"Stewart Pinkerton" wrote in message
...
On Sun, 4 Jan 2004 00:01:48 +0000 (UTC), "David"
wrote:

No. Highly efficient speakers are generally less accurate than "lowish"
efficiency speakers. They tend to become unlinear at high outputs.

Actually, the exact opposite is true. It's insensitive speakers that
have problems at high SPLs, for reasons which should be obvious.

Erm, remind me!!




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On Sun, 04 Jan 2004 19:35:50 GMT, Form@C wrote:

Maybe not, but do you want *accurate* reproduction or an amp that is good
to listen to?

Accurate reproduction please. I want to hear the music as it was
recorded, with (as far as possible) nothing added or taken away,
rather than some hi-fi equipment designer's vision of what music
*should* sound like.

--
Anthony Edwards

On Sun, 04 Jan 2004 19:35:50 GMT, Form@C wrote:

Maybe not, but do you want *accurate* reproduction or an amp that is good
to listen to?

Accurate reproduction please. I want to hear the music as it was
recorded, with (as far as possible) nothing added or taken away,
rather than some hi-fi equipment designer's vision of what music
*should* sound like.

--
Anthony Edwards

Roy wrote:


Actually, the exact opposite is true. It's insensitive speakers that
have problems at high SPLs, for reasons which should be obvious.


Erm, remind me!!


I would guess, because to get high SPL with insensitive speakers
involves large amounts of power, large amounts of power needs to go
somewhere as heat. Sensitive speakers can produce equivilant SPL without
needing to cope with all the heat.

Don't know if its still the case, but in my day, large PA speakers were
always as sensitive as possible, and often horn loaded for this very
reason.

--
Nick

Roy wrote:


Actually, the exact opposite is true. It's insensitive speakers that
have problems at high SPLs, for reasons which should be obvious.


Erm, remind me!!


I would guess, because to get high SPL with insensitive speakers
involves large amounts of power, large amounts of power needs to go
somewhere as heat. Sensitive speakers can produce equivilant SPL without
needing to cope with all the heat.

Don't know if its still the case, but in my day, large PA speakers were
always as sensitive as possible, and often horn loaded for this very
reason.

--
Nick

On Sun, 04 Jan 2004 20:03:05 +0000, Anthony Edwards wrote:

On Sun, 04 Jan 2004 19:35:50 GMT, Form@C wrote:

Maybe not, but do you want *accurate* reproduction or an amp that is
good to listen to?

Accurate reproduction please. I want to hear the music as it was
recorded, with (as far as possible) nothing added or taken away, rather
than some hi-fi equipment designer's vision of what music *should* sound
like.

Then go to a *lot* of live performances & build your own amp based on what
you hear. You won't get what you want from a spec sheet! :-)

Above all, don't buy without hearing the gear. Capture some voice radio
broadcasts, burn them to a CD & take it with you. The gear should be able
to recreate the sound of live voices.

--
Mick
http://www.nascom.info for Nascom & Gemini information
Also at http://www.mixtel.co.uk where the collection started.
Currently deserting M$ for linux... :-)

On Sun, 04 Jan 2004 20:03:05 +0000, Anthony Edwards wrote:

On Sun, 04 Jan 2004 19:35:50 GMT, Form@C wrote:

Maybe not, but do you want *accurate* reproduction or an amp that is
good to listen to?

Accurate reproduction please. I want to hear the music as it was
recorded, with (as far as possible) nothing added or taken away, rather
than some hi-fi equipment designer's vision of what music *should* sound
like.

Then go to a *lot* of live performances & build your own amp based on what
you hear. You won't get what you want from a spec sheet! :-)

Above all, don't buy without hearing the gear. Capture some voice radio
broadcasts, burn them to a CD & take it with you. The gear should be able
to recreate the sound of live voices.

--
Mick
http://www.nascom.info for Nascom & Gemini information
Also at http://www.mixtel.co.uk where the collection started.
Currently deserting M$ for linux... :-)

Hi,

In message , "Form@C"
writes

So, given fairly inefficient speakers of about 60dB/W you *need* less than
2W to reach that SPL. Double it to add some headroom. Say 5W. Even small
bookshelf speakers can be about 90dB/W, so this is loud.

60dB/W (I assume you mean at 1 metre) is more than fairly inefficient in
loudspeaker terms: it's unusable!

If you put an orchestral peak at, say, 200dB (way too high, I know - it
would deafen the conductor.)

Not only that, it would blow the auditorium apart, assuming it were
achievable.

, the SPL at your listening position at, say,
197dB (lost half of it)

It would still blow the house down, even if you *had* lost half of it
:-)

and your speaker efficiency at, say, 60dB/w
(fairly poor sealed boxes) then you need 4W to hit the peak volume. A 5W
amp is overkill. :-)

A 5 watt amplifier driving 60dB/W speakers would be less than impressive
- definitely not overkill!


--
Regards,
Glenn Booth

Hi,

In message , "Form@C"
writes

So, given fairly inefficient speakers of about 60dB/W you *need* less than
2W to reach that SPL. Double it to add some headroom. Say 5W. Even small
bookshelf speakers can be about 90dB/W, so this is loud.

60dB/W (I assume you mean at 1 metre) is more than fairly inefficient in
loudspeaker terms: it's unusable!

If you put an orchestral peak at, say, 200dB (way too high, I know - it
would deafen the conductor.)

Not only that, it would blow the auditorium apart, assuming it were
achievable.

, the SPL at your listening position at, say,
197dB (lost half of it)

It would still blow the house down, even if you *had* lost half of it
:-)

and your speaker efficiency at, say, 60dB/w
(fairly poor sealed boxes) then you need 4W to hit the peak volume. A 5W
amp is overkill. :-)

A 5 watt amplifier driving 60dB/W speakers would be less than impressive
- definitely not overkill!


--
Regards,
Glenn Booth

On Sun, 04 Jan 2004 19:47:06 +0000, Fleetie wrote:

"Form@C" wrote
If you put an orchestral peak at, say, 200dB (way too high, I know - it
would deafen the conductor.),

If by "dB" you mean the normal decibel used to measuring sound pressure
level (20 * log_10(p / 2.0E-5) ), then it would not deafen the conductor.
It would kill him and pulp his body.


Too true! 130dB is threshold of pain, is it not? I was thinking of
transients really, not actual output from the orchestra. 200dB is, of
course, ludicrous, but it is on the right (high) side of reality!


the SPL at your listening position at, say, 197dB (lost half of it) and
your speaker efficiency at, say, 60dB/w (fairly poor sealed boxes) then
you need 4W to hit the peak volume. A 5W amp is overkill. :-)

Erm, no.

You should not use the notation "dB/W" because it doesn't work like that.
Correctly, you should specify speaker sensitivity as "X dB at 1W input
power" (at some frequency). Some manufacturers instead say "X dB at 2.83V"
(being 2*pi) RMS input (at some frequency), which is a similar thing,
because P = V^2 / Z. If R=8 Ohms at the test frequency, then the power
will be 1 watt. But only if Z=8 Ohms at that frequency, and in general, it
won't be.


Point taken.
Right, the (transient!) SPL at the concert seat could hit around 190dB.

Example: Kef Coda 70: 2.83v/1m 91dB, 8R, frequency not stated (efficient
for small boxes). So at, say, 4m away you get 79dB at your listening
position for 1W at the speakers (it appears to be 6dB each time the
distance is doubled). So, for our 190dB we need 2.5W at the speaker? Ok,
not a lot of bass in that little box (-3dB at 45Hz), and they have a max
output of 109dB anyway, but you get the idea... 5W is still a lot.

--
Mick
http://www.nascom.info for Nascom & Gemini information
Also at http://www.mixtel.co.uk where the collection started.
Currently deserting M$ for linux... :-)