AVS Forum banner

Audio Media Server

3K views 78 replies 15 participants last post by  TLCW 
#1 ·
I have a old 2 channel audio system I like very much. based on a Yamaha C4 preamp and a Yamaha M2 power amp which feed a pair of recently overhauled Dahlquist DQ10 speakers.


A few years ago I "ripped" all my vinyl to CDs and then ripped all my CDs to wav & MP3 files. I had to, all the vinyl and CDs were taking over my livingroom.


So my total number of CDs and LPs on CD is about 2000. Stuff that I like and can't easily replace.


My problem is "feeding" the files to the preamp. I built not one but two media servers using micro AT motherboards. The cheap motherboards have terrible signal to noise ratio, then I needed a keyboard and a monitor and a mouse. It is all too much cwarp.


Recently I put all the CD quality mp3 files on a small SSD hard drive. The SSD is in a SATA to USB box. I can plug the SSD drive into any of my laptops or workstations and have all 2000 cds. The ssd drive is the size of one pack of smokes, and I nevr have have to refile LPS or CDs.


Then I put a 3TB hard drive in a SATA to USB box and plugged the USB into the back of flat screen TV and that is instant access to maybe 600 movies?


That got me thinking, (in theory) if I had a $400 netbook with a USB port I could just plug the SSD drive in, then somehow pipe from the netbook to either to the power or pre amp. The magic is not in the media server, what ever I use exists just to pull files off of a tiny SSD drive.


With a netbook I would have a built in screen, keyboard, and mouse. But output signal from the netbook would be not be digital but analogue. So I'd have to have a high quality sound chip in the netbook otherwise I'm just amplifying garbage like I am with my current media center.


Maybe I could find a preamp with USB port? Problem is it might never spec as clean as my existing preamp and then I am missing screen, keyboard, and mouse.


I am open to suggestions gents, and thanks.
 
See less See more
#52 ·

Quote:
Originally Posted by arnyk  /t/1438403/audio-media-server/30#post_22631013


My question to you is what are you interested in, sound quality or numbers?

Amir's post is full of numbers, but unfortunately seems to contain no reliable information about what those numbers mean in terms of sound quality as you use your equipment.

Just to add insult to injury, that post is full of numbers that represent the performance of equipment that has been off the market for years, even the better part of a decade.

I suspect that you are like me - you are a lot more interested in sound quality than isolated numbers, and you're mostly interested in the sound quality of equipment that you are likely to buy now or in the near future.

AVRs are often updated with the latest chips for rapidly evolving functions like processing surround sound transmitted over HDMI. So, the 2006 results could be from up to 7 generations back, and the 2009 results could be from up to 4 generations back.

That all said, the performance test results shown still aren't stated in a way that is relevant to sound quality - its all just isolated numbers.

What you are seeing is much like a proven sales technique called "raising the disturb".
http://www.wendyberry.com.au/the-disturb-factor/w1/i1007077/

"In sales, much time, money and effort has been spent trying to figure out what makes people buy. Simply put, people buy when they’re disturbed enough by their current situation and they realise a need to change it."

What I see is a well-known kind of phoney sales pitch and manipulating people into spending money, not any serious discussion of how to get the best possible sound quality in your situation.

Yep. I'm interested in sound quality. Mid-range gear is what I can afford so I was just curious how it stacks up, pun intended. amirm mentioned "poor implementation" regarding DACs in high volume consumer gear and that's what triggered my response.
 
#53 ·
Maybe Arny will post HDMI measurements of current devices devoid of jitter distortions as shown. For now, the engineers in the field as represented in the new working group at Audio Engineering Society don't agree with him the least:


Technical Report:

2012-1-30 Trends in High Resolution Audio, 2012
Description: Emerging Trends in High Resolution Audio, January-2012

"HDMI, the point-to-point connector required for BR and HD video, has excellent bandwidth and an Ethernet data link (HDMI 1.4), but lacks an audio clock. HDMI receivers must derive audio word clock from the video pixel clock, commonly resulting in very high jitter that affects quality and can be audible. Some high end receivers address the jitter and many companies are researching it but current solutions are expensive and uncommon.


Doesn't paint a picture of the problem having been vanished just like magic, now does it?


BTW, in the next issue of Widescreen Review Magazine coming out later this month/December I address the audibility of these distortions. The limits are way, way lower than what exists here if we want to achieve inaudibility. The analysis involves listening tests by the way although not the in the manner you may be thinking.
 
#54 ·

Quote:
Originally Posted by amirm  /t/1438403/audio-media-server/30#post_22634647


Maybe Arny will post HDMI measurements of current devices devoid of jitter distortions as shown.

Well Amir since you say that have the audio equipment samples and you say that you have the test equipment, and its your issue, it would appear that in a logical world, you would be the best person to do that testing.


By not doing so forthwith, you continue to cast stones at your own claims. ;-)


Nice job of sloughing responsibility when your hobby horse seems to have fallen down and can't get itself back up! ;-)
Quote:
For now, the engineers in the field as represented in the new working group at Audio Engineering Society don't agree with him the least:


Technical Report:

2012-1-30 Trends in High Resolution Audio, 2012
Description: Emerging Trends in High Resolution Audio, January-2012

"HDMI, the point-to-point connector required for BR and HD video, has excellent bandwidth and an Ethernet data link (HDMI 1.4), but lacks an audio clock. HDMI receivers must derive audio word clock from the video pixel clock, commonly resulting in very high jitter that affects quality and can be audible. Some high end receivers address the jitter and many companies are researching it but current solutions are expensive and uncommon.


Doesn't paint a picture of the problem having been vanished just like magic, now does it?

Amir the above post is not a peer-reviewed report so its just the opinions of some people whose qualifications seem to be pretty questionable. For example chairwoman Vicki R. Melchior lists her position as "Audio DSP Consultant" which is about as vague as it comes. She apparently recently retired from Sonic Solutions which gained infamy due to their backing of the now-discredited DSD initiative.


The reports that have come out of that committee have been criticized roundly by the AES Fellows that I hang with. The following includes some of the more technically-challenged work I've seen lately:

http://www.aes.org/technical/hra/


Looks like your kind of people, Amir! ;-)
 
#55 ·

Quote:
Originally Posted by postrokfan  /t/1438403/audio-media-server/30#post_22634571

Quote:
Originally Posted by arnyk  /t/1438403/audio-media-server/30#post_22631013


My question to you is what are you interested in, sound quality or numbers?

Amir's post is full of numbers, but unfortunately seems to contain no reliable information about what those numbers mean in terms of sound quality as you use your equipment.

Just to add insult to injury, that post is full of numbers that represent the performance of equipment that has been off the market for years, even the better part of a decade.

I suspect that you are like me - you are a lot more interested in sound quality than isolated numbers, and you're mostly interested in the sound quality of equipment that you are likely to buy now or in the near future.

AVRs are often updated with the latest chips for rapidly evolving functions like processing surround sound transmitted over HDMI. So, the 2006 results could be from up to 7 generations back, and the 2009 results could be from up to 4 generations back.

That all said, the performance test results shown still aren't stated in a way that is relevant to sound quality - its all just isolated numbers.

What you are seeing is much like a proven sales technique called "raising the disturb".
http://www.wendyberry.com.au/the-disturb-factor/w1/i1007077/

"In sales, much time, money and effort has been spent trying to figure out what makes people buy. Simply put, people buy when they’re disturbed enough by their current situation and they realise a need to change it."

What I see is a well-known kind of phoney sales pitch and manipulating people into spending money, not any serious discussion of how to get the best possible sound quality in your situation.

Yep. I'm interested in sound quality. Mid-range gear is what I can afford so I was just curious how it stacks up, pun intended. amirm mentioned "poor implementation" regarding DACs in high volume consumer gear and that's what triggered my response.

As you see in the post that follows the above post, Amir seems to like to throw stones but generally has nothing factual to back it up even though he claims to have a rich selection of audio gear (AVRs, etc) to test (he says that he's a high end audio dealer), he claims to have the high end (Audio Precision's current model) audio test equipment to do the tests, and from his posting record on AVS he obviously has the time to do the testing.


Amir also claims expertise in doing formal audio subjective testing when he was a VP at Microsoft, but we haven't seen any actual evidence of that either.


In contrast I've got exactly one low end AVR with HDMI I/O on hand which is a last years model that I bought on close out. I'd have to tear my only AV system apart to test it. I do have test gear but Amir has already repeatedly and aggressively pooh-poohed it on AVS. The problem with me doing the listening tests is that my views on the subject suggest that any negative results that I obtain would be a result of my biases.


Why should I bother to try to swim against all that when I'm already comfortable with how this stuff is working out for me?
 
#56 ·

Quote:
Originally Posted by postrokfan  /t/1438403/audio-media-server/30#post_22634571


Yep. I'm interested in sound quality. Mid-range gear is what I can afford so I was just curious how it stacks up, pun intended. amirm mentioned "poor implementation" regarding DACs in high volume consumer gear and that's what triggered my response.

I also like to think of these things in terms of opportunity costs. If you are deciding between purchasing an AVR or a cheaper AVR + separate DAC, another consideration is the room correction software. If the more expensive AVR has better room correction software, you'll typically get a worthwhile improvement in SQ. Unlike DAC performance, that's not controversial. For example, most people find that upgrading to a higher level of Audyssey MultiEQ definitely does offer SQ benefits in most rooms.
 
#57 ·

Quote:
Originally Posted by cel4145  /t/1438403/audio-media-server/30#post_22636159


Unlike DAC performance, that's not controversial. For example, most people find that upgrading to a higher level of Audyssey MultiEQ definitely does offer SQ benefits in most rooms.
I didn't think it was controversial either until I post the results of double blind listening tests showing Audyssey MultiEQ degrading room performance vs doing nothing. On a dime, all the proponents of blind tests became subjectivists defending their personal, sighted, non-controlled observations. You can read the dozen or so pages on this starting here: http://www.avsforum.com/t/1425262/are-audio-companies-all-involved-in-a-huge-conspiracy/840#post_22505809 . Here is part of that post:
Quote:
Originally Posted by amirm  /t/1425262/are-audio-companies-all-involved-in-a-huge-conspiracy/840#post_22505809


Only if the system is not performant and screws up just as often as it does something good. The right system doesn't have such flaws or reliance on luck. Or nearly so. It can be used with confidence that except in rare cases, it will perform and perform well. Great example is the data in front of us in the form of Harman listening tests of auto-EQ products:


The graph on the left shows the mean and 95% confidence interval for each system (higher is better). We see that not only did Audyssey (RC6) underperformed the anchor (NOEQ), i.e. no EQ, but it did so across the board. On the right you can see the actual composite scores from each listener and again 95% confidence interval. Once more Audyssey brings in the rear on the right lowest bars from all. We see that even if you stretch its performance it still gets beat by competitors and no EQ. It was not the case of two guys liking it and the rest not. None liked it.

It seems we are fans of blind listening tests until such point that they dispute our audio beliefs and then we turn against them! Same goes for speakers. Folks talk about blind listening tests but are perfectly OK picking them sighted just because they sound different from each other. Yet listening tests show that we like different speakers sighted vs not. And just as in EQ tests above, people will argue tooth and nail that such blind listening tests are not valued and instead we should trust listening to them in a store.


For Audyssey MultiEQ to "definitely" make things better there needs to be at least one controlled test showing it so. Yet none has been published ever. Even its proponent after reading the above AES report did anything of this sort.


No controversy? I think not
. It is only so if we have not dug in deep and be a firm believer in proper controlled evaluations across the board. As opposed to only in areas we don't believe in....
 
#58 ·

Quote:
Originally Posted by amirm  /t/1438403/audio-media-server/30#post_22637100

Quote:
Originally Posted by cel4145  /t/1438403/audio-media-server/30#post_22636159


Unlike DAC performance, that's not controversial. For example, most people find that upgrading to a higher level of Audyssey MultiEQ definitely does offer SQ benefits in most rooms.
I didn't think it was controversial either until I post the results of double blind listening tests showing Audyssey MultiEQ degrading room performance vs doing nothing.

So Amir, do all audio systems sound alike?


Do all rooms sound alike?


and now for the tricky question, do all Audyssey systems named "Multieq" sound alike?


No, not all audio systems sound the same.


No, not all rooms sound the same.


And not even do all Audyssey systems with the word "Multieq" in them seem to be the same!


How many different flavors of Audyssey systems with the world "Multieq" in them can we come up with?


If I come up with more than one different Audyssey system with the world "Multieq" then the above comment would appear to be misleading since it attempts to conflate them into just one thing.

http://www.audyssey.com/audio-technology/multeq


"FLAVORS OF MULTEQ


Audyssey room correction technology comes in four solutions: MultEQ XT32, MultEQ XT, MultEQ and 2EQ. While they are all built on the same core science, each is designed to operate within the constraints of the available DSP processing power.

MultEQ XT32

Our newest and most accurate room correction solution with more than ten thousand individual control points allowing finer details of the room’s problems to be captured and corrected. The ultra high resolution filters are applied to all channels including the subwoofers, with the most obvious benefit being heard in the low frequency range where correction is needed the most.

MultEQ XT

Our advanced resolution room correction solution with high resolution equalization filters for satellites and subwoofers. Most products with MultEQ XT are installer-ready and can be calibrated by an Audyssey Registered Installer to provide even higher performance for even the most demanding large or odd-shaped rooms.

MultEQ

Our standard resolution room correction solution that uses mid-level resolution filters for satellites and subwoofers.

"


There are others as well, for example an oldie-moldie that was a stand-alone product and not part of an AVR,


Which flavor of Multieq was involved with your DBT?
 
#59 ·

Quote:
It seems we are fans of blind listening tests until such point that they dispute our audio beliefs and then we turn against them!
Um, no. There is a recognized concept in science known as the Single Study Fallacy. You are succumbing to that fallacy in this case. Others are more open-minded.


And it's especially important to be open-minded about a study conducted by a company that has an economic interest in the outcome. That's not to take anything away from Dr. Olive, whom I greatly respect. But this one needs a great big asterisk along side until such time as someone with no interest in the outcome replicates it.
 
#60 ·

Quote:
Originally Posted by amirm  /t/1438403/audio-media-server/30#post_22637100


I didn't think it was controversial either until I post the results of double blind listening tests showing Audyssey MultiEQ degrading room performance vs doing nothing. On a dime, all the proponents of blind tests became subjectivists defending their personal, sighted, non-controlled observations. You can read the dozen or so pages on this starting here: http://www.avsforum.com/t/1425262/are-audio-companies-all-involved-in-a-huge-conspiracy/840#post_22505809 . Here is part of that post:

So in a test by Harman, Harman found that their room EQ worked better than Audyssey? And that people liked the sound better without Audyssey enabled? The oil companies have funded some climatology studies proving there is no global warming if you'd like to read that, too. LOL
 
#61 ·

Quote:
Originally Posted by cel4145  /t/1438403/audio-media-server/30#post_22636159


I also like to think of these things in terms of opportunity costs. If you are deciding between purchasing an AVR or a cheaper AVR + separate DAC, another consideration is the room correction software. If the more expensive AVR has better room correction software, you'll typically get a worthwhile improvement in SQ. Unlike DAC performance, that's not controversial. For example, most people find that upgrading to a higher level of Audyssey MultiEQ definitely does offer SQ benefits in most rooms.

Thanks for the input. I actually have two MultEQ receivers (one in living room, the other in the bedroom) and am satisfied with the results. I'm sure XT or higher do offer better SQ. I also have some lower end Parasound two-channel stuff and toyed with the idea of DACs and decided against (currently using Marantz as pre-amp and Parasound pre-amp for lps).
 
#62 ·

Quote:
Originally Posted by cel4145  /t/1438403/audio-media-server/30#post_22638131


So in a test by Harman, Harman found that their room EQ worked better than Audyssey? And that people liked the sound better without Audyssey enabled? The oil companies have funded some climatology studies proving there is no global warming if you'd like to read that, too. LOL
I must say with 15 pages of excuses to not believe a published, controlled test like this in the other thread, no one came up with as colorful analogy as you did.
Alas, as most analogies go, they fall apart pretty quickly. Exactly how long you think it will be before the environmentalist lash out with their own data to counter what the oil company research showed? I would think the time would be measured in milliseconds.
. In this case, the research data was presented at AES conference in October 2009. There was no response that came out in 2010, or 2011. And here we are at the end of 2012 and still nothing.


If you read that thread you see that there was a lot more to this research than a listening test. Indeed, its purpose wasn't to crown an EQ system but to determine what system characteristics leads to listeners detecting a positive or negative preference. In that regard, they performed frequency response measurements of each system and using that, they showed why some of the systems performed worse than others. And importantly in this instance, Audyssey lost out to doing no eq at all. Exactly how do you cook a test to generate that kind of result??? Audyssey was competing with doing nothing.


The results also don't point to cooked tests. Two systems performed worse than no EQ but one came very close to Harman's. Why? Because the last system followed the same kind of frequency response measurements that listeners like. Things like smooth frequency response. And a non-flat response. Because of this kind of analysis, the results of the tests are more durable than this just one instance. If a system like Audyssey puts a mid frequency dip, you will hear that if you know what you are listening for. If it brings the bass down, then you will also feel the lack of energy there that you are used to normally hearing. All of this was detailed in excruciating detail in the other thread.


For the purpose of this thread, the point I want to make is that you simply have no controlled, non-sighted listening test to back your recommendation to the other poster. You merely went by your own subjective experience and what you may have heard about others having a positive experience. When presented with controlled tests that show completely opposite data, the reaction is not to try to learn more about why. But to immediately think corruption and invalidity. In what way these excuses any different than an audiophile questioning validity of blind tests of DACs? They, just like you, have a distrust of Arny's of the world or whoever else run these tests and have their version of reasons of the results are no good and again, like you all, want to believe their gut, and personal sighted experiences. Not saying both camps are equally wrong but that the similarity is uncanny.
 
#63 ·

Quote:
Originally Posted by amirm  /t/1438403/audio-media-server/60#post_22641150

I must say with 15 pages of excuses to not believe a published, controlled test like this in the other thread, no one came up with as colorful analogy as you did.
Alas, as most analogies go, they fall apart pretty quickly. Exactly how long you think it will be before the environmentalist lash out with their own data to counter what the oil company research showed?

I just am not interested in reading any research that discredits another company's product any more than I am interested in reading climatology study data debunking global warming funded by the oil companies. Just way too much bias there for the research to be credible. And the lack of response doesn't mean it is credible. Just means no one has responded to it yet.


(And, btw, it's not the "environmentalists" who would counter such research coming from oil companies. This was not a "what if" scenario. The very large majority of research by climatologists has for years countered the few studies funded by oil companies.)
 
#64 ·

Quote:
Originally Posted by amirm  /t/1438403/audio-media-server/60#post_22641150

Quote:
Originally Posted by cel4145  /t/1438403/audio-media-server/30#post_22638131


So in a test by Harman, Harman found that their room EQ worked better than Audyssey? And that people liked the sound better without Audyssey enabled? The oil companies have funded some climatology studies proving there is no global warming if you'd like to read that, too. LOL
I must say with 15 pages of excuses to not believe a published, controlled test like this in the other thread, no one came up with as colorful analogy as you did.

Hmm what alternative universe was that?


I saw an out-of-date, poorly designed test with very limited applicability in this day and age defended tirelessly for 15 pages for some unknown reason by people that have a reputation for wasting everybody's time with such weirdness. ;-)
 
#65 ·
Motherboards have a lot of noises in music playing.

The quality of the DAC's on motherboard is even worse. .

An external (USB) DAC is a whole lot better in noise suppressing and price may vary from $5 to 1,000+. I use $5 ext DAC to play some background music while I am using computer on Study room 2.0 system

I rather play SSD / SD / USB Flash on Hi-Fi DAC or BD /DVD player with USB input . I use OSD control. on TV.

But I enjoy open CD box and load CD on my vintage CD player and 2.0 Hi-Fi system more as the CDs do not wear out like LP .
 
#66 ·

Quote:
Originally Posted by TLCW  /t/1438403/audio-media-server/60#post_22655694


Motherboards have a lot of noises in music playing.

If that is true why is so much commercial music and sound tracks produced on PCs?


That's just it, what you say is not any kind of global rule. Not all motherboards sound the same.
Quote:
The quality of the DAC's on motherboard is even worse. .

Again nothing like a global truth. Many people have PC's with good sound coming off of the motherboards.
Quote:
An external (USB) DAC is a whole lot better in noise suppressing and price may vary from $5 to 1,000+. I use $5 ext DAC to play some background music while I am using computer on Study room 2.0 system

External DACs can work, and you're right they don't have to cost a ton of money. However they have no inherent advantages over all PC systems that have the sound board inside the box or on the system board. Sometimes they are more problematical than other solutions.
 
#67 ·
arnky: I agree that some M/B are better than the others, I came across sound cards ( M/B or even in separate board ) with only a few components for DAC, and external DAC may have a lot more. Furthermore, as long as they are inside the computer , the CPU fan, PS fan(s), the ferrite core etc cause noises / interference. Quite similar to inside many AV Receivers where HF Video processing is shut down for pure / direct 2.0 play back.

Anyway, my main point is : to have digital signal going outside the computer and then use a DAC externally ( even the same chip as the MB ) to give sound for better SQ.
 
#68 ·

Quote:
Originally Posted by TLCW  /t/1438403/audio-media-server/60#post_22665091


arnky: I agree that some M/B are better than the others,

Indeed. The general quality level of onboard sound has been rising in general. System boards intended for the HTPC market often have better sound.
Quote:
I came across sound cards ( M/B or even in separate board ) with only a few components for DAC, and external DAC may have a lot more.

All the parts count means is how highly integrated the sound system is. In general it takes fewer and fewer parts with the more modern chips.
Quote:
Furthermore, as long as they are inside the computer , the CPU fan, PS fan(s), the ferrite core etc cause noises / interference. Quite similar to inside many AV Receivers where HF Video processing is shut down for pure / direct 2.0 play back.

The fans run on DC and use SS commutators so they cause few noise problems. I know of no AVRs that have substantially better noise specs when they are used in a non-video mode. Typically the video processing is on its own card(s). Most of the audio processing is done in the digital domain, anyhow.

Quote:
Anyway, my main point is : to have digital signal going outside the computer and then use a DAC externally ( even the same chip as the MB ) to give sound for better SQ.

Trouble is that a DAC chip always has digital data and clock lines running right up to it. That can't be avoided.


Mixed signal (IOW digital and analog on the same circuit card) circuit design has progressed significantly so having digital and analog circuits in the same box just isn't a problem and hasn't been a problem for years.


Take a CD player. Since the beginning CD players have been primarily digital with only a little bit of analog circuity over in one corner.
 
#70 ·

Quote:
Originally Posted by SAM64  /t/1438403/audio-media-server/60#post_22666518


Who told you that?
I am an electronic engineer and building Windows based commercial computer systems for 30 years.

The CPU cooling fan, The fan inside Power supply, Hard Disk ,.. are coils & moving magnets ( i.e. ferrite core) ,- all motors at their RPM , generate RF.

Put a probe inside a Motherboard you can see from the scope before and after the computer is on.
 
#71 ·

Quote:
Originally Posted by TLCW  /t/1438403/audio-media-server/60#post_22804965

Quote:
Originally Posted by SAM64  /t/1438403/audio-media-server/60#post_22666518


Who told you that?
I am an electronic engineer and building Windows based commercial computer systems for 30 years.

30 years ago was 1983

http://en.wikipedia.org/wiki/Microsoft_Windows


"Microsoft introduced an operating environment named Windows on November 20, 1985."


Fail!


I admit it, I built my first Windows-based system only about 25 years ago, but since then I personally built about 2,000 of them. How about you?
Quote:
The CPU cooling fan, The fan inside Power supply are coils & moving magnets ( i.e. ferrite core) ,- all motors at their RPM , generate RF.

The idea of fans powered by brushless motors generating RF is pretty interesting.

http://forum.orientalmotor.com/viewtopic.php?f=26&t=488


"Q: Which motor exhibits the most electrical magnetic interference/noise between AC motors, brushed DC motors, and brushless motors?


A: If we look at the 3 motor's design, construction, and characteristics, the brushless motor would likely exhibit the least amount of EMI. The bearings of both an AC motor and a brushless motor are the only rotating parts. The brushed motor also has rotating brushes to commutate its windings. The brushes of a brushed motor generate some EMI. The current losses resulting from the inefficiency of an AC motor also generates EMI. The brushless motor is more efficient than AC motors so its current losses are lower, which means less EMI.


In addition, we also need to look at EMI generated by the respective controllers or drivers of these motors as well to make a complete comparison. AC inverters which generate sine waves, like our FE series inverters, will output cleaner noise. Some say some brushless motor system generate more erratic noise since it generates square wave pulses. However, components we have in today's driver designs as well as measures to reduce EMI makes this comparison very difficult. Testing is the best method to find out.

"


So friend, got any tests to back up your excpetional claim?

Quote:
Put a probe inside a Motherboard you can see from the scope before and after the computer is on.

Yeah, but what does that have to do with EMI that you say is allegely generated by fans?


And why is it that the audio interfaces with the best dynamic range are on PC cards that have to sit inside a computer box?
 
#72 ·
I try to explain myself in more details:

After graduation in 1982 Summer in Austin, TX. Then I started selling computers, first IBM PC DOS period packed with my macros for lotus and softwares using dBase II & III then Windows as the platform (when the OS became more stable from 1987). And since then, I had had assembled and sold Desktop / notebook computers of about 300 a year from 1985 to 2000, they were IBM, Dell, HP, Sony, Epson, Fujitsu, Toshiba, Lenovo & Self-Assembles . Then I handled Local Networking & Web -based software systems as project manager. And my only hobbies are AV, Music & DIY audio gears All the people in the computer field whom I know do believe the main unit of a PC is noisy (Noisy fan, video interference) for audio ( CAS) . Also, a lot of threads saying so for many years in knowledge bases . Once , I recalled , back a few years ago, I was looking for the Onkyo PCI sound card, Wavio SE-300PCIE US$200+, a reviewer said he would prefer external over internal sound card more or less repeated what I had said . Also, The shut down of the video circuit in pure audio mode in AVR is for the lesser distortion -not only PS for more headroom but also because of HF interference of the video circuits. The manufacturers ( as what I recall, one is Onkyo) say so for many years til now in their catalog !!!

Bryston says so:
http://hi-fi-avenue.blogspot.hk/2010/12/super-size-your-sonics-with-bryston.html

Furthermore , the air turbulence and vibrations all add to loss in ANALOG stage of amplification in the computer .

There may be some multi-tank missile proof chassis with absolute vibration-free mounts , plus absolute silent fan but ..

I am using Dell Dimension Desktop at Home. I watch and hear you-tube with a External DAC ( USB ) ( 1.5" x 1") . Very clean and clear and with amplified sound much much better than that Dell onboard sound card . It was for US$4.5 in 2011!!!

My DAC is next to my keyboard while the computer is under Desk . The copper shielding of Onkyo PCI sound card may or may not do its work but my CDP is noisy with the variable RCA output though the IR remote chip is shielded by 3M copper film tape. Same circuit external / Internal differ only by the USB interface+ PS + chassis - not much lol!

Anyway, I just want to emphasis: digital signals processing, e.g. computer mixing , studio editing .. ,of course , is all digital,,, is lossless and faultless but the output of a DAC is not audible unless it is amplified to line level .. etc and that analog circuit is subjected to RF frequency , variable/rotating magnetic field interaction, mechanical vibration all add to distortion / Loss . By using USB / coaxial to do DAC outside the computer box is my stand.

p.s. I do see CAS is the trend for future audio. I am DIYing a AK 4396 USB Kit (US$40 + case($6.) +PS( $6.) which is 1 box for all my sources (CD, SACD, DVD Audio, Digital Concerts, Computer Files, Internet Music.. for serious music listening in my system 1. to preamp ...
 
#73 ·
Also:
Quote:
Originally Posted by arnyk  /t/1438403/audio-media-server/60#post_22805208


Yeah, but what does that have to do with EMI that you say is allegely generated by fans?

The EMI is magnetic field, when the analog current pass through magnetic field ,though it is moderate, the EM force acting on the current (electrons) alters its velocity , therefore the current / voltage changes. This account for interference / distortions. If It is a moving magnetic field, the result is worse, The voltage / current is fluctuating from its original values - rather than shifted by a finite offset), by fan RPM cycle,

When digital signal pass through the moderate magnetic field , many error- detection / packet-resend will guard and correct for distortions. But in analog, ( as far as I know), has no means to so do as it is not countable (e.g. parity-check logic).


The other questions " best dynamic range card " , I have not seen the statement and , IMHO, I don't agree. . Shortest linkage ? But decent digital signal cables, say LAN (unshielded), go 50 feet easily in a office without loss. For External / Internal DAC , we are talking 3 - 5 feet for Coaxial & USB LOL.
 
#74 ·

Quote:
Originally Posted by TLCW  /t/1438403/audio-media-server/60#post_22809547


Also:
Quote:
Originally Posted by arnyk  /t/1438403/audio-media-server/60#post_22805208


Yeah, but what does that have to do with EMI that you say is allegely generated by fans?

The EMI is magnetic field, when the analog current pass through magnetic field ,though it is moderate, the EM force acting on the current (electrons) alters its velocity , therefore the current / voltage changes. This account for interference / distortions. If It is a moving magnetic field, the result is worse, The voltage / current is fluctuating from its original values - rather than shifted by a finite offset), by fan RPM cycle,

Obviously not the writing of an EE or any person with adequate training in Electrical Engineering.
Quote:
When digital signal pass through the moderate magnetic field , many error- detection / packet-resend will guard and correct for distortions. But in analog, ( as far as I know), has no means to so do as it is not countable (e.g. parity-check logic).

It is true that when properly implemented digital audio has a great deal of inherent resistance to audible changes during transmission and receiption. However there is no mechanism for retransmission or data in many common digital audio transmission protocols including those used by SP/DIF , TOSLINK and most that are used over USB. Analog signal transmission in noisy contexts is a mature art and even very small signals are commonly transmitted dozens of feet in noise environments with negligible degradation.
Quote:
The other questions " best dynamic range card " , I have not seen the statement and , IMHO, I don't agree.

Speaks to a lack of knowledge of modern audio interface products. A willingness to blithely disagree with well-known facts speaks volumes.
Quote:
Shortest linkage ? But decent digital signal cables, say LAN (unshielded), go 50 feet easily in a office without loss.

The actual distance limit for LAN cables is about 6 times 50 feet or more like 300 feet.

http://en.wikipedia.org/wiki/Category_5_cable


"According to the ANSI/TIA/EIA standard for category 5e copper cable (TIA/EIA 568-5-A[5]), the maximum length for a cable segment is 100 meters (328 feet)."
Quote:
For External / Internal DAC , we are talking 3 - 5 feet for Coaxial & USB LOL.

The maximum length for a standard USB cable is either 9 or 15 feet, not 5 feet:

http://en.wikipedia.org/wiki/Usb


"The USB 1.1 Standard specifies that a standard cable can have a maximum length of 3 meters with devices operating at Low Speed (1.5 Mbit/s), and a maximum length of 5 meters with devices operating at Full Speed (12 Mbit/s).[citation needed]

USB 2.0 provides for a maximum cable length of 5 meters for devices running at Hi Speed (480 Mbit/s)."


The length limit for Coax (SP/DIF) can be 100s of feet depending on the quality of the cable:

http://en.wikipedia.org/wiki/Spdif


Shows maximum lengths ranging from 100 feet to 1,000 feet depending on format under "Hardware Specifications"


The above two posts (72 and 73) slough just about every issue that I raised, and for what little was actually touched on, the answers were all based on nothing but personal speculations and almost completely erroneous.


The little actually said seems to be just as reliable as the initial claim of building Windows goodly numbers of computers several years before MS initially released the product. :-(
 
#75 ·
" Obviously not the writing of an EE or any person with adequate training in Electrical Engineering."


Then, who am I?


You are too Offensive and insulting , This is the most unfriendly 'sharing' site !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


Sorry, so much talking already. PERIOD. I leave the site for good.
 
#76 ·

Quote:
Originally Posted by TLCW  /t/1438403/audio-media-server/60#post_22810399


" Obviously not the writing of an EE or any person with adequate training in Electrical Engineering."


Then, who am I?

I'm talking about what was said.


Here's one very odd statement (of many):


"The EM force acting on the current (electrons) alters its velocity "


Do you seriously believe that external electromagnetic fields alter the velocity of signals or current in a wire?


Furthermore, the current in an electrical wire is different from the speed of the charge carriers (electrons) in the wire.

http://en.wikipedia.org/wiki/Speed_of_electricity


"The speed at which energy or signals travel down a cable is actually the speed of the electromagnetic wave, not the movement of electrons."


When the applied voltage is alternating current (such as an audio signal) the electron's velocity is zero.


"When a DC voltage is applied the electrons will increase in speed proportional to the strength of the electric field. These speeds are on the order of millimeters per hour."


If an person doesn't learn this in high school physics, they surely learn it in first year college physics, a universal prerequisite for any EE.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top