static during playback

[leosmith]

My friend's daughter is recording a book for my friend and I in Thai. She is reading the book while recording her voice with audacity. She is using my friend's headset (H Global GH629). It is plugged directly into my MacBook, which uses OS X 10.5.5. The mic is not USB; it uses the round hole for mic in the laptop. She sits alone in a quiet room while she records, and the computer runs on its battery. The computer appears to be very quiet (no loud fan noise).

For the first 2 minutes of playback we always get loud static/buzz. After that we get moderate static/buzz. This is playback before saving. We eventually convert to MP3, and when we do there appears to be little change. We have had some success improving the sound quality with noise removal. After noise removal, the first 2 minutes still have an annoyingly loud static/buzz, while the rest of the recording is quite acceptable.

Three questions.
1) Can you suggest ways to prevent the static/buzz in the first place?
2) Can you suggest better editing techniques?
3) Can you suggest a way to get past the first 2 minute issue?

Thanks

[kozikowski]

<<<it uses the round hole for mic in the laptop.>>>

Are you plugged into the connector with the little circle and two black arrows icon? That's the MacBook high level Line-In. MacBooks don't have a Microphone-In like PCs do.

According to the specifications of the headset it produces -56dB sound level which is about a thousand times quieter than the MacBook is expecting. You are experiencing the normal noise of the MacBook competing with the super-quiet microphone. Like trying to understand somebody talking from the other side of a noisy subway train.

You have exactly the opposite problem of people trying to record a high quality, high-level sound performance on their PC. They get horrible, loud distortion.

One cheap way out of this is to buy a different microphone. I use the Logitech USB Desktop Microphone on my PowerBook (which has the same sound connections you do).

http://www.logitech.com/index.cfm/webca ... 1&cl=US,EN

Another possibility is an analog microphone amplifier (which I also use) but those can run into serious money, or a USB audio adapter with a microphone input. There I'm a little fuzzier, but I also use a Startech USB to Audio adapter...

http://www.amazon.com/StarTech-ICUSBAUD ... B000NPKGGK

This will accept your microphone and drive your headphones. It turns your Mac into a PC.

If you are forced to use the equipment you have, start recording and don't talk for the first two minutes. Cut off the blank super-noisy segment in Audacity and noise reduce everything else. You may find that noise reduction is very much improved in Audacity 1.3. You can install both 1.2 and 1.3 as long as you don't use both at once.

Koz

[kozikowski]

A note on the ICUSBAUDIO. One of the ones at work produces a DC level in addition to the sound recording. This is easily fixed in Effect > Normalize > Remove DC Offset.

Koz

[leosmith]

Thanks Koz.

Are you plugged into the connector with the little circle and two black arrows icon? That's the MacBook high level Line-In. MacBooks don't have a Microphone-In like PCs do.

Oops, you're right.

One cheap way out of this is to buy a different microphone. I use the Logitech USB Desktop Microphone on my PowerBook (which has the same sound connections you do).

Sounds like our best solution. I'm in Thailand. Assuming I can't find this exact model, what specs do I need to look for when I go shopping?

If you are forced to use the equipment you have, start recording and don't talk for the first two minutes. Cut off the blank super-noisy segment in Audacity and noise reduce everything else.

Amazingly enough, this didn't work. The 2 minutes increased to 4 when we tried it. Then we tried shooting the bull for 2 min, thinking it needed to hear sound. It shifted to 4 again. She went back to normal reading, and it went back to 2. I'm pretty sure my computer is possessed.

You may find that noise reduction is very much improved in Audacity 1.3.

I think we'll try the new mic and install Audacity 1.3. Do you have any tips on how to best use noise reduction?

[kozikowski]

<<<I'm pretty sure my computer is possessed.>>>

I think you're just listening to the normal Mac housekeeping which nobody but you ever hears.

<<<Assuming I can't find this exact model, what specs do I need to look for when I go shopping?>>>

Low end microphones tend to "fudge" the specifications. I did the engineering acceptance on a headset we use at work. I just tried a bunch of them. I couldn't find any correlation between specifications and how they worked.

If you're doing production on a Mac, I would open iTunes Preferences > Playback and turn off Sound Check and Sound Enhancer. Those are fine if you're a glassy-eyed teenager enjoying his/her music, but they tend to fight special effects and hide errors.

<<<Do you have any tips on how to best use noise reduction?>>>

Sure, and right after that, I'll tell you how to play the violin and ride a bicycle. The people at work are always after me to put little pieces of tape on things so they know exactly where to set the adjustments. But the adjustments change--a lot--with each performer.

The noise reduction in 1.2 was easy, if frequently ineffective. One adjustment.
However, I often find it useful to achieve reduction just to the left of "Less."

Both of these packages seek to subtract the sample or profile from the show. If you accidentally get some violin in the sample in addition to the background noise, the violins will go, too. The additional controls under 1.3 give you "sloppy" adjustments. It's not unusual because of the way your ear works, that you really don't want to be surgically accurate when you do this. It can give you some really odd effects in the show. In 1.3 the amount of reduction is pretty simple, but the other two control how gently and how late the correction is applied. Skillful adjustment of those can make the difference between an acceptable performance and not.

One word on dB. The ear hears 18 dB as about half and double volume. It's very different from the amount of signal in the show. Blame your wacky ears.

Noise Reduction only works if the noise isn't moving. It's useless in getting rid of a metrobus starting up outside your window, but pretty good at the low air conditioning whine through the whole performance. If the air conditioner starts up or stops in the middle of the show, you're dead.

The violin analogy is pretty apt. I'm pretty good at this, but one of the posters showed me a better way to hold the bow and doubled my performance. He did something to the profile sound during sampling and got enormously better noise reduction. I gotta go back and read that again.

By the way, if you get a nice microphone, you won't need the noise reduction, so all this will be useless knowledge after the letter carrier shows up with your new mic.

Koz