On Mon, 06 Apr 2009 18:17:32 +0100, Jim Lesurf
wrote:

In article 49da1d8d.6281046@localhost, Don Pearce
wrote:
On Sun, 05 Apr 2009 17:48:43 +0100, Jim Lesurf
wrote:

Hi,

Just to let people know I've just put up a new page which looks at the
effects of room acoustics and human hearing. In particular, to assess
the amplifier powers people might need. For reasons that should be
clear if you read it, the item is called "Imagine a Room Full of
Mirrors". :-)

When I get a chance I'll also put up the first two HFN articles I did
on 'Speaker Cables'.

Slainte,

Jim

Interesting article - do you think this will extrapolate to the ultimate
small room, a set of headphones? What I'm thinking about is the
interaction between what you hear and what you see. I mean, if you are
listening with headphones in large or small rooms, do your acoustic
perceptions of what you hear change as a result?

That is a somewhat different issue since - if I understand you correctly -
you are meaning being affected by what you *see*. The analysis I did was to
assess the effects in terms of perceived volume depending on a short-term
integration in human hearing, and the time domain profile of the 'echos' in
domestic rooms.

In effect I'd expect *all* 'echos' inside headphones to fall within the
integration time. Also, for in-ear or closed back the behaviour becomes a
pressure variation determined by the volume being changed by the 'speaker'
movements. But this strikes me as totally different topic to the one I
considered.


Not entirely different, because this is after all about perception,
and this is a factor in that perception. It is, if you like, an
uncontrolled (uncontrollable) variable in your thesis. The question
is, how big? Is it first, second or third order? I don't have an
answer to that, but for me it is certainly perceptible in daily
listening.

The "right" volume for me depends on a great many things, room size
being one of them. Another would be the time of day, whether the
neighbours are home etc. I don't really think "shame but I'd better keep
the volume down", the preferred volume actually changes.

Yes. I think you can expect the sensitivity, etc, of hearing to change with
time of day and many other factors. But as above I wasn't considering that.
Just what change in amp power you might need for a change of room size when
all else was equal.


OK, I see that. How much of your conclusion do you think is inductive,
and how much deductive?

So I think this probably has a great deal further to go than the simple
acoustic interaction of room size and the formation of resonance.

Agreed. But I didn't attempt to do all things for one 3-4 page article. No
doubt these are topics for future articles... :-)


Time they gave you a whole issue, then!

d