Why is my SP/DIF input quiet in Logic Pro?

Question

Why is my SP/DIF input quiet in Logic Pro?

Can anyone please suggest why my drums, inputted via SP/DIF are really quiet in Logic Pro 9.1.3?

The strange thing is that their volume looks healthy in and out of my Fireface 800 software mixer panel (Fireface 2.62, Fireface Mixer E2A) it's dancing about in the middle of the meter strip - but the signal arriving in Logic from there is really quiet, down in the bottom 5-8% of the strip with the slider set at 0DB.

If I apply a 12DB Gain insert in Logic, the level in the Fireface mixer out is on the border of clipping and yet the drum track is still way too low in the mix.

All other levels in and out are fine, from analogue and software instruments. I'm using a Logic Pro 9.1.3, Fireface 800, Mac Pro 2 x 3.2 GHz Quad-Core Intel Xeon, 8GB RAM, OS X 10.6.6, Roland TDW20 Expanded V-Drums. The drum signal is synced at 44.1Khz and that's the only signal path from them to Fireface and Logic.

Any suggestions greatly appreciated!

Mac Pro, Mac OS X (10.6.6), Logic Pro 9.1.3, Fireface 800

Posted on Apr 6, 2012 12:36 PM

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Answer 1

Pancenter

Level 6

14,788 points

Apr 6, 2012 1:46 PM in response to Phil the Muso

Explain your setup, V-Drum has a s/pdif output that's going into the Fireface 800?

Signal looks good in the FireWire software mixer but signal is low in Logic?

If this is correct, you should only be using a single s/pdif cable, out from the V-drum to the Fireface 800 s/pdif IN.... the V-Drum should be the master digital clock with the Fireface set as slave to the V-drum clock over the s/pdif signal.

Theoretically.. a digital S/PDIF, ADAT, Optical, AES/EBU signal should NOT have a gain stage anywhere in it's path or it loses perfect bit replication.

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Answer 2

Apr 6, 2012 6:49 PM in response to Pancenter

Thanks Pancenter. Yes, the V-Drum has one s/pdif single cable going into the Fireface 800. The signal looks good in the Fireface software mixer but is low in Logic. The V-Drum is the master clock ... actually I can't see where that's set in the V-Drum interface, but the Fireface is saying that it's synced at 44.1kHz and that it is in slave mode.

Yes it seems odd that gain is possible if this is a digital signal. There is no other output other than the s/pdif connected to the Fireface though.

Maybe I should update the driver for the Fireface if there is a later one ... just worried if it may screw something else up...

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Answer 3

Pancenter

Level 6

14,788 points

Apr 7, 2012 12:29 AM in response to Phil the Muso

You could create an "Input Object" in the Environment and set it to the s/pdif stereo input, you could then add gain there and it would be recorded.

What is the Master Level of the Fireface software mixer set at?

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Answer 4

Apr 7, 2012 5:01 AM in response to Pancenter

Whoops sorry I seem to have marked this as solved accidentally. Thanks. Yes, I've tried that and the result is a louder recording but I still can't get the gain high enough to compete with other tracks that way.

The Fireface software mixer doesn't have master outs. The FF input and 'playback' sliders for the s/pdif channels don't affect the displayed signal level (good) but the FF 'output' sliders do change the displayed signal level - although they don't change the level in Logic.

I have set my Logic input to be audio. I haven't told Logic that the signal is s/pdif ... since I assume that's just an issue for FF. Perhaps this is more likely to be a FF signal routing and levels issue? May I need to find and read a manual for FF.

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Answer 5

Pancenter

Level 6

14,788 points

Apr 7, 2012 10:01 AM in response to Phil the Muso

Looks like your level sliders are at +6 in the Fireface mixer, if you set them to unity gain (0.0) I bet they will reflect close to, if not exactly what the Logic mixer is showing, or do they affect the output level?

How about the Roland's master output, does it affect s/pdif volume?

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Answer 6

Apr 7, 2012 2:56 PM in response to Pancenter

Thanks. Those sliders don't affect the level. The Roland's master output was set just below maximum. I've set it to maximum now but there's no discernable difference.

One strange thing is that when the Roland drums are powered up, if midi is connected, the volume slider on my Logic channel for the drums drops by 2db and the channels are panned by -13. But 2db isn't much of a difference though. Removing midi leads still leaves me with the massive volume drop between the Fireface I/O and Logic.

My s/pdif connection between the Roland and Fireface isn't long enough so it's bridged via a connector, but since the Mac says they're synced at 44.1 I suppose that's not the issue, and hey the signal looks good in the Fireface.

What a mystery ...

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Answer 7

Pancenter

Level 6

14,788 points

Apr 7, 2012 11:55 PM in response to Phil the Muso

Do you have other type of settings that control signal strength, (Consumer -10db, Professional +4db) on the Fireface hardware and or software mixer?

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Answer 8

Apr 8, 2012 6:32 AM in response to Pancenter

Thanks, it's so kind of you to help. Yes, set to + 4db. I'm going to try updating all the software the Fireface driver and software, and going from OS X 10.6 to 10.8, then Logic.

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Answer 9

Pancenter

Level 6

14,788 points

Apr 8, 2012 8:29 AM in response to Phil the Muso

Before doing any upgrading I'd be trying different options on the RME panel.

Output of the Roland is likely to be at consumer level.

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Answer 10

Apr 8, 2012 1:33 PM in response to Phil the Muso

Hi,

It's a long shot, but i noticed that you output your stereo drum track to Out-11-12. Depending on your routing in the RME Total mix mixer, you might have phase issues. What happens if you select your Main Out (1-2 ) as the output of the track?

I find it weird also that you have such a low input in the RME mixer. I don't have a Roland V-Drum but a lot of those hardware "synths" with S/PDif don't control the digital out with the hardware volume pot on the unit. They just send to max volume through the digital out. So, maybe you have a setting in the V-Drum menu to choose an output level for the S/PDif?

And one last thing, your RME mixer looks pretty old? I have a BabyFace and the GUI on the TotalMix doesn't look like that at all. Maybe an update of your RME software would be a good idea...

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Answer 11

Apr 8, 2012 3:55 PM in response to Pancenter

Thanks to both of you. Yes, I tried all the options on the RME panel. Whilst increasing the level out to High Gain raised the drums volume, it also raised all the other tracks' volumes too. I didn't actually fiddle with the level meters settings since I assumed it wouldn't affect the actual signal levels though.

Good point about Out to 11-12. That was just an experiment. It's been 1-2 rest of the time.

I've not found any s/pdif output controls in the Roland V-drum documentation, menus, or online. Someone posted that it's automatically enabled when main outputs are enabled. I guess they're just on or off. The signal looks okay to me in the Fireface, it's just massively lower in Logic.

Well the RME mixer looks a lot prettier now I've updated the software. I also updated to Mac OS X 10.6.8 and to Logic 9.1.7 without any problems.

I returned Logic to default settings too, and still no luck with the low s/pdif signal level. I wonder if it's an issue that the V-drums are 16 bit? They're reported as synced okay though.

Aha! Just spotted my old minidisc player. It would be interesting to see what that makes of the volume levels from the drums s/pdif and the Fireface s/pdif out.

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Answer 12

Apr 9, 2012 3:13 AM in response to Phil the Muso

Have you checked the Audio Midi set up on your Mac? I spent a few frustrated hours wondering why i could get no ADAT action out of my 828MK3 only to find that the audio mixer in AUDIO MIDI set up had all those input channels turned down. Note that the mixer for all input audio channels do not appear unless the audio interface is turned on.

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Answer 13

Apr 10, 2012 5:13 AM in response to Amanita_X

Thanks Amanita, yes I have checked that. In fact the mixer channels seem to have a reasonable signal level, peaking about half way up the range - well I'd expect a little more output from a drum kit being hit hard, but it's at a practical level in the mixer. It's when that s/pdif signal gets into Logic that it drops massively. Analogue signals are fine, it's just the s/pdif signal that's getting mistreated.

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Answer 14

Apr 10, 2012 7:06 PM in response to Phil the Muso

Stupid question, but you got yourself a proper S/PDif cable, not just a standard RCA cable? I find your levels pretty low on your first screenshot of the RME mixer. If you bring your faders on the RME channels to 0dB, does the meters are at the same level as the level meters on Logic's mixer? Boosting the faders on the RME mixer as no bearing on the levels that are fed to Logic since it's a digital input and the signal is not going thru a preamp...

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Answer 15

Apr 16, 2012 4:05 AM in response to I want My ES2

Thanks a lot. You've probably pinpointed the problem there ... I'm using standard RCA cable, in fact with a connector in the middle too since it's not long enough. I thought that since it's a digital signal, it would be either on or off, but I've now read that standard cables cause jitter and errors.

The faders on the RME don't change the level.

I've ordered a 3 metre gold-plated S/PDIF cable now and hopefully that will solve it.

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