Topic: Gain vs. Line Level

[Bluegrasser]

Hey Howdy Hey,
Im sure this has been covered many many times here but I can not seem to locate the thread that would help me.
Can anyone explain to a novice what "gain" is compared to "Line Level"
As I understand it, when using a preamp the gain boosts the mic level (low) to a line level (high).
When recording I want to get as much gain from the preamp (to boost as close to true line level) as I can with-out getting noise. I would also want to keep the line level on the recorder as low as possible. - That means adjusting the gain to peak the recorder at -12db to 0db - Is that correct?
OR
Do you adjust the line level on your recorder to peak the recorder at -12db to 0db once you set gain and if so how do you find out the optimum gain setting?
TIA to all
 

[page]

As I understand it, when using a preamp the gain boosts the mic level (low) to a line level (high).

correct.

When recording I want to get as much gain from the preamp (to boost as close to true line level) as I can with-out getting noise. I would also want to keep the line level on the recorder as low as possible.

Basically, yes.

That means adjusting the gain to peak the recorder at -12db to 0db - Is that correct?

Also, basically yes, do it on the preamp. The majority of the time, the gain on an separate preamp will produce better/cleaner/more pleasing gain than gain on a recorder's preamp stage (presuming it has on, sometimes it doesn't).

Do you adjust the line level on your recorder to peak the recorder at -12db to 0db once you set gain and if so how do you find out the optimum gain setting?
TIA to all

Generally not, no.

[fmaderjr]

I would also want to keep the line level on the recorder as low as possible.

True, but you need to be careful that the recorder is not attenuating much or at all. Ideally, you want the line level of the recorder set to unity gain (where the recorder is neither amplifying nor attenuating) so the you can get all your gain from your preamp.

If the recorder's line level is attenuating you will need more gain from the preamp than is necessary to reach your goal of -12 dB peaks, which could also add noise to the recording. And if the recorder is attenuating a lot it's a recipe for disaster. You may need so much gain from the preamp to reach -12 dB peaks that the preamp may clip and cause the recording to be distorted (even though your recorder will be showing peaks of -12 dB).

What recorder will you be using? Someone here will probably be able to recommend a line level setting where you will be at (or at least close to) unity gain. That setting will most likely be somewhere near the middle of the gain setting or a little below and will likely be well above the recorder's minimum gain setting. For example the Edirol R-09HR has gain settings that go from 1-100 and unity gain has been determined to be around 38-40. Below that you are attenuating.

[beatkilla]

What is the unity setting on Sony m10 for line input.....4??I just got the sonic studios dsm 6 and pa 3sx.The pa3sx pre has ony 3 gain setting 20db  28db  36db.

[fmaderjr]

What is the unity setting on Sony m10 for line input.....4??I just got the sonic studios dsm 6 and pa 3sx.The pa3sx pre has ony 3 gain setting 20db  28db  36db.

I use 4 myself. I think some here have said unity gain is 4 and other think it is 3, but 4 has worked well enough for me. I'm sure 3 also works well.

Do your mics have a 1/8 mini-plug or do they need something different to connect to the preamp? I'm sure you're aware that when you are recording something very loud and don't need much gain, if your mics have a 1/8 mimi-plug you can run the mics straight into the M10's mic input. According to Guysonic, the M10 is one of the few recorders whose plug in power will perfectly power Sonic Studios mics. I've run an older set of Sonic Studios mics directly into my M10 with good results.

[beatkilla]

They terminate in mini xlr.I'll try the setting of 4 on my outings.

[cashandkerouac]

What is the unity setting on Sony m10 for line input.....4??I just got the sonic studios dsm 6 and pa 3sx.The pa3sx pre has ony 3 gain setting 20db  28db  36db.

I use 4 myself. I think some here have said unity gain is 4 and other think it is 3, but 4 has worked well enough for me. I'm sure 3 also works well.

Do your mics have a 1/8 mini-plug or do they need something different to connect to the preamp? I'm sure you're aware that when you are recording something very loud and don't need much gain, if your mics have a 1/8 mimi-plug you can run the mics straight into the M10's mic input. According to Guysonic, the M10 is one of the few recorders whose plug in power will perfectly power Sonic Studios mics. I've run an older set of Sonic Studios mics directly into my M10 with good results.

i have found that unity gain on the M10 is bwteen "4" and "5".  "3" is definitely low, but you can get away with it.  below "3" and you're definitely asking for trouble.

i usally set my M10 to "4.5" and then adjust gain on my preamp to dial in final levels.  sometimes i end up setting my preamp at it's most minimal gain setting, but that's ok.   

[F.O.Bean]

My m10s are set at 3.5

[Bluegrasser]

Thank you Page and fmaderjr .... I am starting to get a grasp of it.
To answer your Q? I am using a dr40.
I found this pdf that has some info on unity gain for the dr40. It states I should set line level to 0 and volume to 4 below peak. This does not sound correct (or a very technical). Can anyone confirm/deny this?
http://faculty.uncsa.edu/film/1801/fall-2012/camera_sound_instructions_2012.pdf

[cashandkerouac]

My m10s are set at 3.5

Bean:  i've never had anything bad happen with my M10 set above "3", but "3.5" is a somewhat aggressive setting.     

[F.O.Bean]

My m10s are set at 3.5

Bean:  i've never had anything bad happen with my M10 set above "3", but "3.5" is a somewhat aggressive setting.     

What is yours set to? Mine are at 3.5 and I adjust gain on the preamp

[robeti]

Anyone know the unity setting on Roland R-05 for line input?

[fmaderjr]

Thank you Page and fmaderjr .... I am starting to get a grasp of it.
To answer your Q? I am using a dr40.
I found this pdf that has some info on unity gain for the dr40. It states I should set line level to 0 and volume to 4 below peak. This does not sound correct (or a very technical). Can anyone confirm/deny this?
http://faculty.uncsa.edu/film/1801/fall-2012/camera_sound_instructions_2012.pdf

I can't make anything out of that pdf.....

I've never heard anyone discuss unity gain for the dr40, but some members here use them so someone may be able to give you a setting that seems to work well.

[DSatz]

Gain is just another word for amplification. When dealing with microphones and preamps, the issue is voltage rather than current or power, so an amplifier's gain is basically the factor by which it multiplies the input signal voltage. For example, if at a given moment an amplifier has 10 mV at its input and 100 mV at its output, then it has a voltage gain of 10.

Most often, people use decibels when describing the gain of an audio circuit; that factor of 10 in voltage would correspond to a gain of 20 dB.

> When recording I want to get as much gain from the preamp (to boost as close to true line level) as I can with-out getting noise. I would also want to keep the line level on the recorder as low as possible.

Those are generalizations, and I'd say that the first one is somewhat better than the second one, though neither one is all that great. You didn't mention overload, yet 6 dB of added noise (for example) is certainly preferable to 3 dB of hard clipping. So the overload limit is a more important consideration than noise alone, and limits your range of choices more severely as a consequence.

Here is my preferred generalization: Well-designed, well-chosen audio equipment gives you some latitude in your gain settings without forcing you to pay a serious price in terms of noise or risk of overload. You shouldn't have to keep the input gain setting on the recorder low and "swamp" its input with large signals from a preamp to get a good recording; nor should you have to do the opposite. There should be a useful range in which you can set the gains of the two pieces of equipment and still get optimal or nearly optimal results.

The assumption that the "unity" gain setting of a recorder (line input voltage = line output voltage) will give you the best signal-to-noise ratio is another generalization, unfortunately not one that's based on anything very reliable. There's no necessary relationship between that particular gain setting--which depends on design variables that are purely within the recorder--and the best possible combination of preamp and recorder gain settings, which depends on a larger, more complex set of variables. The two things have nothing directly to do with one another.

--best regards