Hi all,

I've got a question. I'm recording a two hour radio show every week. I set the tuner to 'mono' 'cos I don't like the fm stereo hiss, and record it with a Sony DAT deck, set to 32khz sample rate. I then transfer that data from the DAT to the computer using a Roland UA-1 and Cool Edit. Since the source is mono and the DAT only records stereo, I then use Cool Edit to transform the file to mono. I also edit out all the adverts from the radio station.

So now I've got about 118 minutes of 32khz wave file, about 430mb. I want to encode this to some reasonable size mp3 file of quality consistent with the source. I'm using lame, with the following settings:

-b 96 -m m -h -V 5 -B 96 --lowpass 15.4 --vbr-new -q0 --cwlimit 10

This is per the www.jthz.com/mp3 web site that has instructions for encoding fm radio encoded source.

I know that stereo encoded at 128 kbps yields mp3 files that are about 1 meg per minute. I was assuming that, since I was encoding mono at 96 kbps, I would at least get files that are about half that, or about 60 meg, but instead I'm getting 88 meg files. This seems a bit large, but not overly so. Can anyone tell me if the settings are optimal for this application?

Also, (ok, I have two questions) I have many old copies of this radio show encoded in (un)Real audio, at 20.7 kbps mono. These are rather nasty quality, with lots of aliasing and phase distortion, but they are all I have for the older shows. I've tried using the old version of Streambox Ripper to convert them to mp3, but in order to get the same lousy quality faithfully reproduced I had to use a bit rate many times higher than the ra files and ended up with monstrous mp3 files. Is there a clean way to convert these and retain the same bit rate / file size?

Thanks,

Larry

You're recording it in medium-quality VBR (-V 5, --vbr-new) with the base bitrate (-b) and ceiling bitrate (-B) both at 96? That seems odd and it might be confusing lame. Try:

-b 96 -m m -h --lowpass 15.4 --cbr -q 0 --cwlimit 10

In fact, you might just want to try a basic:

--cbr -b 96 -m m

to make sure it's doing the right thing at all.

the station only adds 2 minutes of commercials every 120?

In fact, you might just want to try a basic:

--cbr -b 96 -m m

I tried that and ended up with a file only 194 bytes bigger than I had, and sounds the same. Maybe it is the best rate...

Thanks,

Larry

the station only adds 2 minutes of commercials every 120?

National Public Radio. I could never listed to commercial radio...

Well, the thing is, it's probably using a full 96 kbps for the one channel. Since 128kbps probabyl sounds fine for FM talk radio, try encoding at 64kbps mono CBR and see if it sounds okay. If you thought you could get by at 96, then try 48, too. There's also a 56.

OTOH, ISTR a bug report that the empeg wouldn't do mono files properly. You might want to test one before you go hog wild.

ahh yes. npr
love it
ive not watched tv or listened to radio in moths, and i dont miss it.

If you thought you could get by at 96, then try 48, too.

I've tried that, and as one would expect, the file size is half. Also still sounds ok. Now to see if the empegs will live with it.

thanks!

National Public Radio

Two hour show... so which is it? "Prairie Home Companion"? Or "What do you know"?

BTW... if anybody is interested, I have nearly two years of "Car Talk" episodes saved in my empeg...

tanstaafl.

It's Prairie Home Companion, which I've recorded for years. Unfortunately, most were on cassettes and lost. The ra files were from their web site, from back when you could download them.

I've seen Whaddaya Know when it came here a few years ago. I'm actually planning on recording it too, and Wait Wait Don't Tell Me and Car Talk as well, but just to listen to them during the week, as I'm always busy on the weekends. I won't archive those...

In reply to:

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Well, the thing is, it's probably using a full 96 kbps for the one channel.

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Probably? It had better be, as that's what was requested! Bit rate is exactly that - how many bits are used to encode each second of sound. If you have a mono MP3, then you'll have higher quality than a stereo one of the same bit-rate (but not generally by a factor of two, as the two channels generally have a lot of redundancy).

In reply to:

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ISTR a bug report that the empeg wouldn't do mono files properly.

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I've had no problems with my audio books (several dozen hours worth) which are all encoded in mono using lame -mm -V 9. I would recommend resampling down to 22.05kHz, as that's the best frequency response you'll get on FM anyway - no point wasting bits on spurious high-frequency noise! My Harry Potter collection made it in at around 37kbps, and plays fine on the empeg (v2.00final).