Digital audio s pdf. Connecting and setting up SPDIF-HDMI audio on a computer

Digital interfaces have long been pushing aside their analog ancestors. Middle-class audio systems use sound encoded in one of many standards as a signal source. This could be banal PCM for stereo sound or the Dolby family of standards for their multi-channel relatives. But today we will not talk about encoding methods, but about how exactly the signal is transmitted. There are only two options - optical and coaxial cable. The optics guarantee complete electrical isolation, the coaxial cable is easy to connect.

For ten years now, almost every motherboard has been equipped with an optical digital output S/PDIF (aka TOSLINK). But if you look at the back panel you can’t always find it. What's the catch? The manufacturer does not want to install another connector on the rear panel and increase the cost of the board by installing an optical module or a socket for a coaxial cable. If you open the documentation for the motherboard, you will find a typical set of four contacts similar to a socket for connecting a speaker.

On the same page there is a branded strip with coaxial and optical outputs. Sometimes there are also optical inputs, but the author of the article only read about this on the Internet. Finding an original plank can turn into a non-trivial task - the price at foreign auctions is about $10, excluding delivery. A quick search on Russian-speaking forums finds only requests for its purchase and advice to buy a sound card with the appropriate socket instead.

According to the specification, the signal level on the motherboard is TTL; we can only guess about the load capacity of the SPDIFOUT output. The same documentation recommends loading it with an LED with a current-limiting resistor - this will be the cheapest connection. I didn’t dare try this option first for two reasons - I was sorry for the board and the urgent need to plug a standard optical cable somewhere. Later, I nevertheless assembled an emitter follower on one transistor and connected an LED. The interface glowed cheerfully with a red LED, but the optical cable attached to it did not produce sound. The same documentation recommended choosing an ultra-bright LED with a wavelength of 660 nanometers. Perhaps none of the LEDs used were suitable.

The next step is to connect the recommended TOTX173 optical module. The price and availability in online stores are again not encouraging - a little less than the same ten dollars and long delivery. So it's time to look for a donor. After going through the electronics dump at home, we were able to identify only one victim; it turned out to be a Playstation 2, given by employees for their last birthday. No hand was raised against the vandalism of the legendary console. At a regional online auction, a Samsung DVD Recorder was caught for the same sacred $10 without delivery. Photos will follow.

S/PDIF on the victim looked like this

Since a search using the code on the case (T2002H7) did not yield anything, the device had to be turned on in a disassembled state to make sure that it was using a five-volt power supply and a TTL signal level.

There are only three contacts, the common one is easily identified, the power is connected directly to the signed 5V plug, leaving the information output connected through a 220 Ohm resistor. Here's a close-up of our newfound module.

All that remains is to connect to the motherboard and assemble it all in the form of a bracket. We connect the common pin to common, power to power, and SPDIFOUT through a 220 Ohm resistor to data. We assemble a PC bracket from a piece of a breadboard and a burnt-out network card, this is what I did.

We install it in the case.

More than two weeks have passed since the installation - everything works perfectly. By ear, of course, the difference is within the limits of the sensations given by psychology. But if there is acoustics that understands optics, why not use a connection made by yourself. In the comments, it would be interesting to hear an opinion about the possible difference in the sound of such an optical output and that obtained from a mid-price range sound card.

After assembly, I made my way to the nearest appliance repair shop. It was there that we should immediately look for a donor - they have a sufficient number of burnt-out DVD players, for about a dollar per fee. For those who want to repeat the design, this will be useful.

958 type II in the international standard IEC-60958). It is a collection of low-level protocol and hardware implementation specifications that describe the transmission of digital audio between various components of audio equipment. When describing S/PDIF, it is necessary to describe both the physical part (that is, how the signal is transmitted and why) and the software part (that is, the protocol used).

S/P-DIF is the consumer version of the standard known as AES/EBU; has slight protocol differences and requires less expensive hardware.

Areas of use

S/PDIF was originally used in players (and DVD players that play CDs), and then became a common way to connect and transmit audio in other audio components, such as MiniDisc players and sound cards for personal computers. It has also gained popularity in car audio, where the former clutter of multiple wires can be replaced by a single fiber optic cable that is resistant to electrical interference.

Another application of the S/PDIF interface is in the transmission of digital surround sound as defined by the IEC 61937 standard. This mode is used to connect the output of a DVD player to the input of a home theater AV receiver that supports Dolby Digital or Digital Theater System (DTS) surround formats. sound.

S/PDIF (Sony*/Philips* Digital Interface) is an audio interface format that supports the transmission of digital audio signals from one device to another without conversion to analog, thereby avoiding degradation of sound quality.

For SPDIF, 192-bit words are divided into 12 words of 16 bits each. The first 6 bits of the first word are the control code; the meaning of these bits is shown in the table:

Other

S/PDIF is defined by the international standard IEC 60958-3.

Notes

Bibliography

J. Watkinson The Art of Digital Audio, Third Edition, Focal Press, 2001

Wikimedia Foundation. 2010.

I have no sound on windows 7, I have no experience in troubleshooting such malfunctions in this operating system, but I really want to figure out what’s wrong and fix the problem myself. You have a similar article about Windows XP, but unfortunately it didn’t help me. Denis.

No sound on Windows 7

The reasons for the lack of sound in Windows 7 are sometimes simple, and often it takes quite a long time to find the problem. Very often, when asking a question, users do not provide complete information about the problem, for example, they do not say that they tried to update the sound driver the day before, or tried to connect other sound speakers to the computer, or made changes to the settings of the “Sound” tab in the Control Panel. Or maybe you installed some plugin on your laptop to improve the sound quality of the players installed on your system and after that you no sound on windows 7. But no matter what happens to you, friends, do not despair, there is a solution to your problem and, as usual, we will start with the simplest.

Note: at the end of the article, as an option, there is a way to work with a little-known to a novice user - Universal diagnostic tool for Windows 7, it can automatically find and fix various problems related to more than just no sound. We have also published a new article, in which you can learn in detail how to set the exact name of your sound card, how to download drivers for it from its official website, and how to install them.
If you have Windows 8, read our article
If your built-in sound card has failed, read our article.
If you are not satisfied with the sound quality on your laptop, you can.

Even very experienced users have situations when, for some reason, they disconnected the sound speakers from the system unit and then forgot about it. Check that everything is securely connected. The output for connecting audio speakers is marked green.

You can check the serviceability of the sound speakers by connecting headphones to the sound output; if there is sound, then the speakers are faulty. Also, if there is no sound in Windows 7, you need to go to the device manager and pay attention to whether you have an exclamation mark in a yellow circle next to the Sound devices item. Start->Control Panel->right-click on “Computer” and select Properties from the menu, then Device Manager. If the yellow circle is present, then your sound driver has simply crashed and you need to reinstall it again.

How to do it? Read our article How to install a sound driver(link above), but on the other hand, the sound driver just doesn’t crash, which means that some of your actions led to the problem, by the way, Windows 7 has a system restore service, which you of course know about, so you can use it in this case.

Note: In order not to rack your brains over which of the two hundred programs and games you installed yesterday led to sound problems, you can use a simple system restore, fortunately in Windows 7 it is usually turned on for everyone and roll back a little.

Just yesterday, my friends asked me to fix the problem of no sound on their computer. The day before, for some reason, they downloaded and installed two multimedia players on the Internet at once, after which they lost sound. First of all, I looked at the speaker volume indicator in the Taskbar to see if it was completely turned down, but everything turned out to be fine.

I also right-clicked on the Speakers button and selected Playback Devices from the menu.

At the Dynamics item there was a green check mark as expected.

Although sometimes when there is no sound in Windows 7, the Sound window displays only Digital Audio (S/PDIF)

or absolutely nothing is displayed, then click on an empty space with the left mouse button and a menu will appear in which you need to check two items “Show disconnected” devices and “Show disconnected devices”

and we will immediately see our Speakers, right-click on them and select Enable.

We do the same with headphones, then “Apply” and “OK”.

It’s strange, but for my friends, the Sound window displayed Speakers marked with a green checkmark and in the device manager there was a working sound device with support for NVIDIA High Definition Audio

Everything indicated that the sound was fine. I brought headphones with me and connected them to the sound output located on the back of the system unit and made sure that there was actually no sound, which means the sound speakers were also working.
The first thing in this case is that the sound device driver may be damaged or not working correctly, which means you need to go to the device manager and try to update the driver, which will not always help, in this case you need to completely remove all sound devices from the system.

After the operation was performed in the operating system, my friends started hearing sound. By the way, in this case, you can also use system recovery and, of course, a complete reinstallation of the driver.
Another time there was a different problem, a person installed Windows 7 on his computer, everything would be fine, but there was no sound, there was eloquent information in the device manager.

In such cases, you need a disk with drivers for the motherboard that came with your computer when you purchased it. On this disk you need to see whether the drivers on it are suitable for Windows 7. If the drivers on the disk are intended for Windows XP, naturally you should not install them, you need go online and download native drivers for your sound card on its official website.

How to do this is written in detail and step by step in the article. Often, not only searching for drivers, but also correctly determining the name of the device is a problem for a novice user, so I still advise you to follow our link and read the article. If you still don’t find a driver for Windows 7, but you have an installation package of drivers for Windows XP, you can try to install it in the Compatibility Troubleshooting mode, but I’ll tell you, friends, this is not exactly the best option.

It happens that it is not possible to find the reason for the lack of sound at all; if the built-in audio card fails, in the device manager there may be a red circle with a cross next to it, or there may be nothing, in this case, many decide to completely reinstall the operating system, then install it on the sound card drivers and if in this case the sound does not appear, you just need to buy and install a separately installed PCI interface sound card. It is advisable to buy it together with a disk containing drivers specifically for your Windows 7-64bit or 32bit. You also need to know that immediately after you have installed a separate PCI sound card in the system unit, the built-in one in most cases must be disabled in the BIOS, otherwise the sound will not appear. Many people do not attach importance to this, and in vain. High Definition Audio should be set to Disabled.

A simple PCI interface sound card is not expensive at all, about 100-200 rubles, and for example, I always carry it with me. The first signs of failure of the integrated sound card are occasional missing or low-quality sound. This means it’s time to replace it with one installed in the form of an expansion card.
By the way, individual PCI interface sound cards are different, for example Sound Blaster manufactured by Creative Technology, are essentially a very high-quality and professional solution, but cost from two thousand rubles.

But keep in mind that if you have such a card, as well as a good audio system, and in some game you decide to shoot with a Kalashnikov assault rifle, your neighbors may misunderstand this and decide that you are actually firing at houses with a machine gun.

An interesting story about how we searched for the missing sound with our reader.
Denis wrote me a letter saying that he had no sound on windows 7-64bit, suspicion of a faulty built-in sound card. The sound speakers are missing, they were checked on another computer and they were fine. Reinstalling Windows 7 and installing native drivers from the disk on the motherboard that was included when purchasing the computer did not help. Also, the downloaded driver package from the official Realtek website did not bring any results after installation.

Our reader bought and installed a sound card installed separately in the PSI connector; before purchasing, he inquired whether there was a disk with drivers for Windows 7-64bit for it. Next comes the most interesting part: he puts the side cover of the system unit in place, then connects all the cables and sound speakers, and turns on the computer. I remind you that the sound card came with a disk with drivers, which it successfully installed, but the sound did not appear. He wrote me 10 letters, we sorted out all the faults that could be there, but the sound still did not appear, I began to have thoughts that the purchased sound card was also faulty, this happens or it is not fully inserted into the PCI connector. Denis, at my request, took the card to the service center where he bought it, where they checked it in front of him and it turned out to be working.

In his last letter, Denis sent me a screenshot of the system unit and showed me his mistake, it turns out that he still connected the speaker cable to the old built-in faulty sound card, like this. Our reader’s system unit was under the table and our friend, according to him, had to act literally by touch. It’s not surprising that he made such a mistake and he can be forgiven for it, since you’ll agree, friends, in the absence of experience, the chances of connecting the speakers incorrectly increase greatly. So I ask you to take all of the above carefully.

The arrow shows the sound output of the purchased audio card, the place where the speaker plug needed to be connected; on top you can see the same connector, only belonging to the failed built-in sound card.

Universal Windows 7 Diagnostic Tool

As I promised, I will give an example of working with the Windows 7 Universal Diagnostic Tool, let's try to use it to fix the problem of no sound in Windows 7.
Control Panel->System and Security

Support Center

Maintenance and Troubleshooting.

As you can see here, you and I will be able to solve many problems that arise, and not only with sound. Equipment and sound.

Play sound.

USB cable 120cm long

Optical cable 1M long

The ends are covered with rubber protective caps.

The connector is standard SPDIF with beveled corners.
Many of you, like me, have sometimes seen it on TV and some computers, but have never used it, so it will be interesting to find out what kind of beast it is.

There is an optical fiber inside, if light is applied to one end, it can be removed from the other end.

And finally, the converter itself is a metal box with connectors on both sides.

On one side there are inputs: power and digital audio, either via an optical Toslink cable like ours, or via a coaxial one.

On the other side, there are outputs: 3.5mm headphone output, two RCA tulips and a power indicator, red and quite vigorous.

The dimensions of the converter are small: 5.5cm*6cm*2cm
But it is quite weighty thanks to the metal body: 82g

The converter is easy to disassemble, just unscrew the screw.

And then two more and you're done:

The work at the back is a little sloppy, the soldering is ugly in places, and the flux has not been washed off in some places.
I'll give you close-up photos:
http://s19.postimg.org/42zggy8tv/audio_converter_19.jpg
http://s19.postimg.org/bmsjj020j/audio_converter_20.jpg
http://s19.postimg.org/o05dpwroz/audio_converter_21.jpg
http://s19.postimg.org/fkft8eotv/audio_converter_22.jpg

Well, let's connect.
The connection is incredibly simple, insert the necessary wires where necessary and power it from the USB of the TV itself.
The indicator is eye-catching, like a mini flashlight.

It’s better to turn it somewhere back into the wall or completely seal it, since at least when the TV is turned off, it’s also turned off.
In the TV settings, in the sound section, you can choose where to output the sound; on Samsung, the fastest way to get there is through the quick settings button.

If the audio output is selected as in the screenshot, then the sound in the TV itself no longer comes, and when we try to adjust the volume it will write that we have tuned in to external speakers and now we must adjust the sound with their remote control.

You don’t have to switch the sound to external ones, they always play as soon as they are plugged in, then both external and internal speakers will play at the same time, and in many cases there will be an echo due to the time it takes to convert digital to analog, a kind of hall effect.
You can mute the built-in speakers or reduce their volume to zero so that the muted speaker icon does not appear on the side.
But when watching especially multi-channel films, it is better to use both speakers; the TV transmits mid-frequencies well - speech, music. the center acts as a sub and provides special effects.
During operation, the converter practically does not heat up.

I don't have a professional microphone, so I did my best with a regular camcorder to convey to you the difference in sound between the built-in speakers and external ones.
In reality the difference is even higher than in the video.
You will need bass headphones or speakers to hear the difference; you are unlikely to distinguish anything in laptop speakers or desktop plastic tweeters.

That's all, thank you all for your attention.

S/PDIF on the victim looked like this

We install it in the case.

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