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The 96kHz and 192kHz is better than 44.1 and 48kHz myth
I often hear that higher sample rates are required if we are to hear music properly. Despite the rather
obvious fact that our ears only go up to 18kHz at the very best for an adult and usually somewhere between 14 and 16Khz, (depnding
on age, health and the amount of exposure to loud noise) and the fact that no studio mics go beyond 22kHz, people claim to
be able to hear an improvement when listening to material recorded at higher sample rates.
At the same time, several scientific tests have shown that when the same material is played back at different
sample rates (and where the source material was at the very highest rate possible) none of those tested could hear any difference
between 192kHz and 96, 48, or 44.1kHz.
Many hi-fi companies and enthusiasts assert that the wider bandwidth and dynamic range of SACD and
DVD-A make them of audibly higher quality than the CD format. However many carefully controlled double-blind
tests with many experienced listeners showed no ability to hear any differences between formats. Therefore the
perceived quality has nothing to do with additional resolution or bandwidth.
And yet even I can hear a difference on some occasions! So what is going on?
In general, yes it does sound better, but not because we need the extra bandwidth or dynamic range to appreciate
the music, but because of the inadequacies of earlier equipment.
Earlier converters created all kinds of distortion
and even self-generated noises at the higher frequencies. One DAW even had a constant whistle at about 18kHz.
This lead to all kinds of unpleasant artifacts and distortion in the upper frequency ranges. The worst offenders
were DAT and ADAT machines, cheap computer sound cards and even some prestige converters.
This upper range distortion
was what some people called digital sharpness, or digital harshness. In reality, it was just good, old fashioned distortion.
When ever I mastered a piece of music that had been recorded, using an older box, the spectrum analyser would show the
line 'sticking' at the top somewhere above 17kHz. This is when I became interested in the subject and dug to find out
more.
Now, if you double the sample rate to 96kHz (or 88.2kHz for a CD) when making the original recording, then all
that distortion taking place between say, 14kHz and 22kHz is moved to between 28 and 44kHz - i.e. out of hearing range.
Suddenly,
all that upper distortion vanishes and we come to the conclusion that a 96kHz sample rate is superior to 44.1kHz.
Very
often, it is not even the converter's fault, but can be the result of poor cabling, or interference from other equipment. Discussions
with hardware engineers would suggest that clocking was a major problem for some systems.
So if you want to play it safe, record at the higher rate to ensure that no distortion
caused by jitter or other gremlins come in with the original material, but the improvement is not because you have golden
ears!
The cheap mics and monitors are every bit as good myth
I've looked at all sorts of speakers and mics and they all seem to have a very similar frequency
response. The same goes for mics. Lots of people say that the cheaper monitors and microphones are today every
bit as good as the top of the line stuff costing thousands. What's true here?
Let me be a little controversial -
We have been told by all sorts of manufacturers that linearity is the most import aspect of any transducer (i.e. mic
or speaker).
But then why is it that -
The NS10 is the most successful monitor in history, but it has a really poor frequency response.
The SM58 is the most successful mic in history, but it too has a poor frequency response.
The U87 is the most successful studio mic in history, but it (yes, you've guessed it!) has a poor frequency response
(OK, it ain't that bad, but linear it am not!!!)
And another thing - if frequency response is so important, why don't we use B&K test mics for everything? Heaven
knows, they're linear enough! The problem is, although they are perfectly linear, they do not sound that great.
What do we learn from this?
Easy - there must be something else going on!
Yes but what?
Go back, think about what happens - speakers and microphones are transducers, which is just a fancy word for something
that changes one type of energy into another. In this case, it's sound into electricity and electricity into sound.
Lets examine mic and speaker quality by being very silly and creating the World's worst speaker and mic. Both can
do both. You can stick a mic in your ear and use it as a speaker and you can connect a speaker up as a microphone.
But when you use one as the other, the results are truelly useless! By swopping them around, we have just built
the World's worst speaker and microphone!
Let's have a look at the reasons why they are so bad at their new jobs.
The speaker is big and bulky, it is designed to move air. It is not designed to be moved by air. A mic membrane
is small and light, it is designed to be moved by air. As a mover of air, it is rubbish.
The difference is compliance. The speaker complies with the electrical current and pushes air as accurately
as possible. The mic complies with the sound and tries to reproduce that as electrical current as accurately as possible.
The important difference is not the perfect (or otherwise) frequency response, but the accuracy of the result.
We can make the frequency response off the speaker used as a microphone as flat as any B&K test mic, but it will
always sound woolly and unnatural. We can do the same to the mic hooked up as a small speaker, but the result
will be a tinny and feeble sound, no matter what we try to do.
OK, using a mic as a speaker and a speaker as a mic may be somewhat extreme, but the same thing applies to microphones
and speakers within their own respective tasks. One will do a better job at some things than others. The difference
is the accuracy of the compliance. Or to put it another way, distortion.
All transducers of sound rely on mechanical movement and that movement is never perfect. Those imperfections are
called distortion.
Distortion simply means a deviation from the original signal.
Sometimes we like that distortion, as for example in the effect of an over-driven guitar amp. In studio monitors,
we should avoid distortion like the plague, because we need to be able to hear what is going on as accurately as possible.
Distortion in studio monitors is totally undesirable, because, even if we liked the sound of that distortion, there is
no way that we can insist that every person listening to our music will do so using the same speakers. We need accuracy
above all other things.
Unfortunately, most budget priced near-field monitors distort badly and do so, because they try to be linear, despite
being rather small and therefore not suitable for lower frequencies. They artificially boost their bass response by
having a tuned bass reflex port. This makes them sound 'sweet' to our ears, but also introduces unwanted resonances
(flapping about, I call it!) both at and around the boosted bass range.
Proper studio monitors get around this by having different drivers and amplifiers for each section of the frequency range.
Typically bass, mids and highs. They still distort, but considerably less than their semi-pro and amateur counterparts,
where the mid-driver is also having to act as a bass driver.
The ubiquitous NS10 (and many others like the M&Ks) get around this by being fully enclosed boxes - no bass reflex
opening and therefore no bass. Go find a sub if you want bass!
So what about frequency response and linearity?
Let me let you into a little secret (but don't go telling everybody!) It is not that important.
We have often been told that linearity of response in speakers was the most important thing to look for! In
reality, it is often a disguise for poor quality. Just as we can e.q. a mic used as a speaker so that its technical
specs would apear to make it a good speaker, we can do the same to a poor quality speaker. The technical tweaking makes
the frequency curve look nice, but it will still sound poor and not be very accurate.
Lets do a test. Have you seen any good concerts on television lately?
I did. I saw Tom Petty doing a live gig in Hamburg last week and I saw Beethoven's 9th being performed in the new
Dresden Fraunkirche. All good stuff and all with TV speakers and with an added sub of sorts. But definitely not
linear or even close!
But it did not matter, because my ears - well, actually my brain - got used to the non-linearities. Our brains
adjust to a non-linear sound very easily and quickly, but one thing we cannot compensate for is distortion. If the speaker
is 'damaging' the sound because the driver is flapping and puffing as it tries to reproduce sounds well outside of its
range, not only does that irritate, but the more we hear it, the more tiring and annoying they become.
The same applies to microphones.
The SM58 is designed to perform one task and one task only, close-up, loud vocals on stage without getting damaged.
You could not use it to record a concert grand piano or distant bird song. Because it only has to excel at one
thing, it can be built fairly cheaply. There are of course far better stage mics, but they cost a great deal more.
A studio condenser microphone is a different kettle of fish. It has to reproduce a wide range of sounds both near
and distant with great accuracy and also has to be built to within very fine tolerances, so that two combined will create
a perfect stereo image. This takes a great deal of time and requires very advanced equipment. And, yes, you've
guessed it! That costs money!
If we copy a high quality microphone, but we do not use the very thinnest membranes and we do not stretch them perfectly
over the frame and we do not use the very, very best components, we will still get a very similar sound, but it will contain
distortion and over a period of time, that distortion with rankle and irritate. Also, as each cheap microphone will
differ from its siblings, getting a good stereo image will be difficult or impossible as any two microphones will vary greatly
in their off-axis response and will distort in different places and in different ways.
The result would be that the musical instrument actually changes position according to which note is being played!
But that does not mean that you can assume that all expensive mics and monitors are good, in fact far from it!
Unfortunately, some manufacturers use (abuse?) the economic principle of the 'snob effect' (perceived quality, aligned
to price). They have realised that there is a market for relatively expensive equipment, that has a high profile.
These items do not sell well to the professional, but the amateur loves them. The amateur loves something new, the professional
has learnt (usually as a result of bitter experience) to distrust the new, until it has proven itself.
In other words, there's a great deal of rubbish out there, masquerading as quality.
So how can you tell what is quality and what is not?
The easy way is to ask a seasoned professional. Failing that, keep away from marques that have never ever manufactured
something like this before. If a maker of converters or software, suddenly launches a whole new range of microphones,
you can be fairly certain that he is just putting his badge on some budget mics.
Similarly, if a manufacturer of effects or wire or something, comes out with a new line of studio monitors, chances are,
they won't be of much use.
The running in of speakers myth
Many years ago, all car engines had to be run in for about 1,000 miles. At the end of this period,
the customer brought the car to the dealer and there the various bolts were tightened up and the oil was changed.
This arrangement was far from ideal, some people were more careful than others and some dealers did a better
job than others, so one engine manufacturer used a computer programme to run the engines against dummy hydraulic loads to
simulate 1,000 miles of perfect running in driving. Then the engines were put into the cars and no running in was required.
Customers complained and were mystified. How can a car already be run in? That does not make
any sense!
So this particular manufacturer did a test. They told a group of customers that they had
to run in the engines with religious care and they were even given totally over-the-top instructions on what to do.
There was of course absolutely no point to it, they were perfectly run-in already.
Another group was told to just drive. They were told the truth, there was no need to run them in,
a computer programme had already done a far better job than any customer could have achieved.
These two test groups were revisited over the next few years and there future choice of cars and overall
behaviour as customers was observed. The results were really surprising - not only did the run-in cars have slightly
fewer faults than the non-run-in cars, but the customers expressed greater satisfaction with them and were significantly more
likely to buy the same brand the next time.
The testers came to the conclusion that by actively involving the customer in the care of the car right
at the beginning, an emotional bond had been created. This in turn, meant that they took greater care of the vehicle,
drove more carefully and enjoyed the experience more.
Monitors are high quality (we hope!) hi-fi speakers. In the main, all monitor manufacturers are also
manufacturers of hi-fi speakers and put exactly the same drivers in both types. The only differences are marketing and
sometimes that the studio monitors also contain amps and crossovers to make them active.
With one or two minor exceptions, all driver cones are made of materials that, to all intents and purposes,
do not fatigue. For example KEF and B&W use glass-fibre and most paper cones are impregnated with various substances,
such as epoxy resins and UV resins that prevent warping and bending and also counteract the effects of fatigue that paper
alone would otherwise be subject to.
I have fatigue tested and repaired many, many speakers in my lifetime and the
only places where a speaker driver gets damaged is on the suspension and on the coil. Over time, the suspension can
wear down (paper) or rot and crack (rubber). A change in the sound only takes place when the suspension is badly damaged.
Even a cracked rubber surround is not audible until that crack goes all the way through the material, from front to rear,
in which case the speaker will start to buzz at certain frequencies.
Some manufacturers actually tell their customers that by running in their speakers, they are making them
more pliant. In the case of glass fibre and epoxy resin impregnated cones (and remember that is nearly all of them)
there is no bending and they are carefully constructed to avoid bending anywhere other than at the suspension. A driver
is suspended at the throat and at the outer edge of the cone. In a hi-fi or monitor driver, both are extremely soft and pliant,
so that the only effective resistance to movement is air. This is done to improve the response rate (the ability to
mirror the incoming signal accurately).
All hi-fi and monitor drivers for mid and bass have soft suspensions such as
a rubber surround or a cloth surround that allows the driver to move forward and back fully and completely, like a piston.
The main factors that decide the sound of a speaker is the mass and size of the cone and the compliance of the air mass to
the front and to the rear. All these are a given. You could drive that speaker for 100 years and the air, the
diameter and the weight of the cone will be the same. The same rules apply to the tweeter, which works as a fully enclosed
system.
There is one type and one type only of speaker that I have seen that changes its characteristics over time
and that is the stiff-suspension guitar cab driver.
In these, the suspension used to be made of the same materials
as the cone, i.e. paper and with time, the whole cone and suspension would become softer texture when the fibres
separated as the whole thing vibrated.
The changes are slight. We tested the changes that occurred over time
with a stroboscope, so that we could see the bending take place. A stiff-suspension causes the driver to bend the cone
into patterns at higher frequencies and in some cases, a worn cone would create slightly different patterns at given frequencies,
when compared with a newer sibling, but these changes are enough to give the final sound more harmonic distortion, not unlike
that of a valve (tube).
It is this creation of patterns that causes some of the sound that a certain guitar cabinet
to produce a type of distortion that the musician is looking for, so picking the right driver for the cab is important.
On the other hand, the main resistive load for a monitor driver in a closed box with soft suspension (rubber
or silicon) is the air it has to move and the air in the box in particular. Modern polymers as are used by all (as far as
I am aware) driver manufacturers are very elastic (ability to return to original form) and very 'un-plastic.'
This
is not true for paper cones that alter their mechanical characteristics significantly over time.
For that reason, guitar
amp drivers that have been on the road for a few years have more overtones than a brand new driver. Both the suspensions and
the cone itself are made of thick paper that loosens its structure with age and use and the resonant frequency of such a driver
can drop significantly. Paper cones loosen their structure and therefore reproduce certain frequencies and harmonic combinations
differently as they get older.
Paper cone guitar speakers rely on the stiffness of the suspension for a large part
of their resistive load. This can vary between 20% and 60%, depending on a whole host of factors, including volume, stiffness
and construction of the surrounding cabinet.
The stiffness of the suspension of a studio monitor is kept fairly low
and at the same time, the cones are made as stiff as possible, all by use of modern materials such as polymers and complex
glass fibre and polymer combinations.
Also, studio monitors are not supposed to be used to the full extent of the travel
of the cone. Put simply, they are (or at least should be) used at lower volumes, so as to avoid mechanical distortion.
These
are built into either fully enclosed or deeply ported cabinets and the resistive load of the air is therefore far greater
than for an open guitar cab.
Those two factors combined, mean that the mechanical resistance of the suspension accounts
for less than 20% of the total resistance. At low volumes, less than 10%.
Given that modern materials only marginally
alter their elasticity and plasticity and that tiny change effects a factor that makes up just 10% or less of the overall
compliance of the driver, we are talking about something that might alter a fraction of a percentage of the mechanical compliance
of the driver.
Headphone membranes are usually made of biaxially-oriented polyethylene terephthalate, which is a pre-stressed
(drawn) version of the same stuff that is used to make pop bottles (aka PET bottles). This stuff behaves in a very similar
fashion to modern studio monitor cones.
In short, run in the speakers on the your guitar stacks. The older and 'fluffier'
the paper, the more harmonics they will create - a bit like old valves really.
But the drivers in your high quality
studio monitors use air as their resistive load and last I heard, you can't run in air.
The leave it on overnight myth
Turn it off!
I have become aware of many studio owners who believe that it is better
to leave things all turned on overnight, in particular, large mixing desks (which use the largest amounts of electricity) .
So, for the purposes of this article, rather than just voice my opinion,
I went to the top and spoke to Graham Langley, former owner of Amek and of course a very famous console designer.
His advice - "Turn it off! There is no reason to leave equipment on
over night. Not only does it waste electricity, but it shortens the life of the desk. To put it bluntly, if you
leave it on all the time, it won’t last very long!"
Collin Adshead, manager of service company Audio Maintenance also
points out that there is no valid reason for leaving equipment on for long periods when it is not being used, but some very
good reasons for turning things off at night. "The one factor that has the largest effect on the life expectancy of
a capacitor is heat. By leaving things on when they are not being used, you are helping to dry out the capacitors and
that means having to perform a recap sooner."
Electricity Costs
If maintenance requires an expert, working out your electricity costs is
simple arithmetic. You need to know two things - the power consumption in kilowatts and the cost, which is
stated on your electricity bill and is usually somewhere around 7.5p or 15 Cents per kilowatt hour. Your electricity
meter will tell you how many kilowatt hours you are using in one hour.
In one case I looked at, the desk used 3kW, the machines used 2kW and the
air conditioning another 2kW. That meant that every hour they burnt off about 54p. The studio was used for 60
hours a week, so the machines were running for an extra 108 hours, when they should been switched off and that comes to £58.21,
or £2910 each and every 50-week year. Over a ten-year period that is ten times as much, or the cost of a really nice
brand new luxury car. Add interest and the cost of at least two recaps, and you can double that figure! Now you
begin to see just how wasteful leaving things running overnight really is.
Just leaving a rack full of converters and an Apple Mac on overnight can
add £4000 over ten years. Add all the other items in the studio, and you might just want to hit that circuit
breaker!
Software companies are being hurt by illegal copying
Some
of the small companies that have done nothing to protect their software are being hurt and hurt badly, but many of the Big
Boys actually like some 'illegal' copying.
I had better explain -
The trick to becoming a 500 lbs gorilla in the software market is market share. If all you are doing is
selling a niche product to a handful of specialists, then illegally copied or pirated (Kracked) software is deadly. Why pay
$10,000 for a video plug-in, when the competition down-loaded it for a Tenner? But for the usual suspects, niche products
are completely and utterly uninteresting.
In professional software packages that cost real money, you gain market share
by being good. In graphics, a good example would be SoftImage, in materials management, a good example would be SAP. The cost
for such software ranges from £20k to many millions and in some cases, even billions. It goes without saying that even a £20k
SoftImage package does not get pirated or illegally copied. This does not happen because large Unix systems are identifiable
(the software will not work unless the serial numbers match) and the software is sometimes verified via the Internet. Also,
much of this software (e.g. video editors) uses hardware processing, without which it would not work. A prime example of this
is of course ProTools.
The really big systems are not bought, but rented or leased over a fixed period. A great way
to gain market share for professional software is to offer very cheap (or even free!) versions to schools and colleges, so
that the next generation of office workers, sound engineers, video editors and layout artists will want your software when
they enter their careers.
For consumer software and cheap, mass market packages, there are other models for gaining
market share -
Shareware - it costs nothing, but a fully functioning system without annoying little reminders to pay
a small sum, will cost a few Dollars. This is how CoolEdit got going and this is how Reaper is gaining users.
Liteware
- a 'baby' version costs little, but has some limitations, but upgrading to the adult version costs a bit more. In audio,
ProTools, Soundscape and Logic (as well as others) use this well-proven tactic. Combined with hardware, this strategy has
shown itself to be safe and profitable.
Bundleware - Loads of stuff gets sold as a 'free' CD or DVD included with the
video editor, graphics card, CD writer or printer-scanner. If you buy a Matrox video system, you get Adobe's Premiere and
other toys included. The great bundling was, of course Windows, which came with almost every PC on Earth.
But the biggest
and most effective way software companies gain market share is also illegal!!!
Copyware - Call it what you will, pirating,
copying as a favour, 'sharing' with a mate, but it is the illegal duplication and distribution of software.
And it
is the software companies themselves who have gained the most by it and have done the most to encourage it.
It is how
MS-DOS got started. It is how MS-Office crept onto every office computer. It is how Corel Draw managed to become the most
popular design software in the early 90's, despite the fact that it was so buggy that one software expert described it as
a virus, masquerading as software.
If you find any of this difficult to believe? Do you still believe the line from the software industry, that they
are doing everything they can to combat piracy?
Try the following -
Get a copy of MS Office and install it. Use an older copy from the 90's and write rubbish
or nothing at all, instead of a serial number.
You get the message "You have entered an invalid serial number! Do
you still wish to proceed?"
You answer yes, and the whole package installs and functions perfectly for all eternity.
Adobe
made their 'illegal' users copy the serial number as well as the software (not much protection there!) or you could do what
Corel did for many years, and dispense with the serial number altogether.
This is The Valley's dirty little open secret.
It's a bit like the fact that everyone in the music business knew that Villi Vanilli did not really sing. We all know it,
but nobody can stand up and state that much in open court.
We can state this in forums and even on websites, but to
openly publish in, say The Wall Street Journal, an article naming products and methods would lead to massive litigation and
other retaliation.
Of course, no software company can afford to allow things to get out of hand, so minor irritants
such as time-outs on installing whereby the software does not install after a certain date. And of course the big two are
no tech. support and the fear of prosecution and prosecuting people for using more copies, then they have licenses for,
is dangerous and leads to much bad blood.
There is plenty of software that is properly protected. The trouble is, most of it is not very well known. Why? Simple
- you got to know most of the software on your desk as an illegal copy first.
Then you went out and bought the newer
and better, legal version - didn't you?
Every software company on Earth could protect their products tomorrow, if they
actually wanted to. They could do so via a dongle or via a software dongle. Or the serial number could be time-limited and
every couple of years, you get a new one, together with improvements and news of new products.
That's tomorrow. Today,
they could protect their stuff via on-line verification.
The day after tomorrow, they, as an industry, could insist that the BIOS carry an ID or that there is an ID chip
(EPROM) on the motherboard. Each serial number would be tied to that ID.
All these methods are already in widespread
use by those companies that want to protect their products.
Those that want you to 'spread the word' do not protect
their products.
For anybody to condemn 'illegal' copying as totally unacceptable at all times, is to misjudge
and misunderstand the market completely. But smaller companies are being hurt by illegal copying
- especially as it is the larger companies that benifit from it, by increasing their market share.
Bogus cables, bogus power conditioners, bogus interference suppressors and other bogus
products.
Line and mic cables
Let me state right now, that you will need good cables and a clean power supply. To use cheap
cables is a very false economy. If you then add cheap and tatty connectors at the ends of that cheap cable, then you
are asking for trouble!
BUT
There is no point in spending large sums of money on esoteric cable in the hope that it will somehow improve
your signal. Cable is always a completely passive element and there is no way that it can improve anything. Very
poor quality cable can degrade the signal, but ultra high-quality cable can do nothing for you.
The best analogue mixing desks can handle frequencies up to 100kHz, which is of course beyond the capabilities
of digital recording, but only just. (There is no point in going any higher, as you will end up in radio frequency range
and could end up listening to the BBC World Service or Deutsche Welle, rather than your latest and most brilliant recordings!)
A 192 kilo-bit converter has a theoretical upper limit of 96kHz, though you have to knock a bit off for filtering. Just
about any decent cable should be able to handle that kind of range. Input impedances and cable lengths play a greater
role than any magic properties the cable might possess. (Low impedance means you can run longer cables, before the top
end gets filtered off. Typically, mic cables can be 100m long, whereas line cables can suffer filtering after just 10m.)
Just to put that into perspective, the CD has a theoretical upper limit of 22kHz, hi-fi systems and amateur
recording desks usually filter off anything around 20kHz.
More importantly, just about every microphone out there caps its output at 20kHz or thereabouts - so exactly
where these sounds (that only bats can hear) are supposed to come from, remains a clouded mystery!
Speaker cables
The more power you put through from an amplifier to a speaker, the thicker the cable has to be. That
much is, I hope, common sense! Of course, most studio monitors are active (with the notable exception of the good old
NS10 of course) so there is no need for speaker cables.
But some speakers are passive and so you might find yourself buying speaker cable. If you buy some
two-core flexible mains cable then you are buying exactly the same stuff as speaker cable. This is the stuff (albeit
in a fancy package and using fancy PVC coatings that have no effect whatsoever on the conductive properties of the wire within)
that the speaker cables in that fancy package are really made out of.
But things get silly (and not a little dishonest) when that fancy speaker cable has directional arrows on
it. In fact I would go so far as to say that if you see directional arrows on any audio cable, you would be justified
in telling the vendor that they are either frauds, or just plain stupid. Either way, I personally would not buy anything
from that at all, no matter what it was.
It's like this - all analogue audio signals travel down cables in the form of alternating current.
That is to say, they alternate from 'plus' on one side and 'minus' on the other. Then the current reverses and
flows the other way. By putting arrows on their cable, they are clearly stating that the cable works better one way
about than the other. As the signal first flows in one direction and in the other, either they lack all understanding
of how electricity works, or they are trying to peddle falsehoods. You decide!
Dirty Power
There are companies that will try to persuade you that there is something wrong with the electrical supply
coming into your house or studio. In particular, they will try to tell you that there are all kinds of nasty radio frequency
interference (RFI) signals marching down the mains cable, bent on making everything that you record sound 'muddy' or whatever
hype word they go for.
The problem (for then) is you already have several devices that are perfect at getting rid of RFI.
They are called power supply units and everything has got one!
All equipment runs on direct current. The audio signal may be alternating current (AC) but all electronic
equipment uses direct current (DC) internally. The great exception is the Tonwheel assembly of the original Hammond
Organ that uses the AC frequency to drive an asynchronous motor invented by Larry Hammond and first used in AC-driven clocks.
But that is the only exception that you will find in a modern recording studio.
The incoming AC supply (roughly 230V in Europe and 120V in the US) is turned into the desired DC voltage
and current by a device called a power supply unit (PSU). Usually the incoming voltage is reduced by a transformer and
then a series of rectifiers and condensers smooth out the voltage to provide the exact value required. In a so-called
universal power supply, the reduction is performed by a series of thyristors, but the capacitors are still there.
These transformers and capacitors act as massive low-pass filters. Radio frequencies in the 100kHz
and above stand no chance! Also, all quality equipment had little filters known as 'taps' at the beginning and
end of all longer signal paths to prevent any RFI bleeding in from outside.
Various forums have seen a spate of UPS - power conditioner - balanced power - and other completely
unnecessary power 'cleaner' threads lately.
Let's get this straight, once and for all time -
1. An off-line UPS takes over when the power fails or drops below a certain value.
2. An on-line UPS replaces the in-coming power supply with a sine wave at the desired voltage at all
times.
3. Any UPS has to have a capacity of at least 50% more than the equipment to be supplied, if it is
not to create more problems than it solves.
4. Balanced power must, by law, be installed by an electrician and be protected by trips for both
sides of the balance in both the US and the UK. In the UK, ANY kind of fixed electrical installation must be performed
by an electrician.
5. Most power problems come from poor grounding. If you are in any kind of doubt, get a multimeter
and check that the resistance between neutral and ground is absolutely zero at all outlets. In Europe, the power supply
can vary greatly (too much leeway is permitted to the power companies here, IMO) between about 210 and 250 volts. If
it is outside those values, complain in writing, after checking with a second multimeter.
Check your grounding and supply, BEFORE you waste money on any kind of boxes! The magic box
that somehow solves gounding (aka earthing) problems has not been invented and never will be.
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