Alex Rosner

ALEX ROSNER

I never was far from music. After my engineering education, I was fooling around and doing different things and the hi-fi bug bit me, badly. When the LP was invented in 1949 I was just entering high school. It was love at first sight and I could play records much better than I could play the piano. So I stayed with that.

The golden age of high fidelity began in 1949 and lasted through the ‘50s. Stereo became popular in about 1956 or thereabouts. A lot of people of that time didn’t think that stereo was an improvement. They kept saying that mono was really better, but it wasn't true.

Anyway, I got into this business very slowly, tentatively, but then jumped in with both feet eventually and by 1967 it was a full-time career. And it didn't disappoint. The good part is that it never was a decision between business or pleasure – the line of demarcation between private life and the business doesn’t exist, it’s just one life.

Most of you here are interested in reproduced sound as opposed to sound reinforcement, which is what this system is doing right now – it’s reinforcing my voice in real time. Most of you are more interested in sound reproduction, which means playing from some kind of a stored source, like a record or a compact disc or other sources. And there are basic principles. The way to think of it is: imagine five panes of glass, vertically, one pane of glass behind another pane of glass, and you are on one side looking through these five panes of glass onto an object on the other side. Each one of these panes of glass can represent a component in a soundsystem. The last component would be the loudspeakers. The component before would be the amplifier. The component before the amplifier would be the processing equipment – if any. The component before that would be the preamp. And then the playback device itself, whether it is a turntable, phono cartridge or tape deck, tape head or any electronics. You can also consider the acoustics of the space as a component. That would be even closer to you than the loudspeakers, because the sound has to travel from the loudspeakers to you.

The purpose of a sound reproduction system is to tell the truth: to reproduce it the way it really is. And the only way to make a fair test is to have an original, the actual source – you have to know what it sounds like, really. So a good way to test the soundsystem would be for me to play guitar, or some live instrument, and then record the instrument, play it back through the soundsystem and find some means to switch between the soundsystem and the real guitar. And that’s easier said than done. Because the moment you record the guitar in this room you add reverberation from the room, and even if you have a perfect soundsystem the guitar will never sound as good as it does if I’m just playing it. So it’s difficult to make that kind of test physically, but it can be done.

In fact, if we remember in the ‘50s, there was a speaker company called Acoustic Research, and they way they marketed their loudspeaker is they had a test – a chamber music group who would perform on stage, and they had two loudspeakers on both sides. At a certain point in the performance, they would switch – the musicians would keep moving their instruments but they weren’t really touching the strings, the loudspeakers took over. And the question was: could anyone tell when they switched between live and recorded? And the way they tricked the audience was that after the two notes they switched to the loudspeakers, so it was impossible to tell, since they only played a few notes in the beginning. And nobody could tell. Nobody admitted to being able to tell when the actual thing started. It was a promotional effort and it was very clever.

A good-looking loudspeaker helps. If you have a good-looking loudspeaker versus a lousy-looking loudspeaker, and they both sound identical, I promise you that you will choose the good-looking one. Which is also why these people that sell this wire that costs 60 dollars per foot, they sell the wire because it looks beautiful. It doesn’t do anything good – it’s not any better than ordinary wire. But they sell it because it’s so pretty. And since nobody can prove really that it’s not any better – it’s hard to prove – these people are selling it. There’s a company in Switzerland, who shall remain nameless, they make speaker wire that costs 60 dollars per foot. That’s the most expensive wire I’ve seen so far. So imagine you need about 30 feet from the amplifier to the loudspeaker – that’s a lot of money for wire. And if you used a lamp cord that cost 20 cents per foot, I promise you that you would not hear a difference.

TORSTEN SCHMIDT

With those Genelecs for example, there’s so much folklore to them – big rooms, the speakers are too big, and so on. Now that we've got the expert here, why not – I mean, you said it yourself – why shouldn’t we test this position here and find a good position for these speakers?

ALEX ROSNER

There are principles, and from experience, having done it a few times, I can pretty well guess what the best position is for this speakers in this space, but only from experience. There are computer programs that can make some predictions, but they are very time-consuming and you can easily make a mistake, so that's not as reliable. You mentioned that these speakers are too big, well, it’s like money: you can never have too much because you know you can give some of it away.

Loudspeakers never can be too big, because you always can turn the volume down. About 20 years ago I did a soundsystem for a chef. He said, “Can you put a pair of Klipsch horns in my kitchen?” Klipsch horns are very big loudspeakers, about five feet tall and four feet wide, they go into corners and are intended for a large room. So I said, “How big is your kitchen?” He said, “10 by 12 feet.” [Laughter]

I said, “Of course, no problem!” I put them in the kitchen and it sounded great. His issue was, would a pair of smaller loudspeakers sound better? And the answer was no. Why would a pair of small loudspeakers sound better?

These are wonderful speakers [in the lecture room]. The only question I had was whether they might sound better on the floor rather than on top of those cable reels. I think the reason they were raised is so the tweeter that’s on top could go over the heads of the people in front, so the people in the rear could hear. Otherwise if the speaker was a foot and a half lower, the people’s heads in the front would block the high frequencies – they go in a straight line – so the people in the rear might not be able to hear. I think that’s the reason they were raised.

TORSTEN SCHMIDT

So what is a frequency, how does it work?

ALEX ROSNER

Sound is composed of a wide range of frequencies. Low frequencies, the bass notes, and high frequencies, the high notes. Most humans can hear a range approximately between 20Hz, which is a very low frequency, sort of in the feel range, up to roughly 19KHz. As you get older you don't hear so good in the very high end. Most human speech falls in a range of around 100, 150 Hz to about 12, 13,000. Up there is just overtones, the bulk of the frequency range is in the mid-range for speech. Instruments have a much greater range and what separates the sound of the instruments are the very, very high frequencies. It would be nice if soundsystems could reproduce this entire range error-free, where each frequency was the same intensity throughout the range, but that's difficult to do. And an ideal loudspeaker would be one loudspeaker that reproduces the entire frequency range. There was a company in England that tried that, I don’t remember the name of the company. They had a five-inch loudspeaker that was made into a horn-loaded cabinet, so they were able to produce the bass and also the highs, but the highs didn’t go high enough, because to reproduce highs you really need a small unit. If it’s big it focuses the sound too much. To reproduce lows you have to move a lot of air, like a big piston, and it’s hard for one loudspeaker to do everything.

So what they do on a speaker like this [gesturing to Genelec speaker in the lecture room] is they break up the setup into three ranges: the bass, the mid-range and the highs. The crossover network determines which are the high frequencies, which are the middle, which are the lows, and it sends those frequencies to the different loudspeaker drivers. In this particular unit, they actually have three separate amplifiers: one for the woofer, one for the mid-range and one for the highs. So it’s three independent amplifiers and the crossover network is before the amplifiers. It’s a more elegant way of doing it. It's like putting the engine right on top of the wheels [of a car]. It’s easier to control, but audibly there isn’t much difference between this method and using one amplifier with the crossover after it. Crossover is merely a device that takes all the sound, it takes the high frequency and sends it one way, takes the middle frequency and sends it one way, and takes the bass and sends it a third way.

TORSTEN SCHMIDT

How do frequency, air and movement relate?

ALEX ROSNER

Oh, well, forget the soundsystems for a moment. The sound of my voice modulates the air, which means it pushes the air around. The molecules in the air travel through the air and reach your ears and you ear makes heads or tails out of it. That’s how the sound travels. Through a soundsystem, it's the loudspeaker that moves the air back and forth and modulates the air which then gets to the person’s ears.

Most of the energy in the sound is in the low frequencies. That’s why for low frequencies you need a lot more power than you do for high frequencies. Tweeters need very little power but loudspeakers need more power.

This is a direct driver loudspeaker. That means all the sound comes through the front. You can make a system whereby this thing feeds a horn and the horn amplifies acoustically the sound from the bass driver, so you get much more efficiency out of it. So a bass horn loudspeaker with a 15” driver would give you a lot more acoustic power than just a driver alone. The driver alone gives you cleaner power, assuming you have the amplified power to drive it. In a bass horn – a horn arrangement, you usually need a corner or some kind of a much larger enclosure – you get more efficiency so you don’t need so much power, or the same power goes a longer way.

TORSTEN SCHMIDT

So what would happen, if I can make it more understandable, if I compare a soundsystem in a club to, let’s say, a Jamaican sound system that I see on the streets of Notting Hill Carnival at a soundclash? What’s the difference between them? So that we get away from the specific terms but understand what is actually happening.

ALEX ROSNER

There’s no difference. It’s really the same thing, except in a club, in a room, the sound is affected by the acoustic space, whereas outdoors the sound goes out and isn’t reflected very much, it just keeps going. It’ s much easier to make an outdoor soundsystem than a sound system in a room. The soundsystem in a room is always affected by the room. The room is usually the enemy, not the friend.

This particular room happens to be a very good room acoustically because the ceiling is not parallel to the floor. That’ s enemy number one, when you have a ceiling that's parallel, especially when it's hard surfaces. The second is that the ceiling is slightly perforated so that it can absorb reflections to some degree. Third, we have a nice rug on the floor, that absorbs some frequencies. We do not have too much glass, the glass windows are not floor-to-ceiling, and the surfaces [of the wall and the interior] are very irregular. The more irregular you can make the surfaces, the better the acoustics are going to be.

An ideal room would be the golden rectangle. In Greek mythology you hear of the golden rectangle. The golden rectangle is a rectangle where each side of the room is times the square root of two of the other. The square root of two is about 1.416. So imagine a room that's, lets say, 10 feet by 14 feet by 21 feet. That would be a golden rectangle, or in those proportions.

Those proportions seem to be the best for sound, and where no two surfaces are parallel – so you have to have skewed walls. Whenever you see a recording studio, generally, that’s how they are made. Those are ideal rooms but normally we don't have the choice. When we are going to a space, then the room is given, so we have to work within the room, we can’t really fool around too much. All you can do is you can pad some of the walls or put cylinders in there, because the cylinder is a diffusing element that diffuses the sound. As opposed to a focusing element, which is a concave surface, that’s the worst.

When I do churches usually I have these domed ceilings and they are public enemy number one, because they focus the sound instead of spreading it around. So a bunch of columns or pillars, that’s wonderful. Any irregular surface, anything that doesn’t focus the sound back and forth, or makes it bounce around, is good. So this room is very good acoustically – you can get good sound reproduction in here, good sound reinforcement. You will have no trouble understanding me, it’s a good room. A good room for musical performances, too.

You can test a room. If you are going to a room and you want to know if it’s going to sound good, you just have to speak and have someone else walk around, and if he can understand you, it’s a good room. If he can’t understand you then it’s a reverberant room, in which case you have to do the following. Do not put speakers all around the room, because that gives you too many sound sources and each of the sound sources is reverberated in the room, so you will get a multiplication of the problem. Instead, focus the sound, centre the sound. Put the sound in the middle of the room. If it’s a very reverberant space, put the loudspeakers in the middle of the room in an omnidirectional way, so that the sound is aimed outward from the centre.

Imagine dropping a stone into water and you see the ripples going outward from the centre. That’s how this would be. That way you get the most intelligible sound. If you go to a big arena, like Madison Square Garden, you will notice they put the soundsystem loudspeaker cluster in the middle of the room and the sound goes outward from there and everybody can understand what’s going on.

As a practical matter it is hard to make a dancefloor, you know… if you put the loudspeaker cluster in the middle of the room, that wouldn’t be too popular. But I must tell you, I did it once – Casablanca Records threw a party in New York at the Hilton or one of those hotels, many years ago. And I looked at the room and it was impossible. I said, “You’ve got to be kidding, you can’t have a party here. This room is humongous and it’s going to sound atrocious!”

They said, “We don’t care, we’re having a party here. We got 4,000 people coming and you got to make it work!” It so happens that I was working on a soundsystem in another club at that time and I had all their equipment in my possession. So we took this system and made a circle out of it, a whole big tower of speakers, all emanating outward, starting in the centre of the room. And I took some white gauze and covered the loudspeakers with it. They called it ‘The Bride’.

And it became the talk of the town because nobody could understand how this system could sound terrific in a terrible room like that. That was never done since, they thought it was magic. I said, “It’s not magic, that’s just ordinary basic principles.” And they had to dance around ‘The Bride’, that’s the way it was. [Laughter] It was about three or four meters across in diameter, but the room was huge, so what? But the sound was not strong coming out since it was omnidirectional with eight loudspeakers. There were eight bass horns in the middle – it was a four-way system – eight lower mid-range speakers, eight upper mid-range speakers, and 16 tweeters on top. You know, a big tower.

If you were in front of one loudspeaker, you didn’t get killed because you only got some of the sound. All the other sound was emanating in all different directions. People didn’t really know where the sound was coming from. All they knew was that there were no echoes to speak of and the sound was really intelligible. The bass did not mask the rest of the sound, because what you would get if you spaced the bass speakers 30 or 40 feet apart, the bass is going to mask the mid-range and you get no intelligibility at all. This is one of the problems with clubs, aside from being too loud: the spacing of the bass loudspeakers being too far apart is a problem. One should try to keep the bass as close together as possible. A good place for bass loudspeakers would be under the stage, all together in one spot.

Bass travels omnidirectionally outward. You cannot control [it]. Even though this 15” loudspeaker in this thing [the Academy’s soundsystem] is facing that way, [towards the audience], believe me, as much energy is behind the loudspeaker as in front. The bass speaker sends the sound completely omnidirectionally, that’s the nature of low frequency energy.

High frequencies are different; you can have them around the room, because they are more or less focused. They travel in narrow beams, relatively speaking. Not like light, but in narrow beams that can get reflected.

If you put speakers into a corner, for the same power going to the speaker, you are going to get more sound coming out of it because the corner acts as an amplifier. You would notice when you’re speaking, if you back away into a corner you sound much louder than if you are away from the corner. If you don’t have a corner, put [the loudspeakers] against the wall. Here [in the Academy] we don’t have them against the wall because we don’t care, we got plenty of power. But if you want more loudness out of your speakers, put them against the wall and put them close to the floor or close to the ceiling.

The trouble with [putting a soundsystem] close to the ceiling is that you should keep the bass speakers close to the floor. The function of bass is to sort of vibrate our loins, as it were. That’s what you really want to do with bass. You don’t want to go down too low in the bass, because if you put out too much energy in a very low frequency range – it’s called the hypersonic region – you actually vibrate the sphincter muscles, which you don’t want to do! [Laughter]

The way these mixers are designed – all of them – is that there is a peak amount of voltage that this or any mixer is capable of putting out before distortion. The way they calibrate these things is that when the display device on the mixer begins to go into the red, that means that you have just a few more decibels left above that red marker, where after which it’s going to be distorted, it’s not going to be clear anymore.

So what you have to do is, you have to make sure that the soundsystem – which consists of whatever devices you’ve got connected to this, let’s say some processors, equalizers, an amplifier and speakers – you want to make sure that whatever the volts coming out of here – let’s say it’s two volts or ten volts, it doesn’t matter – that the amount is more than sufficient to drive the amplifiers and the loudspeakers to a playing level that’s loud enough for the room.

TORSTEN SCHMIDT

How do people or crowds come into the equation then?

ALEX ROSNER

Sound is measured in decibels, that’s the measure of sound pressure. You want the sound to be loud enough so that everybody could hear it. Actually, if the people are very loud in the room, then that loudness has to be pretty loud. At the same time there is such a thing as too loud. But rarely have I ever heard a soundsystem that is too loud. What I have heard mostly is distorted sound, which sounds louder than it really is.

So the idea is to create clean sound, and to do that you have to do some basic calculations, which shouldn’t be your function, it should be the function of the soundsystem designer. And the way to design a soundsystem is very basic and very simple.

First you pick the loudspeakers: how many loudspeakers do I need to cover this room? I know I want to generate, let’s say, 120 decibels of sound pressure level. To generate 120 decibels of sound pressure level, if you have loudspeakers that are capable of doing 100dB, how many of these speakers do I need in order to put out 120dB? Well, if this puts out 100dB – by the way, the Academy’s loudspeakers put out a lot more than 100dB, I’m just playing with these numbers to make them even – then two speakers put out a 103dB. Four speakers put out 106dB. Eight speakers put out 109dB. Every time you double the number of loudspeakers you go up 3dB in power. So 120dB would take a lot of these loudspeakers.

So I’ve got the number of loudspeakers calculated, now the question is how much power do I need? The manufacturer of this loudspeaker says that this loudspeaker wants to have a 100 watts for itself so it could put out 100dB. So I need a 100 watts of power for every loudspeaker. I could put two loudspeakers across each other together – this is eight ohms, and another loudspeaker is eight ohms, and when I put two together it becomes four ohms, because when you put two loudspeakers together, it halves the impedance. An amplifier with 200 watts per channel to four ohms drives two of these speakers per channel. So one amplifier [drives] four loudspeakers. So if I have 40 loudspeakers, I need 10 amplifiers.

Now I’ve got my system designed, basically from the amplifiers and the loudspeakers, and now my amplifier says, “Gee, if you give me 1.5 volts coming in, I can put out my full power.” So you have to make sure that this mixer puts out 1.5V. When you are into the red, you got to make sure you got 1.5V available. And if that is the case, you should never even go near the red. You should go way below the red, because if the red is a volt and a half, then that’s the maximum sound pressure level that you can ever use in the room. The way I calibrate the system is that I crank this thing [the mixer] up into the red and that’s my limit on here. And I adjust my amplifiers to give me the maximum power that I ever want to have in the room.

And I tell the DJ, “When you get into the red, you’re speeding. And you’re speeding at your own risk.” It used to be years ago in England that the DJs paid for the damage, but now [somebody] tells me that it’s not true anymore. They don’t do that in England, but they used to a long time ago. I guess things changed. In the United States the DJ definitely does not pay for the damage and they do a lot of damage. [Laughter] They don’t mean to, they really don’t mean to.

I’ll tell you a good story. There was a club, not so long ago, in which the DJ not only damaged the soundsystem, but more often he damaged the loudspeaker monitors in the control room. And I put some pretty beefy speakers in there, thinking that they will do the job, and he damaged them. I really couldn’t understand why. So he understood my problem and he took me aside and said, “Listen Alex, you just got to help me out here. I’m hard of hearing and the owner doesn’t know it and I don’t want to tell him. You got to work with me. Please help me, I need all the help I can get.” It happens. He was a wonderful young man, had a big following and was a great DJ. [But] he was hard of hearing. I had to put in real studio monitor speakers, not unlike these [at the Academy], which is really overkill, but he needed them to hear. And he never blew another piece of equipment after that on the dancefloor, once he had his monitors that he could hear.

If you stay in clubs long enough, where they are playing a sound pressure level of 100dB to 125dB, your hearing will be impaired irreversibly. And chances are that my hearing is not as good as my son’s hearing. I mean, I can manage, I can still hear everybody pretty well and I can have a conversation, but if my hearing was measured, probably there is some damage because of my vocation. DJs are also in extremis because the monitors that you listen to usually play very loud, and also earphones can play very loud, so over a period of time they do some damage. So you really have to take defensive action if you want to protect your hearing. You’re all very young, you have a long life ahead of you and you really need to be aware of this. Don’t be heroes, [don’t] play or be in places for any real long period of time where there is high sound pressure level.

As to what the sound pressure level is, it’s going to take a little study on your part to know. It’s a complicated subject and I can’t just give you direct numbers. That wouldn’t make anything meaningful without a lot of explanation. It’s fair to say that OSHA – which is the office of something out of the United States – publish a list saying what’s safe and what’s not safe. But their estimates are a little too conservative. According to them, if you are in a room that’s 95dB for three hours, you are going to get hearing damage. Well, 95dB is a loud conversation in a room. So that isn’t really practical, but you have to do some determination for yourself as to how much is loud.

One of the problems is that if you are in a room where there is a soundsystem playing, as you are staying there for a long period of time, after a while you won’t realise how loud it really is. A person walking in from the street would get hit right away very hard and know that it is loud, and you wouldn’t realise it. Your threshold shifts. And there comes a time where you bring your watch up to your ear, you can’t hear the ticking anymore. Because your threshold of hearing is shifted and the ears are dead for a certain period of time. They will recover again, assuming that you did not sustain permanent damage.

I think you need to get a little education in that area and find ways to look it up. You will find it. It might not be a bad idea to have a sound level meter. Radioshack sells a cheap sound level meter for under $50. A sound level meter can tell you in decibels how loud the sound is where you’re hanging out. Those who are exposed to sound over a long period of time are the ones that I’m really concerned about. The ones that go in for a few minutes or for half an hour or so, that is no problem. It’s just the sustained presence in a sound environment that’s very loud is very detrimental. I read someplace some study where they said that if you like the sound or noise that’s being made, that gives the ears some kind of protection. Because if you don’t like it, there is something like a ‘wince muscle’. And the ‘wince’ makes the problem worse. I don’t know if that is true or not. To be honest with you, I have my doubts, but I did read that some place. The idea behind the article was if you love the music, it’s OK. Well, I don’t think so. I think the ears really have no way of telling if you like it or not. The heart may long for it, the ears are connected with the heart, but they also have little follicles in the inner ear, which get burned whether the heart likes it or not. So I think you need to take some defensive measures, and hearing is the only mechanism that you can’t shut down. There are no lids, so you have to protect the ears and you have to be smart about it.

Whether you can use these ear protectors or not is a personal thing. I myself find it very awkward. Because when you stick those ear protectors in, they don’t protect across the board at all frequencies, so the sound that you do hear doesn’t sound natural. So it’s not a satisfying experience. It’s better than nothing, I suppose, and it will protect you to some degree, but I don’t think that this is the solution. I think the solution is not to be in a place where you’re really not wanted.

Which then brings us to the corollary to this argument, which is why, for heaven’s sake, would anyone want to stand in a place that has damaging sound pressure levels being used? That is the question that I would like to address for a few minutes. It’s a good question.

You know, when you hear bands play, [there are] two things that I notice immediately. The poorer the band, the more they speed up as they play. They don’t keep a steady beat. They start slowly and they speed up. Inadvertently, I don’t think it’s deliberate. Number two is, they get louder when they play.

The explanation for the first is that they are not aware of speeding up. It’s natural, they get excited and they don’t have the presence of mind and discipline to hang back a little bit on the beat. The drummer is really the one supposed to guide them, but he gets carried away too. So the beats per minute at the end of the song are guaranteed higher than the beats per minute when they start. Whereas a professional band doesn’t have that problem.

Also, getting louder. They get louder because they think that they are going to energize the audience more with their loudness. The DJ thinks the same way. He doesn’t speed up, because he’s got a machine that keeps a steady beat. And he is playing a record that was made in a studio that’s probably on speed. But he thinks that by raising the volume he’s going to energize the audience and the audience are going to have a better time and he’s going to be more appreciated. This point of view, unfortunately, is about me [points to his chest]. It’s not about the music and it’s not about the audience. It’s about me. I am doing my thing. I want to look good, I want to be popular and I want you to love me. I am a great DJ. [Laughter] And if you don’t believe so, I’m going to make it louder. [Laughter] This is a disease.

If you go to a club these days, it’s worse than ever, at least in New York. In the last five years I’ve only been in New York clubs. In New York, I can tell you that women are seated in this position [folds his arms with a bored face]. Now, you don’t have to be a shrink to know that that’s a defensive posture. What are they defending themselves against? You think that they defending themselves against the jerk that they are with? I don’t think so, they don’t need defense for that. They are defending themselves against the sound. There is a sound onslaught. And women express themselves better than men. Men usually have their hands in the pockets or they just slouch. Women really express themselves and you can see if I am wrong – if you walk into a club next time, look at the position of the women that are seated.

I once did a club called Sauvage – they changed the name to Club Elite – in New York on 23rd Street. It was a black club, and it was very hot. The guy was doing great business but the landlord was about to kick him out because he played too loud. There was a hotel and there were people complaining, and the Environmental Protection Agency gave him summonses, and the fine would rise every time they came. And it got to the point where the next step was that they were gonna throw him out, he’d lose his liquor license and everything.

So I got called in. “What can I do?” The loudspeakers were hung on the walls and the DJ was playing at outrageous loudness. He was a good DJ, too, but he was absolutely outrageous and his position was, “Eh, this is what I need to turn the crowd on.” I said, “OK, I believe you. But are you ready for another job? You’re going to have to get another job because this owner is going to lose his business. His investment’s going to be down the drain and you are gonna be looking for a new job. So what are you going to do?” He said, “I don’t know, what do you suggest?” I said, “First we got to take the speakers off the wall, because they are vibrating the walls.”

It was a long, narrow room, so I put 16 JBL speakers on each side of the dancefloor. They were spaced about five feet apart, where the sound came directly onto the dancefloor. The speakers were very close to the dancefloor and at both corners, the length of the dancefloor, I put two big bass horns, one on each side. That was it! The sound pressure that we were reading was 10dB lower than what he had before on the dancefloor. I set the volume by going up into a tenant’s apartment with a sound level meter and measuring the sound level that I could just about hear up there. That to me was the speed limit. Because any above that they would complain about, and up to that they wouldn’t complain. So knowing what that was, I came back on the dancefloor, measured the sound level [while] playing music, and it was about 118dB or 119dB, which wasn’t very loud. So I was scratching my head and I was worried that maybe this owner was going to lose his business anyway because he’s not getting any customers at this low playing range. So, Saturday night came around and all the people came in to dance and – surprise – they all had a great time. Nobody complained! They said, “Gee, it sounds so nice and crisp and clear, we get lots of bass on the floor, it sounds terrific.” And everybody was happy.

TORSTEN SCHMIDT

There are rumors that you were involved in stuff like the cueing system and these kind of things in the mixer.

ALEX ROSNER

That is true. As I said, it happened to be that I was at the right place at the right time. There was a time when all the mixers were mono. In the early days the mixer was a broadcast mixer only used in broadcast. That’s all it was, the radio stations weren’t in stereo, it was all in mono.

There was a guy named Louis Bozak who made mono mixers for broadcast use and public address systems use. And it seemed to me that one of these mixers that he had – which had ten in and two out, to go to two zones – was a perfect vehicle which with some modification you could make a stereo mixer. So I said to him one day, “What’s really needed out here is a stereo mixer, because stereo is the way to go.” I had read the papers from Bell Laboratories about [stereo]. They had published technical papers about that early ‘cocktail party’ effect. So I knew that stereo would be a good thing to have in clubs. And up until then, I made my own little stereo mixer using two headphone amplifiers for the cueing system and a sliding fader – a very, very primitive device. My technician painted it red so they called it Rosie, because it was rose red. And when I met Bozak I said, “I don’t really want to manufacture these things, but I think you, as a manufacturer of equipment, can make a stereo mixer.” And he said: “OK!”

He made the original mixer and he sent it to me for testing. He said, “Test it for ruggedness.” I didn’t really know what to do, so I took a bottle of Coca-Cola and I poured it on the mixer. That was my reliability test. I thought that was a realistic test, little knowing that DJs probably don’t drink Coca-Colas. But I felt that Coca-Cola was corrosive, because I knew when I put it on my car battery it dissolved the corrosion at the battery terminal. So I felt that had some effect. When I poured the Coca-Cola into the mixer fader it had no effect. So I went back to Bozak and I said, “You got it, that’s it, it’s reliable!”