tone track - vol diff hard left vs hard right

Using 1.3.12 and playing a single track (tone generated) the left channel sounds louder using the sound card (SoundBlaster 24bit Live) but the right channel is louder using the motherboard chip (AC97).

I tested with two sets of speakers with the same results.

The difference is not dramatic but it is detectable

Shouldn’t the volume be the same at both ends? If so, what is needed?

If you use a monotone test signal there will be a spatial interfernce effect between the two speakers, due to constructive and destructive interference.
So a slight difference in the position of your ear ( a few mm) in this interference pattern can produce an extreme change in the volume heard.

If you use white noise as a test signal you can avoid this interfence effect.

Little surprises me when it comes to on-board sound - this is one place that virtually all PC manufacturers cut corners.
Re. the SoundBlaster - this is still a budget card, but I’ve used a lot of SoundBlaster cards and the sound quality is usually surprisingly good for the price, so I’ll be a little surprised if it’s due to a fault on the card (though this is by no means impossible).

The first thing to check is the sound card settings - somewhere in the SoundBlaster mixer/control panel there will be a “pan” adjustment - check that is dead centre.
Another thing to check is your speakers - if possible, reconnect them so that the left and right speakers are connected to the opposite channel - if the same speaker remains louder, then the problem is with the speaker and not the sound card.

Check that all of the electrical connections are clean and well seated. “Contact cleaner” is very effective (though take care close to plastic parts as some plastics may react badly or even melt). An alternative to contact cleaner is Vodka - it is an effective at degreasing - for mini-jack connectors, dampen a lint-free cloth with the “cleaner”, grip the jack plug firmly with the cloth and twist the plug- take great care not to put any strain on the cable. Carefully but firmly push the plug in and out of the socket a couple of times to achieve a clean and secure contact.

Check the position of the speakers - a loudspeaker close to a wall, or in a corner, will be noticeably louder than one that is away from walls (particularly the bass).