[crowby1]

Probably a really easy question to answer, but if I have Dolby Pro Logic II mode selected on my Panasonic DVD cinema system, and I play a DVD with a 5.1 soundtrack on it, am I getting proper 5.1 or simulated Pro Logic II surround sound?

From reading the manual it looks like this mode applies the simulated surround effects to standard stereo sources and 5.1 surround if the original source is 5.1. Am I correct in this assumption?

Incidentally Pro Logic II sound so good I am hard pressed to tell the difference.

[grahamlthompson]

Quote:

Originally Posted by crowby1

Probably a really easy question to answer, but if I have Dolby Pro Logic II mode selected on my Panasonic DVD cinema system, and I play a DVD with a 5.1 soundtrack on it, am I getting proper 5.1 or simulated Pro Logic II surround sound?

From reading the manual it looks like this mode applies the simulated surround effects to standard stereo sources and 5.1 surround if the original source is 5.1. Am I correct in this assumption?

Incidentally Pro Logic II sound so good I am hard pressed to tell the difference.

It's hard to say but my Denon amp displays Prologic when recieving DD 2.0 and Dolby Digital when its DD5.1.

[crowby1]

Quote:

Originally Posted by grahamlthompson

It's hard to say but my Denon amp displays Prologic when recieving DD 2.0 and Dolby Digital when its DD5.1.

This just has a green light that says "surround output" and it's always on.

[Willie Wontie]

Pro-Logic II is an analogue surround sound mode achieved by taking the analogue stereo signal and generating pseudo-surround (centre and rear) signals from the stereo signal. It often can be very effective - but it isn't true Dolby Digital 5.1 surround sound.

[grahamlthompson]

Quote:

Originally Posted by Willie Wontie

Pro-Logic II is an analogue surround sound mode achieved by taking the analogue stereo signal and generating pseudo-surround (centre and rear) signals from the stereo signal. It often can be very effective - but it isn't true Dolby Digital 5.1 surround sound.

Prologic 11 works with digital sound as well as analogue. HD TV programming is frequently transmitted with dolby digital encoding but having only two discrete channels (DD2.0) as distinct from the lower quality PCM mpeg 1 layer 2 system used by Freeview and most SD sateliite channels. Both systems are digital though. The original Dolby Surround only works with analogue signals as it's a matrix system

http://en.wikipedia.org/wiki/Dolby_Pro_Logic

[Echo1]

Ah! So id DD2.0 superior to PLII?

[crowby1]

Can anyone answer my original question? I understand the difference between 5.1 and pro logic, but which am I getting if the source dvd is 5.1 and the player mode is dpl II?

[JEFF62]

i would have thought 5.1 as it would presumably play the proper source first. I think DPL2 comes into play when there is not a 5.1 track and only dolby surround. I have a sony amp and a case in point is Doctor Who the other week which detected a 5.1 signal but only outputted from the front speakers. However I could not change it to dpl2 mpode to make the surround effect. Because the amp assumed it had a 5.1 signal already.

[grahamlthompson]

Quote:

Originally Posted by Wash

Ah! So id DD2.0 superior to PLII?

Dolby Digital is the system used to encode the sound as is Mpeg1 layer 2. Prologic 11 is the system used to extract surround sound information from the stereo data. Dolby Digital sound has less compression, a higher frequency range and a wider dynamic range than mpeg so the sound is better whether it's processed to surround sound or not. The other system used on DVDs but afaik is not broadcast is DTS (Digital Theatre System) this is even less compressed than DD so offers even better sound.

As another poster says the beeb dropped a clanger with the Dr Who HD soundtrack transmitting a 5.1 flag when the sound was only 2.0

[crowby1]

Quote:

Originally Posted by JEFF62

i would have thought 5.1 as it would presumably play the proper source first. I think DPL2 comes into play when there is not a 5.1 track and only dolby surround. I have a sony amp and a case in point is Doctor Who the other week which detected a 5.1 signal but only outputted from the front speakers. However I could not change it to dpl2 mpode to make the surround effect. Because the amp assumed it had a 5.1 signal already.

Sounds like the answer I was looking for.

This has a number of modes, Standard (plays whatever the signal actually is), multi channel (plays stereo sound out of both pairs of speakers), DPLII movie and DPLII music.

What I like to do is just leave it on DPLII movie so that I get 5.1 whenever I have a 5.1 dvd on and pro logic pseudo surround whenever I am watching a stereo broadcast. I think this is what I am getting.

[grahamlthompson]

Quote:

Originally Posted by crowby1

Sounds like the answer I was looking for.

This has a number of modes, Standard (plays whatever the signal actually is), multi channel (plays stereo sound out of both pairs of speakers), DPLII movie and DPLII music.

What I like to do is just leave it on DPLII movie so that I get 5.1 whenever I have a 5.1 dvd on and pro logic pseudo surround whenever I am watching a stereo broadcast. I think this is what I am getting.

If you want to be certain get hold of a 5.1 test disc. I had one that came free with a magazine and it has channel ID and level check routines.

Example

http://www.britishaudio.co.uk/testdvds.htm

You can make your own on a PC if you have a video editor that can output dd5.1 (ac3)

[crowby1]

Another question around the same area.

I have set my Sky+ box to Dolby D in the optical audio output settings, and have Sky connected to the Home Cinema System via Optical cable, and yet I don't seem to be getting surround sound unless I turn on the Dolby Pro Logic mode (tried various films on Film4 that are marked as DD on the guide).

The Standard mode on this Panasonic system will apparantley play the sound however it is intended to be heard, so I would expect to hear Dolby surround. When it's on Standard though there's nothing coming through the back speakers.

Anyone know where I'm going wrong?

[titcaptain]

I'm not aware of Film 4 broadcasting in 5.1.
You will only get surround sound from non DD broadcasts by switching on the Pro-Logic 2 - thats what its for.
Select the Movie mode and not music.

You should have an AUTO setting somewhere so that the amp switches to DD when it receives a 5.1 track and then stays in PL2 for everything else.

Standard mode is probably stereo.

Pro-Logic is what creates the surround sound out of a 2 channel soundtrack, you won't get rear speaker sound without it unless you use some of the other fake processes for jazzing up stereo cd playback

Note that if you connect a PS3 to your Panny all in one you will not be able to get full 5.1 from DTS tracks if recent experience including my sons Panny is anything to go by

[RobAnt]

DTS and DD5.1 are analagous. That is they both contain 6 discrete channels of sound.

Dolby Pro Logic is normally encoded within a two channel (sometimes, erroneously, called stereo) package. Therefore the channels are NOT discrete. The 5 channels are encoded within two channels, using out of phase and other techniques, making it fully stereophonic compatible.

Whether or not these audio formats are delivered by analogue or digital mediums is pretty much irrelevant. You may find some sources (such as the sound card in a computer) have the ability to deliver discrete channels of sound via analogue outputs or a single digital output. You choose.

A turntable, for instance, decodes the information directly at the point of collection - the groove on the record excites a small electric motor mounted above the stylus pickup.

A CD player, on the other hand, may decode the data itself and present a pair of analogue outputs, or a single digital output for decoding by an amplifier with it's own DAC (digital to analogue converter). You can choose on the basis of either the quality of the DAC in the player is better or the DAC in the amplifier.

The same goes for a Set Top Box , DVD or Blu-Ray player. Although some may not give you an option.

Stereophonic is two discrete channels of sound, in the same way that monophonic is one channel of discrete sound.

[RobAnt]

Quote:

Originally Posted by crowby1

Can anyone answer my original question? I understand the difference between 5.1 and pro logic, but which am I getting if the source dvd is 5.1 and the player mode is dpl II?

If you connect your player to your amplifier via an optical cable, and the amplifier is capable of decoding DD5.1, then it is highly likely that it will auto detect that and not allow you to change to DPL.

Without knowing prcisely which receiver you have it isn't possible to determine exactly what you're listening to.

[derek500]

Quote:

Originally Posted by crowby1

I have set my Sky+ box to Dolby D in the optical audio output settings, and have Sky connected to the Home Cinema System via Optical cable, and yet I don't seem to be getting surround sound unless I turn on the Dolby Pro Logic mode (tried various films on Film4 that are marked as DD on the guide).

Film 4 do not transmit in DD. I don't know why they put it on the EPG!!

The only non HD channels in DD are the Sky Movie channels and a couple of Disneys.

Your amp is acting normally on Film 4.

[bobcar]

Quote:

Originally Posted by RobAnt

A turntable, for instance, decodes the information directly at the point of collection - the groove on the record excites a small electric motor mounted above the stylus pickup.

Not meaning to be picky () but it doesn't use a motor but a generator, you'd use a motor if you wanted to record onto the record. (Although of course if you were to feed an electrical signal back into the coil it will function as a motor).

[frasera]

any prologic or dd2 were just stop gap solutions back before dvd and digital transmission/hdtv. unless your reciever is smart enough to go back to 5.1 discrete when needed don't leave it in any prologic mode. that mode just faked lower resolution surround channels based on clever coding, its nothing compared to the 5.1 we have now. most dvds should be 5.1 anyways. i don't remember when i last saw a prologic dvd:P if ever... thats stuff of the vhs/laserdisc era and not everything has to be surround.:P

[grahamlthompson]

Quote:

Originally Posted by frasera

any prologic or dd2 were just stop gap solutions back before dvd and digital transmission/hdtv. unless your reciever is smart enough to go back to 5.1 discrete when needed don't leave it in any prologic mode. that mode just faked lower resolution surround channels based on clever coding, its nothing compared to the 5.1 we have now. most dvds should be 5.1 anyways. i don't remember when i last saw a prologic dvd:P if ever... thats stuff of the vhs/laserdisc era and not everything has to be surround.:P

This is just plain wrong Dolby Digital 2.0 is the samel dynamic range full frequency transmission same as 5.1 and requires the same decoder as 5.1 to decode it. It happens to have only two discrete channels with surround sound info matrixed onto the two channels leaving the cross over frequency set for your subwoofer to create the bass channerl. It's not as accurate as 5.1 in placing sound effects but it's still pretty convincing. The sound quality is however identical. Any decent amp will switch to prologic 11 surround sound processing when receiving DD2.0 and back to 5.1 when required it still uses the same decoder.

Apart from bluray advanced surround tracks all digital sound is compressed using lossy techniques the more compression the worse the sound. Broadcast TV uses the following standards

All Freeview and SD Satellite (apart from a couple of Sky Premium channels)

Heavily compressed mpeg 1 layer 2 PCM stereo markedly inferior to the nicam digital stereo used in analogue TV

HIgh Defintion Satellite (And I guess HD Freeview)

Much less compressed Dolby Digital in either 2.0 or 5.1 formats

DVD's can also carry even less compressed sound using the DTS system (Digital Theatre Sound)

[Deacon1972]

Quote:

Originally Posted by frasera

any prologic or dd2 were just stop gap solutions back before dvd and digital transmission/hdtv.

How would you get DD2.0 if there was no DVD/digital transmissions/HDTV?

Before digital there was only analogue and DPL.

[grahamlthompson]

Quote:

Originally Posted by Deacon1972

How would you get DD2.0 if there was no DVD/digital transmissions/HDTV?

Before digital there was only analogue and DPL.

I completely fail to see the point of this posting. Broadcast digital sound started in 1986 with the first digital stereo sound used in the UK using the Nicam sound system on UHF analogue TV transmissions. Some broadcasts were available using dolby surround with a suitable decoder and the system is compatible with Prologic and prologic 11 decoders. To this day this system is superior to the SD digital TV system in use today (mpeg 1 layer 2 pcm).

Digital sound was available some years before this on CD's using 16 bit 44Khz sampling. To this day many dvds (especially music ones) have PCM stereo soundtracks with the sample rate increased to 48Kkz because of the superior sound compared to Dolby Digital. Digital sound is not superior in quality to a good quality analogue FM transmission anyway as all digital transmissions are trade off between quality and bandwidth. In effect an analogue system is the same as a digital one using unlimited sampling rates.

You stated, not leave an amp in prologic mode. This is wrong if you are using and hearing a DD2.0 track the amp must have a DD decoder selected, in this case a switch from 2.0 to 5.1 will be completely automatic

[Deacon1972]

Quote:

Originally Posted by grahamlthompson

I completely fail to see the point of this posting.

It was easy to understand.

frasera said "any prologic or dd2 were just stop gap solutions back before dvd and digital transmission/hdtv."

So how could you get DD2.0 before DVD/digital transmissions and HDTV - you couldn't.

Quote:

Originally Posted by grahamlthompson

Broadcast digital sound started in 1986 with the first digital stereo sound used in the UK using the Nicam sound system on UHF analogue TV transmissions. Some broadcasts were available using dolby surround with a suitable decoder and the system is compatible with Prologic and prologic 11 decoders. To this day this system is superior to the SD digital TV system in use today (mpeg 1 layer 2 pcm).

But you still wouldn't have been able to get DD2.0, the best you'd get would have been DPL, even though NICAM was digital it was still analogue based, the only output on the TV's back then was analogue. Digital outputs only surfaced when Toshiba introduced it's Dolby Digital capable set, this was to compliment the new format that was DVD. But then you still wouldn't have got DD2.0 from Nicam, the only source you can get Dolby Digital over the air is satellite/cable, and the first to do that was Sky when they introduced Sky+.

Quote:

Originally Posted by grahamlthompson

You stated, not leave an amp in prologic mode. This is wrong if you are using and hearing a DD2.0 track the amp must have a DD decoder selected, in this case a switch from 2.0 to 5.1 will be completely automatic

I stated nothing of the sort......

I think you have your wires crossed with someone else.

[grahamlthompson]

Quote:

Originally Posted by Deacon1972

I stated nothing of the sort......

I think you have your wires crossed with someone else.

So I did sos but still can't see the point of the posting What point were you trying to make ?

[Deacon1972]

Quote:

Originally Posted by grahamlthompson

So I did sos but still can't see the point of the posting What point were you trying to make ?

How could DD2.0 have been a stop gap solution back before DVD/digital transmissions and HDTV - before all this technology arrived everything was analogue based, the best you got was DPL.

DD2.0 only started to be come available when the digital era started with laser discs, DVD and Sky+, then you could have anything from DD1.0 -> DD6.1.

DPL I suppose could have been seen as a stop gap until Dolby Digital arrived, but not DD2.0, this format is apart of the digital technology we have today.

[chrisjr]

Quote:

Originally Posted by grahamlthompson

Digital sound is not superior in quality to a good quality analogue FM transmission anyway as all digital transmissions are trade off between quality and bandwidth. In effect an analogue system is the same as a digital one using unlimited sampling rates.

You really think FM radio broadcasts are truly analogue?

The last bit in the chain, the transmitter may well be analogue but everything leading up to it is likely to be digital.

Very few FM transmitter sites that I know of are fed by analogue circuits any-more. much more likely is they use a digital system delivered by a BT kilostream.

Most Arqiva sites will use the APT WorldNet RIO unit which uses a APT-X codec usually at something like 384kb/s

And before that all the audio will more than likely have been digitised at some point. Either because the music is played from a digital source or the studio mixing desks are digital.

So there is precious little in an FM broadcast these days that is totally untouched by digital. And compressed format digital as well.