Hi, I'm Bartosz from Cyrus and in
this video i will tell you a bit about CD players and why we believe there
is still a good reason to invest in one. Do I need a CD player these days? We all realize that the
sales of CDs are going down and streaming is the leading force in the audio
industry today. But in our audiophile community CD players still occupy an important position as
they are still considered by many high-end purists to offer the best quality of audio available, far
better than what is achievable by many streamers. In this video i would like to explain
why CD players, at least the good ones, sound so good. And I'm going to start with
the basics of how digital audio works. Digital is always perfect. Or is it? It's a common belief that digital signal is
always perfect. And it's true as long as the signal stays digitized, as on a CD or in a computer
file. Then it can be copied and transferred without any loss in quality. This is why digital is so
popular with recording studios and as method of music distribution. However, human ears are analogue
and before we can listen to our favorite music this digital signal needs to be converted
to analogue waves that our ears can decode. And it's this conversion that has the biggest
impact on the perceived quality of audio. What are the best conditions for the conversion? The biggest challenge that an engineer
has to face when designing a product is to limit noise. You might think that noise
doesn't matter as the signal is digital and it can be recreated perfectly. Not quite.
Data travel through circuits as analog signal, a square wave for example, in which digital data
is encoded and as such these analogue signals are susceptible to noise just like any other
analogue signal. They can pick up noise from other sections inside the same product
such as power supplies, network modules, motor, error correction modules, etc. And any
possible noise added to the analogue signal in which digital data is encoded makes this
signal more difficult to decode without errors. And if errors occur some will be recovered
perfectly due to inherent error correction algorithms while others are interpolated or muted.
The noise of digital signal manifests itself as jitter meaning timing or quantitative errors
happening during digital to analogue conversion. As a result of jitter the reproduced analogue audio
signal differs from the one that was digitized. Noise is your number one enemy! Different sources have different challenges when
limiting noise. The advantage of CD players over streamers is the fact that CD players are fully
controllable. There is virtually no interference from the outside. This is much more difficult with
streamers where the ethernet and wi-fi modules add a lot of noise to circuits as computer networks
are very noisy beasts. Streamers usually contain some kind of a small computer which adds noise as
well. Additionally, clocks which play a vital role during the conversion can be fully optimized and
are generally much better in case of CD players as these need to work with only one bit depth
and sampling rate meaning 16 bit 44.1 kilohertz. One could argue that the advantage of streamers
lies in high resolution audio compatibility. True but without going into details better
sonic results can be achieved from a correctly reproduced 16/44.1 signal than from a high-res file
where the decoding environment is not as favorable. High-res may be seen as icing on a cake but what's
the point of icing if the cake is not edible? So coming back to CD playback - CD players are
still very popular among high-end enthusiasts as they offer unbelievable quality if designed
properly. In many cases they outperform streamers. Let us now look at what Cyrus has done. As I
said everything boils down to noise reduction as reduction in noise will allow
unbelievable level of detail to be revealed. Cyrus Servo Evolution Technology. Let's have a look at possible sources of
noise and what Cyrus has done to limit it. Noise coming from the motor (re-reads of the data). CD drives are these days manufactured with
computer and automative industries in mind. And there it is the speed and being shockproof
that matter. If errors occur the drive will re-read the data and if necessary correct the errors. In
high-end audio this is not acceptable. Re-reads add a lot of noise as they make the motor and laser
perform abrupt operations resulting in electric spikes. It is therefore much more important for
the drive to be slow, stable and error-free in order to eliminate those voltage spikes. This can
only be done by modifying the available hardware and writing tailored software controlling the unit.
It's very costly and not many manufacturers are able to invest in this. Cyrus has invested
a lot in its Servo Evolution technology that reduces read errors by about 20
percent compared to other top players. This is an important element that contributes
to the fantastic sound of Cyrus CD players. Noise coming from error correction circuits. Related to read errors is noise added by error
correction processors. in cases when a drive cannot read data properly the relevant
circuits will attempt to recover errors. Due to additional data encoded on a disk
to help with this there is a high chance many errors will be corrected perfectly. With
uncorrectable errors two approaches are taken: interpolation or muting. However, essentially
we do not want those circuits to work at all as when working hard they add EMF interference.
So fewer read errors that I talked about earlier will result in correction circuits being used less
frequently greatly lowering the level of noise. To demonstrate how Servo Evolution technology
helps limit noise we use an output from a spectrum analyzer showing a histogram of the radio
frequency signal generated after the laser reads the disk. These pictures are from exactly the
same disk playing exactly the same track. This is essential as things like how worn the stamper was
when the CD was made can also affect this picture. The left hand image is the Cyrus CD8X, one of our
legacy products using a mechanism produced by the best third-party supplier for cd mechs at that time.
The right-hand image is the Cyrus CD8X with our Servo Evolution technology. In an ideal world
you would get single spikes at each frequency but because of real world tolerances remembering
that a cd is a cheaply pressed bit of plastic with some silver paint on it the
right hand picture is close to ideal. As you can see the SE engine produces a
much tighter grouping around the peak making it much more apparent what data is supposed to be
read leading to the error correction circuitry having to do way less work. The image on the
left is showing many more errors. These errors are being caused by things such as motor speed
jitter and drift and the laser losing focus or tracking accuracy. With all this the CD still
plays okay as the error correction picks all this up and corrects it but error
correction circuitry is having to work much harder and therefore generating
much more electrical noise in the system. Noise coming from power supplies. Power supply circuits are extremely
important in every audio product and CD players are no exception. In case of CD
players there are a few things to consider here. First, noisy elements should be isolated
from the rest as much as possible. It is achieved especially with the addition
of the external power supply such as PSX-R2 that helps separate various circuits like
motor, motor controller, output buffers, etc . Secondly, in case of CD players with a DAC
board built-in it is crucial that the DAC receives a very stable reference voltage. Again
an external power supply improves things a lot. Thirdly, analogue output buffers which essentially
clean the analogue signal in which digital data is encoded benefit a lot from cleaner power supply. It is also one of the things that an external
power supply such as PSX-R2 helps with. Noise coming from D/A converter's filtering stage. In case of integrated cd players so those
with a built-in digital to analogue converter the applied filtering stage plays a vital
role. All DACs need to filter out frequencies above the maximum frequency that a given
sampling rate is capable of reproducing. At a sampling rate of 44.1 kilohertz the maximum
reproduced frequency is 22.05 kilohertz and it's very close to the edge of human hearing which
is generally assumed to be about 20 kilohertz. Therefore the filters need to be quite steep and
the steeper they are the more they will affect the audible frequency. In order to flatten the applied
filters and consequently reduce their influence on the audible range a lot of processing power is
needed to oversample the material. Cyrus current DACs can oversample the incoming signal even
up to 40 megahertz and as a result the content audible to the human ear is affected
very slightly by the filter itself. This is the technology that we use in our QXR
digital card. As they say the proof is in the pudding so do arrange a demonstration
with our local partner to find out how our CD players can improve your
listening experience. Thanks for watching!
