[sdiy] converting white noise to pink noise

Eric Brombaugh ebrombaugh at earthlink.net
Tue Mar 4 16:53:35 CET 2008


How about programming a PIC12C50x part with a nice 32-bit LFSR 
algorithm? Those will run at 4MHz, so the repeat rate would be something 
on the order of 12 hours assuming a 100kHz sample rate (not unreasonable 
for a PIC). The parts cost ~$2. The program would be maybe 20 - 30 
instructions long. Noise would be white out to ~50kHz - well beyond 
human range.

Eric

Robert Lorentz wrote:
> My question is, since the MM5837 is garbage white noise on a chip,
> what is a better (preferably not obsolete) noise IC to use for this
> and other applications?
> 
> Robert
> 
> On 3/4/08, harrybissell at wowway.com <harrybissell at wowway.com> wrote:
>> LOL
>>
>> Make some ocean or wind sounds, listen to the little train
>> go chu-chug-chug in the background
>>
>> H^) harry
>>
>>
>> On Tue, 04 Mar 2008 06:19:18 -0700, Scott Gravenhorst wrote
>>> Yes, thanks Dave.
>>>
>>> I like this little bit:
>>>
>>> "The MM5837 provides a uniform noise quality..."
>>>
>>> shhh-tick-shhh-tick-shhh-tick-shhh-tick-shhh-tick-shhh-tick
>>>
>>> I guess "uniform" also includes the precise replication of the
>>> repeat pattern...
>>>
>>> John Mahoney <jmahoney at gate.net> wrote:
>>>> At 01:47 AM 3/4/2008, Dave Manley wrote:
>>>>
>>>>> I put a scan of the pink noise generator from the 1976 Audio Handbook here:
>>>>>
>>>>> http://www.sonic.net/~dlmanley/PinkNatSemiAudioHandbook1976.jpg
>>>>>
>>>>> The -3dB/octave response is claimed to be +/- 1/4dB from 10Hz to 40kHz.
>>>>>
>>>>> -Dave
>>>>
>>>> Aaaargh, it's the dreaded MM5837, again! Ah, well, it's fine for
>>>> testing purposes, it's just no good for making music.
>>>>
>>>> Thankfully, the pink noise filter is a separate circuit -- and it's
>>>> totally passive, to boot. Thank you, Dave.
>>>>
>>>> John
>>>>
>>>>
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>> 8:35 AM
>>>>
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>>> -- ScottG
>>>
>>> -----------------------------------------------------------------
>>>
>>> -- Scott Gravenhorst
>>> -- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
>>> -- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
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>>>
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>>
>> Harry Bissell & Nora Abdullah 4eva
>>
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