General Forum

Re: Any new BeoLab in the near future?

koning — Mon, 18 May 2009 14:02:23 GMT

Deleted

Re: Any new BeoLab in the near future?

tournedos — Thu, 05 Feb 2009 03:54:42 GMT

I'll revive this topic, since I just took a look at what I'm supposed to be studying

All this phantom channel stuff is, obviously, pretty much old news at the time you can start buying them in shops:

http://www.acoustics.hut.fi/research/cat/vbap/

Re: Any new BeoLab in the near future?

Mr10Percent — Sun, 01 Feb 2009 20:55:45 GMT

Just as a stupid thought.....

Could one simply install a Powerlink Y-Splitter, and connect the Centre Channel powerlink to the splitter, then onto the second powerlink input on a pair of BL5's?

The dual signals (assuming no clasing of signals) would be mixed in the BL5's powerlink board before going to the DSP. The Beovision would still do the mixing and the timing adjustments.

Just a silly thought for all those wishing to experiment.

10%

Re: Any new BeoLab in the near future?

Alex — Sun, 01 Feb 2009 15:18:41 GMT

No, all channels should arrive at the listener at the same time, hence why surround sound decoders have options to set speaker distances to compensate for speaker placement.

Re: Any new BeoLab in the near future?

wonderfulelectric — Sun, 01 Feb 2009 15:15:34 GMT

Ever thought maybe the phantom centre channel will need to arrive to the listener first before the left and right to create a more realistic centre channel reproduction?

Re: Any new BeoLab in the near future?

soundproof — Fri, 30 Jan 2009 05:26:31 GMT

Thanks, Tournedos. Yes, controlling the centre-channel signal is not very difficult, and it should be possible to include this in an upgrade.

BTW - always be careful with using "not rocket science." Here's a true story. A manager from a leading European telecommunications company was in Russia, where they were going to enter into a venture establishing a communications link that included satellites. The manager said "Well, after all, this isn't rocket science."
A voice from the audience, in accented English, responded: "We're all rocket scientists, and you're right, this is not rocket science."

Re: Any new BeoLab in the near future?

tournedos — Fri, 30 Jan 2009 05:19:40 GMT

soundproof:

Ah, I get it. You're thinking of passive systems that just pipe the signal on? Today's home theatre processors perform quite a lot of calculations on the signal, particularly those that perform measurements of the room, in order to achieve the best possible sound, with an absence of room nodes, phase-outs, etc. And that takes a lot of processing, but with good results.

I understand and appreciate all that, my focus was still just on the phantom center channel. As far as I can see, the basic "processing" is this:

take a center channel sample
shift it to right one bit (to divide by 2)
add it to both L and R

...and that's it. This part in digital domain could be wired on a euro sized PCB with 74 series TTL chips from the 70s with no DSP at all, and an analogue implementation would struggle to fill a small breadboard

In practice, I would probably want an adjustable delay to virtually move the "center speaker" back and forth and a level adjustment, but it's still not rocket science. Sorry if I mislead you to elaborate, I always enjoy reading your posts (and will follow those links when I have better time, I can't call myself educated on home theatre specifics).

Re: Any new BeoLab in the near future?

soundproof — Fri, 30 Jan 2009 03:15:07 GMT

Ah, I get it. You're thinking of passive systems that just pipe the signal on? Today's home theatre processors perform quite a lot of calculations on the signal, particularly those that perform measurements of the room, in order to achieve the best possible sound, with an absence of room nodes, phase-outs, etc. And that takes a lot of processing, but with good results.

Here's what Jens Abildgaard Pedersen, one of the co-inventors of BL5, has been working on since he left B&O. He did the low-frequency room calibration, and was in charge of the project:

http://www.aes.org/sections/uk/meetings/a0611.html

Re: Any new BeoLab in the near future?

Alex — Fri, 30 Jan 2009 01:46:03 GMT

Agreed! It's hardly processing.

Having said that, if it is done by the DSP stage, and two 24 bit signals need to be converted and the output converters run at 24 bit depth, some processing will need to go on to reduce the volume etc...

Still not exactly a huge task...

Re: Any new BeoLab in the near future?

soundproof — Thu, 29 Jan 2009 19:39:50 GMT

Well, we do speak of surround sound processing, and the hardware is called surround sound processors ... it's not the number of speakers that is being referred to, but the work performed by processors applying algorithms to digital files, before these are converted to analog signals that are passed to the speakers.

http://www.hometheaterhifi.com/masterindex_surround_processors.html

Re: Any new BeoLab in the near future?

tournedos — Thu, 29 Jan 2009 19:32:42 GMT

Hmm, looks like somebody has taken the phantom whatever idea further and gotten away with the three speakers per setup idea... sounds familiar...

Seriously, do we have to call summing and subtracting "processing"?

Re: Any new BeoLab in the near future?

soundproof — Thu, 29 Jan 2009 17:06:22 GMT

Wonderfulelectric is correct here. Goldmund doesn't believe in the centre channel - which is kind of a special statement, as long as movies are mixed with one. But their reasoning makes sense - they feel the centre channel, even with a proper movie projection screen that is perforated to allow the sound to bleed through, is just not right, and that their solution (with a phantom centre) is better.

A nice run-through of the principle here: http://www.goldmund.com/technology/th3/

As stated above, this is an area where I feel B&O missed the boat, as the acoustic lenses could have created some buzz for an alternative solution from the company. Goldmund has spent quite some time working with the sound processing, in order to achieve perfect time alignment of all the drivers in their setup, and in order to avoid phase distortions.

Goldmund's principle is called TH3 (THEATRE3) - the BL5s can emulate the same, as they have the subwoofer/woofer built-in, and can generate a phantom centre, with perfect timing and phase alignment - though not with a B&O surround processor. :

Unfortunately, to my eyes, Goldmund's speakers look like something you'd find in a gym, with weights.

Goldmund's side and rear surrounds are more conventional than what's shown in the sketch, but they are always correctly placed, up on the wall.

Re: Any new BeoLab in the near future?

wonderfulelectric — Thu, 29 Jan 2009 14:17:40 GMT

Alex:

The centre channel mix at the cinema can quite easily be mixed into the output from the main speakers creating a 'phantom' centre channel. I'm not sure how Goldmund can 'build in a centre to both the left and right channels', isn't that just called mixing the signals together?

For the Goldmunds, there literally are centre channels built into the L&R channels. So instead of one centre channel, you have 2. Meaning you have 2 speakers for each side.

Re: Any new BeoLab in the near future?

koning — Thu, 29 Jan 2009 04:56:29 GMT

Would it be the same surround processor as in the BV7-32

Re: Any new BeoLab in the near future?

Dave — Thu, 29 Jan 2009 01:20:08 GMT

Well the 40" version will have a surround processor...