Subject:what IS dynamic range?

Posted by: whitepony

Date:1/28/2003 2:24:59 PM

yep, that's my question:)

Subject:RE: what IS dynamic range?

Reply by: kilroy

Date:1/28/2003 4:11:00 PM

All the good stuff between the quietest and loudest swings in the amplitude range of your music. The same stuff that everyone seems so bent on doing away with these days. The same stuff your hear on great sounding albums like Pink Floyd's Dark Side Of The Moon, anything Steely Dan, and host of other well engineered records back before we had the excessive hyper application of compression and brickwall limiting.

Yep, that's my answer.

Man I must be old...I can actually still remember what it's like to be able to listen to a record all the way through without wearing out my ears.

Subject:RE: what IS dynamic range?

Reply by: philsayer

Date:1/28/2003 7:21:13 PM

Up to a point I agree with kilroy. It's ironic indeed that thanks to digital sound, the potential for greater dynamic range is there to be exploited far more, since the medium itself is noiseless, unlike analogue recordings on tape or vinyl... and yet everything is squeezed to death, with a dynamic range of about 10dB. Madness, arguably.

Indeed, dynamic range is the difference between the loudest and the quietest noise on a recording. In reality, recorded sound (both speech and music) is almost always compressed and limited to some extent (note that kilroy refers to excessive hyper application....)

Compression and limiting essentially makes the quiet bits louder and the loud bits quieter, thus reducing the dynamic range, but at the same time having some benefits. In speech recording, it's possible to listen at a lower overall level without missing the quietly-spoken bits (which is part of the reason speech radio is compressed.) That also applies to music, too, and dance music especially, where the audience wants a thumpy, compressed sound - it also enables the sound system in the club to be run close to the maximum all the time without distorting, since there are no vicious peaks to create it!

In addition, used creatively in music, compression and/or hard limiting can be used to create interesting effects - a perfect example is an old track of Traffic's from the mid-sixties called "Hole In My Shoe." The effects on the intro and elsewhere were achieved by very heavy compression of the drum track - the cymbals, struck at the same time as the bass drum, rapidly gain volume as the shorter bass drum thump decays.

For radio transmission, even FM, compression is used to mask the unwanted noise of the transmission medium itself, but some broadcasters do this manually, i.e. by riding the faders. (Technically, that's still compression, by the way!)

Allied to dynamic range is signal to noise ratio (S/N ratio.) This is simply the ratio of wanted noise (music, speech) to unwanted noise (maybe tape hiss, turntable rumble, transmission noise, etc.)

Dynamic range is one of a number of parameters of quality in a number of audio-related products. Essentially, the greater the dynamic range, the better, whether it's an amp, speakers, mike or computer sound card, simply because it is capable of processing a wide range of sound levels before distorting or attenuating (reducing) the signal.

I welcome challenges/corrections on all the above points, but i'm reasonably sure that's it in reasonably non-technical terms!

Subject:RE: what IS dynamic range?

Reply by: whitepony

Date:1/28/2003 9:48:16 PM

hmmm, well, not to agree or disagree with kilroy, i'll just say that's not what i had in mind.

a couple things i am not clear on: a dynamic range of 10db means the loudest note is only ten db louder than the quietest? so what about like, when a song is fading out, and you have to turn the volume WAY up to still hear it?

and also, if i wide dynamic range is what you want, why do producers(or whoever) squeeze it all to 6-10db?

thanks

Subject:RE: what IS dynamic range?

Reply by: MJhig

Date:1/28/2003 10:16:08 PM

philsayer gave an excellent laymen's terms, now and then description.

"a dynamic range of 10db means the loudest note is only ten db louder than the quietest?"

Yes.

"if i wide dynamic range is what you want"

It's not necessarily what everyone wants or the given material requires. There are no rules along these lines like in art where if you mix blue with yellow you get green. This is a very subjective area. As kilroy points out in classical music you would generally want to maintain as wide a dynamic range as possible and as philsayer points out with top 40 dance you generally want it squashed.

MJ

Subject:RE: what IS dynamic range?

Reply by: whitepony

Date:1/29/2003 10:17:47 PM

mkay, i hope this isn't too far off topic, but it's something also on my mind. when you are recording (say, a guitar track), do you want to go ahead and compress it so that no clipping occurs, or is compression usually done later on?

Subject:RE: what IS dynamic range?

Reply by: MJhig

Date:1/29/2003 10:47:38 PM

If when you ask; "do you want to go ahead and compress it so that no clipping occurs"
you mean apply a compressor/limiter to the signal on the way in then "generally" speaking, no. Effects applied to the recorded signal cannot be undone. If at all possible check the recording levels while the instrument/signal is at it's hottest/loudest level and set the recording level as close as possible but below 0 dB and apply effects post record. Record at 24 bit if possible.

My experience has shown that guitar players are notorious for keeping their volume lower during sound-check then cranking during the live performance or recording. If you are not the guitar player impress upon them that this behavior will produce disastrous results.

MJ