Regarding how to get the Motown sound (kinda mimics a stand-up bass, very little ring to it), I put LaBella James Jamerson strings flat wound (.110 E) on my '83 4 string Ibanez Musician bass about 10 years ago but only recently have been reading up on him.
One thing that I noticed was that he used a stock P-Bass with a string dampener under the bridge pickup cover. I didn't know that and alway thought that just with the Jamerson strings that I was getting "the sound". Obviously not.
I've seen several homemade examples of various types put on different basses that seem to work but always seem...well, homemade.
Recently I've been on the hunt on how to get "the Motown sound" without putting some foam on my bass or anything that looked like it came out of my laundry room or kitchen.
In my search to find a reliable, easy to use, easy to remove, cheap, and stock-looking method, I stumbled up something that you all be interested in that doesn't require any modification to your instrument, create any type of foam "crumbs", doesn't fall apart or require anything that might damage your instrument.
1) I obtained a black 7.5 inch long by .5 inch wide Velcro cable tie (available at any office supply store).
2) I then pressed on two small strips of industrial Velcro (the fuzzy part) to the non-fuzzy side of the Velcro cable tie to build up the thickness.
3)I then installed the cable tie (with the industrial Velcro on the strings) pretty snugly between the bridge pickup and the bridge.
Note: the cable tie closes with the end being pulled towards the G string.
After playing a bit with it, I discovered the following:
1) Depending on how thick the additional velcro is and how heavy a gauge string is used, you may have to put more or less extra strips.
2) The cable tie can be moved closer or further away from the bridge, depending on the amount of dampening required.
3) The cable tie can be angled a bit to change how much dampening required, especially good for changing the dampening on the individual strings.
3)The cable tie can be installed very tightly or not, depending on the dampening required.
4). After installing the cable tie, I pressed the top and bottom of it together so more Velcro fuzz was touching the strings.
5) A 6.75 inch cable tie length will work fine as well.
Check out Jason Long on Youtube to get a good dose of the Motown bass lines of James Jamerson.
Check out James Jamerson's exact playing position on Marvin Gaye's "What's Goin' On" at:
http://youtube.com/watch?v=Y9KC7uhMY9s It's a live version and a great listen.
If you try it, let me know how it works out.
KC