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How many audio channels over 1 pin spdif ? (x-fi)
Hello,
Take a look at this picture, it shows pins for audigy and x-fi elite pro soundblasters: http://pinouts.ru/visual/gen/sb_audigy2_ad_ext.jpg ascii version in case picture is no longer available: 2 40 ..................... ..................... 1 39 pins seem to be numbered vertically from bottom to top 1, 2, then next column is probably 3 4 and so forth. Not sure which pins would be important to make a custom cable. pin 5 spdif 0 in pin 9 spdif 0 out pin 27 spdif 3 out pin 29 spdif 1 out pin 31 spdif 2 out Which other pins would be important ? It mentions these SPDIF output pins. 0,1,2,3 So that's 4 pins. How many audio channels can travel over 1 pin ? Also how would these be connected into a cable, should gnd be included or another other pins What I am trying to figure out if the X-Elite Pro soundblaster is what I currently believe it is: 7.1 Surround Sound Analog outputs 5.1 Surround Sound Digital outputs However if only 4 spdif pins available then how would it achieve 6 channels for 5.1 surround sound digital ? I read somewhat 1 spdif connection via normal connectors/cables can carry two audio channels. So this ad_ext connector has 4 spdif pins, is the x-elite pro soundblaster perhaps a 7.1 digital output device after all ? But hampered/nerfed/capped by cable design ? Currently I am investigating sound quality of laptop/hdmi digital vs dreampc2006/x-fi analog both to same receiver (denon 1909). The digital connection from laptop is remarkable... it produces very high quality sound, sharper/more so than the x-fi analog signals. So I am very interested in trying to connect the x-fi digitally. I will most likely purchase spdif cables fiber optic and coax from a local shop if they have it and they probably do. I will purchase these mostly to see if there is indeed a big quality difference in audio signal between analog and digital from x-fi. I am starting to believe this is indeed the case.. So even testing x-fi 5.1 surround sound would be interesting to see quality differences. Currently the laptop hdmi receiver setup is not producing surround sound correctly. This is probably caused by the receiver being in 7ch stereo mode which is wrong. This simply duplicates a stereo signal over multiple speakers which is wrong I believe. For example the "rear right" signal can also be heard on the "right speaker" this is wrong, the "rear right" signal should only be heard on the "rear right speaker". I think I know how to configure the receiver to select/set a different surround mode, it may have to be channel direct, or perhaps dolby digital ext/plus that sort of thing. I will experiment with that tomorrow to see if correct surround sound can be produced from the laptop via hdmi to receiver. This annoyed me when playing world of warships or company of heroes on the laptop... the direction of sound didn't seem right at all, so it was noticeable. I must say the x-fi elite analog setup worked much simple straight out of the box into the receiver basically, so for noobies the analog setup is much easier to get working correctly. Creative was smart to seperated the 8 channels into 4x2 stereo signals... the receiver I think sends this forth to the speakers. However this signal is probably not digital hence some signal loss from digital to analog convert and back to analog to digital convert dac/cad Today I spent many hours doing experiments and getting to know my receiver better and being able to configure it with just the 1 or 2 line display on the device itself instead of on screen display connected to monitor... cable probably too short anyway but I also wanted to learn to operate this device from itself without any other devices. I kinda like these technical challenges, guess it's my experience and age and mindset/determination to get it working, "failure is not an option" mindset from playing all that world of warships lol. Also my x-fi elite pro came with this breakout box as I called it or as some call it official name now is i/o console. It also has spdifs... but only two spdifs out... So are these the 4 pins from the ad_ext going to the breakout box ? forming two spdif outputs on it ? What I also wonder about is the "flexi-jack" it can also be configured as an digital i/o. Probably a spdif output. It can work via RCA to mini cable or something like that. So is this again the same 4 pins, perhaps 2 of them going /inout of that flexi jack ? Or is this yet 2 additional spdif pins ?!?!?!? So what is the actually ammount of spdif output pins/channels that this x-fi elite can do ? Is it only 4 spdif pins output ? Or is some whacky combination of: ad_ext 4 spdif pins + digital i/o flexi jack possible ? Perhaps resulting in a hardware/connection-wise output possibility of 6 spdifs outputs ?!? Let's assume for a moment that this would be possible, would theoretically this be enough for 7.1 channels ? Or are 8 spdif pins neccessary for that ? So this is where I am somewhat confused ? Perhaps 3 signals can go over a 2 pin spdif output connector thanks to dolby/dts compression ? How does that work ? Same question as in beginning but kinda filling in the possible blanks here myself... which could be totally incorrect. Bye for now, Skybuck. |
#2
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How many audio channels over 1 pin spdif ? (x-fi)
wrote:
Hello, Take a look at this picture, it shows pins for audigy and x-fi elite pro soundblasters: http://pinouts.ru/visual/gen/sb_audigy2_ad_ext.jpg ascii version in case picture is no longer available: 2 40 .................... .................... 1 39 pins seem to be numbered vertically from bottom to top 1, 2, then next column is probably 3 4 and so forth. Not sure which pins would be important to make a custom cable. pin 5 spdif 0 in pin 9 spdif 0 out pin 27 spdif 3 out pin 29 spdif 1 out pin 31 spdif 2 out Which other pins would be important ? Start with Wikipedia. https://en.wikipedia.org/wiki/S/PDIF You should use the proper "accessory" with your sound card. If there is a front panel accessory, a box with a ribbon cable intended for that connector, then use it. SPDIF is digital. It runs at 6MHz. It can carry stereo (two channels). It can carry encoded content (AC3) which unpacks to 5.1 sound. It can also carry four channels without coding, but the resolution uses half the bits. I've never seen any practical examples of the four channel mode being used (no one is crazy enough to use it). From a quality perspective, only the two channel mode is worth using. I've never noticed any AV receivers in my travels, with four SPDIF inputs, so I don't know why they'd have four of them like that. Perhaps some Creative product has four SPDIF inputs ? ******* If you're a hardware hacker, there are at least three ways to send the signal. 1) The proper way, is transformer isolated, 0.6Vpp. 75 ohm coax cable, RCA connector perhaps. Home theater systems or older AV receivers, might use the proper interface. Transformer isolation (similar to what Ethernet uses), removes grounding differences as an issue. I think we had a discussion once, about the abnormal grounding in your place. 2) The signal on the 40 pin cable, could be 3.3V TTL levels. It might not be intended for driving a 75 ohm coax cable directly. That's why you'd want to see the circuitry on the Front Panel board for the sound card. A circuit is needed to convert the signal on the 40 pin, into something the AV receiver can use. It would be typical to put the "cheapest" signal on the connector, and then the device receiving the signal (the Front Panel board) is responsible for conversion into a proper signal. 3) Converting the 3.3V signal to TOSLink using a $1 LED transmitter, is typically the best means of delivering the 6MHz digital signal. The TOSLink plastic fiber optic cable solves the ground loop problem. With four S/PDIF you could send 8 channels in good resolution. But I've never seen such a thing done with audio equipment. No pictures of such. ******* You're delusional if you think the SPDIF receives a different signal than the analog channels do. When you use the analog channels, you are using the Creative DAC chips, whatever they used for conversion of the digital signal to analog. They're probably damn good DACs. That's probably not the weakest link. The worst part of a Creative product, is the DSP treatment of the audio, before it's sent anywhere. One other poster referred to this as "digital mutilation". That's because they do stuff like add echo/reverberation, to give "depth" to the signal. You should not do that to all music types. Applied to a piano recording for example, the results could be "muddy" sound. Some sound card drivers, the "Special Effects" setting of "None", doesn't work. A test shows the card is still adding concert hall reverberation effect to the output signal. This is the part you need to get rid of. I only studied this, because the sound I was hearing was muddy. Sending test signals using Audacity on one computer, and recording the analog output via LineIn on a second computer, is how I discovered the "Special Effects" were still enabled. It's not the DACs on the Creative card, but it could be the reverb. That would be just one example of "mutilation". Paul |
#3
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How many audio channels over 1 pin spdif ? (x-fi)
On Sat, 24 Nov 2018 03:44:33 -0500, Paul
wrote: They're probably damn good DACs. That's probably not the weakest link. - Many more MBs have audio chipsets that are now to where standards equal to the dedicated soundbaord, rendering it redundant from a baseline perspective of audiophile-grade stereo signals. There is also that same issue with another board, I use, adding native chipset reverberation delays. It took an OEM driver utility to fix and turn it off. I really can't place a developer's mind, when the driver and utilities include, usually for the only effects, several reverberation-class delay parameters, randomly labeled as much for "features", even with an audacity to title one such for a "Sewer Pipe". Probably because an average user wouldn't go much beyond a minimum to reproduce sound from a MB's soundchip. Somewhere between what's allowable as "cute", and bold package lettering for advertising the MB's audio performance. Consequent software audio and DSP modules may then mean little if anything -- so a "Sewer Pipe" it is, as far as the purchaser will go; ... who's could not then care if, at a driver-level or minimum install, in addition, that a delay is effectively hardcoded. Or that Creative, given existing interests to include an OEM support with the resources to turn off an aesthetic appeal for discerning listeners, to concordantly murmur over a toilet-bowl being flushed. Then again, the software, specifically, made my one and only Creative Labs soundboard, a first choice to buy one, my last upon gratefully replacing it with a Xonar series. I use quad-duplicate stereo imaging and an additional TOSlink LED carrier for two more, or six active channels being duplicated over a single stereo source processing;- the TOSlink may be optionally defined for its own sampling rate. There are, additionally, more progressive options for modern theater usages, with dedicated equipment for more channels, although I'm not interested in going there. The TOSlink "seems muddiest", a bass definition for corrective measures to speaker limitations, (rear passive radiators: "drum-skins" in non-ported "Eastcoast" engineering), although a straight mixer input from a DAC unit. That could possibly change with signal rerouting, or auxiliary hardware processing, both compression/expansion and EQ-ing, on each pair of the quads. Notably a bad EQ pot and unacceptable noise from my first attempt to resolder it for a by-pass condition. I'll recheck the soldering and possibly swap a working low-pass filter pot, or I've another piece of Chinese assembled gear that was built to take a crap. Or not: Mixer pathing shouldn't matter for a base duplicity between either soundboard stereo analogue outputs, and the DSP TOSlink's and an assumed fidelity from the inline DAC unit. (The last dedicated EQ, this one replaced, was entirely from a digitally controlled interface screen, no sliders, and had its own dedicated TOSlink input.) |
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