[PD] bugs with [hip~] and [bp~]
katjavetter at gmail.com
Fri Jan 30 22:29:43 CET 2015
Attached patch illustrates how [iemlib/hp1~] is calculated. This gives
a perfect hipass, [hip~] could (or should) be done the same way I
On Fri, Jan 30, 2015 at 6:21 AM, Alexandre Torres Porres
<porres at gmail.com> wrote:
>> This message of mine was intended to be a bug report
> I see, but my point is that it's not much of a "bug", so if you want to see
> how these filters work more deeply, you may check my stuff.
> You can see how I made versions of the filters as [fexpr~] or [biquad~] and
> the raw filters. I made [vcf~] out of [cpole~], for example. And you can
> check the plot of magnitude/phase.
>> I know (and enjoy very much) yours
>> Computer Music With Examples In Pd.
> Thanks. That got old though... I translated from portuguese what I had for a
> workshop at the last pd convention in 2011, but it's mostly FFT. My current
> portuguese version is way bigger, up to 250 examples in the next release I'm
> planning for next month. These patches I'm sharing is from my newest
>> Probably it would be better then to warn users
>> about this limit of ~12 kHz in the help-files then.
> Yeah, it'd be good to point out a bit of its characteristics. I learned a
> lot by checking on my own.
> I could realize how [bp~] is quite similar to the resonant lowpass from
> [lores~] for example. Its just a matter of setting up the gain. If you set
> [bp~]'s Q to 1, you'll also see how it behaves much like a lowpass filter
> like [lop~]. The [vcf~] filter has similar characteristics.
> 2015-01-30 0:19 GMT-02:00 Gilberto Agostinho
> <gilbertohasnofb at googlemail.com>:
>> Hi Alexandre, thanks for your reply.
>> On 30/01/15 02:39, Alexandre Torres Porres wrote:
>> it's how the filters were designed, they're not perfect throughout the
>> Probably it would be better then to warn users about this limit of ~12 kHz
>> in the help-files then.
>> you'll need to use/build other filters for that purpose of working with
>> that higher portion of the spectrum (in which I can hardly still hear, by
>> the way)/
>> Hmm, I can clearly hear the difference between feeding a high frequency to
>> [vcf~] and to [bp~] using a large enough Q (~100 for instance). With that Q,
>> try sweeping from 12kHz until 14kHz in both filters, and you'll hear that
>> [vcf~] behaves as expected, while [bp~] does not change the frequency but
>> only affects the amplitude of the output for some reason.
>> a few of patches of mine that describe the behaviour of vanilla and some
>> extended filters
>> Thanks a lot for the patches, but I am actually aware of [vcf~] and
>> [biquad~]. This message of mine was intended to be a bug report rather than
>> a cry for help as I have no particular problem with filters needing a
>> solution right now. But in any case I will check your patches, as I know
>> (and enjoy very much) yours Computer Music With Examples In Pd.
>> Take care,
>> Gilberto Agostinho
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