matta
Well-known member
Guys,
Level reference continue to confuse the crap out of me: dBu, dBV, add in +-4dBu and -10dBu and INPUT/OUTPUT impedances not forgetting the various TYPES of pads (T,L,O,U etc) and you get a whole lot of crazy.... at least for me....
I'm trying to get to the bottom of this and would love some help... here is what I DO know... in a balanced system a typical "U" pad will work, albeit asymmetrically but this is fine for attenuating a LINE LEVEL signal INTO a MIC INPUT LEVEL.
Ok, so in a typical situation where you would have a LINE LEVEL signal, -10dBV / 10K OHMS from a prosumer signal source you would need to ATTENUATE/PAD the signal to match the MIC INPUT source impedance? Correct? Typically this is 30-40dB?
What happens in this situation where I have a +4dBV output from a PRO AUDIO sound card with an output impedance of 50-100 Ohms (like line level out of a mic pre I would guess)?
The way I understand it 'typically':
INSTRUMENT LEVEL = +1M OHMS
MIC LEVEL = 100+ OHMS
+4dBu BALANCED LINE LEVEL = 50 OHMS
-10dBV UNBALANCED LINE LEVEL = 10K OHMS
The weird thing is there doesn't seem to be and standard with manufactures RE giving these details away, some manuals have them others just broadly speak of +4dBu and-10dBV with no concern/indication of impedances etc.
Here is the predicament I find myself in, a client/friend has asked me to build him a pair of cables with prebuilt pads coming OUT of his Pro Tools hardware interface (according to the spec it is balanced +4dBV / 50 Ohms) INTO a Great River Mic Pre (can't seem to find the input specs on them) to add coloration to his stereo mix, recording the output back into Pro Tools.
So how does one go about working out how MUCH of a pad would be needed in a situation like this? Again sorry if it seems like such a basic questions but levels confuse me... still waiting for Kev's know it all primer!
Off tangent...
What confuses me is in a typical situation of a console less environment, it is more and more common for guys have racks of outboard gear and run a mic into a pre, then into an EQ then into the DAW... well if levels/impedances are correct then the output of the mic pre would be around 100 OHMS but the input of say an API 550EQ would be 10K Ohm and the output back to 50-100 OHMS when entering the DAW/Converters... weird and perplexing... doesn't this cause impedance mismatching/issues?
Thanks in advance!
Matt
Level reference continue to confuse the crap out of me: dBu, dBV, add in +-4dBu and -10dBu and INPUT/OUTPUT impedances not forgetting the various TYPES of pads (T,L,O,U etc) and you get a whole lot of crazy.... at least for me....
I'm trying to get to the bottom of this and would love some help... here is what I DO know... in a balanced system a typical "U" pad will work, albeit asymmetrically but this is fine for attenuating a LINE LEVEL signal INTO a MIC INPUT LEVEL.
Ok, so in a typical situation where you would have a LINE LEVEL signal, -10dBV / 10K OHMS from a prosumer signal source you would need to ATTENUATE/PAD the signal to match the MIC INPUT source impedance? Correct? Typically this is 30-40dB?
What happens in this situation where I have a +4dBV output from a PRO AUDIO sound card with an output impedance of 50-100 Ohms (like line level out of a mic pre I would guess)?
The way I understand it 'typically':
INSTRUMENT LEVEL = +1M OHMS
MIC LEVEL = 100+ OHMS
+4dBu BALANCED LINE LEVEL = 50 OHMS
-10dBV UNBALANCED LINE LEVEL = 10K OHMS
The weird thing is there doesn't seem to be and standard with manufactures RE giving these details away, some manuals have them others just broadly speak of +4dBu and-10dBV with no concern/indication of impedances etc.
Here is the predicament I find myself in, a client/friend has asked me to build him a pair of cables with prebuilt pads coming OUT of his Pro Tools hardware interface (according to the spec it is balanced +4dBV / 50 Ohms) INTO a Great River Mic Pre (can't seem to find the input specs on them) to add coloration to his stereo mix, recording the output back into Pro Tools.
So how does one go about working out how MUCH of a pad would be needed in a situation like this? Again sorry if it seems like such a basic questions but levels confuse me... still waiting for Kev's know it all primer!
Off tangent...
What confuses me is in a typical situation of a console less environment, it is more and more common for guys have racks of outboard gear and run a mic into a pre, then into an EQ then into the DAW... well if levels/impedances are correct then the output of the mic pre would be around 100 OHMS but the input of say an API 550EQ would be 10K Ohm and the output back to 50-100 OHMS when entering the DAW/Converters... weird and perplexing... doesn't this cause impedance mismatching/issues?
Thanks in advance!
Matt