New page on room acoustics, amplifier power, etc
 

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.

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.

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... :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

New page on room acoustics, amplifier power, etc
 

In article , Keith G
wrote:

"Jim Lesurf" wrote



I recently sold a turntable to someone who spotted my 'World Audio
Design' stuff when he came to collect it and said 'Ooh, do you read the
magazine?' I said no, not any longer and was going to go on and say
that I found that particular magazine had gone downhill of late and was
now full of meaningless purple prose and dubious factoids, but I
didn't....

Just as well, turns out he was/is the Deputy Editor of the magazine!
Anyway, he said the TT was going to featire in 'Audio Classics' (or
somesuch) and that he would send me a copy. He didn't ( no surprise
there) but a nearby friend still takes the mag and loaned me his
(March?) copy - shore 'nuff, the article was yet another wordy exercise
in meaningless 'purple prose' and just about the only single 'factoid'
in it (speed adjustment % figure) was *incorrect*!!

Which TT was it? My issue of HFW for March has an 'Olde Worlde' item
on the AIWA LP3000. Is that the one?



Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

New page on room acoustics, amplifier power, etc
 

"Dave Plowman (News)" wrote in message
...
In article ,
Keith G wrote:
('Clarity' should spark off a nice, busy, mile-long thread here -
once I slip the phrase 'fullrange driver' in somewhere! :-)

Is the last remark from golf or biking?... :-)



No it's a familiar contraction of something like 'a single speaker
driver system that provides enough of the meaningful extremes at both
ends of the spectrum to provide an adequate illusion of the full
freqency range of normal music, speech and soundtracks and render
unnecessary the employment of multiple drivers individually of varying
FR ranges and requisite crossover circuitry, thus avoiding the
inevitable, ensuant deterioration of the sound quality produced'....

The holy grail, then, since no such beast has been made. Unless the
'meaningful extremes' of your hearing is greatly reduced from the norm.


Absolutely right and the same can be said of almost every other normal
'hifi' speaker - including the ubiquitous and much-loved LS3/5A, as in this
old pic which I'm sure I've posted here befo

http://www.moirac.adsl24.co.uk/L1000309.JPG

Trust me, nice as they were/are, they had nothing on either of the
Lowther-powered speakers (Jerichos and Fidelios) and not even the bass
(IIRC) of the world-famous 'Pinkies' which can also be seen in the pic.

(Talking of 'Pinkies' - where's he gone? Was that just a little involuntary
*finger squirt* or summat? :-)

Anyhoo, in keeping with the point of Jim's article, interestingly you can
also see a 3.5wpc valve amp in the picture as well as the 100wpc (?) power
half on the high-end Technics amp I mentioned elsewhere. The valve amp
remains; the Technics is history....

(Btw, what happened to the 'Ay oop, Plowie - how're ya keeping? :-)' bit,
Plowie? Is it a *secret* or do you simply not care to say?? :-)

New page on room acoustics, amplifier power, etc
 

"Keith G" wrote in message
...

"David Looser" wrote in message
...

What is "clarity"? and how do you measure it?


With a knife and fork - just like how you measure the taste of a steak and
kidney pudding or the scent of a rose....

Exactly, it's pure subjectivity and thus utterly meaningless.

Here, see what you can do with this - what's the word: 'happy as xxx'?

http://www.moirac.adsl24.co.uk/Langu...r%20Clip-1.mp3

Here it is again in *vinyl*, if you prefer:

http://www.moirac.adsl24.co.uk/Langu...r%20Clip-2.mp3

:-)

Don't know why you posted those links, I haven't bothered to look at them
(the titles alone show that they have no relevance).

David.

New page on room acoustics, amplifier power, etc
 

"David Looser" wrote in message
...
"Keith G" wrote in message
...

"David Looser" wrote in message
...

What is "clarity"? and how do you measure it?


With a knife and fork - just like how you measure the taste of a steak
and kidney pudding or the scent of a rose....

Exactly, it's pure subjectivity and thus utterly meaningless.

Here, see what you can do with this - what's the word: 'happy as xxx'?

http://www.moirac.adsl24.co.uk/Langu...r%20Clip-1.mp3

Here it is again in *vinyl*, if you prefer:

http://www.moirac.adsl24.co.uk/Langu...r%20Clip-2.mp3

:-)

Don't know why you posted those links, I haven't bothered to look at them
(the titles alone show that they have no relevance).

David.




You didn't last long, did you?

(But I remember you always were a bit of a **** - see other response
also...)

New page on room acoustics, amplifier power, etc
 

"Keith G" wrote in message
...


(But I remember you always were a bit of a **** - see other response
also...)


Sorry Kieth, the "****" is you.

David.

New page on room acoustics, amplifier power, etc
 

In article ,
Keith G wrote:
The holy grail, then, since no such beast has been made. Unless the
'meaningful extremes' of your hearing is greatly reduced from the norm.


Absolutely right and the same can be said of almost every other normal
'hifi' speaker - including the ubiquitous and much-loved LS3/5A, as in
this old pic which I'm sure I've posted here befo

http://www.moirac.adsl24.co.uk/L1000309.JPG

The LS3/5a never claimed to be a full range monitor. It was designed for
broadcast use where space was at a premium. However, add a sub and it does
give the full range without filling the room with woodwork.

Trust me, nice as they were/are, they had nothing on either of the
Lowther-powered speakers (Jerichos and Fidelios) and not even the bass
(IIRC) of the world-famous 'Pinkies' which can also be seen in the pic.

Are you actually surpised a large speaker gives better bass?
However, those Lowthers also have a pretty horrid top end - as does any
other MC speaker of that size when you try and take it above about 4 kHz.

(Talking of 'Pinkies' - where's he gone? Was that just a little
involuntary *finger squirt* or summat? :-)

Dunno.

Anyhoo, in keeping with the point of Jim's article, interestingly you
can also see a 3.5wpc valve amp in the picture as well as the 100wpc
(?) power half on the high-end Technics amp I mentioned elsewhere. The
valve amp remains; the Technics is history....

You're just confirming you like a coloured sound - but then we knew that.

(Btw, what happened to the 'Ay oop, Plowie - how're ya keeping? :-)'
bit, Plowie? Is it a *secret* or do you simply not care to say?? :-)

You're interested in the state of my health? Or something else?
I'm fine thank you.

But how about you? After flouncing off from here saying you had better
things to do? What's changed?

--
*Don't squat with your spurs on *

Dave Plowman London SW
To e-mail, change noise into sound.

New page on room acoustics, amplifier power, etc
 

"David Looser" wrote in message
...
"Keith G" wrote in message
...


(But I remember you always were a bit of a **** - see other response
also...)


Sorry Kieth, the "****" is you.

David.



You think so?

I'm not the one who needs a meter to know when I like something, or know
when something is comparatively better - like the *night and day*
differences with some audio soundtracks on BDs which, you may be *amazed to
learn*, can be easily toggled between on the remote....

(Hint: You can't even get my name right and it's in the very post you
replied to! ;-)

New page on room acoustics, amplifier power, etc
 

"Dave Plowman (News)" wrote

The LS3/5a never claimed to be a full range monitor. It was designed for
broadcast use where space was at a premium. However, add a sub and it does
give the full range without filling the room with woodwork.


Says it all - for how long now has sound quality has been sacrificed for
'WAF' with speakers? (Why bother with a pipe organ when you can get a dinky
little Yamaha...??)


Are you actually surpised a large speaker gives better bass?


Lowthers don't do 'pistonic bass' either but they can do nice, clear low
notes - if you want unrealistic music (or realistic explosions) you will
need a sub with Lowthers also...



However, those Lowthers also have a pretty horrid top end - as does any
other MC speaker of that size when you try and take it above about 4 kHz.

(Talking of 'Pinkies' - where's he gone? Was that just a little
involuntary *finger squirt* or summat? :-)

Dunno.


Queer that - I hook the ng up for the first time in over a year and there's
a post from him right before my eyes!!

Then nothing!?



You're just confirming you like a coloured sound - but then we knew that.


Yep, nothing changes....



(Btw, what happened to the 'Ay oop, Plowie - how're ya keeping? :-)'
bit, Plowie? Is it a *secret* or do you simply not care to say?? :-)

You're interested in the state of my health? Or something else?


Oo-er, what do you mean? Just your general well-being is all...


I'm fine thank you.


Good. Delighted to hear it. I'm on about Day 112 of giving up smoking; I've
been better....



But how about you? After flouncing off from here saying you had better
things to do? What's changed?


Did I flounce? I don't remember....

We dropped Pipex a while back and went over to ADSL24 and for a long time
there was no sign of a newsfeed (turns out to be Entanet or summat) but,
after about the 20th fruitless attempt on my part, Swim handed me the
details the other evening. I wanted digital photography newsgroups as I have
subscribed to a couple of 'international' dp forums recently and I can't
stand them - I don't like the way the newly-confident Eurotrash treats Brit
posters and I don't like the sucky-up Brits who are trying (far too fakkn'
hard IMO) to get 'in'...!!

Anyway, I soon found the dp newsgroups aren't a lot of cop either and then
got the idea to look in here to see who was about - if anybody, as I've had
one or two people tell me it's been very quiet!

So....

I thought I'd lob a rock or two into the water here to see what wuz what!

:-)

New page on room acoustics, amplifier power, etc
 

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