[sdiy] removing dc offset

[Scott Gravenhorst]

What happens if you take the cutoff below 300 Hz?

If the DC offset is constant, it should be eliminated by _any_ size
capacitor.  It's just that smaller ones will have a higher cutoff frequency
and will attenuate bass more as the capacitor is decreased in size.  I don't
believe the problem is the filter slope.


"gregory zifcak" <zifcak at hotmail.com> wrote:
>this is what i was doing, but i have to use a cutoff frequency of about 300 
>hz to substantially reduce the dc. i'm assuming this is because the 6db 
>slope is just not steep enough.
>i guess that because the toy originally used a small internal speaker, they 
>didn't need to worry about the dc. i've added an output and i'm worried 
>about damaging speakers with the thump.
>>
>>Are you using a capacitor in series with the output as a DC blocking
>>capacitor?  It needs to be larger for lower frequencies to pass through
>>it.  It's really a simple highpass filter, so the larger the cap, the
>>lower the cutoff.
>>
>> >--- gregory zifcak <zifcak at hotmail.com> wrote:
>> >
>> >> hi,
>> >> i am modifying a toy that has very rich bass, but due to the fact
>> >> that it is
>> >> run from a single battery supply, there is a dc offset. i've tried
>> >> filtering
>> >> this with caps of various sizes, but i can't seem to get rid of the
>> >> offset
>> >> without getting rid of the bass. is there a simple way to do this?
>> >> thanks for any suggestions,
>> >> greg
>> >>
>> >>
>> >>
>> >
>> >
>> >
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>>-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
>>-- Linux Rex         | RedWebMail by RedStarWare
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>>
>
>

---------------------------------------------------------
- Where merit is not rewarded, excellence fades.
- Hydrogen is pointless without solar.
- What good are laws that only lawyers understand?
- The media's credibility should always be questioned.
- The only good terrorist is a dead terrorist.
- Governments do nothing well, save collect taxes.

-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
-- Linux Rex         | RedWebMail by RedStarWare
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- Autodidactic Master of Arcane and Hidden Knowledge.