The Cort Curbow requires some degree of explanation just for the name. It was designed by the late Greg Curbow, a luthier well-known for extended range basses. Curbow doesn't manufacture this bass, however--they pass that on to Cort, maker of lots of odd low-end instruments. The Cort Curbow is also interesting in that it's not made of wood. It's actually built from luthite, a kind of synthetic foam that's supposed to sound like wood while being much lighter. The bass certainly looks futuristic enough.
Here's the problem, and it's a killer: the Cort Curbow has serious dead spots. Dead spots occur when the materials and construction of an instrument resonate with the strings, so that the vibration energy is dampened. The effect is basically that the note fades almost immediately. Almost all basses have dead notes somewhere, some worse than others. Fender-style basses are usually dead between the 7th and 9th frets on the G string.
The Cort has dead spots on either side of A# all up and down the neck. That means within a few frets of the 13th on the A string, the 15th on the G string, and the 8th and 20th on the D string. In fact, I'm not sure that they're dead spots in the traditional sense at all, because they move when the strings are tuned up or down. It's more that the whole bass resonates at multiples of 440Hz.
Is that such a problem? After all, the Cort Curbow is a cheap bass, and incredible sustain is perhaps more than we could expect. But dead notes to this extent also cause problems for someone like me who plays chords or double stops on a regular basis. Play a B chord up on the neck, and the B's decay, leaving only the fifth playing (in this case, F#). The problem is made worse with distortion, so that my fuzz chords lose important notes, and sometimes turn into different chords altogether. Clearly, I can't just work around this, never playing an A chord. That's a fundamental flaw in the instrument.
If I got a bass with this problem once, I would (and did) write it up to a manufacturing error. But this is the second Cort Curbow that I've ordered. Perhaps it was silly to try again, but the first instrument came from an online retailer and might have been faulty. For the second time, I ordered directly from Curbow, the luthier. For a price premium over the online shops, Curbow sets the Cort-manufactured bass up in their own shop. I wrote to them, mentioned the dead spot problem, and asked them to check before they shipped the new bass out. Getting a second bass with the exact same problem, down to the location of the dead spots, implies that this isn't a manufacturing problem--and indeed, the bass itself is very well-constructed. I'm guessing it's actually a design issue, probably centered in the luthite material that Curbow doesn't usually employ.
Whatever the explanation, it's not a usable instrument. I hate to say that. I really wanted to like the Cort, but all those extra frets don't do any good if they can't be used to play several notes from each octave. Return policy permitting, I'm sending it back to Curbow this weekend.
UPDATE: Curbow doesn't issue refunds. They're in discussions with Cort, but I'm not filled with confidence that this will end well. Does anyone have any suggestions on how to alter this bass so that it won't resonate at these frequencies? I'm considering replacing the body with re-routed parts from an Epi SG or a cheap Ibanez.