Audio interface : does it really affect quality ?

[bmrzycki]

Yes, I was totally reluctant to recommend it, because I agree, so many of these claims are clearly based on dubious science. However, I feel that the OP might be the discerning and serious engineer that an appreciate a next-level product like The Wire.

are you?

I'm just a crap hobbyist. I'll stick to crap parts that don't make me special because I own them. Maybe one day I'll be cool and spend $10k on a power cable. Until then I'll just have to settle for one of these. https://www.walmart.com/ip/Insten-INSTE ... s/36215826

[Googly Smythe]

Best thread for a long time. Love it.

[liquidsound]

A good pair of Q-tips.
Done.

[BertKoor]

I think it's a good question though, and it needs a proper answer.

I have a Virus TI2, while I would like to connect it within an audio interface (Lexicon Alpha)

May I ask why? If you connect it over USB, you get a direct copy of the digital audio without any loss.

How does audio interface affect sound ?

The answer is to look at the technical specifications of your interface:

Line Inputs
Frequency Response: +0, −0.5 dB 20 Hz - 20 kHz, ref. 1kHz
THD+N: <.009% A/D, 20 Hz - 20 kHz

Dynamic Range:
A/D (24 Bit) 100 dB typical, A-weighted, 20 Hz - 20 kHz
D/A (24 Bit) 100 dB typical, A-weighted, 20 Hz - 20 kHz
A/D/A (24 Bit) 97 dB typical, A-weighted, 20 Hz - 20 kHz

Maybe for illustration compare it with the specs of an interface that costs several times more (the RME BabyFace)

Frequency response AD, -0.5 dB: 50 Hz – 20.9 kHz (sf 44.1 kHz)
Dynamic range AD: 108 dB RMS unweighted, 111 dBA
Dynamic range DA: 112 dB RMS unweighted, 115 dBA
THD+N AD: < -98 dB (< 0.0012 %)
THD+N DA: < -100 dB (< 0.001%)

The frequency response ought to be flat. Since perfectly flat does not exist, it is only flat within certain limits:
* between 20Hz and 20kHz (which is the regular audible range, no surprise there)
* there are no peaks in the spectrum but there can be attennuations of -0.5dB (usually in the extreme low & high frequencies)

Dynamic range is basically the difference in loudness between the loudest possible signal and the softest (before it drowns into background noise)

THD (total harmonic distortion) should be zero for perfection. These are frequencies present in the output of the component that were not present in the input. In normal words: distortion.

Is it audible ? Can we hear the loss of quality ? Or do we loss about 2-3 purcents of the sound ?

For reference: compact disks sound good. Right?
Being 16bit their dynamic range is limited to about 96dB and this also limits THD to something like 0.01%. So your "cheap" interface doesn't have the dynamic range that the expensice RME product has, but if you press it's recordings to CD then "something" (one single bit of resolution) is lost.

Feels a lot better now, right?

[Mister Natural]

Yeah, not so sure, this is really going to depend on the quality of your interconnects, no? I mean, ok, if you're using a high quality USB cable like the audioquest diamond, maybe...

I'm gonna have to call BS on the idea that "hi-quality" digital cables sound superior to common Sam's Club digital cables. The D/A converters inside the interface don't have to convert anything and passes the digital signal along to the ASIO converter inside your computer. I know that there has long been conversation that better copper sounds superior to cheap copper within cables but I respectfully disagree. Copper is copper and bits are bits.
The only qualifier I'd recommend is if you're gigging night after night. Plugging and unplugging, stepping on this line or dropping it. In such a case; you'd want to have heavy-duty cable jacketing and strong terminations.
peace

[ghettosynth]

Yeah, not so sure, this is really going to depend on the quality of your interconnects, no? I mean, ok, if you're using a high quality USB cable like the audioquest diamond, maybe...

I'm gonna have to call BS on the idea that "hi-quality" digital cables sound superior to common Sam's Club digital cables. The D/A converters inside the interface don't have to convert anything and passes the digital signal along to the ASIO converter inside your computer. I know that there has long been conversation that better copper sounds superior to cheap copper within cables but I respectfully disagree. Copper is copper and bits are bits.
The only qualifier I'd recommend is if you're gigging night after night. Plugging and unplugging, stepping on this line or dropping it. In such a case; you'd want to have heavy-duty cable jacketing and strong terminations.
peace

http://www.tnt-audio.com/accessories/di ... les_e.html

[NotreDame]

Thanks a lot Bertkoor !

But here is a strange thing : I planned to buy a Roland UA-55 Quad Capture.

But when I read its specs, the frequency response is : +0, -2 db !!

My lexicon Alpha wich cost me nearly 1 quarter of the UA-55 price (60 dollars vs 220 dollars)has only -0,5 db.

Did I miss something or does it really mean that the Alpha lexicon can provide a far more flat sound than the Roland one ?

[BertKoor]

Possibly the freq response plot looks something like this:


I'd rather have the card with the red curve because of the ripples you see at the green curve.

So somewhere in the 20Hz-20kHz range there is a cutoff of -2dB, but not in a region where it's that important. The figures say nothing about the squiggliness of the lines, only within what box they fall.

[bmrzycki]

I own a UA-55 and love it. Best interface I've owned out of 4-5 or so. And yes, I have used the line and mic inputs.

[ghettosynth]

Thanks a lot Bertkoor !

But here is a strange thing : I planned to buy a Roland UA-55 Quad Capture.

But when I read its specs, the frequency response is : +0, -2 db !!

Woah! That's a lot of variation!

[aciddose]

[ghettosynth]

Well, you get what you pay for, amiright?

[Mister Natural]

[ontol]

Expensive cabling is all well and good, but to squeeze even more out of those high-end cables, you gotta get serious:

http://www.machinadynamica.com/machina31.htm

[ghettosynth]

Expensive cabling is all well and good, but to squeeze even more out of those high-end cables, you gotta get serious:

http://www.machinadynamica.com/machina31.htm

Well, I suppose, if you're on a budget perhaps. These do a much better job.

http://www.shakti-innovations.com/product/shakti-stone/