How are top designers reducing digital edge? Banished completely?

Phelonious Ponk

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You were referring to noise - galvanic isolation helps by separating the grounds but does not give you complete immunity to noise. The frequencies involved in digital audio serial transmission are much higher than the audio frequencies - leakage of noise is much more difficult to control.

Is there an answer in there to "what kind of isolation did you have in mind?"

Tim
 

microstrip

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Is there an answer in there to "what kind of isolation did you have in mind?"

Tim

Well, you made a statement and I asked a question. You answered my question with a question. I tried to answer stating that something that can leak RF noise can not be considered "isolated". Sorry I do not see anything else to add, except that many people consider that "galvanically insulated" is a miraculous property, but it is not.

You seemed very sure that your DAC is isolated from the hard disk considering electrical noise - I would like to know how it is done in your system.
 

Phelonious Ponk

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Well, you made a statement and I asked a question. You answered my question with a question. I tried to answer stating that something that can leak RF noise can not be considered "isolated". Sorry I do not see anything else to add, except that many people consider that "galvanically insulated" is a miraculous property, but it is not.

You seemed very sure that your DAC is isolated from the hard disk considering electrical noise - I would like to know how it is done in your system.

Well...no. I said I know my hard drive can create noise and that's why it is isolated. I didn't say, or even imply, that the isolation was perfect and all-encompasing, but I'm very curious. Galvanic isolation, as I understand it, prevents current flow entirely; no conduction path exists. Any information must be passed through something other than electrical current. How would electrical noise from a computer pass through? How would it otherwise need to be isolated?

Tim
 

microstrip

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Well...no. I said I know my hard drive can create noise and that's why it is isolated. I didn't say, or even imply, that the isolation was perfect and all-encompasing, but I'm very curious. Galvanic isolation, as I understand it, prevents current flow entirely; no conduction path exists. Any information must be passed through something other than electrical current. How would electrical noise from a computer pass through? How would it otherwise need to be isolated?

Tim

Tim,

The term galvanic current means direct current - it comes from the name of Luigi Galvani, the Italian scientist who found animal electricity. It was Volta who referred to the DC current created by chemical reactions as Galvanism and it stays so. Galvanic insulation means that no DC current can flow, but noise is AC an can flow through a device that is galvanic insulated - mainly through capacitive coupling. Also the noise can be mixed with the digital signals themselves and than goes through the inductive path, as usually galvanic isolation is just a nice name for pulse transformer coupled. Digital coupling can also be done optically, but I do not know of any USB use this mode of coupling in DACs - perhaps our members know of it.
 

Phelonious Ponk

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Tim,

The term galvanic current means direct current - it comes from the name of Luigi Galvani, the Italian scientist who found animal electricity. It was Volta who referred to the DC current created by chemical reactions as Galvanism and it stays so. Galvanic insulation means that no DC current can flow, but noise is AC an can flow through a device that is galvanic insulated - mainly through capacitive coupling. Also the noise can be mixed with the digital signals themselves and than goes through the inductive path, as usually galvanic isolation is just a nice name for pulse transformer coupled. Digital coupling can also be done optically, but I do not know of any USB use this mode of coupling in DACs - perhaps our members know of it.

Thanks for the history lesson.

Galvanic isolation is a principle of isolating functional sections of electrical systems to prevent current flow; no direct conduction path is permitted. Energy or information can still be exchanged between the sections by other means, such as capacitance, induction or electromagnetic waves, or by optical, acoustic or mechanical means.

The isolation I'm talking about is in my USB converter, not my DAC. I'm pretty sure it's optical, but if it's not, the 2 feet of optical cable between the converter and the DAC ought to do the trick. To be honest, as far as I can tell, it didn't vanquish any noise, not even when I was running it on it's optional battery power. The little bit of noise I could once hear, deep in the background with my ear next to the tweeter and no music playing, went away when I plugged the computer into a separate circuit from the audio signal chain.

Trust me. My audio gear is isolated from my computer. Now you can tell me all about the evils of optical and jitter, and we can start anew.

Tim
 

JackD201

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I had a bad experience a few months ago when I was asked to edit a finale program for a friend on Logic. My home desktop (G4 Quad) is set up so the tower is on the same surface as my active monitors. Not exactly what I would do if I meant to use the desktop in this way all the time. The acoustic feedback from the monitors would cause massive read failures and alarms. I'm talking failure to play not "distortions". Proof positive that hard drives require some form of mechanical isolation for best performance in this instance. Oddly enough this problem never came up when just playing music perhaps because when just playing music it's playing off of RAM.
 

JackD201

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I think a lot of the edginess comes from the analog output stages. Just like so many early transistors stages were edgy, so were many early (and many present) digital playback devices edgy. What I noticed about most great sounding SS digital devices is that the output voltages are higher than the usual 1 or 2v. I think recent stages are handling the chip outputs in a more successful way, not getting overloaded on transients. Heck that's just my theory. No idea if it holds water.
 
I use a list in priority order to attack this:

1) reduce jitter
2) eliminate or minimize effects of digital filtering
3) improve the volume control technology - eliminate the active preamp
4) use fast-reacting low-noise voltage regulators for digital and analog circuits
5) eliminate ground-loops by isolation, both digital and analog
6) use discrete output stage
7) run balanced
8) provide enough energy storage for low-frequency transients

Do all of these well and it will sound like analog. In fact, the dynamics and detail will outperform vinyl.

Steve N.
 

mep

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Originally Posted by tomelex
record an LP to a disc, play it back, and then tell me where that "edge" is! I have done this with my digital recorder, and no, it does not produce an edge. Edges nowadays are due to the mix/mastering and playing IMO, all aspects of digital to its extremes, and plain old stereo dont sound good pushed to its extremes, it wants some mono, some fr aberrations, some hf splash, etc. Thats just me, my experience, my gear, my ears. Perfect sound forever meant that once recorded, it would be the same forever no matter how many times it was played, compared to the never the same song twice LP system or the same with the never the same sound twice tape. CD is a storage system, and yes, it will not last forever, but to confuse what we perfer to in sound vs the storage medium is becoming a bit worn, but thats just an old carmagruden like me who has perhaps blabbed a few thousand times too many about my hobby. aha ahah.

You can't push digital recording past 0VU because the glass will shatter. But, your other gross generalizations about what stereo "wants" are just nonsense and saying if pushed to the extremes it doesn't sound good is just wrong unless you are talking about digital recording. And all of this talk about LPs having the bass summed and making it out to be something terrible is nonsense as well. Low bass is omnidirectional and it really doesn't matter in the grand scheme of things if the low bass is summed when its cut on LP. When you play jazz LPs that came from live recordings, you can always tell exactly where the stand-up bass is on the soundstage. If all you were hearing was true mono, the bass would always be coming out of the phantom center which you also hate.
 

Al M.

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Low bass is omnidirectional and it really doesn't matter in the grand scheme of things if the low bass is summed when its cut on LP. When you play jazz LPs that came from live recordings, you can always tell exactly where the stand-up bass is on the soundstage.

That is what I would expect. My subwoofer is on the left side, but contra-bass (jazz, orchestral) usually comes from the right side where it is located in the recording (with jazz this varies a bit more). The upper frequencies of the instrument (transmitted through my main speakers) guide the directionality of its sound, including the perceived direction of where its low bass content comes from (the same direction of course).

Why did I put my subwoofer on the left side? Because it doesn't matter where it is located. As you say, low bass is omnidirectional and the aural evidence just stated confirms this.
 

mep

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That is what I would expect. My subwoofer is on the left side, but contra-bass (jazz, orchestral) usually comes from the right side where it is located in the recording (with jazz this varies a bit more). The upper frequencies of the instrument (transmitted through my main speakers) guide the directionality of its sound, including the perceived direction of where its low bass content comes from (the same direction of course).

Why did I put my subwoofer on the left side? Because it doesn't matter where it is located. As you say, low bass is omnidirectional and the aural evidence just stated confirms this.

Al-I agree with everything you said.
 

mep

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while your opinons of what you say i say and mean are intersting, i stand by my words, in bold.

And I stand by my comments that I think you are wrong. Stereo doesn't need to have the low bass summed, cutting a master tape to vinyl does. Good stereo recordings don't need or want "fr aberrations" to sound good. Ditto for "hf splash." I know I don't want my high frequencies to "splash" on my recordings. I want to hear high frequencies as close to what I hear live as we can attain in our systems given the current state of the art and the level of performance of our individual systems. If stereo recordings sounded anything like you describe them I would have abandoned this hobby a very long time ago.
 

mep

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I never said that stereo Requires monoing, i was contrasting LP and digital, ie what this thread has tangented off to for a few posts. I appreciate you pursue ruler flat FR, zero distortion, phase shift, zero timing errors, and zero room interferance, etc, others apparently do not, and can admit that when they listen to their SETs or their LPs. And, it still sounds good, infact it is often preferred. Thats me, though, not you.

You didn't say stereo requires "monoing," but you did say "it wants some mono" which makes me think you are trying to split hairs now with semantics. And the funny thing is, I didn't say that you said stereo requires "monoing." So this is sort of a reverse dance going on here. You said what you said and I quoted what you said exactly in my first post. I never intentionally purchased any piece of high-end gear because it had less than ruler flat FR. I also never purchased a piece of gear because it had high distortion. Conversely, I never bought a piece of gear because it had tons of zeros to the right of the decimal point in all of the distortion measurements. Phase shift and timing errors are never stated for audio electronics. Your lucky if you are told whether or not a piece of gear inverts phase.

I am one of those people who enjoy stereo playback. I don't pine for more channels. The better my system gets, the better all my recordings sound. I told you before at the beginning of this thread that the components that have the highest distortion by a large margin of anything in our systems is the speakers. And ironically, you don't see distortion measurements given by the OEMs or people like JA from SP when he measures speakers. It's like the crazy aunt in the attic that no one wants to talk about. If you want to pick on distortions, pick on speakers. But then, you are the guy who uses a high-distortion SE amp when you grow bored with your Hafler amps. You are also the guy that hooks up a DBX box in order to literally breath some life into your system. You sir are in love with your distortions. However, it doesn't mean everyone else wants to be painted with your brush.
 

mep

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For the life of me I can't figure out how a DBX box can increase what wasn't there in the first place. Seems to me for the scheme to work the music would have to be encoded with DBX and then decoded with DBX. And your right, I never owned a DBX box because I never wanted to. I heard them several times and I thought they were horrid little distortion generators. According to you, I never heard one set up correctly and that might be true. I likened the DBX box to an asthmatic weight lifter pumping and breathing.
 

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