SD card transports

Interesting points.

I wonder what effect adjusting the streaming buffer capacity would have in software.
ITunes and other players let you do this. Might try later playing a track then powering down the HD to see how long the buffer runs on the different setting - assuming it still plays which I think it should.

 

Im having trouble seeing how jitter (if that is a source of variability in SQ) is increased if the drive head seeks to a location and reads data into the drive buffer. Why would this affect jitter? Where in the audio chain is jitter measured?

I fear that there is a notion that because a HDD is electromechanical it somes with a bunch of nasties that affects SQ, and a memory stick is free from such nasties. I say that notion is incorrect.

 

Absolutely spot on

 

The explanation I have been given is that the problem has more to do with power supply corruption than with the actual data seeking. I conclude from this that the motor and the servo in the HDD are guilty of “dirtying†the power line. If this interpretation is correct, an SSD should not have the problem and should give the same results as putting music files into a RAM drive for playback. Unfortunately it is not yet possible to buy a large capacity SSD that could store a big music collection. My own collection can fill three 500Mb HDDs.

Let me say that I make no claims of my own in relation to memory playback. I report only what I have read. I am searching for answers for myself to help me get the best results and my mind is open to all information and all opinions. Changing to a RAM drive seemed to bring a good improvement in my own system, but I cannot say with certainty that there were not other mechanisms at work or that my perception was not defective. I am a music lover and not an investigative scientist!

 

But data from the hdd cache also 'goes through' system RAM anyway, so there is no difference. I would like to see 'dirty power' created by a HDD too as by the time data is read from the drive and appears through the line out stage it could be literally seconds difference. I know I sound like a rabid HDD fan, I would because I work for a hdd manufacturer, but believe me it is far more likely to be a fan or the PSU or the graphics card or some other power hungry componant that causes issues. The drive is simply very intermittantly reading pretty large chunks of data which gets fed through various buffers before spilling out to a DAC. I suggest people try AV drives to stream music.

 

Thats exactly why computers are not a good medium for storing music files as there is just to much going on inside. Fan noises, Windows checking, power supplies. Someone said earlier sd cards are crap. Then why are they used for just about every devise there is like, mobiles, tv's, music players, mp3 players, camera's. Because they are versatile and reliable.

 

and cheap and slow and wear out too

 

I believe that there is a forum devoted to the view that anything other than a Macbook with iTunes is unnecessary to achieve audio nirvana! I do not, myself, subscribe to this view and I can see some potential benefits in keeping an open mind and trying different routes for myself. Sometimes these routes lead to nowhere, but sometimes they offer surprises.

In my own particular computer there are no fans (not even in the power supply) and no graphics card to cause disturbance, but I can accept that such things could very easily swamp any issues connected to the HDD.

I have not made A/B/X testing of the various stages through which my audio computer has passed because to do so would be difficult. What is easy to do is to connect my normal everyday PC to my audio system and make a direct comparison with my carefully optimized audio PC. My everyday computer has a good specification, but of course has a graphics card and a full collection of fans and assorted media drives. It operates under Windows XP and, unlike my audio PC, the bios settings are the manufacturers defaults and the operating system functions with all the regular services enabled. It has no RAM drive and takes data from the HDD and cache in the normal way. It does have ASIA4All installed to overcome the KMixer issues in XP.

With my audio computer I normally use cPlay as the playback software and my files are stored in WAV format. This makes direct comparison with my everyday computer difficult and so I converted a representative selection of files to ALAC (allowing me also to compare a MacBook) and installed Foobar on my audio computer (still keeping the RAM drive) so that I could make a comparison. I was very satisfied that all my work has not been wasted.

There is some published information about HDD induced power line noise and it is easy to Google for it. http://www.cicsmemoryplayer.com/index.php?n=CMP.03Jitter is perhaps interesting with some information about jitter.

This is a long post and probably too long. I should not have hijacked this thread and for this I apologize.

 

Thats an interesting link and the last lines sum it up nicely.

"In a Computer Transport, parameters like RAM settings, RAM quality and motherboard traffic all make a perceptible difference. The purity with which data is streamed to the DAC is critical. It is here that cMP excels – measurably. "

 

Not really they are becoming fast now and fast enough for music requirements. Cheap is all ways welcome and i haven't had a single card go on me yet, and i use them daily. As always you look after things and they will reward you with long service.

 

Hi Craig,

How life treating you at the moment?

Still @ Seagate then

 

howdo tony, Im at WD now

 

I read this often, so measure it and lets see these effects.

Lets see the raw supply effects on the rails and then lets try to establish if any effect is present on the output. A nul will do that.

As with so much in audio - what might be happening at a purely theoretical leval is taken as fact - and as audible!

 

There are people much better qualified than I am who have already made these measurements and published their findings. It would be pointless for me to spend several thousand euros on rest equipment to duplicate their work. What matters to me is only whether theories can be put to the test within my own simple capabilities and deliver results which I can detect as helpful to me. I am not a completely stupid man and I can generally tell at first glance if a theory has signs of credibility or if it is clearly foo. I have spent more than 35 years of my life working in stores selling audio equipment and musical instruments and you can probably imagine the amount of theories and counter-theories which have been explained to me. I think that I can now detect the aroma of foo within the first two or three sentences of a conversation. The corruption of computer power lines by HDDs seemed to me to be part of a rare group of theories worth looking into.

In the final analysis, it matters nothing to me if the notion of HDDs affecting the power lines in my computer is no more than a crackpot idea. It was not difficult for me to try for myself the suggested method of avoiding the supposed corruption (the memory player concept). Had there been no beneficial change I could have shrugged my shoulders and continued with my life. But there was a discernable audible benefit and it was in line with what others have described. I don't feel that I must now make measurements which I am neither equipped nor qualified to make just so that I can confirm the information that is already published. Perhaps the benefits that I have gained have nothing whatever to do with power line corruption but are the result of something else completely. I don't care. What matters is that I have the benefits. I can await the findings of capable and qualified researchers to provide an enhanced explanation.

There are a million little optimizations that I have either tried or have on my list waiting to try. The idea of powering-down the HDDs during playback and using a RAM drive was just one item on the list. For every ten things on my list, maybe one yields a result. This one yielded. That's good enough for me.

Take a look at http://www.audioasylum.com/forums/pcaudio/messages/2/27041.html. If you have time to wade through page after page (a lot of it utter drivel) I think you'll find some links or some measurement data relating to HDD supply line corruption. I cannot put my hand onto the relevant pages just at this moment.

 

Also, any access of a data bus can cause interference with the supply lines, regardless of the device on the end of the bus being solid state or mechanical. The ultra high-speed switched electrical signal is what does it.

The ground lines of a computer can be corrupted by such things, but I haven't heard it cross an optical connection, and I wouldn't presume it causes jitter.

 

Within the link I provided you can find the same information and theories that I have read. I make no claims of my own, as I said previously. I simply absorb the information that comes in my direction and try to test the theories when I am able.

There is no magic or mysticism in audio. Every effect has a cause and, given time, the cause can always be explained and measured. I think it is important to keep an open mind during the “grey†period before full understanding comes, rather than adopt a position of dismissal because something does not slot immediately into our current knowledge base.

There are always two possible actions we can take. We can dismiss a theory because what we know tells us that it cannot be correct, or we can put the theory to the test and see if it is the theory or our knowledge which is defective. I know which course of action I like best.

I've exhausted all my thoughts on this subject and so I'll leave it at this point before we enter a dark tunnel from which we may never exit. I will, though, read and absorb any information that others are able to provide.

 

Thank's I'll take a look at that.

What matters in all of these things is what appears at the output of the player/dac.
So the test that matters is the one which firstly establishes by measurement that supply lines are being influenced in some way, however small, and then goes on to look at how this translate to any corruption of the output.
Without such testing you might find you are addressing issues which are of no consequence.

 

I'll just make the point again for clarification that it is not me that is addressing issues. I have simply drawn to your attention some suggestions made by other people. It is not my duty, nor is it within my capability, to prove to you the validity of these suggestions. You can look to the original work for yourself to determine its worth and you can lecture the originators on the folly of their assumptions if you find them wanting.

My own position is nothing more than the belief that I have gained an improvement in sound quality by following a suggestion to power-down my hard drives during playback and take the data from a RAM drive. I do not know what mechanisms are involved, but this does not stop me from recognizing the improved sound quality, just as my not knowing what is inside the dinner my wife prepares for me does not stop me from knowing that it tastes good. I mentioned that supply line corruption has been suggested as a possible cause, but I have no more idea than you if this is correct. Perhaps it is something else which is responsible. Once again, you can investigate the original work for yourself for a possible explanation.

Think of me only as the man who mentioned something that seems interesting.

 

I understand that and was speaking generally - sloppy use of the word 'you' I'll agree.

 

Craig you have PM