Thread: For those who want true 5.1 Dolby Digital and DTS

Originally Posted by Will Albers

but is the onboard spdif output of the same quality as the Audigy/Extigy?

I hope you don't think this is a good thing...

Originally Posted by Defiler

I hope you don't think this is a good thing...

Im confused, whats a good thing?

I have noticed the analog output of my onboard sound card is awful. It really seems to merge bass response into a certian range of frequencies making everything sound the same.

My question comes down to the SPDIF output. In a perfect world, the digital out would be unchanged and left to the outboard DSP. I question if this is infact true or if the digital signal output is different between the audigy/extigy and the onboard sound.

Originally Posted by fonseca

Ugh, I'm sick of messing with this converter. They must have stuck whatever sticker they had lying around on the AC/DC adapter. It puts out 9.3v, not 6.

I built a converter as shown in the diagram below, and it works, but only for about 1 second. Although it works perfecly when the coaxial signal is coming from a home theatre component's output. I can only conclude that Via's signal is pathetically weak.

I'm going to replace the 7806 with a 7809. I don't think think the cap is the problem, that should be enough for such a small draw. But if that fails then I'll either try an LM317 and a variable resistor, or give up and get reamed by Radio Shack for their $31 DC adapter. If anyone sees a problem with my simple diagram, let me know. I don't think a cap is needed before the regulator.

Edit: And BTW, the 7806 gets very hot. You need a heatsink.

As strange as this may be i found the best way to power this converter was off the PSU 12v rail with a 12v-5v radioshack convertor stepping it down to 5v. There seems to be some weird floating ground or somthing.

Also i think vias SPDIF signal is weak as hell.

Personally i tried other convertors and never got anywhere with them. Your milage may vary.

Originally Posted by scfountain

My amp and D/A converter will be hooked to my SDC so the entire car multimedia system will power up/down together.

Your setup is similar to mine. Although I'm not using a glass fiber optical cable since I needed a tight bending radius in several spots and didn't want to chance it.

My amp, ADD51T and SDC all get their turn on signal from the stock radio harness accessory wire. I have my alarm hooked to that, so I get run time of up to 10 minutes (or until a door is opened) when I first cut off the car, and I also use a latched accessory output channel to turn the entire system on and off for however long I want via remote, whether the car is running or not.

Originally Posted by Will Albers

My question comes down to the SPDIF output. In a perfect world, the digital out would be unchanged and left to the outboard DSP. I question if this is infact true or if the digital signal output is different between the audigy/extigy and the onboard sound.

I have tested this myself on my home theatre system, comparing the onboard SPDIF to that of an Audigy, with a 16 bit source. I can't say that the sound is 100% identical, unless my ears are lying to me, however I also can't say that one sounds significantly worse than the other, just that there are some differences in tone. In a perfect world, you wouldn't hear any differences between SPDIF cables either, but I know for a fact you can.

I am satisfied with the onboard SPDIF sound quality. IMO it's comparable to my Audigy, and not even close to the noisy onboard analog out. It provides better sound than the rest of my car system can take advantage of, so it's not the weak link.

Originally Posted by antimatter

There seems to be some weird floating ground or somthing.

Dernit. I may have to break down and buy one. If I open it up and see a 7805 in there I'm going to be irked, although that would mean I did something wrong wiring mine.

I'll be thrilled to finally have digital output. I hate having so many redundant equalizers and volume controls, even though some are linked. Windows, Vinyl Deck, Winamp and AC3 Filter just to name a few, and then there are apps and codecs with their own internal controls.

I don't know if the quality of SPDIF is the same as Audigy or not. I just started building this from the ground up, I haven't made it to the experimental stage yet. I'm still in the process of purchasing all the gear.

So Far:
VoomPC mini-itx case
I-Base MB896F
Crucial 1GB DDR2-533
Pentium M 740 1.73 Ghz 533FSB
Intel 2915 a/b/g mini-pci wireless card
Audiobahn ADD51T
Alpine MRV-F545 amplifier
Xenarc 700TSV
ATP SD USB card reader (for in-dash SD slot)
USB Memory Stick DUO reader (for in-dash memory stick duo slot)
CarPC v2.5 Platinum SDC
PW200-V DC-DC PSU w/ P4 Mod
Pioneer DVR-K05 USB Slimline slot load DVD+/-RW
...and various other accessories.

Originally Posted by fonseca

Anyone considering the ADD51T should be ready to buy a coax-optical converter, I had no luck gettig it to recognize coax input from both onboard and pci soundcards, although it worked fine connected to a home DVD player.

My ADD51T is connected to a Blaupunkt DVD player in my SUV via a SPDIF coaxial cable and works perfectly. Try changing the cable before settling on a coax/optical convertor.

That's what I thought the problem was at first, even though it worked with other components using a standard non-digital RCA cable (which is usually the case when the cable is only 3' long). But I made a 75 ohm cable with RG6 and true 75 ohm plugs, and no luck. I even bought (and later returned) a commercial spdif cable which claimed--falsely--to be 75 ohm. The cable might have been, but not with the massive RCA plugs on each end.

The problem is the low power output from the Via board, the ADD51T won't recognize it, although other more sensitive components will, such as my Livedrive or component receiver.

I also got the converter working on 8v power, with a 7808 and a .1uF cap on both the input and output. Interestingly, I did get it to work on 5v and 6v as well, but only when the converter was connected to my home theatre receiver's coax out, the minute it's unplugged the LED cuts out, and won't turn on when connected to the m10k. I'm not worried about running it on 8v since the AC/DC adapter put out 9.3v, even though it said 6v. And the 7808 barely gets warm, unlike the last one.

Digital sound was worth the effort, though. The sound quality in my car is excellent, I'm ging to have to ditch a lot of my mp3s for flac, a lot of my 192k stuff is no longer satisfactory. Now I'm craving a speaker upgrade too. Components would be nice.

It's going to take a lot of tweaking though. I had to boost the volume level for movies and music playing in media player classic, they were much louder in Winamp and PowerDVD. Must be the fault of ffdshow. Preamp and EQ settings still work in Winamp, ffdshow and ac3filter (which I am no longer using, redundant), but I've disabled them for now to see how the Audiobahn unit does on its own. It has decent adjustability, but the lack of a full-fledged EQ is annoying. The bass and treble controls adjust 100hz and 10khz, respectively. So I'll probably end up needing the EQ in Winamp.

I haven't experimented with 24 bit audio yet, but the ADD51T supports it.

Originally Posted by fonseca

I haven't experimented with 24 bit audio yet, but the ADD51T supports it.

Start looking into Bit Perfect DTS audio. I think there is a plug-in to do so in Media Player Classic. It's the shizzle if you haven't heard it before.

Here are some files you can DL and try.

http://www.sr.se/multikanal/english/e_index.stm

Originally Posted by antimatter

That is the same one i had. I tried upgrading to the M-Audio C02 and am having problems and now i am trying the M-Audio Transit.

That cheap unit worked great for me except when i stepped on the brakes the sound would cut out for a sec. I think it was my wiring but as of today i haven't been able to figure it out.

Any updates brotha?