Poor man's PC based home theater setup

[nqa3]

figured I could share this now since I got the last spare of Creative SB X7

- PC => (USB; 5.1) Creative SoundBlaster X7 as DAC => NCore NC122MP poweramps from audiophonics => speakers.
- TV => (Optical; AC3) X7 as DAC => ..

This is meant to be a low cost / high quality home theater, not that I'm capable of measuring (haven't done room correction since mic costs money).


The power amps have flat responses, the X7 has very low noise on spec as DAC, and no complication with AVR or HDMI stuff. X7 is the only thing I found that could decode Dolby from TV's optical out with 5.1 preouts and mixing PC output with no delay and not costing thousands. It's been dead for years of course, with no replacement on market.

On PC it needs Equalizer APO to reduce gain by -20dB or it'd wake up all neighbors, while SPDIF volume is reduced in X7 independently (with night dynamic range for Dobly decoding).

It doesn't do lossless Dobly audio or anything more than 5.1, but good enough for TV streaming apps. PC is optional when watching TV, but I do need my phone or a wireless keyboard for volume control.

Other than that, I'm expecting the setup to last another 5 or 10 years, and could pick a commercial TV as the next screen if they remove optical audio from home TVs.

 

[NotInYourHead]

Interesting - the Creative X7 also doubles as a 100W stereo amplifier with a TPA3116 chipset. It still costs $200+ on eBay from what I'm seeing.

 

[john61ct]

Crazy that such a useful combination of features just disappears off the market.

Surely must exist on Ali or at least Taobao

 

[john61ct]

OK, trying to isolate what is "unique" here. Assume power amp and HPamp not needed, AVP/AVR not wanted.

If I don't want to keep a PC in my audio system full-time, the Creative X7 would allow digital input direct from TV, decode and output via 6x analog RCA channels.

Is that what's otherwise unobtainium (#1)?

Of course, if DO keep a PC in my audio system, lots of generic Windows software can now decode 5.1 Dolby Digital, right?

I already have multi-channel DAC analog output from the PC, so no need for the X7, but I can see that saving a lot of money, is that #2 ?

If I wanted to output the decoded 5.1 digitally, where else would be useful to send it?

 

[nqa3]

#1, Yes. The unique part is just the AC3 / Dobly surround audio decoding + preouts.
AC3 is licensed, so the alternative is either AVR with 5.1 preouts (expensive, less reliable quality from what I read), or AVP (super expensive).

Software / PC / raspberry pi can decode them for free - I already tried a sound card with optical input from TV => (in AC3; sound like noise) set up "listen to device" => make a DirectSound graph to decode AC3. It worked, but 1-2s latency was unacceptable and there is no option for my TV to delay for optical audio.

The other benefit is that it's a full sound card, so PC can output surround sound by USB, something I read isn't available for most AVPs (whose USB only takes stereo). The only use I have for this is to run Dobly 5.1 upmix in Equalizer APO for music playing, which AVR already does.

 

[jbl590]

This is cool, never heard of this soundblaster or any soundcard being used this way before.

So this just connects to pc via USB? As in I could use any laptop?

Am I right that with this you never have to switch audio inputs to listen to tv audio or computer audio, both are always live?

Are we missing some of the picture here? I see two amps, perhaps they are stereo, that's 4 channels of amplification but you have 5.1? What's powering the center?

 

[aqd]

This is cool, never heard of this soundblaster or any soundcard being used this way before.

So this just connects to pc via USB? As in I could use any laptop?

Am I right that with this you never have to switch audio inputs to listen to tv audio or computer audio, both are always live?

Are we missing some of the picture here? I see two amps, perhaps they are stereo, that's 4 channels of amplification but you have 5.1? What's powering the center?

Yep, it appears on Windows as an ordinary 5.1 sound card, except with more volume controls for SPDIF-in etc.

All inputs are always live yes.

I'm only using 4 channels, not 5.1, because ncore amps cost a fortune and I don't want to spend that just for a center...

X7 has an android app to toggle speakers. For PC audio I use EqualizerAPO for dobly upmix, gain and EQ. X7 has built-in EQ too and other features.

 

[Mort]

I love that little Gussin mini rack!

 

[jbl590]

How do the ncore amps compare to tpa3255? I know they're many times the price of say a a07 max, but I'm not sure they're many times the performance. Are they?

A $50 amp like the a07 max is perfectly fine for HT use as a center.

I'm looking to move up from an a07 though so I can understand why that might not be enough for you, when I really push my jbl 590's really loud with it the weaknesses of the amp shows with music but not so much with movies. For movies it's quite good.

 

[aqd]

https://www.audiophonics.fr/en/power-amplifiers-c-6306.html tpa3255 250w cost almost the same as my ncore 125w.

 

[john61ct]

I love that little Gussin mini rack!

Gussin?

 

[Mort]

Gussin?

KGUSS on Amazon.

 

[john61ct]

Very different aesthetic from the pic you were commenting to.

I'm thinking more like this https://mini-rack.jeffgeerling.com/#standard but I like wood for shelves