Ok - hear is my B-100R compared to my '63 B-15N.
First, please excuse the production value. I whipped this together in a half hour and didn't spend a lot of time on anything technical. I've never posted anything on Youtube before, and I dont have a video camera - so I did the best I could with what I had. Second, this is just a demonstration of tone, not a demonstration of playing ability. (i.e. dont bag on my playing! lol) You may want to listen to this in headphones or earbuds, as a lot of the low end doesnt seem to translate well on laptop speakers.
I recorded with a Fender Japan 62 Reissue P-bass with flatwounds and foam under the ash tray, running into a Fender tuner acting as a splitter. I set the laptop up about 4 feet in front of both amps, and just used the built in mic to record into Samplitude 2496. I didn't tweak any EQ or add any compression etc... to the wav file. Because I just recorded with the built in mic, you do get a lot of room noise and the acoustic attack of the strings themselves on the bass.
I set the EQ flat on the B-15, then tweaked the EQ on the B-100R to match the Portaflex as much as possible. You'll see a slight bump on the bass, and the treble and high mid are rolled off just a bit. Standing back in the room, you'd be hard pressed to tell the difference - especially if a band was playing. However, on the recording - the B-15 sounds much bassier than the B-100R. I assume it's because the mic picked up what was right in front of it, and the Portaflex has it's ports on the front. The B-100R on the other hand is ported on the back, and if it's sitting up against a wall or being micd from the front - you wont get all of the low end being pumped out into the room.
When I get more time I'll work on something a little more "produced". Until then, thought you might like to check this out!