Before I get out my oscilloscope and check, does anyone know how a
typical AV amp crossover behaves?
That is, when the main speakers are set to small, the sub-out has a
low-pass filter
and the other outputs have high-pass filters, but what order and type?
If implemented digitally, I would expect a high order filter.
I wouldn't know if they all use the same chips and algorithms.

--
Eiron.

"Eiron" wrote in message
...
Before I get out my oscilloscope and check, does anyone know how a typical
AV amp crossover behaves?
That is, when the main speakers are set to small, the sub-out has a
low-pass filter
and the other outputs have high-pass filters, but what order and type?
If implemented digitally, I would expect a high order filter.
I wouldn't know if they all use the same chips and algorithms.


Your oscilloscope won't tell you much, unless you use it as part of a
swept-frequency analyser.

The filters are implemented inside DSPs, but ~I wouldn't expect high-order
filters to avoid audible problems in the region of the cross-over.

It would be worth looking at the manufacturers specs to see if they state
the type and order of the cross-over filters.

David.

On 06/12/2010 17:33, David Looser wrote:
"Eiron" wrote in message
...
Before I get out my oscilloscope and check, does anyone know how a typical
AV amp crossover behaves?
That is, when the main speakers are set to small, the sub-out has a
low-pass filter
and the other outputs have high-pass filters, but what order and type?
If implemented digitally, I would expect a high order filter.
I wouldn't know if they all use the same chips and algorithms.


Your oscilloscope won't tell you much, unless you use it as part of a
swept-frequency analyser.

The filters are implemented inside DSPs, but ~I wouldn't expect high-order
filters to avoid audible problems in the region of the cross-over.

It would be worth looking at the manufacturers specs to see if they state
the type and order of the cross-over filters.

An oscilloscope will tell me the gain and phase shift at various
frequencies when I feed the amp with a sine wave.
Have you seen any manufacturers spec sheets that go into such detail?

--
Eiron.

"Eiron" wrote

An oscilloscope will tell me the gain and phase shift at various
frequencies when I feed the amp with a sine wave.

Scopes are fine for rough amplitude and phase measurements, but for the sort
of precision measurements you would need to obtain the information you are
talking about they really don't cut the mustard.

Have you seen any manufacturers spec sheets that go into such detail?

Yes I have, for the more up-market and professional gear. I reckon that's
your best bet, unless you can lay your hands on a proper swept-frequency
analyser.

The real question, I suppose, is why do you want to know? Is this just idle
curiosity, or do you have some dark purpose?

David.

In article , David Looser
wrote:
"Eiron" wrote

An oscilloscope will tell me the gain and phase shift at various
frequencies when I feed the amp with a sine wave.

Scopes are fine for rough amplitude and phase measurements, but for the
sort of precision measurements you would need to obtain the information
you are talking about they really don't cut the mustard.

I have a vague recollection that Keith Howard published some measurements
of LF crossover rates and 'ringing' a year or two ago. But I can't recall
details. If I find out I'll say.

Slainte,

Jim

--
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