Learning bass lines by ear is difficult for following reasons

• :The bass tends to become mixed into the overall sound which makes it hard to separate out by itself.
• The bass is very low in the overall frequency range and it's hard for a lot of us to hear accurately down there . This tends to be more of a problem for non bass players than for bass players.

The TR-1000 and TR-400 are digital music study recorders. With these can record some music and then by using the bass isolation feature, you can remove everything but the bass. These two units also have the ability to adjust the pitch up one octave. By combing these two features, you can effectively solve both of these problem areas. Since these devices can also slow the music down, you can isolate the individual notes better.

The LBR-100 is a more specialized device. It is not a recorder but rather a sophisticated filtering devices. One of if's features is a very sharp adjustable low pass filter. By setting the filter low, say around 100hz, you will block out everything but the bass player. This works great even on old records that are terrible in terms of bass recording. This device has other features that are not specific to bass line transcription. This device can also be combined with the TR-1000 and TR-400. It does a better job at the bass isolation feature than the digital music study recorders and the serious musician might want to have both. It has other features helpful for transcribing other instrument parts.