So let's conduct our own Fretless Bass Market Survey
1) are you a regular fretless electric bassist? - Y/N
2) does the fingerboard or top edge of your favored fretless bass have lines, or is it fully unlined? - Lined/Unlined
3) all other things equal, if you bought your next fretless bass from a brand that offered the choice of either a Lined or Unlined fretless neck, which would you purchase? - Lined/Unlined
4) if you only had the one choice (as with Godin) of your less favored fingerboard preference, from your favored fretless bass brand, would you buy one? - Yes/No
5) Please describe your view on this subject? - ________________________
1. yes - at times have rarely used a fretted instrument (both 4 and 5-string)
2. fully unlined. I won't own one with lines (reasoning below). Does have dots on the edge that correspond to the "fret" positions @ 3-5-7-9-12-15-17-19-21-24
3. won't buy a lined bass - won't even consider it
4. see 3
5. I have strong views (obviously). Way back in the day my first electric fretless was a converted fretted bass. I had the frets filled with rosewood (on a rosewood board) so they were subtle. I was also learning upright at the time. I doubled for about 10 years also playing fretted. In '00 I found a Zon 5-string fretless with a Lightwave system that I fell in love with. It was 5-string, unlined. I'd never played 5-string at that point, but dove in with both feet. Played that bass for almost 10 years, rarely touching a fretted. Last 7 years I've gone through a number of other fretli, currently have a Smith 5-string and Rob Allen 4-string. Both unlined.
I'm a firm believer that lines on the fingerboard are an impediment. The reason being that we (humans) have a long evolutionary history that has instilled the primacy of visual cues into our brains. The problem is that with a fretless bass you're trying to make a sound, not match a visual marker. Combine this with the imperfection of intonation, gig distractions, etc, relying on the line as your main reference is problematic. I think that no lines (dots as a rough indicator) forces you to rely more on your ears, which in the long run gets you to a stronger place.
There are obviously pros and others who swear by lines, and more power to them (no need to cite examples). For me it is a clear answer, but I think that in general no-lines is a better path. That is my opinion, totally YMMV. There is no absolute "right" answer.
