Why does sometimes bass not sound effective when both speakers are connected to a stereo amplifier and whereas the punch is obtained on disconnection of any one speaker?

There are a few reasons why bass might not sound effective when both speakers are connected to a stereo amplifier, but can improve when one speaker is disconnected.

- Phase cancellation:

- When two speakers are playing the same signal, the sound waves from each speaker interact with each other.

- At some frequencies, the waves can interfere with each other, causing a reduction in the overall sound level.

- Speaker placement:

- The placement of the speakers can also affect the bass response. If the speakers are too close together, the sound waves can interfere with each other, causing a reduction in bass.

- The sound reflecting off the wall could interfere also with that from the speaker hence leading to reduced bass punch. Placing it at some distance apart results in reduced reflections which enhance bass punch.

- Room acoustics:

- The acoustics of the room can also affect the bass response. If the room is too reflective, the sound waves can bounce around the room and interfere with each other, causing a reduction in bass.

- Subwoofer:

- Some stereo amplifiers may benefit from the addition of an external subwoofer for improved bass punch and better overall sound quality.

Disconnecting one speaker can effectively eliminate these issues, resulting in punchier, more pronounced bass. However, this comes at the cost of stereo imaging and may significantly affect the frequency range reproduction if that was done to a woofer in the multi-driver set speaker type.