Excellent point about conductors. First of all, they don't stand anywhere near where the audience sits, they hear something entirely different. It's much closer to what you'd hear on a recording. This is because they are much closer to the musicians. One difference between a recording and what the audience hears is that the microphones are of necessity placed much closer to the instruments and they are directional selectively picking up most of their sound from the direction of the instruments. Human ears are pointed sideways. If one ear is turned towards the musicians, the other is turned away from them.
One problem for concert hall designers is to produce sound that allows the musicians to hear each other. This may not seem like a problem to the audience but for a 100 piece symphony orchestra to play at its best, this is an important criteira. The acoustics on the performing stage are critical to that.
One problem for hearing concert halls or doing anything else in the USSR was that traveling was very restricted and difficult. Also, once you got out of the major cities, unless you spoke Russian just managing to communicate could be a prolem. Interviewing people, arranging to measure different halls for pourposes of Beranek's paper could have been a problem.
The best musicians always try to understand the acoustics of the venue where they perform. They know that the effect of acoustics can greatly enhance or detract from the experience the audience has listening and can affect their reputations. Peter Nero said in an interview on NPR several years ago that he'd arrive at a performance venue several hours before a concert and he and his assistants would move his piano around on the stage looking for "the sweet spot" where it sounded best in the audience area. Sound familiar?
Many factors including the tempo at which music is best played can be affected by the way the acoustics of venue. Too fast for the reverberation time and the sound becomes a blur, the notes run into each other as direct sound and early arrivals from one note coincide in time with late reflections from previous notes. Too slow and the notes become discontinuous, a stacatto like effect.
One effect common in music witten in the romantic era is the grand pause which when correctly played adds greatly to the music's dramatic effect. The orchestra plays to an enormous crecendo and then suddenly stops. The conductor waits for just the precise moment when the reverberation dies out before the next note is played. This is one of the best examples of the principle in music called tension and release. In recordings, this effect is completely lost or barely exists at all due to lack of reverberation compared to a live performance. To a lesser degree, there is a pause at the end of each musical phrase as though the musicians take a brief moment to take a breath. How long this lasts or should last will depend on the acoustics of the venue. Understanding how to best "work the room" is not something musicians usually learn quickly. This is why orchestras are said to sound their best playing in their home city at the concert hall they are most familiar with.
The general trend has been to create halls which have shorter RTs than say about 100 to 150 years ago. Whether new or remodeled they are usually designed for mid frequency RTs of 1.8 to 2.0 seconds. In bygone eras it was frequent that they were at 2.5 to 3.5 seconds. This shorter time lends itself to faster playing and performances of more modern compositions. For opera houses it's often 1.4 to 1.6 seconds. For cathedrals it can be as high as 5.0 to 8.0 seconds.
As in a divorce, there are always two sides to every story, your's and $***head's
According to Beranek's version of what happened at what was originally known as Philharminic Hall at Lincoln Center for the Performing Arts, the managers demanded a hall which would accomodate an audience of at least 2900. Beranek claimed that this was too large for good acoustics given the space requirements. (Buidling codes will dictate not only how much seating space is required but other spaces such as egress aisles for a given occupancy. NYC undoubtedly had its own code which was probably particularly tough.) Anyway, there was a dispute. The managers controlled the money and as the golden rule has it, he who has the gold makes the rule. This is when Beranek should have thrown in the towel and quit while he was ahead. Instead, possibly dazzled by the prestige designing it he expected would confer on him, he built what was generally conceded to be an abortion of a hall from the get-go. Eventually he was fired and spent the rest of his life explaining his side of it. After the initial fiasco, money was poured into it by patrons of the arts over and over again to try to salvage and rebuild it into something at least passable. Probably at one time or another most prominent acoustic architects took a crack at it. I think Cyril Harris was among those who gave it a try. In fact so much money was donated, some musicians began to call it philanthropic hall. I first heard it when I was in junior high school or high school on a school trip. As I recall, we entered the balcony area and sat listening to Leopold Stokowski rehearsing the NY Philharmonic. I could distinctly hear the reflection of the trumpet off the left procenium arch. That's when I knew there was something wrong with it but who was I to criticize, I was only about 14 or 15 years old. Beranek says the RT is too long. In my edition of Sam's Audio Engineer's handbook, the value of R should be between 1 and 10. At Avery Fisher hall, it's close to 1. At Boston Symphony hall it's nearly 10. (R is the relationship between reflections from 0 to 50 ms and reflections between 50 and 400 ms.)
The use of wood according to Beranek soaks up bass if it is less than 2 1/2 inches thick. It is usually therefore not a good material for use in concert hall construction contrary to popular notions. He said he heard one in Norway built of wood that was thick enough, the sponsor being a lumber company and it is very good. The wainscotting on the performing stage in Boston Symphony Hall is a concession to this popular misconception but isn't sufficient in quantity evidently to badly adversely affect overall acoustics.
The sound in the round arrangement where the audience surrounds the performers is an interesting notion but probably not a very good idea. Beranek claims he heard a performance of the Brahms second piano concerto at the famous one in Berlin. He was sitting behind the pianist and because the lid was propped open, he heard nothing coming from the piano above 2 khz.
Natural Highs.....
Years ago I was fortunate to be in a local (central Perth) cathedral changing some PAR types lights way up high, and in came one of the church organists to practice his rendition of Toccata El Fughe.
What a pleasure hearing the same piece over and over whilst there were no congregation/audience noises to distract from the instrument and hall sounds.
We have all heard this composition reproduced, but that ain't no comparison to the real thing.
Even better is hearing my mother play her Jacobus Steiner 1671 Lions head (Strad precuresor and similarly regarded) violin in familiar surroundings.
"Today Stainer is regarded as the greatest violin maker active outside of Italy. Until the end of the 18th century he was ranked above even the most illustrious representatives of Cremonna. Both Bach and Mozart composed using Stainer Violins"
Eric.
Years ago I was fortunate to be in a local (central Perth) cathedral changing some PAR types lights way up high, and in came one of the church organists to practice his rendition of Toccata El Fughe.
What a pleasure hearing the same piece over and over whilst there were no congregation/audience noises to distract from the instrument and hall sounds.
We have all heard this composition reproduced, but that ain't no comparison to the real thing.
Even better is hearing my mother play her Jacobus Steiner 1671 Lions head (Strad precuresor and similarly regarded) violin in familiar surroundings.
"Today Stainer is regarded as the greatest violin maker active outside of Italy. Until the end of the 18th century he was ranked above even the most illustrious representatives of Cremonna. Both Bach and Mozart composed using Stainer Violins"
Eric.
Oh the short memories.
When BBN started to design what was to become Avery Fisher hall, there was a lot of press. The used scale models, pressurized to keep scale propagation speeds and played recordings, using miniature transducers to produce and record sounds. From this they developed their designs. Great concern was placed not only on what makes a hall sound good, but also to keep noise out.
This was really the start of modern calculated design rather than the this is what I built before and we can change it slightly school.
Yes it was a disaster for many reasons. Of course Carnegie Hall was not well received at first. It only got it's famous sound when a producer cut a hole above the stage and coupled the attic space to the rest of the hall. (Yes a really true story).
There is a really good reason why all of the old halls are great halls. They tore down the bad ones after a while. (Or Scott's dad and his comrades flattened them. Never give a critic a 2 ton bomb!)
These days it is BBN alumnus Carl Rosenberg and Ioana Pieleanu who seem to be doing performing halls. A bit more than a year ago I did a project with Acentech the current firm name. It was an absolute pleasure to see all of the classic construction techniques. Solid construction, not a right angle in the place, Wood polynomial diffusers with heavy movable curtains and fixed and movable reflectors.
They spent 2 days making measurements and checking the results versus the predictions. This included having performances by choir, orchestra and others. Everyone was really too busy with check out to spend much time chatting. The biggest problem was the power transformer for the sound system had enough hum that they missed the design NC goal. So a wall had to be added.
Over the years I have worked with four of the world class firms doing concert acoustics. I was going to say three but Sam might actually make it.
What used to be art is now reasonably well understood and the art comes in refining the flavor of what you want to hear.
So if you have the money you can pick who you want to do the design and know what to expect.
ES
When BBN started to design what was to become Avery Fisher hall, there was a lot of press. The used scale models, pressurized to keep scale propagation speeds and played recordings, using miniature transducers to produce and record sounds. From this they developed their designs. Great concern was placed not only on what makes a hall sound good, but also to keep noise out.
This was really the start of modern calculated design rather than the this is what I built before and we can change it slightly school.
Yes it was a disaster for many reasons. Of course Carnegie Hall was not well received at first. It only got it's famous sound when a producer cut a hole above the stage and coupled the attic space to the rest of the hall. (Yes a really true story).
There is a really good reason why all of the old halls are great halls. They tore down the bad ones after a while. (Or Scott's dad and his comrades flattened them. Never give a critic a 2 ton bomb!)
These days it is BBN alumnus Carl Rosenberg and Ioana Pieleanu who seem to be doing performing halls. A bit more than a year ago I did a project with Acentech the current firm name. It was an absolute pleasure to see all of the classic construction techniques. Solid construction, not a right angle in the place, Wood polynomial diffusers with heavy movable curtains and fixed and movable reflectors.
They spent 2 days making measurements and checking the results versus the predictions. This included having performances by choir, orchestra and others. Everyone was really too busy with check out to spend much time chatting. The biggest problem was the power transformer for the sound system had enough hum that they missed the design NC goal. So a wall had to be added.
Over the years I have worked with four of the world class firms doing concert acoustics. I was going to say three but Sam might actually make it.
What used to be art is now reasonably well understood and the art comes in refining the flavor of what you want to hear.
So if you have the money you can pick who you want to do the design and know what to expect.
ES
??? The speed of sound in air varies as temperature not pressure. I can just see the doll house violins and microphones.
>For an ideal gas the speed of sound depends only on the temperature and
is independent of gas pressure.<
The idea is the same as using water at an appropriate speed for scale aircraft models.
You want the model to map 1KHz, but you have a 10:1 model, then you either have to use 10KHz or pressurise the model.
Wrinkle
there is control of reverb time at each frequency and initial time delay from first sound to the beginning of the reverberation time.
i remember a dome project i worked on. the opinion of the owners was: regardless of the sound, the dome will sell out.
Gee,
My favorite dome project was profitable and educational. They had a budget of 250K. Cost was around 90. I knew they would throw out too low a price so I quoted 225. Low guy at 85 was thrown out, the brand name folks they wanted were 750, so I got it.
Everything worked well except the woofers, rolled like a rock at 300. No bass, classic two zero curve. Checked everything in the electronic circuits, power was there. Blown speakers? Hit the down button on the speaker cluster winch, music was still playing. As it dropped 15 feet, all the low end showed up! Raise the cluster... gone. Down... back on! A slight realignment of the mids and highs allowed for the new operating position.
I placed a piece of tape on one of the wire ropes to clearly mark the correct operating height. Worked well until the house electricians got tired of climbing to the hoist platform and put on a remote control so they could operate the winch from the control room. "Yeah that looks about the same."
So there were two important lessons to be learned.
I don't follow you, your only choice with air is 10kHz pressurizing to 10ATM will not change the speed of sound 10X. Same is true of water, sonar?
MJL21193 help, it's back.
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They may have been pressure for absorption coefficients to scale the material, or my recall may be foggy.
Yes everyone knows that the velocity of propagation is almost a constant for a gas. It is explained that the difference when measured at different altitudes is due to temperature (10 degrees F is about a 1% change). Of course PV=NRT has nothing to do with it? Then there is the difference between compression and rarefaction.
My recall is that they also had to change the pressure to get all parts of the scaling right.
And PV=nRT**gamma, and gamma is not one, but that effect is quite small over the range of pressures we are dealing with here.
Also Scott
What is the bit about "MJL21193 help, it's back." to do with?
Wrinkle
BBC RD 1970/13: Acoustic scaling: General outline. H.D. Harwood, A.N. Burd
The reason to enclose the model would be to ensure a very low %RH can be maintained locally to avoid excess in-air losses at the very high frequencies used - the Beeb used a zeolite trap in the setup. I can't see that high pressures per se help in any way.
The reason to enclose the model would be to ensure a very low %RH can be maintained locally to avoid excess in-air losses at the very high frequencies used - the Beeb used a zeolite trap in the setup. I can't see that high pressures per se help in any way.
I think they use gas other than air. Not pressure, temp, or etc.
Another technique is light beams to eyeball bounce angles.
I worked on Roy Thomson Hall in Toronto, a BBN product around 1980. Turned out to be a very poor sound.
Funny, I sat with the development team during the first orchestra rehearsals. I said to the construction manager, "Hey, this is just the way I like it, really dead." Boy, did he give me a dirty look.
At the staff and friends open-house concert before opening, the acoustician did some testing with a full house (starter pistol, etc.). Tuning the reflector clouds is fine-tuning for the sound the players hear versus shared with the audience.
My end of things involves "user friendly" issues such as seating, womens toilets, access, etc. Some of these halls are interesting for seating. Check out the aisles!
Another technique is light beams to eyeball bounce angles.
I worked on Roy Thomson Hall in Toronto, a BBN product around 1980. Turned out to be a very poor sound.
Funny, I sat with the development team during the first orchestra rehearsals. I said to the construction manager, "Hey, this is just the way I like it, really dead." Boy, did he give me a dirty look.
At the staff and friends open-house concert before opening, the acoustician did some testing with a full house (starter pistol, etc.). Tuning the reflector clouds is fine-tuning for the sound the players hear versus shared with the audience.
My end of things involves "user friendly" issues such as seating, womens toilets, access, etc. Some of these halls are interesting for seating. Check out the aisles!
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An old thread that should be let lie, it all ended in a big laugh let's keep it that way.
Gamma IIRC is due to the degrees of freedom for the gas molecules. Degrees of freedom is the neatest fudge factor that I have come across.
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