192k vs. 128k:

Was 192 as high as you went with the tests?

It might be fun to take one or two pieces which exhibited the worst aliasing (to your ear) and try them at higher bitrates, or at highest-quality VBR rates using LAME or Xing.

When I encode in high-quality VBR, I've seen some frames jump to 320kbps...

Biggest difference in the bass is that it looses its firmness and less defined;

I'm starting to hear more and more people say this. It sounds illogical to me (the low frequencies should be reproduced quite well at any bit rate), but these comments are starting to reach a critical mass. I haven't ever noticed any problems with the bass, but now I'll start listening more closely.

In some cases, you can attribute those comments to the fact that many people are previewing the MP3s on different sound reproduction equipment than the CDs they're comparing them to. But in your case you did the Right Thing and tested the encoder only by decoding the MP3 back down to a wav file and burning that to a CD. So it's not an equipment thing in your case.

Same applies, but in higher order; particularly narrowing of soundstage was noticeable. Stuff that was firmly located to the left made a shift inwards.

Important information for the "soundstage" discussion we were having a while ago. Of course, this is the MP3-soundstage-limitation question, not the Empeg-soundstage-limitation question.

Also, when listening in the car imaging and soundstaging in the audiophile sense become pretty moot anyway.

Don't let Doug hear you say that! Many of us car audio enthusiasts have better sound systems in our cars than in our homes.

It effects of datareduction appear to wreak the greatest havoc with the classical piece, least with the fairly uncomplicated track with woman's voice.

Interesting. I've noticed that solo voice can really show up artifacting. Just yesterday I was noticing some compression artifacts on a solo female voice track (The album happened to be "Mouth Music" by Swan and Mackenzie). I didn't think the track was complex enough to cause audible artifacting, the voice was firmly in the midrange and very clean. But what it showed was that having all the "air" around the voice allowed faint artifacts to become audible, especially on note decays, that would otherwise have been buried in the rest of the mixed instruments.

And this was egregious artifacting, too. It wasn't subtle. You know that gurgly, alien-talking-underwater kind of sound you hear on really-heavily-compressed streaming RealAudio tracks? I could hear that as her voice trailed off on certain notes. And this is at 128k, not at lower bitrates where you would expect to hear it.

Mind you, I had to be listening at full volume to hear it. And I was running the voladj kernel, so it was cranking up the note decays well above the noise floor, so it's kind of unfair, I guess. Still, it was there.

___________
Tony Fabris

Hi!

I'm in Anchorage as well. I also have the only Mark I that is in Alaska.

Reg_2845 Serial #00173

Also, when listening in the car imaging and soundstaging in the audiophile sense become pretty moot anyway.

Don't let Doug hear you say that! Many of us car audio enthusiasts have better sound systems in our cars than in our homes.

But you've gotta admit, in most people's cases this is true. The soundstage isn't too bad for the driver in relation to the rear speakers in most cars, but with speakers in the door panels it's way off. If you've got kick panels it's alot better because you'll move the stage forward a bit, but there's no way around the fact that--in most vehicles--the placement of the speakers is not ideal (unless you happen to own a car where the driver's seat is in the middle)


DiGNAN

...but with speakers in the door panels it's way off.

Not necessarily.

Being basically selfish (and since most of my passengers could care less about staging and imaging) I shift the left-right balance one notch towards the passenger side -- i.e, the right side of the car gets a little more volume than the left side. This has the effect of exactly centering the image for the driver, at the expense of the passenger -- but it is a small change, and unless the passenger heard it both ways, he would never know.

In competition judging, one of the tracks is a series of seven snare drum beats that travel left to right across the sound stage. Ideally, they would be positioned for both driver and passenger like this:

x........x........x........x........x........x........x

And there are some cars that compete that do, indeed, achieve this, albeit expensively.

Most cars come out like this:

x....x....x....x.................x....x....x....... for the driver and the mirror image for the passenger.

According to the judging sheets, my car comes out more like this:

..x......x......x..........x..........x....x....x..... for the driver, and
........x....x....x........x........x......x......x.. for the passenger.

In other words, the stage is a bit narrower than optimal, and the separation gets compressed on the left and right sides, and compressed a little more on the side opposite the listener. (When in championship judging mode with two judges, one in each front seat, I don't shift the left-right balance, but leave it centered.) Because of the acoustics of my car (a fairly large station wagon) my staging and imaging is better than most, due more to blind luck than any cleverness on my part.

Finally, my car is quieter than most -- no audible engine noise, lots of sound deadening, aerodynamically shaped enough that wind noise is pretty minimal, so even at highway speeds I keep most subtle nuances of the music. rjlov's "normalizer" program will make it even better, but I have to actually have an empeg first, I guess... :-(

I guess the above rambling discourse is all just to say that a car can be a better listening environment than most people give credit, if you have the proper car and the proper equipment and tuning. I think the fact that the car is such a controlled environment helps: you don't have to deal with asymmetrical rooms or rooms with some walls close by and other walls effectively not there at all as in an open living room environment.

tanstaafl.


"There Ain't No Such Thing As A Free Lunch"

Being basically selfish (and since most of my passengers could care less about staging and imaging) I shift the left-right balance one notch towards the passenger side -- i.e, the right side of the car gets a little more volume than the left side

So I was right. I knew you could do that, and I would but I typically do have picky passengers .

DiGNAN

Was 192 as high as you went with the tests?

Yes, I wanted to stay close to 128k to see how much "damage" "internet-standard" would do.

It might be fun to take one or two pieces which exhibited the worst aliasing (to your ear) and try them at higher bitrates, or at highest-quality VBR rates using LAME or Xing.

When I have a bit of time (!) that's part of the next experiment. I'm also very curious to see what the Xing, Blade, Lame, etc. encoders sound like in various modes compared to an original WAV. Don't hold your breath for the results though...

Any other suggestions to add to the experiment?

Cas

Bruno writes: Buy 2 or more cheaper disks and RAID them using software-RAID.

I hadn't seriously considered this before, but it's an interesting idea. I don't really care about speed, per se. The sole purpose of this huge disk (or disk group) is to hold MP3s.

As far as price goes, let's check again at CDW:

- IBM 75GB 7200rpm: $589 ($7.85/GB)
- IBM 60GB 7200rpm: $480 ($8.00/GB)
- IBM 45GB 7200rpm: $299 ($6.64/GB)
- IBM 30GB 7200rpm: $209 ($6.97/GB)

- Maxtor 60GB 5400rpm: $300 ($5.00/GB)
- Maxtor 40GB 7200rpm: $265 ($6.63/GB)
- Maxtor 30GB 5400rpm: $145 ($4.83/GB)

- Western Digital 45GB 5400rpm: $199 ($4.42/GB)

So, at 7200rpm, the best deal seems to be a tie between IBM and Maxtor. If you're trying to trade off speed for space, the Western Digital disks have the best price/storage ratio.

By the way, what backup are you going to use for 75Gb?

Backups? I've still got a huge bookcase full of the original CDs. I don't really care so much about my home machine. Anything that really matters is at work on the NetApp box (RAID with all the bells and whistles). Besides, the EMPEG (once I can buy large-enough laptop hard drives) will be the real backup.

($4.42/GB)

I once spent (actually, the company I worked for spent...) $1200 for an 80 MB hard drive. That works out to be about $15,000/GB, that was in the mid 1980's.

In the 1970's, another company I worked for used DataPoint mini-computers whose 5 MB hard drives (the size of a small filing cabinet) cost over $8,000. That's $1,600,000/GB.

And you want me to comparison shop so I can save something like 40 cents per gigabyte.... Ri i i g h t....



tanstaafl.



"There Ain't No Such Thing As A Free Lunch"

Good prices! Still, I intend to wait until the EMPEG is in danger of arriving. Then I start spending inordinate amounts of time feeding CDs to the machine. By then, prices will only be cheaper.

Although i`ve never performed a real blind test, i`ve done test like this before and noticed the same things.
I made mp3`s, and burnt them in wav format, then played em in car.

128kbps gives u bass which is "different" I cant explain why exactly, it seems exagerrated and boomy compared to the orginal. (my mates get in and marvel at how much bassier it is if i have 128k mp3`s playin, i dont like it, it sounds fake)
The top end becomes swirrly and swishy, imaging is poor (excuse the techy terms :))

192kbps is good, bass is pretty accurate and top end swishyness goes, something is different about the sound, but unless listening back to back with a wav i couldnt noitce it. Imaging is nearly perfect

HQ Lame VBR (about 180-230kbps) awesome, high end is perfect, bass stays unchanged. Soundstage perhaps "lifts" slightly, imaging is spot on, imo this is what eveyone should use, its almost perfect.

256kbps, Huge files, perfect sound, same soundstage points as above.

I used either lame or Opticom Mp3 Producer 2.1 (ffraunhofer (sp?))

its the classic quality v filesize thing, i would always use 160k or more, and i`d never ever even if i had no other enocder, use xing :)
Xing gave me swisshy sounds and big bass at any bitrate, cant stand it.

What settings and what version of lame are you using?

Sean