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Old 7th November 2012, 12:38 AM   #29031
fas42 is online now fas42  Australia
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Originally Posted by kgrlee View Post
It's not the average levels but the peak levels which are a problem. I used to sing with a choir that often sat in front of the brass section so I know how loud this gets.

Recording good small choirs is more difficult. There are various levels of 'in-tune'. If good enough, a choir of 12-20 can sometime show amazing peaks at very modest levels. What happens is that they sing so 'in tune', they add 6dB rather than 3dB for 2 voices for very short periods. When this happens, the short peaks are so high you can hear the intermod in your ears and your peak meters go through the roof. Only happens with the very best choirs.

I recommend anyone involved in audio to go and make some recordings yourself. You don't need the very best mikes & supa equipment though it is far easier to get really good stuff this millenium. But your outlook on reproduced sound will change.
Richard, I know where you're going with this, and this is the classic difference between the subjective impression of the loudness vs. what the meter says. And I've been down this road many, many times.

There are 2 factors at work here: if there are genuine short term high intensity peaks in the actual sound, well above 120dB say, then a choice has to be made with the recording mechanism: either the true peak levels have to be recorded correctly, which means that the average level is well down, the recording played back will sound incredibly soft, so you'll wind up the volume so it sounds "right", and then, yes, that peak will be clipped; or, as in nearly every case, this short term transient will be automatically compressed by some element of the recording chain - every CD you buy will be "victim" of this "manipulation".

And the other factor is that the subjective intensity of the sound, which is what you're talking about experiencing when standing in front of the real thing, is a characteristic of the level of distortion of the sound. The subjective "loudness" of my systems vary dramatically, depending on the state of tune; the volume control setting doesn't change, but the perceived intensity, the ability of the sound to seem to rip through my skull, in a nice way, will alter depending upon just about everything. I regularly do things like standing 6 feet away from a big band going full bore, bypassing the stupid PA nonsense, to calibrate the sensation of that intensity of sound ...

Frank
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Old 7th November 2012, 12:59 AM   #29032
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Originally Posted by kgrlee View Post
Frank, you can easily check this by recording your own upright with a good pianist ...We are only checking for clipping which you can extrapolate to a 1000W amp.
It's not the average levels but the peak levels which are a problem. I used to sing with a choir that often sat in front of the brass section so I know how loud this gets.
May i confirm ? Recording a piano is a nightmare and need *careful* limitation/compression for future realistic reproduction in a medium home system.

One of the best piano recordings i know is the Don Pullen "Sacred common ground ". There is one tune i can't afford without tears.
I was told that he was just back in the studio from the hospital where he was just tough he had an incurable lymphoma.
He sat at the piano and improvised. Engineers have been running the tape and it gave this piece, full of grief, anger, fear, and desperate love of life.
I don't know if the story is true.
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Old 7th November 2012, 01:07 AM   #29033
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Originally Posted by Esperado View Post
May i confirm ? Recording a piano is a nightmare and need *careful* limitation/compression for future realistic reproduction in a medium home system.

One of the best piano recordings i know is the Don Pullen "Sacred common ground ". There is one tune i can't afford without tears.
I was told that he was just back in the studio from the hospital where he was just tough he had an incurable lymphoma.
He sat at the piano and improvised. Engineers have been running the tape and it gave this piece, full of grief, anger, fear, and desperate love of life.
I don't know if the story is true.
I need to augment my Pullen collection a good deal. I do like Random Thoughts quite a bit.
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Old 7th November 2012, 01:14 AM   #29034
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This tune is "Coomon ground, the second one on the CD. I don't enjoy too much the other tunes of this album, a little destabilized with this American Indian Music.
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Old 7th November 2012, 01:40 AM   #29035
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Like many others I am intrigued by our perception of sound. This thread does cover a very diverse range of subjects so may be this post is not toooooooo far off topic. But while we are looking at this area has anyone got experience of the reaction of other species to reproduced sound?
I mention this because John Linsley Hood who was both a competent designer and someone who appreciated music, records some anecdotal accounts about his Siamese cat: Fingal. Apparently the cat noticed changes to equipment, reacted adversely to some modifications to circuitry and disapproved strongly of one particular amp'.
I recall he mentioned this in at least one of his published magazine articles but a more accessible reference that some members will own is his book "Valve and Transistor Amplifiers", page 195.
Any others had domestic pets express their views on equipment?

It crossed my mind that it is possible that they may be more "objective" their response. They would be free of preconceived ideas and commercial interests but how their opinions could be reliably documented would require some additional thought.........

Btw Scott we in Oz appreciate the new avatar.
Cheers, Jonathan
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Last edited by Jonathan Bright; 7th November 2012 at 01:44 AM.
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Old 7th November 2012, 02:24 AM   #29036
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Johnathan,
could it be that our animals are listening to what we would call out of band frequencies? I think perhaps they are hearing the high frequency hash that most upper frequencies will show any time you get over 20Khz if you are lucky. So if a titanium dome or a compression driver has increased output in this range and it isn't exactly musical in nature our dogs and cats are hearing that. Listener fatigue from the dog.......
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Old 7th November 2012, 02:42 AM   #29037
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Originally Posted by fas42 View Post
Huhh?? Speakers are speakers, amplifiers are amplifiers; actives are only so because the length of speaker cable is very short, and the output stage doesn't have to pump unused amps into the crossover. As I said in another post, electrically every system should be considered as a totally integrated mechanism; actives win over passives because the engineering between the amps and the speaker drivers is better sorted out ...
No. I mean that for active speakers they publish max SPL on 1M that the amp/speaker combination causes, without destruction and horrible distortions. For passive speakers they publish SPL on 1 M when input power is 1W. It is not about what wins, it is about how to interpret the numbers. They can't be compared, because active speaker can have for example a couple of 400W amps inside for 130 dB output, but each driver inside can have corresponding sensitivity that can be measured for 1W input.

Anatoliy
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Old 7th November 2012, 02:57 AM   #29038
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Originally Posted by Kindhornman View Post
Johnathan,
could it be that our animals are listening to what we would call out of band frequencies? I think perhaps they are hearing the high frequency hash that most upper frequencies will show any time you get over 20Khz if you are lucky. So if a titanium dome or a compression driver has increased output in this range and it isn't exactly musical in nature our dogs and cats are hearing that. Listener fatigue from the dog.......
My dogs sometimes react on sounds of other animals in movies, sometimes don't. But they always react on a door bell sound.
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Old 7th November 2012, 03:22 AM   #29039
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Originally Posted by Wavebourn View Post
No. I mean that for active speakers they publish max SPL on 1M that the amp/speaker combination causes, without destruction and horrible distortions. For passive speakers they publish SPL on 1 M when input power is 1W. It is not about what wins, it is about how to interpret the numbers. They can't be compared, because active speaker can have for example a couple of 400W amps inside for 130 dB output, but each driver inside can have corresponding sensitivity that can be measured for 1W input.

Anatoliy
Understood. Those max. SPL I would take as those corresponding to the onset of clipping of the amplifiers, because typically the monitors have decent protection from this sort of overloading. Interestingly, they also usually include the power of the built-in amps, so then it is relatively straightforward to determine the driver sensitivity.

Frank
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Old 7th November 2012, 04:50 AM   #29040
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No, still not happy ... remember I only was working with a single speaker, the stereo pairing adds 6dB in the "sweet spot", so now that 256W/channel is pumping 118 + 6 = 124dB into your skull at 1 metre. Okay, back off to listening distance used by many, 2 meteres, roughly lose 6dB, still around 118dB. And we haven't taken into account additive effects of room reflections ...

Now, I know how many systems appear to lack grunt, but IME this is all about the quality of the sound ... lack of distortion. All my experience has shown me that a nominally low powered system working correctly creates the subjective impression of high impact, dynamic reproduction.

Frank
It doesnt work for me. And, my speakers are not 94db or more effec. So back down on that number by several db and crank the power back up. I listen further away than 6 feet..... more like double that. I find that 250W is a minimum number. The point is that many have much less capability in speakers and power to drive them to reach a semblance of reality -- including low distortion and dynamic range. Thx-RNM
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