How close to the real thing?


Recently a friend of mine heard a Chopin concert in a Baptist church. I had told him that I had gone out to RMAF this year and heard some of the latest gear. His comment was that he thinks the best audio systems are only about 5% close to the real thing, especially the sound of a piano, though he admitted he hasn't heard the best of the latest equipment.

That got me thinking as I have been going to the BSO a lot this fall and comparing the sound of my system to live orchestral music. It's hard to put a hard percentage on this kind of thing, but I think the best systems capture a lot more than just 5% of the sound of live music.

What do you think? Are we making progress and how close are we?
peterayer
some recordings, I do get a soundstage extended a couple of feet past my speakers in width, But never can I take an orchestra that its natural width would be say 25 feet and get my system to reproduce this. Within these limits, I get Outstanding instrument placement on width as well as depth. If anyone has any ideas on how to improve...
I'm all ears.
Timlub (Threads | Answers | This Thread)

Try a different DAC,or CD player.I tried one DAC that made my soundstage that can go extremely wide at times,shrink down to about 3-5 feet.A friends budget(Teac?)CD player made his 8-10 foot speaker width sound like 50 feet apart.Sounded good on some music,like a reverb on other types of music, The equipment specs don't seem to mean much here.
Hi Frank, Well,I've read all that you've had to say and am sorry to say that I just don't buy it. Yes,my speakers absolutely dissapear. I don't want to discount your opinion, but I've been around this game for a long long time. I have found a long time ago, even when I started in this business in 1979, That measurable distortion is so far below our hearing that it was unconceivable to hear. Most tube amps measure higher distortion than solid state, yet tube amps nearly always have better staging than solid state. I don't know what type of distortion that you are quoting, i.m, thd?
What equipment today has distortion ratings that are a concern?
Timlub, glad to hear how you're doing! If anyone here could see my current setup they would laugh hilariously, it looks a mess... Speakers roughly 2 ft from back wall, about 6 ft apart.

What I learned to concentrate on, is eliminating all, and I mean ALL, unpleasant distortion from the system, and this can be very, very difficult to do. Everything matters, as they say, and if you don't fix everything then you are making it very hard to get it to happen for yourself.

How low should the distortion be? A simple test, when the system is working flat out on a "difficult", or any recording, is that a speaker completely disappears. That is, standing a foot away directly in front of one (left or right) speaker and in line with the tweeter (or high end reproducer) your ear/brain cannot pick that the sound is coming from the drivers. "Believe it or not ..." as I think someone once said ... :-)

Why this can happen is that the ear/brain compresses the loud sound, rather than the system. This is what happens naturally; how else can a player in an orchestra tolerate the sound level around him if this didn't happen ...

Frank
Hi Frank,
My back wall also dissapears. I get a soundstage from my speakers to maybe 10ft behind my speakers and they are 6.5 ft from my back wall. My speakers are 106 inches apart and on some recordings, I do get a soundstage extended a couple of feet past my speakers in width, But never can I take an orchestra that its natural width would be say 25 feet and get my system to reproduce this. Within these limits, I get Outstanding instrument placement on width as well as depth. If anyone has any ideas on how to improve...
I'm all ears.
Timlub, as notes of interest I have had almost the same number of years as yourself wrestling with this bizarre and at times excrutiatingly frustrating "addiction", and also my room is almost a perfect size match to yours.

For me, when the system is working correctly, i.e., low levels of distortion, the auditory experience is that the end wall completely dissolves and the room becomes attached to the location where the recording was made, the "window" experience, I guess. If a large scale orchestral, then exactly if one were sitting in a private stall in the concert hall. It is no longer that of a musical event in a room, the sensation is that the whole house has somehow been transported and is sitting next to where the musical event is happening, and is a mere extension to the "soundstage". Very hard to get to happen, but very much worth it!

Frank
Any way that you look at it, High power matched with high effiency speakers will produce dynamics. And back to the ops original question, Dynamics go along way toward making a convincing presentation.
and Fas42, I have found on large scale music that room size does matter in reproducing that large sound stage. Maybe its just me not figuring out in 30 years how to set up a system in a smaller room, but I definately get a wider more natural presentation on large scale music in a larger room. Granted, the largest room I have experience in is about 20x30 ft (6.25x9.25 meters), but on large scale music, I have definately experienced a larger sound stage. My current room is 14.5x22 ft and it does a wonderful job with small scale recordings, but I haven't been able to duplicate some of the large scale stuff that I have heard in the past with the same recordings.
Cone mass & power also matter in larger rooms. If I understood what Weseixas was saying?
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Pubul57, it gets tricky talking about different powered versions of particular amp types, it's almost a how long is a piece of string conversation!

Theoretically the higher powered amp SHOULD be better because its power supply needs to be bigger, and it is working more within its limits. Unfortunately, manufacturers change a whole lot of things going for bigger power, and quite often these are backwards steps in terms of maintaining quality. For example, a small amp may be fully hard wired with very direct connection paths. The bigger unit is made up of modules, with wiring harnesses with push on connectors for ease of manufacture, and bang, there goes your quality in one hit! In other words, the actual quality of the engineering of the particular component is far, far more important that the nominal power rating.

A 60 watt amp and 89dB sensitive speaker will do a very, very nice job IF everything is optimised, and the amp does produce genuinely clean 60 watts -- class A is a relatively easy engineering way to do this, of course.

Frank
Weseixas, I'm sorry but my figures correlate very closely with Atmasphere, 96 versus 98 sensitivity, 120 versus 140 good watts, my sound level of 117dB at 1m, his of 110 at 3m. Check out a text book, you lose 6db per doubling of distance -- from 1m to 2m down 6dB, from 2m to 4m (a doubling) down another 6dB, total 12dB. Remember, a 3dB difference is only just detectable by ear.

I also pointed out previously that the 10 to 20 times power is completely unnecessary IF the system is not distorting. I thus agree, that if the system is poorly engineered then you would need a very large "safety" margin, to compensate for the inadequacies of the setup.

Finally, the room size has nothing to do with it. Having personally experienced what is possible with a nominally mediocre setup, which has been tweaked in every which way, in a very nondescript normal room, I say that with total confidence.

Frank
Shadorne, your Sheffield labs drum track test would be a very good one, but as regards the sound meter reading you refer to a "SUSTAINED 108 to 112 db" value, which would not be the same as the the actual peak dB reading. From Wikipedia: "'Peak sound pressure level' should not be confused with 'MAX sound pressure level'. 'Max sound pressure level' is simply the highest RMS reading a conventional sound level meter gives over a stated period for a given time-weighting (S, F, or I) and can be many decibel less than the peak value".

I would suggest that that the peak dB level in the test you describing would be well over 120dB at 1 meter -- I don't want to destroy the bass driver's suspension!!

Frank
Hello Pubul57,

Your speaker would be the limiting factor in producing the sound we are alluding to, that aside i do believe your system would benefit tremendously from an increase in power...

Maybe one day Ralph will allow you an in home demo of a pr of MA3, just before he delivers them to the Prince of Persia, you will for sure hear the difference between a "likkle" one and an Atmasphere Big 'un...

:)

Regards,
Ohhh, sorry guys , almost forgot, you also need a big listening room, you won't be fooling anyone in a small listening space.

THE ROOM IS UBER IMPORTANT !!!!!!!!!!!!!!!!
Frank, do you think lower power versions of the same basic amp circuits tend to have inherently less distortion than more power? I don't have super sensitive speakers (89db), listen acoustic jazz (trio to octets) 90% of the time, and I suppose I just don't listen to music that loud (I don't think)and there just seems to be something to the notion of using the lowest power amp that is sufficient to drive your speakers will sound better, not louder, than a higher powered version of the same basic amp (think Pass XA60 versus XA100)- and they key being "sufficient" power has to factor in speakers, room, and average volume levels. It is why I asked about the high power amp / high efficiency paradigm mentioned - it might very well do the macrodynamic thing well, but I somehow something would be lost going that route, at least to the way I listen to music - I suppose the fact that I have a smallish two-way (Merlin VSMs) and don't listen to alot of orchestral music on large multi-driver speakers also has alot to do with it. I find my 60 watt Atma-spehre M60s to play as loud as I could ever want, with huge space and purity, and microdynamics as described, and somehow feel a 1000 watt amps might destroy all that. That approach might be closer to the real thing in some ways, but not in others.
Hello Frank,

Atmasphere is not going well over 110db and you stated 117 db, the power increase to do so would exceed his setup substantially. Also i did state the correct drop with increase in distance, you had left out such in your original calculations, so I'm not sure what you are alluding to when correcting your calculations.

In order to achieve realistic percussive energy and size of live music will require a minimum of 10 to as high as 20 times your RMS output to even come close to the dynamic pulls associated with live symphony music or the sound of a grand piano in the room example as previously discussed.

No Sota system can even be thought of with only 120w/ch IMO, lots of speaker radiating area and Power would be a necessity, to say the very least.
Hello frank ,

you stated 117 and 96 , those numbers are completely different from Atmasphere's.
Pubul57, it is quite remarkable the enormous number of terms used to describe system sound, which ultimately are only ways of categorising the types of distortion, or lack of it, being generated. To me, micro dynamics simply means, as in real life listening to everyday sound, that you can hear the fine details of a subtle, low level sound occurring at the same time as louder background sound. For example, jingling of change in your hand while a heavy truck thunders by. Likewise, macro means the rich, bass rumbling of that truck passing is fully sensed, or the crescendo of an orchestral climax seems to wash over you with tremendous force, with no sense of discomfort.

It's all about distortion, the amp that sounds better to you is producing less of the distortion, at that particular moment, that you're sensitive to.

Frank
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Weseixas, in your last response to Atmasphere you acknowledge that 110dB peak is easily attainable at the listening position, which is exactly what my figures were pointing to. My 117dB number was peak, not DIN, average, RMS or anything else. By the way, the level drops 6dB per doubling of distance, not per metre, so 117dB at 1m, 111 at 2m, 105 at 4m. And, that is only one speaker, the stereo setup nominally adds 6dB to those figures, plus the listening space normally is not open; further back, reflections from side and back walls complicate any simple maths.

The end result, as Atmasphere points out, is that well over 110dB PEAK sound at 3m with the right combination of hifi gear is easy to get. To now get that in perspective, a study of the sound levels experienced by members of an orchestra, not the audience(!), playing "heavy" music only momentarily went a db or so over 120dB peak in the worst possible case. Many audio people would suggest orchestral recordings are the hardest to get "right", but from the point of view of the dynamic capabilities of the system it should be no problem at all.

So, why don't orchestral recordings typically do it (sound real)? Again, as I mentioned earlier, the answer is distortion -- the two common ways of reproducing sound both have failings.

The audiophile way: make sure at low levels that the sound is "pure", that is, low levels of unpleasant distortion, but run out of grunt and it starts to compress and fall apart as the volume increases.

The pro way: plenty of grunt from the word go, but the effort has not sufficiently gone into eliminating the subtle mechanisms that inject relatively low level but nasty distortion into the sound, at any volume -- the too frequent PA setup, BIG sound hammering at you, impossible to tolerate for anything but a short period.

(Which, by the way, is why I shudder at the thought of seeing a live show these days: once or twice in my experience the sound people knew what to do, but, as an example, for me Phantom of the Opera at the premier city production was a nightmare, at the end of the evening my ears felt like they had been bludgeoned to death!)

But, there is a third way, as some people have discovered: put together efficient speakers and reasonably powered, high performance amplifiers with a decent level of care and fastidiousness and you should have an excellent chance of getting close to the "real thing".

And, for the people who claim it is all about room treatments and precise positioning of the speakers, in my experience this is wrong too. The ear brain combination is extremely capable and tolerant; if you give your head half a chance by supplying a sufficient amount of CLEAN sound information, then it can decipher what is going on and generate the experience of "being there". What the treatment and positioning thing helps to do, I believe, is to reduce the obviousness and impact of the distortion components in the sound, a sophisticated equivalent to specialised ear plugs.

Finally, I believe firmly in the LIAR (Listening In Another Room) test -- if the system fails this then it certainly won't sound like the "real thing" anywhere ...

Frank
Hello Atmasphere,

I was referring to "Din" not peak db when describing ear splitting. If you are using the typical listening distance of 3M it would require 156 watts to do 110 db, very plausible you are able to do so with 140 watts when factoring headroom.

regards,

Speaking of dynamics, can someone clarify micro (resolution an speed?) versus macro (grunt and drive?) dynamics? I was also thinking about the issue of high power amps, for some reason, lower power amps usually sound better to me, a pair of tubes per side amp seems to sound better to me than 4 tube per side versions of the same basic circuit, though the wattage is lower, must be some attribute having noting to do with SPLs.
One guy's 95% is another guy's 5%.

I agree with Peterayer about this. I tried to make the same point in my post on 11/27.

FWIW, I think that the recent discussion about the SPLs of real musical events vs. recorded ones illustrates how audiophiles use different standards for judging how real a system sounds. Consider the following two standards:

1. Maximum undistorted SPL.
2. Headroom.

It seems that several posters use maximum undistorted SPL as a standard (among others presumably) for judging how real a system sounds. For some kinds of music, like rock, that seems totally appropriate.

But, to me, maximum undistorted SPL is a less significant standard than headroom, understood as the DIFFERENCE between the average level and the maximum level. To me, sufficient headroom during playback goes a long way toward making a recorded musical event sound real, even if the system’s maximum undistorted SPL is rather modest. This is partly a consequence of the kind of music I tend to listen to. It is also a consequence of the mental “standards” I use for judging how real a system sounds.

Of course, headroom is largely determined by the recording (both its inherent informational limits and the elective use of compression), but it seems to me that some systems do a better job with dynamic contrasts than others, and that that capability is related to, but not identical with, maximum undistorted SPL.

Both maximum SPL and headroom fall under the general category of "dynamics." But they can have different roles in a listener's perception of how real a system sounds. As an OBJECTIVE standard, maximum undistorted SPL is a critical measure of comparison between real musical events and recorded ones. But, as a SUBJECTIVE standard, it is somewhat less relevant, at least for some listeners.

Bryon
I can hit 110 db at my listening chair with ease, and the system does not strain to do it (me speakers are 98 db and the amplifiers have 140 watts in class A). In fact at that volume it sounds quite relaxed- you have no idea its making that sound pressure until you try to talk to someone sitting beside you.

So its not 'ear-splitting' bit OTOH the equipment was built specifically to not distort the odd harmonics. That type of distortion (and IM) leads to 'ear-splitting' behaviors.
Hello Shadorne,

I'm not using "ear splitting" as a pejorative and I have heard the studio "monitors" listed and have designed a few myself in the past, sometimes to replace, sometimes to assist those listed, so i'm aware of "loud and clean" and any system producing a continuous Din of over 117 db is ear splitting to me and i will no longer expose myself to such.

A few of those studios would record SPL's in the 138 dB + range(some could shake the console) I can bet a lot of those guys probably don't hear much today... :)

Live instrument grow with a size and power that is unique to there reproduction, to reproduce this growth will require power, lots of it and most if not all speakers will benefit from this power reserve.

Regards,
"You will be surprised that tremendous SPL is not "ear splitting" when it is clean, undistorted and dynamic."

I have invested a lot of time, effort and money addressing these aspects of good sound in my home system.

My conclusion is that it can be practically achieved but is not likely to happen by chance and does not come cheap.
Hello frank,

You should deduct the 6db drop for every 1M from the speaker, since typical listening distance is about 3M that means your 96db would translate to 84db at the listening position with 1 watt, it would take a lot more than 120/ch to reach your goal of 117db and typically you want to have a min of 5 times above the required rms power, sometimes more due to phase shift.

It takes a lot more than what most think to reproduce the percussive energy of live sound (live instruments, not pa band sound) a min of 1K watt and up IMO if you are serious about it. It's not going to happen with 120/ch...

Regards,

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Weseixas, the term "ear splitting" immediately gives away the game -- what you are referring to here is a system that is overloading, lots of nasty system generated distortion hammering away at your ear drums, of course it sounds terrible! The other giveaway is "effortless power", so to translate:

System A: "alive", with size and effortless power - equals x dB's, by sound meter, with MINIMAL audible distortion.
System B: ear splitting SPL - equals precisely the same x dB's, by sound meter, with SIGNIFICANT levels of EXTREMELY unpleasant distortion injected.

As to an efficient speaker requiring lots of power, not true. Take a 96dB sensitive speaker, which is also an easy 8 ohm load (Klipsch again!), and an amplifier of capable of a clean 120 watts RMS. You get an extra 3dB volume for every doubling of 1 watt power, which means the speaker can produce 96 + (3 * 7) = 117dB at 1 metre. Considering you have two such speakers, then at a couple of metres you will have all the dynamics you need, PROVIDED the system is adding only low levels of distortion. Then, the clean "percussive energy" you speak of will be there in spades ...

Frank
I would have to disagree frank ......

Both would take considerable power, of course it's academic the less efficient would require more, but both would require such to sound alive.

Please don't mistake ear splitting SPL to be what is being discussed here. To sound "alive" does require a certain size and power, effortless power, completely different to ear splitting SPL Din, the system has to "grow" exponentially from top to bottom with a lot of percussive energy...
Recorded music through a sound system cannot approach live, "non amplified" musicianship. However, this is what we Audiogoners seek to achieve with our equipment purchases and room/system tweaks. I can easily get caught up into thinking how "live" my system sounds, and then I will go to a "live" venue. No mikes, no amps, no speakers. Just the musicians with their instruments, playing in the space. I then come back to reality. I do capture much greater than 5 % lol .
>I would think high efficency speakers with powerful amps >would make distortion and noise worse -- no?

No, systems typically either use powerful amps and low efficiency speakers, or low powered amps and high efficiency speakers. The outcome is roughly the same in each case, the setup runs out of puff at a certain point -- think of a small, light car with low capacity engine as compared with an SUV with a big V8, their maximum rate of acceleration would be roughly the same; any really decent performance vehicle is always about a light body propelled by a high powered engine. Of course, in this analogy, the combination has to be carefully matched and tuned to realise the potential performance and prevent problems, but this is just engineering!

The analogy follows into the audio world -- I once had fun in a large, noisy electicals store: hooked up a fairly mediocre but high wattage Japanese HT receiver to a good pair of Klipsch main speakers, wound up the volume, the sound was clean as a whistle and cut right through the store; a store bloke came running from the other side, yelling turn it down, not because it was distorting but because it was so dynamically loud ...

Frank
Mapman ,

The ohm's will not come close to reproducing the size or power of a grand being played in your house. A very good hi-fi system can sound like a piano, but will never fool you into believing it is a real piano, the size and power would never be the same..
I would think high efficency speakers with powerful amps would make distortion and noise worse -- no?
Interesting in this discussion is that virtually no mention is made of that nasty stuff, "distortion", by name. My experience is that ALL systems distort, some nicely, adding a soothing patina to the sound, but the majority inject varying amounts of relatively low level, edgy, unpleasant and irritating distortion which then overloads the ear and brain when you turn the volume up. I'm talking here of non-linear distortion, not frequency or phase response effects.

As mentioned, many musical instruments are naturally LOUD, but nasty, amusical, low level distortion is not part of unamplified sound. If you eliminate the majority of the unpleasant stuff from a system, which is typically very difficult to do, then even a very ordinary setup can sound hugely realistic.

One easier way to get there, as some know, is to use highly efficient speakers with powerful amplifiers; if the components are virtually idling when in normal use then you have a much better chance of keeping "bad" distortion at bay ...

Frank
Hi Peterayer,
I was really being a bit facetious. I can't imagine a more difficult task but to record something so loud and over such a huge area and make that come out anything like the real thing. I've read through this whole thing also and I agree with you brother. very subjective, lets just enjoy our tunes, Good Listening, Tim
Timlub,

A recording of that marching band would not sound like the real thing on my stereo system. That much is obvious. However, the fact that I can identify it as a marching band with certain specificity about types of instruments, orientation of players, type of venue etc leads me to the conclusion that it is better than 5% if you mean as it sounds from a seat high up in the stadium. If you mean how it sounds from one of the players points of view, no way. How real is it is very hard to say. At the very least it is dependent upon very subject perspectives, and there will never be agreement.

It's an interesting question, though. Suppose two people are listening to a piano over a car radio. One says, "You know, it's pretty damn amazing that we can be driving down the road in a car and recognize this music coming out of nowhere as a Mozart piano concerto. It really sounds quite good, and I'm loving it." The other one says, "No way. It sounds nothing like a real piano. Scale, timbre, dynamics, harmonics, they are all wrong. Switch it to talk radio."

After reading through this entire thread, I truly think either one of those guys could be right. One guy's 95% is another guy's 5%. I find the technology simply amazing and yet I realize that we still have a long way to go. To me it's not 95% or 5%. It is somewhere in that vast middle range. That's the best I can do to answer your question.
Shadorne,

Honestly, I've never measured SPL on a system. I take note of documented reference levels for common things like rock concerts, etc. With my current amps and OHM F5s, I have yet to push the volume to any level where distortion or clipping is heard because it is beyond any level that I care to listen at, and I do listen quite loud on occasion, close to rock concert levels I would estimate. You can't tell how loud it really is though until you try to talk and can't hear a thing.

Then again, my rooms is not big enough to accomodate a grand piano playing at its max either. So I'm going to wimp out and say my venue is my limiting factor for all practical purposes.
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Interesting, Timlub, the speakers that led me to believe I could come close to accurately reproducing piano were the original Legacy Focus (circa 1996). My previous A/D/S/ M15s could not. I also have to admit that the Legacy's proficiency on piano was a leap of faith for me, since the only way to buy Legacy speakers back then was factory direct. I actually talked with Dudleston at the time, asking him about piano reproduction, and after what I remember as a very long conversation he personally convinced me to place the order. I wasn't disappointed.

For you recording nerds, I used to use a Calrec Soundfield microphone (which I found used for $500 in a newspaper ad) and my absolutely mint Crown CX822 running Ampex 456 at 15ips. Modern digital recording sounds significantly better, but it's nowhere near as cool.
Thanks for the links, he quoted even higher for the marching band, 125db @ 100 ft away. With a starting point of 100db per instrument, it would take 256 players to make 124db @ the instruments or 1024 players to make 130db... I don't have any idea of how spl falls off in an open outside area, Lets just say that they did it... That is much easier and its over. Now Peterayer, can your system reproduce the marching band with better than 5% accuracy?
I cannot give a percent but Tidals come very very close when associated with good gear and good recordings in decent rooms.
Michigan Technological University 300 person pep band conductor.Not Michigan State,but correct quote from the man.125db at over 100 foot away.Take it for what its worth.
Link.[http://www.maestronet.com/forum/index.php?showtopic=321036]
Here it is.Post #11 "Bowler Hat"[http://www.maestronet.com/forum/index.php?showtopic=321036]
That was out of a talk forum like this one.Thats why I put the (?) there.[http://www.thumpertalk.com/forum/archive/index.php/t-476991.html]
Michigan State? Lets get the right mic's, get the perfect recording and play that one in your living room! Maybe I don't play at live levels.
Michigan State???? Thats a whole bunch of musicians playing as loud as they can, but 120db...@ 100 foot back??? 121db is our threshold of pain. 100 ft back?... it would have to be near 130db at the instruments.... I would have to question that one. In the past, I was a sanctioned IASCA judge(car stereo), I've owned my own store and have built several VERY loud systems, (160db) I remember being in a vehicle that hit 154. I wore ear plugs and sound deadening headphones over those. It moved so much air that it sucked the air out of your lungs. Ok another story. I just can't see non amplified instruments getting that loud in an open area. Never say never, I'm not questioning you, I'm sure that you read it, but I have to question the validity of the source. If you had 100 players of various instruments all playing @ 100 db, the total encompased sound pressure level would be 121db @ the instruments..... I have no idea of what that would be 100 feet away.
Timlub,Only the one link shows 110 db for the violin.There's a lot for over 100 db.Maybe the players/owners of those pricey pieces don't want to be bothered with measuring it. Just playing them might be their priority.Still,over 100 db can be bad.I think it was a Michigan State band director that said they get over 120db at 100 foot during practice(I think).
I was Googling Musicians and hearing loss,plus decibels for instruments,when I ran across that one.
Well Hifihvn, you just enlightened me, I didn't even consider the violin at the ear, nor am I experienced with any large scale concert type instruments.
and yes, we have headphones that allow some hearing. We do have a sound chamber that drummers can use(we tend to allow the drums on stage), it uses speakers as monitors and the drums are mic'd and sealed from the outside world, so the drums are completely by mix. Thanks for the info, i'll check it out. Tim
Hi Timlub,A lot of musicians have been aware of themselves being at risk for hearing loss.Schools of music teach them about this also.The headphones and plugs I was referring to,were the passive ones that they can hear what they need to,without amplified headphones,or plugs.It depend on the situation as you most likely know dealing with recording,or mixing for amplified music.A violin can reach 110 db at their ear.Wind instruments can get high also,plus a lot of others.It depends on the instruments too.But instruments used for concerts are the ones that are chosen for volume, along with their sound quality.There are some that say some of the lesser wanted instruments,may sound better, but just can't produce any volume,to qualify for a concert quality piece do to this.Some wear those plugs with holes in them(I think),that claim to let enough frequencies through for them to perform correctly.A couple of links for sound pressures.I'm guessing the music schools might have accurate info on this,plus Google.I like live music,we need it for our recordings,but we can do fairly good at home listening,for great enjoyment also.The last one may be conservative for db ratings in certain cases.Links.[http://www.hear-it.org/page.dsp?page=1662][http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm][http://www.gcaudio.com/resources/howtos/loudness.html]
"I completely agree that the wink link is the recording. Good Listening, Tim"

The recording being the weak link is where a good audiphile wants to be. That is one thing that is not in his/her control.