So what is a ramp?

A ramp is a block of wood or plastic (usually radiused to match the fingerboard) placed either in-between the pickups or between a pickup and the neck. Its main purpose is to facilitate a lighter attack by limiting the amount your plucking fingers can dig in..

Here is a photo of a ramp from the front:
ramp
And here is a photo of a ramp from above so you can see the radiused top:
ramp angle view
 
 
What is the main purpose of a ramp?

The real benefits of a ramp (to me anyways) are a consistent attack with a quick recovery time because your fingers are only allowed to go in as deep as the ramp is. Without using a ramp, your fingers go in however much distance they do with each stroke. With a radiused ramp, they all go in the same depth, so your plucking depth and recovery time is equal for all your strokes, and a ramp that is close to the strings can limit the amount you dig in, facilitating a lighter attack.  A heavy attack is still easily produced by plucking upwards through the string or playing over another area where the ramp is not located. It's possible for a ramp to let you play faster, as your recovery time after plucking the string is shortened, but that depends on the player.

It's not as if you need a ramp to get a consistent attack or anything, obviously, but it can help. Its benefits are often more noticeable if you're using three or four fingers to pluck with. Consistency is the biggest problem when using so many fingers, and a ramp can be a big help in that.  It is FAR easier to play using your thumb in addition to your standard plucking fingers when using a ramp. The thumb tends to dig in the most, so putting the ramp there makes the thumb bounce back up when it hits the ramp just as fast as your other fingers.
 

How can they aid in plucking?

A standard rest stroke technique allows your fingers to come to a stop once they hit the string behind them. When using a multi-finger free stroke technique, finding an alternative consistent stopping point is very important, particularly because you will be using so many fingers at once including your thumb, which moves differently than your other fingers. A ramp can make using a multifinger plucking technique like the ones Matt Garrison and Dominique DiPiazza use far easier to achieve. It effectively reduces the distance your fingers can dig in when plucking. It also stops your fingers just after they go through the strings, so it's possible for a ramp to let you play faster, as your recovery time after plucking the string is shortened. I could not play this technique without one.

Why should a ramp be radiused?

Most fingerboards have a radius. A proper setup involves adjusting your string height to match the radius of the fretboard. This means the bottoms of your strings aren't straight across- they form a curve that follows the radius of the fretboard.   Getting a ramp that is radiused to match your fretboard radius is important because a flat ramp will not allow consistent depth below each string; for example, on a flat ramp there will be a greater distance below the A and D strings than there would be below the E and G strings. This will result in an uneven attack- you'd be digging in more on the middle strings than the end strings.

Is a ramp just a way to get away with poor plucking technique?
 
No.   99% of the people I've heard be critical of using a ramp are people who have never used one.  A ramp is a tool to aid your playing- playing music is not a competition where you win points for making things more difficult than they need to be.  The folks who criticize ramps are usually the same one who call fretlines on a fretless "training wheels."  Bassists who play and tour with John McLaughlin, Pat Metheny, Mike Stern, and other master musicians use these tools- unless a critic of using a ramp can boast better credentials than those, their opinions can be safely ignored.  A ramp will provide a consistency of depth that you simply won't get from practicing.  This exact consistency may be of no use to many players, but it is of great value to many other players, and is very helpful when using three or four fingers to pluck with.
 
And how much does it bother (if any) when you slap?

Since I, like most other people, slap in the area between the fingerboard and the neck pickup, a ramp located between the two pickups doesn't affect my slapping at all.

Don't you ever want to play aggressively?

I've found that the very rare occasions when I want to play aggressively, I pluck close to the bridge, not in the center. I usually have better luck not plucking hard anyways- in my experience, I can get a much better aggressive sound when I don't pluck hard, as that often ends up just sounding sloppy.  You can still play aggressively with this technique though- the limit of how deep you can pluck does not affect how hard you can pluck.  And one can still pluck aggressively over a ramp- you just have to pluck across the strings rather than through them.

Do any real pros use ramps?

Gary Willis (the originator of them), Matthew Garrison, Dominique DiPiazza, Richard Bona, Todd Johnson, Damian Erskine, Janek Gwizdala, Hadrien Feraud, Gary Grangier, and Tony Grey all use them, among many others.

How does a ramp attach?

Double stick tape is how I do it- I generally use the Scotch brand foam tape, although sometimes the ramp will be too tall using the foam type, so some standard thin double-stick tape is good to have around just in case. It is non-marring (so long as it’s used properly). Be sure to remove some of the tackiness of the tape first by sticking and unsticking it to a piece of fabric- the adhesiveness of this tape is FAR stronger than you need it to be, and not removing some of the stickiness of the tape can make it hard to pull the ramp off of the bass at a later date. It also adds piece of mind if you’re at all worried about your finish being marred. I’ve taken my ramps on and off many times over the years, and have had no marring issues; my basses also have natural wax finishes.  You can actually experiment with the ramp height by trying out differing numbers of tape layers (both the foam type and the flat kind) to see what works best for you.

Some people build “floating” ramps by having them attach to the screws of the pickups, although I won’t comment on these as I have no experience with them.

You can also have one screw into the body, although this is a drastic modification to your bass and could decrease it’s resale value (if this is an important issue to you).

What size should I make my ramp?


It should be the width of the pickups (obviously), and the height depends on the distance between your bass’ body and the strings. For the best results from your ramp, your bass should be set up with fairly low to low action, and your ramp should be pretty close to your strings. I keep the strings on mine about the distance of two credit cards’ thickness (not counting the raised numbers) from the top of the ramp. Your preference may vary. It is better to have your ramp built shorter than taller if you’re unsure where you’d like the top of it to be- that way, you can experiment with the height of the ramp by adding and taking away layers of double-stick tape. You can fine-adjust by using non-foam double stick tape.

Where can I get a ramp? How much do they cost?

Prices vary…I’ve gotten mine for around $50-$125- you may be able to find cheaper- and on the high end, Fodera charges around $300 for theirs.  Luthiers including Jon Maghini and Rob Elrick make them- you can also ask a local woodworker or luthier to build one for you as it‘s a fairly simple project. You can even do it yourself if you have a bit of woodworking skill, a good sander, and a radiusing block to match your fingerboard.
 
What info should I have when ordering one?
 
You need to know the radius of your fretboard so your ramp can be built to match it.  Make sure you take accurate measurements of the ramp's desired length, width, and height at the crown of the radius (the highest point of the radius).  Remember to leave room for the double stick tape- foam-style double stick tape has a thickness of around 1/8".  You can always make a ramp taller by adding more layers of tape, but it sucks when you order one too tall and have to sand the bottom of one down yourself.
 
I hope this little guide was of some help to some of you out there. Take care, and feel free to ask any questions here.