Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Do I need compressor at output of each DolbyDigital channel?

Status
Not open for further replies.

bimbla

Advanced Member level 1
Joined
Jul 13, 2001
Messages
418
Helped
23
Reputation
46
Reaction score
8
Trophy points
1,298
Activity points
3,597
Digital Audio...

Is a compressor at the o/p of each Dolby Digital channel a must?

Thanks and regards.

bimbla.
 

Re: Digital Audio...

I don't think so. Because compression is distortion; maybe desirable distortion but distortion anyway. And Dolby processed signal are also high fidelity; which should always be divorced from distortion content.
Miguel
 

Re: Digital Audio...

The dynamic range is too high for comfortable listening at any volume. Loud passages are too loud while the soft dialogues are almost inaudible.

How does one tackle this then?

bimbla.
 

Re: Digital Audio...

Hi bimbla.
You tackle that behavior exactly as you mentioned: with a compressor.
But its use is not a must as you asked.

Using the compressor, the loud and soft passages or REAL music would not be there, just as listening to typical FM broadcast.
One of the advantages of digital audio is exactly that, the capability of reproducing a DESIRED much wider dynamic range of nearly 90 deciBels, just as standing in front of an orchestra. That is real fidelity sound. Interesting you do not desire that.

Compression has its artificial conveniences, as loudspeakers cannot reproduce the REAL audio as for example in war movie when soldiers have a dialog while shooting... The shot volume cannot be reproduced at its real level by a speaker.

When the program material is punk rock, the dynamic range is very small, and the level is uniform, and you do not perceive the need for compression, but for many, that is not exactly perceived as music either.

Miguel :)
 

Re: Digital Audio...

With due respect to the digital technology.....

Imagine yourself in a movietheatre in India.
Capacity crowd of 5500 to 650......First week. They enjoy their hindi movies and are loud in the theatres.
You have to strain yourself to hear the dialogues while the action scenes and songs starts to 'HIT' your ears.

Hence the need is felt for a compressor.

Yes..... I am talking Movie theatres and o/p of Dolby DA-20 Digital decoder.

bimbla.
 

Re: Digital Audio...

Hi bimbla.
I am sorry, I cannot imagine myself in an indian cinema sorrounded by noisy public. I would run fast away from that behavior.
Something I learned once : The louder your public is, the softer speaking you have to be. And works. The public mutes immediately to attempt hearing, that is what they paid for.
Compressing signal may direct you to an spiral, making everything unbearably and uncomfortably louder.
You may compress but amplify to lower levels. It may work.
Good luck processing audio,
Miguel :)
 

Re: Digital Audio...

Compress and amplify to a lower lever.....Yes, I think you and I are having the same line of action.

However odd it may seem, but an engineer has to adapt to real life situation.

By the way, don't you think it (large dynamic range) is annoying in homes also?

I thank you for your views and early reply. Do you work in audio? Are you connected to Cinema?

bimbla.
 

Digital Audio...

i have some experiant in dolby NR
and dolby ac-3
can you tell ,the main question ?
and plz tell what do you want ?
 

Re: Digital Audio...

Hi bimbla.
No, I prefer the large dynamics at home... a VERYQUIET home. Annoying is the noise.
Yes, I work in audio processing manufacturing all day; every day, with equipment for broadcasting: www.orban.com
Miguel
Audio recording engineer
 

Re: Digital Audio...

How do you handle the Compression Drivers (Horns)? They kill the ears!

bimbla.
 

Re: Digital Audio...

Hi. Compression driver horns are mainly for long distance reach, as exteriors use. Just lower the volume for their particular frequency range.
Miguel
 

Re: Digital Audio...

i noticed whilst on jury service that experienced people to a court of law spoke in low but booming voices if you could not be heard the judge would soon tell you. but at home i am for ever altering the volumne on my tv
 

Re: Digital Audio...

Its a pity that Horns are still used (not just in India but all over the world)
in movie theatres.
In the days of valve amps, it was needed to 'reach' the sound. The amps were then rated at 100Wrms.

We still use horns when the amps are rated at 2500Wrms.

Isn't it amusing that no substitute is found?

bimbla.
 

Re: Digital Audio...

At home while watching TV, I dont' mind changing the volume from one movie to next.

But for the same movie, volume chould be consistant.

bimbla.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top