I'm still agonizing over what to do about tone. Matthijs and SebbyNC, I love the sounds of you're getting and wish I could get something close. What do you use to amplify, Sebby?
Maybe you have a problem with matching impedance between you Wav4 and your amp.
For recording or amplifying my Wav4, I use the same thing as I use for my electric basses: a Boss ME-50B multieffect. In fact for the recordins you heard, I used the ME-50B simply as a preamp, because it has a 1Mohm input for taking the high impedance output of the Wav4 adequately. Otherwise I let all the settings flat with no EQ, no effect. It's a very nice unit, worth to check out if you use effect stomp boxes or units for your electric bass.
I also put D'Addario Helicore Hybrid medium strings, which improved the sound a lot over the stock strings. Also, I always use the Arco mode, which sounds closer to an upright bass that the Pizzicato mode.
An easy and cheap solution for impedance matching, is to fit a small buffer preamp into the control cavity of the Wav4, for example CafeWalter sells his PZP-1 preamp for about $50 shipped within the US ([Invalid or Expired Link Removed]).
Finally, one thing I don't like very much with the sound of the Wav4 is that it has a very strong attack (you can hear it on the first recording), and I found later that using some compression to lower the transient attack gives a smoother sound. When playing live, I use my ME-50B to tweak the EQ (most PA's tend to emphasize the high end too much, so I EQ my highs down, and I add more mids for more thud) and add some compression. People in the crowd always say they are very impressed with the Wav4 which then sound very close to an amplified acoustic upright.
So, in few words my advice is :
- have good strings
- use the arco mode
- match the in/out impedances (preamp with at least 1Mohm input)
- to further improve: some compression, some EQ to taste
<-- I use this because of the irony of it all ^_^