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Post by Martin John Butler on Feb 2, 2018 8:56:50 GMT -6
Bradd, when you said, "I send each track of Logic out D/A to individual channels on the Ghost", I'm curious, exactly how do you do this, what kind of cable goes from computer to your board?
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Post by bradd on Feb 2, 2018 9:07:33 GMT -6
Martin, I have DSUB to 1/4 inch snakes that go out from my Symphony to the inputs on my Ghost.
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Post by kcatthedog on Feb 4, 2018 2:36:15 GMT -6
Tomorrow, I’ll copy a little table about signal level checks. From reading the thread I now understand if using inserts that drops -2db and the line input starts attenuated -10db so a returning direct out signal would be down -12 dB by default.
The delta gain can be used to mitigate and raise signal + 12 dB for unity.
So, I have been checking and measuring this using 1k sine wav, then also checking my master out led levels and have patched those back into my daw.
Basically I have 2 channels 5/6 panned L/R with the sine plug inserted and 2 more channels also panned receiving master out input 15/16.
I am also comparing signal levels on my symphony mkii touchscreen and it’s software GUI ( apogee controller) and found a discrepancy. The summed signals are different levels L>R by about 5 dB.
All preceding levels are essentially matched, using all new gear (except delta) and all cables are also new and balanced.
If I switch the line input cables 6/5 to 5/6 on delta inserts the apogee GUI levels switch to L<R by the same roughly 5 dB amount.
I took screenshots and pics of delta metres, thought I ‘d recheck tomorrow?
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Post by stormymondays on Feb 4, 2018 3:55:02 GMT -6
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Post by kcatthedog on Feb 4, 2018 4:56:36 GMT -6
What do you think ,as here is what I see: screenshot: 5 Logic Sine plug settings = same -12 5(2) Logic channel levels = same -12 ( delta 5/6 gain adjusted, Delta Master l/r returned to logic 15/16, yes at 0 dbf on Delta master led ( see pic) 6(2) Apogee Control Mix = same channel levels but Master L>R ? 7(2) Apogee Control i/o = " ", see levels analog +4 dbf, digital -16 dbf (all channels ) I understand this system is still new to me and I am still running it in (testing) but am I missing something obvious ? Possibilities: Apogee Control GUI is wrong Cables ( although new, maybe one is lowering the signal) Patchbay ( Samsung S although new, maybe one is lowering the signal) Attachment Deleted
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Post by matt@IAA on Feb 4, 2018 9:28:20 GMT -6
Tomorrow, I’ll copy a little table about signal level checks. From reading the thread I now understand if using inserts that drops -2db and the line input starts attenuated -10db so a returning direct out signal would be down -12 dB by default. The delta gain can be used to mitigate and raise signal + 12 dB for unity. So, I have been checking and measuring this using 1k sine wav, then also checking my master out led levels and have patched those back into my daw. Basically I have 2 channels 5/6 panned L/R with the sine plug inserted and 2 more channels also panned receiving master out input 15/16. I am also comparing signal levels on my symphony mkii touchscreen and it’s software GUI ( apogee controller) and found a discrepancy. The summed signals are different levels L>R by about 5 dB. All preceding levels are essentially matched, using all new gear (except delta) and all cables are also new and balanced. If I switch the line input cables 6/5 to 5/6 on delta inserts the apogee GUI levels switch to L<R by the same roughly 5 dB amount. I took screenshots and pics of delta metres, thought I ‘d recheck tomorrow? Not sure your first paragraph is right. The gain structure in the console may be such that if you supply a signal that is +4 dBu at the direct out, the patch point is -2 dB unbalanced. This is pretty common but it doesn’t mean you lose 2 dB by using an insert. The input having -10 dB gain may mean there is a minimum gain in the input stage so the signal is padded down going in in order that a +4 signal applied results in a unity gain structure through the whole thing. But the minimum gain may be 8 dB so the pad may be 18 dB or something. Again, this is all internal and works itself out without you seeing a loss. The console doesn’t know what you’re sending it. It just “sees” a voltage and that voltage is gained by the amplification stages. You could get a multimeter and measure the actual voltage being sent at 0 VU from your converters and likewise from your console.
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Post by kcatthedog on Feb 4, 2018 10:46:21 GMT -6
Ok, but if it all sorts itself out, remember that my signal came back from the delta -15 dB or so from what I sent?
That was the original thing, I was trying to understand?
To do the measurements you describe I would measure the voltage of my male trs coming from the apogee and the master out from the console ?
As wiz pointed out I can mitigate this drop with the delta channel gain, but I was curious about the last level discrepancy in the apogee control GUI, but I will contact its CS and see what they think too.
All that being said, I am really enjoying the experience of mixing in the delta , using the eq’s and patching to my OB comps!
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Post by matt@IAA on Feb 4, 2018 19:25:48 GMT -6
I mean it sorts itself out in the sense that if you put a +4 dBu signal in, a -2 dB patch point will be -2 dB at unity gain. And if you put a +2 dBu signal in the patch point will be -4 dB, etc. So you could also think of a -2 patch point as a patch point 6 dB below the input at unity gain.
+4 dBu corresponds to 1.228 V. When people are saying maybe you have the converter set for -10 dBV instead of +4 dBu that means the nominal output voltage will be .316 V, or -7.78 dBu. Combine that with a -2 patch point and you are at -13 dBu if your console is set for 0 VU = +4 dB and unity gain.
Digital is another scale entirely. dBFS, or full scale. So -18 dBFS just means 18 dB of headroom before converter clipping - it doesn’t have any concrete voltage relationship.
So the important thing is to pick a 0 VU signal level, make sure all of the voltages jive, and make sure all devices are set to that 0 VU. 18 dBFS = + 4 dBu = 1.23V = 0 VU is common.
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Post by kcatthedog on Feb 4, 2018 20:51:34 GMT -6
Thank you.
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ericn
Temp
Balance Engineer
Posts: 15,011
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Post by ericn on Feb 5, 2018 9:27:05 GMT -6
Understanding gain structure and how to use a tone generator and meters is great and will help you in the long run, but remember in the real world we deal with dynamic signals. That means the trick in all this is you figureinng out how this all applies to you rig with a mix flowing through it and what is optimal for you and that half of what we do is push it harder for tone !
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Post by kcatthedog on Feb 5, 2018 11:01:41 GMT -6
Thx Eric, Agreed: ! Wiz already gave me the real world unity fix, but as I am still getting to know and test my new system I was doing the level testing just to see ? I hsve never had a real 16-24 input/channel system with 3 48 point patchbays and 20 odd channels of OB to get my head around! But I really believe in the learn by doing idea, so dive right in and diagnose problems as I bump into them !
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Post by matt@IAA on Feb 5, 2018 11:18:58 GMT -6
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Post by kcatthedog on Feb 5, 2018 18:13:37 GMT -6
Talk to Apogee CS about the master balance discrepancy and with the two channels panned hard left/right getting sine waves of the same amplitude they said that doesn't make sense, nor had they seen that before (at least I'm original) ! They asked to check if I had any other inputs causing this but I didn't So we did a hard reset of the symphony mkii from touchscreen setting's screen and power down up cycle, then session was perfect.
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Post by matt@IAA on Feb 8, 2018 8:52:55 GMT -6
Session was perfect meaning that your levels are now 0 in 0 out with the console set to unity gain?
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Post by kcatthedog on Feb 8, 2018 9:11:11 GMT -6
Essentially yes.
But, I contacted Apogee CS to understand why the l/r balance was different with the same level signals passing ?
I noticed after I stopped talking to CS that I could trigger this difference and I realized that it operator error ? In my sine wave test I was sending th
I was sending the same sine wave through 2 channels panned L/R but when I was bring that back into the board and to logic from the master outs I had not panned (duh!) so the signal were coming back centered, when panned levels l/r were balanced.
Now, I am working in one session and I have made 2 arrangements in logic :
- Option one is the send/receive at unity gain to the delta eq/OB comp to logic mix, and - Option two is mixing in the delta and printing that stereo master out.
My faderport 16 is supposed to show up tomorrow so I am interested, so I am interested to see how in option 1 above I would then finesse the mix in Logic using automation etc., or I could manipulate with automation the mix that is begin sent in Option 2 and again seeing which workflow I prefer and why ?
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Post by kcatthedog on Feb 8, 2018 12:22:27 GMT -6
So, a question about mixing technique, not system set up.
I am more a fan of eq first, then comp but I have never had 16 channels of 4 band eq and roughly 12 channels of different OB comps to mix with before
I want to have fun learning how to use this well and on the one hand, also believe in, if it sounds right, it is right, but any advice about approach and learning how to better hear the differences in my various compressors etc. ?
I think the first big lesson learned using the delta EQ, balance and faders and the OB Comps, is it seems that I am much more aware of little differences of amplitude and freq, both of which are good things.
Thx!
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Post by tasteliketape on Feb 8, 2018 12:34:00 GMT -6
I had a new Samson s patchbay , took me almost a year to find my level problem was a Chanel on the patchbay . Just didn’t think since it was new.
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Post by matt@IAA on Feb 8, 2018 12:38:31 GMT -6
For compressors, leave the compressor on auto makeup if it has then option. Or carefully match output level each time you make a compression change. The console will actually help with this a lot, if you maintain 0 VU on the channel and so on.
Then you’re not fooling yourself with loudness variations
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Post by kcatthedog on Feb 8, 2018 13:07:27 GMT -6
Good point, as I can obviously hear and see channel by channel the input and output.
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Post by jrasia on Feb 8, 2018 13:34:19 GMT -6
So, a question about mixing technique, not system set up. I am more a fan of eq first, then comp but I have never had 16 channels of 4 band eq and roughly 12 channels of different OB comps to mix with before I want to have fun learning how to use this well and on the one hand, also believe in, if it sounds right, it is right, but any advice about approach and learning how to better hear the differences in my various compressors etc. ? I think the first big lesson learned using the delta EQ, balance and faders and the OB Comps, is it seems that I am much more aware of little differences of amplitude and freq, both of which are good things. Thx! Delta's have wire jumpers on the PCB that you have to cut and move to new positions if you want to change the EQ pre or post insert. Not sure if you are using outboard on your inserts or not Matthew. Also, in general eqing, less is more, more or less. Not a big fan of big cuts and boosts unless there is seriously something wrong. The phase button is probably just as effective sometimes.
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Post by kcatthedog on Feb 8, 2018 13:43:33 GMT -6
Understood thx! Yes, I know about the internal jumper ( mine are are all at factory default of Post).
I meant external, as I am using the insert to send receive my daw out to the delta eq, patch to OB comp and then back to the daw. Thanks to Wiz, I have a system of 3 Samsung S patchbays: one is the insert send receive normalled, the second are the delta direct out and interface ins normalled and 3rd is all fx and pre outs.
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Post by Martin John Butler on Feb 8, 2018 19:33:47 GMT -6
Compressors by nature change EQ. So you can EQ after compression, and perhaps not need as much EQ.
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Post by rowmat on Feb 8, 2018 19:47:06 GMT -6
Compressors by nature change EQ. So you can EQ after compression, and perhaps not need as much EQ. That's where inserting an EQ into the sidechain gives you greater control of how the comp reacts to particular frequencies in the main signal path. Obviously high passing the side chain when compressing a kick drum for instance prevents the comp from reacting too aggressively to the low end. The 'Low Cut' and 'SPR' controls on Aphex Expressors while not variable help to the preserve the low end and work great on kick drums etc while the high frequency expander helps the high end. Under rated and still relativey cheap but prices are creeping up.
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Post by mrholmes on Feb 9, 2018 6:25:07 GMT -6
My advice is to pick a digital reference level for 0VU and calibrate your system. I wish there was a single article that explains it that I could refer you to, but I can't find one. There is one brilliant blog article about calibrating the interface to the hardware.... ericbeam.com/?p=3224
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Post by kcatthedog on Feb 9, 2018 7:19:57 GMT -6
Wiz’s method above achieves unity gain. I just need to mark each knob or decide to only use the delta for mixing (ob pres for pres) and set and forget gain x channel ?
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