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Post by Johnkenn on Mar 14, 2015 16:45:51 GMT -6
Here's my setup...I have the output of my Apollo (clocked by the Burl) going to the RM1794. Then analog out from the RM1794 to my ProAcs. In Sys Prefs, I select the Apollo as my output and input. Then of course, I select the Apollo in my DAW. Here's the question. When I listen to playback with that setup - it's really good - but not QUITE as good as when I select the USB connected RM1794 as my "soundcard" in Sysprefs. Seems like the top end is a little smoother and of course, it's taking the Apollo completely out of the equation. Is that the only way I'm going to be able to do that? What is the difference between the two that I might be hearing? Am I crazy?
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Post by wiz on Mar 14, 2015 17:00:03 GMT -6
Can you describe the analog and digital path? which of these units are connected via analog and which are digital?
cheers
Wiz
(ps yes.. you are crazy.. but we love you 8) )
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Post by Johnkenn on Mar 14, 2015 18:28:49 GMT -6
The Apollo is my main hub. I have the Burl connected for AD via Spdif (but use a word clock connection for clocking). The Apollo is connected via Spdif to the RM DAC. XLR cables from the analog outs of the RM DAC to the Power Amp (then the ProAcs)...
I also have the RM connected via USB. It will show up as an audio interface in System Prefs/Sounds. When I select it, the mac keyboard controls the sound - the Apollo and Console are skipped. There's a switch on the RM that signifies whether it's looking for the USB signal or a digital signal from another unit...You flip it to select. I feel like it sounds better like this. Not by a TON, but just a little better - little smoother on top. Just been meaning to ask for a while now.
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Post by stratboy on Mar 14, 2015 18:38:03 GMT -6
Maybe the way the data stream is handled from the computer to the RM via USB is better than the way it is handled from the computer to the Apollo to the RM? Maybe the RM DAC chip(s) do a better job converting a USB datastream than they do SPDIF? Maybe Ross's design needs an extra step going from SPDIF to the DAC chip input, or maybe the Apollo has some extra steps and you hear the difference in the top end?
Maybe I should stop speculating and ask svart to weigh in?
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Post by Johnkenn on Mar 14, 2015 18:48:29 GMT -6
Maybe my hearing is suspect... svart |
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Post by stratboy on Mar 14, 2015 19:17:34 GMT -6
Thanks, John. svart it is.
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Post by svart on Mar 14, 2015 19:21:06 GMT -6
Maybe the way the data stream is handled from the computer to the RM via USB is better than the way it is handled from the computer to the Apollo to the RM? Maybe the RM DAC chip(s) do a better job converting a USB datastream than they do SPDIF? Maybe Ross's design needs an extra step going from SPDFI to the DAC chip input, or maybe the Apollo has some extra steps and you hear the difference in the top end? Maybe I should stop speculating and ask Svart to weigh in? The DAC chips themselves take PCM audio streams. Either you have a SPDIF chip feeding this to them, or the Usb chip. I don't think there is an extra step, but it might be the usb chip generating a pcm clock. The RM might also have it's own internal clock for the usb setup but using extracted clocks from the spdif signal for spdif mode. This could give slightly better clocking for the usb mode. Then again, jitter purity isn't a guarantee of audio bliss. Sometimes if the jitter is mainly harmonic modulation, your audio might have some euphonic quality.. |
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Post by Johnkenn on Mar 14, 2015 20:38:12 GMT -6
I've ALWAYS wondered whether the DAC had it's own clock but was too embarrassed to ask...Honestly, this is what I thought - that the clock was different.
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Post by lolo on Mar 14, 2015 22:16:29 GMT -6
Yeah I think it might be bacause the RM has its own internal clock. Not sure. my RM clocks my rig via AES and its quita an improvement over the RME clock. I have his AD though. Internal clock is great
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Post by cowboycoalminer on Mar 14, 2015 23:05:13 GMT -6
Yeah there's an easier way. Hook the Ross Martin up by the SPIDF cable. Then you can use it standalone tethered to the Apollo. This is the way I have mine. Then in Audio/Midi setup on the Mac, select output channels 19 and 20 (which are Apollo's SPIDF outs. Boom, system sounds and all go through the RM and you can toggle back and forth in your daw without switching devises. See screenshot Attachment Deleted |
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Post by Johnkenn on Mar 15, 2015 8:51:10 GMT -6
Yeah there's an easier way. Hook the Ross Martin up by the SPIDF cable. Then you can use it standalone tethered to the Apollo. This is the way I have mine. Then in Audio/Midi setup on the Mac, select output channels 19 and 20 (which are Apollo's SPIDF outs. Boom, system sounds and all go through the RM and you can toggle back and forth in your daw without switching devises. See screenshot View AttachmentThat's exactly how I have it set up...I'm saying it sounds different in when running in USB mode than it does when it's using the Burl clock via spdif - and you can only do either-or |
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Deleted
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Post by Deleted on Mar 15, 2015 8:57:50 GMT -6
Personally, i have the impression, our Ross Martins sound slightly better clocked off the M-Audio lightbridge's SPDIF than thru it's own USB internal soundcard interface on universal USB audio drivers. Non-scientific claim. Very small difference to my ears.
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Post by cowboycoalminer on Mar 15, 2015 15:57:04 GMT -6
Yeah there's an easier way. Hook the Ross Martin up by the SPIDF cable. Then you can use it standalone tethered to the Apollo. This is the way I have mine. Then in Audio/Midi setup on the Mac, select output channels 19 and 20 (which are Apollo's SPIDF outs. Boom, system sounds and all go through the RM and you can toggle back and forth in your daw without switching devises. See screenshot That's exactly how I have it set up...I'm saying it sounds different in when running in USB mode than it does when it's using the Burl clock via spdif - and you can only do either-or Ahh. I misunderstood then. Everything I've tried sounds better to me clocked off the Burl. I'm convinced the Burl's clock is superior to many others which is probably one of the biggest reasons it sounds so good. To me anyway. The Symphony even sounds better clocked off the Burl. |
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Post by wiz on Mar 15, 2015 16:22:15 GMT -6
clocking is one of THOOOOOOOOOSE things... like .. err.. wives....
one mans atomic clock is another mans behringer.. 8)
The obvious thing I wanted to say, after checking you had it all cabled, sync'd and master slaved correctly... which you do.. is try the different things as clock master.. find one that you like.. and then.. well stick with it.
The difference you are hearing, do you think it would have an impact on how a mix would come out? (thats not a snarky comment, just trying to guage the difference)
cheers
Wiz
(sorry I didn't reply sooner.. I actually took the missus out for a Sunday drive.. and stayed completely out of the studio for a day... can't remember the last time I did that by choice... was the right thing
to do... I found this bakery that had THE best cream bun I have EVER had... oh man.... 8) )
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Post by Johnkenn on Mar 15, 2015 17:58:41 GMT -6
Oh no, it's very little difference. Enough to the point that I never bother switching to USB RM. But it does seem like the top end is a little smoother that way
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Post by lolo on Mar 15, 2015 19:55:41 GMT -6
Yeah I think it might be bacause the RM has its own internal clock. Not sure. my RM clocks my rig via AES and its quita an improvement over the RME clock. I have his AD though. Internal clock is great Just re-read this... Think quite an improvement is a little over the top :-) but I can hear a difference. Or maybe it a placebo effect :-) |
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Post by svart on Mar 15, 2015 20:55:15 GMT -6
SPDIF DACs usually don't have their own internal clock for the DAC chips themselves. They might have a PLL/DLL setup that locks to the extracted clock from the SPDIF signal and then clocks the DAC chips, but it's really dodgy and hard to get right external from the receiver chips.
SPDIF receiver chips like the DIR9001 that's used in the RM DACs doesn't need an oscillator for decoding operations, but you can use one if you want. I don't know if RM has used a crystal, an oscillator or left it free running on the decoded clock. In any case, the stream is linear and decoded in real-ish time compared to the recovered clock.
Since USB is a somewhat nonlinear data stream, you can buffer some of the data and then clock the USB receiver independently from other devices. This could cut down on jitter and other issues, but it's almost impossible to say what the difference is without significant testing.
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Post by mjheck on Mar 16, 2015 8:33:28 GMT -6
John, i have a similar setup using an Apollo - just with a 2192 instead of the Burl and a Zodiac Antelope instead of the Ross Martin.
My DA is also set up such that I can leave everything running through the Apollo as the interface, or connecting the DA directly to the computer via USB2.
I agree that there is a difference, no matter how small. I think the version routed through the Apollo actually sounds ever so slightly harmonically enhanced where the USB version sounds clear to the point of sterility. I assumed this had something to due with the attenuation stage of the Apollo, but I hadn't considered the clocking issue mentioned above.
I end up doing some IO routing, so I generally run it through the Apollo anyway. I think I have better luck doing corrective work like de-essing with the super clear version, but I will also freely admit the sample size is small and the confirmation bias potential is large.
MJH
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ericn
Temp
Balance Engineer
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Post by ericn on Mar 16, 2015 9:15:24 GMT -6
clocking is one of THOOOOOOOOOSE things... like .. err.. wives.... one mans atomic clock is another mans behringer.. 8) The obvious thing I wanted to say, after checking you had it all cabled, sync'd and master slaved correctly... which you do.. is try the different things as clock master.. find one that you like.. and then.. well stick with it. The difference you are hearing, do you think it would have an impact on how a mix would come out? (thats not a snarky comment, just trying to guage the difference) cheers Wiz (sorry I didn't reply sooner.. I actually took the missus out for a Sunday drive.. and stayed completely out of the studio for a day... can't remember the last time I did that by choice... was the right thing to do... I found this bakery that had THE best cream bun I have EVER had... oh man.... 8) ) As much as I have found the BLA clock to improve almost everytime , my faves are the Rosendahl for its analog sync capability and I can't remember who makes one but there is one that has a analyzer built in so you can see if it was worth all that money! Now I was told by the designers that they assumed a system as big as mine 4 Panasonic DA and 4 AD plus 2 Digi 192 digital would use a house sync / master clock but I have found decent short cabling and correct termination are far more important! |
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