Topic: Rotel CD Player

[Bogsle]

Mga bossing okay lang. Expounding further would be a futile effort to impress each other...

Lam ko naman nagkaintindihan tayo kahit medyo di absolutely correct or specific yung term na ginamit. Yun lang ang importante, diba?

[vvt-i]

Jetok,
. Two weeks ago napadaan din ako sa pier par bumili ng surplus na TV.
Nakita ko pics ng player mo . Piano finish pa!. Actually, wise move yan ginawa mo. You could
assemble or buy some inexpensive DACs in the future (khaolu or monica2 0

thanks for the suggestion.  jojod already made some mods with my surplus cdp.  i can now change the opamps and alter the sound of the cdp to my liking.  but if i have extra dough to burn, i will still get a rotel.  even a preowned will do.

[rascal101]

RESOLUTION : 8/12/18/24 Bit
- Actually it's like voltage & current they should always be together.

Why?

Resolution is actually depends on sampling rate when you say 96khz and 192 khz these are actually the resolution kaya nga sampling.

Resolution for converters is defined as minimum voltage that it can represent. eg 16bit

If the voltage reference being used is 2.5V, the minimum voltage is:

2.5/2^16= 38.1uV

In other words, if the analog signal is within the range it can represent it as a unique code. If the analog signal is between this range, it will be a gray area. Either it chooses the next higher or lower code is up to the subroutine.

8/12/18/24bit - is the speed how your processor reads the data. If i'm not mistaken 1bit is equivalent to 8 characters per second reading.

You are totally wrong. The converter is not the same as a processor. Pls remember that a coded digital stream si being converted to analog. Pls read about D/A or A/D converters.

By Analogy between AUDIO resolution (digital) by sampling rate in khz  and Picture resolution by Pixel, more pixel better resolution.

Resolution = number of bits, sampling rate = no of samples per second (based on Nyquist criterion)

[rascal101]

In computer parlance, 20 bit is really faster than 16 bit chips.
Since more digital datas are processed .
If 1 timba= 16liters of water at dadalin mo sa banyo ang isang timba
Mas mabilis kung yun timba mo eh 20 liters ang capacity.. Isang puntahan lang
20 liters na unlike yun isang timba dalawang puntahan. Mas mabagal

How a digital processor converts digital data to analog signal is
another topic that is technical.

When we say bits it means binary digits . Puro 0 at 1 yan. or on -me voltage off-walang voltage.
Mas maraming bits ,mas higher resolution ika nga so tama  yun analogy sa picture  resolution
more pixel better resolution. Ang problema lang sa upsampling, ang dindagdag na sample ay blanko.
Unlike picture resolution lahat ng pixel me laman na data. If smoothening the waveform is the objective,
we will never know. Since most audio reviewer knows that the software encoded on the chips is secret.

No, 16 bit is definitely faster than 20 bit for converters. The clock for the 20 bit converter is faster but the throughput is slower. Pls read about A/D or D/A converters. I believe the Linear Design Seminar from Analog Devices is downloadable. The analogy is just not the same.

I agree. 24 bit is the speed and 192 kHz is the sampling rate.
You can say "24bit/96kHZ CD player" or "0 sampling cd player".
So, theres nothin wrong when you say it's a 24 bit upsampling player. You just forgot the upsampling rate.Pag sinabi mo ang isang CD player is 24 bit (20 bit) kelangan mong sabihin kung 0 sampling iyan o 192khz sampling

This is a big no, 24 bit is not the speed. Pls do not compare the computer with a converter. 24 bit refers to the resolution of the converter. You can think of it like the pixel size.

The sampling rate refers to the number of points that is sampled or taken by the converter. This is based on the Nyquist sampling theorem which states that the minimum sampling frequency should be twice that of the signal frequency. For CDPs this typically is 44KHz which means that there is about 2 sample points taken in an audio signal waveform of 20KHz. Since the data on the disc is digital the converter then connects these points and goes through its waveshaping circuit block thus forming the waveform (analog).

Don't know where you are getting your information but your analogies are confusing. Pls make sure to read about D/A or A/D converters.

[rascal101]

I would suggest that you visit the website of:

Analog Devices, Texas Instruments, National Semiconductor, Wolfson Microelectronics

for a review on converters.

BTW, there is no software inside converters. For comparison it uses comparators.

[Voltraizer]

You ask any computer geeks. 20 bit dac can accomodate up to 1,048,576 input codes as against the 65,536 possible input codes for 16 bit dac.  And it's very simple computer process, more data and information processed
per required time, faster. Conversion of data(digital to analog) takes place in the processor. .

[rascal101]

The computer geeks DO NOT test converters Test/Product engineers do.

Suggest again that you read about A/D and D/A conversion process before you make comment.

[Voltraizer]

But it's the software programmer that encodes the d/A program on the the hardware (processor).

[rascal101]

NO! Tignan mo ngang mabuti iyung circuit block nung D/A or A/D converter kung may software siya. Hardcoded lahat through circuits. Better, magtanong ka ng designer o test/product engineer ng mga converters para malaman mo kung ano ang totoo.

[Voltraizer]

Assembly language program(low level language) can be encoded .

[rascal101]

Sir, you are entitled to what you believe and you can quote what is in the internet but that does not make it right. I have been a Test/Product Engineer for audio converters for over 5 years and not one of the converters being designed by my previous company was software driven. Nor do I know of the competition having a software driven converter.

[Voltraizer]

Ha, ha, ha Ian Harris said that in MF HIFI NEWS definitive Test.
 

[rascal101]

The internet does not necessarily provide you with the correct information. In in doubt, I suggest you read a college textbook on the A/D or D/A conversion process. The application notes from the semiconductor designers/manufacturers are also a reliable source of information.

[rascal101]

Yes this is a democratic country. Ingat ka lang sa mga tinatanungan mo o mga binabasa mo lalo na iyung mga audio reviews.

[av_phile1]

Interesting discussion.  I don't think you can call 24-bit or 16-bit as anywhere analogous to speed.   Ever heard of the term "wordlength'?  A 24-bit sample contains more data (0s and 1s) than a 16-bit sample.  One has a longer wordlength than the other.  It's a quantized sample of physical condition (in this case a waveform).  Each quantized sample can be represented by a wordlength of 8-bits, 16-bits 20-bits, etc.    

Now how many of those samples are taken every second, that's your sampling frequency.  The more the merrier, so you get closer to the sampled waveform, though Nyquist will argue you only need twice the waveform's frequency to be able to restore.  Together,  the wordlength and the sampling frequency define your resolution.  They go together.  

Oh, and yes, D/A and A/D converters are hardware based. True.   But they have instruction sets hardcoded into the chip.  An instruction set is a computer program.  Any computer program is a software.  A program, software or instruction set hardcoded into a chip is called a firmware.   And chips with erasable programmable capability can have their firmware upgraded from a download of a revised software.  Just my 2 cents.  Peace.  

[rascal101]

Interesting discussion.  I don't think you can call 24-bit or 16-bit as anywhere analogous to speed.   Ever heard of the term "wordlength'?  A 24-bit sample contains more data (0s and 1s) than a 16-bit sample.  One has a longer wordlength than the other.  It's a quantized sample of physical condition (in this case a waveform).  Each quantized sample can be represented by a wordlength of 8-bits, 16-bits 20-bits, etc.   

Now how many of those samples are taken every second, that's your sampling frequency.  The more the merrier, so you get closer to the sampled waveform, though Nyquist will argue you only need twice the waveform's frequency to be able to restore.  Together,  the wordlength and the sampling frequency define your resolution.  They go together.   

Oh, and yes, D/A and A/D converters are hardware based. True.   But they have instruction sets hardcoded into the chip.  An instruction set is a computer program.  Any computer program is a software.  A program, software or instruction set hardcoded into a chip is called a firmware.   And chips with erasable programmable capability can have their firmware upgraded from a download of a revised software.  Just my 2 cents.  Peace. 

Off the top of my head I would have to disagree. I will be going over my books tonight to end this ... BTW, just looking into the upsampling D/A converters ICs I couldn't see a pin being used for programming.

[rascal101]

Wow, av_phille.  That's not 2 cents worth reply. Thats $$$$$

Additional quote:
But in the case od digital-to-analogue conversion, it is Anthony Michaelson's feelin that technical performance is absolutely paramount.
.....\This folllows the high trend of offering oversampling to 192khz. This brings a software element into the equation, and at this level, programming is an art as a science."

I'm still not convinced. Pls take note that you are only quoting the upsampling process based on the internet. To be clear, I am talking of the whole A/D and D/A conversion process. Hindi lahat nag u upsampling although the trend is such.

I will try to dig up the notes I have on the person who developped the upsampling process.

[av_phile1]

RESOLUTION : 8/12/18/24 Bit

 8/12/18/24bit - is the speed how your processor reads the data. If i'm not mistaken 1bit is equivalent to 8 characters per second reading.

1 BYTE equals 8 bits.  And is not on a per second.  This is called your sample SIZE or wordlength.  Nothing to do with speed.  The speed with which your processor reads your data is more closely associated with Clock Speed expressed in megahertz or gigahertz.

[odyopayl]

The smallest unit of information a computer can use. A bit is represented as a "0" or a "1" (also "on" or "off"). A group of eight bits is called a byte.

Bits are often used to measure the speed of digital transmission systems


http://www.trainingfinder.org/CDC_lingo.htm

[rascal101]

A DSP is programmable, that much I understand. Yes the digital data has to be converted to analog but you do have a standard or proprietary waveshaping circuit that will take care of it. Now if you add a DSP after the D/A is another thing.

[bumblebee]

As I understand it, pag me processor, pede firmware. Kapag walang processor, "hard coded" na nga yung logic.

[av_phile1]

Bits are often used to measure the speed of digital transmission systems


http://www.trainingfinder.org/CDC_lingo.htm

Bits are the 0s or 1s.  In itself or themselves, they are not a measure of speed.  But it can be used like "bits per second" or "kilobits per second "or even bytes or kilobytes per second to measure bandwidth capacity in any digital transmission system, true .  But on its own, bits do not express speed.  It is a wordlength, analgous to a measure of size, of distance.  It becomes a measure of speed when you express it per unit of time.  Like distance.  Distance is not speed.  But when you express it over a unit of time, then it becomes a measure of speed.  So 16-bit or 24-bit is NOT about speed.  It is about size or wordlength in computer speak.  But when you talk about 24-bits per second, now that becomes speed. 

[rascal101]

As I understand it, pag me processor, pede firmware. Kapag walang processor, "hard coded" na nga yung logic.

Yun na nga baka naglagay ng isang DSP external to the D/A or kung custom internal sa D/A. However, I still stand that you do not need software or firmware in the D/A conversion process. Effects yung DSP.

[Voltraizer]

Yes, DSP is the manipulation of an audio signal in the digital domain kagaya ng
isang  loudspeaker is an example of product using DSP-based conversion
Alam ko sa loudpeaker ginagamit ito replacing capacitors, resistors and inductors
by using programs to be used as a high- pass and low-pass filter.

[Voltraizer]

Kasama ba itong pinag-uusapan natin sa ROTEL 1070. parang off-topic but interesting

[ronjet]

oh my...nahilo ata ako sa kakaintindi dito, but its all worth the read!...keep posting guys... healthy discussion ah!

[av_phile1]

Off the top of my head I would have to disagree. I will be going over my books tonight to end this ... BTW, just looking into the upsampling D/A converters ICs I couldn't see a pin being used for programming.

Not all chips with microcode are programmable or upgradable. 

[rascal101]

Agree

The theory on upsampling at best is theory. But companies have secrets. Di ka ba nagtataka, redbook CD is just 16 bit/44.1kHz lang. Why does companies uses the word 24 bit eh (20bits lang talaga yan)? Nagkakaroon ba ng new informations. Maniniwala ka ba pag nakalagay 24 bit cd player ,yun 16 bit cd mo madadagdagan ng information.
The original CD format was based on the assumption that human being living in earth can only hear up to 20kHz.(assumption)
Why oversampling tapos you cut the inaudible sound generated by oversampling. At most methodical inconsitency ito?
That's why software programming comes into the equation. And this is one top secret ng mga companya kung bakit ang mga cd players with24bit/192kHz DAC iba-iba ang tunog.

Iyung A/D or D/A conversion malinis na proceso iyun. Puwede maglagay ng DSP sa loob. Dun iyung tinutukoy mong programming. Ang tinutukoy ko eh iyung mismong A/D o D/A conversion process. Walang programming dun. I hope maliwanag na sa iyo.

[rascal101]

Not all chips with microcode are programmable or upgradable. 

Agreed the argument earlier referred to being upgradable.

Now that you mentioned it, not all DSP are programmable. The specific functions eg delay, echo etc follow a harcoded logic implemented via logic circuits.

[rascal101]

Yes, DSP is the manipulation of an audio signal in the digital domain kagaya ng
isang  loudspeaker is an example of product using DSP-based conversion
Alam ko sa loudpeaker ginagamit ito replacing capacitors, resistors and inductors
by using programs to be used as a high- pass and low-pass filter.

A loudspeaker is NOT an example of a DSP based conversion. And, DSP cannot replace your crossover network.

Programs can NOT replace filters. Programs affect logic, yes but definitely NOT filters. You are getting ahead of yourself. Masyado mong pinapalawak ang capability nung DSP. Paano ka makakagawa sa silicon ng malaking capacitor? Baka hindi pa umabot sa 1nF ang kaya ng silicon eh. Paano ngayon ang 20KHz cut-off ko? Lalo na sa CDP mahalaga iyun baka magkaleche leche ako sa aliasing.

Pls cite a specific IC naman so that I can follow you. Otherwise walang pupuntahan usapan natin.

To start off, eto mga IC ginagamit for sound effects

SN76477N and SN76488N

Daming gamit neto, percussion synthesizer, noise generator, tone generator pero wala filters gamit mga iyan.