[NewSc2]

inspired from this site:

http://users.belgacom.net/gc247244/index.html

(click on the "quality" tab on the side to get to the article i'm referring to - stupid site won't link properly)

that concluded that with mp3's encoded with LAME at 256kbps the audible difference between mp3's and CD's were impossible to tell apart, even when using high-quality equipment such as the Sennheiser Orpheus and B&W Naultilus 803 + Marantz CD14 CD player.

I don't know the details on how this DBT was done, but I'm assuming they played both mp3's and CD's using the same outputs (both on headphones and both on the B&W setup). If this test was tested correctly, then what would be the motivation of getting a good CD player if 256kbps MP3's sounds exactly the same as CD's even with these expensive setups?

Currently, since my primary source (my xbox) is not with me, I've been playing music through my computer's TB Santa Cruz outputted to my Denon 1802/Swan Diva 4.1/R3 system and through the TB Santa Cruz/Denon combo to my HD580's (I need a better TV before I plop down money for a headphone amp). Although I have not done an A/B or double-blind test, I have not really noticed much difference between my sources, and after researching a bit around, there seems that nothing under $150 will significantly improve the sound, but after reading this article, if I can't tell the difference between a CD and a 256kbps encoded MP3, why even bother with an expensive CD player and why not just stay with my MP3's through computer out? (Or just get a better sound card instead of CD player)

 

[Eagle_Driver]

Oh, yeah, but practically, there is a noticeable difference in sound quality between a consumer soundcard and a good mid-fi component CDP. Most consumer soundcards - including the TBSC - suck compared to a separate CDP in their analog-output electronics. And you'll have to spend an astronomical amount of $$$ (say, at least double that of a comparably-performing CDP) just to get a soundcard that sounds as good as an average component CDP at its analog audio output.

 

[Zin_Ramu]

I have done some DBT on MP3 versus CD in the past with my DVD player (sony NS755v). I could not discern the difference between MP3 and WAV with statical signifigance, at -APS encoding level (VBR with avg. bit rate around 200). Corda HA-1 and HD600 were used for tests.

So while I agree in general that soundcards will not perform at the same level of a dedicated CD player, with the all the new players coming out supporting MP3, you can get very good quality from MP3s and to my ears equaling the level CD performance.

However I imagine when you go beyond an entry-level player like my Sony, the difference may become more apparent, but I haven't been able to test this yet.

Zin

 

[zowie]

Quote:

Originally posted by NewSc2 If this test was tested correctly, then what would be the motivation of getting a good CD player if 256kbps MP3's sounds exactly the same as CD's even with these expensive setups? [. . .] if I can't tell the difference between a CD and a 256kbps encoded MP3, why even bother with an expensive CD player and why not just stay with my MP3's through computer out?

I can understand one not having a preference, but if they sound exactly the same, or virtually so, then that means the playback equipment is not revealing enough. Two different mfg's $1000 CDP's sound noticeably different, although not necessarily better and worse, on a high end stereo.

Eagle Driver makes a very good point. I'd add to that:
1. It's a big bother to convert a large CD collection to MP3.
2. You'd still probably want to store the CDs for the inserts or eventual trade in (big waste of value to keep the inserts and dump the original disc).
3. Playback in factroy car stereos.
4. Remote control.

 

[aeberbach]

Eagle_Driver - perhaps, but you haven't considered the stereolink or the USB converters available from xitech.com. The xitech ones are around $40 and that's a good 20-bit DAC.

Here's another great toy:
http://slimdevices.com/

Once you have all the MP3s encoded and served from a computer there's no more CD changing, ever. It works just like a CD player with a remote but with a better display than most CDs. I'm really thinking seriously about getting this one since I already have all my CDs encoded (30G).

(With the Xbox Live I need to get ethernet into the living room anyway)

 

[NewportGeek]

first off, CD's sound better than MP3's. Period.

Here are some (serious) holes in their "test".

1: They don't list the acutal CD's they used. Just various "rock and pop." These cd's could be poorly mastered, or contain music that doesn't fill the full spectrum of sound frequencys at any given moment (like a full orchestra would do.) MP3s fair well with single instrument sound. Its when they are pressed to fill the entire spectrum simultaniously that there lack of bandwidth is revealed. This problem can be addressed using varible bitrate encoding, but they didn't use and VBE for their test.

2: They use a mac to decode. Mac's interpolate to the full 16 bit 44.1 khz sample rate when decoding mp3s. This is essentially digital upsampling. While it theorectically doesn't provide any increase in sound quality, it does increase the audiability of certian sounds. This is just like oversampling a cd using a dac.

3: They use a tube amp for music playback. The delayed frequency response associated with good tube amps serves as a buffer to soften the coarse sound MP3's provide. Think about it: if you want to push you're brand-new digital format, why would you use an amp based on 80-year-old analog circutry? Simply because any respectable solid state amp would have exposed their MP3's for what they are; lossy.

I've spent alot of my own time looking into mp3 quality encoding. The bottom line is, bits are bits. Anyway you look at it, mp3's are a form of compression; and a lossy one at that.

No one ever says that when you compress and decompress and MP3 you get your original wav back. So you know at least some of you bits, and as it turns out, ALOT of bits (and consequently your fidelity) are going out the window.


CD AUDIO vs. MP3 Audio
------------------
16 bits * 44100 samples/sec * 2 channels =

1,411,200 bits /sec

an mp3 at 256kps is exatly that. 256 kilo bits per second =

256,000 bits / sec

256,000 / 1,411,200 = 0.1814, or 18%

So your mp3 will contain less that 1/5 the bits of the original wav.

think about your 128 kbps mp3s, they score less than 10%.

MP3s are a great format. But if you are the way of the mp3s.

-JT

 

[kerelybonto]

NewportGeek makes some good points about possible problems with the test. Using tubed equipment was just stupid. However, to answer the original question: Quote:

... what would be the motivation of getting a good CD player if 256kbps MP3's sounds exactly the same as CD's even with these expensive setups?

You've grossly misinterpreted the test. In the test, the sample MP3 files were burned to CD and played back in the same system as the original CDs. In other words, the original CD audio was encoded to MP3, then decoded and burned back to CD in CD audio format (WAV equivalent). The test would be obviously invalid if the MP3s were played back on a computer system and the CDs played back on the thousands of dollars worth of high-fidelity audio equipment listed. Not to mention that the results would have been exactly opposite.

Also keep in mind that all digital audio, including CD audio, is itself a lossy format. Lots of audiophiles claim that analog vinyl recording are much better than CDs. I've never been able to compare CD audio to a vinyl setup that was good enough to get past the problems of that format that usually make it distinguishable from CD, but the differences between SACD and CD are pretty apparent to me on many recordings. (Of course, it's debatable whether that's due to differences in the mastering process or the actual audio stream, but ...)

kerely

 

[JaZZ]

With my SB Live Platinum I can hear a tiny difference between Wave and 256 kbps MP3 with very critical recordings, and definitely none if the rate is 320 kbps. Using the SB's headphone out or the EMP.

That doesn't necessarily mean this would be the case with better digital and analog electronics. Soon I will own a Bel Canto DAC2 which is a bit more «transportable» than my currently defective Theta, so i'll try it with that external DAC. I doubt it will be the same.

 

[aeberbach]

No, MP3s are often indistinguishable from CDs.

Quote:

1: They don't list the acutal CD's they used.

It hardly matters. The test is whether one sounds different to the other. Even distortion sounds different when it is replayed, distorted. Certainly MP3 "artifacts" would be apparent if they existed.

Quote:

They use a mac to decode. Mac's interpolate to the full 16 bit 44.1 khz sample rate

I doubt this is true for every MP3 encoder available for a Mac. But if it is that's still a MP3. You seem to be saying that MP3s encoded a certain way don't count.

Quote:

3: They use a tube amp for music playback.

They use an Orpheus - tubes, true enough, but if anyone has said that the Orpheus is a softener I've never seen that review. I've always read that the Orpheus is as detailed as it gets without emphasizing any particular range of frequencies.

But the Orpheus was only one system used. In the same test they also used the following:
B&W Nautilus 803, Marantz CD14 with amp PM14 (Straightwire Pro cabling and extra's) [DM30000- so bit more than $15000]
I know you would have read the article before saying it was all wrong. What's wrong with that system?

If you're really looking for quality the only thing that counts is what you hear. If you don't hear a difference then nothing else matters. If you do hear a difference it's probably time to look at the encoding process and whether you're playing both sources with the same equipment. I use K1000s and hear no difference through the Grace 901 when both CD and MP3 are played through the Xitel 20-bit USB connector. How much more detailed can it get?

Quote:

Anyway you look at it, mp3's are a form of compression; and a lossy one at that.

Nobody ever disputed that. You lose some bits but if they were redundant and inaudible to begin with they didn't matter. If MP3 existed way back when this is the way all CDs would be recorded.

 

[JaZZ]

JPEG is data reduction, too! Nevertheless I haven't ever seen a difference between a TIFF picture and the JPEG equivalent as long as the compression didn't exceed 1:5. Maybe some see it... theoretically it does exist. That said I hear a very slight difference at 256, but not at 320 kbps (= 1:5.5 and 1:4.5) – well, from a low-fi soundcard.

 

[kerelybonto]

If you guys can hear the difference between CD audio and 256kbps MP3 files on your soundcards ... well, let me know which soundcard you're using and I'll buy the design and start selling them for $20k a pop. Seriously, it should be impossible to tell the difference from a soundcard.

JaZZ, good analogy with the JPEG and TIFF. Know why you don't see a difference? -- because your screen doesn't allow you to. Print that stuff out on a photo-quality (or probably even a just a good-quality) printer and it'll be obvious which is the compressed image.

The same thing works in the audio example. Normal people's audio equipment is like your computer screen. Effectively there will be no difference between the two formats. But increase the resolution of the playback and if there is a difference it will become preceivable.

aeberbach, the study was supposed to determine whether there was a difference between CD audio and MP3 audio at 256kbps; the only way to do that is to use music where there exists the possibility of a difference. In compressed, badly recorded and mastered music, there may in fact be no noticable difference. But that's because the CD audio is bad to start with -- in otherwords, the MP3 is just as bad as the CDA in that case. It has nothing to do with whether or not a difference exists in music where it may. As I'm sure you know, the human ear /brain is much for attuned to differences in actual sound than in distortion. People probably can't generally hear the difference between CDA distortion and 64kbps MP3 distortion. Does that prove that 64kbps MP3 is just as good as CD audio?

And tubed equipment most certainly makes a difference. As strange as it sounds, audiophiles pay enormous amounts of money for euphonic sound, not real sound. The fact is that a tubed system is never as reference quality as an otherwise equivalent solid-state system because it always introduces coloration. As for the speaker setup -- well, something tells me that their set of $5000 speakers (and that's MSRP) doesn't even have as much detail (the most important aspect in comparing CDA and MP3) as some of my headphones. Sure, they may be 'better' overall for reproducing music, but that doesn't mean they have the resolution necessary to allow one to perceive the differences in the format.

If you really think all of the information MP3 does away with is inaudible, it's not surprising you feel the way you do. But even assuming it does, MP3 artifacts (extra and distorted information) assures that there are differences between CDA and even high-bitrate MP3.

kerely

 

[JaZZ]

kerely...

...good analogy with the screen resolution! Actually I can set (and I do) the zoom factor to 100%, so I see every single pixel and definitely the data reduction artifacts, if they're obvious enough. But let's be generous – your analogy is very appropriate, I think.

Quote:

The fact is that a tubed system is never as reference quality as an otherwise equivalent solid-state system because it always introduces coloration.

Well said. You just have to add that the same applies to solid state equipment. So I'm not so sure if a tube amp is definitely worse for critical, comparing listening. My EMP is as adequate as my SS amps.

 

[aeberbach]

There are MP3s and MP3s. MP3s you find online are more often than not pretty bad, and the whole MP3 format has a bad name because of the terabytes of crap that was spread in the days of Napster and continues to go around Kazaa, Gnutella, Carracho etc. The ones I've encoded are good. If they sound the same with my headphone setup that I mentioned they're certainly going to sound the same with my mid-price Paradigm speakers.

I still don't believe the source CD makes a difference. MP3s are supposed to be bad in two ways, first that they introduce artifacts such as ringing or haze and second that they boost or cut certain frequencies. Those kinds of problems should be discernable in any music. Pink noise should be a fair source for this test. What matters is that the MP3 is the same as the source and that means it should be exactly as bad. But this is just speculation on the part of NewportGeek, nobody has any idea of what music they used. Still we can assume that the chances of them picking 20 spectacularly bad recordings are slim.

This is exactly why "Cables, Power, Tweaks, Speakers, Accessories (DBT-Free Forum)" is DBT-free - too often DBT reveals no audible difference and then people get all offended when their highly-priced and cleverly marketed gear gets dissed. Don't take it personally. If anyone here can pick the MP3 from the CD every time, great. But everyone should try it for themselves and not just accept that MP3 is no good because "CD's sound better than MP3's. Period." - that's ********, same as if you said MP3s were always identical.

 

[JMS]

I have done some blind tests with 128kbps MP3's, using myself and 3 other subjects, that suggest MP3 encoding does not deserve nearly the bad reputation it gets on the internet.

First, let me point out some flaws in almost EVERYONE's evaluation of MP3's. No offense, but chances are YOUR evaluation is also flawed. I know this from having posted on other audio forums.

1. Getting MP3's from the iternet and evaluating against one's own CD. This is probably the way most people evaluate MP3's, and most MP3's I've gotten off Kazaa do sound like crap. The problems are obvious: you don't know the source (could be a 10-th generation dubbed tape), the CD reader (many had clicks/pops), the encoder used, etc. etc. I'd guess that 90% of MP3's reputation for bad sound quality are due to these factors.

2. Playing MP3's and CD's through different devices. Until the last few years when burners became widely used, it was extremely difficult for a consumer to play MP3's and CD's through the same source. CD's had to be played by a CD player, MP3's had to be played off the computer. If the CD was played on the computer, it probably went through different circuitry (e.g., straight off CD-ROM's DAC). Also there's the issue of level-matching, etc. etc.

3. Playing MP3's from the computer. I'd think many people's sound cards/computer fan noise introduce more audible distortion than the MP3 encoding process (accoiding to my findings about MP3 quality; see below).

4. Reading and burning CD's. CD readers make mistakes, unless you use EAC. CD burners make mistakes. Even the very best ones like Sony and Plextor. If you don't believe me, try burning a Redbook CD, reextract it, and then compare with an extraction of the original. I guarantee they'll be different. So different, in fact, you can see the differences visually by using a wave editor like CoolEdit. It is misleading to compare even a decoded MP3 burned onto CD with the original CD.

There are probably other flaws that I'm forgetting, but these are the major ones.

The fairest way to evaluate the MP3 encoding process that consumers can readily perform, in my opinion, would be to extract a CD into WAV, encode it using MP3, decode it again into WAV, and then burn BOTH the original WAV and the extracted/reextracted WAV onto CD. This minimizes distortions introduced by the CD reader/burner, differences in the playback device, etc. I have done exactly this using various tracks (mainly classical, but includes vocal and choral), encoded and decoded using MightyDAC's LAME MP3 codec at 128kbps, set for "best quality". I used the disc to conduct some brief blind listening tests on a proper stereo with 3 of my friends, who are not audio enthusiasts. I had tell them which was which without revealing the source. In summary, everyone concluded it was damn hard to tell the difference, as they all mainly guessed for their answers. I have listened to this disc extensively myself and agree with their findings, although I THINK I can tell a difference on a track or two now, but I would have to confirm it with more blind testing.

Now, I have played this disc on various speaker/headphone systems, including an Arcam Alpha 7SE -> META42/AD8620/2xEL2002 -> Sennheiser HD580 configuration. If we had so much trouble telling 128kbp's MP3's from the original, I wonder how everyone on the internet can tell a difference with 192kbps by playing through their computers in a noisy computer environment?

If you still don't believe me, there is an article published by an audio mag (I think Stereo Review) a few years ago that basically concluded similar results. I'll post when I dig up the URL in a bit.

 

[NewSc2]

Quote:

Originally posted by zowie I can understand one not having a preference, but if they sound exactly the same, or virtually so, then that means the playback equipment is not revealing enough. Two different mfg's $1000 CDP's sound noticeably different, although not necessarily better and worse, on a high end stereo. Eagle Driver makes a very good point. I'd add to that: 1. It's a big bother to convert a large CD collection to MP3. 2. You'd still probably want to store the CDs for the inserts or eventual trade in (big waste of value to keep the inserts and dump the original disc). 3. Playback in factroy car stereos. 4. Remote control.

For me, all these are what my computer does better than my system. I'd much rather have all my CD's stored on my computer rather than having to get up to change between CDs, and I have a TV-out from my computer to the TV and a Cordless Keyboard/Mouse to play Winamp while i'm on my couch looking at the TV.

I still do keep all my CD's, the reason how I came across this site was because I was in the middle of encoding all my CD's into mp3's (about 60-70 CD's, I finished in about half a day, it's easy with EAC and Lame) and wanted some more information. I've been burning all my CD's as 320CBR.

A few of you brought up a good point, mp3's burned onto CD's. I didn't really think of that, and I probably will consider it in the future. The reason I wanted to work with mp3's was that I'm probably going to get the Ety4S/SuperMini/iPod combo, and will do a considerable amount of listening out of that.