Author Topic: MP3 questions. (Read 716 times)

JB73 · « **Reply #15 on:** January 06, 2004, 06:37:26 PM »

Quote

Originally posted by capt. apathy
the tape deck adapter sucks. if you go that route get the 'audio-bug'. it plugs into the headphone jack and then broadcasts to FM, just turn your car stereo to one of 4 channles. about $30-35

ya.. i been looking into one of those myself. you got a link?

capt. apathy · « **Reply #16 on:** January 06, 2004, 10:23:28 PM »

http://www1.dealtime.com/xPO-Mito_Mito_AUDIO_BUG_Wireless

since my cd/mp3 stereo was stolen from my car last summer, I've decided to go with a cheap stereo in the jeep, and use the audio bug with either an mp3 discman or regular mp3 player. (hopefully soon, this no-music thing is killing me)

if the range is good enough this would also allow me to buy cheaper, more disposable boom-boxes for work, and just keep the mp3 player in the tool bucket where it won't get burned up.

miko2d · « **Reply #17 on:** January 15, 2004, 08:22:14 PM »

I've got myself a Nomad Jukebox Zen NX.

So far the only good thing I can say abut it is that it took me one minute to get a support guy on the phone - not that he was able to help me but he was very nice.

My home computer (Win 2000) installed fine. The sofwtare interface is crappy but I figured out which button does what.

I've got a bunch of lectures encoded at various bit-rates - from 16kbs and up. Loaded them into the Nomad and tried playing them. Some play fine, others are slowed down - with corresponding low pitch.
All of them sound great in every single software player I have on my computer - 5 or 6, even the Creative Media Source itself.

On my office computer the software installation seemed to go through fine, but the software does not see the nomad when it is plugged in. The operating System (Windows 2000) sees that it is plugged in and recognises it by name but the device manager claims the drivers are not installed. I've wiped it out and reinstalled several times, same result.

miko

JB73 · « **Reply #18 on:** January 15, 2004, 08:31:56 PM »

bummer dude im sry to hear that.

mine has worked great since day one.

yes i'm using win98 @ home but my buddy's PC is XP and i loaded all the software there too. all works fine.

did you try DL'ing new drivers from creative for the win2k maching @ work?

do you have permissions to add new hardware @ the work PC?

how about on the taskbar... is there an icon for the new device and is there an option to "connect" it (again @ work)?

for the audio tracks... when they are playing slowed down did you check if the EAX settings were on and what they were set to? (there is an option to slow down or speed up audio)

let me know

AKS\/\/ulfe · « **Reply #19 on:** January 15, 2004, 08:34:00 PM »

Quote

Originally posted by capt. apathy
128 kbit/44khz is CD quality sound.

172KB/s 16 Bit 44,100Hz is CD quality.

128 is a noticeable downgrade from CD quality music.
-SW

miko2d · « **Reply #20 on:** January 15, 2004, 09:06:14 PM »

JB73: bummer dude im sry to hear that....

I can install stuff on my office PC - which is pretty much my only way to get phone tech-support, since by the time I get home and sort out the babies, the working hours are usually over.

There is a standard icon of an external device that appears on a taskbar when I plug it in, and it offers an option to disconnect it. It knows the device by name but it is marked as "missing a driver".

The EAX were off originally. I tried the EAX on and off and various time rates. Since it accelerates the play without changing the pitch, there is no way to make it sound like it is supposed to - only to shorten or prolong the torure...

I will try to DL the drivers tomorrow on my office PC. I see that they have a driver update from 26 Nov 2003 that supposedely Resolves the issue of the "Device not connected" and a firmware update from 24 Nov 2003.

If it does not work, I will probably return it.

miko

Pfunk · « **Reply #21 on:** January 15, 2004, 09:46:52 PM »

see my aformentioned post...the software that comes with the Nomad is chit.....try this instead

http://www.redchairsoftware.com/notmad/

sshh · « **Reply #22 on:** January 16, 2004, 12:53:34 AM »

Miko try figure out what is common thing in those mp3s that dont play well. It could be lower encoding bitrate (16 vs 32 vs 64 kbps), different sampling frequency (44 vs 41 vs...), encoded using VBR (variable bitrate) or CBR (constant). Other than that drivers and player OS (firmware) update may help too. But I'd rather try figure out whats wrong with specific files first. Only then update player OS.

miko2d · « **Reply #23 on:** January 16, 2004, 11:30:39 AM »

The driver update cleared the problem of the invisible Nomad.
The firmware upgrade did not help much.

I made a test of a dozen of various kinds of encodings using CDEX. CDEX allows to use the LAME encoder or window MP3 codec.

The lowest bitrate that works seems to be using the windows codec 24kbs/22,050Hz.

The LAME encoder set at that rate or at 16000Hz works too but the actual rate it produces is much higher - apperently one can specify the minimum rate but not the fixed one.

The Nomad just seens having trouble playing anything at 11,025Hz sample rate and while it plays 18kbs/16000Hz files fine, I have no way to encode at those settings.

24kbs/22,050Hz is still 5.3 times more compact than 128kbs rate - which makes moving and storing the files easier, so I will probably keep the Nomad.

Thanks for your advice.
miko

sshh · « **Reply #24 on:** January 16, 2004, 09:58:27 PM »

Glad to hear is works. I'm not sure what you mean by :

Quote

The LAME encoder set at that rate or at 16000Hz works too but the actual rate it produces is much higher - apperently one can specify the minimum rate but not the fixed one.

Is that 16 kbps ? Anyway Lame of course has options to specify lower bitrate (as low as 8 kbps) -b 8 or -B 8 for maximum allowed rate - see here http://lame.sourceforge.net/USAGE

Also there is option to set sampling freq and Lame supposed to resample original file to your wishes --resample 8 for 8 kHz. You may try RazorLame http://www.dors.de/razorlame/ to play with Lame options without actually typing them in the command line and looking up the manual.

Last link for today

http://www.exactaudiocopy.de/ - best CD extraction tool. And quickstart doc for it http://www.ping.be/satcp/cd2mp3-en.htm

miko2d · « **Reply #25 on:** January 17, 2004, 01:31:17 PM »

CDEX uses LAME encoder as a promary MP3 encoder but can also use window codec which happens to be Frounhoffer algorithm.
So I am not using LAME directly but via CDEX. I suspect that LAME allows to set the exact bit rate but CDEX apparently only allows to set minimum bit rate when working with LAME.

16000Hz I mentioned was a sampling rate, not a bitrate. Sampling rathe is how many samples per second are taken from the signal. It should be a bit over twice the desired frequency range, so for reproducing music in the whole range a human ear can hear it (100-20,000Hz) the sampling rate of 44100 is standard.
Other common sampling rates are 22050 and 11025 but any other one is possible.
For speech, 4KHz is sufficient, so a rate of 8kHz or 16kHz is fine.

The higher the sampling rate, the better high-frequency fidelity.

With the set bit rate, the higher the sampling rate, the fewer bits are available for encoding each sample. The fewer bits ised to encode each sample, the greater the sampling error, which is exibited as increase in noise.

Standard .wav files use 16 bits to encode each sample - 32,000 values at 44,100 samples per second.

So there is a tradeoff between frequency reproduction and noise.

Thank you for the links, sshh.

miko

JB73 · « **Reply #26 on:** January 17, 2004, 04:45:12 PM »

umm you know and understand all that and are asking lowley schmucks like me about advise on mp3 players?

~~again hope it works out~~