There's virtually no such thing as a non-resonant floor unless specially treated. All floors vibrate, even rigid concrete floors which are steel/concrete structures having a natural vibration frequency and resonance characteristics. Micro-vibrations, especially the higher-frequency acute vibrations that cause a lot of glare in the music, travel readily through concrete and other rigid materials. Also, some loudspeaker-generated vibration that "drains" from the speaker cabinet to the floor will reverberate right back up the spikes the way they came, introducing some coloration and glare into the music; also, speaker-generated vibrations, becoming floor-borne, can infiltrate the audio rack and sensitive audio components.
An appropriate isolation/decoupling approach is virtually always sonically superior to spiking or otherwise coupling to the floor. (Not trying to isolate with rubber, Sorbothane, vinyl nitrates, or other materials that have resonance issues of their own.) Compared to spiking, isolation with Herbie's Audio Lab's Gliders virtually always produces a superior result, with better bass definition and subtle improvements throughout the audio spectrum.
Herbie's Audio Lab