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Levels to use when recording vinyl, do I need amp before line-in, etc., [split from “Archiving vinyl once only 96/24?”/thread 100121/TOS #5]
zerowalker
post Mar 30 2013, 03:45
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Little off topic maybe, but if you use Line In on a compture to record.
Is the volume of that Line In the same as using an Amp?
Or is the volume corrected after it has been digitalized?

Just wondering as i also want to maximise ADC coverage.
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AndyH-ha
post Mar 30 2013, 09:13
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A professional line level input is just an input. It may be switchable between the two line level standards, +4dBu and -10dBV (professional and consumer), but it is not variable. In a mixer interface there could be a line level preamp (generally providing +10dB or +12dB gain and some larger attenuation), but that is an extra, not actually part of a real line level input. Gaming and entertainment cards are a whole different thing and must be investigated individually.

The input controls on most ADC are digital, after the signal has been sampled, and are best set at maximum. They cannot prevent clipping, and they cannot improve on the ADC output.

Mostly, for taking the signal from a phono preamp, the consumer level line-in is appropriate. The +4dBu input expects a much higher level signal and would thus be recording way down from 0dBfs of the ADC, but there are exceptions.

The outputs of both phono cartridges and phono preamps vary considerably from one construction to another. Sometimes the combination you happen to have produces a very good signal for your ADC line in, sometimes you need to adjust up or down.

If the signal level is too high, it will clip in the ADC and that cannot be corrected post recording; it must be done in the analogue domain.

Signals that peak as much as 20dBfs down are probably quite ok, and can be normalized after recording. If that doesn't satisfy you, or if you need to attenuate the signal before the ADC, you need a line level preamp between the phono preamp and the line level ADC input. A small analogue mixer is usually the least expensive fix.

If you just need attenuation, a passive volume control, or even a fixed resistor attenuator, isn't hard to implement.
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Paul Sanders
post Mar 30 2013, 10:37
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QUOTE (AndyH-ha @ Mar 30 2013, 09:13) *
The input controls on most ADC are digital, after the signal has been sampled, and are best set at maximum. They cannot prevent clipping, and they cannot improve on the ADC output.

You keep saying that but it's not true. What makes you believe that?


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I am an independent software developer (VinylStudio) based in UK
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zerowalker
post Mar 30 2013, 11:01
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QUOTE (Paul Sanders @ Mar 30 2013, 10:37) *
QUOTE (AndyH-ha @ Mar 30 2013, 09:13) *
The input controls on most ADC are digital, after the signal has been sampled, and are best set at maximum. They cannot prevent clipping, and they cannot improve on the ADC output.

You keep saying that but it's not true. What makes you believe that?


Wait, so it isnīt true?

Is the volume amplifying the signal before itīs converted?
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Paul Sanders
post Mar 30 2013, 11:11
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QUOTE (zerowalker @ Mar 30 2013, 10:01) *
Is the volume amplifying the signal before itīs converted?

Or attenuating, yes.


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zerowalker
post Mar 30 2013, 12:17
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QUOTE (Paul Sanders @ Mar 30 2013, 11:11) *
QUOTE (zerowalker @ Mar 30 2013, 10:01) *
Is the volume amplifying the signal before itīs converted?

Or attenuating, yes.


So, an amp isnīt needed at all before the Line In?
Except if the signal is still to low or hight no matter the volume.
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Paul Sanders
post Mar 30 2013, 13:24
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QUOTE (zerowalker @ Mar 30 2013, 11:17) *
So, an amp isnīt needed at all before the Line In?
Except if the signal is still to low or high no matter the volume.

That's correct. It's almost always unnecessary, with any reasonable line-level source and any reasonable sound card. Just adjust the recording level slider to get a decent level, as people have recommended earlier in this thread.

If recording from a phono source, you still need a phono preamp of course, and some budget / semi-budget USB devices have a fixed recording level, sad to say. What then causes a lot of confusion is that Windows Vista and later offer a digital slider, which is unhelpful and unwanted (VinylStudio offers a button in this case to set the digital gain to 1, with a recommendation to use it, and tough luck if it clips).


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zerowalker
post Mar 30 2013, 13:28
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QUOTE
What then causes a lot of confusion is that Windows Vista and later offer a digital slider


What do you mean?
Is the volume slider in Volume(in sound settings) Digital?
Or am i confusing things.

QUOTE
If recording from a phono source, you still need a phono preamp of course


May be stupid here, but isnīt Phono = RCA?
Why do you need an amp for that?

This post has been edited by db1989: Mar 30 2013, 14:52
Reason for edit: deleting pointless full quote of above post
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Paul Sanders
post Mar 30 2013, 13:50
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QUOTE (zerowalker @ Mar 30 2013, 12:28) *
What do you mean?
Is the volume slider in Volume(in sound settings) Digital?
Or am i confusing things.

I'm referring to the recording level slider, and it's digital only in the case where the sound card (or, in practise, USB device) has no hardware input level control. I told you it was confusing, what they (MS) have done is daft.

QUOTE (zerowalker @ Mar 30 2013, 12:28) *
May be stupid here, but isnīt Phono = RCA?
Why do you need an amp for that?

By 'phono source', I meant an unamplified pickup cartridge. You need a phono preamp for that to boost the signal to line level. USB turntables contain one, before the ADC and USB controller chip. Some conventional turntables now contain one too, just to muddy the waters.


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zerowalker
post Mar 30 2013, 14:15
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But, doesnīt that then mean that if i increase the recorder slider on my line in, it only changes the digital volume, not the analogue before the conversion?

Not sure what you mean with unamplified, when is it that?
Is a normal VCR output amplified for example?

Sorry, many terms i am not familiar with.

This post has been edited by db1989: Mar 30 2013, 14:52
Reason for edit: as above
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Posts in this topic
- zerowalker   Levels to use when recording vinyl, do I need amp before line-in, etc.   Mar 30 2013, 03:45
- - AndyH-ha   A professional line level input is just an input. ...   Mar 30 2013, 09:13
|- - Paul Sanders   QUOTE (AndyH-ha @ Mar 30 2013, 09:13...   Mar 30 2013, 10:37
|- - zerowalker   QUOTE (Paul Sanders @ Mar 30 2013, 10:37)...   Mar 30 2013, 11:01
||- - Paul Sanders   QUOTE (zerowalker @ Mar 30 2013, 10:01) I...   Mar 30 2013, 11:11
||- - zerowalker   QUOTE (Paul Sanders @ Mar 30 2013, 11:11)...   Mar 30 2013, 12:17
||- - Paul Sanders   QUOTE (zerowalker @ Mar 30 2013, 11:17) S...   Mar 30 2013, 13:24
||- - zerowalker   QUOTE What then causes a lot of confusion is that ...   Mar 30 2013, 13:28
||- - Paul Sanders   QUOTE (zerowalker @ Mar 30 2013, 12:28) W...   Mar 30 2013, 13:50
||- - zerowalker   But, doesnīt that then mean that if i increase the...   Mar 30 2013, 14:15
||- - Paul Sanders   QUOTE (zerowalker @ Mar 30 2013, 13:15) B...   Mar 30 2013, 14:33
||- - zerowalker   Ah, so XP only showed the slider when it was ...   Mar 30 2013, 14:36
||- - julf   QUOTE (zerowalker @ Mar 30 2013, 14:36) W...   Mar 30 2013, 14:47
||- - Paul Sanders   QUOTE (zerowalker @ Mar 30 2013, 13:36) A...   Mar 30 2013, 16:58
|- - aztec_mystic   QUOTE (Paul Sanders @ Mar 30 2013, 10:37)...   Mar 30 2013, 14:44
||- - Paul Sanders   QUOTE (aztec_mystic @ Mar 30 2013, 13:44)...   Mar 30 2013, 16:30
||- - Paul Sanders   OK, I have written a little utility to report whet...   Mar 30 2013, 19:08
||- - Paul Sanders   (Edit:) Added a 'set digital gain to 1' bu...   Mar 30 2013, 20:34
||- - zerowalker   Thanks for the software, it showed that all of min...   Mar 31 2013, 07:37
|- - 2Bdecided   QUOTE (Paul Sanders @ Mar 30 2013, 09:37)...   Mar 30 2013, 20:20
|- - Paul Sanders   QUOTE (2Bdecided @ Mar 30 2013, 19:20) Be...   Mar 30 2013, 20:29
- - zerowalker   Not sure i understood all that. But atleast i und...   Mar 30 2013, 09:44
- - aztec_mystic   Thanks for this tool! This is from my laptop (...   Mar 30 2013, 19:52
- - AndyH-ha   If the OP question was primarily about a phono pre...   Mar 30 2013, 21:05
|- - Paul Sanders   QUOTE (AndyH-ha @ Mar 30 2013, 20:05...   Mar 30 2013, 21:29
- - AndyH-ha   You disagree because you think the schematics lie?...   Mar 31 2013, 07:52
- - Paul Sanders   QUOTE (AndyH-ha @ Mar 31 2013, 06:52...   Mar 31 2013, 11:27
- - aztec_mystic   System 2: Traktor Kontrol S4 Ch C (Kontrol S4 WDM...   Mar 31 2013, 11:45
- - Paul Sanders   Interesting. Thank you for posting.   Mar 31 2013, 12:26


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