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Surround sound card with good ADC?

tvih

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Use case: "PC DSP Box" at a budget (made from my older computer to avoid buying the expensive miniDSP Flex to process all my audio sources). Processes main channels of a stereo/surround setup from line input, creating a subwoofer signal to a third channel and then outputting to stereo amp and the subwoofer. This of course requires a multichannel output device.

I was hoping to find a multichannel soundcard that'd also have good input quality to enable both input and output from the same device, but not having much luck. As is the DSP loop goes via a Realtek ALC892 and the noise levels are no joke - very audible from listening position. It's more from the input than output, but realistically both suck. My main computer's AS1220A chip is better, even if not great - but it's not practical. There's too much signal level loss so it's a mess changing between the computer being in active use or just as the DSP because the volume balance with the AVR-driven rear channels is way out of whack. If I had a spare amp I could use one for the rears to keep the balance better and lower the noise somewhat, but I don't at this time.

The sound card could be either USB or PCI-e. USB would be nice in that it could be used with any computer in the future, and PCI-e can sometimes get interference via the PCI-e bus.

I looked at the popular Focusrite Scarlett 2i2 given its nice quality ADC, but it's darn expensive for just the input (170+€ with postage and RCA-6.35mm mono adapters) when I'd then still need a separate output device. I also looked at all the soundcard reviews Amir had done, but not much there.

Beyond those, from what's available domestically the PCI-e Asus Strix Soar 7.1 has reasonable claimed specs and costs 94€:

Output SNR (A-weighted) (line out): 116 dB
Output SNR (A-weighted) (headphone out): 110 dB
Input SNR (A-weighted): 110 dB
THD+N 1 kHz (line out): 0.001 % (-100 dB)
THD+N 1 kHz (headphone out): 0.003 % (-90 dB)
THD+N 1 kHz input: 0.000316 % (-110 dB)
Unbalanced output: 2 Vrms (5.65 Vp-p)
Audio processor: C-Media USB2.0 6632AX High-Definition Sound Processor (Max. 384KHz / 24bit)
DAC: ESS SABRE9006A Premier 8 Channel Audio DAC

If I used the calculator right, the input SNR and THD would seem to work out to 107 dB SINAD (for sake of comparison to Amir's reviews... but then that's A-weighted), while line output is 100 dB. Somehow it seems unlikely the input SINAD would be better than the output, but that aside both are quite decent numbers. Of course that's just the usual 1 kHz, and who knows how well the real performance even lives up to the claims. There's a bunch of measurements from the "RAID PRO" (basically the same card, just comes with an external volume control) here - but since it talks about "as headphone amplifier" I assume it's using the headphone out which has worse claimed specs. There's also no line input measurements. And I don't really have the expertise to even properly evaluate all of those headphone amp measurements.

Opinions on that? Suggestions for other alternatives?
 
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MarcosCh

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I guess the Motu M4 at ca. 250eur is too much, isn't it?

Very cheap options are the Asus Xonar u7 reviewed here, but I think it only outputs 1V
Very interestingly, the sound blaster x-fi pro comes with a remote control, that I find quite unique and useful, but I have no idea about specs.
I think you can find either of these two extremely cheap used (30-40 eur, even 20 with a bit of patience)

Edit: Sorry @tvih forgot something that is clearly written on the title. "good adc". I cannot comment on that. I only have experience with the sister of the x-fi (the hd) that is my current adc and is good enough for me, but with the two above, I have no idea. Sorry
 
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tvih

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The EVGA NU Audio and the NU Audio Pro have good ADC sections.
Yeah, should've mentioned glancing at those.... specs are indeed good, but MSRP is quite up there. Hard to say about street price as no domestic retailers that would sell those here. In fact they don't seem available in Europe in general, not sure why. Even EVGA direct orders ship from Taiwan and are very expensive.
 

Doodski

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Yeah, should've mentioned glancing at those.... specs are indeed good, but MSRP is quite up there. Hard to say about street price as no domestic retailers that would sell those here. In fact they don't seem available in Europe in general, not sure why. Even EVGA direct orders ship from Taiwan and are very expensive.
Wowow the price has gone up from $249.00 to $349.00 for a NU Audio soundcard. That's absurd.
 

Doodski

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Turns out my "regular" online computer part shop said I could try the ASUS card and return it if it's not sufficient, so I pulled the trigger.
Cool. Perhaps you could send it in to ASR for a test/review? :D
 
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tvih

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Not exactly practical. Wish I could measure it myself, though, out of curiosity. But if it manages to do the I/O loop without any audible noise/distortion, that's what matters. It certainly can't do worse than the ALC892 (unless it doesn't work at all)!
 

Doodski

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Not exactly practical. Wish I could measure it myself, though, out of curiosity. But if it manages to do the I/O loop without any audible noise/distortion, that's what matters. It certainly can't do worse than the ALC892 (unless it doesn't work at all)!
Hmmz... I use Sennheiser and I have a Z690 ASUS STRIX ROG motherboard with the new USB sound circuitry onboard that is ALC4080 with Savitech SV3H712 amplifier and it sounds great. I had the ASUS STRIX Z370 before this and frankly I can't hear a difference and they both go about as loud as each other. :D I think the onboard sound has evolved to be pretty good.

I think you could do a loopback through the ADC and get some tests of your ASUS sound unit. I have never done it but there are peeps here that do it. Perhaps they could assist you.
 

Doodski

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@tvih check this link for using the ADC input for test stuff.
 

Dunring

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If you check your nearest EVGA site they sometimes have factory renewed Nu audio cards at great prices. Also creative labs has a renewed section on their regional sites and if the AE-5 will do the job, here we can get them for $79 with shipping. I prefer the AE-7, but those are almost never on sale.
 
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tvih

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Hmmz... I use Sennheiser and I have a Z690 ASUS STRIX ROG motherboard with the new USB sound circuitry onboard that is ALC4080 with Savitech SV3H712 amplifier and it sounds great. I had the ASUS STRIX Z370 before this and frankly I can't hear a difference and they both go about as loud as each other. :D I think the onboard sound has evolved to be pretty good.

I think you could do a loopback through the ADC and get some tests of your ASUS sound unit. I have never done it but there are peeps here that do it. Perhaps they could assist you.
My main motherboard is a ROG Strix B660-I. Its S1220A (also Savitech for the front output) is definitely a lot better than the ALC892 in the other computer now used for the DSP. The ALC892 can have "passable" audio output, but the input is terrible. When I was further adjusting the levels I confirmed that with the line input set to just 50% and output to 100%, effectively all of the audible noise was caused by the input.

I did somewhat test the B660-I's input by sending it a signal from my Topping DX3 Pro+, but with how small fractions we're dealing with it's not all that accurate, I reckon. Certainly the THD and noise levels I was getting according to REW should've been inaudible, but in practice there was audible interference when outputting from the speakers, even when idle ("background interference"). Regardless, for actual daily use it's more convenient to have a separate device doing the DSP loop since that way it's basically "set it and forget" regardless of which audio source I'm using. Plus like the Soar soundcard - I can't put it in my main computer since it's an ITX board with a GPU installed. It's a bit funny, I buy my first non-GPU expansion card since 2006 just months after buying an ITX motherboard - in large part because I never buy expansion cards :) Though that said, PCI-e soundcards can get interference from GPUs just like integrated chipsets can, while with the other computer it's otherwise idle with only the CPU's integrated GPU for display output, thus minimizing interference sources. Whether that's enough, I'll hopefully find out later this week.
 

AnalogSteph

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I can pretty much smell the ground loop on the input side from here. Trying to use a PC with unbalanced I/O as an external DSP box doesn't tend to work out, unbalanced audio connections and multiple IEC Class I devices just don't mix well.

But yeah, the old ALC892 is no great shakes. Specified ADC SNR is only 90 dB(A), that's definitely not enough for a passthrough DSP application outside of car audio. An ALC1200 should work out alright (some measurements in this thread), but the ALC1220 has some more to offer still. I'm not sure whether the eccentricity displayed by the Asus Xonar SE in my testing is normal for this chip, in some respects I actually liked the more predictable ALC1200 performance.

I have some ideas for how to tackle the ground loop issues:
1. Instead of using analog input, stream audio to the DSP computer digitally (preferably resampled to a constant format) and pipe it into the DSP software. This eliminates the need for ADC altogether, unless you have any analog sources to take care of. Those could still be run into the line-in if need be as they generally aren't the problem, but at least you've gotten rid of the pesky PC and the associated ground loop.
2. Tack on an external portable mixer to serve as a balanced receiver for the onboard line-in, plus custom balanced cabling to eliminate the ground loop.

System configuration, BIOS and OS are likely to require some tweaking to get power consumption down as well - the more continuously stuff runs, the more of an impact it has upon the power bill. Office boxes tend to be quite economical from the factory, hardware from the DIY realm not so much (e.g. you may have to turn on ASPM manually and such). Basically what you want is a stripped-down system with onboard graphics and a power supply that's not oversized and of good efficiency. Using Wake on LAN may be interesting, even if just to boot the system. Disabling additional onboard components OS-side may give lower power consumption than in BIOS, so try both.
 
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tvih

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Power bill in itself isn't an issue - I pay a fixed electricity cost per month. Though of course there's the "green" consideration beyond that. But yes, the computer is tweaked to run at low power. No GPU, platinum-efficiency PSU, lowered CPU voltage, etc. If I could've found a USB solution I would've used a laptop for even lower consumption.

As for the ground loop and equipment in general - it has to be analog input because the audio has to come from my AVR which can't send digital audio to the PC (or any other DSP device). I don't know about portable mixers, but sounds like it'd be another costly addition. And would having balanced connectors in that make any difference when neither computer nor AVR has them, and thus it'd be an adapter situation anyway? I also suppose that the Focusrite as input to the PC or "separate" DSP device such as the miniDSP Flex would have this same problem as well.
 

Lupin

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platinum-efficiency PSU
Totally off topic but about all PSU's run most efficient at 50% load and least efficient at 10-20% and 100% loads.
Low power systems should have low power platinum PSU so that the PSU always operates around 50% load. Most PSU's now days start at 500+W so most of the time not most efficient :);)
 
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tvih

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I know, but it's the best I can do - it's indeed 500W because it's all I have for the task. Still, better 500W platinum than 500w bronze or such :p The laptop would've been better suited for a low-power job as said, but alas.
 

AnalogSteph

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As for the ground loop and equipment in general - it has to be analog input because the audio has to come from my AVR which can't send digital audio to the PC (or any other DSP device).
What all is connected to the AVR? And I mean everything. It only takes one thing to complete a ground loop.
I don't know about portable mixers, but sounds like it'd be another costly addition.
I was thinking at minimum the likes of a Behringer Xenyx 802, which around these parts can be had for the princely sum of 55€ brand new, or a 1002 (64€), or a Mackie Mix8 (85€) or 402VLZ4 (98€).
And would having balanced connectors in that make any difference when neither computer nor AVR has them, and thus it'd be an adapter situation anyway?
Yes, if you can break a ground loop this way (when using suitable cabling). It's much like using a line isolator. Those aren't entirely free either, a Behringer HD400 alone is 26€ and with decent cables you're quickly in the 40s. A fancier model quickly costs as much as a little mixer.
I also suppose that the Focusrite as input to the PC or "separate" DSP device such as the miniDSP Flex would have this same problem as well.
The Flex sports a barrel jack for 12 V DC, so presumably comes with a typical IEC Class II wall wart. That makes things much more likely to work out (assuming the USB input is not connected).

Out of interest, which model power supply is this? 500 W and 80+ Platinum rating isn't a very common combination, only a handful of new models available to retail customers have been certified in the last decade.
 
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tvih

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AVR is connected to TV, main PC, PS3 and PS4 as sources. AVR outputs to rear channels directly, main channels to DSP PC via pre-out, DSP PC then connects to stereo amp and subwoofer. Given the digital multichannel signals as audio sources, between AVR and stereo amp is the only place to put the DSP in this scenario, other than the limited offering inside the AVR itself.

The power supply is a Super Flower Golden King 500W Platinum. "Fanciful" name, but quality hardware nevertheless.
 

AnalogSteph

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AVR is connected to TV, main PC, PS3 and PS4 as sources.
A problematic bunch in this context.
TV may be grounded e.g. via an antenna connection, or at least have substantial mains leakage current (from mains filtering).
PC is an IEC Class I device, so grounded via mains PE.
PS3 and PS4 I would suspect to have substantial mains leakage as well.

The AVR to DSP connection will need something along the lines of what I was suggesting for sure, even if it's just a decent line isolator. It is really best to leave your source setup as-is - now presumably all mains leakage is drained via the PC over HDMI, so any line isolator or balanced connection (sans shield connection) should have an easy job.
The power supply is a Super Flower Golden King 500W Platinum. "Fanciful" name, but quality hardware nevertheless.
I am well aware of the brand. It has to be the SF-500P14PE then? That was seriously fancy a decade ago, too bad they didn't measure 10% efficiency at the time. From the 20% and 50% values I would estimate 88-89 % though, which would still be a good stat today. It should be very hard to top that short of going for a PicoPSU solution. I'd only consider that if the platform is at least Haswell (complete with DDR3L and all).

How much have you gotten the system down to in idle? My office rig (i3-2120 on FSC D3161 with Q75, 2x 4 + 2x 2 GB DDR3-1333, be quiet! Pure Power 11 400W, Samsung 850 Pro 512 GB SSD, DVD, PWM-controlled 92mm Noctua and be quiet! Pure Wings 2 CPU and case fans, DVI output to 1280x1024 monitor) makes it to about 18 W, and I think that's about as good as you can expect from a system of this generation with that many RAM modules. Haswell can crack 10 W, Skylake to 9th gen even less.
 
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