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Spdif
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| echosystm |
I'm trying to hook my two computers together via spdif. It is working, but if I use an rate other than 48000hz I get nothing but horrible crunching and static noises. I need to run at 44100hz as this is what I do all my projects in.
I've heard spdif just wont run at anything other than 48000. Is this true? I'm connecting an M-Audio Audiophile 24/96 to an Echo AudioFire 4. |
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| DJ RANN |
Technically S/PDIF should support both 44.1 and 48k (it can for specific formats support 32k too). It should be changeable from within the delta control panel. You must not have any audio applications open/running in the background to be able to change it.
I know its a dumb question but you are using a proper 75ohm S/PDIF cable right? (and not a standard phono lead?) |
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| 3F05Q |
| Another dumb question: Did you set BOTH machines to 44.1? |
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| antronx |
The cable does not have to be 75 ohm if the run is short. Any normal shielded coax type RCA cable would work. In fact, you would never get consistent resistance, because RCA connectors are not 75 ohm.
Did you make sure your clock source is set properly? One interface should be the source and another should be set to receive that clock. I have M-Audio Fast Track 4x4 and the driver it comes with, does NOT let me set clock source, sample rate and bit depth. It all magically just appears by itself... I had it once connected to Digi 002 rack via spdif in and out, and it did sound garbled and clicky. I was sending audio from M-Audio to Digi. I went into Digi's config page, and changed clock source from Internal to Spdif and it worked fine since. Actually, it sounds little better than running analog between the two. I now want to completely eliminate any analog paths in my setup, except path from Digi to the monitors. |
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| DJ RANN |
Incorrect I'm afraid antronx.
How many "shielded" RCA cables have you come across? RCA = two conductors....think about it.... RCA = unbalanced.
And yes I used to work for a AV cable manufacturing company and we did very rarely do a custom (handmade) order for RCA's on balanced (shielded) cable, where the shield was bridged to stop interference on 15m + runs. But this is the the exception.
You can get away with a short RCA sometimes but because of the way s/pdif signals work, the sample rate is set by a data message which just so happens to be usually the first thing to be affected by degredation of conductivity or interference.
You can also get 75ohm RCA's but it is not normally necessary as this is usually the shortest part of the conductive path. |
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| antronx |
Since you are from England, could it be that term "shielded" means something else over in your country?
By shielded i meant that it has the wire screen or mesh("-", ground) wrapped around the center conductor("+").
Balanced cable has two identical wires, hot(+) and cold(-) twisted together, and a shield (ground) wrapped arpund them. Signal in cold(-) wire is a replica of signal in hot(+) wire, but with it's phase inverted. |
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| DJ RANN |
You're absolutly right - "shielded" is generally a term applied to balanced cables over here.
I lived for a period in the states/canada and it was like learning my whole terminology over again, not to mention polarity of wiring!:D |
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| antronx |
| Yea, if everyone on Earth could speak same language, it would be a lot more peaceful. I guess the difference in terminology could have caused many misunderstandings and debates on the internet. Its funny how we forget that on the internet, we are not in our own country anymore. That's why i love it. Most of my terminology i have learned from talking to engineers and sound guys over here in US. |
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| CReddick |
I think it's funny they call that audio interface the 'Audiophile' and it doesn't even have BNC word clock connections.
This definitely sounds like a digital sync issue. Be sure your source clock is set to internal, and be sure to set the receiving audio system to sync off the incoming word clock. |
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| DJ RANN |
+1 antronx, so true.
creddick - s/pdif doesn't use word clock. It contains sync as part of the data stream of the overall signal. but that's a good idea to check that the clock is set right. |
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| CReddick |
word clock = the sync you're referring to.
It can be carried over the signal path, or separately over a BNC like I mentioned above.
Regardless... you're correct. the sync source / slave needs to be set appropriately for this to function. |
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