I'm not an audio/acoustics expert, but I think it depends on the instrument you're sampling.
Here's a fourier transform of a piano playing A3 (220Hz).
The bliptronics website tells me the bands are at: 63Hz, 160Hz, 400Hz, 1kHz, 2.5kHz, 6.25kHz and 16kHz.
If you played A5 on the piano at 880Hz and then you played G♯5/A♭5 at 830Hz, the fundamental frequency from two notes would appear equally between the 3rd and 4th bands on your spectrum analyser, making it really tough to distinguish between the two.
I think when you have enough information like in the image above, it's easy to tell what note is being played. But in the case where you have just 7 bands, I don't think the resolution is high enough for you to tell which note is being played.