What is compressed??

On My Adcom GDV-750 dvd-a player is has the option to compress the analog outputs. What I want to know is it has off up to full. so is off compressed? or is the full setting compressed? and what difference will it make?please help
not familiar with your dvd player, but compression is when you limit the peak to peak height of the waveforms--in other words, there is less difference between loud sounds and soft sounds.

Imagine listening to a piece of music that includes everything from an oboe solo to full orchestrel ffff blast on your car radio. You would constantly be changing the volume... compression takes care of that by making what were loud & soft noises similar in level.

Hope that help,
Generally speaking, off is off, and full, more than likely, is on. Fully on, that is to say.
Compression refers to dynamic range. This is the difference in amplitude (loudness) from the most quiet sound to the loudest in the program material. Compression is used to reduce the difference, it is used to make recordings sound better on equipment that cannot reproduce large dynamic swings or spikes. In other words, compressed music sounds better on cheap systems or jam boxes.
Much of the recorded material commercially available is compressed to cater to the mass market (cheap stereo and jam box) consumers. This is a sad state of affairs for those who aspire to high end playback systems. There was a lot of buzz about this a few years ago when Santana put out 'Supernatural', an otherwise great CD marred by compression.
Not sure how your CD player control works. If your system can handle it, you should notice greater dynamic range (wider difference between quiet and loud) when the signal is not compressed.
Hi Harnellt,

Most probably that feature is included on your machine to provide greater control when you listen under less than optimum conditions. When listening at low volumes or in areas of high ambient noise the very softest passages in the music may be masked. Adjusting for less dynamic range will limit the peaks of the music but also make the softer passages more pronounced by allowing you adjust the volume control higher than you would without the control enacted.

Best Regards,

Barry Kohan
That control may also let you make recordings for use in your car which has relatively high ambient noise levels.


Compression can be good in a car stereo. Also, for a while 'limiters' were real popular when televisions cranked up the signal when commercials came on. If you want to hear what I am talking about, try Fox Network. The limiters would make sure the commercials don't sound any louder than the average signal strength of the show you were watching.
Examples where compression is IMPORTANT.

Forget the car stereos or XM radios.

Take the microphone and start speaking SIX... SIX...
You will hear distortion in the speakers. The sencitive device reacts differently on the air motion depending what you're saying...

A self-confident guitar player gets so involved that he/she forgets about pressure on the strings during the studio recordings or the live performance(Jimi Page for example)...

Hence you can't get arround without compression in any studio or live recordings/performances.

A producer is going to compile various selections from different albums or even from different artists. Every recording originally has a different initial level. A compilation should have one recording level throughout entire album.

A simple compression device would decrease gain on the high signal and increase gain on the low signal which will give a possibility to overall increase the initial level of the recording. A complexed compression device would include a proccessor and software which will allow to customize compressons depending on the task you're facing...