Back when CDs were in the process of taking over from cassettes, I heard that one of the cool things they’d be able to do with digital music was to give you a switch on the CD player that would compress the dynamic range of the music.
This feature would allow you to listen in a noisy environment (like my van - Honda really has to do something about the road noise thing) without the quiet bits disappearing or the loud bits blowing out the speakers (and my ears, and the windows).
So where is this feature? I’ve been looking around for a CD player that has it, to no avail. The sales guys at the audio stores have no idea what I’m even talking about. Google only turns up articles complaining about the rampant use of compression in the mastering process.
I thought that it was standard on almost every consumer CD player? Offhand, my home stereo, car stereo, and AV reciever all have some form of compression available to “even out” the sound.
I’m a broadcast sound engineer, and a gear-head, I’ve never seen such a device.
But, as you mentioned, all the ranting about current mastering procedures is true; you don’t need to compress the dynamic range of your CDs anymore… they’ve done it for you.
I haven’t seen them on car radios but it sounds like a good feature.
The only place I have seen them is on Home Theatre receivers.
It’s so when you watch a movie you aren’t constantly changing the volume level from “what did that guy say? turn it up. I can’t hear them whispering like that.” to “damn, all those explosions and gunshots are loud! Can you turn it down?”
It makes the quieter stuff louder and the louder stuff quieter.
Earlier, higher end, end portable CD players did have an on-off compression switch, usually hidden in the battery compartment or inside the clamshell lid. IIRC at some point compression circuitry in portables just became a standard “always on” part of the playback and the switch was often eliminated. The reasoning was that an uncompressed wide dynamic range (from a CD) was not likely to appeal to 99.9% of the people listening through headphones who would probably lose the quiet bits and be overloaded by the loudest.
I appreciate the info, guys. It took me a while to snap to the follow-up question, though:
Since this can be done in the mastering process, what sort of software does it take to do it myself? Does it take a professional mastering package, or is there something more easily available? And hopefully it’s something that can work on the CD as a whole, not song-by-song.
I would think (and fishbycycle can paddle me with a mike stand if I’m worng) that converting a song to an MP3 would essentially do much of the same thing and effectively compressess the dynamic range of the song. Even if you re-expand the MP3 back to a Music CD song, once the MP3 lossy compression takes place it’s permanent. There are dozens of mp3 ripping/playing/burning packages. MusicMatch and Winamp are among the most popular.
Possibly… it was my understanding that part tof the MP3 compression process involved compressing the dynamic range of the music to some extent, along with eliminating (purportedly inaudible) information at the hiigh and low ends of the audio frequency spectrum. I’ll will sit corrected if wrong.
It’s a widely available feature that you can find in almost any audio manipulation program. I’ve seen it go by several names – compression, dynamics, limiter, and “wave hammer”, come to mind.
This is a great feature if you’re preparing a CD or cassette for a noisy car trip. Most programs will allow you to tweak the parameters so you can find a good balance between subtle compression and complete, wacked-out distortion. (Compressors are often used on electric guitars and basses to change the quality of the notes or create distortion).
I use Sound Forge personally, but that may be a little bit of an overkill for your needs. Check out some of the freeware and shareware offerings on the net.
I’ve got many new classical music CDs whose dynamic range is suitable only for a concert hall. It’s frustrating, really. FWIW, I can think of no other genre with such dynamic range as orchestral.
Classical music recording is still pretty much a pure science, where engineers strive to protect the dynamic range of music, and have it reproduced as naturally as possible. You can have a CD of classical music that has 60 dB or more of dynamic range. To compress that would be an injustice to the composer and the performers. Their ppp needs to be ppp, and when they go fff, it needs to be able to knock you over.
On the other hand, popular music recordings are amplified to 0 dB and have between 12 and 24 dB of gain added. Rather than having the natural ebbs and flows of the dynamics of music, everything is as loud as everything else. Viewed in a waveform editor, the waveforms of these songs look solid. No peaks and dips, just a solid waveform from the bottom of the screen to the top, all the way across, until the fade-out. For this kind of recording atrocity, compression in CD players is unnecessary. It may exist, but you don’t need it anymore.
Conversion to mp3 does not alter the dynamics, it only removes aural information to make the filesize smaller. This is why I asked astro in another thread why he felt it was necessary to convert wav files to mp3 to manage them, and back to wav to make CDs. All you get is a song that used to be 40 MB, that has been irrevocably reduced to 3 MB, and then padded out with digital zeroes to equal 40 MB again. But that was another thread…
Yes, I believe that is correct. And also the reason why mp3 files played on my MP3 compatible car deck sound absolutely horrendous.
I think MP3 sound was meant for walkmans and nothing else.