Question regarding streaming WAV files

ajinkya

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I'll begin my question with a bit of background. I've recently convinced my iPod-carrying friend to go the hifi route (the trials and tribulations of this endevaour are a separate story). He has finally bought a Denon AVR and has his entire CD collection on harddisk in lossless WAV format (useful for his ipod music). He wants to stream his collection from his PC to a media server, since he already has everything in digital format. So he is adamant about not buying a good CD/DVD player until he is convinced of reasons why. And his why is where I started pondering. Since we both are engineers, to convince him I need to convince myself and hence the reason for this post. And so here's the long-drawn out question-

Is streaming lossless WAV to a media server, which is connected to an AVR via COAXIAL cable (very imp.) any worse than playing the same media through a dedicated CD\DVD player?
-Let's assume that the WAV files were converted from CD using good hardware and software. By this I mean he has a high-end Soundblaster kit with software and dedicated PC that has no other process running while he is converting CDs/DVDs. So far, I assume that the transfer from bits on CD to bits on HDD is pristine (correct me if this assumption is itself flawed).
-Now we stream this over a strong wireless network with negligible packet loss (he has a pre-N router so enough bandwidth for hi-res audio).
-It reaches the media server via the network (he is using a DLink DSM-520 but any one will do). The server is connected via coaxial to the digital coaxial input of the Denon.
-So far in this chain, I am only seeing bits being transferred. There is no digital-to-analogue (DAC) involved (again, please chime in if you see any flaws). The bits are being send to the AVR where the D-A conversion takes place for the first time and then the signals are processed and sent out to the various 2.1/5.1 speakers and we get sound.

If the above chain is valid, then the only hi-fidelity analog component needed is the AVR's DAC, since there are bits everywhere else which is just data. In such a scenario, why will a dedicated CD player connected to the AVR sound any better than the media server? I am assuming that the AVR and CD player have comparable DACs for sound conversion.

Sorry for the long post...just wanted to get your thoughts since this has been vexing me since morning. Looking forward to your solutions/answers.
 
In short, there shouldn't be any problem. However, there are couple of things that needs to be checked. First error free conversions are possible only if he had used extra software (I don't think this requires any extra hardware). So, assuming that this step was done fine, the next thing is that in digital sources, the most important words I hear about are - jitter and clock synchronization. So, though the media server is sending the data through coaxial, if he uses a DAC that does reclocking and reduces the jitter, then that will improve the preformance noticibaly. Given that his data is coming from a media server, the server might sometimes be busy in other things as well and not just doing this unlike a traditional CD player. So, someimes there might be audio dropouts unlike traditional players. I think overall, both the mthods should be pretty damn close. Also, understand that you are comparing the DAC of the CD player to that of your AV receiver. In that sense, the correct way to compare is to use the CD player vs an external dac with wav files. Infact, if you have decided to use the AV Receiver's DAC, you can as well use the DVD player for playing CD's. So, to achieve good stereo you need an external DAC.
 
ajinkya said:
Is streaming lossless WAV to a media server, which is connected to an AVR via COAXIAL cable (very imp.) any worse than playing the same media through a dedicated CD\DVD player?

There have been an heated discussions going on on this topic for the last few years. Technically, if you convert a CD into lossless format, you have a identical copy in your hard disk. Magazines and reviewers have done innumerable tests for the last few years, and this is an accepted fact that the files are the same. So whether you play from a CD or from a hard disk, you will, in it's digital form, get the same output.

The reluctance to move from CD to a lossless format is more subjective and has to do with the DAC conversion and whether using a wired or wireless system, you will get 'all' the data on the other side. Using a wired system, of course, any computer guy can tell you that using a CRC error or similar checks, you will not lose any data as it moves across the network.

But a wireless? Enter the Squeezebox and Sonos. These two systems, one costing just 200$ and the other costing about 1500$ changed the face of the wireless music industry and brought across even staunch disbelievers. More and more people around the world have moved to HDD based system, and are actively converting their CDs into lossless formats. The Squeezebox has a elder brother called the Transporter, that is supposed to be real Audiophile grade.

Stereophile has a number of articles, but here is what John Atkinson says in brief, and I quote

Lossless compression is benign in its effect on the music. It is akin to LHA or WinZip computer data crunchers in packing the data more efficiently on the disk, but the data you read out are the same as went in. The primary difference between lossless compression for computer data and for audio (as on a Redbook CD) is that the latter permits random access within the file. We recommend that, for serious listening, our readers use uncompressed audio file formats, such as WAV or AIF, or, if file size is an issue because of limited hard-drive space, use a lossless format such as FLAC or ALC. These will be audibly transparent to all listeners at all times with all kinds of music through all systems Unquote.

ajinkya said:
-Let's assume that the WAV files were converted from CD using good hardware and software. By this I mean he has a high-end Soundblaster kit with software and dedicated PC that has no other process running while he is converting CDs/DVDs. So far, I assume that the transfer from bits on CD to bits on HDD is pristine (correct me if this assumption is itself flawed).

John is tricky in his statement. he uses the word 'benign' so that he can back out when needed. Later on he goes on to say that a FLAC, AIF, or a WAV file is identical to a Redbook CD file. If you take a lossless compressed format or an uncompressed format, reconvert it to the Redbook CD form, and compare the two, it will be identical bit for bit. So how can the music be different?

I have over 300GB of data already, and I am continuously converting all my CDs into lossless formats. By next year end, I will be using only HDD based systems for all my music listening.

If you use good hardware and software, the CD and HDD version will be identical. I am not sure if your aware, but the best software for conversion is Exact Audio Copy (Introduction � Exact Audio Copy). The sound card that Andre Wiethoff, the writer of EAC uses is available in India (Marian: Trace ALPHA), and I plan to buy that.

ajinkya said:
-Now we stream this over a strong wireless network with negligible packet loss (he has a pre-N router so enough bandwidth for hi-res audio).
-It reaches the media server via the network (he is using a DLink DSM-520 but any one will do). The server is connected via coaxial to the digital coaxial input of the Denon.
-So far in this chain, I am only seeing bits being transferred. There is no digital-to-analogue (DAC) involved (again, please chime in if you see any flaws). The bits are being send to the AVR where the D-A conversion takes place for the first time and then the signals are processed and sent out to the various 2.1/5.1 speakers and we get sound.

If the above chain is valid, then the only hi-fidelity analog component needed is the AVR's DAC, since there are bits everywhere else which is just data. In such a scenario, why will a dedicated CD player connected to the AVR sound any better than the media server? I am assuming that the AVR and CD player have comparable DACs for sound conversion.

The CD and the HDD based file should sound the same. The reason why products such as Squeezebox and Sonos have a high end DAC is because they are competing with the CD players and are trying to send jitter free data across. It is generally believed it is better to execute the DAC conversion as close to the source as possible as you can re-sample the data when there are errors. The AVR or similar device is used for just amplification. It is also common fact that high end CD players provide better DAC circuitry.

As external DACs (such as DAC1) are getting better, it really does not matter where the conversion is done. You can do it at the source, the amp can do it, or you can have an external DAC doing it. In terms of data movement theory, it does not matter. But which is better? That depends upon the unit at each part of the chain. But yes, given the same equipment across the chain, and you have a well converted digital file, it should sound the same as the Redbook CD output.

Cheers
 
There have been an heated discussions going on on this topic for the last few years. Technically, if you convert a CD into lossless format, you have a identical copy in your hard disk. Magazines and reviewers have done innumerable tests for the last few years, and this is an accepted fact that the files are the same. So whether you play from a CD or from a hard disk, you will, in it's digital form, get the same output.

There is a catch here. If you look at the Redbook CD format, you'd notice that the way it uses Reed Solomon Encoding, there's no real deterministic way to find what a particular bit on a CD is when error correction is invoked. The only thing you can potentially do is read it again and again until you are certain that its the same bit. However there's a catch here again. The CD transport might have its own error correction mechanism which gets invoked when reading the disc and in theory it is possible that a particular dirty bit is read wrong every single time due to faulty error correction.

In practice, this is so rare that such a phenomenon will potentially *never* happen. With EAC you can compare the checksum of a particular ripped track with its online database and hence there's a second level of added error checking.
 
Thanks to all for the quick and detailed responses. So there really is only 1 DAC in this chain and the final audio performance will (of course) depend on its quality. Fair enough and I agree with Venkat's claim that dedicated CD players have better circuitry (potentially).

Venkat:
Thanks for the additional info on media servers and EAC. I have seen both Sonos and Squeezebox. And I do not believe it's worth the extra money over something like the Dlink DSM. Because, both the above products stream only audio files. DSM streams both audio and video, which makes it a better budget buy. The other media streamer is PopcornHour, which is gaining popularity because of its support for various HD formats. I think any one of us with a dedicated PC and wireless router can make a much cheaper and equally good mesh network, like the kind Sonos publicises. The ZoneP and controller are grossly overpriced for what they do, which is transfer bits across distances wirelessly and reconvert with reasonably fidelity. However, if music is the only data one is transferring, the Squeezebox may be worth re-investigating for me.
I also find it funny when these reviewers actually debate lossless compression schemes for music, when all their bank data, sensitive tax data and virtually all online data is using some sort of lossless compression to store on servers. Aren't they worried about "rounding errors" and "loss of accuracy" in their bank accounts? ;-) Sometimes audio fidelity arguments from these guys border on obsession and stubborness to accept new technology.
Have you tried the Squeezebox personally? If so, did you find the quality commensurate with the cost?

Gopi,
Thanks for the answer. I should have made it clearer that the 'media server' he is using is actually a media streamer. In other words, it is dedicated to that one task while streaming. Your point about audio dropouts if server is overtaxed is absolutely accurate.

RoC,
Thanks for the tip with EAC. But do you think that with today's CD transports, and speed of conversion that errors being missed is still a possibility? You're right about the CD hardware having its own wired error correction. In fact, the entire CD read system is a highly sophisticated control system that uses all kinds of tricks to make sure data is read evenly and accurately on each pass.

I think the best thing I can do is tell him I lose, let him have his WAV files :) and maybe put a DAC (Beresford good for budget?) between the media streamer and the AVR. If anyone has a better scheme, I'm obliged.

Thanks,
Jinx.
 
I also find it funny when these reviewers actually debate lossless compression schemes for music, when all their bank data, sensitive tax data and virtually all online data is using some sort of lossless compression to store on servers. Aren't they worried about "rounding errors" and "loss of accuracy" in their bank accounts? ;-) Sometimes audio fidelity arguments from these guys border on obsession and stubborness to accept new technology.

This is essentially because of the difference between analogue and digital signals. Analogue signals are continuous and have varying peaks and troughs, that the audiophiles feel are important to transmit the essence of music. Digital signals, on the other hand is discrete and has limited value variation. Audiophiles complain that there 'could' be a data loss in the first analog to digital conversion itself, as the full frequency variations need to be sampled properly and multiple times. This need sophisticated ADC processors.

When you compress original digital data (such as numbers and letters), the Huffman Code is fairly simple and straightforward. When you use a graphics file, it gets a bit more complicated as you introduce dimensions such as color and pitch. At the same time, graphic files have a lot of null data that can be identified and removed helping in the compression process. But what do you do with a signal that is continuous all the time, has no gaps whatsoever, and one is not sure what the frequency variations (peaks and troughs) are?

In addition to the stubbornness, it is also fear of the unknown.

Have you tried the Squeezebox personally? If so, did you find the quality commensurate with the cost?

I have heard the Squeezebox multiple times, and I have always been amazed at its capabilities and accuracy of rendition. It is definitely on my list of purchases. I am just waiting till I complete my conversion, hoping one may see a more advanced unit from Logitech.

I think the best thing I can do is tell him I lose, let him have his WAV files :) and maybe put a DAC (Beresford good for budget?) between the media streamer and the AVR. If anyone has a better scheme, I'm obliged.

Sounds good to me. And, you are not losing anything. just gaining some knowledge and keeping up with the times. Even John Atkinson who first wrote off the iPod as a piece of junk, has reluctantly included it and the digital format in his 'Audiophile' list. :) Even Deutsche Gramaphone, owner of the best Western Classical recordings in the world has bowed to the times, and has started selling compressed files from its web site. It is unfortunately only MP3 now because of bandwidth issues, but they plan to sell lossless formats soon.

Cheers
 
This is essentially because of the difference between analogue and digital signals. Analogue signals are continuous and have varying peaks and troughs, that the audiophiles feel are important to transmit the essence of music. Digital signals, on the other hand is discrete and has limited value variation. Audiophiles complain that there 'could' be a data loss in the first analog to digital conversion itself, as the full frequency variations need to be sampled properly and multiple times. This need sophisticated ADC processors.

When you compress original digital data (such as numbers and letters), the Huffman Code is fairly simple and straightforward. When you use a graphics file, it gets a bit more complicated as you introduce dimensions such as color and pitch. At the same time, graphic files have a lot of null data that can be identified and removed helping in the compression process. But what do you do with a signal that is continuous all the time, has no gaps whatsoever, and one is not sure what the frequency variations (peaks and troughs) are?

In addition to the stubbornness, it is also fear of the unknown.

The problem ain't the digital process itself. There is mathematical proof for the sampling theorem and in theory any signal sampled at its nyquist frequency or higher can be reconstructed exactly.

However the errors appear not because of faulty underpinning in theory but rather the way ADCs and DACs are implemented. They have their limitations due to engineering and also because of tolerances of passive circuitry which is needed for input output. Every electronic component is an engineering exercise and as hard as you may try, you'd never reach the mathematical precision of what is postulated by theory.
 
Hello the experts,

I need to revive this thread to solve my problem with wav files.

I have a Sony PCM-D50 portable recorder (details available on the pro Sony webpage) that records only in wav format on memory (in-built) and also on memorystick pro. It can record upto 24 bit / 96 kHz which is considerably better than the CD format (16 bit / 44.1 kHz). The recorder is a professional piece of equipment for portable recording. It comes around USD 500 or a bit less in the US market.

I am recording a lot of live music with it at the best quality and do not want to make CD's out of them because CD quality is clearly inferior (can clearly make that out). As a result, I am storing them in my macbook pro for the moment. Since an hour of 24bit/96kHz recorded music is about 1.5 GB of uncompressed wav data, I am thinking of buying external HD storage (250 GB available at 5.5 K). Through a software called "audacity", I can play the music in my macbook pro. ( iTunes can play them as well. However, I am not sure if itunes is playing the 24/96 format or the usual cd format. The analog circuitry of macbook pro is not good enough for me to be able to decide on this from my AKG headphones).

By the way, using the 3.5mm analog stereo out of the Sony PCM-D50 I can also play the music directly from the recorder using my NAD amp. Through the amp the distinction between the 24/96 and 16/44 is very very clear.

But now since I have recently bought the Cambridge Audio 740c CD player which has two excellent DAC's and has 2 digital (both coax and optical) inputs and hence can be used as a separate DAC machine, I want to go the obvious step forward. That is, I want to play the 24 bit/96 kHz music from my macbook pro while the optical out of the macbook pro is connected to the optical in of the 740c . The 740c's two DACs will be in work to make the analog conversion and then the analog signals would be sent to the amp.

Moreover, my CD player has upsampling feature upto 24bit/384 kHz and all this is making me kind of excited about digital sound being close to pristine analog music.

My question is: Does the above scheme make sense? To be more specific, should I be careful about the grade or quality of the optical cable that will be able to carry the 24/96 wav data without trouble? If yes, what is it that I should look for in an optical cable?

My problem here is that I can find some decent optical cables with decent TOSLINK connectors here in Kolkata. However I need a TOSLINK-to mini TOSLINK adapter for the connection to my macbook pro or the Sony PCM-D50 and I cannot find such an adapter in any of the stores, although in the net (for example, amazon) you get such an adapter for 2 dollars.

My other question is: I have a old Sony DVD player which we use for movies on our 37" SONY Bravia LCD TV. We got the video connection thru a ProfiGold component connection and that's good enough for us. However for sound we connect the audio analog output to to our stereo amp. Now with the CA 740c's DAC capability, we can also connect the digital audio out of the DVD player into the digital in of the CA 740c and let the better DAC's in work. That way movies will sound better too, albeit in a 2-channel format (but that's again good enough for us). The question is , should we use a coax cable or optical cable for this purpose? (Both connections are possible in the equipments).

Experts, please help me out.

Regards,
Asit
 
I want to play the 24 bit/96 kHz music from my macbook pro while the optical out of the macbook pro is connected to the optical in of the 740c . The 740c's two DACs will be in work to make the analog conversion and then the analog signals would be sent to the amp.

My question is: Does the above scheme make sense? To be more specific, should I be careful about the grade or quality of the optical cable that will be able to carry the 24/96 wav data without trouble? If yes, what is it that I should look for in an optical cable?

Your proposed method is sound. I see no problem with that.

A Optical cable from any well known company such as Monster, VDH, QED, etc, will serve you well. A 1.5 meter cable will cost you around Rs.4000. VHD's Optocoupler Mark II is an excellent cable that has special spherical lenses at the two ends to focus the light beams. If you read my article on Connectivity (http://www.hifivision.com/audio-video-cables/2608-avr-connectivity.html) I have explained how a bent cable will force the light beams to bounce off the tube''s walls. Though there is not too much harm is this, reputed manufacturers try to reduce the bouncing and create ways for the light beams to travel in a straight line.

My problem here is that I can find some decent optical cables with decent TOSLINK connectors here in Kolkata. However I need a TOSLINK-to mini TOSLINK adapter for the connection to my macbook pro or the Sony PCM-D50 and I cannot find such an adapter in any of the stores, although in the net (for example, amazon) you get such an adapter for 2 dollars.

Does Kolkatta have the equivalent of a electronics market? That will be the best place to search for the adapter. I can try here in Chennai and see if I can get the adapter for you.

The question is , should we use a coax cable or optical cable for this purpose? (Both connections are possible in the equipments).

Asit, for short runs there is no difference between the performance of a optical and co-axial cable, provided if course, that both are from a reputed company. You can use either one happily. I have personally tried a DAC co-axial and a VDH Optocoupler. In extended hearings across the same music, I could not make any difference. Please read the following links for more details:

http://www.hifivision.com/dvd-playe...rders/1788-coaxial-digital-audio-outputs.html

http://www.hifivision.com/audio-video-cables/1666-coaxal-cable.html

Cheers
 
Hi Venkat,

I really cannot thank you enough for your reply, very informative and to the point.

In Kolkata, there is a ProFx store which has QED optical cable at about Rs 2500/- for 1m length. Would that be good enough? As far as I could find, the VDH cable is not available. Is it available in Chennai? The Onkyo store (Promises Instruments) usually has some Monster and Audioquest cables. How good is Audioquest? I'll enquire there.

One problem is that to avoid too much bending, perhaps I should use the length a bit more than the 1m.

About the elctronics market, yes there is a Chandni market here in Kolkata, but there I could not find the TOSLINK to mini-TOSLINK adapter.

I have another question on the possible connection between my cheap DVD player and the azur 740c. As it so happens, the two payers are now sitting one on top of the other at the moment and unless we move to a new place (which will happen in a couple of years) this configuration is not going to change substantially. Because of this proximity of the two players, an optical cable would have to be bent a bit to make the connection. In that case, would a 1m length of optical cable still work satisfactorily? What do you think?
Regards
Asit
 
In Kolkata, there is a ProFx store which has QED optical cable at about Rs 2500/- for 1m length. Would that be good enough?

The length of the cable depends upon the distance between the two units you are trying to connect. Yes, 1 to 1.5 meters is a good length. And yes, QED, Audioquest are all good brands.

As far as I could find, the VDH cable is not available. Is it available in Chennai? The Onkyo store (Promises Instruments) usually has some Monster and Audioquest cables. How good is Audioquest? I'll enquire there.

I bought the VDH from Dubai. In India, VDH is distributed by

Innovative Information Technology Pvt. Ltd.
1507, Maker Chamber V
Nariman Point
BOMBAY 21
INDIA 400 021

Phone: + 91 22 5 632 5010
Fax: + 91 22 5 630 1209
Email: [email protected]

Please call them for more details.

One problem is that to avoid too much bending, perhaps I should use the length a bit more than the 1m.

There will always be some bending here and there. This is acceptable. What you must avoid is multiple twists and the cable forming an 'x' in some places, or an '8 elsewhere. Keep it as straight as possible with one or two gentle turns. Also remember, at the connection point, an optical cable is a little stiff because of the TOSLINK connector. Giving it it a little lead there so that the connector is not twisted is a good idea.

I have another question on the possible connection between my cheap DVD player and the azur 740c. As it so happens, the two payers are now sitting one on top of the other at the moment and unless we move to a new place (which will happen in a couple of years) this configuration is not going to change substantially. Because of this proximity of the two players, an optical cable would have to be bent a bit to make the connection. In that case, would a 1m length of optical cable still work satisfactorily? What do you think?

I would not recommend keeping anything on top of a expensive CDP such as the 740C. Keep it on the topmost rack of your AV system so that there is noting on top of it. As I said before, the bends you will get when you connect two units near each other will not affect the connectivity.

Cheers
 
Last edited:
Thanks again, venkat.

One more question: The DVD output is 5.1 or 7.1 or something (meaning it's not 2 channel stereo). Now when I connect the audio output of the DVD digitally to the input of the 740c which can act as a DAC only for 2 channels, what will exactly happen? Will the 740c be able to reduce the music to 2 channels and then put them thru the two DACs for the analog conversion? (When I am connecting the DVD audio out to the input of the amp, I am using 2 analog connections for the 2 channels, that is, the DVD already has a mechanism inside it to reduce the multi-channel audio into 2-channel audio)

I am sorry for asking too many questions and you are very kind to answer, but somehow (beyond one of my material interests of improving the movie sound) I am finding these issues quite interesting.

By the way, why do you think I should not put anything on top of the 740c, is it because of resonance issues of the boxes?

Regards
Asit
 
The DVD output is 5.1 or 7.1 or something (meaning it's not 2 channel stereo). Now when I connect the audio output of the DVD digitally to the input of the 740c which can act as a DAC only for 2 channels, what will exactly happen? Will the 740c be able to reduce the music to 2 channels and then put them thru the two DACs for the analog conversion? (When I am connecting the DVD audio out to the input of the amp, I am using 2 analog connections for the 2 channels, that is, the DVD already has a mechanism inside it to reduce the multi-channel audio into 2-channel audio)

Logically you are correct. When a proper processing of the Dolby or DTS signal is done by the DVD Player or the receiving unit, 5.1/7.1 signals are down mixed into 2 channels with a slight gain attached to surround channels. The center channels is divided equally into the L&R channels so that even in stereo it looks as if the dialogues are coming from in between the speakers. Dolby and DTS signals have what are called metadata that instruct the software on how the down-mixing is to be done.

But when you send a Dolby/DTS signal in digital form and receive it by a processor that does not understand the data - I am not sure what will happen. I feel all channels other than the Front L&R will just be truncated.

DVD-A and SACD signals are supposed to carry information that is exact duplicate of the HD signal but in stereo. But Dolby.DTS only have metadata for down mixing.

By the way, why do you think I should not put anything on top of the 740c, is it because of resonance issues of the boxes?

Both are electromechanical devices and would have some vibration. In a CDP player such as the 740C, the drive is right on top, and any pressure on top could affect the drive. Ambient resonance of any kind could create jitter when the CDP is being played. This is my opinion. But I have read that a lot of audiophiles go to extraordinary lengths to make a CDP completely vibration free. At home I keep the electromechanical devices independent of other equipment even if it means additional lengths to the interconnects.

Cheers
 
Hi Venkat,

Although this is outside the topic of the thread, I have now rearranged the components in my set up so that nothing's on top of the azur 740c, it's sitting alone. Thanks for the detailed tips.

After your last reply, I am not too sure if at all I would connect my DVD player's optical out to the optical-in of the 740c. I have read the manual, and it does not say anything to encourage me. Actually the manuals these days are very disappointing and the equipment looks like a black box.

I am still looking for the TOSLINK to mini-TOSLINK adapter for digital (optical) connectivity of my macbook pro and pcm recorder with the 740c.

Regards
Asit
 
I am still looking for the TOSLINK to mini-TOSLINK adapter for digital (optical) connectivity of my macbook pro and pcm recorder with the 740c. Regards Asit

I will look around in some shops in Ritchie street over the next few days. In case I am able to get it, I shall get your address and courier it to you.

Cheers
 
Hi Venkat and anybody else interested,

I registered with CA customer care this afternoon and sent in a query. Within about half an hour I got the reply.

My query:
.... What will happen if the digital output of a DVD 5.1 or 7.1 audio is sent to the digital input of the azur 740c? Will it be able to process the data (that is down-mix it to 2 channel stereo audio and then D/A conversion etc)?

CA response:
Dear Asit,
Thank you for your email.
The 740C as a CD player is designed for 2 channel use. The up-sampled outputs are 2 channel.
As such, the digital signal from the DVD player must be 2 channel for the 740C to recognise and up-sample it.
You need to set the downmix to 2 channel to happen in the DVD player, and output this signal to the 740C.
I trust the above information is of assistance to you.
Regards,
Ben Beaumont.

Impressively quick response. Don't you think?
 
As such, the digital signal from the DVD player must be 2 channel for the 740C to recognise and up-sample it. You need to set the downmix to 2 channel to happen in the DVD player.

Good, my thoughts were correct. The 740C will not recognise more than 2 channels.

Can you set your DVD player to down mix to two channels?

Cheers
 
After a lot of search the whole evening yesterday, I could not find the user manuals of the DVD player (Sony DVP NS 50P), although detailed documentation of everything else bought two decades ago in different continents showed up. I guess I never cared much about this DVD player.

But now it mattered, so I dug the manual up from the Internet. It's a 72 page very detailed write-up describing all kinds of settings one could imagine.

And yes, it also had what I was looking for. Apparently the digital coax out is already set up by default with downmixed 2-channel audio. I also have the choice to use with simulated surround (default) or just stereo, both 2-channel.

All it requires of me is to go out and buy a decent coax cable which is quite possible here in Kolkata. For the laptop and PCM recorder, I still need the optical cable and the adapter.

I have not read enough of the manual to find out what's the use of the optical digital output port of the DVD player.

Never had much respect for this player, and naturally it collected the most dust among all our AV equipments. I am going to give it a nice clean-up job one of these days and I have already started covering it with a nice matching piece of soft cloth since last night.
 
The DVD Player must be feeling good, eh? Suddenly it's master has new respect for it - like the return of a lost lover? :) I am sure it will be happy and serve you well.

Cheers
 
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