Is my recording level too low? Is my amplified level ok?

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J,R,D, Ltd
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Is my recording level too low? Is my amplified level ok?

Post by J,R,D, Ltd » Tue Jan 18, 2011 7:00 am

Hey guys,
I wanted to get a professional opinion on my recording level. I have the recording volume in Audacity set all the way down (raising it all the way up doesn't appear to make much of a difference on the graph) and the volume on the mixer is set to about a medium level I think. (not at the auditorium so I don't remember exactly)

You can see the levels in the pictures I attached, I have been amplifying it because it is definitely low when I play it back. I guess a sound sample would have been a better idea then the images but I didn't think of that at the time and it is to late to do it tonight, I can upload sound samples tomorrow/later today as it is.

Thanks!
(it seems to be showing the images backwards with the first image I uploaded on the bottom)
[moderator note] I've reversed the order of the images using the "place inline" button
audio sample1 1-17-11.png
This first sample is from a loud part of my recording.
audio sample1 1-17-11.png (30.54 KiB) Viewed 3126 times
audio sample2 1-17-11.png
This second sample is from a softer part of my recording and how most of it goes.
audio sample2 1-17-11.png (19.22 KiB) Viewed 3124 times

steve
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Re: Is my recording level too low? Is my amplified level ok?

Post by steve » Tue Jan 18, 2011 8:18 am

The recording level looks fine - the peaks in the loud part are at about -6 dB (0.5 on the linear scale) which is ideal. However, the tops of the peaks look flat, which indicates that the sound is being clipped/distorted before it gets to Audacity.

If you give full details of the equipment used and how it is all set up we may be able to suggest why that may be occurring.
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bgravato
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Re: Is my recording level too low? Is my amplified level ok?

Post by bgravato » Tue Jan 18, 2011 12:48 pm

If you apply the amplify effect with the default options it will amplify the sound so that the new peak will be 0dB, this is the maximum you should have, above that you get distortion. Some people prefer to be a bit more conservative (like me) and amplify to a new peak slightly below 0dB (usually somewhere between -2dB and -0.3dB).

The levels in the first image look perfect, except for the flat tops which suggests clipping prior to audacity recording, as Steve suggested. Without knowing which equipment you used and how you have it connected we can't say how you can solve that.

The recording level on the second image look a bit too low.

If your recording has a lot of dynamics (some parts sounding quite loud and other parts sounding very quiet) and you want to narrow the volume differences between quiet and loud parts then you need to use dynamic compression. If you search the forum for dynamic compression you'll find a lot of threads about it.
Include as much details as you can in your post (Audacity version, Operating System, Equipment used, etc).
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lturudic
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Re: Is my recording level too low? Is my amplified level ok?

Post by lturudic » Tue Jan 18, 2011 2:46 pm

I think best is use function normalize in effect.
Mark "remove any DC offset" and mark normalize ax.amplitude on 1,0dB.

After this setings you have exelent sound with max. volume and without distorzion.

waxcylinder
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Re: Is my recording level too low? Is my amplified level ok?

Post by waxcylinder » Tue Jan 18, 2011 3:06 pm

Just to expand a bit on lturudic's advice:

1) It is generally thought best practice to apply DC offset correction as the first thing you do immediately after capture - apply no amplification at that stage. You onlt need to do this if your signal is carrrying some DC - you can see this when the waveform is off-centre from the zero line.

2) Normalization or Amplification is normall6y the last editing step after all other editing, i.e just prior to exporting your production audio files. Amplify and Normalize in Audacity both do similar, but subtly different things. Amplify works on both channels of a stereo signal equally whereas Normalize works on each of the two channels separately. So Normalize is good if you have unbalanced equipment in your recording chain - otherwise it is better to use Ampliffy so that you do not change or damage the stereo image.

3) the advice not to amplify/normalize up to odB is good - although this is the theoretical maximum peak loudness to avoid clippin some audio players do not like playing audio files with 0dB peaks. ltuuredic recommends -1dB, I am a bit more conservative peaking at -2.0db (but even than my son complains that my recordings are too loud on his iPod - so-2.0 dB should be plenty loud enough :) ).

WC
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J,R,D, Ltd
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Re: Is my recording level too low? Is my amplified level ok?

Post by J,R,D, Ltd » Wed Jan 19, 2011 7:15 am

steve wrote:The recording level looks fine - the peaks in the loud part are at about -6 dB (0.5 on the linear scale) which is ideal. However, the tops of the peaks look flat, which indicates that the sound is being clipped/distorted before it gets to Audacity.

If you give full details of the equipment used and how it is all set up we may be able to suggest why that may be occurring.
Hmm, yea the peaks are a little flat. The loud part was a video being played on another laptop going through the mixer, more details below.
bgravato wrote:If you apply the amplify effect with the default options it will amplify the sound so that the new peak will be 0dB, this is the maximum you should have, above that you get distortion. Some people prefer to be a bit more conservative (like me) and amplify to a new peak slightly below 0dB (usually somewhere between -2dB and -0.3dB).

The levels in the first image look perfect, except for the flat tops which suggests clipping prior to audacity recording, as Steve suggested. Without knowing which equipment you used and how you have it connected we can't say how you can solve that.

The recording level on the second image look a bit too low.

If your recording has a lot of dynamics (some parts sounding quite loud and other parts sounding very quiet) and you want to narrow the volume differences between quiet and loud parts then you need to use dynamic compression. If you search the forum for dynamic compression you'll find a lot of threads about it.
Is this the dynamic compression you are talking about? http://pdf23ds.net/software/dynamic-compressor/
The softer part in the second image is our pastor speaking, I guess I should raise his recording volume to match up closer to the video. I think the reason I have him down is because occasionally he accidentally blows on his wireless mic or saliva hits it or something and it makes a loud sound. It's hard to explain but I could easily find a clip of it if you wanted to hear.
waxcylinder wrote:Just to expand a bit on lturudic's advice:

1) It is generally thought best practice to apply DC offset correction as the first thing you do immediately after capture - apply no amplification at that stage. You onlt need to do this if your signal is carrrying some DC - you can see this when the waveform is off-centre from the zero line.

2) Normalization or Amplification is normall6y the last editing step after all other editing, i.e just prior to exporting your production audio files. Amplify and Normalize in Audacity both do similar, but subtly different things. Amplify works on both channels of a stereo signal equally whereas Normalize works on each of the two channels separately. So Normalize is good if you have unbalanced equipment in your recording chain - otherwise it is better to use Ampliffy so that you do not change or damage the stereo image.

3) the advice not to amplify/normalize up to odB is good - although this is the theoretical maximum peak loudness to avoid clippin some audio players do not like playing audio files with 0dB peaks. ltuuredic recommends -1dB, I am a bit more conservative peaking at -2.0db (but even than my son complains that my recordings are too loud on his iPod - so-2.0 dB should be plenty loud enough :) ).

WC
Maybe I should explain a little about what I am doing before I start describing the equipment so I don't come off as being rich, or being rich before starting all this, lol. :lol:

I volunteer at my church as the soundboard operator and do pretty much everything related to it. So this equipment is not mine except for the laptop I'm using to record but I can change anything I need/want to.

The mixer is a Yamaha MG32/14FX, I don't recall what the amps are but I figure that is unimportant for this, I can get the information next Sunday if it would be helpful though.

We have multiple mics and instruments on stage totaling 4 plus on average.

For videos we run the output (from headphone jack) from our laptop controlling the overhead into Channel 18 Input B on the mixer. (The loud part shown in the first image is from here)

We have a wireless mic for our pastor but I do not remember the make or model of it, I know I was unable to find a manual online for it from the manufacturer. It is on Channel 23 Input A on the mixer.(The softer part in the second image is from here)

Aux 1 and 2 are monitors on stage and I am using Aux 3 for recording, it is mono so I am mixing everything down to one channel and sending it to the recording laptop through it's microphone port configured as line in.

I plan to make a desktop with 4-6 sound cards configured with JACK and the el cheapo mod and record each instrument and mic on a separate channel but I have to find the right parts first.

Well I think that's everything, if I forgot something or you want to know something else just say so and I will give whatever information I can.

Trebor
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Re: Is my recording level too low? Is my amplified level ok?

Post by Trebor » Wed Jan 19, 2011 7:47 am

J,R,D, Ltd wrote:... the reason I have him down is because occasionally he accidentally blows on his wireless mic or saliva hits it or something and it makes a loud sound.
It's hard to explain but I could easily find a clip of it if you wanted to hear.
Maybe the "loud sound" is sibilance, which is treatable ... http://forum.audacityteam.org/viewtopic ... 26&t=51535

bgravato
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Re: Is my recording level too low? Is my amplified level ok?

Post by bgravato » Wed Jan 19, 2011 9:14 am

Trebor wrote:
J,R,D, Ltd wrote:... the reason I have him down is because occasionally he accidentally blows on his wireless mic or saliva hits it or something and it makes a loud sound.
It's hard to explain but I could easily find a clip of it if you wanted to hear.
Maybe the "loud sound" is sibilance, which is treatable ... http://forum.audacityteam.org/viewtopic ... 26&t=51535
Or he might need a popfilter between him and the mic.
J,R,D, Ltd wrote:Is this the dynamic compression you are talking about? http://pdf23ds.net/software/dynamic-compressor/
Yes, that's the most popular dynamic compressor around here. You have another one built in audacity, but chris' gets best reviews from the elves.
Include as much details as you can in your post (Audacity version, Operating System, Equipment used, etc).
Please post your question in the appropriate forum (regarding audacity version and operating system).

J,R,D, Ltd
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Re: Is my recording level too low? Is my amplified level ok?

Post by J,R,D, Ltd » Thu Jan 20, 2011 5:27 am

Trebor wrote:
J,R,D, Ltd wrote:... the reason I have him down is because occasionally he accidentally blows on his wireless mic or saliva hits it or something and it makes a loud sound.
It's hard to explain but I could easily find a clip of it if you wanted to hear.
Maybe the "loud sound" is sibilance, which is treatable ... http://forum.audacityteam.org/viewtopic ... 26&t=51535
It probably is partially related to sibilance, I will have to try that.

bgravato wrote:
Trebor wrote:
J,R,D, Ltd wrote:... the reason I have him down is because occasionally he accidentally blows on his wireless mic or saliva hits it or something and it makes a loud sound.
It's hard to explain but I could easily find a clip of it if you wanted to hear.
Maybe the "loud sound" is sibilance, which is treatable ... http://forum.audacityteam.org/viewtopic ... 26&t=51535
Or he might need a popfilter between him and the mic.
J,R,D, Ltd wrote:Is this the dynamic compression you are talking about? http://pdf23ds.net/software/dynamic-compressor/
Yes, that's the most popular dynamic compressor around here. You have another one built in audacity, but chris' gets best reviews from the elves.
Well there is a little foam cushion/filter on the mic which helped when we put that back on but did not eliminate it. Maybe we need a better filter?

I need to play around with that dynamic compressor too.

lturudic
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Re: Is my recording level too low? Is my amplified level ok?

Post by lturudic » Thu Jan 20, 2011 2:09 pm

1) It is generally thought best practice to apply DC offset correction as the first thing you do immediately after capture - apply no amplification at that stage. You onlt need to do this if your signal is carrrying some DC - you can see this when the waveform is off-centre from the zero line.

2) Normalization or Amplification is normall6y the last editing step after all other editing, i.e just prior to exporting your production audio files. Amplify and Normalize in Audacity both do similar, but subtly different things. Amplify works on both channels of a stereo signal equally whereas Normalize works on each of the two channels separately. So Normalize is good if you have unbalanced equipment in your recording chain - otherwise it is better to use Ampliffy so that you do not change or damage the stereo image.

3) the advice not to amplify/normalize up to odB is good - although this is the theoretical maximum peak loudness to avoid clippin some audio players do not like playing audio files with 0dB peaks. ltuuredic recommends -1dB, I am a bit more conservative peaking at -2.0db (but even than my son complains that my recordings are too loud on his iPod - so-2.0 dB should be plenty loud enough :) ).

Thanks for the advice about the difference between normalization and amplify.
It is logical to distort stereo images, I don t thinking about.
I have very little experience, I ripped three LP.
Peaks'd left at 1 db because I love to listen to loud (100 watts RMS), so the amplifier would fall in clliping.

If you have more useful tips for ripps prayed for them.

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