To pursue an academic thought (rather than a desire to annoy the
neighbours) I was thinking about whether "orchestral" sound pressure
levels can be reasonably achieved at home.

I think the answer is yes, from just personal listening experience in
the concert hall (classical orchestral music, not normally closer to the
stage than 10 metres) and listening at home. However the more academic
answer depends on at least two factors:

1. What peak SLPs are achieved in a reasonably good seat in a concert
hall where an orchestra is playing, say 10 metres from the front
centre of the orchestra?

2. What reasonable (relatively undistorted) peak SPLs will normal but
good quality home audio kit produce?

The answer to 2 looks fairly simple. Peak SPLs about 109 dBA seem
theoretically achieveable at 1 metre from an average sensitivity
loudspeaker (about 89 dBA for a nominal eight-ohm Watt, I think) driven by
a 100 W amplifier (+20 dBW). I think also that a reasonably good modern
loudspeaker could, in practice, go up to to 109 dBA on occasional peaks
(is this correct?).

Compensating for (i) being, say, 3 metres away from the speakers, but in
a non-anechoic space, and (ii) having two loudspeakers, I think that 109
dBA probably comes down to 103 to 106 dBA peak SPL at the listening chair
(still VERY LOUD, nevertheless).

However, the answer to 1 ("orchestral SPLs?") has eluded a quick Google
search. Yes, lots of SPL figures can be found for an orchestra but they
vary widely and so far none I have seen is adequately qualified to answer
the question.

Are there any good references to orchestral SPLs in the auditorium? The
best references I have found are to SPLs in the context of the exposure of
the musicians themselves to high SPLs but I don't think these measurements
are easily translatable to SPLs in the hall.

--
John Phillips

John Phillips wrote:
To pursue an academic thought (rather than a desire to annoy the
neighbours) I was thinking about whether "orchestral" sound pressure
levels can be reasonably achieved at home.

I think the answer is yes, from just personal listening experience in
the concert hall (classical orchestral music, not normally closer to
the stage than 10 metres) and listening at home. However the more
academic answer depends on at least two factors:

1. What peak SLPs are achieved in a reasonably good seat in a concert
hall where an orchestra is playing, say 10 metres from the front
centre of the orchestra?

2. What reasonable (relatively undistorted) peak SPLs will normal but
good quality home audio kit produce?

The answer to 2 looks fairly simple. Peak SPLs about 109 dBA seem
theoretically achieveable at 1 metre from an average sensitivity
loudspeaker (about 89 dBA for a nominal eight-ohm Watt, I think)
driven by a 100 W amplifier (+20 dBW). I think also that a reasonably
good modern loudspeaker could, in practice, go up to to 109 dBA on
occasional peaks (is this correct?).

Compensating for (i) being, say, 3 metres away from the speakers, but
in a non-anechoic space, and (ii) having two loudspeakers, I think
that 109 dBA probably comes down to 103 to 106 dBA peak SPL at the
listening chair (still VERY LOUD, nevertheless).


http://www.yeodoug.com/resources/faq...iselevels.html (Near the
end)

As you say, these are measured in the orchestra rather than from the
audience, but since you are using theoretical extrapolations for 2)
rather than measurement, why not do the same with the figures for the
violin, for example?

HTH

Neil

In article , Neil Jones wrote:
http://www.yeodoug.com/resources/faq...iselevels.html (Near the
end)

As you say, these are measured in the orchestra rather than from the
audience, but since you are using theoretical extrapolations for 2)
rather than measurement, why not do the same with the figures for the
violin, for example?

Many thanks - some useful figures which are very helpful. However,
as with other measurements taken within the orchestra itself, I know
of no way to extrapolate near field, essentially single-instrument
SPL figures to a SPL for the entire orchestra in the far field region
(i.e. within the audience).

--
John Phillips

John Phillips wrote:
In article , Neil Jones wrote:
http://www.yeodoug.com/resources/faq...iselevels.html (Near
the end)

As you say, these are measured in the orchestra rather than from the
audience, but since you are using theoretical extrapolations for 2)
rather than measurement, why not do the same with the figures for the
violin, for example?

Many thanks - some useful figures which are very helpful. However,
as with other measurements taken within the orchestra itself, I know
of no way to extrapolate near field, essentially single-instrument
SPL figures to a SPL for the entire orchestra in the far field region
(i.e. within the audience).

I wonder to what extent the measurements results from the individual (ie
the near-field) vs the sound from the rest of the orchestra.

Neil Jones pibbled:
John Phillips wrote:
To pursue an academic thought (rather than a desire to annoy the
neighbours) I was thinking about whether "orchestral" sound pressure
levels can be reasonably achieved at home.


2. What reasonable (relatively undistorted) peak SPLs will normal but
good quality home audio kit produce?

The answer to 2 looks fairly simple. Peak SPLs about 109 dBA seem
theoretically achieveable at 1 metre from an average sensitivity
loudspeaker (about 89 dBA for a nominal eight-ohm Watt, I think)
driven by a 100 W amplifier (+20 dBW). I think also that a reasonably
good modern loudspeaker could, in practice, go up to to 109 dBA on
occasional peaks (is this correct?).


About right. Hi-Fi Choice used to measure maximum SPL's, and big, efficient
speakers driven hard can reach this. Most top out at 105, and are
struggling very hard by then. Given the distortion, they probably sounded
louder than the big ones.

Compensating for (i) being, say, 3 metres away from the speakers, but
in a non-anechoic space, and (ii) having two loudspeakers, I think
that 109 dBA probably comes down to 103 to 106 dBA peak SPL at the
listening chair (still VERY LOUD, nevertheless).


http://www.yeodoug.com/resources/faq...iselevels.html (Near the
end)


Bloody hell. 128dB in front of the bassoon! Am I wrong, or would your ears
go into 'self-protect' mode at this level, possibly hugely affecting the
performance of the musician?

As you say, these are measured in the orchestra rather than from the
audience, but since you are using theoretical extrapolations for 2)
rather than measurement, why not do the same with the figures for the
violin, for example?


Found this: http://www.lhh.org/noise/decibel.htm
although as it's a 'pressure' group (sic) the levels may be distorted!

Regardless, my stereo isn't going to go there. Shame, I thought it did.
Perhaps a subwoofer would help.

--
Despite appearances, it is still legal to put sugar on cornflakes.
Strawberries are purely optional.

In article , Triffid wrote:
Neil Jones pibbled:
http://www.yeodoug.com/resources/faq...iselevels.html (Near the
end)

Bloody hell. 128dB in front of the bassoon! Am I wrong, or would your ears
go into 'self-protect' mode at this level, possibly hugely affecting the
performance of the musician?

Threshold of pain is said to be 130 dB on that scale. The conclusion
of http://www.symphony.dk/sektion2/audiograms.htm is a qualified:

"Based on the measured audiograms it may be concluded that musicians
can not expect to achieve pronounced hearing losses from playing in an
symphony orchestra. ..."

--
John Phillips

John Phillips wrote:
To pursue an academic thought (rather than a desire to annoy the
neighbours) I was thinking about whether "orchestral" sound pressure
levels can be reasonably achieved at home.

I think the answer is yes, from just personal listening experience in
the concert hall (classical orchestral music, not normally closer to the
stage than 10 metres) and listening at home. However the more academic
answer depends on at least two factors:

1. What peak SLPs are achieved in a reasonably good seat in a concert
hall where an orchestra is playing, say 10 metres from the front
centre of the orchestra?

2. What reasonable (relatively undistorted) peak SPLs will normal but
good quality home audio kit produce?

The answer to 2 looks fairly simple. Peak SPLs about 109 dBA seem
theoretically achieveable at 1 metre from an average sensitivity
loudspeaker (about 89 dBA for a nominal eight-ohm Watt, I think) driven by
a 100 W amplifier (+20 dBW). I think also that a reasonably good modern
loudspeaker could, in practice, go up to to 109 dBA on occasional peaks
(is this correct?).

Compensating for (i) being, say, 3 metres away from the speakers, but in
a non-anechoic space, and (ii) having two loudspeakers, I think that 109
dBA probably comes down to 103 to 106 dBA peak SPL at the listening chair
(still VERY LOUD, nevertheless).

However, the answer to 1 ("orchestral SPLs?") has eluded a quick Google
search. Yes, lots of SPL figures can be found for an orchestra but they
vary widely and so far none I have seen is adequately qualified to answer
the question.

Are there any good references to orchestral SPLs in the auditorium? The
best references I have found are to SPLs in the context of the exposure of
the musicians themselves to high SPLs but I don't think these measurements
are easily translatable to SPLs in the hall.


I have never heard it expressed in SPL but a long time ago I read that
the peak output from an orchestra is about 70 watts of acoustic power.
You should be able to work it out from that.

Ian

ruffrecords wrote:


I have never heard it expressed in SPL but a long time ago I read that
the peak output from an orchestra is about 70 watts of acoustic power.
You should be able to work it out from that.

Domestic speakers are about 1% efficient.
That might help.

Eiron wrote:
ruffrecords wrote:


I have never heard it expressed in SPL but a long time ago I read that
the peak output from an orchestra is about 70 watts of acoustic power.
You should be able to work it out from that.


Domestic speakers are about 1% efficient.
That might help.

What you really need to know is the watts/sq metre. Assuming the
inverse square law applies then 70W acoustic heard at 10 metres is
equivalent to 70/(10*10) = 0.7W acoustic at 1metre. If your speakers
are 1% efficient then you need to feed them 70W to achieve this.

This math seems to simple. Is it right?

Ian

On Thu, 26 Aug 2004 23:11:09 +0100, Eiron wrote:

ruffrecords wrote:

I have never heard it expressed in SPL but a long time ago I read that
the peak output from an orchestra is about 70 watts of acoustic power.
You should be able to work it out from that.

Domestic speakers are about 1% efficient.

That would be about 89dB/w/m, but bear in mind that some designs such
as the Avantgarde Trio horn can achieve 103dB/w/m - and horns don't
obey the inverse square law!
--

Stewart Pinkerton | Music is Art - Audio is Engineering