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Improving audio

Posted: Tue Nov 24, 2015 1:46 pm
by chzuck
I am running the latest Audacity version on XP. I have several mini cassette tapes that I made years ago and I have loaded then onto my computer using Audacity. Now I am trying to make improvements in the recordings. The tape has the normal tape background noise, low volume in general and some voices are lower than others due to their distance from the recorder. I did not have an external mic for my mini recorder I used for the roundtable discussion. I have tried using normalize, followed by noise reduction then used an external program to even out the low and high voices. All this has made some improvement. Are there other, better things I could try? Is there a preferred order in which to edit audio in Audacity? I am relatively new at this and would much appreciate suggestions from more seasoned users.

Re: Improving audio

Posted: Tue Nov 24, 2015 3:57 pm
by kozikowski
Pearlcorder? I am just now retiring mine.

There's no magic. You hit the steps we would use. Audacity 2.1.0 and on are much better at tape hiss than the earlier versions (post the numbers when you tell us about your system).
external program to even out the low and high voices.
Which is?

Amplify and Normalize are close cousins and all they do is turn the volume up and down. No processing. Each one offers different controls and depend on your goal.

Koz

Re: Improving audio

Posted: Tue Nov 24, 2015 5:42 pm
by DVDdoug
The only additional thing I'd suggest is equalization. (For experimenting, I usually recommend using the Graphic Equalizer mode rather than the Draw Curves mode.)

The sliders on the right are the high frequencies, and boosting the frequencies above about 4,000Hz will bring-up the "T" and "S" sounds which can help with intelligibility. But, boosting these frequencies will also bring-up the background hiss and any artifacts left-over from noise reduction.

Boosting the 150-300Hz range will bring-out "voice resonance". Reducing frequencies below 100Hz will reduce low-frequency noise.

Those are just approximate frequencies and every recording is different so you'll just have to play with the sliders to see if you can get any improvement.

After equalization (or anything that can affect the volume/level) it's a good idea to normalize (again, since you've done it already) before exporting. Normalizing (or using the Amplify effect at the default) will bring the peaks down to 0dB to prevent clipping when you export. (Or, it will bring the levels up to 0dB if they are lower than that.)

Re: Improving audio

Posted: Tue Nov 24, 2015 7:23 pm
by chzuck
kozikowski wrote:Pearlcorder? I am just now retiring mine.

There's no magic. You hit the steps we would use. Audacity 2.1.0 and on are much better at tape hiss than the earlier versions (post the numbers when you tell us about your system).
external program to even out the low and high voices.
Which is?

Amplify and Normalize are close cousins and all they do is turn the volume up and down. No processing. Each one offers different controls and depend on your goal.

Koz
Yes, Pearlcorder. I bought an external mic for it some time ago and when I went to use it I found it was no good. Of course it is out of warranty, so I may have to retire my hardly used Pearlcorder. I bought it in 2007 for recording all the history at the roundtable discussion and only later bought the mic realizing how much better the recording could have been. Only used the recorder briefly one other time. Shame.

I am using Audacity 2.1.1 and the audio leveling program I used was Levelator2

Re: Improving audio

Posted: Tue Nov 24, 2015 8:38 pm
by kozikowski
I'm wearing mine out. I use it's ability to vanish while in use (attached, scroll down).

I've also nearly never found a condition that it wouldn't record. If you put one in the middle of the table, I would have thought it would record any conference. I've made microphone assemblies that worked for this. Paint it black and it vanishes. I've had people not know what it was and pile papers on top of it.

"Tell you what, let's move these papers so Vancouver can hear us."

Image
Image

The modern sound recorders can handle many computer microphones, but I wonder if the early Pearlcorders wouldn't. My microphone powers itself with a little watch battery, but "computer microphones" need power coming up the wire from the recorder.

The only failures (past running out of tape) were putting the recorder next to a noisemaker or finding someone in love with background music. There's a reason that spy movies always turn on a loud radio in the room just before they announce the secret plans.

My replacement is an Olympus WS-823. It will record meetings and can be configured for entertainment recording and will deliver a high quality WAV sound file.

Koz

Re: Improving audio

Posted: Tue Nov 24, 2015 8:41 pm
by kozikowski
To be clear, I would put the recorder on the black board instead of the microphone.
Koz

Re: Improving audio

Posted: Tue Nov 24, 2015 9:10 pm
by kozikowski
The reason I'm going on about this is to get original recordings up to snuff. It can be nearly impossible to "rescue" bad recordings in post-production.

The kiss of death is a forum posting that uses the words: "help me clean up."

Koz

Re: Improving audio

Posted: Tue Nov 24, 2015 9:49 pm
by chzuck
I experimented today. I connected my PC mic and it seemed to record great. My ME12 mic mounts right on the recorder. I tried it and with it almost against my mouth I could very faintly hear my voice on playback. What mic are you showing in the photos?

Re: Improving audio

Posted: Tue Nov 24, 2015 10:12 pm
by kozikowski
I need to post when I get back to the house.
Koz

Re: Improving audio

Posted: Wed Nov 25, 2015 2:27 am
by kozikowski
Note the last sentence:

— Product Features —

Ideal for transcription
Increases transcription accuracy by reducing ambient noise
Simply plugs into digital voice recorders



My microphone is a Radio Shack 30-3013 tie-tack microphone.

http://www.amazon.com/RadioShack-33-301 ... B000TLX0A2

When Radio Shack was still breathing, they were $18. It's omnidirectional. Receives sound from all directions. It's a Radio Shack version of an existing Sound Company microphone (I don't remember who).

Before we go too far down this pathway, what problem are we solving?

Koz