Jim Lesurf wrote:

Eeyore wrote:
Jim Lesurf wrote:

FWIW The effect of room reverb in UK domestic rooms might be somewhat
higher than a 3dB gain. I did some analysis of this a while ago (see
Hi Fi News August 2008). Hard to give a figure as it will probably
vary from room to room, but 3dB may be on the low side as an estimate
of what is typical. IIRC some texts also give details that indicate
well above 3dB for this.

3dB relative to WHAT ?

If you look at what Stewart wrote (Hi, Stewart! :-) ) that seems to be
comparing the effect of the room reverb with a situation where such reverb
would be absent. At least that is my understanding of his saying,
"...having them in an average living room gives you another 3dB or so of
reverberant sound..." If that is wrong, I'm sure he will correct me, but
that was what I then was referring to. Sorry if you didn't follow what I
wrote.

It's certainly true that a domestic room will have a far or ambient field that
is greater than an anechoic chanber. Ever been in one btw ? They're really odd.

But then again does one listen to one's speakers at 1 metre distance usually ?
so the SPL will have dropped off by X dB anyway by the time it reaches the
sofa.


Are you familiar with nearfield and farfield measurements ?

Yes - although you haven't said which particular mechanisms you have in
mind for the factor(s) which affect how they differ, so I don't know which
one(s) you have in mind. Have you read the article I referred to?

Don't need to. In the near field, SPL will drop off at a rate of 6dB per
doubling of distance (inverse square law). In the far field it's anyone's guess
due to all the factors previously mentioned. Where the far field begins depends
the size of your room and those other factors.


That said (again as discussed in the HFN article) there is a
distinction between the actual instantaneous peak measured power, and
the peak level perceived, due to the way human hearing tends to
'integrate' the effect of short term delayed reflections into one
percieved peak.

Quite. It's not simple.

That was indeed, part of my point. :-)

Ok.

Graham