Dolby 5.1 and DTS decoders

[Gabevee]

Hello all,

I am thinking of getting my home theater wired up for full surround sound. Being in this group I hope you are assuming that I make my own amplifiers. However, I do not have enough knowledge (though I could work from a schematic and parts list, hint hint) to make my own Dolby digital and/or DTS decoder. I would like to know if anyone here knows of a model I can purchase.

My only other alternative is to buy a system with it built in and just rip out the crap amplfiiers and run it to my amps. Although that may be a waste, as I read and see that there is a movement to Dolby 6.1. Center channel rear. Give me a break!!! But, it may be cool after all.

Thanks much in advance!

 

[tiroth]

Bump. I'm also looking for a quality seperate that does DD/DTS96. DAC quality is not an issue, but cost is.

Anyone have any luck with the samplerate.com people?

 

[Gabevee]

I took a look at that site and below in fine print they say they only deal with manufacturers of systems. I am just going to buy a 5.1, DTS, etc. Receiver and make power amps. It would be cheaper that way. I can always replace the crap op amp chips with high quality ones, and since I am using tube power amps, well...

I didn't even think about the fact that I would need 5 or 6 ganged potentiometers for volume control. Yikes!

Gabe

 

[MazzPotential]

Hi, Gavebee,

You're thinking my thoughts.
I've trying to compose my own dd/dts or even THX(small or EX) system.
It's not that easy to find a decent schematic of a good dd/dts decoder. Even if you can find one, it's expensive to build one that meets good standards.
I was thinking of starting with a Harman Kardon reciever , not to expensive but 96 k/bitrate at 24 bits wide pre-outs, combined with some, yet to build own power amps. And take it from there?

If got some power-amp schematics if you're interested,

Mazz.

 

[tiroth]

Schematics are actually the easy part; the hard part is the application code. None of the surround-sound DSP chips that I am aware of are closed systems; they require an application code download at boot.

 

[Gabevee]

Thanks Mazz,

I am thinking of making four 300B tube SE amps for the five surrounds and center channel, and my p-p 15 WPC for the sub woofer. I never need more than those put out as they are now in stereo.

Otherwise, a MOSFET output p-p design I have been working on for some time.

But I wouldn't mind taking a look at your shcmeatics.

Thanks!

 

[Gabevee]

Jeepers. I must be suffering from dyslexia of the fingers!

I meant schematics, not shcmeatics.


Later!

 

[MazzPotential]

Schematics ?

Geavebee,

If you could give a direction what kind of amplifier type you want to build. Are you looking for Tube schematics.
I've got several schematics ranging from 10 W to 100 W based on the EL34 tube, avail in three mode types : Ultralineair, Penthode and triode mode ?
If you're looking for SS schematics just give me some specs and we can discuss best maching schematics.

Mazz.

 

[blu_line]

I do not think it is worthwhile making your own DTS decoder.
Buy a good DVD player with 5.1 channel out and make a good pre- and power amp.

Probably, with good results, you could upgrade your DVD player by using other DAC's.

And if you are realy in to it, make 6 digital outputs and do the DA, pre- and power amp your self. Then you have the advantage of the decoder after all.

For those who are really not convinced, Hiteker uses a commercially available DTS decoder which could be used.

http://www.dvd-wizards.com/darrenk/ES4408.pdf

grtz

Simon

 

[promitheus]

Making your own decoder is not the easiest thing to do for a lot of reasons. As stated above there isn´t so much information on the chips. It´s better to buy somehting ready and use your own amps.

 

[tvi]

<b>Gabevee</b>
<i><font color="#804000">My only other alternative is to buy a system with it built in and just rip out the crap amplfiiers and run it to my amps. Although that may be a waste, as I read and see that there is a movement to Dolby 6.1. Center channel rear. Give me a break!!! But, it may be cool after all</font>"</i>
<hr width="95%" align=center>

You might want to look at the <a href="http://www.outlawaudio.com/news/news_mar_950.html">outlaw audio Model 950</a>, no amps to pull out
Don't know if you consider their prices cheap "<font color=#808080>Model 950 standard pricing: $ 899</font>"

<img src="http://www.outlawaudio.com/images/950-inside.jpg">


Regards
James

 

[Gabevee]

Hi,

Thanks for the info. At least there is someone who is making the decoders. But you are right. $899 is not worth it, not when I can get a complete receiver for $200. And.. I can make anything sound great.

Thanks!

Gabe

 

[Helix]

i think i can see some electrolitics on the inputs!, yuck

It says that has taken many engineers many man years to design it? slow workers methinks


it has taken me a less then month to design a 5.1 preamp and selectors for digital/analog inputs/outputs and volume control! all i need is to bolt on a DAC or a decoder if i can get one! i admit i have used quite a few relays but at least they are better then those yukky CMOS/transistor switches for audio signal paths

 

[Bose(o)]

DTS is the way to go. DTS 5.1 has more discrete channels and a higher bit rate than Dolby Digital. Now, DTS Neo 6.1 or something like that may not be needed for some rooms. My family room {current home theatre area} will not permit DTS 6.1 for, the sixth speaker is in behind. If you pick up a Denon receiver with 7.1 then, I would be fine. I have room to hang side speakers and the rears will fit nicely. I have only rented two DVDs that make use of DTS 6.1 and would wait If I were you until it is more commonly used unless, you opt. for the 7.1 receiver. I only know of the 7.1 receiver by Denon maybe Onkyo as well...

 

[jgwinner]

Interesting thread

I've got the same issues - we're going 'backwards' in our Home Theater, we got a Hitachi LCOS video projector for Christmas. Currently, I'm using my old Technics SA-500 to drive the speakers, from my Sound Blaster Live! (NOT Value) and my DVD player in my PC. (ATI 8500DV). Scream! <G>

I don't know if any 'real' 5.1 decders are available in the PC, although it does have SPDIF out; the PC environment is so noisy electrically, I really would prefer to move the digital sound out of it to a seperate decoder. The SoundBlaster Audigy looks good, but again I don't like the idea of audio leaving the PC, just digital.

I've been looking at DIY'ing some Electrostatic speakers, so I'd be looking for a solid state or tube amp to drive those, I'd want just the digital decoder and possibly pre-amp. Most home theater systems have the amps built in, which I wouldn't want to use (not sure if they would drive the electrostatics).

Eventually, I want to get a DVD player, but my PC has DVI out, and the projector has DVI in. I'm waiting until I get a DVD player that takes pure DVI in.

A bit rambling, I guess the bottom line is I'm looking for the same thing <G>.

 

[MazzPotential]

jgwinner,

There are good quality soundcards that incorparate excellent 5.1 decoding. e.g. the "DMX 6fire from Terratec" 24bit/ 96 khz res.
Bit expencive though. Europe $200.
An other solutions is to buy a good quality low power amp. e.g. a Harmon Kardon. One of it's amp's has 5 x 40W which is enough for small livingrooms, but has excellent decoding capabilities. 24bit/ 96khz Plus 6 pre-ins and 6 pre-outs. This allows you to expand the system. If your hunger for more power grows you can buy 2,3 hell even 6 seperate high-end/high power amps to connect to you HH am, and still have great decoding.

You're talking about building your own ESL's and which amp to buy. Well, don't worry about the amp.
First of all the ESL do not give you amp the complex loads simular to conventional electromagnetic speakers.
Second, The ESL needs a step-up transformer to meet the 3kV up to even 15 kVs to drive you ESL. So output wise (Peak Voltage) any amp will do.

Mazz.

 

[Electro]

Sound cards do put out distortion but this only when analog hook up from the CD drive is used. A/V receivers has this problem too.

My sound card (Soundblaster LIVE! 5.1 channel) doesn't put any distortion. Only the fans in my computer gives me a noisy sound environment.

I don't mind paying a little over $250 on a sound card that gives me a gold plated I/O slot and better sound for my next computer. My next computer will be using AMD's new processors (hammer series). Though I have to spray paint a gold color on the back of the computer to match the sound card.

On the outlaw audio Model 950. Anybody can desolder components and replace them with better components such as mylar or tantalum capacitors for the inputs.

Below is an interesting link that shows the distortion analysis of different converters.
http://www.pcavtech.com/soundcards/ADA1000/index.htm

 

[Neopsp]

Hi all.

I have been looking for a standalone dolby digital and DTS decoder myself. I really think there is a market for just that. No preamp, just the decoder. Many of us have our own special preamps and amps but want the decoder as an extra. I have emailed a few companies and told them this. What do you guys think about the Sound blaster Extigy? It only has dolby though
Thanx
Neopsp

 

[Sawzall]

Advancing the art..

I have seen several systems now that are implementing more and more of the decoding in software vs. hardware. While this is mostly in the commerical sector, it is growing in the consumer market too.

These systems are often based on FPGA type chips that offer the ability to "download" the newest and greatest codec. What I propose that makers should do is this:

1. Build a system that allows the codec to be soft loaded in to the magic decoder ring built into the system. (realizing that it requires a pretty smart and fast decoder ring..)

2. Have the actual optimized codec come with the source. So if the recording is done with Supersystem 1.2, it has the "executable" part of the codec as the first track.

3. As part of playing this recording, first the player reads the codec, loads it up, then plays the music (or whatever the info is).

The good part of this is that we could get out of this hardware cycle we are all caught in. Just look at the alphabit soup of codecs, even on the consumer market - MP3, WMA, Real, Dolby in about 4 flavors, DTS in several flavors, matrix, descrete, etc. Codecs based on psychoacustics like AAC+ and PAC are just now coming and promise to get much better.

The other good thing is that this would allow the producers of the music to decide on what made their music sound the best. It would also mean that we would end up with less out of date hardware - and you could take a chance on "early adoption" since it would be less likely that we would end up with a Betamax type doorstop.

The computer world recognized they had to break this up, thus XML where the data is split from say the data definitions.

I think this would a smarter way to go.

(Or quite possibly, I have lost my mind.)

 

[tiroth]

Some manufacturers already do this. The problems I see:

- 90% of consumers won't hook their DVD player up to their computer to upgrade it, because of ignorance, apathy, or cost of the upgrade

- If adding the I/O interface adds $4 to the cost of the unit, it is probably too much for the mid-fi market to absorb. Hi-end ($$$) is different.

- Providing code updates requires work on manufacturer's parts, and could undercut sales of newer units.