Need help timbre matching center speaker

[BLUCanadian]

Hello
I have been having a hell of a time finding a Energy C-C100 center channel speaker. Hence, I need help "timbre matching" for a center channel speaker
To be honest I have no idea what timbre matching means so a brief explanation would also be helpful.
I have Energy C-500s for my fronts, Energy C-100 bookshelfs for surrounds

Energy C-500 specs
System Type.........................................Bass Reflex, Rear Vented
Frequency Response...............................35Hz-20kHz +/- 3 dB
Recommended Amplifier Power...................up to 150 watts
Components........................................ ..Chambered 1" Aluminum Dome, Dual 6-1/2" Composite Fiberglas cones
Impedance......................................... ..8 ohms nominal; Minimum Impedance: 4 ohms
Useable Bass Response (-10db Anechoic)...30 Hz
Sensitivity (anechoic).............................91dB
Sensitivity (2 speakers in a typical room)....94dB
Crossover Point .....................................1.2kHz and 2.5kHz
Overall Dimensions..................................W - 8"/20cm
.................................................. ........H - 37.5"/95cm
.................................................. ........D - 14.5"/37cm
Weight............................................ .....44.1lbs / 20kg ea