Re: Why Is High Feedback Considered Bad In Audio? In Simple Terms

On Jan 27, 12:51 pm, John Larkin
<jjlar...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
On Sun, 25 Jan 2009 20:43:35 -0800, JosephKK <quiettechb...@xxxxxxxxx>
wrote:



On Sun, 25 Jan 2009 11:58:51 -0600, Vladimir Vassilevsky
<antispam_bo...@xxxxxxxxxxx> wrote:

John Larkin wrote:

If a thing rings, it rings forever.

Good point.

A simple CR doesn't ring, it thuds.

Definition of thud?

Leftist weenies thud, rattle or ring. Engineers talk numbers and
formulas :-)

How about this:

HPF = 1 - LPF

If LPF is rings, then HPF rings, too.

VLV

And likewise if the LPF does not ring the HPF does not ring.

And since lots of lowpass filters don't overshoot, they don't ring, so
there must be highpass filters that don't ring.

This makes less and less sense all the time.

John

I know you can't make a high pass that is linear phase. [Highpass in
the true sense, i.e. zeros at DC/] A highpass filter has no delay at
infinite frequency, but has delay near it's corner. There may be a
highpass/allpass combo that makes a net filter that is linear phase.
Of course, linear phase doesn't always translate into no ringing.

One thing to investigate would the Linkwitz-Riley (sp) class of
highpass filters. My recollection is they take an optimal delay and
subtract a Bessel to get a highpass. The idea was to get a smooth
response at the crossover.
.

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