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Does this mean it is bitperfect?

post #1 of 46
Thread Starter 
I have a Chaintech AV-710 connected to a receiver via optical out.
When I play a movie with DTS audio the "DTS" light on the receiver lit up and I there are sounds coming from the 5 speakers. Does that mean the AV-710 is outputing a bitperfect signal?
post #2 of 46
Yes, but for movie sound tracks this works for almost all cards on the market. To test for bitperfect playback of CD material download one of the test tracks from www.sr.se and play those.

http://www.sr.se/laddahem/MultiKanal...EST_011212.zip

These are 2 channel 16/44.1 stereo WAV files where the content is actually an encoded 5.1 signal. When this signal hits your receiver unmodified the receiver will detect it as a surround sound track. If your sound card is not bit perfect for 16/44.1 stereo material it will only play hiss.

Cheers

Thomas
post #3 of 46
This test will work with any DTS cd right?
post #4 of 46
Thread Starter 
thomaspf, thanks for you pointing me to the surround-test file.
Looks like my card is not bitperfect. The receiver shows "DTS" but all I hear is silence with an occational pop/click.

I'm thinking about upgrading to the E-Mu 4040. Is that card bitperfect (without flashing the bios like the AV-710)?

By the way, how do I flash my AV-710? I can't seem to find a guide and I'm afraid I might destroy my soundcard.
post #5 of 46
If I play that file in WMP or foobar2000, it produces a hiss too. Does that mean my harddrive is not bitperfect? Or that windows is not bitperfect? Or is it just interpreting the data as 44.1/16 2ch PCM (which is indeed what foobar says)?

I think the testing methodology is seriously flawed. You are expecting a receiver to handle something it shouldn't necessarily handle.
post #6 of 46
For bit perfect output on the AV-710:
1. Switch the digital out to "PCM only".
2. Enable automatic sample rate.
3. Turn up Wave playback volume slider to max.
post #7 of 46
Quote:
Originally Posted by Klefbek
I think the testing methodology is seriously flawed. You are expecting a receiver to handle something it shouldn't necessarily handle.
Actually surround sound receivers expect to handle DTS streams and do that quite well. What seems flawed in your case is the playback of the WAV file to the digital output of your sound card. The problem is not with WMP of foobar but with the handling of the sound data by the WAV and directsound apis before this data is even handed to your sound card.

And yes you can also try this with any of the commercially released DTS CDs.

Cheers

Thomas
post #8 of 46
If you are just trying to play a DTS cd or DTS encoded .wav file on your computer, VLC Player plays them without any extra codecs required. I didn't find that to work with foobar2000; I had to change the file extension from wav to dts, and I had to download the DTS decoder component.
post #9 of 46
The test is not flawed ,in fact it is the only way to test for bitperfect playback, well you can do the HDCD test but few people have HDCD receivers.

It is very doubtful that you have bitperfect playback with the AV710, probably the biggest myth on this site is the bitperfect AV-710. Unless you are prepared to boot to DOS don't expect bitperfect with the AV710, spend the extra $60 and get an EMU 0404.
post #10 of 46
dude, regal, if it is such a big myth, then why do so many people have bit perfect audio playing out of their AV-710. in the thread YOU STARTED there were quite a few people that definitely had bit perfect playing...
post #11 of 46
Quote:
Originally Posted by werdwerdus
If you are just trying to play a DTS cd or DTS encoded .wav file on your computer, VLC Player plays them without any extra codecs required. I didn't find that to work with foobar2000; I had to change the file extension from wav to dts, and I had to download the DTS decoder component.
Well, in that case you do the decoding on the PC and then send a standard PCM signal to the card. The result will of course play but you still don't get the bits you are playing out of the sound card.

I thought the idea of this thread was to get bitperfect playback not the question on how to play DTS CDs if you are lacking it :-). Nice solution though.

Cheers

Thomas
post #12 of 46
Quote:
Originally Posted by lmf22
thomaspf, thanks for you pointing me to the surround-test file.
Looks like my card is not bitperfect. The receiver shows "DTS" but all I hear is silence with an occational pop/click.

I'm thinking about upgrading to the E-Mu 4040. Is that card bitperfect (without flashing the bios like the AV-710)?

By the way, how do I flash my AV-710? I can't seem to find a guide and I'm afraid I might destroy my soundcard.
Mine plays the test perfectly after flashing. it was super easy. I found the files here: http://www5.head-fi.org/forums/showthread.php?t=132155

I used an .iso file of a DOS flash CD, open it in UltraISO put the 2 files in there (eeprom.ini and eepwra.exe), burn and boot from the CD and type eepwra <enter> reboot - done. Install Prodigy 7.1 drivers. Trying to locate the DOS flash CD .iso image on bootdisk.com with no luck so far. I've had this for years. can send if needed - 2mb.

The flash cd is on www.bootdisk.com under: Need To Flash Your BIOS On A PC With No 1.44
post #13 of 46
Quote:
Actually surround sound receivers expect to handle DTS streams and do that quite well. What seems flawed in your case is the playback of the WAV file to the digital output of your sound card. The problem is not with WMP of foobar but with the handling of the sound data by the WAV and directsound apis before this data is even handed to your sound card.
Uhh, you don't adress my point. I never said receivers don't handle DTS. My point was that a receiver doesn't necessarily handle broken streams.

If you put a 44.1/16 2 ch WAV header in front of it, what else do you expect a receiver to do than to interpret the stream as 44.1/16 2ch PCM? WMP says that's what it is, and foobar says that's what it is. There is a WAV header that says that it is.

Since any random sequence of bytes is a valid PCM stream, nothing will ever make a problem about it not being a valid PCM stream, or try to figure out if it is a DTS stream or not, unless you make special provisions for that. But since you put a WAV header in front of it (which even has false information about the stream), you could even say it is not a valid DTS stream anymore.

The file works fine if I remove the garbage.
post #14 of 46
Quote:
Originally Posted by Klefbek
Uhh, you don't adress my point. I never said receivers don't handle DTS. My point was that a receiver doesn't necessarily handle broken streams.

If you put a 44.1/16 2 ch WAV header in front of it, what else do you expect a receiver to do than to interpret the stream as 44.1/16 2ch PCM? WMP says that's what it is, and foobar says that's what it is. There is a WAV header that says that it is.

Since any random sequence of bytes is a valid PCM stream, nothing will ever make a problem about it not being a valid PCM stream, or try to figure out if it is a DTS stream or not, unless you make special provisions for that. But since you put a WAV header in front of it (which even has false information about the stream), you could even say it is not a valid DTS stream anymore.

The file works fine if I remove the garbage.
Or you could just buy a DTS audio CD.
post #15 of 46
Quote:
Originally Posted by Klefbek
If you put a 44.1/16 2 ch WAV header in front of it, what else do you expect a receiver to do than to interpret the stream as 44.1/16 2ch PCM? WMP says that's what it is, and foobar says that's what it is. There is a WAV header that says that it is.
Wave headers and other such things aren't transmitted over S/PDIF. All it does is set a clock rate and transmit PCM audio. That's it. However DTS capable decoders recognise DTS compression and will engage their decompression engine to play the sound back.

You can verify this with a DTS receiver and a CD player. Playing a DTS CD in it will result in noise on the analogue outs, but the receiver will notice this is not random noise but rather a DTS bitstream and will decode it. I've burned a number of DTS CDs and they all work just fine. The DTS encoder just makes wave files that you burn with any burning software.

Thus, you can test a computer in the same way. If the output it bit perfect, it will work fine. If the computer or soundcard is modifying the signal, it will fail. It's not like the computer adds non-standard information to the S/PDIF stream or anything.
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