Hammer ons and pull offs.

[xxfaux_punkxx]

how are they done?

From what I've heard you just slam your finger on the string for hammer on's and pull down/release for pull-offs.

So this is what I do but the hammer-ons are inaudible and the pull-offs sound the same regardless of which fret.

any suggestions?

[nightcityburn]

all the notes should be defined, it should be a smooth transition from note to not, much smoother than if you have actually plucked the notes individually. It takes some patience.

[klokker]

Hammer on and pull off in my experience are best practiced together. You don't really slam your finger down, but a firm press and hold should do the job.

Practice until you can get good tone, then hammer on and pull off in one motion with all four fingers. After a couple of years it comes easy!

[DopplerShift]

hammer-ons are usually played after you pluck a different note.

For example, play an open E then hammer-on an A on the 5th fret. Then pull off an open E.

Another example would be hammer-on a 5th fret A from a 3rd fret G.

[lhoward]

There are a lot of sources to learn this. Youtube has a number of items you can check out. Of course I believe Larry Graham is the one who started this technique on electric bass back when he was with Sly And The Family Stone and later, his own band, Graham Central Station. I've always enjoyed how Marcus Miller plays. Some videos I've bought over the years show his technique pretty well. His thumb technique is a true hammer-on (hammering on the string and coming up after the one strike) as compared to Victor Wooten who describes his thumb technique as going through the string and then coming back up under the string with his thumb, so he gets two string attacks which is different action and sound from his style.

There are any number of competent books available to help learn the technique as are DVD's of performances and some specifically directed toward instruction. Hudson Music has some by Victor Wooten. One is his performance at Bass Day '98 which presents his entire performance in which he also answers questions and goes through how he does what he does (at least as of 1998):
http://www.hudsonmusic.com/hudson/pr...bass-day-1998/
They also have one instructional video on slap bass by Bass Institute of Technology instructor Alexis Sklarevski.

Although I'm not specifically a slap player, I have studied and played the technique from time to time. But I'm primarily a fretless player most of the time (when I'm not playing upright) and I don't slap on fretless, But note that Michael Manring can do an interesting approach to that style on fretless.

You can check out any number of growing bass/music camps (Google 'music and bass camps') coming up during the summer months that can provide interesting opportunities. A few years ago, I attended Gerald Veasley's camp which had players like Victor Bailey, Gary Willis, Victor Wooten, Michael Manring, Bakithi Kumalo, and Brian Bromberg.

Have fun.

Lloyd Howard

PS: http://www.youtube.com/watch?v=4JHqeePBq3I&NR=1