12. Listening to Music

Concert hall acoustics

Let’s imagine that you and a violin player have gone for a picnic in the countryside. If you both stop in the middle of a large, flat field and the violinist starts playing, you will find that the violin sounds a lot quieter than it does when she plays it in her living room at home.

In a room, the violin is louder because you are receiving the pressure ripples from each note several times over. You get the ripples which travel directly to your ears, plus the ones which were traveling away from you but have been turned back in your direction after bouncing off the walls, floor and ceiling. Apart from the increase in volume, this bouncing around also means that the sound is coming at you from all directions, so you feel bathed in music.

Out in the field, the violin sounds quieter because you are only receiving a double dose of the noise, once directly from the instrument, and one reflection off the ground. All the other sound travels in other directions, away from your ears.

So, the benefit of reflected sound is that we hear the music louder, and we also get the impression that we are surrounded by the music.

The size of the room and the materials that the walls, floor and ceiling are covered with determine the acoustic “liveliness” of the room you are in. You can check the “liveliness” of a room by clapping your hands and listening to how quickly or slowly the sound dies away. In a small room full of furniture and heavy curtains, the sound dies away almost immediately and the room is said to be acoustically “dead.” In a larger room with hard walls, the sound bounces back and forth off the walls several times before the sound dies away, and the room is described as “lively.” In a concert hall, it might take as long as a couple of seconds for this reverberation of your hand clap to die away. Musicians sound better in a “live” room than a “dead” one, which is why your singing sounds better when you are in the shower, surrounded by hard, tiled surfaces.

Although we enjoy the effect of sounds lasting longer because they are bouncing around the room, we want all the bounced sound from each note to overlap so that it reaches our ears as a single, long note. If the walls of the room are a long way away, the time between bounces will be too long and we won’t hear a single, extended note. We will hear the note, then a gap, then the note again—the dreaded echo. Concert hall designers live in the hope that their designs will give the audience lots of pleasant reverberation, but no echoes. This is a tricky balance, because both effects are caused by sound waves bouncing off the walls, ceiling and floor.

The difference between a concert hall and a living room is that, unless you are the Queen, the concert hall will be a lot bigger, and one of the more inescapable symptoms of a larger space is that the walls are farther away from each other. In a large room like this the reflected sound has to travel a long way, from the violin all the way over to the wall and back to your eardrum. The sound which comes directly from the instrument to your ear doesn’t take this detour, and therefore arrives first. So the two sounds are heard as separate events—one is an echo of the other.

In a small room, the reflected sound ripples and the direct sound all arrive at our ears at about the same time, because the round-trip to the wall and back is not much farther than the direct route. Although the direct sound arrives first, the reflected sound is hot on its heels. If the gap between their arrival is less than forty thousandths of a second, our hearing system just assumes it’s all part of the same sound. We only get a time difference above forty thousandths of a second if the round-trip taken by the reflected sound is more than 40 feet longer than the direct route from the violin to your eardrum. This could only happen in a very large space like a concert hall.

The acoustic engineers who design concert halls can reduce echo problems by putting absorbent material (which does not reflect sound very well) in places where the round-trip of the reflected sound would be a long one. They can also angle the walls so that the sound bounces around the room in the optimum way to give a “full of sound” feel without echoes.

Some concert halls have moveable or adjustable absorbing panels which can be arranged to suit different situations. For instance, you want less reflection for a public lecture or a comedian than you do for a concert. Panels like this can also be used to improve the acoustics of buildings with echo problems. One famous example of this is the ceiling of the Albert Hall in London. In this case, the curved, high ceiling used to reflect sound back down as an echo, until big, sound-absorbing “mushrooms” were installed.

Hi-fi, lo-fi or sci-fi? Home sound systems and recorded music

Microphones and speakers

Microphones and speakers are very similar devices—in fact, it wouldn’t take much effort to turn any microphone into a speaker or vice versa.

The illustration opposite shows us that a microphone consists of only two important bits:

1. A small paper or plastic cone which is light enough to tremble backward and forward when sound waves hit it.

2. A device for turning this backward-and-forward trembling into an electrical signal. The electrical signal goes up and down in exactly the same way as the paper cone moves backward and forward—as you can see in the illustration. It is clear therefore that if the cone is trembling because of the wave patterns of the music, then the electrical signal is also “trembling” in the same way—we have made an electrical “copy” of the music sound waves.

A microphone turns the backward-and-forward movement of a paper cone into an electrical signal. We can increase the power of this electrical signal by putting it through an amplifier—and use it to make the big paper cone in a loudspeaker move backward and forward—in order to reproduce the original music at a higher volume.

A speaker is just a microphone which is back to front—it has a device for turning an electrical signal into backward-and-forward trembling which is attached to a paper or plastic cone (which is usually bigger than the one in the microphone).

If we want to make a singer’s voice louder, we ask them to sing into a microphone. The electrical copy of the sound is then made and passed through an amplifier which makes it much more powerful (or amplified). We then use this powerful electrical copy to make the (generally larger) paper cone in the loudspeaker tremble backward and forward in the same way as the cone in the microphone did, and the music is reproduced at a louder volume—easy-peasy.

The recording and playback of music

Instead of using a microphone and amplifier to produce louder music immediately (as at a live concert), we can take the electrical signal and store it somewhere. The electrical wiggles can, for example, be used to drive a machine to cut a wiggly groove in a plastic or metal disk. Later on we can use a machine similar to the one that cut the groove to turn the mechanical wiggling back into an electrical signal—which we can put through an amplifier to push a speaker cone backward and forward so we can hear the music again (this is exactly how vinyl records work).

There are, of course, many other ways of storing the musical information produced by the microphone, including magnetic tape, which stores wiggles of magnetization, and silicon chip data storage or compact discs (CDs), where the wiggles are converted into a stream of digital data. Every technique uses the same principle: you take the sound and convert it into stored information and then, later, you decode the information to get the sound back.

Are vinyl records better than CDs?

Ever since CDs became freely available in the 1980s a fierce debate has raged about whether or not they provide a better copy of the music than the vinyl records they replaced. Much of this debate has centered on the difference between analog and digital technology—so I would like to describe what that difference is before I go any further.

THE ANALOG/DIGITAL DIFFERENCE

To keep this part of the discussion simple, I won’t talk directly about music. Instead, I will discuss the copying and reproduction of a visual image—so I can draw an example for you.

Let’s say we want to copy a wavy line by analog methods and by digital techniques.

Analog reproduction

An analog recording system simply takes a wiggly line and tries to make a direct copy of it by following its curves. The principle is similar to how a cyclist follows the line down the center of a winding country lane. The accuracy of the cyclist will be determined by how fast he is going, how sharp the curves are, and how long he spent in the pub at lunchtime.

A typical example of an analog recording would be for you to copy an image using tracing paper and a pencil. It’s quite easy to see how the accuracy of your trace would be improved by using exactly the right width of line and being extremely careful about it. There might be situations, however, where the line you are trying to copy wiggles to and fro too rapidly for you to follow it accurately.

Digital reproduction

Digital reproduction takes a completely different approach. The word “digital” means that a computer must reduce the task down to a series of “yes” or “no” statements. In this case the computer will divide up the page with the wiggly line on it into a lot of little squares. The computer will then point a camera at the image and ask itself “Is there a dark line in this square?” and do this for all the small squares, one at a time. The computer then stores all the “yes” and “no” answers. When the computer is asked to reproduce the image, it then prints a black square for every “yes” and a blank square for every “no.” The advantage of this system is that computers can memorize zillions of “yes” or “no” answers with incredible accuracy. The information can be stored and reproduced faultlessly at any time and there is no dependence on the accuracy of moving machinery. The disadvantage of this method is that curved lines are made up of little squares—and if you don’t make your squares small enough in the first place your reproduced image will not look like your original smooth wiggly line. I have demonstrated this by showing the difference between a good digital copy and one in which the small squares were too big.

The principle of digital reproduction. Both of these images were produced digitally—using a computer to divide up the curve into a collection of black squares. If we use millions of tiny squares (as we have done in the upper image) we see a smooth curve. If the squares are too large, as they are in the lower image, we lose a lot of picture quality and the shape of the curve is only recorded approximately. Modern hi-fi equipment uses “squares” which are so tiny that we cannot hear the effect of digitization.

Now that we know the difference between analog technology (which is used to produce vinyl records) and digital technology (CDs), we can answer our original question: “Are vinyl records better than CDs?” And the answer is… very very few people can tell the difference between the two (as long as the vinyl records are in perfect condition—and we use good equipment in both cases). This point was proved by a couple of music psychologists (Klaus-Ernst Behne and Johannes Barkowsky) in 1993. They took 160 people who were seriously into music systems and who had strong opinions about the CD/vinyl debate and made them listen to both types of music reproduction. Only four out of the 160 could actually identify whether or not they were listening to a CD—even though the vinyl fans all began the test thinking that CDs sounded “shrill and dead” compared to the “warm” sound of vinyl. Also, don’t forget that these weren’t just average listeners—they were keen, opinionated enthusiasts. The number of average listeners who could tell the difference between the sound of a CD and that of a vinyl record was probably less than one in a hundred—and that’s back in 1993. Improvements in technology since then have undoubtedly reduced this number and rendered the comparison irrelevant.

Much of the CD/vinyl debate can probably be attributed to technology nostalgia, which dates back to cave-dwellers having heated arguments about the superiority of bronze arrow heads compared with the newfangled iron ones. Back in the 1930s music fans were complaining that, because the new recording techniques could handle loud and quiet music, they missed the excitement of the distortion which took place in orchestral climaxes on their older records. Later, in 1963, a review of the latest technology (RCA Dynagroove recording) noted that some listeners found the new, smoother sound too sterile. Personally I think that the difference between vinyl and CD sound is bound to be irrelevant compared to variables like the ticking of the central heating, traffic noise, and the plaintive voice in the background asking if this jazz is going to be playing for much longer….

The difference between CDs and MP3 technology

Imagine we are at a concert watching our favorite band (the Psychedelic Death Weasels) playing their epic rock ballad, “Is my cocoa ready yet, luv?”

During the quiet, romantic verses we can clearly hear all the instruments, including the acoustic guitar which is being played by the singer. However, when the band plays the heavy rock chorus, all we can hear are the bass, drums and electric guitar. We can see that the singer is still playing his acoustic guitar but the sound he is making is completely drowned out by the other, louder instruments.

If this track was being recorded onto CD, every sound made by every instrument would be faithfully recorded as digital information—even the inaudible music produced by the acoustic guitar during the hard rock chorus. As far as the digital recording process is concerned, the same amount of data will be collected for the “hidden” guitar as for the much louder instruments. You wouldn’t hear these “hidden” sounds at the concert or on the CD, so the faithful collection of this data is pointless—but the recording equipment does it automatically because it doesn’t know how to pick and choose.

This “drowning out” or hiding of one instrument by another happens all the time during the performance of any type of music. Sometimes (as in the example above) one instrument is hidden for several seconds or even minutes. In many cases, however, instruments are only hidden for a fraction of a second—for example, a loud drum note might drown out a whole band or orchestra.

Apart from these hidden sounds, a CD also contains a lot of information that we simply cannot hear—frequencies which are too high or too low for the human ear. As we saw in earlier chapters, musical notes are made up of a family of related frequencies: the fundamental frequency, twice that frequency, three times that frequency, four times, five times, etc. If we play the highest notes on certain instruments, some of their harmonics will be out of our hearing range. Similarly, some combinations of low notes produce subsonic waves which are too low for human ears (although you can sometimes feel them). On a CD these inaudible parts of the notes are all stored and played back—even though we can’t hear them.

In the 1980s and ’90s a bunch of ridiculously intelligent scientists and engineers developed a method of using computers to identify all the hidden and inaudible information on music CDs. Once it was identified, it could be discarded and the music could be re-recorded without all that redundant information. Approximately 90 percent of the information on a CD can be discarded in this way to produce an MP3 file. This, of course, means that you could record ten CDs’ worth of music on one CD. Alternatively you can store and play back the music as digital information on a computer or personal stereo (iPods, etc.). Although MP3 technology discards most of the information that came out of the original musical performance, the average listener cannot tell the difference between a CD and an MP3 playback.

Home music systems

Music system enthusiasts, or “audiophiles,” can spend over a year’s salary on their systems—and if that’s what they want to do it’s fine by me. On the other hand, you can buy a music system which will approximately match the performance of your ears for about $1,000. I would advise you to go to a specialist music system shop which specifically advertises their goods as being high quality but cheap. I also recommend buying stuff second-hand from an enthusiast (enthusiasts tend to upgrade every couple of years and the equipment they buy and sell is always high quality). Up to about the $1,000 level, new equipment generally increases in quality as the price goes up—but it’s best to have a hi-fi enthusiast giving you advice or refer to hi-fi magazines for their “best under $1,000” choices. Between $1,000 and $3,000 the increases in sound quality can be difficult to spot and above $3,000 the money/sound-quality correlation disappears altogether, as far as I can tell. The different systems might sound different—but it’s very difficult to identify whether one is actually better than another. (It is possible to spend over $1,500 per yard for audio cables and I would be very interested to meet anyone who could tell the musical difference between such cables and ones which cost only a few dollars per yard.)

Having bought your equipment you now have two choices:

1. You can employ an acoustic technician and an architect. For $75,000 they will build you a special listening room and, when they have finished, they will make the biggest difference to the sound by trying the speakers in different places and moving the furniture about; or

2. You can save yourself $75,000 by taking the equipment home to a normal room, trying the speakers in different places and moving the furniture about.

The main difference between “pop” and “serious” music

Most melodies are only a few seconds long and what you do with this tiny bit of material is the source of the main difference between so-called pop and serious music. The following comments are not intended to make one genre sound better than the other—I love them both. Also, I am going to make some disgracefully broad generalizations in order to make my point.

A pop music composer will take two or three short musical ideas and make them into a three-minute song by playing them one after another. They will, for example, take tune “A” and make it into the chorus of a song, and tune “B” will be made into the verse. The song will then take the form: introduction—verse—chorus—verse—chorus—guitar solo—verse—chorus—finale.

This technique of continuously repeating the two tunes has several effects on the listener (assuming that the tunes are good ones):

1. It’s easy to remember the tunes.
2. It’s easy to get rapidly addicted to the tunes.
3. It’s easy to get bored with the whole thing after it’s been played thirty or forty times.

One common aspect of pop or rock songs is their use of a hook—a short, repeated musical phrase which is easily remembered. These can be melodic or rhythmic and usually last between seven and twelve seconds. Sometimes the song begins with the hook, as in the first five notes of “Whole Lotta Love” by Led Zeppelin or the first line of “Baby Love” by The Supremes. In other cases you have to wait a while before you hear the hook, which is what happens in “Momma Told Me Not to Come” by Three Dog Night, or “Teenage Dirtbag” by Wheatus. In all these cases the title words form part of the hook.

Composers of “serious” music are not averse to hooks either—just look at Beethoven’s Fifth Symphony, with its “Da Da Da Daah” opening. On the whole, though, “serious” music composers are a little more cautious and miserly with their material than pop composers. Their aim is to take two or three tunes and use them as the basis for a piece of music which might last between ten and a hundred minutes. This is done by using techniques such as breaking the tunes up and playing with the fragments; merging one tune into the other; playing one tune as the accompaniment to the other; and hinting that the tune is on its way. A composer of a long piece of music might use fragments of the main tune as landmarks to build up expectation—and expectation is much more important in long pieces than it is in short pop songs.

Many people, particularly classical music professionals, think that the listener retains some sort of appreciation of the key in which the piece begins and can sense the “homecoming” when we return to that key, as the music often does toward the end of a piece of classical music. I think this is a bit far-fetched. It’s expecting too much of the listener’s memory unless she has perfect pitch. Some studies have indicated that our memory of what’s going on harmonically only stretches back a minute or so, and this seems much more realistic. People will remember melodies or effects such as drum motifs from earlier in the music and will be pleased if they hear fragments of things they recognize. As far as the harmony goes, however, my analogy about different keys being like the rungs of a hamster wheel comes back into play. How are we supposed to know if the final rung is the rung we started on?

I think the experience of listening to a long piece of music can be likened to walking on a decorative carpet which is being rolled out in front of you and is being rolled back up a couple of yards behind you. As you walk forward new patterns and images appear and some of these will stick in your mind. Let’s say you saw an image of a tiger a few minutes ago and you can see the beginnings of a tiger tail coming up. The composer could choose to satisfy your expectation by showing you another view of the tiger. Or he could decide to surprise you—that “tiger tail” might actually be the rear end of a snake. If you listen to a piece several times and begin to know it better, you get fewer surprises and a better view of the whole carpet. You can also take a lot of pleasure from recognizing various landmarks as you go.

A skillful composer’s job is to create expectations and then either to satisfy or frustrate them. But the composer cannot and must not try for continuous excitement. As in any storytelling, or even a fireworks display, you deliberately add some calmer passages, so that the important moments make a greater impact.

These techniques for longer pieces result in music which is less easy to love at first hearing, but which seems to improve each time you hear it.

And finally…

Whether you like pop music, heavy metal or classical, you might find it interesting to listen to your favorite pieces and follow just one instrument at a time. Try playing your favorite pop song a few times while you listen only to what the bass guitar is doing; then do the same for the other instruments. You can learn a lot about how a piece is organized in this way and you will be really listening to the music rather than just hearing it.

I would like to finish with the best bit of advice that one listener can give to another. Whatever your present tastes, there are probably several other types of music out there which would bring you a lot of pleasure if you became more familiar with them. My advice is this: try adding a bit of randomness to your listening pattern, and give each new type of music a fair trial. If you are into heavy metal, try some folk music; if you love Mozart, try Dolly Parton. Musical genres are not exclusive, and one easy way to increase the amount of fun in your life is to expand the range of your listening.