http://www.audiostream.com/content/usb-audio-gremlins-exposed-beyond-1s-and-0s-ifi-audio#ZsjTLbVsfev0s4J6.97
 
 
1. Bits are really just Bits?
1.1 Background
A common sentiment heard in the context of digital audio is that ‘Bits are Bits’ and as long as data makes it from A to B, different or ‘premium’ cables and other ‘tweaks’ cannot have any effect in the physical realm and are purely imaginary.
While this view has long been debunked, where SPDIF and AES-EBU connections are concerned (not least by Stereophile and others), it is often considered a tenet of faith for USB audio - especially asynchronous USB Audio - that ‘Bits are Bits’ and any differences arising from cables, operating system tweaks and other items are purely imaginary (delusionary?).
Yet, just as differences in SPDIF Cables and/or sources, as well as DACs (and their combinations), can be shown to produce not just audible but reliably measurable differences, USB audio is subject to its own set of limitations and problems.

more.......

and this device......
 
http://www.musicdirect.com/p-364758-ifi-ipurifier-2-inline-usb-audio-conditioner.aspx
 
 
discuss?
 

The first article is interesting. I am not sure about the product at first glance though, especially when it mentions "re-clocking, regenerating" and "eliminating jitter." That is just first reaction, but the A/I clock is where the jitter comes from, and this product just seems to be feeding the same clock anyway. That product in particular is a tough pill to swallow, especially without a means to quantify real-world results.

batsbrew
and this device......
 
http://www.musicdirect.com/p-364758-ifi-ipurifier-2-inline-usb-audio-conditioner.aspx
 
 
discuss?

If that device, inserted between particular audio interface and computer, produce ANY difference in audio, the system has severe problems which should be solved properly (I mean without such devices).
 
In the first article everything is right... except all that should not happened in correctly build system.
 
All that is like ECC RAM. Does it make sense under very special conditions? Yes. Is it currently used in any "normal" computer? No. All digital connections without delivery check can produce "wrong" bits. But almost all connections within a computer have no checks and one single wrong bit there normally produce famous "blue screen".
 
In reality it either "works" or "crashes". In the second case we can install PSU, make shields, reposition cables/monitor/mouse, tweak clocks for CPU/RAM in BIOS, etc. And we can get "positive" results from such operations. But that is simply not the right way to go.
 
Audiophiles, poisoned by "hi quality super cables" (in place of simply working), probably will continue with super HDMI, super USB, super Ethernet. But bits ARE bits. If you have installed crappy switch, you can have problems switching the light in your room. But if something switch it correctly, do you need "digital noise filtering, 220Hz component eliminator with galvanic separation between switching circuit and power wires" there? In case the answer is yes, mentioned device is for you
 

mettelus
That product in particular is a tough pill to swallow, especially without a means to quantify real-world results.

oh, i read a ton of reviews,
seems to work fine for the majority.
you can google the reviews

Having formerly worked as an engineer with communication protocols, I get peeved when I sense a lack of accuracy when describing such... Too many hours coding to the wrong specification can do that to you...
 

As far back as early 2001, computer-based audio with asynchronous USB audio proved it was possible to outperform SPDIF and/or AES-EBU based ‘cookie cutter designed’ systems.
Read more at http://www.audiostream.co...io#i0bBfzyOWF1WAcyW.99

 
This is what's called blowing smoke up people's...nevermind
 
I'll take a synchronous protocol like AES3/SPDIF/Toslink over an asynchronous polling protocol like USB any day.
 

It must be understood that USB audio devices (and USB video streaming) have much stronger requirements for USB hardware and software layers than any other USB devices, such as printers, hard drives or flash drives.
Read more at http://www.audiostream.co...io#i0bBfzyOWF1WAcyW.99

 
Heh, you transfer audio data asynchronously (USB) at regular intervals - sort of a noncommittal synchronicity termed 'isochronous', if it can be described that way. It almost is, but it just ain't synchronous. It can never be as accurate as a synchronous protocol.
 
The rest of the article goes on a bla-bla about signal quality, which can affect anything on the USB bus. It's simply more apparent with audio - if it is at all.
 
Bits are bits.
 

Really the response to any people who want to sell crap like that is "Can you show me on a scope?". We can measure differences in audio we can't hear, so if a given device actually changes something, it'll show up on a test with an AudioPrecision, even if the results aren't audible. So whenever people start claiming crap like this my only response is that I want to see the AP readouts. Show me the difference. If you can't, then I'm calling BS.
 
As a practical matter all of the theorycrafting and complaining they do about USB and the like shouldn't matter in a properly implemented device because you keep the various bits of your sound chain separate. Ya, it could potentially induce noise, just like a power connector could induce noise. However when you design things properly, it isn't an issue.

What's in the box?
 
There are no details about what they're actually "doing" to the digital signal.
 
blowing smoke - yep.  
 
I agree with Super G - I've done a lot of work to an incomplete or incorrect spec as well.  doesn't mean work wasn't done - it just didn't produce the REAL desired results!
 
 

Some newest generation motherboards have a pair of "clean power" USB ports specifically for connecting A/D D/A units (audio interfaces).
My latest motherboard has a pair of these ports.
As a quick test, I connected the Fireface UFX to these USB ports and measured the average noise-floor.
Average noise-floor was exactly the same as when connected to standard USB2 and USB3 ports.
 
It might make a difference with super cheap devices.
But as was mentioned above, with a quality unit... you'll see no difference.

SuperG
Having formerly worked as an engineer with communication protocols, I get peeved when I sense a lack of accuracy when describing such... Too many hours coding to the wrong specification can do that to you...
 
...
 
Bits are bits.

True. As long as all of the bits get from one end to the other.
 
After two years working as an asst. crew chief on the Neutrino beam line at Fermilab National Accelerator Laboratory, I spent the next 20 years doing SCADA (Supervisory Control And Data Acquisition) over radio. I designed solar-powered master and remote telemetry units (MTUs and RTUs), and then went on to run the systems engineering department.
 
One day, while walking down the hall, I observed two design engineers with their hands in their pockets, staring at the prototype of a custom RTU they were developing for Amoco Pipeline Co (after having been given $750K to do the work). They had a signal analyzer hooked up to it, but their eyes were as blank as the analyzer's display. I stepped in and asked them "what's up?". Well, apparently, they had signal on one card, but not the other that was connected to it by a 40-pin ribbon cable. They just couldn't understand why there was no signal on the far side of the cable.
 
I took one look at their schematic, started laughing, walked out and headed to my old boss' office to tell him he had two morons working for him.
 
They were trying to drive the address and memory busses directly from the CPU chip with no buffering drivers.
 
Cables and connectors can act like chokes (inductors). Square wave (ones and zeros) in. Tiny little rounded bumps out.
 
For a bit to be a bit, it's got to get to the far side in such a condition that it can be decoded correctly.
 
If you've got a crappy cable, it's just not going to work...and you'll know it, no problemo.
 
I don't need a USB audio conditioner. I need a DAW audio improver!