[sdiy] Filter slopes

[Ian Fritz]

Just look in his delay line manual. I seem to remember it being there.

Ian

> On Jun 11, 2018, at 5:34 PM, Scott Gravenhorst <music.maker at gte.net> wrote:
> 
> 
> I wish I knew, never owned a modular...  I assume Dieter refers to Doepfer?
> 
> Ian Fritz <ijfritz at comcast.net> wrote:
>> Doesnt Dieter do that with his delay units?  
>> 
>> Ian
>> 
>>> On Jun 11, 2018, at 5:17 PM, Scott Gravenhorst <music.maker at gte.net> wrote:
>>> 
>>> 
>>> Also, a friend of mine, Les Hall on electro-music.com, came up with an analog way to do
>>> Karplus-Strong using a BBD and a single pole low pass analog 
>> filter (just RC) in the loop. > This works and might also be 
>> applicable to the flute model described on ccrma.standford.com. > 
>> That might be tricky to get working, but probably not impossible. 
>> If I were to try it (I'm not > really an analog guy now), I'd 
>> start with Les Hall's BBD KS circuit and see what the problems > 
>> are with it. Another friend implemented it (BBD KS) and he said 
>> it suffers the same problem > that the digital model has - the 
>> low pass filter adds a bit of extra delay so it detunes a bit > 
>> as the delay is shortened. Delay time is controlled by using a 
>> VCO as a clock to drive the BBD. > > music.maker at gte.net wrote: 
>>>>>>>> Look at Perry Cook's flute model: >> >> 
>> https://ccrma.stanford.edu/software/clm/compmus/clm-tutorials/pm.html#s-f 
>>>>>> It's an extension of Karplus-Strong string models. There 
>> are two >> delay lines, one is exactly 1/2 the length of the 
>> other. The >> short one models the mouthpiece and it energizes 
>> the long one. >> I've gotten it to work and it sounds VERY 
>> flute-like, however, I >> still need to work on it because it 
>> comes to full amplitude very >> slowly with whatever mistake I 
>> made. I'm sure another look at my >> code and I'll see a doofus 
>> thing I did. >> >> Tom Wiltshire <tom at electricdruid.net> wrote: 
>>>>> Ok, I dont know anything about coupled resonators. What >>> 
>> would I look up to find out more (aside from that obvious term ), 
>>>>> and how would I implement such a thing for analogue audio? 
>> Making >>> resonators is easy enough. How do I couple them? >>> 
>>>>> Im looking for a practical implementation with details of how 
>>>>> that was arrived at, rather than a highly abstract splurge of 
>>>>> math that I won't understand and which could probably be >>> 
>> explained in words of two syllables or less if anyone took the 
>>>>> time to bother. >>> >>> Thanks, >>> Tom >>> >>> 
>> ================== >>> Electric Druid >>> Synth & Stompbox DIY 
>>>>> ================== >>> >>>> On 11 Jun 2018, at 20:50, ASSI 
>> <Stromeko at nexgo.de> wrote: >>>> >>>> On Monday, June 11, 2018 
>> 7:43:22 AM CEST Elain Klopke wrote: >>>>> I was reading an 
>> article about the spectral content of various instruments >>>>> 
>> (woodwinds and strings) and while they didn't have any circuits, 
>> there were >>>>> some tables showing cutoff frequencies and high 
>> and low slopes. Several of >>>>> the pictures looked like 
>> bandpass filter responses with different slopes on >>>>> each 
>> side. How would I go about doing that? Is the slope determined by 
>> the >>>>> gain of the op amp in an active filter? If it's that 
>> easy, would it be a >>>>> highpass filter followed by a lowpass 
>> filter each with their own gain >>>>> settings? >>>> >>>> Both 
>> woodwinds and string instruments (among others) can be modeled 
>> with >>>> coupled resonators. The characteristic timbre of each 
>> is related to the modes >>>> of these resonators and the transfer 
>> of energy between them. The slopes of >>>> the bandpass skirts 
>> depend on both the quality factor of the resonator and the >>>> 
>> coupling strength to other resonators or resonator modes. 
>> Generally speaking, >>>> losing energy (e.g. into another mode) 
>> is a reduction in Q and hence shows up >>>> as a flattening of 
>> the slope. If you just want to approximate the magnitude >>>> 
>> response, a filter bank with a high enough number of filter bands 
>> is as good >>>> as any other method and relatively easy to 
>> implement, it just uses many de- >>>> coupled resonators instead 
>> of few(er) coupled ones. >>>> >>>> >>>> Regards, >>>> Achim. >>>> 
>> -- >>>> +<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk 
>> Blofeld]>+ >>>> >>>> Wavetables for the Terratec KOMPLEXER: >>>> 
>> http://Synth.Stromeko.net/Downloads.html#KomplexerWaves >>>> >>>> 
>>>>>>>>>> _______________________________________________ >>>> 
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>> ScottG >> 
>> ________________________________________________________________________ 
>>>> -- Scott Gravenhorst >> -- http://scott.joviansynth.com/ >> -- 
>> When the going gets tough, the tough use the command line. >> -- 
>> Matt 21:22 >> >> >> MIME-Version: 1.0 >> 
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>>> 
>> ________________________________________________________________________ 
>>> -- Scott Gravenhorst > -- http://scott.joviansynth.com/ > -- 
>> When the going gets tough, the tough use the command line. > -- 
>> Matt 21:22 > > _______________________________________________ > 
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> 
> -- ScottG
> ________________________________________________________________________
> -- Scott Gravenhorst
> -- http://scott.joviansynth.com/
> -- When the going gets tough, the tough use the command line.
> -- Matt 21:22
> 
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