Can Anyone identify the instruments used in this piece?

Below is an excerpt from shostakovich's second waltz I recorded using Audacity. I will not post the full piece here as this would break the copyright (laws?).. Well anyway, can anyone tell me what instruments are used in this piece?

Firstly, the oom pah pah part.. What instrument makes the "oom"? A tuba?

Secondly, the main melody. I love the timbre of this instrument. Have only a slight idea on what is it though.. Bassoon?

Then at 0:20 some counterpoint is introduced. What instruments are playing the melody, and which is playing the counterpoint passage?

Thanks.

here's the mp3 link(rapidshare): RapidShare: 1-Click Webhosting

Btw I really recommend using rapidshare when uploading music files. It's more accessible for me. Many other hosts don't work..:P

PS. If you want the full piece, I can send it to you. Just pm me;)

Great Waltz. The Shostakovich Jazz Suites are amazing.

The part seems to be played by cellos and double basses with piano. From my recording, it appears to be pizz. in the opening passage after the beginning two bars.

[EDIT] in subsequent recordings, it even sounds like a saxophone.

Piano? Where?

Mm. 39 on. In my recording, it's quite clear, and even the focal point for four bars of transition.