I've been lurking on these forums for the past few years and many people here are quite knowledgeable...

Ok so I have a AuzenTech X-Plosion Cinema audio card hooked up via optical to my Pioneer vsx-516. This card takes multi channel audio from the pc and encodes it into either dolby digital or dts and streams it over optical in real time. My problem is, when I watch dvds, or HD clips from the web, my center channel never plays alone... Also in my sound cards testing mode when the center plays, the left and right play as well. Does any one have any idea how I might go about fixing this? I tried to google for answers but its very hard to phrase.

Update: Using the channel level adjustment tool on my receiver the center plays alone, so perhaps this is a question I should be asking my sound card manufacturer.
Maybe someone here has a similar card though?

This card takes multi channel audio from the pc and encodes it into either dolby digital or dts and streams it over optical in real time. My problem is, when I watch dvds, or HD clips from the web, my center channel never plays alone... Also in my sound cards testing mode when the center plays, the left and right play as well. Does any one have any idea how I might go about fixing this?If a soundtrack is already multichannel it most likely already IS DD5.1 or DTS5.1. The soundcard probably is able to DECODE DD5.1 and DTS5.1 multichannel material for playback. But once decoded, it probably can't send this to the Pioneer via optical, and even if it could, the Pioneer probably wouldn't accept already decoded material. At least not play it back properly. 5.1 material decoded by the soundcard would most likely have to be reproduced by speakers (or something) connected directly to the soundcard's outputs.

Now, if your soundcard is sending a multichannel DD5.1 or DTS5.1 bitstream properly to the receiver, the receiver should be able to decode it. If that is what you are doing, make certain the receiver is set up properly for DD.5.1 or DTS 5.1 decoding and playback. If you happen to be sending already decoded material to the receiver via optical, it is going across as 2-channel PCM to the receiver which will obviously not decode this (it is already decoded) and may instead be applying some sort of DSP (like DPLII or other) to the 2-channel material. If this is what is happening, the center channel material will NOT be discrete, and may indeed be played back along with the L/R channel information. So, make certain you are sending a multichannel bitstream to the receiver for decoding and that the receiver is set up to apply DD5.1 or DTS5.1 to that material.

Also, you need to calibrate the receiver's speaker level trims properly.

If a soundtrack is already multichannel it most likely already IS DD5.1 or DTS5.1. The soundcard probably is able to DECODE DD5.1 and DTS5.1 multichannel material for playback. But once decoded, it probably can't send this to the Pioneer via optical, and even if it could, the Pioneer probably wouldn't accept already decoded material. At least not play it back properly. 5.1 material decoded by the soundcard would most likely have to be reproduced by speakers (or something) connected directly to the soundcard's outputs.

Now, if your soundcard is sending a multichannel DD5.1 or DTS5.1 bitstream properly to the receiver, the receiver should be able to decode it. If that is what you are doing, make certain the receiver is set up properly for DD.5.1 or DTS 5.1 decoding and playback. If you happen to be sending already decoded material to the receiver via optical, it is going across as 2-channel PCM to the receiver which will obviously not decode this (it is already decoded) and may instead be applying some sort of DSP (like DPLII or other) to the 2-channel material. If this is what is happening, the center channel material will NOT be discrete, and may indeed be played back along with the L/R channel information. So, make certain you are sending a multichannel bitstream to the receiver for decoding and that the receiver is set up to apply DD5.1 or DTS5.1 to that material.

Also, you need to calibrate the receiver's speaker level trims properly.



The sound card has two features called dolby digital live and dts connect, these take multi channel sound and encode it into a bitstream that can be transported over optical for decoding by the receiver. My games are working in surround sound, and movies seem to be as well, minus the center channel.

Is there some kind of test video I could use to confirm the only speaker not functioning properly is the center?


Also, what exactly is speaker level trim?

The sound card has two features called dolby digital live and dts connect, these take multi channel sound and encode it into a bitstream that can be transported over optical for decoding by the receiver.I could understand maybe wanting to do this with mono or 2-channel material, but why would you apply this to something that is already encoded in DD5.1 or DTS5.1? :confused: If it is already DD/DTS5.1, just send it natively to the receiver for proper decoding.

Whether this has something to do with your problem or not, I don't know. But I would definitely not apply some sort of pseudo DD5.1 or pseudo DTS5.1 encoding algorithm to material that already is DD/DTS5.1. Why would you?


My games are working in surround sound, and movies seem to be as well, minus the center channel.The games, which are most likely DD2.0, at best, may sound great with these treatments. I would try sending these games natively to the receiver to see what they sound like if the receiver applies DPLII to them. May sound better. But if your movies (or any games) are already DD/DTS5.1, as I said, send them natively to the receiver. They're already encoded in DD/DTS5.1.


Also, what exactly is speaker level trim?A "speaker level trim" refers to the capability to adjust each individual channel's level within the receiver. For a proper surround sound experience it is essential that you adjust the individual speaker level trims properly to ensure that the sound from each speaker arrives at your ears at the correct volume. You also need to set the speaker distances properly. Adjusting the distances and individual speaker level trims (among some other things) is called calibrating your system. There are different ways to go about this. The simplest is to use the receiver's built in test tones or, better yet, if it is so-equipped, use its auto-cal capability. Read the manual for more details.

I could understand maybe wanting to do this with mono or 2-channel material, but why would you apply this to something that is already encoded in DD5.1 or DTS5.1? :confused: If it is already DD/DTS5.1, just send it natively to the receiver for proper decoding.

Whether this has something to do with your problem or not, I don't know. But I would definitely not apply some sort of pseudo DD5.1 or pseudo DTS5.1 encoding algorithm to material that already is DD/DTS5.1. Why would you?


The games, which are most likely DD2.0, at best, may sound great with these treatments. I would try sending these games natively to the receiver to see what they sound like if the receiver applies DPLII to them. May sound better. But if your movies (or any games) are already DD/DTS5.1, as I said, send them natively to the receiver. They're already encoded in DD/DTS5.1.


A "speaker level trim" refers to the capability to adjust each individual channel's level within the receiver. For a proper surround sound experience it is essential that you adjust the individual speaker level trims properly to ensure that the sound from each speaker arrives at your ears at the correct volume. You also need to set the speaker distances properly. Adjusting the distances and individual speaker level trims (among some other things) is called calibrating your system. There are different ways to go about this. The simplest is to use the receiver's built in test tones or, better yet, if it is so-equipped, use its auto-cal capability. Read the manual for more details.

Well I was under the impression that 5.1 channel audio cannot be sent over a toslink cable unless the sound card is able to process the 5.1 over digital with one of these real time encoding methods. I was told that optical out only supports 2 channel PCM, except of course with sound cards with chips onboard like this one. My old integrated sound had optical output, but it was not outputting in 5.1.

My games are outputting in true surround now, ie if someone is behind me i hear footsteps coming from only the rear speakers. The surround however is less clear with movies, exactly how noticeable should it be? Do to rear speakers often play something similar to the fronts only slightly muffled and quieter sounding?


Also, I looked into the trim level and I have a tone it sends through all speakers to adjust levels, I'll work on tweaking that. I currently have my rear speakers placed behind me and out slightly, I'm trying to set it up so I can use the setup comfortably for gaming as well as movie viewing, as I use my 24" lcd as a television in my bedroom.

Well I was under the impression that 5.1 channel audio cannot be sent over a toslink cable unless the sound card is able to process the 5.1 over digital with one of these real time encoding methods.No. Toslink (and digital coax) basically exist (as far as we are concerned) in order to transport multichannel (that would be DD and DTS 5.1) bitstreams from players to receivers as a digital bitstream for decoding by receivers. A digital connection (S/PDIF, which includes toslink and digital coax) carrying digitally encoded information is, basically, the only only way to transport the large amount of info contained in a DD/DTS5.1 soundtrack to a receiver. The digital info once converted to analog info can not be carried over an analog cable. It is just too much information, too fast, for the cable to carry. It is the ability to keep it compressed as digital info that enables even the digital connections to be utilized.


I was told that optical out only supports 2 channel PCM, except of course with sound cards with chips onboard like this one.Bitstream is compressed, undecoded digital info. PCM is decoded information, but still in a digital form. I think the reason optical can only carry 2-channel PCM is because once decoded to PCM it is much larger. Multichannel PCM would be too much info to be carried by an optical connection. Or it may be because of copyright concerns. No matter, though. It is irrelevant. Optical can only carry PCM as 2-channel. But as I was pointing out, we use optical connections to transport DD/DTS5.1 bitstreams (not PCM) to our receivers. The receiver then does the decoding. So all you want to do with your soundcard with DD/DTS5.1 material is send it as a native bitstream directly to the receiver for decoding. Do not decode it with your soundcard. Yes, I think your soundcard can decode DD/DTS5.1, but if you decode DD/DTS5.1 at your soundcard, as I pointed out, you would use its analog outputs to connect to either a 5.1 set of computer speakers, or to the multichannel analog inputs of a receiver (if it possesses them), although if you already have a DD/DTS5.1 receiver, there is no real reason to send the info to the receiver as analog info. Just send it via optical to the receiver for decoding.


My old integrated sound had optical output, but it was not outputting in 5.1.I don't know what it's exact capabilities were, but if it had optical, it could probably transport a digital bitstream through it to a receiver for decoding. If it was capable of sending DD/DTS5.1, it doesn't really "output 5.1" in the sense that it is already 5.1 sound. It outputs a digital bitstream which, if it is DD/DTS5.1, can be properly decoded, processed, and reproduced by a DD/DTS5.1 capable receiver into 5.1 output. But again, I do not know what its exact capabilities were. It may not have been able to send DD/DTS5.1 material via optical.


My games are outputting in true surround now, ie if someone is behind me i hear footsteps coming from only the rear speakers."True surround" means truly unique and discrete info in each channel and must be encoded as such with the proper equipment by the sound engineer who makes the soundtrack. As far as your soundcard and receiver is concerned, the only "true surround" formats are DD5.1 and DTS5.1 (there are some newer ones that you are not capable of). DD5.1 and DTS5.1 material is specifically encoded with 5 separate channels plus the LFE (subwoofer, .1) channel.

A game can only be output in "true surround" if it is encoded as such; i.e. DD/DTS5.1. I think that some games may be encoded as DD/DTS5.1 (the packaging will tell you), but most are not. They are usually DD2.0 or DPLII-encoded. The packaging will also tell you this. These are not true surround formats. They are encoded as 2-channel material. Your soundcard or receiver (both can do it, just in a little bit different ways) is able take this 2-channel material and create or synthesize (matrix) pseudo-surround sound from it. But it is not "true surround". It can sound very good and convincing, but it is still not "true surround" in the sense that DD5.1 and DTS5.1 are.

The best way to use the receiver to create pseudo-surround sound from 2-channel material (games, music CDs, DVDs that are not 5.1, etc.) is to send it natively from your soundcard (it will go as 2-channel PCM) to your receiver and let your receiver apply DPLII (Dolby Pro-Logic II). Most receivers have some other DSPs (digital signal processing) such as "Stadium", "Concert Hall, "Jazz Club", etc.. that can be used. Yours may even have a DSP called "Video Game". But most people still prefer DPLII. If the game is specifically DPLII-encoded, DPLII would be the DSP that you would want to apply. But you can experiment. What is important if you want to use the receiver for decoding and digital signal processing of 2-channel material is that you send the info natively to your receiver. Do not apply anything at all to it with your soundcard. Then you can see what your receiver is capable of.

If you want to use the soundcard to create pseudo-surround sound from 2-channel sources (games, music CDs, DVDs that are not 5.1, etc.) you can apply the two DSPs you mentioned; DD-Live or DTS-Connect. These DPSs will take the 2-channel source, create or synthesize (matrix) from it multichannel pseudo-surround that is then encoded and packaged to be sent as a multichannel digital DD5.1 or DTS5.1 bitstream to the receiver. But it is not true surround. It has been created by the soundcard in much the same way that a receiver does it with 2-channel material. The difference is that is is being packaged as DD/DTS5.1, even though it is not and never was "true surround". When you use these soundcard DSPs , make certain the receiver is setup to properly detect and decode multichannel DD or DTS material. It will decode the info and reproduce it exactly as the particular DSP created it. That is the only way you want to decode this stuff from your soundcard with your receiver. If you apply some sort of matrixing DSP with the receiver to this material atop what has already been done to it by your soundcard, you are going to create some weirdness. Most receivers can be configured to simply automatically detect DD/DTS5.1 bitstreams and properly decode and process them.

I would encourage you to experiment with applying DSPs to 2-channel material with EITHER your receiver or soundcard (with DD-Live or DTS-Connect). BUT NOT BOTH SIMULTANEOUSLY! One or the other. See what you like best with different 2-channel material.

As far as DVDs that are DD5.1/DTS5.1, you want to send these natively, as a bitstream, straight to your receiver for proper decoding. No reason to apply any sort of manipulation to it with your soundcard. In fact, you do NOT want to do that. You want it to arrive at your receiver as true DD/DTS5.1 bitstreams. Just send it as DD/DTS5.1 to the receiver which will decode it and you will hear it as "true surround", exactly as the recording engineer intended you to hear it. And again make certain your receiver is set up to simply decode DD5.1 or DTS5.1. As I said, most receivers will sense this automatically if properly configured to.



The surround however is less clear with movies, exactly how noticeable should it be? Do to rear speakers often play something similar to the fronts only slightly muffled and quieter sounding?You are probably having issues with DD/DTS5.1 movies because you are very unnecessarily applying either DD-Live or DTS-Connect to them pror to sending them to your receiver. So, you are taking something that is ALREADY properly encoded as true surround (DD5.1 or DTS5.1), unpackaging it, applying the DPS to it with your soundcard, then repackaging it and sending it to the receiver. You are most likely creating weirdness this way. You are applying a DSP atop something that is already encoded very specifically as discrete, multichannel info. You may very well be destroying the DD/DTS5.1 "true surround" sound in the process. Just send your 5.1 DVD's audio straight to your receiver as a DD/DTS5.1 digital bitstream and let the receiver do its magic. As I said, the receiver will properly decode and process the info exactly as the recording engineer intended.


Also, I looked into the trim level and I have a tone it sends through all speakers to adjust levels, I'll work on tweaking that.Yes, you can do this by ear. When sitting at your listening spot (the "sweet spot"), what you are trying to do is make certain this tone, as it comes from each speaker, sounds like it is at the same identical volume. This will assure that you hear the sound from each speaker at the volume it was intended to be heard and will allow you to adjust for any differences in volume that may occur, for example, because certain speakers may be further from you than others (or any other reasons).


You also want to set the speaker distances properly in the receiver. There is a place in the receiver for doing this. This will compensate for some speakers being further from your "sweet spot" and assure that the sounds arrive at your ears from the different speakers properly timed.

Getting these settings (and others) correct is called calibrating your system and once properly done will ensure proper reproduction of the sound.


I also think you should read your receiver's manual very carefully to make sure you are setting up all the other many (and there are MANY) settings properly.



Hope all that helps and does not confuse you further. I'm sure there are probably some typos or mistakes. Please feel free to ask more questions, but please read what I wrote very carefully to make certain you understand. ENJOY!

:)