S/PDIF Sync still not working...anyone?

Dpoirier said:
Ventanaman said:
FractalAudio said:
Doesn't your mixer have analog inputs? SPDIF sucks anyways. You get more noise and distortion due to clock jitter and cheap SRC chips than analog. Any Asian mixer is going to have the cheapest SRC chips that can be found and those typically have lousy distortion specs.
Click to expand...

I am happy to know this. I was feeling a bit inept at getting my SPDIF to sound better than my analog connection (I couldn't).
Click to expand...
I'm actually unhappy to hear this. I was (perhaps incorrectly) hoping that staying in the digital domain was a good thing (plus I was actually getting something out of the extra SPDIF input on my interface). Is this a common issue? How can one tell if a given audio interface uses good versus bad SRC chips?
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Hmm, I too had thought it would be better to use the superior a/d converters in the Axe and then stay in digital. Now I'm confused. :oops:
 
Sup?

Just for ref. Depending on what other gear I may be running at the time, I can run my Ultra into my my rig two ways via S/PDIF, the first is directly into the S/PDIF IN, on my RME HDSP 9652. which is my normal setup. I have not noticed any issue. The second is through the S/PDIF IN, on my Mackie D8B. I also have not noticed an issue with the axe-fx, but I have noticed some other gear in the past would come unlocked with the D8B on occasion, as the Mackie likes to be the Master and it also doesn't like to see any other clock source when it boots up, but every once in awhile it would have to be the opposite and I would get a piece of gear in and I would have to turn it on first . dont know if that helps at all with the Yamaha, but I just thought I'd throw that out there.

MOSHON
DAVE
 
Staying digital would be desired in a synchronous system. However, in the OP's configuration the system isn't synchronous. The mixer is running at one sample rate and the SPDIF in must be matched to that rate. Even if the rate is the same (i.e. the mixer is 48 kHz) it's not synchronous and therefore requires sample rate conversion (SRC). In this case the SRC would, for example, be 48.001 kHz to 47.999 kHz. The point being the clocks aren't locked.

Once you put an SRC chip into the equation you start getting all kinds of potential nasties. First of all you have jitter on the recovered clock which will degrade the SRC performance. Then you have the actual performance of the SRC itself. No consumer or pro-sumer mixing board is going to be using, say a Burr-Brown SRC chip. Most likely an AKM or even worse. Add to that that most Asian companies don't seem to understand proper grounding and shielding and use the cheapest PC boards they can get away with and you have a recipe for PLL clock jitter in the SPDIF receiver.

A good SRC chip costs more than a good A/D. So if you go analog into a digital mixer at least you don't have clock jitter problems since the A/D in the mixer is running off the mixer clock.

SPDIF is so bad that the (I forget the name of the consortium, AC '97 perhaps) ruled in favor of abandoning the standard for modern computers. Yeah, it's convenient but the clock jitter typically degrades the quality more than an equivalent analog connection. On my PC here I have a SoundBlaster X-Fi and (to me) the analog inputs sound much better than the SPDIF input. So I use the analog.
 
Is it your opinion then, that running analog to say, a digi002 is best practice (in terms of overall sound) - instead of using the SPIDF out from the Axe Fx (ultra in my case) into the SPIDF "in" on the 002?

I realize any of this can be subjective - but, your personal opinion please?



~
 
FractalAudio said:
Doesn't your mixer have analog inputs? SPDIF sucks anyways. You get more noise and distortion due to clock jitter and cheap SRC chips than analog. Any Asian mixer is going to have the cheapest SRC chips that can be found and those typically have lousy distortion specs.
Click to expand...

Cliff,

yes I have analog inputs on the mixer, but I have at least a few reasons for wanting to use the S/PDIF input.

1. I can save the mic preamps for..mics!

2. I've never had a problem using it before, it always worked fine.

3. as far as cheap SRCs go, it's hard for me to imagine that a mixer that is capable of 96 kHz/24 bit resolution is using cheap SRCs. that resolution is double the resolution of the Axe-fx, but I would never assume that the Axe-fx was using cheap SRCs. in fact, I think it was Frank Filipetti that won a Grammy for best engineered album (James Taylor's Hourglass) and I believe the whole album was recorded on the Yamaha 01V96. that bit of trivia may be useless to some, but I would think the quality of the mixer would have to at least be above average at that point.

4. both of my Ultras have a S/PDIF out, so I should be able to use them. I have a great deal of respect for the work you do and the products you've produced, so it's hard for me to imagine that you would have even bothered with S/PDIF I/O if it sucks so bad.

Cliff, I'm really just trying to understand why this is the digital product I own that doesn't sync with my mixer. I still love my Ultras, I think the Axe-fx is one of the greatest products for guitarists to come out in a long time and cannot see myself gigging with anything else. I would just like to see this work as well as everything else on the Axe-fx does!

some people from the 01V96 group suggested making a cable to go from my AES out to the S/PDIF in. a cable like this:

AES out: 2-------330 ohm-----+------------- SPDIF in
|
3--+ 91 ohm
| |
1--+------+---------+-------------
|
-
ground

any thoughts on this approach?

Thanks again for all that you do Cliff, it is definitely appreciated... (hope to see you at NAMM)

Steph
 
stefenator said:
4. both of my Ultras have a S/PDIF out, so I should be able to use them. I have a great deal of respect for the work you do and the products you've produced, so it's hard for me to imagine that you would have even bothered with S/PDIF I/O if it sucks so bad.
Click to expand...

I had the same thought.

Cliff, I'm really just trying to understand why this is the digital product I own that doesn't sync with my mixer. I still love my Ultras, I think the Axe-fx is one of the greatest products for guitarists to come out in a long time and cannot see myself gigging with anything else. I would just like to see this work as well as everything else on the Axe-fx does!

some people from the 01V96 group suggested making a cable to go from my AES out to the S/PDIF in. a cable like this:

AES out: 2-------330 ohm-----+------------- SPDIF in
|
3--+ 91 ohm
| |
1--+------+---------+-------------
|
-
ground

any thoughts on this approach?



Steph
Click to expand...

That's interesting. Is this simply an 'adaptor' to get from AES to S/PDIF, using proper termination and ground? Like I mentioned previously, I'm having problems with AES/EBU as well. Like you, when I use other devices (ie: Focusrite Liquid Channel) w/AES I don't have these problems.

Reading Cliff's thoughts on S/PDIF, really upsets my apple cart. We've all heard of jitter...but at least I assumed that the degradation was minimized if you used proper cabling. I've never seen it mentioned that Sample Rate Conversion took place when you 'locked' two digital devices. I've never heard of studio guys complaining about the quality of SRC chips....and they complain about EVERYTHING. I must have missed it somehow. Cliff obviously knows what he's talking about, and I choose to trust him more than my intuition here....but it's pretty heartbreaking. We've been told everywhere else, that a digital connection is superior to another conversion.

Anecdotal observation... When my interface (Roland VS-700R, not premium, but not cheap, at least by my wallet) freaked out repeatedly at a band practice/recording session...I swapped the AES connection to analog from the Axe-Fx. I noticed a marked improvement in the sound. Fatter, bigger, better. Not the improvement that audiophiles talk about when switching to mahogany knobs....it was the kind where even the drummer goes...'that's better'... :mrgreen:

Anyway, I'm very interested to see how this discussion resolves.
 
stefenator said:
Cliff,

yes I have analog inputs on the mixer, but I have at least a few reasons for wanting to use the S/PDIF input.

1. I can save the mic preamps for..mics!

Acknowleged.

2. I've never had a problem using it before, it always worked fine.


Irrelevant, and not the point I was trying to make.

3. as far as cheap SRCs go, it's hard for me to imagine that a mixer that is capable of 96 kHz/24 bit resolution is using cheap SRCs. that resolution is double the resolution of the Axe-fx, but I would never assume that the Axe-fx was using cheap SRCs. in fact, I think it was Frank Filipetti that won a Grammy for best engineered album (James Taylor's Hourglass) and I believe the whole album was recorded on the Yamaha 01V96. that bit of trivia may be useless to some, but I would think the quality of the mixer would have to at least be above average at that point.


Sample rate and bit depth have nothing to do with the quality of SRC conversion. Even the lousy chips will do 192 kHz at 24 bits. Furthermore, it says nothing about the quality of the clock recovery and attendant jitter. The reason SPDIF is a lousy format is because you have to recover the clock from the data stream. SPDIF uses Manchester encoding to "embed" the clock in the data. The amount of phase noise in the embedded clock is large due to a 180 degree binary distribution. The receiver PLL locks on to the clock but it's constantly getting yanked back and forth by the phase distribution. The PLL bandwidth has to be large enough to deal with the frequency stability but this is at odds with the desire for low clock jitter.

The Axe-Fx doesn't use any SRC. That's why the output is locked to 48 kHz.

4. both of my Ultras have a S/PDIF out, so I should be able to use them. I have a great deal of respect for the work you do and the products you've produced, so it's hard for me to imagine that you would have even bothered with S/PDIF I/O if it sucks so bad.


Yes you should and 99.9% of the users don't have a problem with SPDIF out. I don't know why your mixer is incompatible. The reason the Axe-Fx has a SPDIF out is that there are expected I/O for the device class. My DVD player has S-VHS and DVI outputs. The DVI output provides a better picture so I use that. The S-VHS outputs, however, are expected on a device of this type.

Cliff, I'm really just trying to understand why this is the digital product I own that doesn't sync with my mixer. I still love my Ultras, I think the Axe-fx is one of the greatest products for guitarists to come out in a long time and cannot see myself gigging with anything else. I would just like to see this work as well as everything else on the Axe-fx does!

some people from the 01V96 group suggested making a cable to go from my AES out to the S/PDIF in. a cable like this:

AES out: 2-------330 ohm-----+------------- SPDIF in
|
3--+ 91 ohm
| |
1--+------+---------+-------------
|
-
ground

any thoughts on this approach?

Try it. I doubt it will make any difference since it's just converting AES level to SPDIF level

Thanks again for all that you do Cliff, it is definitely appreciated... (hope to see you at NAMM)
I won't be there. Tom will be though.

Steph
Click to expand...
 
Tnx Cliff for sharing. Now I know that some issue I have had with digital out/in were not in my mind!
 
I've used SPDIF for at least 8 months now without an issue. However, I think I need to go back and try the Analog inputs into my audio interface to see if I notice any sound quality difference. This has been an informative thread.


Mark
 
FractalAudio said:
Even if the rate is the same (i.e. the mixer is 48 kHz) it's not synchronous and therefore requires sample rate conversion (SRC). In this case the SRC would, for example, be 48.001 kHz to 47.999 kHz. The point being the clocks aren't locked.
Click to expand...

Wow - thank you for that explanation. I'm using E-MUs 1820M SPDIF w/ my Ultra, telling the E-MU to get its clock externally (Ultra). Like other users I assume naively that it's best to stay in the "digital domain".

With my setup I sometimes hear really high-end cracklies/distortion that drives me nuts (just monitoring - nothing to do with recording/DAWs, etc.), as if two different sample rates are being used. Now I think I know what might be going on.

Thanks again.
 
Charlie Wardick said:
Here's my experience. Bought a Standard and hooked it up to my Delta-1010LT SPDIF. Synced the card to the Axe just like I did with multiple and far lesser gear than Axe-Fx. SPDIF status would go from locked to unlocked at random times. Did the usual troubleshooting 101 with cables, drivers, etc and went as far as trying it out all over again with another PC with know good SPDIF that had Delta-2496 and had the same issue. I could not resolve the problem.

I requested an RMA. Fractal tested and found no issues and could not duplicate my problem, but being the awesome company that they are they sent me back a different Standard. It worked fine on with both SPDIF connections that previously exhibited problems. Never had a problem since. So in my case it was an Axe-Fx hardware problem with the SPDIF sync drops. Since then I purchased an Ultra and have had no SPDIF issues.

That's my SPDIF story.
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Cliff,

in your last post you commented "I don't know why your mixer is incompatible."

I guess it's the combination of posts like Charlie's (I saw some others as well) coupled with my own experiences with my mixer and several different devices that are all able to sync with it, that caused me to start to wonder about which device has the issue. You're the expert, not me and the fact that you monitor this forum as well as provide answers and insight, is a great thing. Just wondering how to find out for sure which device has the issue.

I'll track down Tom at the show...

Thanks again!

Steph
 
I shoulda kept my mouth shut. :D My history is 1 out of 3 didn't work right with two different DAW rigs and different SPDIF interfaces. Your is 2 out of 2 bad with the same interface. There is a slight difference. That is why I asked earlier if you tried the Ultras on a totally different SPDIF device. My problem followed the Axe-FX regardless of interface (but then again it worked okay for Fractal), versus your problem moves with the interface (specific to your Axe and not your other devices). Must just be that clocking thing Cliff mentioned. Both your Ultras just don't agree with your interface. I hope you get it sorted.
 
Charlie Wardick said:
I shoulda kept my mouth shut. :D My history is 1 out of 3 didn't work right with two different DAW rigs and different SPDIF interfaces. Your is 2 out of 2 bad with the same interface. There is a slight difference. That is why I asked earlier if you tried the Ultras on a totally different SPDIF device. My problem followed the Axe-FX regardless of interface (but then again it worked okay for Fractal), versus your problem moves with the interface (specific to your Axe and not your other devices). Must just be that clocking thing Cliff mentioned. Both your Ultras just don't agree with your interface. I hope you get it sorted.
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Hey Charlie,

I wasn't trying to throw you under the bus (but since you posted a smiley face, I guess you know that)!

I'm just trying to get my head around the entire S/PDIF thing. if I get a chance to leave the booth at NAMM, I will try to track down some more info.

Thanks for the info Charlie, it is really appreciated!

Steph
 
tlainhart said:
FractalAudio said:
Even if the rate is the same (i.e. the mixer is 48 kHz) it's not synchronous and therefore requires sample rate conversion (SRC). In this case the SRC would, for example, be 48.001 kHz to 47.999 kHz. The point being the clocks aren't locked.
Click to expand...

Wow - thank you for that explanation. I'm using E-MUs 1820M SPDIF w/ my Ultra, telling the E-MU to get its clock externally (Ultra). Like other users I assume naively that it's best to stay in the "digital domain".

With my setup I sometimes hear really high-end cracklies/distortion that drives me nuts (just monitoring - nothing to do with recording/DAWs, etc.), as if two different sample rates are being used. Now I think I know what might be going on.

Thanks again.
Click to expand...

Funny you say that, I have sort of the same problem with my 1820 (without M). At one point I really have it in a recording, but most of the time it's only while monitoring. Mhm. Analog better than digital. Where's my record player?
 
sorry for not posting to this thread recently. I was tied up with NAMM and I'm just now getting back to normal (whatever "normal" means).

btw - bummed that I didn't get to see Tom. didn't know Fractal was not going to be on the floor, but Cliff's explanation makes sense (Fractal sells direct, not to dealers). however, would have been nice to have a room number or some way to come over and say hello. of course, I was stuck in my booth the whole time, so who knows if I would have made it anyway...

because I was stuck in my booth, I didn't have a chance to ask around, but I will send off some emails to a few contacts and see what happens. Anyway, I do have a few more questions if Cliff or anyone else is interested:

I understand that the Axe-fx doesn't use SRC and is "locked" at 48kHz, but if it's "locked" at 48 kHz, why does it occasionally lose sync with the device at the other end (even when the Axe-fx is the master)? like I said, I'm still trying to understand this issue, so forgive me for being such an idiot...

Cliff, I know that when you posted the "99.9%" that was more a figure of speech than an actual number, but it seems like, based on some of the posts to this thread that people have seen this as an issue, but ended up using a work around instead.

Just wondering if anyone has any other ideas/thoughts/tricks/suggestions on how to resolve this and get the S/PDIF working properly without resorting to a work around? I really enjoy the tone I get out of the Axe-fx, just wish the S/PDIF worked with my board (since everything else I've ever plugged into the board has worked, I guess I'm getting greedy expecting this device to work with it too...).

I still plan on gigging exclusively with the Axe-fx, it would be really nice if I didn't have to use a work around...

Thanks for listening!

Respectfully,

Steph
 
squealie said:
When I used my M-Audio Delta 1010 with Axe-Fx via S/PDIF, it would frequently show 'unlocked' in the status of the digital input / clock source. It would pick it back up after a second or two.

Now that I use a Sonar V-Studio I/O, when I try to use the AES/EBU ins for the AxeFX, it is an unreliable mess. Unusable.

Sounds like exactly the same problem you have... loss of sync. (clock)

I've been hoping to see someone mention this issue. A software fix would be ideal. Fingers crossed.
Click to expand...

For anyone following this...

I had given up on the AES/SPDIF outs of the Axe-Fx because of my issue above. This weekend, I was doing some bass tracking using a Focusrite Liquid Channel into my V-Studio, using the AES connection. I started getting the same 'freakouts' that I got when I used the Axe-Fx. I had used the Focusrite before, and never had a problem. LongStoryShort... I reckon I can discount the Axe-Fx as the culprit, and start to whine on the Sonar boards.

Actually, it happens reliably when I turn on the bathroom light. So it's probably some sort of surge/spike on the circuit. And I should either get better power conditioning, or pee outside. :ugeek:
 
squealie said:
squealie said:
When I used my M-Audio Delta 1010 with Axe-Fx via S/PDIF, it would frequently show 'unlocked' in the status of the digital input / clock source. It would pick it back up after a second or two.

Now that I use a Sonar V-Studio I/O, when I try to use the AES/EBU ins for the AxeFX, it is an unreliable mess. Unusable.

Sounds like exactly the same problem you have... loss of sync. (clock)

I've been hoping to see someone mention this issue. A software fix would be ideal. Fingers crossed.
Click to expand...

For anyone following this...

I had given up on the AES/SPDIF outs of the Axe-Fx because of my issue above. This weekend, I was doing some bass tracking using a Focusrite Liquid Channel into my V-Studio, using the AES connection. I started getting the same 'freakouts' that I got when I used the Axe-Fx. I had used the Focusrite before, and never had a problem. LongStoryShort... I reckon I can discount the Axe-Fx as the culprit, and start to whine on the Sonar boards.

Actually, it happens reliably when I turn on the bathroom light. So it's probably some sort of surge/spike on the circuit. And I should either get better power conditioning, or pee outside. :ugeek:
Click to expand...

I had to stop using the digital outs when connected to my DAW for the same reason. Whenever the heater or A/C came on the signal would lose sync. No noise on the analog side so all is good.
 
Just found this thread and it made me want to ask if I would be better off using analog going nto my Digi -002 rack?
 
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