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#1
Posted to rec.audio.tech
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Boosting low-level audio
I am in the process of editing a two-camera video of a semi-acoustic band
using Adobe Premiere 1.5, with audio separately recorded onto DAT. Mindful that television audio needs to be on some sort of constant plane of volume, my problem is that the DAT recording contains some very major highs and lows. If I put the audio on "as is" all the low-level parts (mainly where the singer is speaking to the audience) would be pretty much inaudible. What I would ideally like to do is boost the low level signal without even touching the higher volume stuff. I've tried compression but I'm finding it very difficult to find a point where I can clearly hear the spoken parts but which doesn't distort the louder more dynamic music (bass and drums particularly) very badly. To hear the speech at an acceptable level I would need to compress it (I'm using Sound Forge Wav Hammer) with a threshold somewhere between -30 and -35 dB and ratio at 3:1 to 4:1. What I want, I guess, is the opposite of compression... where instead of suppressing the high level I'd be bringing the lower level stuff up to meet it. Or maybe it's the same thing and I'm missing something! I'm seriously considering leaving the music as it is and applying compression to the spoken parts only, but I'm worried about sudden leaps in gain at these points. Can anyone assist me, please? |
#2
Posted to rec.audio.tech
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Boosting low-level audio
"P" wrote in message ... I am in the process of editing a two-camera video of a semi-acoustic band using Adobe Premiere 1.5, with audio separately recorded onto DAT. Mindful that television audio needs to be on some sort of constant plane of volume, my problem is that the DAT recording contains some very major highs and lows. If I put the audio on "as is" all the low-level parts (mainly where the singer is speaking to the audience) would be pretty much inaudible. What I would ideally like to do is boost the low level signal without even touching the higher volume stuff. I've tried compression but I'm finding it very difficult to find a point where I can clearly hear the spoken parts but which doesn't distort the louder more dynamic music (bass and drums particularly) very badly. To hear the speech at an acceptable level I would need to compress it (I'm using Sound Forge Wav Hammer) with a threshold somewhere between -30 and -35 dB and ratio at 3:1 to 4:1. What I want, I guess, is the opposite of compression... where instead of suppressing the high level I'd be bringing the lower level stuff up to meet it. Or maybe it's the same thing and I'm missing something! I'm seriously considering leaving the music as it is and applying compression to the spoken parts only, but I'm worried about sudden leaps in gain at these points. Can anyone assist me, please? feeding the audio through an Aphex Compellor or some device with similar ACG function may be your best bet. the Behringer Ultramizer may be a good alternative. if the end use is for broadcast you may not need to do anything at all. the processors at the transmitter will squish the audio just fine |
#3
Posted to rec.audio.tech
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Boosting low-level audio
feeding the audio through an Aphex Compellor or some device with similar
ACG function may be your best bet. the Behringer Ultramizer may be a good alternative. Thanks for the advice, however it's a not-for-sale venture and I won't be forking out any more on it than I already have, other than my time. if the end use is for broadcast you may not need to do anything at all. the processors at the transmitter will squish the audio just fine It's definitely not for broadcast - permission granted only to video and distribute to people who couldn't be there, or those who were and want to remember. The effect you're talking about would be ideal - a dynamic compression that adjusts according to input. I can't see anything within Sound Forge that would do that. |
#4
Posted to rec.audio.tech
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Boosting low-level audio
"P" wrote in message
I am in the process of editing a two-camera video of a semi-acoustic band using Adobe Premiere 1.5, with audio separately recorded onto DAT. Mindful that television audio needs to be on some sort of constant plane of volume, my problem is that the DAT recording contains some very major highs and lows. If I put the audio on "as is" all the low-level parts (mainly where the singer is speaking to the audience) would be pretty much inaudible. What I would ideally like to do is boost the low level signal without even touching the higher volume stuff. The best way to do this is to manually identify, select and adjust the volume of the various logical segments of the recording. What may not be obvious is that the subjective loudness of audio is not directly related to visible amplitude on the screen. You'll have to work out the necessary adustments by ear. This is easy enough to do in Audition, but over the span of a long recording it can involve some work. I never promised you a rose garden! ;-) More specifically, my tools of choice are Effects, Amplification and Effects, Envelope. One helpful tool is a collection of envelopes that start and end with unity (1.0) gain, and smoothly but rapdidly transition to the desired amount of gain or reduction, and then return. |
#5
Posted to rec.audio.tech
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Boosting low-level audio
"P" wrote in message ... feeding the audio through an Aphex Compellor or some device with similar ACG function may be your best bet. the Behringer Ultramizer may be a good alternative. Thanks for the advice, however it's a not-for-sale venture and I won't be forking out any more on it than I already have, other than my time. if the end use is for broadcast you may not need to do anything at all. the processors at the transmitter will squish the audio just fine It's definitely not for broadcast - permission granted only to video and distribute to people who couldn't be there, or those who were and want to remember. The effect you're talking about would be ideal - a dynamic compression that adjusts according to input. I can't see anything within Sound Forge that would do that. im not familiar with the workings of SF but you can set just about any type of compression/expansion in cool/edit/Audition or save the time and squish it in real time with an Ultrimizer (about $50 used) or an Ultradyne (also low cost). a Composer or many other types of comp/limiter should be usable for you task, just set the attack and release times to slow. |
#6
Posted to rec.audio.tech
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Boosting low-level audio
Thanks Arny, I will check out Audition.
In the meantime, I think I've finally got my head around Wave Hammer in Sound Forge. There are two parts to it - Compression and Volume Maximizer. The idea seems to be to lop off the level from the high peaks using the Volume Maximizer at a point with minimal distortion, then compress the result so that anything above a certain threshold is boosted according to a selected ratio. In preview mode the results have been OK but not perfect yet, and both the processes in Wave Hammer can be done simultaneously. The result has been a much fuller sound from the band, and audible speech in between songs. The trick is to find the point that minimises distortion and "compression fatigue" for the listener. But I think I'm on the right track now. |
#7
Posted to rec.audio.tech
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Boosting low-level audio
just set the attack and release times to slow.
Thanks, I've been doing this with the release time and the results have been much more distortion-free. Don't fully understand it! Why the attack time also? |
#8
Posted to rec.audio.tech
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Boosting low-level audio
"P" wrote in message
Thanks Arny, I will check out Audition. In the meantime, I think I've finally got my head around Wave Hammer in Sound Forge. There are two parts to it - Compression and Volume Maximizer. The idea seems to be to lop off the level from the high peaks using the Volume Maximizer at a point with minimal distortion, then compress the result so that anything above a certain threshold is boosted according to a selected ratio. In preview mode the results have been OK but not perfect yet, and both the processes in Wave Hammer can be done simultaneously. The result has been a much fuller sound from the band, and audible speech in between songs. The trick is to find the point that minimises distortion and "compression fatigue" for the listener. But I think I'm on the right track now. AFAIK Sound Forge has similar gain adjustment facilities as Audtion. Dynamic range adjustement by automatic means can't equal that which can be done by an intelligent operator. |
#9
Posted to rec.audio.tech
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Boosting low-level audio
Dynamic range adjustement by automatic means can't equal that which can be
done by an intelligent operator. I just hope I have the intelligence (and the ears) for the job. I think I do. |
#10
Posted to rec.audio.tech
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Boosting low-level audio
"P" wrote in message ... just set the attack and release times to slow. Thanks, I've been doing this with the release time and the results have been much more distortion-free. Don't fully understand it! Why the attack time also? a typical compressor can be used in multiple fashions: fast attack, fast release, high ratio, high threshold and it's a limiter. medium attack medium release, moderate ratio and it's a compressor. slow attack, slow release, medium to high ratio and low threshold and it's an AGC. in addition some units have a 'gate' setting that 'freezes' the compression level in place when audio falls below its threshold. this is useful to prevent 'pumping'. in other words having the AGC/compression audibly noticeable. from what i can gather you want an end result of audio where the listener/viewer can set a comfortable level and not be forced to make constant adjustments up and down. this calls for gated AGC action and some peak limiting (to tame clipping) personally i like the all in one solutions offered by the dbx quantum or Behringer Ultradyne. these do the AGC split the audio in separate bands and compress, recombine and limit. the process is sometimes called 'finalizing' the dbx DDP has a preset called 'finisher' that does a similar process (but not multiband) |
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