...with regard to the processing of left and right stereo channels.

I've noticed that the Lame encoder offers the option of either stereo, joint stereo, forced stereo, or mono.

But I recently downloaded some mp3s from a friend that are kind of odd in my experience. When I check the tags, it says '2 channel'. Mind you, the friend in question isn't exactly audio/tech savvy. When I asked her about it, she replied "I just use MusicMatch Jukebox for encoding". She did know that MMJB uses a version of the Fraunhofer codec (I was surprised she knew that) but not much else. So I'm left wondering...what exactly does '2 channel' mean? Is that just another way of saying 'stereo'? Or is it something else entirely?

TIA for any info.

2 channels just means that it is not mono. It could be any of the stereo methods.
To see the method used you can use 1 of following programs:

• encspot
• http://vbspot.sourceforge.net/

Hmm... Well, 2 channel sounds like dual mono to me. That means that for 128 kbps for example, each channel gets exactly 56 kbps. Dual channel recording is often used for bilingual speech or whatever.
Which software did you use for displaying the tags?

I use EncSpot. Is that bad?

But I'm not getting the 2 channel info from EncSpot. I'm getting it by reading the tag info directly in WinAmp.

what does it say when you right click the file in encspot and choose "details" --> "mode"=?

mp3 format has:

Dual mono
Stereo
Mono

Encoders can use the following stereo techniques:

Stereo (left right)
Joint Stereo (mid side)
Intensity Stereo (for low bitrate)


If you know the VCD standard, you know some discs contain 2 languages. And that uses mp2 dual mono. Fhg designed mp3 to replace mp2 and be the audio for a similar use, it just didn't happened that way; but people found a creative use for it rest is history.

So you can figure by now why dual mono mode is so rare, since people used mp3 just for music instead. It is of course of less quality than the Stereo mode, because it can't share anything between channels, and its exactly half the given bitrate for each channel. Instead, the stereo modes can trade a few bits from one channel to another.

Oh. Sorry. I never got an e-mail that this post was replied to...weird.

Ok. It says 'dual channel'. Is that dual mono? Or is it just some other form of stereo? I'd really like to know and I've never been able to find a definitive answer.

One site I found here states quite plainly that "Dual channel files are made of two independant mono channels. Each one uses exactly half the bitrate of the file." But another site here states that dual channel mode "encodes each channel completely separately." Then later in another paragraph the same site says refers to "an encoder capable of producing simple stereo or 2 ch files (dual mono)." So I'm really confused. Is 2 channel dual mono. Or is it really just another form of stereo encoding?

I haven't found much else. So I'm turning to the experts at Hydrogen Audio for answers.

Amongst the recent forum updates there seems to have been a strange setting change which means that although you get subscribed to topics you post to they are set to no email notification.

Click My Controls and then on the left hand side under Options click Email Settings. You will probably find that "Enable Email Notification by default" is ticked but the "default type" is "No Email Notification". Change this to Immediate or Delayed Email Notification (I'm not sure what the difference is). This will fix it for topics you post to in the future.

To change existing subscribed topics so that you get notification you need to go to your list of subscribed topics and you will see the notification at the bottom of each after the word "Type: ". Check any that aren't set for email notification You can then change the notification for these at the bottom of the page: where it says Unsubscribe With Selected you can drop this down and choose instead to change the email notification of the selected topics.