Several ways to do this. I personally like using a fairly-neutral large diaphragm condenser (Shure KSM32) about a foot away from the bridge, aimed at the fingerboard. Others will stick a good ol' 58 wrapped in a towel wedged in between the body and the strings, behind the bridge.
The last time I asked an upright bass player if he had a pick-up and if so, could he bring it to the gig, I got what I deserved. He DID bring his pick-up...a '92 Ford F-150 !!! I know, that's a bad one....sorry!

You need to do a stereo recording, yes? So you will need more than one mic.

The old "wrap it in a towel and stuff it in somewhere" is not too popular with bassists who are sensitive to how that changes the sound of the bass, and the reasons for doing that really do not apply in a recording session.

You should experiment with 2 mics-- one in the bridge area (but not really looking in the f-hole-- too boomy) and another hogher up and on the other side of the fingerboard.

Depending on the room, another pair fiurther out would give some space to this. You want an image that neither makes the bass a millimeter wide nor wall-to-wall.

If I were doing this I would use an SF12 a few feet away with a DPA4061 with the DPA string mount just below the bridge and mix to taste.

You do not mention what mics you have available.

Rich

condenser : a couple of rode k2 vacuum tube and a couple of akg c 1000s

dinamic : md 521 blackfire , sm57, sm58

preamp: dbx 386 vaccum tube pre, tlaudio eq1 vacuum tube pre and eq.( blue series)

From the info you have given I think the best thing is to plan on taking at least 30 minutes trying your mics in different positions. You know what frequency regions your various mics are best with.

Until a few months ago I would not have considered a dynamic, but a bass player brought along an Electrovoice RE27 and it sounded fantastic!

Don't use any compression or EQ while recording-- save it as an option.

Let us know how it goes.

Rich

Recorded a Bluegrass quartet as a favor to some friends last Friday. It was a live (amplified) performance. The bass player had a pickup installed, which I used (shared with the board) to minimize the amount of gear in already tight quarters. It was the first time I had done that, rather than mic'ing the bass.

It worked OK. Dry, of course, but that's not hard to deal with and all the tracks (vocal and instrument) were close-mic'd anyway. The only thing that surprised me was the amount of higher-frequency (compared to the bass) mechanical noises coming from the pickup. Able to manage that with some LP EQ.

thank's a lot

Every time I mike a bass close to the f hole I hear *everything* else going on in the studio. It's like the bass is just a big refective baffle to all the sound waves in the room. One time, it was so bad that the 'noise' signal (other instruments) were louder than the bass itself.

Isolation has been a very tough nut for me to crack. I like the idea of positioning the mic toward the fingerboard to pick up those sounds and lower the droning boom.