how good are class D amplifiers?
 

"Serge Auckland" wrote in message
...
Dave Plowman (News) wrote:
In article ,
Serge Auckland wrote:
Knowing Keith's equipment, it comes as no surprise:-

His horns have a sensitivity of about 100dB/watt, so his 8 watts
will provide a level of around 109dB.

Full range?

Full enough for the purposes. The missing bottom and top are already
way down on the F-M hearing curves that they won't change the
perceived loudness to any appreciable extent. The 100dB/watt
sensitivity figures are normally given at mid frequencies anyway.


There is no 'missing top' on any of the FR drivers I use here. Lower
register is a different story and depends on cabinet/placement &c., but
is frequently preferable to the thick, woolly bass of the TLs which
renders Classic FM (on FM) unlistenable, for example....

how good are class D amplifiers?
 

"Keith G" wrote in message
...

"Serge Auckland" wrote in message
...
Dave Plowman (News) wrote:
In article ,
Serge Auckland wrote:
Knowing Keith's equipment, it comes as no surprise:-

His horns have a sensitivity of about 100dB/watt, so his 8 watts
will provide a level of around 109dB.

Full range?

Full enough for the purposes. The missing bottom and top are already
way down on the F-M hearing curves that they won't change the
perceived loudness to any appreciable extent. The 100dB/watt
sensitivity figures are normally given at mid frequencies anyway.


There is no 'missing top' on any of the FR drivers I use here.


I guess I should have said *audible* missing top - I'm not too bothered
what may or may not show up on Plowie's rectum analyser...

how good are class D amplifiers?
 

"Keith G" wrote in message
...

"Keith G" wrote in message
...

"Serge Auckland" wrote in message
...
Dave Plowman (News) wrote:
In article ,
Serge Auckland wrote:
Knowing Keith's equipment, it comes as no surprise:-

His horns have a sensitivity of about 100dB/watt, so his 8 watts will
provide a level of around 109dB.

Full range?

Full enough for the purposes. The missing bottom and top are already way
down on the F-M hearing curves that they won't change the perceived
loudness to any appreciable extent. The 100dB/watt sensitivity figures
are normally given at mid frequencies anyway.


There is no 'missing top' on any of the FR drivers I use here.


I guess I should have said *audible* missing top - I'm not too bothered
what may or may not show up on Plowie's rectum analyser...


I'm glad you qualified the *audible* missing top. It may not be audible,
certainly not to a 60 year old, (or one only a few years behind you), but
missing it certainly is when measured. Lowther claim 18-20kHz for their
drivers, but they don't say either how far down that is, or at what angle
from the drive unit centre. Single drive units beam very significantly, so
for younger listeners, they would most certainly have "missing" top,
especially if listening anything other than straight-on.

I don't understand the statement about the woolly bass of the TLs, as the
IMFs have about the cleanest tightest bass immaginable. Maybe they are
going sufficiently far down that they set off room resonances that your
horns don't go near. Have you tried them in your large room?

S.

how good are class D amplifiers?
 

In article ,
Keith G wrote:
You *are* kidding - right...???

No. I assumed you'd have such a programme given the money you spend on
mics etc and the amount of recordings you put on your site via a
computer.

No - missing the point as ever. What I was commenting on was the your
suggestion to someone who said he couldn't hear a difference that he
should *measure* it until he can...

My reasoning is it might give a clue as to what to listen for.

--
*Tell me to 'stuff it' - I'm a taxidermist.

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

how good are class D amplifiers?
 

In article ,
Keith G wrote:
I'd suggest you try again - it's at the top of this post. If you can't
tell a resistor from a capacitor you should stick to low voltage
battery operated equipment. Valve equipment fiddled with by the
totally unskilled can be a fire risk.


Wake up FFS - try to spot when someone's taking the ****....

Very difficult with you Keith because so much you say and presumably mean
would be considered 'taking the ****' by many.

(Look up 'Socratic Irony and scale it down to *country boy* part
feigned/mostly real ignorance and you'll be in the right neck of the
woods... ;-)

Seems strange you like to poo-poo the acquiring of even vague technical
knowledge - when it suits you. Considering how much you mention the things
you've built.

--
*Organized Crime Is Alive And Well; It's Called Auto Insurance.

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

how good are class D amplifiers?
 

In article ,
Keith G wrote:
There is no 'missing top' on any of the FR drivers I use here.

Depends on what you mean by 'missing'. And top.

--
*I'm out of my mind, but feel free to leave a message.

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

how good are class D amplifiers?
 

"Jim Lesurf" wrote in message
...
In article , Serge Auckland
wrote:
Dave Plowman (News) wrote:
In article , Serge Auckland
wrote:
Knowing Keith's equipment, it comes as no surprise:-

His horns have a sensitivity of about 100dB/watt, so his 8 watts will
provide a level of around 109dB.

Full range?

Full enough for the purposes. The missing bottom and top are already way
down on the F-M hearing curves that they won't change the perceived
loudness to any appreciable extent. The 100dB/watt sensitivity figures
are normally given at mid frequencies anyway.

That may be drawing an incorrect conclusion by misapplying the curves.

The key point will be that the music either will have audible bass/treble
when replayed with a 'flat' system or not. (By rthat, I mean that the
presence of the low bass and high treble have an audible effect.)

If it does, then using speakers that fail to reproduce the bass/treble
will
alter the audible results.

The FM curves simply imply that a higher sound pressure was required in
the
first place for the music to have the audible bass/treble.

The curves were also based on isolated sinewave audibility IIRC. This
isn't
at all the same thing as when listening to a composite sound as the
physiology, etc, of human hearing system isn't simply working by linear
superposition.

Slainte,

Jim


Indeed, and for a rigorous explanation I fully agree. However, what I was
trying to get across as that the perceived loudness mostly comes from
mid-high frequency energy, consequently missing the extreme botom and top
won't make a large difference to the perceived loudness. With music the
frequency exrtemes are already well down on the mid frequencies, and add to
that the falling sensitivity of the ear, loudness won't chenge much by
adding the extremes. It will of course make a difference to the perceived
sound quality, but that's not what we were discussing, merely loudness.

S.

how good are class D amplifiers?
 

"Dave Plowman (News)" wrote in message
...
In article ,
Keith G wrote:
You *are* kidding - right...???

No. I assumed you'd have such a programme given the money you spend
on
mics etc and the amount of recordings you put on your site via a
computer.

No - missing the point as ever. What I was commenting on was the your
suggestion to someone who said he couldn't hear a difference that he
should *measure* it until he can...

My reasoning is it might give a clue as to what to listen for.


Why search for what you don't want?

All 'audio reproduction' is illusion by the time it reaches the ears...

how good are class D amplifiers?
 

"Dave Plowman (News)" wrote in message
...
In article ,
Keith G wrote:
I'd suggest you try again - it's at the top of this post. If you
can't
tell a resistor from a capacitor you should stick to low voltage
battery operated equipment. Valve equipment fiddled with by the
totally unskilled can be a fire risk.


Wake up FFS - try to spot when someone's taking the ****....

Very difficult with you Keith because so much you say and presumably
mean
would be considered 'taking the ****' by many.


You've also never twigged that I pay back in the same coin I'm paid - if
you perceive a high level of ****take in my responses perhaps you should
look at your own posts....



(Look up 'Socratic Irony and scale it down to *country boy* part
feigned/mostly real ignorance and you'll be in the right neck of the
woods... ;-)

Seems strange you like to poo-poo the acquiring of even vague
technical
knowledge - when it suits you.



I don't poo poo technical knowledge, I only choose to restrict how much
I'm prepared to let it upset my preferred state of Blissful Ignorance
and actively avoid acquiring (or making the effort to acquire) that
which I feel I don't need to know. Summat comes up I gotta know, I ask
(have done on here millions of times) or I Google it to death until I've
learned enough to get by.

(Ask yerself, Plowie - when did you *ever* see a capacitor with 'not a
resistor' stamped on it - couldn't you see even a glimmer of humour in
that one?)


Considering how much you mention the things
you've built.


You mean how much *you* mention the things I've built...??

how good are class D amplifiers?
 

"Serge Auckland" wrote


Indeed, and for a rigorous explanation I fully agree. However, what I
was trying to get across as that the perceived loudness mostly comes
from mid-high frequency energy, consequently missing the extreme botom
and top won't make a large difference to the perceived loudness. With
music the frequency exrtemes are already well down on the mid
frequencies, and add to that the falling sensitivity of the ear,
loudness won't chenge much by adding the extremes. It will of course
make a difference to the perceived sound quality, but that's not what
we were discussing, merely loudness.


Exactly.

As to 'sound quality' with and/or without (audible) frequency extremes -
I'm in the middle of making multiple amp/speaker comparisons to see if I
can break the SS/TL, triode/horns *given* right now and might post some
trax when I have got to the 'bottom line'!!

(All I can say so far is 'apples and apples' it ain't!!)