[bandit1200]

I'm a newbie. I signed up specifically to ask the following question. (Not a troll

Question: Is there dynamic (volume) compression shareware/freeware available for .wav or .mp3s? How do folks feel about dynamic compression for portable audio?

Why: I like symphonies, I like open headphones, I like listenening in places that aren't absolutely quiet. But there's a problem.

Its not that my portable device isn't loud enough. Its plenty loud. Its just that the quiet passages in symphonic music are often too quiet. Especially with some ambient sound and open headphones. The detail of the quiet passages can get lost.

Turning up the volume isn't the solution. (1) When the player is maxed, the quiet parts still aren't loud enough. It's not that the player can't play any louder, its that there isn't enough gain to bring the quiet parts up to a reasonable level. (2) Even if the gain could be increased, then the louder sections could be too loud (painful) or would saturate and distort (worse than painful).

The solution of dynamic compression has been around for quite some time. In cases where ambient sound exists, compression can be used to bring quiet passages above the sound floor. The difference between loud and quiet passages is reduced -- when done well, this reduction in dynamic range preserves the relative differences in volume and can sound very good. Your brain gets used to it pretty quick.

This technique is often used in live performances, and also was used in the "old days" to make the most of the available dynamic range of media like audio tape and FM Radio. In fact, many record and tape recordings used a great deal of dynamic compression to "fit" all music into tape's intrinsic capabilities. This was and is often overdone.

[Too much compression can suck. Some of the older recordings I have could actually benefit from dynamic expansion....another story...(also, don't confuse this with dbx noise reduction, or headroom expansion stuff, even though there are similarities.)]

Modern recordings of symphonic music, for example, make use of CD's amazing available dynamic range and typically don't use compression. This is wonderful, especialy for home audio, but at the same time, it is the source of my problem when in portable mode.

So, I think I'd like a bit of dynamic compression for my portable audio. If well implemented, sound quality can remain very high, and real-world listenability of Symphonic music could be improved for me.

Since its not built into hardware, I guess I'll need to encode it into the .mp3's (Hardware is preferable, of course, since it would leave the source as-is...)

I don't know enough about the mp3 format to know if this can be done post-encoding, or if it would need to be done to the .wav files before encoding.

Can anyone give some insight here? What software is available? (freeware? Shareware?) Is there an easy way to do this? Am I nuts?

For that matter, does anyone beside me think that portable electronics firms might think about including a dynamic compression/expansion feature?

My car stereo (stock Ford cd changer) has dynamic compression (no adjustability, though) that works pretty well. How hard could it be to get iRiver or Creative to include it?


What do you think? I don't really want to switch to closed/earcanal phones -- too easy to get run over when jogging....


-Bandit

(In case you're wondering, I currently am using a SlimX350, PortaPro or PX100 (new!) or Airhead and HD600's)

 

[phonatic]

If you use a PDCP with MP3 playback or a Minidisc, AVLS might help. You can turn it up louder without blowing your phones or your ears.

Beyond that, you will probably need to use a waveform editor with a compressor/limiter function to achieve what you desire. Maybe Peak, Audacity, or CoolEdit, or something like that. I can't say for sure which one of those offers a limiter but I am sure at least one of them must.

I have the same problem you have and I have mostly solved it by just moving to a quieter spot for listening. There are definitely times when wide dynamic range can get to be too much of a good thing. For this reason, a lot of my listening on the go is jazz. I have even now and again had some trouble hearing quiet passages in say, Herbie Hancock's "Maiden Voyage" album. It can be a hassle.

 

[bangraman]

That's easy. Get an Eggo (D66 recommended, D22's not really... althugh they're OK). There's just a bit of sealing but more than open phones, and you can still hear what's going on outside.

 

[fredpb]

Goldwave might do that. I am not that familiar with all the software about.

When I used cassettes in my car I used to use a Shure compressor/limiter to compress my symphonic music. Worked well. Still have the compressor but don't use it with portable stuff.

Some CD rippers or MP3 encoders do have volume compensation, or "normalization".

 

[sacriste]

Normalization is a totally different thing, is good just to have the same maximum volume in all the tracks, but you still have the same dynamics. Is like multiply the entire track for the same number: the number you neeed to have the maximum level in the point you want (98% or other). Compression takes all the parts bellow a given value and rise them a given amount, so quieter parts sound louder but the maximum remains the same.
In the other hand, it adds even more artifacts (weird sounds) to the already weird sounding MP3s (sorry).
I second the semi-closed cans option.

 

[bandit1200]

I am unfamiliar with ALVS -- does this dynamically change the gain during a track? What players have this?

As far as encoding dynamic compression, I have not found much in the way of freeware/shareware to do this. I did find someone doing a plug-in for audacity, but it appears primitive -- I haven't tried it.

The more I think about it, the more appropriate it seems to have dynamic compression in hardware so it can be adjusted during playback. While it is certainly capable of screwing up the sound, it CAN be done well (and only when the environment warrants.) I am thinking about something similar to dbx's over-easy compression -- which, by the way, can sound very good.

From the reaction of the forum, I guess there isn't really much interest in getting dynamic compression for portable audio. Alas, closed headphones might be the only solution.

Thanks for the input.

-bandit

 

[phonatic]

I think just about all portable Sony players made in the past many years (MD, CD, probably MP3) have AVLS. Maybe others do, too. It's a basic gain limiter. I haven't played with it much. It is meant to protect your ears from loud transients... I see no reason why it couldn't do at least somewhat what you are wanting.

 

[redshifter]

i've done extensive companding/expanding of dynamics using cool edit pro. i think you can buy it or get a shareware version. in any case, it is very difficult to pull off convincing dynamic compression. you can end up with transient pumping and a dynamic brickwall. studios use dynamic compressors made by dbx and costing hundreds, thousands of dollars to ruin some of your favorite recordings.

in any case, cool edit is a good place to start, and good luck with your project. have fun!

 

[bandit1200]

Oh, I see. Unfortunately a limiter is not really what I am going after. The nice thing about a limiter is that it keeps the amplifier from going into distortion (saturation/clipping) by reshaping too loud sounds. The bad thing is that while your hardware is being protected by the limiter, you still get distortion of the loudest sounds (although better than clipping) due to this "reshaping."

I want to hear the loud stuff clearly as well....

With dynamic compression, both quiet sounds and loud sounds are essentially undistorted. Its the transitions where distortion might be noticable ('passing through the knee.')



Thanks!

-bandit

 

[bandit1200]

Thanks for the tip on Cooledit pro. Does the shareware version have compression/expansion? I'd like to try it. Is it as configurable as a real dbx box?

I agree studios should avoid compression as much as possible -- In the old days (80's) I used to find it useful for live performaces. (overcoming ambient sounds) Although there is a place for comression in the studio especially for individual tracks like vocals...its easy to screw up. Of course compressing classical music sources is a crime, IMHO.

-bandit

 

[redshifter]

Quote:

Originally posted by bandit1200 Thanks for the tip on Cooledit pro. Does the shareware version have compression/expansion? I'd like to try it. Is it as configurable as a real dbx box? I agree studios should avoid compression as much as possible -- In the old days (80's) I used to find it useful for live performaces. (overcoming ambient sounds) Although there is a place for comression in the studio especially for individual tracks like vocals...its easy to screw up. Of course compressing classical music sources is a crime, IMHO. -bandit

absolutely, classical should never be dynamically compressed, and fancy mic placements and effects should be kept to a minimum.

i have the full version of ce, so i'm not sure about the shareware. d/l it and see. what is useful with cool edit is you can see a graphic of the entire wave showing dynamic peaks and valleys. you can then set a number of expand/compand filters over the wave depending on level. for example, you can compress everything over 8db by 3% and expand sounds below 2db by 5%, and even more complicated compression functions can be applied. it takes time, but if you find something that works you can save the settings.

i was trying to uncompress a studio album (radiohead "ok computer") but it is very hard to fix overcompression. i could see on the cool edit graph where exactly the compression was applied--between the loudest instrument sound and the loudest drum hits--there was a straight line where the sound cuts off. so i set the threshold at that sound level--to effect only the drum hits that were cut off--and tried a number of different expansion settings. nothing sounded exactly right, there was more dynamics but there was pumping too. i also did minimal compression on the softest sounds too. i may experiment more in the future.

 

[bandit1200]

Thanks redshifter,

Sounds like the compression/expansion function is reasonably flexible. I'll give it a whirl.

BTW, the word "companding" is usually used to refer to the process of "encoding" a signal with dynamic compression for transmission (or storage) then "decoding" that signal with an exactly matching dynamic expansion to restore the original dynamic range. This technique was used in cassette dbx noise reduction, for example. The tape recording was compressed during production then expanded during playback on the cassette deck. This had the effect of not only extending the dynamic range of audio tape, but of of lowering the sound floor of quieter passages. Hiss thus reduced. During loud passages hiss wasn't reduced, but you couldn't hear it anyway (due to masking). Kinda cool, but never seemed to take off in the consumer world.

As you noticed, you need to match the compression and expansion very well when companding otherwise the result can be pretty bad.

In any case, thanks again for the help.

-bandit

 

[redshifter]

yeah, thanks for the clarification. i hope you knew what i was trying to say anyway.

i have an old cassette deck that uses dbx and dbx disc (for dbx encoded records!). i always liked how dbx destroyed the noise without cutting off high frequency, although once in a while i could hear noise pumping.

still, it was miles ahead of dolby b.

 

[dparrish]

I really think your easiest solution is to be happy wearing some phones that are a bit more closed. I must admit that I'm not versed enough on what the best choices would be. Classical music really is MEANT to be dynamic, and in my opinion, this is where is shines compared to most pop music.

I'd recommend that you call Todd at HeadRoom and ask him for an opinion on a "semi-closed" phone suitable for your purposes.

As for me, I carry my EtyER4Ss around with me for listening to jazz/classical. When I want to be more aware of my surroundings, I just pull them out of my ear slightly.

David

 

[forumaudio20]

Bump!
 
It has been a long time since a post was added to this thread. Maybe there will be newer information.
 
I am also interested in the answers to the questions posted in post #1.
 
I will make my personal summary and ask my own question in a short concise manner:
 
For symphonies, classical, and some OSTs is there a way to increase the volume of the quiet parts while maintaining the volume of the louder parts below hearing loss levels?
 
Is there anything else that might help? I am using headphones, pc, and possibly a headphone amplifier.
 
My issue more computer audio related: http://www.head-fi.org/t/600578/increase-volume-of-quiet-parts-and-maintain-volume-of-loud-parts-beneath-hearing-loss-levels#post_8218453
 
Thanks.