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Do it yourself MP3 Stereo 85

ckotso writes "There's this guy who has created a hi-fi-like MP3 player using an old PC case, an LCD screen+a few keys attached to the case, a P100 and a small HD booting linux. MP3s are read from a cd-rom, which means 12 hours of continous music at home. I guess it still needs work, but it seems quite good already. Now I know what to do with that old spare midi tower."
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Do it yourself MP3 Stereo

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  • by Anonymous Coward
    Conect the VGA to a VGA-NTSC converter, or us a video card with NTSC / S-Video out and connect it to your TV? That's whatI did, and I got one of those RF keyboard/mouse combo's to go with it. No solderin required. Play MP3's and surf.

  • by Anonymous Coward on Wednesday April 21, 1999 @10:45PM (#1922379)
    *please send all flames to /dev/null. This device references M$, viewer discretion is advised*

    How about grabbing a DOS based MP3 player, load MSCDEX in the autoexec, write a small program (started by the autoexec) to run your interface (input is from stdin remember? send data to LPT1 for the display. Cinch) and parse the CD to see if it is MP3 or *gasp* CDDA, or even MOD,S3M,it, etc. (if your into old school tunes) and go from there? We could squeeze the whole thing into a 1 meg boot EEPROM, with less boot time, and maybe just a little less memory needed? Linux kicks tail, but DOS could have a bit better use in small non-multitasking appliances like this one.

  • A similar project [thekeep.org], posted in a Slashdot discussion a while back. It has some interesting notes about running Linux in RAM only, so it can be shut down like any other stereo component.
  • hey,

    if you compile mpg123 w/ the 3DNow! optimizations you only get about 4~7% cpu utilization.

    i wonder if x11amp has the same optimization stuff in it.

  • Posted by Someone@Somewhere.earth:

    Have you checked www.empeg.com ?
    Their working on it....

  • Looks like a really nice concept (the player). And I applaude his efforts,I may build something similar one day. I have enough old 'puters lying about the place.

    See subject for webpage comment. I suspect I am not the only one w/o a 30" monitor. ;=

  • by pb ( 1020 )
    I've got an old P133 that would be more than enough hardware to make something like this. However, I'm sure that if I tried to do it myself I'd destroy it. Also, I wouldn't want to spend the money for better speakers, let alone an LCD display.

    Nah, might as well just play mp3's in the background on my K6/300. Gotta hate losing that 10% of CPU or whatever, darn.

    Now if only I had a CD-burner...
  • by pb ( 1020 )
    What were you using to play it? I know that a friend of mine had pretty good luck with a 486/133. :)

    Personally, I'd use mpg123, as optimized as possible, and start out playing mp3's downsampled to 22Khz, mono. If that works, start changing command-line parameters, and see what it supports.

    (However, it sounds like that computer might be a good candidate for that hardware decoder board for .mp3's that was just on slashdot... :)
  • Nope, I can't, my machine really is a K6/300, not a K6-2/300. :)

    (I bought it just before the K6-2's came out. But that's okay, if I wanted a new chip, I'd want, say, an overclocked Celeron, a K6-3 or a K7, or something nifty. But I don't. My K6/300 is more than enough horsepower for me right now, except for testing VMWare. But then, I don't really have much use for Windows, so that doesn't count. :)
  • by pb ( 1020 )
    I don't know how accurate their CPU usage reporting is... I've used more CPU under NT by moving the mouse. (try it, it's fun! :)
  • by Rendus ( 2430 )
    I have a 486DX2/50 in my bedroom playing mp3s for me. Running the precompiled binary of mpg123, with the flags -z2m. It plays 128kbps fine but I have the bitrate at 64kbps (my ears aren't exactly sensitive)...

    On an unrelated note, anyone know what would make klogd become a runaway process? I have to kill it because it keeps my load average at 1.00...
  • Last I heard, desktop computer CD-ROM drives were not designed to handle the vibrations experienced in a moving vehicle. It'd be interesting to know how well the one on this device works in motion, and how long it lasts.
  • I agree with you. The idea of a hi-fi component which takes a minute to boot (and several if it hasn't been shut down properly) seems rather inelegant and cumbersome; the fact that you can have it hosting log-ins and cracking RSA in the background doesn't quite make up for that.

    A DOS-alike could be useful; Isn't DR-DOS semi-freely available? Also, there may be a free implementation of DOS out there. Or possibly, if one was to go commercial, one could licence a RTOS, like OS/9 or QNX.

    Alternately, it may be possible to cut Linux down into a lighter OS. Possibly a Linux kernel minus unneeded drivers, modified to boot from the Flash BIOS space of a motherboard, and leaving out all but necessary processes. If you eliminate read-write filesystems, you can bypass the fsck problem as well.
  • I think most DAT drives can't do this. Some company sells a special DAT drive which can suck audio off DATs as well as reading/writing data; it comes with Macintosh software and is marketed at audio professionals.

    Of course, I could be wrong.

    As for ADAT, isn't that an entirely different format, storing multitrack audio on expensive VHS tapes?
  • But still it wouldn't power up instantly. Linux would still take maybe 10 seconds to boot.

    Then again, even with DOS there's the BIOS self-test time, which is unacceptable for a shelf hi-fi component. For such a device to be anything other than a geek curio, you'd have to replace the BIOS, possibly ROMming Linux or some similar OS.
  • There was a discussion yesterday on the autoLinux [bangsplat.org] mailing list about in-home MP3 players.

    One of the things we discussed on there was building lower-cost ($200-$300) units using embedded biscuit PC's with slow 486 processors and external decoders (for sound quality), and essentially sticking the linux kernel configured to boot via NFS into the flash.

    No harddrive, and keep the MP3's and software on the network. A lot of us have pretty big networks at home, seems a good way to keep all the MP3's together, and use them from multiple locations.

    You could also fit it in a much smaller case. One of the people on the list mentioned those PC-on-a-SIMM devices as a possible host.
  • I'll probably make the .prc (as well as the Perl script that it interfaces too on the Linux side) available once it actually does something more useful than what it does now, but unfortunately my time is split between quite a few things lately so it's not progressing as fast as I would have hoped.

    To answer the other reply here, this is not a plugin to Winamp, though I suppose such a thing would be possible (I've experimented a little with using IBM's Viavoice to control Winamp via a program that takes advantage of Winamp's published API). I've found it's much much easier to do this in Linux because you really don't need a monitor, whereas with Windows it's nearly impossible to check up on what's going on w/o a monitor. On the Linux side you can throw a net card in the box and telenet in (if you're doing development) or even port the console to the serial port (perhaps the one you're not using to control MP3s with) and use your Pilot to check up on what's happening.
  • I've done something similar, but I use my PalmPilot (via a serial link to the Linux box) to act as the controller. The principle is that most of the time you're not changing what's playing, so it's not too much of a pain to use the Pilot as needed. Right now I just have stop/pause/skip, etc, and it plays the whole disk randomly otherwise. However, I plan to add the ability to select albums (each dir can be an album for instance).

    I brought this to a party and connected it to a stereo and we had music for the whole night off 1 CD...it truely is cool.
  • I have a similiar project here [iastate.edu]

    Digital optical outputs, and can play from just about any medium. There are actually a lot of these projects around the web.

    How much would someone pay for one of these? I can make aluminum cases like this one (mind you JUST the case) for about $225. (lots of labor involved) but I don't think people would pay that.
  • With a little tweaking on behalf of WinAmp, I was able to get a 66 able to play (without any kind of visualization) without skips. Playing off a burned CD was miserable cause it was a real old cdrom, but locally stored files played fine. Set it up as a player for my little sister...
  • ph33r the effect:

    Do NOT post this on the front-page of slashdot
    Stan "Myconid" Brinkerhoff
  • Grab a window and shake it really fast and sometimes you can get CPU usage up to 100% (especially Photoshop 5 with a large image loaded)
    Stan "Myconid" Brinkerhoff
  • The German computer magazine c't [heise.de] will have a description, board layout etc. of a hardware mp3 decoder that hooks up to the parallel port in their next issue. They claim it works with 80286 and even XTs. Sorry, don't have more info yet.
  • If people are paying ~$120 for the LCD why not buy a PalmPilot? The original one and not the Professional either. That should cost about the same but now you have a bitch'n touch screen for I/O and does it can do more. IMHO
  • I use an Olivetti Envision;

    P75, CD, et al
    Black, hi-fi component width case
    IR remote keyboard with trackball
    Integrated Video-Out.

    Works fine - connected to Yamaha receiver (Dolby Pro-Logic, five speaker system) and Medium-size TV (52cm). Also connected to a modem, allows internet browsing on the TV.

    A P75 is just enough play 128k MP3s using "K-jofol" - don't expect to be doing anything else at the same time.

    Quite old now.


    Win a Rio [cjb.net] (or join the SETI Club via same link)
  • He said that he didn't solder the 9 keys in
    because he needed to be able to plug a standard
    keyboard into it to perform upgrades.
    I'm guessing that's where the floppy might be used.
    And anyway, why not? :-)
    A floppy drive is only about $10 to $20 and it'd probably come in handy for those 1 min. songs you want to play every once-in-a-while.

  • Check out Advantech's [advantech.com] biscuit PC's. They've got one that takes a socket 7 CPU and has on-board ethernet, sound, IDE, video, everything. It runs somewhere around 600 bucks, but it's a 5.25" form factor and runs off a standard hard-drive power connector (only needs +5 and +12 volts). It's what I was gonna use in my project [cloudmaster.com], but that's more than I wanna spend... BTW, on that page, I'm including most of the plans to do something like this. I haven't gotten it done yet, but hopefully I will this weekend...
  • by Conor6 ( 11138 )
    Sounds like what I was trying to do with my old 486/66 DX2... but the only thing I could play without skipping was 24Kb/s MP3s... forget 128. I wonder if a P100 is necessary, or if a 75 or 90 would do. Any thoughts?
  • Yea, Linux stripped down and booted into single-user mode is pretty lightweight, perhaps U can use VFAT file system instead of ext2fs ? I've never tried it but i'm sure its possible.
    If you strip it down far enough U could boot from floppy disk/Flash, and use CD for storage, and completly eradicate the Hard Disk.
    Other options ? Has anyone tried ELKS (and is it up to the job ?)
  • by Bigman ( 12384 )
    Put in a LS-120 and it could be used for upgrades and uploading new tuned to the HD...
  • I'll build one out, throw Apache on it, write a CGI interface to the player and put it on my network downstairs. Then the world can come and see what is on my playlist and decide what I should listen to next 24 hours a day, seven days a week.

    Just think, I could log peoples selections and see just how bad everyone's taste actually is.

    I'll send a story in once its done and you can all /. my MP3 home stereo equipment. That would be a first.
  • I know that the latest versions of winamp for Windows claim to be able to play without skipping at 128Kb/s on a 486 DX4/100.
  • I've got a friend here with a similar project in the works. Linux on a 1.2 gig scsi hd with a floppy & cdrom plus an lcd. He's making it specifically for the car so he's getting the case custom made (out of clear plexiglass - iMac envy I think). A lot of the stuff is from shows so it's all pretty cheap.

    As far as the linux boot speed issue raised above, our solution is to custom compile a kernel with only basic services and network (he's planning on an ethernet hookup to transfer mp3's) and mount the disk read only. I expect it'll come up pretty quick, and with the disk as RO, you can shut it off hard without any waiting for the OS to shut down nice.

    That's the plan anyway. I'll have to see if I can talk him into making plans available once the final scematics are drawn up...
  • I'm doing the same thing, with more emphasis on look. If I'm going to spend $100 on an LCD, the machine must look spiffy. Heck, the LCD I bought ($120) cost more than the machine I'm using (including graphics card, network card, processor, power supply, shell, and memory). So, my plan is to juice up an old 70's 8-trak/Hifi shell by putting a pentium w/a large hard drive inside of it. My biggest problem now is that I have over 200 CD's and it's hard to keep them all in one place when I'm listening to them in the car, at work, at home, and in the gym. Storing them all on one machine would solve that.

    I'm using a small keypad interface to the LCD, and I'm going to have three modes of selecting MP3's : Random mode, Scroll-to-Select mode, and a search mode that will act like one of those telephone answering systems where you search for someone's extension by entering the corresponding digits of their last name. I should be well on my way after this weekend - I have most of the code written in Perl. I used the POSIX module instead of the C code that came along with the LCD that everyone seems to be using.

    The biggest challenge I see is finding the perfect 70's Hifi/8 trak shell for this machine - look is very important (I'll be using this thing at parties) and I want a non-computer user to be able to use it easily. My objective is to create the most powerful 8-trak machine in the universe. No one else will be able to play 200 CD's worth of MP3 off of their 8-trak. The geek factor of this is great too - I'll be able to telnet to my stereo!
  • i have a old P 90 compaq server for my home stereo, with like 16Mb ram. works great no skips at 160bit rate. i think you might be able to get away with the 486/66 if you stream mp3's to it... dont know, although that does give me a project now...
  • My Town Car mounted Compaq Proliant started life as a 486/66 - with and old 83 mhz Pentium Overdrive chip it plays 320 Kbps encoded MP3 with no trouble at all. I have been using the CAJUN software (http://cajun.current.nu) for several months now with excellent results.

  • Actually, playing audio on an old Creative CD-ROM drive mounted in the trunk works pretty well. It take the deepest of New England pot holes to cause the slightest skip. I expect that playing MP3s from the CD would work equally well, if not better, depending on the buffing. I still have 2 gig free on the hard drive so it's not an issue.

    Plug for Paul B's car audio juke box that got me started: http://cajun.current.nu

  • I like... but whats with the floppy?
  • by cygnus ( 17101 )
    yes! i finally get to be smart for once!

    ADAT actually comes in two different formats. The Alesis version stores 8 tracks of audio at varying bitdepth/rates on SVHS tapes. The Tascam format uses Hi8mm videotapes. From what I can tell, the more film/video people use Tascam more and the strictly music people use Alesis.

    i have a friend that's a producer who has a whole stack of the Alesis ADATs and a BRC (Big Remote Control, i assume it stands for) that looks like something out of Star Trek(*). pretty rad with the lights out and all the lights flashing along to the music.

    so, anyway, you aren't going to be able to play ADAT format music on a normal dat deck of any variety. DAT Hi8mm (**)

    "i feel like a quote out of context."

    * i abhor star trek, to the point of yelling at the top of my lungs and lunging for the remote whenever it comes on. just wanted to get that off of my chest.
    ** BASIC rules!
  • ... a recording engineer and slashdotter who uses 'Low' as an audio quality reference. amazing. wouldn't have pictured that. (btw: low is good.)

    i can see why 44.1 was a slight compromise even at the time cd's were recorded (should have been 48 kHz, but past 24 kHz you get from it aren't you reproducing stuff only your dog can hear?) and maybe 16 bit is sort of laughable now (esp. with those 'DSP' circuits in components that are supposed to enhance the sound but sound like a cheesy-ass digital eq averaging bits to the nearest power of 2). and the concept of some mathematical codec being able to decide what i can and can't perceive is almost facist. but the point of mp3 isn't really to be as 'digital' as a professionally-mastered digital recording. think of them as tapes. and as an engineer, these people aren't paying you diddley when they pirate your music, so aren't you glad they aren't appreciating the painstaking effort you put into making every instrument jump out of the mix and lick you. let them screw themselves.

    "i feel like a quote out of context."
  • mp3.com [mp3.com] has had a list of this sort of technology up for ages. I'm building one myself (who isn't? :) ), but I'm buggered if I'm spending that much on an LCD display. There must be a cheaper way of doing it that involves too much hardware spannering.

  • I use winamp 2.10 on a NT machine with a P2-350, and it uses less than 1% CPU here... playing shoutcast streams all day long... Can't really say it's a CPU-eater...

  • Now folks are attempting to intergrate MP3 players into a traditional Hi-Fi setup, which just stuns me. I think mainstream culture was dragged down quite far enough by the pathetic audio reproduction of traditional CDs, with their damn laughable 16 bit/44.1 KHz "superior digital sound," but now MP3, which is just frightening in its "quality," are starting to become more prevalent.

    Thank you. Finaly some one with some sense. Although I can not lay claim to having any kind of proffesional qualifications, I'm not deaf.

    I really cannot see why MP3 is such a big deal. Sure you can down load it and it doesn't take up much space on a hard drive/CD-Rom, but this doesn't change that fact that it sucks.

    Have any of you people who are talking about plugging an MP3 player into your Hi-Fi ever heard good music? Have you ever listened to a good quality vinyl (or even CD) system? Probably not. Because if you had there would be no way you would settle for MP3.

    Well one `good' thing about MP3 is that anybody out there wanting to start a band and cut a record isn't going to have to bother about expensive things like recording studios and mixing and stuff. All you need is to gather around a simple tape deck, press record and off you go. Then releas it as MP3 and no one will hear the difference.

  • You can mount the linux drive RO, and never need to fsck. Problem solved with bad shutdowns.
    drop 32 megs of ram in the system. Do everything in memory.

    Single use computers could benefit from the flexibility of Linux easily. Just recompile without all of the unecessary services.
  • I believe this device is supposed to stay in the home, not in your car. But yeah..unless your CD-ROM drive has electronic shock protection (like on those discmen), I wouldn't think it could stand the vibrations and jarring from driving on the road.
  • This is great! I think I'm going to steal your idea and set up a server like this. Also, implement an upload through apache or ftp so people can add mp3s to the available list of songs. Then broadcast it on internet as well as feed it though the speakers so I can listen to some tunes with thousands of my closest friends :-)
  • I'm not a guru with electronics, so i decided just to use a TV-out capable gfx-card, place the minitower computer in a small closet near the TV, controlling it via an infrared mouse+keyboard(mainly).
    I've placed the DVD-kit and a tv-out voodoo1 card in it too ..

    The main problem with this setup, and with all the other solutions on these pages so far:


    ordinary cdrom (makes a lot more speed-noise than an ordinary cd-player)
    + the fan

    I'm so annoyed with it that I have just ordered a stand-alone dvd player :)
    Which in fact is a cheap-ass one too:

    One final note:

    I thought that I would be using the computer for playing mp3's as well, but since the setup was ready I have only used it a few times.
    The point is that I like to have control with my mysic-playing, and therefore still uses my main computer (attached to the stereo) for mp3-playing.

    I'll say that you have to make some serious considerations before building a stand-alone mp3-player.

    just my 2 cents.

  • Does anyone know if you can read standard Digital Audio (48kHz x 16 bit, 44.1kHz x 16 bit, 32kHz x 12 bit) from ADATs on a computer SCSI DAT drive? Would this just require some lowlevel SCSI programming (a la the SCSI-Programming-HOWTO)?

    -- A wealthy eccentric who marches to the beat of a different drum. But you may call me "Noodle Noggin."

  • Hmmm . . . I think the idea is that a lot of music can be stored in a small amount of space. People want it to be portable. As an aside, not many people understand my love of LP walkmen, but then I am 6'4"; the 200 watt amp and the 15" drivers don't look too out of place. Then there's the Honda generator on the skateboard dragging behind me . . .

    People also want it to have a reproducible sound, i.e. its going to sound the same each time. Granted, I can tell the difference 'twixt a new vinyl album and an MP3, but it's not really that distracting, except to someone such as yourself who makes his living at this. In that clean room environment the LP should sound superb, but otherwise [POP!] [Crackle!] [ZZZZIP!] In that clean room environment [Crackle!] [POP!] the LP should sound great, but otherwise [POP!] [Crackle!] [ZZZZIP!] . . .

    See my point? Relax. Don't take it personally.
  • Fair call.

    But, does a French chef not sometimes stoop to letting his wife cook sometimes or eating ? etc

    I LOVE music, have a reasonable ear, played in a band for many years (albeit a mediocre one), nearly cried when Led Zep, Jimi etc came out on CD 'cause it did sound crap...

    Now, I work from home programming. I have a nice components setup in the loungeroom, but realistically can't have it loud enough to hear it continuously in my office (sounds crap through walls anyway), don't want to move it into my office ('cause it's nice to kick back in the loungeroom), don't want to buy a whole new system, hate having to walk backward and forward changing CD's to the loungeroom (I have tried it :) )....

    So, having a dirty great HD full of whatever I want to "listen" to anywhere accross my network without having to get up, walk to the loungeroom for every CD change, and all of the other things above, is kind of cool.

    It is nice to hear someone stand up for what they love though :)

    Just my AU$0.02 worth...
  • I'm acctually working on a project that's quite similar. I've got a p90 under the passenger seat in my car, playing mp3s. The p90 plays any quality I've tested (up to 192kbps) just fine, with a bit of room to spare. I'm hooking up an LCD as well (www.matrix-orbital.com) and an IR remote control like a TV remote. I tried a 486 DX2-66, but it doesn't play 128kbps without downsampling. I'm using mpg123 to play, and it's got an old one speed caddy-loading cdrom. I also managed to find room to cram an old 512K Trident video card, and a PCI network card in there. It's running a *very* stripped down "distro" of linux... no /sbin/init... runs a bash script instead. =) If anyone wants more info, send me a line and I'de be happy to reply.

    Derek Lewis
  • set up shout/icecast, let people find you with MP3Spy, broadcast to them and share your music with the world.

    If you haven't (and you probably wouldn't if you don't look out a Window) seen it MP3Spy is the coolest piece of software ever.(my new siguote)

    Especially now that I found a Phish [umn.edu] channel all else is bliss.

  • by rippy ( 31757 )
    The floppy enables the sneakernet for those really short songs.
  • I have a P75 running Windows (hey... it was free)
    and dedicated to running winamp... plays full
    bitrate mp3s with no problems.

    anyone know if a P-60 or P-66 can do it?

  • If your motherboard is fairly new, you can just burn yourself a bootable CD - I burnt one with a teeny bit of dos + a dos mp3 player, and it's great. Just switch the pooter on, and drop it in before the thing gets past its memory check. It was a bit fiddly setting up the generic cd-rom drivers ,and figuring out just exactly which drive letter the cd-rom got (not the boot image, that turns into a virtual floppy, but the actual mp3's) , but I had a bit of a poke around with a win98 (gasp! shock! ack!) cd, and it was no big deal.
  • Ah, the voice of a purist! Lets think about things here :

    The average person's "Hi-Fi" isn't :-)

    The average person doesn't *really* care too much about quality (to some extent) , they just want music. (oh , and generally LOUD music please)

    So does the average person , who just wants music whilst partying / reading / doing the housework / driving their car care? Probably not.

    Yes, mp3's mangle the sound a fair bit.
    I am willing to trade off the loss of fidelity, for the simple fact that you can jam (and 'jam' is probably the most approprate word) 12 hours on music onto a single C.D. No, it's not *perfect* music. The AM radio in my car is also woeful , but I still listen to it - and mp3's tend to sound a lot better than ol' AM.

    Nothing in my "hi-fi" system comes anywhere near perfect, the listening conditions are nowhere near perfect, and lets not forget my poor old industrially-deaf ears. Why go to extreme lengths to get the most accurate reproduction , when most people sadly don't even notice.

  • I found mention of a group developing at Linux based car stereo for MP3s. It was portable, and could be removed from the car for stand-alone play or to attach to your home PC for downloading to the internal HD. The URL was www.empeg.com but as of today, I couldn't connect to it. Looked like these guys were almost ready to go to market a month ago when I checked.
  • definately, i agree... its not that i couldnt do it myself, because i am going to try to make something this summer, but if there were kits around i could get my hands on one after i screwed up my own system, therefore makeing my recovery from disaster alot less stressful. :) does anyone have any other kool web-sites that deal with this topic? if so leave a comment!
  • An engineering friend of mine has wired a similar setup into the trunk of his car. Custom power supply, lcd monitor and keypad on the visor and a 3Gb disk. This does indeed seem to be the
    perfect home for servicable-but-retired components.

FORTRAN is the language of Powerful Computers. -- Steven Feiner