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iTube, Euphonia and Confused Thinking

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#1
Hi, All. I'm a new member here just crawling out of the primordial ooze of mainstream subjectivist magic thinking. I was wondering if anyone has ever heard or used the iFi iTube or its successor iTube2. Is this unit (a) a useful tool to tweak sound to one's admittedly subjective, but no less real, preferences, (b) an insult to what might otherwise be a reasonably faithful audio reproduction chain, or (c) something in between? Your considered thoughts would be most welcome.

Cheers, Alex
 

tomelex

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#2
Hi Alex.

I think you need to be clear on a few things as you emerge from the swamp.

--If you are listening to speakers in a room, moving your head a few inches in any direction could create linear distortion changes (FR) of a db or more in certain areas of hearing range. Thus, the room and speakers interaction are the biggest change to the sound and this changes as you move your head around, decoded, if you don't lock your head in a vice don't think that you will ever tune your system for repeatability. Goes for headphones but only a little bit, with them its where you position the headphone on your ears or in your ears each time. So, that's a big variable right there. Summary, position of your head using speakers and room or the headphone on or in your ears ALWAYS makes a change.

--Changing anything in your system so it sounds better to you is fine, just remember paragraph above...
 

Blumlein 88

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#4
The iTube says it does a few things. One of them is said to be the Taddeo digital anti-dote. Here is what I gather the Taddeo device did.

Here is a close up view of a single maximum pulse. The upper one has had a brickwall filter applied at 20 khz and you see the ringing each side of it. The lower one has not had filtering.
taddeo 1.png


Now I filter both of them and notice I had already offset the two pulses by one sample. Notice how the up and down 'ringing' would mostly cancel out if I combined these.
taddeo 2.png


So here is what they combine to if you do that. Notice the peak is blunted, but the ringing is mostly gone visually.

taddeo 3.png


Now I didn't show it yet, but in that same file I had a 20 hz to 20 khz sweep. The upper one is with two of them offset by one sample and combined. The lower one is how such a sweep looks with flat response. The treble is rolled off and the Digital Anti-dote said it was down -3 db at 15 khz. This is a little more than that, but similar.

taddeo 4.png


If I do the same procedure with square waves they also when offset by one sample and combined cancel out nearly all the "ringing". You would think offsetting a duplicate of a file and combining might sound messed up. In fact, other than the softer treble and a warmer balance you'll not hear anything wrong. It sounds more "analog". I'm of the opinion there was no ringing problem solved here. Just equalization to a similar curve gives a the same sound. There once was a analog version of the Digital anti-dote and it was working in a similar manner. It delayed and changed phase of one copy of the signal and combined with the original signal to achieve a similar result.

The iTube also does a couple other things. And you can use a tube in the signal path. I am pretty sure none of them 'repair' digital sound. The 3D sound by description might be partly a mid-side shuffler circuit first described by Alan Blumlein in a patent in 1933. It may do this a bit differently. But the widening of the stage, and correcting for recordings with an imbalance of lows sounds like the same idea. And they mention Alan Blumlein.

So I have no doubt it would change the sound. You may or may not like it. It would be a step away from pure fidelity which is still okay if you like the result. But they aren't repairing anything. You also could do a few tracks yourself and see what you think of the sound. If you like I could give instructions on what to do using Audacity as a sound editor.
 
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#5
@Blumlein 88, thank you so much for the thorough (and graphical!) analysis. That sheds a lot of light I think on what's going on with the iTube. I imagine it has a certain utility as an "on the fly" and somewhat crude compensation for a system (or listener?) suffering from over-emphasized trebles. But otherwise, not so much.

Thanks again,
Alex
 

bunkbail

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#8
Do you mean you can't hear it doing anything, or you don't like what it does or it does something and you don't know how?
I can't hear any improvement to my system. I've never owned a tube amp before, so I bought it to experience what a tube amp could sound like but honestly when every time I plugged it into my system (I own several DACs, headamps and headphones), I barely notice any differences at all tube modes (classic, SET, push-pull), except for the 3D mode and bass boost (they have obvious impact).
 

tomelex

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#9
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While I dd not research this device you guys are talking about, to obtain a SET sound you must have a final tube power amplifier, an output transformer and speaker combination.
 
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