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#1
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Is it better to increase the gain on my Zoom in situations where sound levels
are low, or should I leave the gain lower and then normalize the recording later on? Which produces less noise in the end result? Or do they both amount to the same thing? |
#2
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On Mar 23, 12:42*am, Mxsmanic wrote:
Is it better to increase the gain on my Zoom in situations where sound levels are low, or should I leave the gain lower and then normalize the recording later on? Which produces less noise in the end result? Or do they both amount to the same thing? Increase the gain. Peace, Paul |
#3
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Mxsmanic wrote:
Is it better to increase the gain on my Zoom in situations where sound levels are low, or should I leave the gain lower and then normalize the recording later on? There is no single answer to this. Optimum is to set the gain right. If you can't get near the "upper bit" with available input signal you should - in my opinion - investigate whether the external pre you are using is proper for the task. Which produces less noise in the end result? Or do they both amount to the same thing? I don't know what Zoom device you have. I don't know what microphone(s) you have. I don't know which external pre you are using. I don't know what you are recording. Kind regards Peter Larsen |
#4
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Peter Larsen writes:
There is no single answer to this. Optimum is to set the gain right. If you can't get near the "upper bit" with available input signal you should - in my opinion - investigate whether the external pre you are using is proper for the task. OK I don't know what Zoom device you have. I don't know what microphone(s) you have. I don't know which external pre you are using. I don't know what you are recording. H4n, with its built-in microphones. Nothing external. Mostly city noises, like traffic, or sounds in a park or on a bridge, etc. If there's no fixed answer to this, is there an experiment that I can do that would allow me to find the answer? For example, with digital cameras, you can take a picture of darkness (lens covered) and then pull the result into Photoshop and force the pixel values to span their full scale, producing a visible pattern of weak pixels, if any. I don't know if there's a way to "record silence" with built-in microphones, though. |
#5
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On Friday, 23 March 2012 06:42:33 UTC+1, Mxsmanic wrote:
Is it better to increase the gain on my Zoom in situations where sound levels are low, or should I leave the gain lower and then normalize the recording later on? Which produces less noise in the end result? Or do they both amount to the same thing? Increase gain, so that highest peaks are as close to zero as possible, but not cliping. So you have to make voluntary sfety margin, as small as you think will be enough. Also you can ride the gain during recording to keep general level steady, if applicable. Gain pot must not be crackling one, though. You can go external mic preamp route. In that case you set gain as suited for the main part, then, beteween preamp and recorder, insert 1. gate/ expander to cut the noise off/ make sound above threshold proportionaly louder and 2. compressor/ limiter, to keep general level steady and take care of peaks. Ha, do we have Pro user vs. pro equipment situation, or don't we? |
#6
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Soundhaspriority writes:
The two steps are not equivalent. Each has a different purpose. Which will produce less noise in the finished recording? Or will the amount of noise in the finished product be the same either way? It's mainly a concern for very quiet environments, such as inside a park. For other street noise, the sound levels are so high that any noise from the equipment is irrelevant. |
#7
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Luxey writes:
Increase gain, so that highest peaks are as close to zero as possible, but not cliping. So you have to make voluntary sfety margin, as small as you think will be enough. OK. So in a very quiet environment, it's better to crank the gain than to set it lower and normalize later on. Also you can ride the gain during recording to keep general level steady, if applicable. Gain pot must not be crackling one, though. The Zoom uses a small rocker button to adjust gain and unfortunately it makes a slight clinking noise if you adjust it during recording, but sometimes I do resort to that rather than start over. You can go external mic preamp route. In that case you set gain as suited for the main part, then, beteween preamp and recorder, insert 1. gate/ expander to cut the noise off/ make sound above threshold proportionaly louder and 2. compressor/ limiter, to keep general level steady and take care of peaks. Currently I am using only built-in mics for this type of field recording, for the sake of convenience (and I can't afford anything else, anyway). Ha, do we have Pro user vs. pro equipment situation, or don't we? I suspect that the recorder is much more professional than I am. It seems to produce very nice recordings. |
#8
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On 3/23/2012 5:29 AM, Mxsmanic wrote:
H4n, with its built-in microphones. Nothing external. Mostly city noises, like traffic, or sounds in a park or on a bridge, etc. Set the gain as best you can with the controls on the recorder. While you will get a higher background electrical noise level when you turn up the record gain on the recorder, you'll get the best signal-to-noise ratio. If you don't have a good enough s/n ratio, that means you don't have enough signal and you need to get closer to the source. You should recognize that the SPL generated by the things you're wanting to record is really not very great unless you're talking about a passing fire engine with the siren blaring (which can often exceed 100 dB SPL) so you're simply not going to be able to bring them too far above ambient noise. It's what's there. If there's no fixed answer to this, is there an experiment that I can do that would allow me to find the answer? Sure. Record some of the kinds of sound that you want to capture with the gain set at maximum (or as high as you can get it before you reach clipping) and then back the gain off by 10 or 20 dB. Import the recordings into your computer audio program, add gain to the sections where you lowered the gain, then listen to the playback. Pick what you like the most. I don't know if there's a way to "record silence" with built-in microphones, though. Wrap it in a blanket and put it in a quiet room. It's not perfect but it'll let you listen to how much the noise increases when you turn up the gain. You can do a similar experiment this way to recording what you're trying to record but with essentially no signal. But you'll probably need to add more gain to all of the test recordings of "silence" in order to clearly hear the difference. For example, if you record at maximum gain, 10 dB, and 20 dB lower, you'll probably want to add 60 dB to the lowest gain recording, 50 dB to the next lowest, and 40 dB to the highest gain setting. That should give you something loud enough to hear the differences. -- "Today's production equipment is IT based and cannot be operated without a passing knowledge of computing, although it seems that it can be operated without a passing knowledge of audio." - John Watkinson http://mikeriversaudio.wordpress.com - useful and interesting audio stuff |
#9
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On 3/23/2012 6:21 AM, Mxsmanic wrote:
Which will produce less noise in the finished recording? Or will the amount of noise in the finished product be the same either way? Normalization is nothing more than adding gain. The thing is that the process, rather than you , decides how much gain to add in order to get to the level that you set as the target (if it's not automatically full scale). It's mainly a concern for very quiet environments, such as inside a park. For other street noise, the sound levels are so high that any noise from the equipment is irrelevant. Either way, you'll be amplifying everything so the ratio between the hummingbird flitting around the rose bush in the park and the lawn mower on the other side of the street will be unchanged. If you want the humming bird to speak up, you'll need to get closer to the bird and further from the lawn mower. -- "Today's production equipment is IT based and cannot be operated without a passing knowledge of computing, although it seems that it can be operated without a passing knowledge of audio." - John Watkinson http://mikeriversaudio.wordpress.com - useful and interesting audio stuff |
#10
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![]() "Mxsmanic" wrote in message ... Is it better to increase the gain on my Zoom in situations where sound levels are low, or should I leave the gain lower and then normalize the recording later on? Normalization is a very blunt stick. It works where indicated, but has broad effects otherwise. Plan B: Increase the level by adding thought-out number of dB worth of gain. Which produces less noise in the end result? Or do they both amount to the same thing? Sounds levels low, covers an impossibly large range to give just one answer to. If your actual peak levels are 16 or more DB down, then increase the gain of the Zoom while recording until they are more like 10 dB down. Adjust the gain of your recordings to suit during production, prior to distribution. |
#11
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On Fri, 23 Mar 2012 07:35:02 -0400 "Mike Rivers"
wrote in article .... I don't know if there's a way to "record silence" with built-in microphones, though. Wrap it in a blanket and put it in a quiet room. It's not perfect but it'll let you listen to how much the noise increases when you turn up the gain. I use an H4n a lot for recording chamber ensembles (but with external mics). I did the wrap-it-a-blanket test when I bought the H4n (external mics sharing the blanket). I even wrote down the results, which I can now no longer find, but IIRC noise didn't go up much until gain was set close to maximum, and even then the increase wasn't large. I haven't tried substituting resistors for the mics; that might be interesting. I tried something else. Audition has an Amplitude Statistics function. It finds, among other things, the largest and smallest samples in the file and calculates the dynamic range. For the recordings I typically make, usually in venues that are not particularly quiet, it reports dynamic range of 50-60dB. I set the recording level to peak around -20dB and have never seen clipping except for the applause (limiting and low-cut filter are off). The lowest-amplitude parts are still dominated by ambient room noise. The wrapped-in-a-blanket test, with input gain set to where I usually have it for live recording, yields dynamic range of about 60- 65dB. Now I'm going to try the same thing with the gain all the way up. |
#12
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"Mxsmanic" wrote in message
... Luxey writes: Increase gain, so that highest peaks are as close to zero as possible, but not cliping. So you have to make voluntary sfety margin, as small as you think will be enough. OK. So in a very quiet environment, it's better to crank the gain than to set it lower and normalize later on. Be VERY careful about how close you get to zero - the meters are probably not as accurate as you think. Setting the gains a little too low can be adjusted in post. Setting them a little high can not. Sean |
#13
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Mxsmanic wrote:
Peter Larsen writes: I don't know what Zoom device you have. I don't know what microphone(s) you have. I don't know which external pre you are using. I don't know what you are recording. H4n, with its built-in microphones. Nothing external. Mostly city noises, like traffic, or sounds in a park or on a bridge, etc. For cityscapes I'd find a set and forget setting, ie. I'd boost in post as long as things sound OK. We have come a long way from the 12 and 13 bit recorders, I recall recording alternative jazzical with my SV3800 and noting that I had a wordlenght problem because the spoken, unamplified introductions sounded robotic. I would even then weigh proper loudness scaling to be more important than ultra-fi considerations. A storyteller - on my suggestion - bought a H2 and went recording old folks telling their life stories with the gain set in the niddle of its three positions, ie. underrecorded so that it peaked -32 dB. Fixed the obvious (based on FFT analysis) response dips that came from placing it on a table and normalized and she - and the libraries that paid the recordings - was happy, it good quite good. If there's no fixed answer to this, is there an experiment that I can do that would allow me to find the answer? For example, with digital cameras, you can take a picture of darkness (lens covered) and then pull the result into Photoshop and force the pixel values to span their full scale, producing a visible pattern of weak pixels, if any. I don't know if there's a way to "record silence" with built-in microphones, though. You have two factors to consider here. One being the wordlength you need, Arny used to have some examples of how short a wordlength you could get away with on his abx site as I recall it. The other being that analog electronics tend to sound cleanest if put a reasonable amount of signal through them. To render cityscapes for playback you quite possibly need to learn to use a multiband compressor, the one from izotope that comes with Audition 2/3 is to my liking, but you need to learn to use it. You can get it from izotope if you're using another audio software package and there are no doubt multiple other competing products. Remember: some of the time you have to artificialize gravely for things to sound natural. Summary: normalize may be the better strategy, possibly better still: put it through a multiband compressor and normalize afterwards. Kind regards Peter Larsen |
#14
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On 3/23/2012 9:52 PM, Jason wrote:
The wrapped-in-a-blanket test, with input gain set to where I usually have it for live recording, yields dynamic range of about 60- 65dB. That's about what you can expect from a good analog tape deck without noise reduction. No wonder that recording system worked so well for so many years. ![]() -- "Today's production equipment is IT based and cannot be operated without a passing knowledge of computing, although it seems that it can be operated without a passing knowledge of audio." - John Watkinson http://mikeriversaudio.wordpress.com - useful and interesting audio stuff |
#15
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Peter Larsen writes:
The other being that analog electronics tend to sound cleanest if put a reasonable amount of signal through them. I'm not sure I understand this. If I put a high level of sound through a recorder with the gain set to something intermediate, does that produce more noise than a low level of sound with a high gain setting, or what? From what I've read I've understood that the greater the gain in any type of amplifier, the more noise and/or distortion it will introduce into the amplified signal (more than a linear increase). Is that true, or do I have it wrong? It's not a huge issue for me, but I'd like to know how to set the gain on my H4n in order to minimize noise, even though I suspect that its noise floor is probably very low to begin with, for my purposes. To render cityscapes for playback you quite possibly need to learn to use a multiband compressor, the one from izotope that comes with Audition 2/3 is to my liking, but you need to learn to use it. You can get it from izotope if you're using another audio software package and there are no doubt multiple other competing products. Remember: some of the time you have to artificialize gravely for things to sound natural. I'm still trying to figure out how to compression and when to know that it's needed. I have no funds for payware plug-ins but there are some included plug-ins with Sound Forge (I have Audacity and the OEM version of Sound Forge that comes with Sony Vegas MS Platinum). Summary: normalize may be the better strategy, possibly better still: put it through a multiband compressor and normalize afterwards. OK, I'll do some experiments with that. Often the biggest problem I have with normalization is that there's something in the recording that happens to go near 0 dB, and so the normalization changes almost nothing. |
#16
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Sean Conolly writes:
Be VERY careful about how close you get to zero - the meters are probably not as accurate as you think. Setting the gains a little too low can be adjusted in post. Setting them a little high can not. The sources I'm recording (traffic noises and other urban noise) tend to be highly unpredictable, and often I end up recording with the meter hovering around -12 dB or even -20 dB just to avoid clipping when the occasional car horn honks or a motor scooter goes by. One things that surprises me is that the sounds that I would expect to see hitting 0 dB often do not, whereas the sounds that I would not expect to see clipped are in fact being clipped. For example, car horns don't seem to be as loud as they sound to my ears, but sometimes the rumble of a passing bus actually reaches 0 dB even though it doesn't seem that loud. |
#17
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From what I've read I've understood that the greater the gain in any
type of amplifier, the more noise and/or distortion it will introduce into the amplified signal (more than a linear increase). Is that true, or do I have it wrong? Broadly speaking, wrong, because you're saying "any". That's like saying "any" car with a 200hp engine will necessarily have poorer gas mileage than "any" car with a 150hp engine. Given a specific design... If the amplifier's gain is set with feedback, then higher gain will result in higher noise and distortion. If an amplifier has fixed gain, and the "system" gain is set with a pot, then the absolute noise level and distortion will not be affected by the gain. |
#18
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On Mar 24, 8:22*am, Mxsmanic wrote:
One things that surprises me is that the sounds that I would expect to see hitting 0 dB often do not, whereas the sounds that I would not expect to see clipped are in fact being clipped. For example, car horns don't seem to be as loud as they sound to my ears, but sometimes the rumble of a passing bus actually reaches 0 dB even though it doesn't seem that loud. Google "Fletcher-Munson" for an explanation. Peace, Paul |
#19
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On 3/24/2012 9:18 AM, Mxsmanic wrote:
It's not a huge issue for me, but I'd like to know how to set the gain on my H4n in order to minimize noise, even though I suspect that its noise floor is probably very low to begin with, for my purposes. Well, you really don't have much choice since there's only one place to set record level, which appears to adjust the gain or attenuation of the input stage. So the same old analog principle applies - for the best signal-to-noise ratio, get as much gain as you can from the earliest stage amplifying the source. But the difference in signal-to-noise ratio between having the digial record level hitting 0 dBFS all the time (and hopefully not going over) and running it 10 dB lower is really insignificant in the practical sense. Running at a little lower level keeps you safer from digital clipping and maybe the converters are a little more linear a bit down from the end of the scale. But running it so that the level never exceeds -40 dBFS is probably going to make the noise of the converters start to come up if you amplify it after the fact. Often the biggest problem I have with normalization is that there's something in the recording that happens to go near 0 dB, and so the normalization changes almost nothing. If it's a brief sound that you can reduce the level of without affecting the program material, then do that first, and then normalize. If there's a car crash in the midst of a bird song, you can just reduce the level of the car crash and then bring up the level of the whole file by normalizing. But if the song gets 10 dB louder in parts, it's probably supposed to be that way. I never consider normalization to be a "mastering process" but rather a shortcut to bring up the overall level of a recording that has a normal amount of dynamic range but just an overall low level. You can look at the waveform envelope and see where something sticks up way above the eyeball average of the material, listen to that, and decide if you can, or should, knock it down, or if it needs to be there, and it's at the right level relative to everything else. This is all stuff that you can do with your digital editing tools that's much more difficult to do with analog tools, so it's easy to get tempted to spend way too much time with it. But the results might be worth it. -- "Today's production equipment is IT based and cannot be operated without a passing knowledge of computing, although it seems that it can be operated without a passing knowledge of audio." - John Watkinson http://mikeriversaudio.wordpress.com - useful and interesting audio stuff |
#20
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On 3/24/2012 9:22 AM, Mxsmanic wrote:
The sources I'm recording (traffic noises and other urban noise) tend to be highly unpredictable, and often I end up recording with the meter hovering around -12 dB or even -20 dB just to avoid clipping when the occasional car horn honks or a motor scooter goes by. There's nothing at all wrong with that. But consider this - do you want the background noise, or is that car horn or motor scooter really important and something that you want to save? If it is, then you either need to allow for it, or engage a limiter to sit on those unexpected sounds that are much higher than your background level if it sounds OK. If you don't care about those random loud sounds, let 'em clip and just edit them out. The TASCAM DR-40, and maybe you can do the same trick with other recorders that can record 4 tracks, lets you set up a second pair of tracks recording at a lower level than your primary set. If something overloads on your primary tracks, chances are it'll be OK on the tracks with lower gain, and you can edit between the two sets of tracks. The Sony PCM-D50's limiter actually works like this automatically. It records a buffer 10 or 20 dB below the main track. When it detects an overload, it automatically replaces the overloaded section with the backup and then normalizes the spliced-in segment so it will go to full scale. It's really cool. One things that surprises me is that the sounds that I would expect to see hitting 0 dB often do not, whereas the sounds that I would not expect to see clipped are in fact being clipped. For example, car horns don't seem to be as loud as they sound to my ears, but sometimes the rumble of a passing bus actually reaches 0 dB even though it doesn't seem that loud. That's because a car horn is a designed sound. It's supposed to be easy to hear, which means that it sounds louder than it actually is, though I've measured passing fire engines at 100 dB SPL when their sirens are going. A bus has a lot of low frequency energy that moves a lot of air, but your ear is less sensitive than an A/D converter in that frequency range. -- "Today's production equipment is IT based and cannot be operated without a passing knowledge of computing, although it seems that it can be operated without a passing knowledge of audio." - John Watkinson http://mikeriversaudio.wordpress.com - useful and interesting audio stuff |
#21
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On Thu, 22 Mar 2012 22:42:33 -0700, Mxsmanic wrote
(in article ): Is it better to increase the gain on my Zoom in situations where sound levels are low, or should I leave the gain lower and then normalize the recording later on? Which produces less noise in the end result? Or do they both amount to the same thing? ------------------------------snip------------------------------ See: gain staging. http://www.emusician.com/news/0766/max-headroom/147106 --MFW |
#22
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Mxsmanic wrote:
Peter Larsen writes: The other being that analog electronics tend to sound cleanest if put a reasonable amount of signal through them. I'm not sure I understand this. Read it aloud to yourself then, I mean exactly what I write. A couple of IC opamp generations ago I used LF356's in my electronic x-over. When I moved to this apartment I suddenly got neighbor complaints due to lower outside background noise. To make it easier for myself to accomodate those I decided to attenuate all power-amplifiers on the input and ended up with 15 dB attenuation. Result: cleaner sound because the x-over ran 15 dB hotter. If I put a high level of sound through a recorder with the gain set to something intermediate, does that produce more noise than a low level of sound with a high gain setting, or what? You ask how it measures when I say how it sounds. From what I've read I've understood that the greater the gain in any type of amplifier, the more noise and/or distortion it will introduce into the amplified signal (more than a linear increase). Is that true, or do I have it wrong? I think you're closer to having it wrong than right in as much as it is just not that simple. Remove the any as William suggested and it gets less wrong. An example: The Fostex MR8HD is amazingly clean at its price point if you feed it a line signal, but the higher the gain setting the grainier it gets. It doesn't get "bad", just less clean, more "plasticky" sound on violins and vox, just a bit. I have made recordings of storytelling on mine using it near max gain, and used it for a vox improvisation that led to a great "hook" yestersay totally maxed because I grabbed a SM7 and it sounds great. It's not a huge issue for me, but I'd like to know how to set the gain on my H4n in order to minimize noise, even though I suspect that its noise floor is probably very low to begin with, for my purposes. You set it so that the signal doesn't clip, except when/if as Mike suggested you don't mind discarding clipped signal. When recording cityscapes - and now it gets to be an artistic opinon rather than a techie opinion - I'd want the fire engine and the diesel 18-wheeler recorded cleanly to preserve the contrast. The result will be as unplayable as a fireworks recording or a recording of avant garde jazzical, to get it playable you need to learn how to scale it. I think Mike's suggestion of recording a second pair of tracks 20 dB lower is a good one. Parallel compression is another ploy, I think it is a british invention, but it is so obvius once it is understood and so simple that many people may have come up with it. Split the signal, put it through a compresser with gentle settings and a low treshold and add it to the signal. The outcome will be that transients are mostly uncompressed but the low levels are brought up and overall the compression rate gets about half what the compressor is set at. With Audition I have done it differently and just drawn a suitable compressor transfer characteristic and never checked whether truly modelling parallel compression would be better, perhaps with the multiband. I'm still trying to figure out how to compression and when to know that it's needed. I have no funds for payware plug-ins but there are some included plug-ins with Sound Forge (I have Audacity and the OEM version of Sound Forge that comes with Sony Vegas MS Platinum). There's a good three band in Magix "home studio" and the package ought to be in the USD 50 to 79.95 range. It is however somewhat dumbified, and thus a bit difficult to ensure that you're in 32 bit file format, I bought it some years ago and ended up not at all using it. Often the biggest problem I have with normalization is that there's something in the recording that happens to go near 0 dB, and so the normalization changes almost nothing. That is not a problem, that is what it is. Anyway, it is, in the context of making stuff sound similarly loud, useless anyway. Average level with a 300 millesecond time window as calculated by Auditions statistics window works well for me. Auditions automated average level alignment for some reason doesn't, especially not if allow to assume fletcher munson valid as a part of the calculation, but also not anyway. Listening has been suggested as a usable strategy, but nobody does that any more. Kind regards Peter Larsen |
#23
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Mike Rivers writes:
If it's a brief sound that you can reduce the level of without affecting the program material, then do that first, and then normalize. I haven't been able to figure out which function (in Sound Forge or Audacity) does that. I can amplify a section of the recording, but there's no smoothing of the edges or anything, so the entire recording suddenly becomes software ore louder for a brief period, and this is easily audible and sounds artificial. Is there a standard function of some kind in sound-editing software that does this a little more smoothly? Often I resort to just deleting the loud sound. This seems to be less noticeable than trying to change its intensity, even though it would sometimes be nice to keep it. I never consider normalization to be a "mastering process" but rather a shortcut to bring up the overall level of a recording that has a normal amount of dynamic range but just an overall low level. For unpredictable sources I leave lots of headroom, but that compels me to normalize later on if I want the recording to be at a "standard" level--otherwise presumably someone else using it would have to normalize, anyway. Maybe I just need to find things to record that are more predictable. Believe it or not, I haven't recorded any music with the H4n so far, although I have recorded voice narration (with excellent results). Music raises the spectre of copyright, which severely limits my ability to share anything that I record. You can look at the waveform envelope and see where something sticks up way above the eyeball average of the material, listen to that, and decide if you can, or should, knock it down, or if it needs to be there, and it's at the right level relative to everything else. But if it's something like, say, a pop or bang on the recording, I haven't figured out how to crank down that single sound without reducing the audio levels nearby. This is all stuff that you can do with your digital editing tools that's much more difficult to do with analog tools, so it's easy to get tempted to spend way too much time with it. But the results might be worth it. Is there a specific tool I should look for that is particularly adapted to reducing the intensity of loud, brief sounds in a recording? |
#24
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Mike Rivers writes:
There's nothing at all wrong with that. But consider this - do you want the background noise, or is that car horn or motor scooter really important and something that you want to save? If it is, then you either need to allow for it, or engage a limiter to sit on those unexpected sounds that are much higher than your background level if it sounds OK. If you don't care about those random loud sounds, let 'em clip and just edit them out. Yes, I see your point. The H4n has a built-in compressor and limiter, and some auto-level controls, but I haven't used them thus far on the theory that I should not tinker with the original recording any more than absolutely necessary, since changes made during recording (as opposed to during editing) cannot be backed out. (This is a philosophy I have followed with video for ages.) The TASCAM DR-40, and maybe you can do the same trick with other recorders that can record 4 tracks, lets you set up a second pair of tracks recording at a lower level than your primary set. If something overloads on your primary tracks, chances are it'll be OK on the tracks with lower gain, and you can edit between the two sets of tracks. I can't find this on the H4n, unless I don't know what to look for. There's some sort of adjustment for "mid/side" recording, but I haven't figured out what it does. The Sony PCM-D50's limiter actually works like this automatically. It records a buffer 10 or 20 dB below the main track. When it detects an overload, it automatically replaces the overloaded section with the backup and then normalizes the spliced-in segment so it will go to full scale. It's really cool. Doesn't sound like I have that, but the H4n has all sorts of nifty functions so I could be missing something. That's because a car horn is a designed sound. It's supposed to be easy to hear, which means that it sounds louder than it actually is, though I've measured passing fire engines at 100 dB SPL when their sirens are going. A bus has a lot of low frequency energy that moves a lot of air, but your ear is less sensitive than an A/D converter in that frequency range. That makes sense. I might be unusually sensitive to low frequencies because sometimes I hear booming low frequencies that don't seem to bother anyone else, particularly from vehicles. I guess their mufflers are designed to lower the frequency of noise rather than eliminate it. |
#25
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Marc Wielage writes:
See: gain staging. http://www.emusician.com/news/0766/max-headroom/147106 Thanks! |
#26
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Mxsmanic wrote:
Mike Rivers writes: If it's a brief sound that you can reduce the level of without affecting the program material, then do that first, and then normalize. I haven't been able to figure out which function (in Sound Forge or Audacity) does that. I can amplify a section of the recording, but there's no smoothing of the edges or anything, so the entire recording suddenly becomes software ore louder for a brief period, and this is easily audible and sounds artificial. Is there a standard function of some kind in sound-editing software that does this a little more smoothly? Often I resort to just deleting the loud sound. This seems to be less noticeable than trying to change its intensity, even though it would sometimes be nice to keep it. I never consider normalization to be a "mastering process" but rather a shortcut to bring up the overall level of a recording that has a normal amount of dynamic range but just an overall low level. For unpredictable sources I leave lots of headroom, but that compels me to normalize later on if I want the recording to be at a "standard" level--otherwise presumably someone else using it would have to normalize, anyway. Maybe I just need to find things to record that are more predictable. Believe it or not, I haven't recorded any music with the H4n so far, although I have recorded voice narration (with excellent results). Music raises the spectre of copyright, which severely limits my ability to share anything that I record. You can look at the waveform envelope and see where something sticks up way above the eyeball average of the material, listen to that, and decide if you can, or should, knock it down, or if it needs to be there, and it's at the right level relative to everything else. But if it's something like, say, a pop or bang on the recording, I haven't figured out how to crank down that single sound without reducing the audio levels nearby. This is all stuff that you can do with your digital editing tools that's much more difficult to do with analog tools, so it's easy to get tempted to spend way too much time with it. But the results might be worth it. Is there a specific tool I should look for that is particularly adapted to reducing the intensity of loud, brief sounds in a recording? Volume automation lets you draw an envelope to control the channel gain. It's available in all the audio editing programs I've ever used since CoolEdit 96. Or use a limiter plugin and turn the channel gain up, letting the limiter automatically reduce the gain on the loud bits. When you do it digitally, you can redo it as often as you like on copies using different settings without generational losses or damaging the original file. -- Tciao for Now! John. |
#27
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On 3/25/2012 3:30 AM, Mxsmanic wrote:
If it's a brief sound that you can reduce the level of without affecting the program material, then do that first, and then normalize. I haven't been able to figure out which function (in Sound Forge or Audacity) does that. I don't know about Audacity but in Sound Forge, just select the part that's too loud by dragging the cursor across it (it will be highlighted), then click on Process, then click Volume in the Process menu, and adjust the slider. If you don't highlight a region in the track, it will process the whole recording. If you highlight a region, it will process only the highlighted region. I can amplify a section of the recording, but there's no smoothing of the edges or anything, so the entire recording suddenly becomes software ore louder for a brief period, and this is easily audible and sounds artificial. Well, it IS artificial. You can use Fade In and Fade Out to make the transitions gentler, and zooming in on the area where you want to work will help you find the best place to make the changes. This is an editing process and it's a craft. You need to practice. Is there a standard function of some kind in sound-editing software that does this a little more smoothly? Yeah, it's called pay a professional if you don't want to learn the techniques yourself. ![]() For unpredictable sources I leave lots of headroom, but that compels me to normalize later on if I want the recording to be at a "standard" level--otherwise presumably someone else using it would have to normalize, anyway. There's nothing wrong with normalizing as long as you understand what you're doing. Someone else using your recording would in his own production would probably have to adjust the level anyway. Maybe I just need to find things to record that are more predictable. That's the chicken way. Better to learn how to deal with what you find in the field. You never know what you might discover. Is there a specific tool I should look for that is particularly adapted to reducing the intensity of loud, brief sounds in a recording? Volume adjustment or volume envelope. With a volume envelope, you can draw a curve that represents the action of a volume control, that that's really more useful when the volume of an extended section (a couple of seconds or more) or a single word needs to be adjusted. -- "Today's production equipment is IT based and cannot be operated without a passing knowledge of computing, although it seems that it can be operated without a passing knowledge of audio." - John Watkinson http://mikeriversaudio.wordpress.com - useful and interesting audio stuff |
#28
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On 3/25/2012 3:44 AM, Mxsmanic wrote:
The H4n has a built-in compressor and limiter, and some auto-level controls, but I haven't used them thus far on the theory that I should not tinker with the original recording any more than absolutely necessary, since changes made during recording (as opposed to during editing) cannot be backed out. (This is a philosophy I have followed with video for ages.) That's a good philosophy as far as it goes, but sometimes a limiter or compressor can do what you would be doing afterward anyway. Your real problem here as I see it is simply lack of experience in doing this type of recording. You're going to spoil some before you get the hang of it. The more you do, the better your judgment will be. One thing that's nearly always bad is an automatic volume control, but a limiter or a compressor if set correctly can be helpful. The problem is that when recording sounds like you're doing, you really don't have an opportunity to adjust the compressor based on the sound because it's only there once and it's gone. There's some sort of adjustment for "mid/side" recording, but I haven't figured out what it does. That has to do with how the microphones "hear" stereo. Doesn't sound like I have that, but the H4n has all sorts of nifty functions so I could be missing something. Read the manual and start experimenting to see what they do. -- "Today's production equipment is IT based and cannot be operated without a passing knowledge of computing, although it seems that it can be operated without a passing knowledge of audio." - John Watkinson http://mikeriversaudio.wordpress.com - useful and interesting audio stuff |
#29
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On Saturday, 24 March 2012 14:18:11 UTC+1, Mxsmanic wrote:
I'm not sure I understand this. If I put a high level of sound through a recorder with the gain set to something intermediate, does that produce more noise than a low level of sound with a high gain setting, or what? More gain = more noise in absolute levels. However, proportionaaly, if you take a look at EIN numbers, you'll see the least noise is added at the highest gain. To simplify, by adding Xdb of gain, you're adding less than Xdb of noise. This is about the noise of preamp, not some background noise. |
#30
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On Sun 2012-Mar-25 07:25, Mike Rivers writes:
On 3/25/2012 3:30 AM, Mxsmanic wrote: If it's a brief sound that you can reduce the level of without affecting the program material, then do that first, and then normalize. I haven't been able to figure out which function (in Sound Forge or Audacity) does that. I don't know about Audacity but in Sound Forge, just select the part that's too loud by dragging the cursor across it (it will be highlighted), then click on Process, then click Volume in the Process menu, and adjust the slider. If you don't highlight a region in the track, it will process the whole recording. If you highlight a region, it will process only the highlighted region. Every daw I've ever been around has the ability to do something similar, they may call it different things, but that's where a daw has older analog methods beat hands down. I can amplify a section of the recording, but there's no smoothing of the edges or anything, so the entire recording suddenly becomes software ore louder for a brief period, and this is easily audible and sounds artificial. Well, it IS artificial. You can use Fade In and Fade Out to make the transitions gentler, and zooming in on the area where you want to work will help you find the best place to make the changes. This is an editing process and it's a craft. You need to practice. Yep, practice is how you learn, listen to your results. Save the file under a different name if your daw doesn't have 'undo" so that you can grab the unprocessed file and do it again after discarding the one you didn't like. Adjusting volume envelopes adn the like is what sold the daw revolution. Is there a standard function of some kind in sound-editing software that does this a little more smoothly? Yeah, it's called pay a professional if you don't want to learn the techniques yourself. ![]() That's right, but they're easy enough to learn. practice, and practice some more. You'll get better over time with it. DOn't like the changes? Don't save your work, do it again. This is why it's call nondestructive editing. There's nothing wrong with normalizing as long as you understand what you're doing. Someone else using your recording would in his own production would probably have to adjust the level anyway. This is true. Maybe I just need to find things to record that are more predictable. That's the chicken way. Better to learn how to deal with what you find in the field. You never know what you might discover. Indeed, adn all the tools you need are at your disposal with most of today's audio editing software. YOu just need to take some time to get familiar with the tools, how they work and what they can do for you. Undo is your friend. YOu have tools at your disposal that the audio editor of half a century ago could only dream of, it's a matter of learing to use them effectively, which can't be taught, or gleaned from reading newsgroup posts. Skills here are developed by using them, and listening to your results. "Today's production equipment is IT based and cannot be operated without a passing knowledge of computing, although it seems that it can be operated without a passing knowledge of audio." - John Watkinson YEp, and here we have the proof of that statement. IN this case though, the man might actually want to learn. IF so, the only way to do it is to jump in and do it. Regards, Richard -- | Remove .my.foot for email | via Waldo's Place USA Fidonet-Internet Gateway Site | Standard disclaimer: The views of this user are strictly his own. |
#31
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![]() "Mxsmanic" wrote in message ... Peter Larsen writes: The other being that analog electronics tend to sound cleanest if put a reasonable amount of signal through them. I'm not sure I understand this. If I put a high level of sound through a recorder with the gain set to something intermediate, does that produce more noise than a low level of sound with a high gain setting, or what? Usually the only effect is that a fixed amount of noise that is generated near the input is amplified by the gain of the amplifier. More gain, more noise in the recording. From what I've read I've understood that the greater the gain in any type of amplifier, the more noise and/or distortion it will introduce into the amplified signal (more than a linear increase). Is that true, or do I have it wrong? For a given amplifier that may be true. Obviously, higher gain amplifiers may be biilt with lower distortion by using more advanced technology, or more of it. Consider an amplifier with an active element that provides a fixed amount of gain. Gain is set by an attenuator at its input, before any active circuitry. It's distortion is unaffected by the gain setting, but it is affected by the size of the output signal. The two strong sources of distortion in an amplifier are output voltage and gain. It's not a huge issue for me, but I'd like to know how to set the gain on my H4n in order to minimize noise, even though I suspect that its noise floor is probably very low to begin with, for my purposes. Experiment. You can measure how much noise it makes by analyzing its recordings. Record with loud signals, soft signals and no signal/ Record with low, medium and high gain. Mix and match. What do you find? To render cityscapes for playback you quite possibly need to learn to use a multiband compressor, the one from izotope that comes with Audition 2/3 is to my liking, but you need to learn to use it. You can get it from izotope if you're using another audio software package and there are no doubt multiple other competing products. Remember: some of the time you have to artificialize gravely for things to sound natural. I'm still trying to figure out how to compression and when to know that it's needed. I have no funds for payware plug-ins but there are some included plug-ins with Sound Forge (I have Audacity and the OEM version of Sound Forge that comes with Sony Vegas MS Platinum). There are ton of freeware VST plugins. Often the biggest problem I have with normalization is that there's something in the recording that happens to go near 0 dB, and so the normalization changes almost nothing. Often the peaks are extremely short term (a few milliseconds) and lowering just them will have minimal effects on the overall sound quality. My DAW r has tools for lowering them. Does yours? |
#32
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![]() "Mxsmanic" wrote in message ... Sean Conolly writes: Be VERY careful about how close you get to zero - the meters are probably not as accurate as you think. Setting the gains a little too low can be adjusted in post. Setting them a little high can not. The sources I'm recording (traffic noises and other urban noise) tend to be highly unpredictable, and often I end up recording with the meter hovering around -12 dB or even -20 dB just to avoid clipping when the occasional car horn honks or a motor scooter goes by. Don't worry about that. One things that surprises me is that the sounds that I would expect to see hitting 0 dB often do not, whereas the sounds that I would not expect to see clipped are in fact being clipped. For example, car horns don't seem to be as loud as they sound to my ears, That's because they are designed to be heard, despite minimal energy use. Their tones are full of frequencies where your ear is most sensitive. but sometimes the rumble of a passing bus actually reaches 0 dB even though it doesn't seem that loud. That's because your ears are relatively insensitive at low frequencies. |
#33
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Arny Krueger writes:
That's because they are designed to be heard, despite minimal energy use. Their tones are full of frequencies where your ear is most sensitive. That makes sense. (Yes, I'm familiar with the Fletcher-Munson curves, it just hadn't occurred to me.) but sometimes the rumble of a passing bus actually reaches 0 dB even though it doesn't seem that loud. That's because your ears are relatively insensitive at low frequencies. Which I suppose is the reason for mufflers shifting the frequency of exhaust sounds. I note that in my bathroom (which has a frosted window facing the street), I sometimes hear booming low-frequency noise when there's a bus idling at the traffic light outside (about 50 meters away). If I step outside the bathroom (which is quite small), the booming mostly stops, but inside the bathroom it is very loud. There must be some weird interaction between the acoustics of the small bathroom and the exhaust noises of the bus. And it seems to be a very low sound, so much so that it makes my ears feel "puffy" as it rumbles. I haven't had a chance to rush into the bathroom with my recorder yet to see how the sound looks objectively, but someday I will. |
#34
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Mxsmanic wrote:
Arny Krueger writes: That's because they are designed to be heard, despite minimal energy use. Their tones are full of frequencies where your ear is most sensitive. That makes sense. (Yes, I'm familiar with the Fletcher-Munson curves, it just hadn't occurred to me.) but sometimes the rumble of a passing bus actually reaches 0 dB even though it doesn't seem that loud. That's because your ears are relatively insensitive at low frequencies. Which I suppose is the reason for mufflers shifting the frequency of exhaust sounds. They don't actually shift the frequencies, they just work as a low pass filter. There is also sound made by some engine blocks when they flex under the combustion chamber pressures, and some resonances in the bodywork which are excited by the engine and transmission noise. I note that in my bathroom (which has a frosted window facing the street), I sometimes hear booming low-frequency noise when there's a bus idling at the traffic light outside (about 50 meters away). If I step outside the bathroom (which is quite small), the booming mostly stops, but inside the bathroom it is very loud. There must be some weird interaction between the acoustics of the small bathroom and the exhaust noises of the bus. And it seems to be a very low sound, so much so that it makes my ears feel "puffy" as it rumbles. I haven't had a chance to rush into the bathroom with my recorder yet to see how the sound looks objectively, but someday I will. Most bus and lorry engines idle at 650 or 700 RPM, which give a fundamental exhaust note of about 33 - 35 Hz. If you enter your bathroom dimensions into this:- http://www.mcsquared.com/metricmodes.htm You may well find a room mode at the second or third harmonic of the bus engine frequency. -- Tciao for Now! John. |
#35
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John Williamson writes:
Most bus and lorry engines idle at 650 or 700 RPM, which give a fundamental exhaust note of about 33 - 35 Hz. If you enter your bathroom dimensions into this:- http://www.mcsquared.com/metricmodes.htm You may well find a room mode at the second or third harmonic of the bus engine frequency. I plugged in the room dimensions (W 1.6 x L 1.8 x H 3.0 meters), but I'm not sure what the output was telling me. |
#36
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Mxsmanic wrote:
John Williamson writes: Most bus and lorry engines idle at 650 or 700 RPM, which give a fundamental exhaust note of about 33 - 35 Hz. If you enter your bathroom dimensions into this:- http://www.mcsquared.com/metricmodes.htm You may well find a room mode at the second or third harmonic of the bus engine frequency. I plugged in the room dimensions (W 1.6 x L 1.8 x H 3.0 meters), but I'm not sure what the output was telling me. The lowest frequency mode is at 57.33 Hz, although you may get some excitation at half that, which is a bit low for most bus engines. -- Tciao for Now! John. |
#37
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On Tue, 27 Mar 2012 12:45:37 +0200, Mxsmanic
wrote: John Williamson writes: Most bus and lorry engines idle at 650 or 700 RPM, which give a fundamental exhaust note of about 33 - 35 Hz. If you enter your bathroom dimensions into this:- http://www.mcsquared.com/metricmodes.htm You may well find a room mode at the second or third harmonic of the bus engine frequency. I plugged in the room dimensions (W 1.6 x L 1.8 x H 3.0 meters), but I'm not sure what the output was telling me. The frequencies are those at which the effects of modes are greatest. If you play a tone at one of the frequencies, you will find that the volume changes enormously (from loud to inaudible in some cases) as you walk around the room. The idea of room treatment is to iron out those changes and leave the response as far as possible without the peaks and dips. A really good room treatment might reduce them to 10dB or so. The bus note in the bathroom is going to be close to one of those modal frequencies. Walk across or along the bathroom while it is happening, and you should be able to make the sound come and go. d |
#38
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Don Pearce writes:
The bus note in the bathroom is going to be close to one of those modal frequencies. Walk across or along the bathroom while it is happening, and you should be able to make the sound come and go. Hmm, I shall try that. |
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