For the sake of hearing the notes and intonation I have use the amp for most of my Gigs all my life with the exception of the Orchestra stuff and some pit jobs. When my Gilkes came out of restoration I had a Gig subbing with a trio in a Holiday Inn. I thought I might be able to try it with out the amp but I brought the amp anyway. I used an old AKG160E studio mic I bought back in the 70s for home recording and I wrapped foam around it and slid it between the bridge feet. I tried 2 tunes first without the amp until the pianist/leader said, maybe we need a little amp on it as he couldn't hear the pitch as well as he could feel the Bass. The drums across the other side of the Piano had the same problem. It felt good but the Bass is just too deep sounding. I was sitting about 2-3feet off the wall and the Bass was 4-5 feet from the wall. The room was mostly carpeted with maybe a 10-12ft ceiling and not a big room holding maybe 20-25 tables with a small dance floor on the side.
I think the individual sound of the Bass, how it's set-up, the player and the room makes a difference. Currently my Bollbach is out on trial/loan and I got a call about its non-amped sound. The Bassist was playing a gig in a small lounge without the drums for the first hour of the gig. He was not using an amp and could be heard just fine. When they moved to the bigger room with the drums set-up, he didn't have time to set-up the amp before the band started to play. He started playing without the amp and even with the drums he was heard just fine.
Now, what's fine for you may not be what's fine for me. Everything matters including the ears. I like to hear my pitch as best as possible. Even in the orchestra, I have pinched my own beard under the string while leaning close to hear my intonation.. Ouch.. in-tune but I hurt myself..
On one Duo Gig I did at the Philly Art Museum Sunday Brunch with Vibes & Bass recently I was able to hear myself just fine. I know for sure it was the room because my Bass although is fairly loud, is not usually that loud in other places... go figure..
