Creating speaker baffle from cardboards glued together to increase thickness

At your risk. A 4mm baffle was created by glueing 2 layers of 2mm by PVA water soluble glue. Size of panel is 50cm by 70cm. Promissing sound. More thickness, say 3 ply increases bass as a thicker matterial insulates more the bass. But for some reason 4 ply sounded a bit bass heavy on particular 50cm by 70cm baffle and speaker. Bass and treble response should be balanced on any speaker as we know from Olson's RCA research on the influence on bandwidth to a natural sound. For example if a speaker reproduces from 100Hz up it will sound shriil if it goes up to 20kHz. After all 40Hz is ones octave above 20Hz, 10KHz is one octave below 20kHz. Currentlty on Pleiades lab comparisons are done by ear-brain speaker vs reference Sennheiser hd-580 headphones at same loudness. There was not much bass with Tesla 5in speaker although the mid quality was good. There was some bass with the Fostex speaker. there was much more beautifull and deep bass with the Grundig 5"x10'fullrange speaker. Mid high heaviness was reduced by adding a sereis inductor of 1.7mH see next posts. How would baffles created from 2 or 3 linoleum boards glued together would sound like? How would a say Puioneer CS-353 size box made from such thickness linoleum panels sound like with the great Fostex 4.5'FE-127E connected in series with a 1.7mH inductor and 40 ohms in parallel with such inductorm (see next posts) sound like? The idea is to use the sound absorption (damping) properties of linoleum while creating something colored and beautiful. 45 degrees panels may be cut very carefully with the Olfa 45 degrees cutter, not tried yet.