Help: Understanding different inputs and Audio Formats/Quality

K

kellyk75

Audioholic Intern
I was hoping some of you guru's would be able to help me out. I am tryng to understand the best way to set up my home theater, but keep getting information that makes me think I can't do it to my standards without replacing my current hardware.

I currently own a crappy tv, a Yamaha RXV-657 receiver, Athena Point-5 Speakers, and a PS3.

I am planning to upgrade TV soon, speakers next (both for another thread).

My biggest question now lies with HDMI vs. Optical Inputs. I was told on purchasing the receiver that the only advantage (audio wise) to having HDMI over optical was 1 cable for both audio/video. I was talking to a friend who was telling me that when he hooked up his PS3 to his Yamaha (not sure what model, but it has HDMI inputs/output which mine does not), he could only have true 5.1 audio through the receiver if it was compressed. When it was uncompressed, it would come in as 2 channel and the receiver would decode and it sounded awefull. When he inputed through his HDMI in uncompressed format, everything worked and it sounded incredible. So much better in fact that he decided to sacrafice his 1080p for 1080i to route through his receiver in HDMI.

Could anyone help shed some light on the different compressions, sound quality differences, and medium for transfer (ie. HDMI, Optical, Digital Coax)? I did search, but got bombarded with info....... I am all confused. Please note that I understand the differences for video, it is the audio capabilities that I am unsure of.

Thanks in advance.
 
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nick1000000

Full Audioholic
I was talking to a friend who was telling me that when he hooked up his PS3 to his Yamaha (not sure what model, but it has HDMI inputs/output which mine does not), he could only have true 5.1 audio through the receiver if it was compressed. When it was uncompressed, it would come in as 2 channel and the receiver would decode and it sounded awefull. When he inputed through his HDMI in uncompressed format, everything worked and it sounded incredible. So much better in fact that he decided to sacrafice his 1080p for 1080i to route through his receiver in HDMI.
I can start this off by saying that the reason the sound was so bad in the uncompressed audio compared to the HDMI uncompressed audio is the bandwidth. When the audio is uncompressed the bandwidth exceeds the capabilities of optical and coax wires. HDMI and analog on the other hand can handle those bandwidths.
 
Gaigebacca

Gaigebacca

Audioholic
I too own a PS3 and was before using an optical connection to connect to an old crappy Sony HTIB setup. Yes the optical is very limited in the bandwidth it can push over, and is limited to stereo PCM tracks. The sound quality even from that if your receiver can push that through using Pro Logic is still better than regular DD 5.1... I recently upgraded to an Onkyo SR-TX605 in order to get the HDMI audio, and the clarity you get from the HD audio is above and beyond even DTS tracks on regular DVD's.

HDMI 1.3 allows for 8 channels of uncompressed audio, so basically 7.1. HDMI is also the only way you are going to get Dolby TrueHD and DTS HD Master tracks to your receiver. Now the PS3 can either decode these itself, via Linear PCM or send the info via Bitstream to an appropriate receiver.

Since there is no way to output Coax out of the PS3, the only way to get full channel surround sound of HD or uncompressed audio is through the HDMI cable.

Now if you use the optical cable currently, most of the HD audio tracks will down convert the signal to the maximum bandwidth that cable can provie, you are cutting many corners (going from like 3-4 mps down to like 640 kbps or 1.5 mps I believe) but the audio itself is still a little cleaner than regular compressed tracks. This is especially true with the DTS HD tracks, with will still make use of the "core" of the track if you don't have HDMI.

Your friend made the right decision to drop from 1080p to 1080i in order to get the HD audio, there really is that big a different in that it more than makes up for just having a interlaced screen rather than progressive.
 
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