I just moved in to a very small rectangle room, the longest length only 310cm
So according to the rules of 38% listening position, it'll be at around 117cm
This is really crazy close to the monitors if monitors placement at around 1-1.5ft away from the front wall.
What's your opinions, advices, suggestions to place the speakers & listener?
p/s: Can I just make it the other way route (calculation)? Listening Position at 62%
Haha. it seems can do nothing, haha
Not much you can do - except find a larger space.
Without knowing all the dimensions (L/W/H) or the materials used in the construction, or the location of the room in the structure (first or second floor, etc) ... essentially what you have - if I'm relatively close on the metric conversion in my head - is not much bigger than a typical walk-in closet.
Others here on RO may have suggestions, unfortunately I do not. By and large, The smaller the space you are in, the more acoustic issues you will have.
While I'm not normally a proponent for mixing with headphones, This may be one of those scenarios where you should get a really good pair of cans (good ones) and reference your mixes in that way.
Erm, this seems a bad news ya. wahaha...
310cm x 210 cm x 270cm (H) is the room size, with Rockwools 2 inch on walls
Seating @ 62% from the back instead of 38% from the front wall
5 inch monitors