When sourcing external speakers, you must prioritize Frequency Response (ideally 20Hz-20kHz for full range) and Signal-to-Noise Ratio (SNR); a higher SNR (e.g., >80dB) ensures clearer sound with less background hiss. Additionally, verify the Total Harmonic Distortion (THD), which should be less than 1% to prevent audio degradation at high volumes. For active speakers, ensure the RMS Power (Root Mean Square) is clearly stated rather than just 'Peak Power,' as RMS represents the continuous power handling the speaker can sustain.