Here are some of the key risks of connecting a 4-ohm speaker to an 8-ohm amplifier:
- Overheating and damage to the amplifier – The lower impedance of the 4-ohm speaker draws more current from the amplifier. This extra current can overheat and eventually damage the amp if it lacks sufficient current delivery capabilities.
- Distortion at high volumes – Even if the amp can handle the current, it may start clipping or distorting at high listening volumes when trying to deliver more power into the 4-ohm load.
- Impedance dips – Speakers have variable impedance over frequency. Impedance dips below 4 ohms can further stress the amplifier.
- Lack of headroom – With less headroom, the amp is more likely to clip and distort at high volumes when driving 4-ohm speakers.
- Louder is not better – Just because a 4-ohm speaker may play louder with a given amp, it doesn’t mean the sound quality will be better. Distortion often increases.
- Damage over time – Even if no immediate problems arise, the extra stress on the amp over time may lead to premature failure.
- Voided warranty – Driving 4-ohm speakers may violate the terms of the amp’s warranty and void coverage.
- Safety hazards – Significant overheating could potentially lead to fire risks in extreme cases.
The bottom line is it’s best to match the speaker impedance to the amplifier’s rating. While some amps can handle 4-ohm loads, it’s generally not worth the risks involved. When in doubt, check with the manufacturer.
Citations:
[1] https://electronics.stackexchange.com/questions/374901/what-is-the-danger-in-plugging-an-4-ohm-speaker-into-an-8-ohm-amplifier
[2] https://audiokarma.org/forums/index.php
[3] https://www.audioholics.com/frequent-questions/connecting-4-ohm-speakers-to-an-8-ohm-receiver-or-amplifier
[4] https://arendalsound.com/guide/4-ohm-speakers-with-8-ohm-amplifier/
[5] https://www.thegearpage.net/board/index.php
[6] https://www.ooberpad.com/blogs/audio-video-tips/loudspeakers-at-4-ohms-vs-8-ohms-what-s-the-difference-and-why-it-matters