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Old 22nd December 2010, 12:00 PM   #2861
SY is offline SY  United States
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Quote:
Originally Posted by panomaniac View Post
I do see clipping sometimes, tho. So that's either the recording or the player.
I know you have a copy of Robert Ellis's album- check out "Bonnie" for a real red light special. I think he now knows to do better on the next album.
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Old 22nd December 2010, 10:35 PM   #2862
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Quote:
Originally Posted by slacker0001 View Post
How do you guys set the input levels when running fully digital?
It seems easy to get clipping ?
Slacker, I have the same issue :-(
I cannot use digital input because my digital source always seems to clip the DCX input.. I do not like using the DCX to attenuate the input signal, and my source has no output level control..

I mentioned on another thread whether changing 110 ohm resistor on the DCX DSP board to 75 ohm would help with this as I am using SDiF not AES/EBU, but i was told it wouldn't help at all, so I'm stuck using the analog input, which isn't too bad as I'm using the Didden active i/o mod..

Murphy
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Old 22nd December 2010, 11:09 PM   #2863
SY is offline SY  United States
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If seeing the red light come on is worrisome, then you can dial down the input gain.
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Old 23rd December 2010, 01:01 AM   #2864
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Thing that I don't understand is if I turn down the input gain, I am doing so in the digital domain, not the analog domain. So if I have my input gain set to 0 dB but am clipping, how would turning down the gain help against clipping? It has already clipped at the A/D, no ?

Considering a massive upgrade of my "already modded" DCX - going to SPDIF input with all xfmr based outputs to passive ganged volume controls and even then maybe to a preamp (amp is difficult load).
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Old 23rd December 2010, 03:31 AM   #2865
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Quote:
Originally Posted by zigzagflux View Post
Thing that I don't understand is if I turn down the input gain, I am doing so in the digital domain, not the analog domain. So if I have my input gain set to 0 dB but am clipping, how would turning down the gain help against clipping? It has already clipped at the A/D, no ?
I dont quite understand it completely myself..??
But DCX uses 'bit stripping' for level attenuation,, so definately don't use the DCX level controls for below 0dB!!

Murphy
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Old 23rd December 2010, 03:53 AM   #2866
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Fellas,

When using the digital input, the input clipping indicators are completely unreliable for identifying actual clipping. They can be flashing yellow/red all the time and you still might not be clipping. This question has already been asked and answered numerous times right here in this interminably long thread.

The only reliable clipping indicators on the DCX are the six OUTPUT indicators. If those are flashing red then you can be assured you are waveform clipping.

Cheers,

Dave.
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Old 23rd December 2010, 04:29 AM   #2867
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Originally Posted by Davey View Post
Fellas,

When using the digital input, the input clipping indicators are completely unreliable for identifying actual clipping. They can be flashing yellow/red all the time and you still might not be clipping. This question has already been asked and answered numerous times right here in this interminably long thread.

The only reliable clipping indicators on the DCX are the six OUTPUT indicators. If those are flashing red then you can be assured you are waveform clipping.

Cheers,

Dave.
Thanks Dave,,

It's pretty amaxing to have a thread going strong for so many years!!
I just joined recently,, it's too much to try and catch up on everything in this thread

So, you suggest dont worry if input lights a flashing red?? Is this only for digital, or also for analog??

Ta
Murphy
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Old 23rd December 2010, 05:58 AM   #2868
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Quote:
Originally Posted by MurphyUHF10 View Post
Slacker, I have the same issue :-(
I cannot use digital input because my digital source always seems to clip the DCX input.. I do not like using the DCX to attenuate the input signal, and my source has no output level control..

I mentioned on another thread whether changing 110 ohm resistor on the DCX DSP board to 75 ohm would help with this as I am using SDiF not AES/EBU, but i was told it wouldn't help at all, so I'm stuck using the analog input, which isn't too bad as I'm using the Didden active i/o mod..

Murphy
If you clip with digital in, it is clipping on the source! Meaning, your source is recorded with lots of 'max' digital codes. No amount of attenuation will change that. You can decrease the input level on the DCX and it will sound less loud but the clipping will not be removed because it is on the source signal. The signal is coded in the digital stream and not in the actual voltage level of the S/PDIF or AES/EBU signal.
What you should do is find a CD or whatever that has been decently recorded, admittedly not so easy with recent CD material.

jan didden
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Old 23rd December 2010, 09:23 AM   #2869
AndrewT is offline AndrewT  Scotland
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Default digital input

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Originally Posted by janneman View Post
If you clip with digital in, it is clipping on the source! Meaning, your source is recorded with lots of 'max' digital codes.
I think you are saying the clipping indicator for a digital signal is detect "max" digital codes.
Have I read this correctly?
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Old 23rd December 2010, 09:17 PM   #2870
Davey is offline Davey  United States
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Quote:
Originally Posted by MurphyUHF10 View Post
Thanks Dave,,

It's pretty amaxing to have a thread going strong for so many years!!
I just joined recently,, it's too much to try and catch up on everything in this thread

So, you suggest dont worry if input lights a flashing red?? Is this only for digital, or also for analog??

Ta
Murphy
I wouldn't say don't worry about it, but be aware of it. It's not unusual to see the input indicators flashing red quite a bit when you have program material recorded at (and close to) 0dbFS. Jan is correct that this "clipping" is "embedded" in the source signal. You could digitally attenuate the signal before it enters the DCX and the red clipping indicators will no longer illuminate, but you're not correcting "clipping" behavior by doing that.

It's still not a bad idea to attenuate digital inputs by 3db or so because this can alleviate waveform clipping downstream in the DCX when you have engaged crossover filters (or other EQ) that alter the crest factor to a higher peak level. In this case also, the output channel clipping indicators are a good indicator of possible problems.
Also, with a stock DCX, there's an op-amp stage in the output analog circuitry that's very close to clipping at max levels. The modified DCX solutions (like Jan's) solve that problem and many others.

Based on your avatar, it appears you already have a Didden modified DCX? I'm not sure of the clipping behavior of the analog input portion of that unit.

Cheers,

Dave.
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