Now and then we get asked about electric basses that sound like a DB. I heard an Epiphone Rumblekat this evening. Its hollow body and two pickups at the neck make sound almost like a DB. I was told it did, but I didn't think it would be that near.
One day, already 7 pages. This topic is unfortunately evergreen. The informed answer from those of us who have spent the money and the time is that nothing but a double bass will ever sound exactly like a double bass, and no bass guitar will ever be able to do more than cop some of the characteristics of a double bass sound. The scale length and body construction are just too different. To get as close as is possible to get, you need to use as many of the features of a double bass as you can, and that means fretless, flatwounds, and upright technique, at a bare minimum. If you don’t play like an upright player would play, you will never sound anything like an upright bass, even if you are actually playing a double bass.
The “correct” technique taught to electric bass guitar players produces, in my opinion, anemic tone and is wildly different to how a double bassist plays.
What I use is a piezo StingRay on the piezo pickup only, with Rotosound flats, sometimes mutes, and a pizz technique that resembles double bass pizz technique. I use an acoustic resonance enhancement pedal (really just a specialized eq pedal), a compressor, sometimes reverb, and a very clean amp that is also popular with double bassists who amplify. That is as close as it is possible to get, and it’s not that close, but it’s still a good sound.
My other bass is a Warwick Custom Shop fretless short scale Corvette Proline with D’Addario cello strings. I wish it had piezo, but I stupidly didn’t order that option. Someday, I will retrofit piezo to it.