Question on PCM audio import

Hello, I’m new on here but not to Audacity. Still though, I’m having a lot of trouble importing some particular files. They’re .snd files, and the problem is they require two import methods, and one I cannot figure out. Imported as 8 bit signed, at 8000hz, parts of them sound great and how they should. However, the other parts are sped up. So, I import again at 4000hz (still 8 bit signed), and they’re the correct speed but sound horrible. Similar to how it would sound if I imported the files as 16 bit signed instead. This to me, says I need to import at 4 bit, but there’s not an option for that. Well, I read up, and found ADPCM is 4 bit, but importing as ADPCM creates audio that is extremely clipped (and still has background noise regardless). I’ve tried every other Raw Import method possible, but nothing works. Does anyone have a clue of how this could be converted correctly? Is there a program that can convert any type of PCM beyond what Audacity can import? The audio is from an old pinball machine circa 94 if that helps in anyway. Can I use SoX audio converter to convert it? If so, can someone help me do so? Thank you so much,


.snd files could be a proprietary “Apple” thing … Digital sound file formats using the .snd extension - Wikipedia

Apparenty sox will convert a type of .snd file

The current release handles the following audio file formats:

  • Raw files in various binary formats
  • Raw textual data
  • Amiga 8svx files
  • Apple/SGI AIFF files
  • SUN .au files
    o PCM, u-law, A-law
    o G7xx ADPCM files (read only)
    o mutant DEC .au files
    o > NeXT .snd files >
  • AVR files
  • CDDA (Compact Disc Digital Audio format)
  • CVS and VMS files (continuous variable slope)
  • Grandstream ring-tone files
  • GSM files
  • HTK files
  • LPC-10 files
  • Macintosh HCOM files
  • Amiga MAUD files
  • AMR-WB & AMR-NB (with optional libamrwb & libamrnb libraries)
  • MP3 (with optional libmad and libmp3lame libraries)
  • MP4, AAC, AC3, WAVPACK, AMR-NB files (with optional ffmpeg library)
  • AVI, WMV, Ogg Theora, MPEG video files (with optional ffmpeg library)
  • Ogg Vorbis files (with optional Ogg Vorbis libraries)
  • FLAC files (with optional libFLAC)
  • IRCAM SoundFile files
  • NIST SPHERE files
  • Turtle beach SampleVision files
  • Sounder & Soundtool (DOS) files
  • Yamaha TX-16W sampler files
  • SoundBlaster .VOC files
  • Dialogic/OKI ADPCM files (.VOX)
  • Microsoft .WAV files
    o PCM, u-law, A-law
    o GSM
    o RIFX (big endian)
  • WavPack files (with optional libwavpack library)
  • Psion (palmtop) A-law WVE files and Record voice notes
  • Maxis XA Audio files
    o EA ADPCM (read support only, for now)
  • Pseudo formats that allow direct playing/recording from most audio devices
  • The “null” pseudo-file that reads and writes from/to nowhere

Thank you, as for Apple, I don’t think it is being from a pinball machine in '94. Wikipedia says other programs used these files also, unfortunately it seems .snd is basically an Apple format now, but used to be a more generic format. If all else fails, I’ll find a program to open Apple .snd’s and see if that works. About SoX, are you familar with it? I have it installed but I’m having trouble with it since it’s not everyday I use the command line for something. (Or every month for that matter lol) Thanks so much, between it possibly allowing me to import PCM differently than Audacity, and the NeXT .snd file mentioned there, I think I have a good shot at this finally, thank you again, I’ll try to get SoX to convert my file but any help would be appreciated if you’re familar with it, thank you though


Sorry I haven’t used SOX,
I have used a free programme called Gspot which analyses audio (& video) files and tells you what codec is required to play them, it may identify which type of audio file you have.

[don’t Google “g-spot” if you are using a work/school computer :slight_smile: }

If you attach one of your audio files to your next post* I will run it by my copy of Gspot and report the result.

(* put it in a zip file)


Could be due to variable bit rate.

There are several different versions of ADPCM encoding. I’m not sure which version Audacity uses, but it may be using the wrong one.

Yes that should work.
The command to convert a file to a “normal” 16 bit WAV file is:

sox [i]input-filename[/i] -b 16 -e signed-integer [i]output-filename[/i]

If that does not work automatically you may need to specify the input file format.
The full list of options is here:

If you have Sox installed on a Windows computer you can either run the command from “START > Run…” or you can open a command window with START > Run then type in “cmd” and click OK. It is important that you specify the correct directory path to the input and output files. This is probably most easily done by using the command window and changing the directory to where the file that you want to convert exists.

I downloaded GSpot and I tried but it said it was an unknown codec, but I’ll still upload the file to let you see if you can get it to work. The file comes from the old Guns N’ Roses pinball machine released in '94 by the way. There’s actually 5 files, which have short clips of vocals and guitar and random other noises/samples. It’s kind of just a novelty since it doesn’t sound all that great. One file, however, I cannot import in anyway correctly, I can upload it also if you would like. And variable bit rate never even crossed my mind but it sounds possible now that you mention it. How would I get it imported correctly if so? The file is uploaded though, see if you can figure anything out maybe, thank you so much

I used the command you gave me, modified it of course to point to the file and the output, but it said “invalid argument”. I’ve also specified it as being PCM, among a couple others, and seem to get messages about the encoding not being correct (even though I set it and get no error about that.) I think this file isn’t recognized because of it’s odd encoding. The program looks for .snd for example, and finds that it’s not a normal .snd. Etc for other formats, I’m not sure what I need to do to get it working correctly however. Thank you so much though, if you want to try to convert it correctly, the file is uploaded, thank you though (helped me understand command a little better if nothing else lol should help in the future too) (428 KB)

Audacity 1.3.12

File menu > Import Raw
Use these settings:

Signed 8 bit PCM
No endianness
1 channel mono

Thank you, but that much I already have actually, my problem is that parts of it are sped up and when imported at, 4000hz let’s say, instead, the normally sped up parts are now of course the correct (or nearly correct) speed, but there’s a lot of background noise on those parts. It’s almost as if I were to import the snd file I attached as 16 Bit Signed PCM at 4000hz. Maybe I should say 24 bit even.

I’ll attach an mp3 of the part I’m talking about also, (even though there are quite a few throughout all the files) imported at 8000 and then 4000. The pinball machine itself doesn’t have noise present, unless this noise is covered up by the guitar and fake bass and drums. But as I said, it sounds like it’s imported wrong to me, but I’m within the correct realm by importing as signed PCM. ADPCM imports it correctly also, however it’s extremely amplified, which in turn leads to clipping, and it still has static/fuzz background noise. But thanks also for the Audacity update, mine was beta .11, not .12, so I got the new one :smiley: Here’s the file, and I didn’t import as stereo, I just upconverted the mono import to stereo (since my recording of Microsoft Anna was in stereo). (754 KB)

I’ve no idea what the sound is supposed to sound like, but some parts are recorded at a very low bit rate (slow speed) and if played back at the “correct” speed the sound quality will be very poor especially when combined with the bit depth being only 8 bit. Perhaps it is supposed to be played back at the “wrong” speed?

These are not ordinary “sound” files - they are just files that contain audio data for a game. Exactly what the game does with that data, whether it just reads sections of data, plays them forward or backward, or plays several sections simultaneously or whatever, is just what the game does. There are no guarantees that audio that has been ripped from a game will play like a normal audio file.

Well I’m saying at 4000 hz, it sounds correct. As you put that in quotes, I agree, it’s definitely not the correct speed because the problem lies in it being imported as 8 bit. It isn’t supposed to be played though in 8000hz, the only reason I know this is because you can hear vocals at 4000hz and they’re roughly the same speed as in the original song. I understand what you’re saying though.

And I agree, they’re generically named .snd files, rather than being any normal .snd file (whether it be Apple or NeXT, etc.). They are formatted a specific way in that they’re all 512KB, but still not normally. And the game does play sections simultaneously actually, the vocals and guitar, and within the game itself are basically midi instructions to create synthesized drums and bass guitar at those times also. And of course, I agree there are no garuntees. Most games use either very odd formatting or encrypted files, or both. I’m lucky this is regular PCM (bar the fact it needs to be imported at a lower bit rate.)

So, my question is now, how can I import this, in any program, at a lower bit rate? I honestly cannot get SoX to work, unless someone can do that and show me, I’m at a loss. Are there 4 bit PCM files and programs that support them? I know ADPCM is 4 bit, but Audacity’s ADPCM doesn’t import it correctly. I’m sorry to keep on about this, if no one knows an answer to my question or the answer is no, I’m sorry to have wasted your guys’ time. Thank you so much though,

I’m pretty sure that it’s just PCM and not ADPCM. What’s messing it up for you is they’ve messed around with the sample rates so that the file contains different sections in different sample rates. The section that you posted ( sound to me as if the voice is supposed to be squeaky high pitched because the guitar sound behind it sounds about right when played back at 8000 Hz.

To change the playback rate in Audacity, import the file as RAW PCM 8 bit, then mess around with the “Change Speed” effect.