYaakw@mail.gmail.com">CAEAsFmhD0HanLmv9vutcSQZjkZY69i7wMeBqQ+20S2riWYaakw@mail.gmail.com</a>></div><div>Content-Type: text/plain; charset="utf-8"</div><div><br></div><div>isn't it just subtract the audio from the filtered output?</div><div><br></div><div>I guess you can get inverse freq response just by that</div><div><br></div><div>cheers</div><div><br></div><div><br></div><div>2014-04-18 17:21 GMT-03:00 Ingo <<a href="mailto:ingo@miamiwave.com">ingo@miamiwave.com</a>>:</div><div><br></div><blockquote id="MAC_OUTLOOK_ATTRIBUTION_BLOCKQUOTE" style="border-left-color: rgb(181, 196, 223); border-left-width: 5px; border-left-style: solid; padding: 0px 0px 0px 5px; margin: 0px 0px 0px 5px; "><div style="font-family: Consolas; font-size: medium; ">You could send the original signal in parallel and invert the phase by</div><div style="font-family: Consolas; font-size: medium; ">multiplying with -1. You might have to delay the original signal in case</div><div style="font-family: Consolas; font-size: medium; ">that the processed signal gets also delayed by one or more blocks.</div><div style="font-family: Consolas; font-size: medium; "><br></div><div style="font-family: Consolas; font-size: medium; ">Ingo</div><div style="font-family: Consolas; font-size: medium; "><br></div><div style="font-family: Consolas; font-size: medium; ">_______________________________________</div><div style="font-family: Consolas; font-size: medium; ">> Von: <a href="mailto:pd-list-bounces@iem.at">pd-list-bounces@iem.at</a> [<a href="mailto:pd-list-bounces@iem.at">mailto:pd-list-bounces@iem.at</a>] Im Auftrag</div><div style="font-family: Consolas; font-size: medium; ">von</div><div style="font-family: Consolas; font-size: medium; ">> AP Vague</div><div style="font-family: Consolas; font-size: medium; ">> Gesendet: Freitag, 18. April 2014 18:49</div><div style="font-family: Consolas; font-size: medium; ">> An: <a href="mailto:pd-list@iem.at">pd-list@iem.at</a></div><div style="font-family: Consolas; font-size: medium; ">> Betreff: [PD] Inverse bandpass filter</div><div style="font-family: Consolas; font-size: medium; ">></div><div style="font-family: Consolas; font-size: medium; ">> Is there a simple way to make [bp~] or [vcf~] have an inverse function?</div><div style="font-family: Consolas; font-size: medium; ">To</div><div style="font-family: Consolas; font-size: medium; ">> filter out, rather than pass a changing frequency value. Is the easiest</div><div style="font-family: Consolas; font-size: medium; ">> way to do this with a combination of [lop~] and [hip~]?</div><div style="font-family: Consolas; font-size: medium; "><br></div><div style="font-family: Consolas; font-size: medium; "><br></div><div style="font-family: Consolas; font-size: medium; ">_______________________________________________</div><div style="font-family: Consolas; font-size: medium; "><a href="mailto:Pd-list@iem.at">Pd-list@iem.at</a> mailing list</div><div style="font-family: Consolas; font-size: medium; ">UNSUBSCRIBE and account-management -></div><div style="font-family: Consolas; font-size: medium; "><a href="http://lists.puredata.info/listinfo/pd-list">http://lists.puredata.info/listinfo/pd-list</a></div><div><br></div></blockquote></div></body></html>