USB audio cracked... finally!

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Hi Mani,

 

In my view, "cracking" USB means that whatever hardware is before the input becomes (nearly) irrelevant (as long as the processing power can cope with the upsampling requirements).

Can this be achieved with the Phasure USB input + cable?

 

Cheers,

Ricardo

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7 hours ago, rando said:

Could you clarify the meaning of this photo comparison.  In general, outside of the supermarket women's magazines, leaving the pores attached to female faces is considered a hallmark of good quality post-production.  In your example a filter was simply applied over a lengthy professional conversion that  had already created an unrealistic ideal.  Which would seem to be at odds with your impression of this cable.  

 

 

 

I agree.

The image on the left has rolled off highs, warmer tones and looks a little blurred.

 

I wouldn't call it solving but masking.

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1 minute ago, BigAlMc said:

Hi Mani, 

 

I'm not technical enough to know if this is a stupid question but if there is a USB output port (server, NAA, computer etc), a cable (the Lush) and a USB input port (DAC, ISO Regen etc) then does the cable get to drive that its PeterSt's non USB 2.0 protocol being distributed? In other words would my Microrendu and ISO Regen in my case not still be supporting USB 2.0? 

 

Regards, 

Alan 

 

I'd ask that question to Peter but my guess is that we are facing an improved USB 2 spec and not a departure from it.

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43 minutes ago, mmerrill99 said:

One thing that's clear - it the phisolator is only using the Silanna isolator with no urn reclocking after it, then it is introducing jitter into the USB signal - that is a fact.

It may explain why some cables sound clinical & involving?

 

What does "clinical" or "involving" mean?

 

In my experience, as you remove playback-generated "grime" from the signal the sound becomes "smoother"/"softer" and you can hear more of the recorded detail.

But I don't know how this can be applied to a USB interface/connection.

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20 minutes ago, PeterSt said:

 

 I know. And I was going to get back at this anyway. Here :

 

 

Things are not as they seem. By far not.

With the notice that all isolation introduces jitter :

 

....  How much jitter was actually there in the first place ? Now notice that we did not see any plots / eye diagrams of that and what's known from Uptone does not show the comparison (there is no complaint anywhere, and just my observation). However, it can be measured. Ehm, for my own set up. So ?

 

The jitter of an isolation device is a quite complex matter, as it is not shown nor proven by any means (that I even have seen) how jitter emerges in that one particular situation. So think about this ... jitter ... why ?

All is about delay in the first place. But delay is no jitter.

When more than one path is involved like USB has two of them for the data alone) then we talk about (possible)  skew. But skew is no jitter again. However :

 

Once there is skew in order, this is very highly challenging for jitter. Why ? well, because the one bit of current needed for the one signal, is detrimental to the current needed to the other signal. And NOW all bets are off.

 

Lastly, but this is very personal, the jitter specs of that chip must have been observed by someone who by now must have OCD because of jitter, because he thinks that the jitter itself causes the chip to fail. Alex said "Ask PeterSt" and I say "ask Alex". Or IOW, those (chips) guys don't know what they are doing anyway in this particular situation, so all is up to ourselves to make it work. And so we did. And this includes attacking jitter or the effects of it or otherwise it just does not work (for hdds it does all right, but not for isochronous audio data).

 

OK, a far too long post about all what is not related at all. But a bit of background.

The post could be an introduction of something which *is* important : I see the Lush compared with jitter bugs and regenarators and that kind of things - no. It is just a cable. No active devices in there. Also no resistors. A cable. But nothing like a USB cable. But USB is transferred over it. 

 

 

So what have you achieved by not complying with the USB spec: a more accurate audio signal transfer or "better" sound?

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5 minutes ago, PeterSt said:

But this is one of the great aspects of the Lush. It seems it is able to smear (just saying) but pertain the detail. This needs more elaboration (but is not easy).

 

A bit like a (good) CRT vs. a flat display?

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1 hour ago, PeterSt said:

 

FWIW, I don't think so. It is the protocol doing the damage (that's a bit tough but alas) and that won't change a thing.

Btw there won't be much difference with using a PCIe interface with USB outputs. And on that part, we (over at Phasure) tried many things regarding this, up to everybody using a Silverstone USB3 card, just because it sounded special. But other elements caught up with it and I don't think many use it any more.

The thing here is, once you can hear a bit more fro your system, everything matters regarding USB. Buy 10 different PCIe cards and they will all sound different and you will keep one as your best one. Until the Operating System changes - then you have to start all over.

Buy a JCat Femto etc. card - that too sounds different.

 

In the end those "tweaks" don't work, because they work by random aids. Your system suffers from something, and the aid will change the sound. Will it be for the better ? actually you will know when you e.g. buy another DAC and suddenly it does not work for the better any more.

From the point of view of the manufacturer it can be looked at differently with the same conclusions : if something works for really everyone, then the application is really good in absolute sense. And the fun is that when working in a quite close group, this is easy to detect (but also carries great responsibility). What I mean is, once an application has been worked out and it works for a 100, then when a first comes along where it does not work, then

a. I need dare to say that something has to be wrong at the customer's end;

b. The customers needs to have an open mind and help searching for the culprit.

 

A bit of a blabla story but this is really how it can work and how everyone can help each other and make progress.

Back to the quote above, what can be predicted is that the speed of e.g. USB3.2 helps to overcome problems in general (the speed is by far not needed for audio but spades of headroom is always a good thing). This is (in my view) how USB3 always sounded better than USB2 (at the PC's end) and how a USB3 hub in the ISO REGEN sounds better than a USB2 hub in the same environment. We shouldn't make this a subject in this topic, but a lot with audio (if not all) is about headroom we don't anticipate because we can so-called calculate it isn't necessary.

 

Hi Peter,

 

Have you ever thought about designing a dedicated PCIe USB card?

Wouldn't it be better to have full control over the interface?

 

R 

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1 hour ago, jabbr said:

 

Those little transformers have parasitic capacitance > 0. a.k.a. "leakage current"

 

Leakage can easily be solve with a box of cat litter sand.

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Is this the time when you finally discuss cartridge loading and SI? 

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2 hours ago, PeterSt said:

 

Well, the emperical approach seems to be the only feasible approach. And in the end this *is* what we are doing. But it takes ages (I am talking in terms of years, really - and those are only the years behind us).

 

I must note that such a path is the most dangerous because it depends on my ears (and the ears of only a handful of others in the same "field"). So what happens is, that I judge something as sounding better (which already takes me a week to be sure) to next reason out what actually happened at the technical level. And well, as we can nicely see by this topic, is how a world of "power" is not really capable to draw firm conclusions. What also has been shown is how member marce, who for sure is right in the EE field and possibly better than all of os (for sure more experienced than myself), also would not be able to get there on his own, because he already does not recognize the problem (or maybe by now he does). So it takes rarities as John Swenson and possibly me, to be motivated to work out "something" while we don't know what the something is. We do recognize a problem "somewhere" though.

 

Why hasn't anyone come up with a more effective alternative for connecting a Computer to a DAC?

 

Do you think this kind of problem is inevitable and as such may as well be tackled in the USB connection? 

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8 minutes ago, Paul R said:

Adding in subwoofers and super tweeters and multiple channels and complex digital audio processing, etc... to me, that is all audio in the "complex" phase. Soon enough it will settle out to the point where even "lifestyle" equipment sounds as good as or better than the high end gear of yesterday.

 

I don't think that DSP can improve bad drivers or increase the dynamic range of small cones in small boxes or correct the dispersion pattern of a carelessly designed speaker.

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Counter-EMF? 

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8 minutes ago, PeterSt said:

 

No points for you Mani, and what I bolded is too intelligent (you added that later) and does not help you. Haha.

 

 

Ricardo, I think you changed something too, or I have "Back EMF" too much in my mind as the phenomenon.

Anyway, 10 out of 10, and 11 out of 10 if you removed the "back" from it.

 

So yes. But now why ?

I am going to grab some coffee.

 

Apparently it's more than just your average "handshake"...

 

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17 minutes ago, PeterSt said:

 

Ah Mani, you can do better. Anyway, worth 2 points I'd say.

I am considering deducting a few from Ricardo because maybe he was guessing too much. 

 

That's not fair. 

 

My comment wasn't even referring to loudspeakers (not with cEMF nor with the arm wrestling photo), but was instead a speculation regarding USB and audio signals.

But ultimately you are right, I am just guessing (for lack of knowledge in electronics).

 

P.S.: you are looking for "control" and the EMF "analogy" made sense...

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I suspect that you are applying dynamic compression to the signal, @PeterSt

 

That's not a nice thing to do. 

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5 hours ago, Doak said:

Suggestion: 

If you are actually interested in the item/topic under discussion here, please set about acquiring a LUSH USB cable, insert it into your music playback system for a while and then decide what you think about it.  

In the end, for YOU and your system, there is only one opinion that matters: YOURS.

 

Corollary: In MY system, MINE is the only one that matters. 

 

 

I don't use a USB connection but am still interested in the topic.

What should I do?

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2 minutes ago, PeterSt said:

 

Get yourself the cheapest DAC with USB interface available and proceed from there ?

 

(not sure how serious you are with your question )

 

 

I have been waiting for my bespoke PCM NOS DAC for ages but it seems that the builder has other things in hand...

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1 hour ago, PeterSt said:

 

Ehm ... Which one would that be ? (somehow I am getting anxious)

 

Don't worry, it's not yours.

It's not a commercially available DAC.

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2 minutes ago, PeterSt said:

@semente

 

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On 02/08/2017 at 9:11 PM, Guidof said:

By now I've listened with the Lush in the system to a wide variety of music (mainly jazz and classical) for several days. It replaced a Curious USB cable between my ISO REGEN and Benchmark DAC2-D. Here is what I hear:

• More silent silences ('blacker blacks')
• Greater dynamic range
• More accurate timbres
• More natural voices
• More three-dimensional sound stage
• More engaging reproduction of rhythmic passages
• Greater density of musical information

Taken together, these qualities result in effortless refinement and stunningly lifelike sound. This is indeed a breakthrough product. The price is steep (close to 300 USD when exchange rate, Paypal fees, and UPS shipping are factored in), but not outlandish when the sonic gain is considered.

 

My overall impression (uneducated guess?) is not that the Lush imparts any particular sound signature to the overall musical presentation, but rather that it somehow allows the sound of the rest of the system (upstream and downstream of the Lush) to come through unimpeded.

 

There IS a downside: While the sonic virtues of a good recording are thus revealed, so are the pitfalls of a poor one. This has been true for me with any improvement in the USB chain.

 

 

A few of the improvements that you are describing can be attributed to lower noise floor.

This brings up a few questions:

 

Why is this lower noise floor audible if it's the result of changes to the chain before D/A conversion?

Is the noise affecting the performance of the D/A chip?

Is the noise reaching the analogue stage through other means other the aforementioned chip?

If it is audible then it can be measured, right?

 

Or is it something other than noise, like transient response?

Isn't transient response also measurable?

 

Or am I completely off target?

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6 minutes ago, fas42 said:

 

How many times have I been asked this ... ?

 

Usually it doesn't end well - I don't supply simple, straightforward answers that anyone can apply - and the other parties get frustrated, .

 

Since this place seems to have a high percentage of IT folks, and that's my background too, I will say that it is a process of debugging. Because, that's exactly how I see it - a computing system can be of enormous usefulness - or, a total disaster - what's the difference between the two? Quite often, the number of bugs - zero bugs equals happiness; lots of bugs, extreme frustration. And I see most audio system as having a substantial number of "bugs" - the only real solution is to track down each one, and fix it, in some manner - one after the other.

 

So, the fine tuning is a process of discovering each bug, and dealing with it. The bugs are infinite in variety, just like those in software - so there's little point in trying to describe them. Usually the biggest difficulty is understanding how to be become aware of them, that's a large part of the exercise. I normally do this by turning up the volume on 'difficult' recordings, and listening carefully - experience then helps in identifying the possible areas where a particular "bug" - an audible anomaly - has been triggered.

 

Anyway, this thread is about the Lush cable - further discussion should go in the blog area, or another thread.

 

If the "bug is the nasty resonance of a kevlar midrange cone how do you fine-tune it?

Do you fiddle with the crossover, try some EQ-ing replace the driver or the speaker altogether?

 

What if the amplifier has a high output impedance and the combined frequency response goes wild when you partner it with a pair of speakers?

 

Or the power supply is limiting the amplifier's dynamic abilities?

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19 minutes ago, PeterSt said:

 

I think that is another testimonial of the same thinking. But a little different because this is key to everything :

 

Whatever you have, start expanding it for the better instead of buying new (or trial new). For me it shows everywhere, up to exactly never coming up with a new DAC and always expanding the base one. Some have send in their NOS1 for the 6th time. And it can always get better; it just needs time to think of something.  But point is :

Only if you keep your gear, you learn how it behaves and super crucial : you thus learn how other new goodies behave. Or, what could be the matter when it suddenly does not sound any more (the real bug seeking).

 

Of course you must be lucky enough to "buy" this base which is inherently (sufficiently) good ...

 

I agree with all of this.

 

First you must start with a good base, which requires an effective listening assessment methodology, knowledge of what is possible to achieve and as skill, the ability to interpret measurements and a realistic budget. (I avoid reviews, particularly those coming from the press).

Next you must identify it's shortcomings, then a) you have the technical expertise and equipment and can perform your own modifications or b) try to shortlist a couple of replacements that must should address those shortcomings whilst own shortcomings of replacements must not be more significant/damaging.

 

And to address problems with the filter slopes, loudspeaker drivers, power supplies, etc. it also helps if the equipment is of a modular construction (i.e. horns, electronics with external PSU, etc.).

 

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27 minutes ago, PeterSt said:

 

Well, I am a bit acquainted with horns. With horns your biggest bug is resonance. So what do you do ? change the filter (not the crossover). But mind you, this could not be very normal "behavior" because any normal speaker won't have a notching (and certainly not boosting) filter. Maybe only for the roll off at the end of its range (the crossover at the other end). 

 

Replacing the driver could be easier, but THEN you'd be in need of changing the crossover. And it gets worse and worse.

 

Horns make it easy to change things (filter slopes, compression drivers horn profiles) because they're of a modular construction.

 

You still need to know what you are doing, use measuring equipment and things will get expensive very quickly...in my experience.

Then you add dedicated amplification to the equation and the budget just takes off.

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1 hour ago, fas42 said:

 

All of those things are valid "bugs" ...

 

I have been mighty impressed by speakers so far - they nearly all come to the party if everything else is in good shape. A nasty resonance which was so obvious that it was disturbing I haven't come across yet - but if it required the sort of measures you mentioned then all are possible approaches.

 

With FR, I find that when other matters are resolved then a "wild curve" subjectively is not a major problem - I haven't used 'weird' amplifiers over the years, it's always been conventional SS.

 

With powers supplies I'm on solid ground - I have done lots and lots of work in this area over the years, to improve the performance of amplifiers - it's absolutely critical to get right.

 

Well I guess it all depends on one's taste and expectations.

I am quite sensitive to "hard" cone and dome resonances* and also to frequency response / tonal balance anomalies.

 

Edit: * - with improperly implemented filters

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2 hours ago, fas42 said:

 

One listens to music, and especially playback in different ways. What I'm after is the "vibe" that one experiences with live music - with the latter, the FR is all over the place, depending upon exactly how the players are positioned, where you are in relationship to them, the acoustics of the listening space. None of that matters in the slightest with respect to the sense of listening to a live performance - and so I find it goes also with listening to good reproduction.

 

The original base setup that gave me that experience evolved from ordinary quality sound, to something special, by my "debugging" - the key components, the CDP and amplifier, were of a pretty good standard; the speakers, very ordinary. Which tended to guide my movements forward, my way of thinking.

 

 

 

What do you mean by "with live music (...) , the FR is all over the place"?

Live is reality, it can't be "all over the place"; only reproduction can be "all over the place".

And inadequately balanced FR in playback can change the timbre of instruments and vocals.