Pretty sure it's a theremin in this song...

It begins to fade in at about 1:51 in the song "Make Light" by Passion Pit.

http://www.youtube.com/watch?v=frHHS5FZWnM

It sure sounds like a theremin but I didn't see one in their set-up.

I'm going to resume my habitual role of Theremin Skeptic. The vibrato is so fast--and so absolutely regular in rate AND depth--that I'm sure it's one of the keyboard synths, using a patch with a fast, wide vibrato and ample portamento.

That's not a theremin. It is one of their keyboard synths or modules - possibly the Roland. I have a Roland that will make that type of sound.

I agree with coalport. It's a keyboard with pitch-bend, and vibrato wheels.

In fact, they even show a Roland keybard in some of the stills.

I have an old Kurzweil midi-board which has pitch and vibrato wheels.

There was absolutely no variation in the vibrato rates in the tune.

Brief info:
The urban romance "Ya yekhala domoy" ("She was travelling home...") was written when Lev was 5 years old.
Lyrics and music by Maria Puare (1863-1933), the Russian actress and singer. Her grandfather was a French soldier who had stayed behind in Russia after the 1812 war.

Versions:
classic by Pelageya: https://www.youtube.com/watch?v=LEKe8cf1Gw0

country folk by Zhanna Bichevskaya: https://www.youtube.com/watch?v=thSOQIsxG1M

rock by Diana Arbenina: https://www.youtube.com/watch?v=kATd7f3aV-E

 

"...at the end. Our member Martel had noticed it as  an "idealy soft sounding"."  - ILYA

Here's my noob stab at the Theremin part: Я ехала домой.mp3

It sounds like a sine wave with a bit of level overload (clipping) here and there.  I like the ambiance of the recording in the video!

bravo dewster!

Well, the link has been deleted, but I did find the song, it most likely is not a theremin.

Back in the old days, 2001, I used a Yahama delay unit that did produce perfect vibrato at any reasonable speed, on the album "No Vocals Please" (progressive theremin at times - recorded live with two Korg Synths backing the theremin).  

I believe it was a YAMAHA E1005 Analog Delay Chorus, they have one at eBay ($179) if you get tired of doing it by hand. I used it since my right hand was crippled at the wrist making manual vibrato painful with a very short endurance. 

Nothing like perfect vibrato, except what makes playing the Flight of the Bumblebee on a theremin possible.