Yet Another Volume Question

[ds2]

I have some older cd's where the volume level is especially low. I've figured out how to increase the volume using Audacity, but I'm trying to clarify one thing that seems to continuously slow me down or makes me repeat the process. When I used to record to cassettes, I could set the volume level so it would only occasionally reach the 'red' zone (i.e clipping,distortion, etc) at certain points during the song which resulted in a decent playback volume w/o distortion. This was easy because I could tell if the level was set too high since the meter on the cassette deck went above the zero mark whereas the meter on Audacity stops at zero. My question boils down to: should I just try to get the volume closest to the zero mark on Audacity and that will produce a respectable volume?

I'm trying to alleviate increasing the volume, burning it to a new disk, then finding out it's not much better than it was, or increasing it too much and not knowing it. I know each cd may need more/less increasing, but I'm just trying to get to a 'general' point without so much guessing involved. Like I said, because Audacity stops at the zero mark, I can't tell if I'm potentially increasing the volume too much, but in other cases, I may not have increased it enough.

Hope this is clear enough for an answer---thanx much for any and all help!

[kozikowski]

The older Music CDs were pressed with the Red Book standard audio level of -17dB, 0 being maxed out. This results in a reasonable volume for the music and the ability to go significantly over without damage. Actually hitting digital Zero is deadly. So -17dB was Zero VU on your tape machine. Please note that even if you did go over zero on your machine, that didn't guarantee damage, it just made it more likely. The specification for a VU meter is "Occasional peaks into the red."

Time Marches On.

I have a Trance CD that is recorded at 0dB digital. All of it. The waveform for this song looks like a solid block of blue with no variation whatever. It looks like somebody took a Sharpie® to the screen. You can do that if your music has no volume variation. If you tried that with Brucker's Ninth Symphony, you would die a quick death.

Audacity has some tools that can help, Normalize and Amplify. Both have automatic settings. What they do, and this is important, is reference the loudest part of a performance and change the whole performance until that point reaches a determined value. Normalize does it to left and right differently, Amplify does the same thing to both left and right. Both tools are much better in Audacity 1.3. you can put both Audacities on your machine as long as you only use one at a time.

This can get you in the ballpark very quickly with minimum of work, although technically, neither tool pays any attention to performance loudness.

You can get killed with this. If your stylus goes over a cat hair while transferring a record, the hair will now become the dominant, significant part of the performance. Ask me how I know that.

Koz

[ds2]

Thanx for all the info--I appreciate it. I've been using the Amplify function so far which is where my question came into play. I'm only updating cd's so I won't have to worry about the 'cat hair' scenario I'll also have to double check which Audacity version I'm using.

So would you suggest that getting the volume closest to zero should suffice? Should I maybe use the Gain slider instead?
I have some cd's where the original volume is so low it's ridiculous.

Thanx again!

[steve]

So would you suggest that getting the volume closest to zero should suffice?

Yes, but it must not go over or distortion will occur.

Should I maybe use the Gain slider instead?

Much easier to do with the "Amplify" effect.

It is debatable whether it is necessary to leave "headroom" if you are just going to burn it back onto a CD. If you select the entire track and use the default settings in "Amplify" the result will have a peak amplitude of 0 dB. Personally I find this works well, but if you prefer to leave a little headroom, reduce the amplification amount a little (say by 0.1dB)

Rather than recording the original CDs in Audacity you would get better quality by "ripping" the CD (digital extraction). You can do this with a program such as C-Dex (it's free and very good). C-Dex will produce a WAV file which you can then open (Import) into Audacity for amplification.

[ds2]

Ah, ok---I'll give that a shot. Currently I was ripping them to Wave files in Windows Media Player, importing them to Audacity, messing w/the volume, then exporting back to WMP to burn the disk.

Thanx much for your input!!