Help for a newbie

[mville]

Re: Help for a newbie

And such errors will be OBVIOUS (things won't work). They will NOT be "subtle differences in sound quality, soundstage, etc."

Yes, thanks garym for making that clear.

Any errors that occur will only impact on the ability to transfer digital data i.e. will not work, and DO NOT impact on audio quality at all.

[BrodyBoy]

Re: Help for a newbie

Jocar37: garym and mville are two of the best contributors in this forum, and once again, they've offered excellent advice and information. You can't do better than a careful read of their conversation on this matter. Some particularly cogent "pearls of wisdom":

Audiophiles have never recovered from the move to digital and continually try to use concepts/issues that *were* an issue with analog systems in the context of digital music.

I've never heard this phenomenon stated better than that sentence. It really is the heart of the problem with this whole false "debate".....analog and digital transmission are fundamentally different. Analog concepts simply do not apply to digital signals, yet there remains an audiophile contingent that simply does not understand the difference. Their heart's in the right place, their basic science isn't. And some very unscrupulous companies are thrilled to take advantage of that.

I personally find that bluejeans cables are high quality, well constructed, fairly priced cables. I think about 99% of all my cables are purchased from bluejean cables.

You cannot buy better digital cables than Blue Jeans, IMO. (Though you can certainly buy prettier, fancier, more expensive ones....) If you read through some of the articles on their website, it's obvious that they're extremely knowledgeable about the factors that actually do matter in cable construction and performance, for both analog and digital. (And they don't conflate the two to confuse buyers.) Where impedance can be an issue, they focus on impedance. Where signal loss can be an issue, they focus on signal loss. Same with interference, connector limitations, etc. No snake oil, just reality-based cable construction.

Then again, there is nothing wrong with you going whole hog into the military grade milled aluminum components, $1000 ethernet and USB cables, and a mistaken idea that a bit-perfect WAV can sound better than a bit-perfect FLAC. It's only a hobby and its your money of course. And independent of all this, everyone needs bit-perfect lossless rips and ability to convert from one codec to another, and dbpa is an excellent source of these tools.

Exactly! It all has to start with perfect digital files. To me, dBp and EAC are the two best programs for ripping perfect files, but I feel dBp "wins" by being the easier-to-use option.

Ethernet and USB cables are transferring digital data and not analog audio. Ethernet/USB cables will either work or not work.

The digital data is in the form of 1's and 0's. The devices sending and receiving this data will confirm that the data is being sent/received correctly (software/firmware handshaking). If the data is not sent/received correctly, errors occur.

Yup...nothing but 1's and 0's. I would simply add that your point applies not just to ethernet and USB cables, but virtually every kind of digital cable. So jocar37, as regards your earlier question (to garym) about other kinds of cables, the answer is YES if it is a digital transmission cable. All of these cables....HDMI, digital coax, optical, etc...are simply carrying bitstreams of 1's and 0's.

The only factors that can possibly differentiate digital cables are those that cause failure to deliver the bitsream successfully...it's a pass/fail system, so to speak. Digital cables simply cannot impart audio qualities like "warmth" or "harshness" or "clarity," nor can they impact things like "sound stage," "sound floor," "noise," or "depth." Those are all concepts from the analog world, where equipment and cable designers have forever tried to "massage" the signal to manipulate the output. But this is not possible with digital bitstream transmission. If a cable company even hints that their digital cables have these qualities, they are selling snake oil.

[jocar37]

Re: Help for a newbie

It seems like almost everything I've been reading over the last several months needs to be revisited, or even disregarded.

So all bit perfect is created equal, and someone who believes that the same source file ripped as both WAV and FLAC sound different is just fooling themselves? I accept the premise, but I will probably want to test it myself (likely per Foobar"s ABX as suggested). But if I accept this premise, is there any reason why someone would want to rip to WAV instead of FLAC? Uncompressed FLAC instead of "regular" FLAC? (I trust my understanding that there are such different animals is accurate - I learned it from dbp.)

Also if I understand correctly that any two properly manufactured ethernet cables, usb cables, coax cables, digital cables, etc. are the same for purposes of transmitting digital signal regardless of any manufacturer's claims to have added a "secret sauce," are there any considerations in selecting hardware or software?

For instance, if bits are bits, do you give any credence to the discussion of how different DACs process the signal more "musically," "analytically," etc.? If you do believe different DACs sound different, do you attribute any of those differences to whether they use the same or different DAC chips, or to what ancillary circuitry is in the box? If you find it differs based upon which chip is used but the bit stream is processed cleanly, how do you account for the differences? If you find differences based upon other parts of the circuitry?

I'm not trying to be a smart ass about any of this. I'm really interested in understanding this stuff - particularly as I'm looking at buying a new DAC shortly.

Thanks!

[BrodyBoy]

Re: Help for a newbie

It seems like almost everything I've been reading over the last several months needs to be revisited, or even disregarded.

Well, again, it's about a difference between analog and digital. Where you have been reading about analog signals, there is more substance to the discussion. The problem is just in throwing digital cables into the same boat.

So all bit perfect is created equal, and someone who believes that the same source file ripped as both WAV and FLAC sound different is just fooling themselves? I accept the premise, but I will probably want to test it myself (likely per Foobar"s ABX as suggested). But if I accept this premise, is there any reason why someone would want to rip to WAV instead of FLAC? Uncompressed FLAC instead of "regular" FLAC? (I trust my understanding that there are such different animals is accurate - I learned it from dbp.)

Some "purists" choose WAV because they are suspicious of the compression that other lossless codecs apply. But they contain the exact same digital data....compression doesn't impact that at all. I think FLAC and other codecs are preferable because they are better supported and much easier to tag. There's no qualitative difference between compressed and uncompressed FLAC. Compression just slows processing time a bit and creates smaller file sizes.

Also if I understand correctly that any two properly manufactured ethernet cables, usb cables, coax cables, digital cables, etc. are the same for purposes of transmitting digital signal regardless of any manufacturer's claims to have added a "secret sauce," are there any considerations in selecting hardware or software?

For instance, if bits are bits, do you give any credence to the discussion of how different DACs process the signal more "musically," "analytically," etc.? If you do believe different DACs sound different, do you attribute any of those differences to whether they use the same or different DAC chips, or to what ancillary circuitry is in the box? If you find it differs based upon which chip is used but the bit stream is processed cleanly, how do you account for the differences? If you find differences based upon other parts of the circuitry?

I'm not trying to be a smart ass about any of this. I'm really interested in understanding this stuff - particularly as I'm looking at buying a new DAC shortly.

Thanks!

Hardware matters a lot. And I don't think you're being a smart ass, BTW....I appreciate your open-mindedness and willingness to ask your questions.

IMO, the two most important components in a digital music system are the DAC in the playback hardware, and the actual speakers you're playing it through. A DAC takes that digital bitstream we've been talking about and converts it back into an analog signal. Both the quality and the "tuning" of the DAC can make a big difference in the audio output. My suggestion is to put your serious money into these kinds of components, as they're the ones that'll make a difference.

[jocar37]

Re: Help for a newbie

I appreciate your open-mindedness and willingness to ask your questions.

And I appreciate everyone's willingness to lend me their expertise.

IMO, the two most important components in a digital music system are the DAC in the playback hardware, and the actual speakers you're playing it through. A DAC takes that digital bitstream we've been talking about and converts it back into an analog signal. Both the quality and the "tuning" of the DAC can make a big difference in the audio output. My suggestion is to put your serious money into these kinds of components, as they're the ones that'll make a difference.

I would agree about the DAC and the speakers being the most important. I'm quite content with the speaker part of the equation in my system. But the DAC issue I'm really struggling with. I understand the basics of what a DAC does. But, again, if bits are bits, and if you presume a well designed and manufactured DAC chip processes cleanly, do you guys think there is/can be a difference between how a Sabre, Burr Brown, Cirrus or any other quality DAC chip sounds? What other aspects of the DAC circuitry, if any, do you feel impacts sound? I'm sure you don't mean that just because a component costs serious money means it's a quality component. If a $1000 USB cable is snake oil, I have to be skeptical that a $5000 DAC is superior to a $500 one just because it costs $5000. So to be sure I'm buying one that will make a difference, what should I look for?

This is far from a hypothetical. I've been looking at several DACs. One is the Marantz HD DAC-1 which has been very well reviewed and costs $800. Two others are the Exasound e22 and e28, which have gotten some spectacular reviews but cost 4 times as much. How do I rely on the reviews if so much of the audio press is not credible? And if I can't rely on the press, how do I judge whether the Exasounds are vastly superior to the Marantz by assessing them on nothing other than their vastly disparate price points? If you guys can help me sort that out, that would be phenomenal!!

[BrodyBoy]

Re: Help for a newbie

I would agree about the DAC and the speakers being the most important. I'm quite content with the speaker part of the equation in my system. But the DAC issue I'm really struggling with. I understand the basics of what a DAC does. But, again, if bits are bits, and if you presume a well designed and manufactured DAC chip processes cleanly, do you guys think there is/can be a difference between how a Sabre, Burr Brown, Cirrus or any other quality DAC chip sounds? What other aspects of the DAC circuitry, if any, do you feel impacts sound? I'm sure you don't mean that just because a component costs serious money means it's a quality component. If a $1000 USB cable is snake oil, I have to be skeptical that a $5000 DAC is superior to a $500 one just because it costs $5000. So to be sure I'm buying one that will make a difference, what should I look for?

Oops, I think I expressed myself poorly...I should have more clear. When I said "spend your serious money" on the hardware end, especially speakers and DAC, I didn't mean to imply you should spend huge $$$ on some fancy, standalone DAC. I meant, more generally, that your playback hardware...which includes the DAC somewhere in the chain....and the output hardware (speakers and/or headphones) are most determinate in your system "sound." Not cables. This isn't really the place for specific hardware discussion or review, but I'll just say that I personally think there's a point of rapidly-diminishing returns with products like standalone DACs. That is, the performance difference between the DAC in my iPod and the one in my A/V processor is noticeable. But adding a very expensive DAC to my system may yield a subtle difference, at best, from what my processor already provides (all else being equal). And the difference may not even be an "improvement."

I honestly think very few of us have the equipment (or the ears) to discern whatever differences may exist between the $500 and $5000 DACs.

This is far from a hypothetical. I've been looking at several DACs. One is the Marantz HD DAC-1 which has been very well reviewed and costs $800. Two others are the Exasound e22 and e28, which have gotten some spectacular reviews but cost 4 times as much. How do I rely on the reviews if so much of the audio press is not credible? And if I can't rely on the press, how do I judge whether the Exasounds are vastly superior to the Marantz by assessing them on nothing other than their vastly disparate price points? If you guys can help me sort that out, that would be phenomenal!!

I wouldn't rely on the reviews. Frankly, I'm very skeptical of what the so-called "experts" have to say about subjective matters like sound. They can describe features, UI, build quality, etc, and that's all useful info, but only I can know what sounds good to me. (Plus, I suspect reviewers can't help but be influenced by their relationships with manufacturers, who provide the review equipment and ad revenues.)

Go back to what you've said in several other posts....rely on your ears. Unfortunately, the small, independent audio shops where we can go compare these kinds of products have become something of an endangered species. Sometimes, the only option is to order the gear and test it in-home, making sure you have a liberal return policy. You haven't mentioned what you're currently using. But I'd be pretty shocked if double-blind testing revealed those $3-4K DACs to sound much if any different than the Marantz if you could try them all in your system...and you'd probably be just as likely to prefer the Marantz.

Just get what sounds good to you. And don't assume a linear between cost and sonic performance.

[garym]

Re: Help for a newbie

Jocar37: garym and mville are two of the best contributors in this forum, and once again, they've offered excellent advice and information. You can't do better than a careful read of their conversation on this matter.

Thanks. BrodyBoy provides thoughtful and detailed explanations himself. (by the way, we don't all agree on everything around this forum, we use different codecs, some use multiencoder some don't, our libraries are organized in different ways, we manage our tags differently, brodyboy uses sonos and I use squeezeboxes, etc. But all those things are just a matter of taste and user preference. Bit perfect rips are not a subject that varies with "taste".)

[garym]

Re: Help for a newbie

It seems like almost everything I've been reading over the last several months needs to be revisited, or even disregarded.

So all bit perfect is created equal, and someone who believes that the same source file ripped as both WAV and FLAC sound different is just fooling themselves? I accept the premise, but I will probably want to test it myself (likely per Foobar"s ABX as suggested). But if I accept this premise, is there any reason why someone would want to rip to WAV instead of FLAC? Uncompressed FLAC instead of "regular" FLAC? (I trust my understanding that there are such different animals is accurate - I learned it from dbp.)

Also if I understand correctly that any two properly manufactured ethernet cables, usb cables, coax cables, digital cables, etc. are the same for purposes of transmitting digital signal regardless of any manufacturer's claims to have added a "secret sauce," are there any considerations in selecting hardware or software?

For instance, if bits are bits, do you give any credence to the discussion of how different DACs process the signal more "musically," "analytically," etc.? If you do believe different DACs sound different, do you attribute any of those differences to whether they use the same or different DAC chips, or to what ancillary circuitry is in the box? If you find it differs based upon which chip is used but the bit stream is processed cleanly, how do you account for the differences? If you find differences based upon other parts of the circuitry?

I'm not trying to be a smart ass about any of this. I'm really interested in understanding this stuff - particularly as I'm looking at buying a new DAC shortly.

Thanks!

BrodyBoy has already addressed your comments well, but I'll add my 2 cents on your questions. And first, I certainly don't think you're being a "smart ass" and I also hope you don't think I'm trying to be some holier than thou "internet expert" that is trying to be argumentative. Of course we're all here because we want quality digital music (otherwise we'd be ripping our CDs with iTunes, listening on earbuds, and never giving any of this stuff a single thought!)

Re your comments:

1. WAV vs FLAC vs Uncompressed FLAC.
Any lossless file will decode to be bitperfect back to the orginal CD (assuming the file was created properly to begin with). There is no question about this as it can be easily confirmed. There's a subset of users out there that believe WAV is better because there is no "compression" applied and that somehow the decoding of the FLAC during the playback process makes the Server or Player "work harder" and affects the sound quality. The problem with this idea is that (1) if the server or player can't deal with this small level of processing, you'll get errors (NOT subtle sound quality differences) and (2) any modern server/player that can't decode a lossless file in preparing for playback is broken. It's a simple task long ago perfected.

There's the complete Wacko camp that even thinks they can detect sound quality differences when a WAV file is copied to another hardddrive and played from there. Yes, they actually believe, and will argue with you for days, that the bitperfect copy of a WAV file (which they fully agree is a bit perfect copy) will sound different because of something those "zeros and ones" picked up in the simple file copy process.)

Then there's the more reasonable camp, that wouldn't believe the above, but they think that perhaps the decoding process adds "noise" to the server/player that then gets transferred to the ultimate analog audio output. There is at least an engineering possibility of this, but I've not seen any rigorous tests that can document this (but I've seen lots of rigorous tests that document that differences can NOT be detected between WAV and FLAC or other lossless files). I'm sure one could set up a test where a FLAC file was being decoded by some really low power processor in a really badly constructed player that was practically designed to pick up electrical noise and perhaps find a problem. But I suspect this would be very hard to do, as even the crappiest smart phone you could buy today has more than sufficient processing power and construction quality to decode a lossless file properly).

The FLAC compressed (0-8) vs FLAC uncompressed is a slight variation on the WAV vs FLAC argument. Lossless = Lossless, and this is easily confirmed with decoding any lossless file and comparing the output to any other file (WAV). But again, some believe the decoding process might add "noise" or something because of the effort of the server or player in decoding. The 0-8 or uncompressed only speaks to the FILE SIZE of the lossless file (not whether it is lossless). Some believe the server/player has to "work harder" with more compressed FLAC files and could create problems. The reality is that decoding a FLAC file (even if the most compressed at "8") doesn't take any more work than one compressed at "0". The extra work is in the initial ENCODING of the file. It does take more work (and time) to encode a FLAC at "8" than at "0" or uncompressed. But that's a one time activity that has nothing to do with playback of the file (only the creation of the file).

To be fair, I do know of one case where a specific player (Squeezebox Transporter) had some issues with playing a hi-res (24/96) flac file compressed at "8". This turned out to be a firmware problem and it was fixed with a firmware update. This only affected hi-res, and it wasn't a problem that affected sound quality or "noise", it made the tracks unplayable.

I have no actual knowledge of this, but I suspect Spoon created the FLAC "uncompressed" option to appeal to the "we want to use WAV only" folks and they were satisfied with the idea that this would be essentially a WAV file "wrapped" in a FLAC container, with the benefits of FLAC files (discussed later below). If the WAV vs FLAC debate is something that keeps you from sleeping at night, then I'd suggest you use the FLAC uncompressed option.

Also to be fair, there is a basis for the WAV only users to be fixated on WAV. In the olden days of digital audio, we didn't have FLAC files, etc. In those days, we had mp3 files (and sometimes really crappy mp3 files). So people who really cared about their music wanted something better and WAV was essentially the only lossless files ("Shorten" came along and was the first compressed lossless file I ever learned about). So early on, it was important to use WAV files. But those days have long passed. As a comparison, in the context of automobiles, I could have had discussions back in the early 1970s regarding the best quality engine performance with the use of certain "points" settings and carburetor adjustments/types, etc. That's a pretty silly discussion in 2015 since no engine uses either points or carburetors. But even today I get into some discussions with oldtimers regarding how their (memories) of manually playing around with those old school engine adjustments is so much better than a computer chip managed super efficient fuel system. Essentially they are still stuck in the "analog" days.

Lossless files have some concrete benefits way beyond taking up less space (a factor I could care less about). First, there is a standard metadata tag system (and there is not for wav files, which leads to lots of headaches when users find out that their meticulously tagged wav files show up in some new server/player as if they dont' have tags). Second, and often overlooked in this discussion, is the fact that all FLAC files have checksum values embedded in the file by default. This means that, for example, I could copy 100,000 FLAC files over to a new harddrive and when done I can select those files as one batch, make a couple of mouse clicks (using any number of programs, including dbpa "covert to TEST CONVERSION") and relatively quickly do a complete test of whether any of those files are corrupted. One can't do this with WAV files.

2. DAC quality. BrodyBoy addressed this well and I agree with his comments. Yes, here there *can* be differences in audio. Because we are now back in the ANALOG realm (with the DAC converting the digital back to analog). The chip matters some, but all the other stuff (the build) in the processing chain start mattering (filtering, etc.). Keep in mind that there are some very badly designed DACs. Unfortunately, some of the worst offenders are so called NOS DACs that are very expensive and designed for the "audiophile" market. I've seen tests that show how some of these expensive audiophile DACs are outperformed by the DAC in a $15 cheap CD player. But DACs do matter. Like a lot of other things in audio, we've reached the point where one shouldn't have to spend a fortune to get a quality DAC as they have gotten better over the last 20 years (My first CD player in the mid-1980s cost over $1,000 I recall and any $20 CD player purchased at wal-mart in 1995 would have been better, including a better DAC.). DAC chips themselves are very cheap (a few bucks), but the build, the filters, the wiring, the quality of the components, etc. matter (and remember, much of this is now in the *analog" realm).

I only own one external DAC. An older "Benchmark DAC I". I bought it years ago. It was about $2000. Very high quality build and very well thought of at the time (brand is still very well thought of). I'm sure there are much, much cheaper DACs today that are just as good. I've double blind tested the Benchmark vs the built in DAC in my $300 Squeezebox Touch player in a good system and with great difficulty could identify very subtle differences, but the problem was I couldn't really decide which I liked better. At that point I should have sold the Benchmark DAC. But I like it, I like the fact that it has "Balanced Analog Outputs" that I like to use in feeding my preamp (vs the RCA unbalanced analog outs of the TOUCH). (And by the way, I like the balanced connections not becuase of "subtle sound quality" but related to avoiding potential ground loops and also the way my preamp works in terms of "not touching" the audio coming in through the balanced inputs (it travels through a different path that avoids the path the unbalanced inputs travel that includes bass/treble adjustments....that is, the balanced inputs have a more direct path to the ultimate amplifier).

Anyhow, sorry for the rambling long message, but just wanted to get some thoughts written down on this subject.

[jocar37]

Re: Help for a newbie

First of all, I want to say that I really appreciate the comprehensive and reasonable manner in which you guys have responded to my questions.

For at least the immediate and even intermediate future, my plan is to have all my music in digital format. I have some OLLLLDDDDDDD albums that may not even be in listenablecondition any more, it's been so long since i listened to them, and don't have a good turntable. So the analog concerns shouldn't impact my decisions.

I agree that the recording and mastering process is the most critical. Probably why I liked the XRCD of Soul Station better than the HDTracks version. I have a friend here outside of Philly who does some amazing recordings in his boutique studio - strictly Redbook, but exceptional sound. If you want to check it out: http://www.the-music-centre.com/reco...io/discography.

Still I expect the DSD and DXD catalogs to expand and improve over the next few years and I want to be in a position to try them. The DAC is an issue for me is because I want to explore the expanding choices of DSD and DXD. Otherwise, I'd be okay with sticking with my Oppo BDP103 and my Squeezebox Touch. I looked seriously at Benchmark (even before seeing it reviewed today in theaudiocritic.com), but they don't currently support these formats either. Perhaps those formats in some instances might be more snake oil, but I expect that, like with XRCD, proper attention to the entire production chain can result in a superior product and that this will happen as more people get into recording for them. So do you guys have any other current resources you would recommend as being more reliable than the audio hype printed by the usual suspects?

[schmidj]

Re: Help for a newbie

Gary,

Excellent material. I will make a few points.

The analog side is much more important and subject to differences than the digital side. That said, there can be software/firmware errors affecting the digital side. Most will produce gross errors (won't play, loud noises, etc.) some may be more subtle. However, as long as you are in the digital domain, you can test for errors by the use of checksums, a mathematically calculated number based on the bits in the (audio) data. The chances of two files having different data and the same checksum are microscopic, one in a billion or more. You are much more likely to be struck by lightning when you walk out your door on a clear day than to have two different files with the same checksum. Accuraterip is based on checksums.

When I worked for ABC, our lab found some subtle, and not so subtle, issues with digital items when testing was done. One of the more common was "time" shifts/latency between the channels of multi channel devices. Not an issue on the digital side as long as it is a stereo or other multichannel file not decoded within the box but can be an issue if the channels are handled separately in the software. A checksum test of the input and output files will uncover this, as long as no other processing is done inside the box. If the box "processes" the audio, changes "volume", limits or compresses, has an equalizer, etc, then the checksum approach will not work, as the audio has been changed and the bits will be different. More sophisticated tests will be needed.

Another misunderstood topic, jitter. In the digital realm, you can have a lot of jitter (an unstable clock) and it is not an issue until it gets so bad that the bits actually get messed up, a device gets a bit error. Not subtle, you will probably get a pop or click, or a lot of them, often quite loud. HOWEVER, when you convert from digital to analog, (and analog to digital) then the jitter is critical, as the jitter frequency modulates the analog audio. The human ear is quite sensitive to this distortion. Much of the issue in the early days of CDs and digital audio had to do with excess jitter, and it can still be an issue today.

Jitter is an issue in DACs, but not in USB cables. The USB cable either works, or doesn't. (or works intermittently, an issue I've seen too often with USB3 connectors) It's simply carrying bits from point a to point b.

The DAC is critical, although as Gary said, modern DAC chips are much better. The analog circuitry following the actual DAC chip is also critical, as is the clock recovery necessary to time the DAC and its analog output. This is where the jitter is an issue. The clock needs to be accurate to recover the bits without error, but stable (no jitter) even if the incoming digital stream has jitter. Historically not easy to do, but well understood now. The Benchmark DAC you have is an early good DAC, ABC used many of that model in its early digital plant after extensive testing and evaluation. It is still considered a very good DAC.

You mention speakers. No two speakers sound the same. The choice of speaker involves the taste of the listener, and the room acoustics. The output stage design of the amplifier and the connecting cable also affect the sound. Modern solid state amplifiers not much of an issue, vacuum tube amplifiers much more so. The connecting cable affects the sound of analog speakers, it adds impedance which among other things affects the damping, and therefore the distortion from the speaker. Now, you really don't have to go out and buy 20 dollar a foot "audiophile" speaker cable, go to Home Depot and buy 14 gauge (for short runs) or 12 gauge (for longer runs) "zip" cord, the difference from the 20 dollar a foot stuff is so subtle you'll never figure which is which. Don't use the cheap 20 gauge thin speaker cable, you'll get what you deserve.

This is where powered speakers, including "digital" speakers may shine. Not seen so often in consumer stuff (except as bluetooth/wifi "wireless" speakers, which may have their own set of issues, the bluetooth ones I believe use bitrate compression, read MP3 or such). Putting the amplifier and the speaker in the same box gets rid of the speaker cable issue. The line level or digital cable from the receiver or playback device has very low losses, if the output impedance of the sending end is low. Therefore, what the speaker gets is very close (or for digital, identical) to what the sending device puts out. Also, the designer/manufacturer has complete control over the performance of the speaker/cable/amplifier system and can design for better performance with tighter tolerances. ABC TV has for some years gone to amplified (and more recently "digital") speakers such as made by Genelec, and now others in all its control rooms.

Now some psycho-acoustics. (this is where the A-B-X tests come in, with some caveats. Louder, even by a fraction of a dB will almost always sound "better" all else being equal. Many tests have confirmed this. More bass, particularly at lower listening levels, will sound better, almost all of us LOVE bass, way beyond what is flat frequency response. Part of this is due to the frequency response of the human ear, which varies with loudness. At low listening levels, you need more bass (and to a lesser degree treble) for a signal to sound the same as at louder listening levels (Google "Fletcher-Munson Curves") Also, as you age, your hearing deteriorates more at the extremes than the mid frequencies, particularly at the high end. Receivers used to have "loudness" switches (and some now have DSP settings) which boost the bass (and sometimes the treble) when the volume is turned down.

People with hearing problems sometimes can hear artifacts and deficiencies those with better hearing cannot. What you actually hear is controlled to a good degree by "masking", the inability to hear lower level sound close in frequency to louder sound. If your hearing is messed up, the masking works differently. Much of the "lossy" compression of audio works by throwing out what you presumably can't hear due to masking. If your masking works differently (or you subsequently process the audio to change the relationship between the loud and nearby soft audio) you may "break" the compression and hear the difference in the lossy compression.

Enough for now...

[garym]

Re: Help for a newbie

schmidj - Excellent stuff! Thanks for contributing, and in particular providing the more technical information.

edit:

"You are much more likely to be struck by lightning when you walk out your door on a clear day than to have two different files with the same checksum."

I suspect the odds are greater that you will INDEPENDENTLY be struck by lightning TWICE in the same day at two different locations than finding two files that are not digitally identical but have the same checksum values!