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Alex
Rosner:
»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 [the manufacturers] 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 db's [decibel] left above that
red marker where after which, it’s gonna be distorted, it's not gonna be
clear anymore.
So what you have to do is: You have to make sure, that the sound system,
which consists of what ever devices you've got connected to this, lets say
i.e. some processors, equalizers and amplifier and speakers. You wanna
make sure, that whatever the volts coming out of here, let’s say its two
volts or ten volts - it doesn’t matter, that that amount is more than
sufficient to drive the amplifiers and the loudspeakers to a playing level
that’s loud enough for the room.«
RBMA: »How do people or crowds come into the equation there?«
Alex Rosner: »Sound is measured in decibels, that’s the measure of
sound pressure. The sound has 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 there pretty loud. In the same time there is such a
thing as ‘too loud.’ But rarely have I ever heard a sound system 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 calculation, which shouldn’t be your function, but the function of
the sound system designer. And the way to design a sound system is very
basic and very simple:
First you pick the loudspeakers, how many loud speakers do I need to cover
this room? I know, I wanna generate, let’s say, 120 decibels of sound
pressure level.
To generate 120 decibels of sound pressure level, and you have
loudspeakers that are capable to do 100db, how many of these speakers do I
need in order to put out 120db? Well if this puts out a 100db – by the way
the academy’s loudspeakers put out a lot more than 100db, I’m just playing
with these numbers to make 'em even – then two speakers put out a 103db.
Four speakers put out 106db. Eight speakers put out 109db. Every time you
double the numbers of loudspeakers you go up 3db in power. So 120db would
take a lot of these loudspeakers.
So now I’ve got the number of loudspeakers I've 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 120db. So I need a 100 Watts power amplifier
for every loudspeaker. I could put two loudspeakers across each other
together - this is eight Ohms and another loudspeaker is eight Ohm and
[if] I put the two together it becomes 4 Ohms, because when you put two
loudspeakers together, it halves the impedance. An amplifier with 200
Watts per channel to four Ohms – terrific – it 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 gotta 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 at 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
speed at your own risk. It used to be years ago in England that the DJ’s
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 there things changed. In the United States the DJ definitely does
not pay for the damage and they do a lot of damage. They don’t mean to,
they really don't mean to.
I tell you a good story: There was a club, not so long ago, in which the
DJ that they kept not only damaged the sound system, 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 at hearing and the owner doesn't know it and I don’t
want to tell him, you gotta work with me, please help me. I need all the
help I can get.’ 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 a 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 sons
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 extremes because the
monitors that you listen to, usually play very loud and also earphones can
play very loud, that 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 overall young (looks around to the academy participants),
you have a long live ahead of you and you really need to be aware of this:
Don’t be heroes and not to play or not to be in places for any real long
period of time, where there is high sound pressure level!
What the sound pressure level is, it’s gonna 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 any meaning without a lot of explanation. It’s
fair to say that the office of something out of the United States, publish
a list saying what’s save and what’s not save. Their estimates are a
little too conservative. According to them, if you are in a room with 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 [determine]: ‘How much is loud?’ One of the problems is that, if you
are in a room where there is a sound system playing and as you are staying
there for a long period of time, after a while you don’t realize 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 realize it. Your
threshold shifts.
And there comes a time where you bring your watch up to your ear, you
couldn’t hear the ticking anymore. Because your threshold of hearing is
shifted and the ears are dead for a certain period of time, then 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 [if you want
to] find a way 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 dollars. 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 say that, if you like the sound or noise is being made,
that give 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. But, 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 the hearing is the only mechanism
that you can’t shut own. There are just no lids, so you have to protect
the ears and you have to be smart about it.
Whether you can use these ear protectors (imitates earplugs with his
digit fingers in his ears) 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:
‘Why, for heavens 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 gonna have a
better time and he’s gonna 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 - and if you don’t believe so, I’m gonna make it
louder!
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 or six years I’ve been only in New York clubs. Last
night it was the first time I went to a little club or a bar…
In New York, I can tell you that, women seat in this position (folds
his arms with a bored and skeptic face). Now, you don’t have to be a
shrink to know that this is a defensive posture. What are they defending
themselves? 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 them 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.
There was a Club called ‘Savage’ (uses the French pronunciation),
then 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.
And the landlord was about to kick him out, because he played too loud.
Upstairs 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 throw him out, losing liquor license and everything. So I got called
in: ‘What can I do?’ The loudspeakers where 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: ‘Ey, this is what I need to
turn the crowd on.’ I said: ‘Ok, I believe you. But, are you ready for
another job? You gonna have to get another job, because this owner is not
gonna go to jail, but he’s gonna loose his business. His investments gonna
be down the drain and you gonna be looking for a new job! So what are you
gonna do?’ He said: ‘What do you suggest?’ I said: ‘First we got to do
is 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
dance floor. They were spaced about 5 feet apart and the sound now came
directly to the dancefloor. The speakers were very close to the dancefloor
and at both corners, 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 we had
before on the dancefloor. I was going up into a tenants apartment with a
sound level meter and measured 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 to the dancefloor
measured the sound level [while] playing music and it was about 118db or
119db, which wasn’t very loud. I was worried about, that this owner was
losing his business anyway, because he is not getting any customers at
this low playing range. So, Saturday night came around and all the people
came in to dance and – surprise – all of them 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.«
RBMA: »There are rumors, that you are involved in stuff like the
‘cueing system’ and these kind of things«
Alex Rosner: »That is true. As I said, it happened to be that I was
at the right time at the right place. 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 uses
and public address systems use. And it seemed to me that one of those
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 technical
papers from Bell laboratories about [stereo]. That early ‘cocktail party’
effect.
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 do not 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 sends it to me for testing. He said:
‘Test it for ruggedness; I don’t 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 DJ’s probably don’t
drink coca cola’s, but I felt that coca cola was corrosive. Because I knew
when I put it on my car battery, it dissolves the corrosion at the battery
terminal. So I felt that had some effect. When I poured the coca cola in
the mixer fader it had no effect. So I got back to Bozak and I said: ‘You
got it, that’s it, it’s reliable!” Then the CMA 10-2 was born, that was a
standard of the industry.«
end
part 2 in PDF Format
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