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Linux Based Stereo Components
davidu writes "MP3.com has a really cool interview with Joseph Mesterhazy, the creator of the LCDAT Linux-based MP3 player. If you haven't seen it, it is extremely cool. The interview also talks about how open standards make projects like this easier. This is is one of the first, not vapor, stereo quality, MP3 players out there, and it runs Linux!
" I wonder how many of us have duct taped perl scripts together
for our MP3 playing.
>I don't want a harddrive in my car.
>A CD/DVD drive is a safer and cheaper solution.
Don't hold your breath waiting for this to happen.
The designer of the empeg said that he had considered a cdrom drive during the design of the empeg. He ruled it out because car cd components don't have data capability (so they can't read CDROM) and CDROM components aren't engineered ruggedly enough for in car usage. The are rather flimsy designs suitable only for stable desktop use.
Only one nit: you've confused bits and bytes. mp3 records generally at 128k_bits_per second etc, and the CD is approx 1400 kbits/sec.
jealous? :P
I wonder how many of us have duct taped perl scripts together for our MP3 playing.
:) Maybe I'll release it one day...
Believe me your not the only silly person. I hacked together a "playlister program" in C++ with a bunch of shell scripts to send requests to it. It reads filenames from a playlist, fork and executes mpg123. When it gets a request it always plays that next...
Works great from WindowMaker menus
regards
Izak Burger (gpf@pikkedil.energie.sun.ac.za)
Linux sucks dead kittens through a garden hose
:)
That's pretty amazing won't you say? It also finishes infinite loops in sub 10 sec. btw
I purchased a Micronics M55hi+ motherboard from an online surplus store (www.centrix-intl.com -- I'm pretty sure they don't have them anymore) for $19 and it has a built-in Vibra16 chipset (same chips used in the genuine SoundBlaster 16 cards). It's an ATX board, and can hold any pentium (but not MMX without a special adapter). I paid $19 for the board.. And the sound output quality is great, very little noise. (My primary computer has a much newer mb with on-board SoundPro chipset, and the sound coming out of there is TERRIBLY noisy and generally sounds crappy. But from the Vibra chips, it approaches CD quality.)
So, see if you can find a Micronics M55hi+ board anywhere. I think it was originally manufactured for OEM machines (like Packard Bell) so it's not that great of a board, but it was dirt cheap and it has excellent sound quality.
Certainly a true statement. Of course, this reminds me of my theory about that "girls don't care about important things." When was the last time you heard a girl say, :)
"Sure, the iMac has nice colors, but this Dell has 256 MB of RAM!" or "I just brought my Conrad-Johnson amp home; I found the bass on the Krell to be too
muddy."?
For God's sake, should you ever find a supply of these women, let me know!!! :)
Also, fwiw, I think that there are quite a number of audiophiles who might beinterested in this kind of equipment for convienience sake; notably, audiophiles that tend to leave music playing in the backgroud when they're not doing some serious listening. Of course, when the urge to really *listen* to some music comes, off go the digitally compressed tunes, and out comes the vinyl, or HDCD, or 30IPS tape, or what have you.
BTW, I would guess that much of the degridation you see in sound qualities for MP3s is due to loss of timing information. This is why it's quite easy to tell the difference between CD and analog on a good system. I wonder if anyone has taken any measurements.
Now if only they'd gone with the Sony system instead of AC3 for DVDs... maybe we would have found out how good music that's been lossily compressed could sound :/
Certainly a true statement. Of course, this reminds me of my theory about that "girls don't care about important things." When was the last time you heard a girl say, "Sure, the iMac has nice colors, but this Dell has 256 MB of RAM!" or "I just brought my Conrad-Johnson amp home; I found the bass on the Krell to be too muddy."? :)
For God's sake, should you ever find a supply of these women, let me know!!! :)
Also, fwiw, I think that there are quite a number of audiophiles who might beinterested in this kind of equipment for convienience sake; notably, audiophiles that tend to leave music playing in the backgroud when they're not doing some serious listening. Of course, when the urge to really *listen* to some music comes, off go the digitally compressed tunes, and out comes the vinyl, or HDCD, or 30IPS tape, or what have you.
BTW, I would guess that much of the degridation you see in sound qualities for MP3s is due to loss of timing information. This is why it's quite easy to tell the difference between CD and analog on a good system. I wonder if anyone has taken any measurements.
Now if only they'd gone with the Sony system instead of AC3 for DVDs... maybe we would have found out how good music that's been lossily compressed could sound :/
Certainly a true statement. Of course, this reminds me of my theory about that "girls don't care about important things." When was the last time you heard a girl say, "Sure, the iMac has nice colors, but this Dell has 256 MB of RAM!" or "I just brought my Conrad-Johnson amp home; I found the bass on the Krell to be too muddy."? :)
For God's sake, should you ever find a supply of these women, let me know!!! :)
Also, fwiw, I think that there are quite a number of audiophiles who might be interested in this kind of equipment for convenience sake; notably, audiophiles that tend to leave music playing in the background when they're not doing some serious listening. Of course, when the urge to really *listen* to some music comes, off go the digitally compressed tunes, and out comes the vinyl, or HDCD, or 30IPS tape, or what have you.
BTW, I would guess that much of the degradation you see in sound qualities for MP3s is due to loss of timing information. This is why it's quite easy to tell the difference between CD and analog on a good system. I wonder if anyone has taken any measurements.
Now if only they'd gone with the Sony system instead of AC3 for DVDs... maybe we would have found out how good music that's been lossily compressed could sound :/
Just wondering if any of you know or have
some useful audio mpeg decoding source codes
for ol DOS (I have watcom c/c++ 10).
Its for a project were doing for a local
disco place.
Hopefully this can come of some use to people who know little about mp3s and CDs. I forget the exact number, but audio on CDs takes up somewhere around 1400 kilobytes per second. The majority of mp3s don't even reach 256 kilobytes per second. The reason that mp3s can sound so close to CD audio with the savings in size is through the masking of frequencies.
The phenomenon is almost equivilant to the difference between newsprint advertisements and a painting (not in quality, but in terms of perception). With the newsprint, the picture is actually made up of tiny dots which, when viewed from afar, blend together to make a seamless looking picture, even though there are gaps if you look up close. Mp3s use the same principle, only with sound. Say you have a sound with a frequency of 80hertz at 60decibels; because of how our hearing works, that sound being played will mask out sounds around it. So for instance, if you had that sound playing, and suddenly you played a frequency of 75hertz at 30decibels, there would be no audible difference (note: these are numbers I'm making up to illustrate the general idea. I don't know the actual mathematics of it).
What mp3s do is allocate a certain amount of space (128kilobytes/sec or 256kilobytes/sec), break down a second of music into a number of frames (usually 44.1) and then for each frame looks at what the frequencies are, and gradually and more agressively gets rid of the sound that is most likely to next be masked.
The problem that can arise with this fixed bitrate encoding is that the encoder is not making an overall judgement based on what the quality of each frame should be, it merely knows how much it MUST cut out of each second of music. The solution to this is VBR or variable bitrate encoding, which has not been very widely accepted as far as I've seen. The difference with this style of ecoding is that you specify to the encoding program a quality level to set the song, and then it will go through each frame and cut only enough sound to fit your preference for sound quality, not some arbitrary number.
Anyhow, I think that's enough of me rambling. Hopefully someone found that at least slightly informative and interesting.
Paelon
anyone have any experience with selecting a MB for this project? what is a good cheap combo?
You should try a soundcard with S/PDIF output...and connect it either to a digital capability preamp/amp directly or just rig up a DAC next to your analog amp. And these soundcards are pretty cheap these days (ex. SBLive! value, and it even works in Linux). No more interference from those 50Hz/60Hz power supplies, transformers, etc...
Of course you have to be a little "crazy" (like me, I guess =)) to even try this.
He probably just listens to them through a decent amplifier/speaker system.
mp3s are good, but no where near CD quality (and CD quality is pretty bad.)
Can anyone recommend a digital-out only soundcard?
Living in a small house allows me to connect the PC to the stereo, but the sound quality is rather poor.
I was going to buy a seperate DAC, but I can only justify the expense if I can find a sound card that outputs digitally (either coax or optical)
Excuse the PC/soundcard ignorance, but living on Planet Linux for the past couple of years means that I don't really know what's available nowadays.
----- Documentation is worth it just to be able to answer all your mail with 'RTFM' - Alan Cox.
It's not exactly perl, but it is rigging...
My web server machine has the disk space for tons of MP3s, but not enough CPU. The other machine (with plenty of CPU) lacks the disk to hold all of those things. So, I stream them HTTP-style from Apache into mpg123 all day long.
The first hack was making m3us and having Netscape pass them unmolested to mpg123. Then I rigged up a network-friendly thing to call netscape's "-remote loadURL" thing... finally I had something call THAT with a random mp3 URL... so you run that script and it starts playing one of many files over the network, assuming NS is running already.
The encore? I rigged my X-10 stuff (not a firecracker, something two way) to call the randomizer script and now any X-10 remote around my place can start it up. Very nice.
All Linux powered, and all "tools for the job" that interconnect. Life is good.
I totally agree, I listen to MP3s rarely, because the quality is so apparent. Especially on my very pricy audiophile system. On a cheap bookshelf system it's not a big deal, but on high-quality components its VERY noticable. Before you all start telling this guy that he's a loser and no one can possibly hear it, try it yourself. Here is a simple test that shouldn't take too long. Take any CD with a song that has lots of detail, preferablly something you know well. Just about anything thats not thrash metal or should work well. Take a song of the CD, MP3 it (try a couple different bitrates, the standard 128 is a lot worse then 256), and record it to a blank CDR. Now go to a stereo store that sells nice stuff. The nicer the equipment, the more revealing of the source limitations it is. Play both the original CD, and the MP3 on CD. Tell me which one sounds better.
:-( I think the reason why is mostly due to the licensing agreements (Yamaha owns the tech, but its free). Maybe someone can look into that more. Hopefully MP4, which uses a conglomeration of AAC (another better format) and VQF will improve the quality of MP3s.
There are other formats out there that are MUCH better vqf is one of my favorites, too bad there is no linux player
Spyky
Yeah. The question is, will your personal preference shift when you buy a better sound system? Mine did.
- Rainy
I'm putting this in the main thread 'cause the MD article I read (posted by Foxman98) was buried a level.
:). Even the $4000 stereo I put in my car didn't sound as good as a properly set-up soud stage in a home room. There's something about a larger room that just gives more ambiance.
I used to work at a high-end stereo shop, and we sold everything from Sony cheapo stuff to Sony ES to Denon and up. I got the chance to play around with an MD versus a CD. After some rigging, I was able to switch to and from the MD and CD, and I had the exact same music playing simultaneously. On cheaper speakers ($300/pr) it wasn't real easy to tell the difference, however on more expensive speakers ($1800/pr) the difference was night and day. Compared to the CD, the MD was a little shrill, and the base was a little "boomier". All in all, the MD would probably sound better in a car than a CD, simply because a car stereo usually doesn't reproduce quality highs and lows (mids are good tho
Anywaze, on to MP3. From what I read about the compression technologies, it seems like the MD and MP3 algorithims are similar, but MP3 is designed to run at 128K/s to 256K/s data streams, where MD's are about 512K/s. (Correct me if I'm wrong, it's been a few years) I'd bet that an MD compared to an MP3 in a car would sound identical, but on a quality home system the difference would be night and day. Now say we got a better MP3 player (XAudio extensions anyone?) that supported a mic-feedback EQ so the system could be tuned, it'd probably sound damn good -- especially for the price!
Just my $.02.
LOAD "SIG",8,1
LOADING...
READY.
RUN
It might be overkill, but the TB Fiji has an optional S/PDIF daughtercard, and is supported under Linux. (I've verified that both digital in and digital out work) I'm not entirely sure this is needed, though, as the analog out from the Fiji is _very_ good as it is. Better than any of the portable CD players I have, and probably comparable to a $4-500 player. These might be a bit tough to find now, but well worth the effort, IMHO.
Actually I had this problem with my (Very high end) gear as well... I found though that either running a digital output or at least common grounding the equpiment made a HUGE improvement.. just running a wire from the metal on the back of your computer to the case of the NAD might be enough to significantly reduce the noise. For some reason the computer seems to run on a floating ground, while the stereo equipment is at third prong ground.
For an interesting read, visit the Dolby site and their comparison of MPEG and AC-3 (the Dolby Digital standard). Both support encoding at different bit rates and it is recognized that 192kb/s provides "good" stereo quality.
Most Dolby tracks are encoded at 384kb/s and in their tests MPEG at 320kb/s was "inferior". Still, 384 kb/s is a manageable bit rate given todays storage.
Free AC-3 anyone?
Hmm, lemme see... my cheap speakers/stereo
B&O audio components....
Bose 901's, 601's and 301's ($1600,$800,$500 repectively)
CD's and Mp3's sound the same on the normal enjoyment level...
Now, If I sit down and listen closely, being extremely picky and anal... I can hear the swiching and bit artifacts..
Final conclusion... dont use mp-3 if you are anal-retentive... the type that can tell that a record was played once already or that a current diamond cartridge has been used more than 10 times, use bi-wire to the speakers that is 50 conductor ribbon 00 gague to enhance the sound.
If you cant tell the difference between lamp cord or $100.00 a foot audio speaker cable (99.9% of all humans) then mp-3's will sound perfect to you
There is one thing on this planet I cannot stand... an audiophile...
Do not look at laser with remaining good eye.
The site says that it is not a commercial product, but rather a build-one-yourself-from-these-specs type of thing.
It seems to me that for a product to be vapor it has to be commercial and not shipping. As Joe's office-mate I can assure you that the player is quite solid, nothing gaseous about it.
The unencoded ripped wav should be identical to the CD quality, although playing it through your computer might (read: definitely will) give lower quality output than if you played it through your stereo system. Once the wav is encoded a lot of information is tossed out, and that is what causes the biggest quality loss. Another thing to watch out for is that all bitrates are not created equal. It's almost as important what program is used to encode an mp3 as it is what bitrate is allocated to it, because some encoders use dirty encoding tricks (cutting off any frequencies over 16khz, etc.)
Paelon
I don't want a harddrive in my car.
A CD/DVD drive is a safer and cheaper solution.
As far as home audio device, I would buy one
of the following:
1. Some device that rom boots linux has remote
and plays mp3s off of CD/DVD's. I would pay $250.
2. A black computer case that is the size of
a home audio device and maybe has has LCD built
in. I can put all the stuff in my self, but
I would rather it be meant for a computer so
I dont have to get out the drill and hack saw.
I would pay $70 or $100 if it has LCD and IR
built in.
With (2) I could just build something that plays mp3Cds right now, and upgrade the software later to play DVD's and more.
They haven't yet realized that audio hardware is as dead as physical audio media.
The only Hi-fi equipment that will exist 10 years from now are amps, speakers, and headphones.
-bonkydog
Quid rides? Mutato nomine de te fabula narratur. -Horace, Satirae
In short, for me [the audio quality issue] isn't one.
But for many it is. Sure, some people moved from cassette to CD because there's no rewinding, etc. But sound quality is the real selling point. (Yes, I'm aware that many audiophiles use their turntables instead of their digital equipment quite frequently).
In the interview I stated I built this machine to replace my *analog* equipment. I don't think anyone can argue that a 256kb/s MP3 (on a digital output) sounds worse than a cassette tape. Perhaps if you bought a $1000 tape deck, but if this is the case I am sure you could care less about MP3.
Good point, but I feel that such a device is mostly competing for market share against CD-Rs and the like. But I'd still say a good turntable will sound better than a 256 kbps MP3. Of course, to whom it will sound better is a very (!) small minority... and like you said, those folks could care less about MP3.
Yes, if you listen for it, you can hear the compression of the audio. Especially in the rear channels if you place your receiver in a surround mode
Why anybody would put an audio track designed for 2-channel listening into surround mode is beyond me. In two channel mode, can put you "there," where the sound doesn't appear to be coming from a couple of speakers. When fed into more than 2 channels, all imaging and soundstage qualities disappear. Of course, (reversing what you said above), the people who care about MP3 don't care.
As far as I am concerned it sounds *close* enough to a CD, that I don't mind if there is a little swishy-ness in the cymbals. The advantages of having all my music at at the touch of a button far outweigh this.
For me, the convenience advantages don't outweigh the sonic disadvantages. But then again, I place more emphasis on how my amp sounds than how many watts I can claim it's rated at. (Dude, my new Sony pumps out 200x5!) It's also the reason I have a single-disc CD player rather than a two million disc changer - better sound quality.
It is all a matter of personal preference
Certainly a true statement. Of course, this reminds me of my theory about that "girls don't care about important things." When was the last time you heard a girl say, "Sure, the iMac has nice colors, but this Dell has 256 MB of RAM!" or "I just brought my Conrad-Johnson amp home; I found the bass on the Krell to be too muddy."?
Please excuse my generalizations, I mean it only in jest. And Joe, if you want to send me an LCDAT and prove me wrong about sound quality, please do.
-Drew Boyles-
dboyles@resnet.gatech.edu
-- "Complacency is a far more dangerous attitude than outrage." -Naomi Littlebear
I'm waiting for a mobile (mountable in an automobile) version of one of these things that can work with CD-ROMS with MP3s on them, play traditional or standard audio CDs, and also includes a radio tuner. This should be technically possible, right?
Using a serial connection to (slowly) upload a set of songs is not for me...
I wonder how many of us have duct taped perl scripts together for our MP3 playing.
Guilty as charged. I spend most of my time in the X Window System, but running xTerms (or their equivalent). It's much easier to control my MP3 listening from a cobbled together Perl script than to switch to the mouse and manipulate a GUI player, then switch back to a keyboard and resume work...
I thought I was the only person silly enough to do this...
"Flame away, I wear asbestos underwear"
Joseph is a member of mp3stereo@lists.gofast.net. If you're at all interested in issues about building your own stereo components, then you need to join the list. Send a message to mp3stereo-help@lists.gofast.net to learn how to sign up.
Lucky for me, the emancipation proclamation came through just in time...*whew*
is that ever since I got sensitive speakers/ amp (paradigm monitor 3's/ NAD) I can't really enjoy mp3s anymore. Even at 256kbps, I can hear some noises. I think 256 is actually good enough but changes of voltage in computer, interference from peripherals, etc, make it fall *way* short of quality I get from any $200-300 cd player. As I said, the difference is so big I can't really enjoy mp3s anymore. So, does this thing take care of that or not?
- Rainy
You want something way cool that is NOT vapor? The empeg car.
This thing makes me salivate. A removable in-dash MP3 player. Connect it to your PC to download music, create playlists, etc. Put it back in your car and use the remote to select your song/playlist. Store 476 hours of music on it (that's three weeks straight without a repeat). It has an awesome LED GUI including real-time visuals. And, it runs Linux. If you know a little Python, you can create your own custom GUI for it!
bp
This article seems to imply the empeg unit doesn't exist. Strange that mine is shipping as I speak.
/dev/null'ed.
I submitted an article last week about how they're shipping unit now, but it was
The empeg car player is *not* vapourware.
The only time I've noticed quality issues over regular CD tracks is when screwing with the encoder's settings, or with a very dynamic audio source (loud, quiet, loud...)
I've gotten around the latter problem by encoding everything VBR. I achieve a *miniumum* level of 128kbps, but when there is a quiet part to the music I've seen it hit ~376kbps if I'm not mistaken to keep the quality up.
I use LAME, BTW. It seems to me that the encoder is the problem if you're hearing artifacts of encoding.
I won't step out and say there is no difference, but with what I listen to and with what I listen to them through I haven't found anything that would make me want to cringe. At the *very* worst, it sounds like listening to a perfectly tuned FM stereo radio. At best, I can't tell the difference from the CD I cut it from.
There are a few things you can do to improve mp3 playback. The site said it used a SPDIF connector on the sound card / motherboard with a TOSLINK adaptor to a reciever. If you use the analog link, you're more likely to get noise as analog electronics and DACS in sound cards are pretty cheap.
Another is to max the bitrate. I thought 512k rates were possible, but I never tried. There are also better encoders available. I'd say which ones, but I really don't remember. Some encoders do better than others.
But if you already believe that CDs are crap, then you're screwed, as entropy dictates any transfer will only be as good as the source, no better, and likely worse, and I guess there are enough people that believe MP3s are crap at any rate, so I can't help on that.
-Drew Boyles-
dboyles@resnet.gatech.edu
-- "Complacency is a far more dangerous attitude than outrage." -Naomi Littlebear
Hi, I am the author of this project, and would like to share my opinion about this whole MP3 audio-quality issue that a lot of people have brought up:
In short, for me it isn't one.
In the interview I stated I built this machine to replace my *analog* equipment. I don't think anyone can argue that a 256kb/s MP3 (on a digital output) sounds worse than a cassette tape. Perhaps if you bought a $1000 tape deck, but if this is the case I am sure you could care less about MP3.
Yes, if you listen for it, you can hear the compression of the audio. Especially in the rear channels if you place your receiver in a surround mode. If this distracts you to the point you cannot listen to the audio, fine. Don't use MP3. I encoded most of my MP3 at 160kb/s, and my classical music and ambient music at 256kb/s. As far as I am concerned it sounds *close* enough to a CD, that I don't mind if there is a little swishy-ness in the cymbals. The advantages of having all my music at at the touch of a button far outweigh this.
How many people do you know record TV shows at SLP speed on their VCR? Probably a lot. For them the advantage of being able to record 6 hours of video on a 2 hour (SP) tape makes up for the loss in video/audio quality.
It is all a matter of personal preference.
Hmm, I guess I qualify as one of those duct-tape people. ;).
I've got a cgi script (in perl of course), running on Apache, that gives me a nice listing of my songs and lets me pick the ones I want. Also it plays random songs and a kind of "radio"-streaming (it just streams random songs after each other. Currently I'm thinking of implementing song-titles via festival. All the hooks are there, I just need some time to implement it
Anyways, these things are really neat, I especially like those empeg car players.... now if I just had a car ;). -- sdt
One thing that makes direct bitrate comparison difficult is that the MD recorder must of course be a real-time encoder implemented on a relatively modest DSP, whereas MP3 can take arbitrary amounts of time (and memory). As with any compression scheme (music, files, video etc), the more time you have and the more signal you can look at, the better job you can do. I've never done a direct MD vs MP3 comparison, but it wouldn't surprise me at all if 256k MP3 was comparable if not better.