Here's a new test for the AAC+ codec used in HD Radio. People love to claim that they hear processing artifacts. HEY GOLDEN EARS, PROVE IT! ;)

If you really can tell such a huge degradation from aac+ coding on HD radio, PROVE IT! Tell me which two of these files are uncompressed cd rips, which one was compressed to aac+ at 96kbps, and which was compressed at 48kbps (uncompressed back to .wav so all files are of identical size). If you don't get all four then you've proven one thing...you're only guessing! Science...what a concept!

Coding was done with the MediaCoder program

01 http://www.theproductionroom.net/coal01.wav

02 http://www.theproductionroom.net/coal02.wav

03 http://www.theproductionroom.net/coal03.wav

04 http://www.theproductionroom.net/coal04.wav

Mike,
I can clearly tell the difference between 48k, 96k and un-compressed. (I've done plenty of A/B comparisons of compression my self).

After going through all the files a couple of times, and hearing absolutely NO difference, I did the ol' "listen to only the out of phase signal" trick, and ALL four were absolutely without question identical (they all have compression artifacts, I would assume 96k).

Just to confirm my suspicions, I took one of the derived matrix files I made, opened it up in Audacity, and panned it to the right. One by one, I imported a matrix decoded versions of the rest of the files, and panned them all the way to the left. The sound was exactly the same in both channels (mono).

Could you quick double check the files, Mike?

Here's a new test for the AAC+ codec used in HD Radio. People love to claim that they hear processing artifacts. HEY GOLDEN EARS, PROVE IT! ;)

If you really can tell such a huge degradation from aac+ coding on HD radio, PROVE IT! Tell me which two of these files are uncompressed cd rips, which one was compressed to aac+ at 96kbps, and which was compressed at 48kbps (uncompressed back to .wav so all files are of identical size). If you don't get all four then you've proven one thing...you're only guessing! Science...what a concept!

Coding was done with the MediaCoder program

01 http://www.theproductionroom.net/coal01.wav

02 http://www.theproductionroom.net/coal02.wav

03 http://www.theproductionroom.net/coal03.wav

04 http://www.theproductionroom.net/coal04.wav

I can't say that I know exaclty which is which, but I can tell you which I like! I think I like Coal 3 best. Coal 4 sounded ok as well, then 2, then 1.

Here's a new test for the AAC+ codec used in HD Radio. People love to claim that they hear processing artifacts. HEY GOLDEN EARS, PROVE IT! ;)

If you really can tell such a huge degradation from aac+ coding on HD radio, PROVE IT! Tell me which two of these files are uncompressed cd rips, which one was compressed to aac+ at 96kbps, and which was compressed at 48kbps (uncompressed back to .wav so all files are of identical size). If you don't get all four then you've proven one thing...you're only guessing! Science...what a concept!

Coding was done with the MediaCoder program

01 http://www.theproductionroom.net/coal01.wav

02 http://www.theproductionroom.net/coal02.wav

03 http://www.theproductionroom.net/coal03.wav

04 http://www.theproductionroom.net/coal04.wav

They all sound the same to me.
Richard

Ok...here's the truth. It was a hoax. My four files are IDENTICAL. But some of you heard "differences", and even stated preferences. Which is exactly what I suspected would happen, and why I conducted this "test"...to show that we tend to hear what we expect to hear, not what's actually there. Which is why I am such a strong advocate of double-blind testing, and believe that subjective testing of audio gear is mostly b.s.

I apologize for perpretrating this (white) lie, but hope you can appreciate my motives. And I especially apologize to Mattdp, who spotted this almost immediately, and yet I told him (in a private message) that he was wrong...knowing in my heart of hearts that given a little more time and a larger sample, people would start to hear "differences".

I hope I've made my point, and PROMISE never to post files with fake "differences" again. I hope you'll trust that any future tests I do (and past ones I've done) are legitimate. Again, please forgive me, and understand my reasons. PEACE ;)

Mattdp asked if all the files were 96k. Actually no. They were all uncompressed. But like most cds these days, the level is WAY too hot on this cd. Obviously clipped if you look at it in Adobe Audition. I think that is probably where the artifacts came from.

Somehow record companies got the idea that louder is better...and they'll sacrifice anything, especially sound quality to get it. Sad!

You guys might find this article on CDs and the LOUDNESS WARS interesting (it's a must read):
http://www.austin360.com/music/content/music/stories/xl/2006/09/28cover.html

The article skipped over the real beginning of the loudness wars in records: the EP. Back in the 80's lots of bands released extended dance versions of their songs on 45 RPM EPs. They would put two seven minute songs on each side and the bass and dynamic range on these versions were nothing like what you would hear on their regular 33 RPM LPs. We always played EPs at dances as much as we could because before CDs it was the highest quality sound we could get. They sounded nothing like what we heard on the radio and LPs.

It wasn't a matter of remixing. Back in 1979 Public Image Limited released a bunch of pounding songs in the UK called Metal Box (http://www.amazon.com/Metal-Box-Public-Image-Limited/dp/B000007UDQ) which was a round metal can of EPs (a really expensive import at the time). These songs had so much bass you felt like your brain was being sucked out of your skull through your ears. It wasn't pleasant listening with headphones but they were killer songs to play at dances. No one had heard anything like this before.

When PIL rereleased the exact same songs on the LP Second Edition in the US, they didn't have the nearly the sonic impact that Metal Box had. When Second Edition came out on CD, the songs were even more pounding than the Metal Box versions.

Now pretty much every pop song sounds like Metal Box!

Ever heard the 12" 45rpm version of "The Power of Love" by Huey Lewis? MY GAWD! That damn thing kicks ass! It's loud, AND clean, AND the bass pumps, AND it still manages to be "dynamic" sounding!

Knowing a thing or two about vinyl (owning a turntable and five records), I have to ask the obligatory question: How exactly did they make the recording sound sooo 'loud'? From my limited understanding of the vinyl recording process, the louder it gets, the wider your grooves are, and the less play time you have. [From what I've read, this was the reason records always had a fairly balanced sound, because putting loads of bass on was impractical]

I've got a copy of Chicago Transit Authority (listening to a rip of South California Purples right now), and they can barely pack three 7 minute songs onto one side of a 12 LP, so how did they pack two (really loud) 7 minute songs onto one side of a 7" 45, or are we talking 10" or something?

Did these super loud records push the limits on playback equipment?


BTW, Mike and Scowl - are you guys still into vinyl?

For me, my whole investment in a turnable was justified when I got the Chariots of Fire soundtrack. By far, that is the single best sounding recording I have on ANY medium (vinyl, CD or tape).

Also, was there a noticeable improvement from 12" 33s to 12" 45s?

I've got a copy of Chicago Transit Authority (listening to a rip of South California Purples right now), and they can barely pack three 7 minute songs onto one side of a 12 LP, so how did they pack two (really loud) 7 minute songs onto one side of a 7" 45, or are we talking 10" or something?
EPs are 12" 45 RPM records. Or they were. Well, I know some punk bands still release "EPs" but they're really just short standard CDs.

Did these super loud records push the limits on playback equipment?
No problems that I remember. We were using professional equipment.

BTW, Mike and Scowl - are you guys still into vinyl?
I'm not. I have hundreds of records sitting in my basement. There's a lot of stuff down there I wouldn't listen to any more (electronic, new age, and even worse stuff).

Also, was there a noticeable improvement from 12" 33s to 12" 45s?
Yeah, that what EPs were.

Last first...yes, 12" 45s CAN sound noticably better than 12" 33 1/3 records, and for the same reason that a 15ips reel to reel recording can sound better than one recorded at 7 1/2ips...more physical material passes by the stylus/recording head per second. There's more room for the waveform. Playing time is traded for quality.

Yes I still love vinyl, but admit that I'm too damn lazy to play it lots of times. I've transferred lots of my lps (and I have hundreds) to cds and mp3s, so I can take them anywhere. I don't believe they sound BETTER than cds, but I do believe they sound better than they have any right to...after all, you're dragging a rock through a plastic groove! That it reproduces anything resembling music is something of a miracle!

PEAK levels do as much to make grooves wide as average levels. Yet the ear perceives loudness by the AVERAGE level. Average levels can be boosted (at the expense of peaks) with compressors and limiters. It's the sudden, huge PEAKS that give the stylus fits. A limiter can simultaneously make a record sound louder, AND by clipping the peak, make it easier for the playback system to track.

12" 45s were often among the best sounding versions of recordings. Sometimes they sounded MUCH better than the cd version, because more care was given during the mastering phase. But sadly the popularity of these recordings peaked at about the same time lp playback went into steep decline. A sad irony. And another: the best turntables and phono cartridges, with breathtakingly good reproduction, came after the cd had come to dominate the market. LPs sound better than ever, and nobody but hard-core audiophiles knows, or cares! ;)

Just curious, is difference one notices between CD and Vinyl mostly vinyl's playback distortion, or is it because Vinyl actually produces more accurate high frequency content?

In my experience, on a CD, the cymbals and other really HF stuff sounds kind of 'grainy' (that's the best I can describe it), while the HF stuff on vinyl sounds more smooth and natural. I've also noticed more of an airiness on records, that I've never experienced with digital audio.

Is this all just distortion, or are there some [technical] advantages to Vinyl.

[Don't get me wrong, I think 192/24 (or someday, 384/32) would be vastly superior to ANY analog recording medium, but I'm a little skeptical about the quality of 44.1/16]

I can see this going into a debate on digital vs analog....in terms of a medium I like cd's/mp3s...tapes were OK but you had to keep magnets away from there and it didn't exactly go directly to a track (I know there were players of it that did though)

to note there is a few interesting things on records...supposedly there's a program that could scan a record and make a more accurate recording of it...and there's also a laser record player (no scratching at all) that costs serious $$$.I think most people went to the other forms of medium for the technology, not for the quality for the most part.

The problem with digital "grain" as you call it Mattdp is that when a master has too much treble content, you HEAR IT on cd. There is no attenuation of highs. Analog recording systems, including lp, are high frequency sponges. Treble is ALWAYS boosted during mastering to make up for losses down the line. This is why early cds were so piercingly bright...they were made from the same masters used for lp cutting (BAD MOVE).

What you're hearing as "grainy highs" is actually what the freakin' deaf (from years of thundrously loud monitoring) mastering engineers did to the recording. The vast majority of recordings for decades have had WAY too much treble content.