Inline analog device brings back audio detail for any recording

Android Central @ CES

Standard electronics lose audio detail during the calculation to turn electricity into music. These canceled sounds are still there, but we don't get to hear them. This little analog device from ReveelSound can fix that.

This small gadget simply plugs inline with your headphones, and those "lost" sounds are restored. It sounds like Voodoo, but the priceless look on Derek's face around the eight minute mark tells me that it works.

Take a few minutes and see John P and Derek talk with Larry from ReveelSound about this revolutionary new product.


Reader comments

ReveelSound makes your music sound alive with any headphones #CESlive


This is a glorified equaliser and bordering on being a scam product - why is it being highlighted on AndroidCentral???

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Agreed about the Audioquest Dragonfly. Amazing performance for the $ and it does make a difference. Not sure about this device. Need more technical info.

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I don't know how this works and have no personal experience to say whether it's better or worse than anything else out there past present or future, but I'm calling it terrible anyway.

If it has a quality DAC like the Dragon fly and the price is right it might be worth it. Wolfson, ESS sabre, burrbrown, etc.

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A DAC's not going to do much inline with headphones, it's already analog at that point

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If i understand this correctly - the "hidden" or "lost" parts are still present - just shifted out of phase.

And this thingy recovers them and adds them back to the main signal.

That sounds plausible.

It isn't plausible.
The device in an basically an inline amp+filter and has no way of knowing what processing has been done to the original signal to even begin to try and reverse it

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This is from a similar product:

"The input signal (which comes from one of your sources) is used as the phase reference. This signal is split into multiple copies of itself, with each copy independently phase-shifted by varying amounts (the “phase layering”). The multiple signal components of varying phase shift are then combined into a single signal along with the unaltered reference. This single signal thus contains the original unaltered signal and multiple copies of itself that have been subjected to varying amounts of phase shift."

"Essentially the idea was to get out of a single signal both the in-phase information and the out-of-phase information, the way I was getting it out of an omnidirectional loudspeaker.
Now, how do you do that in a signal? I just began experimenting. Of course, if you have complete phase reversal of a signal that’s equal in amplitude and frequency you have complete cancellation. I wondered if that energy really disappeared, or if was being smothered out. In fact, my partner in this, who also helps me with my patents, Rob Clark, is an expert in this field [Dr. Robert L. Clark is Professor and Dean of Engineering and Applied Sciences at the University of Rochester—Ed.]. He’s written a book on active and adaptive noise controls, which deals with active noise filters.
But I began to try to figure out a way of tricking the signal so that part of it would play and another part might be cancelled. I then tried layering different frequency paths. Let’s say I took a limited frequency band up to, say, 3kHz. I’d let that play. Then I would take another band-limited signal from 3kHz to 6kHz and put it in the opposite phase. Now they’re playing together. They’re not interfering because the two are not really playing the same frequency simultaneously, If you keep doing that with other frequency bands, it’s like weaving frequencies. A group of frequencies will be in-phase to a limited bandwidth; another group of a different bandwidth will be out-of-phase; and I would add these layers until the entire audio bandwidth from 20Hz to 20kHz was covered. That technique produces a whole audio signal."

Much more here:

..which all amounts to a filter that meddles with phase, no original signal recovery is happening. The resulting signal is just a further distortion of the original, bit like a guitar effects pedal. It MAY be more pleasurable to listen to for some people and some signals, who knows, but there is certainly no signal recovery going on here.

And you are certain that all microphones don´t shift some tiny parts of the original signal in phase HOW?

Just saying "it just is so" without pointing to research done doesn´t sound very convincing...

I'm certain that they do, every component in the recording chain will have its own frequency response with changes in magnitude and phase, my point is that this device has no way of knowing what they are and therefore cannot recover any phase changes.

This device certainly can apply its own distortions, and the results may well be positive for some signals and listeners but the original signal is not being recovered by this device.

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Why not? If done this way

"This signal is split into multiple copies of itself, with each copy independently phase-shifted by varying amounts (the “phase layering”). The multiple signal components of varying phase shift are then combined into a single signal along with the unaltered reference. This single signal thus contains the original unaltered signal and multiple copies of itself that have been subjected to varying amounts of phase shift"

it does not matter what or where it got shifted because you recover EVERY phase shifted information and add it back to the original.

I now think you're trolling me, well played

It can't work as there is no way of calculating the required frequency dependent phase change without either the original signal or knowledge of the recording chain.

If you think that adding multiple copies of the same signal with a variety of phase changes can help get to the original signal then good luck to you.

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I am serious.

Of course the process is much more complex then described. And yes - it sounds like voodoo. But: If the "lost" information is still there (and you agreed on that) - then there should theoretically be a way to recover it.

Did they found the way? I don´t know. But just assuming NO because we don´t belief in it is not very scientific...

When i watched the video i assumed we would say something like "and with our patented DSP technology we found a way to digitally reconstruct and restore the missing data." Because that sounds hi-tech and exiting.

And what did he said instead: "Its all analog". Bam. That really caught me by surprise. I thought: "Wow. That sounds really lame. So either he is a complete marketing idiot - or maybe this thing is for real..."

Lost information cannot be recovered, phase can be manipulated which effectively rearranges the existing information in the signal. Again, there is no way of manipulating it closer to the original without knowledge of the original or the recording chain.

It's the equivalent of a guitar effects pedal with a particular filter built in. The talk on the video of widening the sound almost certainly means it's some kind of subtle echo and reverb effect. A distortion of the signal passed in.

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It's all analog because it's a simple amp + filter network designed to extract money from audio enthusiasts without enough knowledge to see the scam.

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I'm with you 100%.
You might be able to reverse some of the damage done to a signal if you have good knowledge of the previous processing *and* nothing has been lost.
Mostly, especially with analogue, all you can do is make the signal worse. About the best you can do is equalise frequency ranges to compensate for cheap speakers or phones.
This seems to be the same movie trick used in CSI which can turn a low-grade mobile phone image into a super high quality DSLR one.

Damn, Derrek... If you don't want to be there, I'll go for you! Smile or something.

"I'm John *points one finger in the air enthusiacally* V!"

"I'm... Derrek... Kessler... Beep... Bop... Boop... Beep.... I am a robot and you do what I say... Whoop, whoop! Raise... The... Roof... Mo-... Fos.... It's CES! "

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I've been produced in music for awhile now, if the microphone picks all this sound up, it's lost when it goes through the computer and out to the producer who's listening to it. He then tweaks it to sound good not hearing these lost sounds again. If you somehow know the exact sounds lost and reintroduce then I can't see it sounding better, maybe sometimes, but the original production is already made to sound as good as possible (or atleast attempted to). Don't see the use...

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