2020 Issue-5
I recently moved into a home that has in-ceiling speakers. I have them connected to an A/V receiver and in one room they work great. In the other room, the sound is very muted. There’s a volume control in that room which I’ve replaced and checked. I’m looking for some kind of amplifier that I can purchase or build that can just increase the volume level on that pair of speakers (there’s a pair leaving the receiver which goes into the volume control and then splits into four speakers). I have checked obvious issues and swapped the A/B pairs just to make sure my receiver hasn’t failed.
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It sounds like your problem is an impedance mismatch in the speaker system. Maximum power transfer occurs when the source impedance (output of your amplifier) matches the load impedance (speaker). The gauge of the speaker cable may contribute to the problem. The smaller the gauge the higher the IR loss in the wire. And NO... Monster Cable is NOT significantly better and definitely NOT worth the extra cost.
A better solution is an additional amplifier for those ‘other room’ speakers... defining another ZONE. That amplifier should be fed by a low level output from your receiver My guess is that the previous homeowner had a system with an amplifier per zone and a low level signal distribution system to feed the amplifiers. This can get a bit complicated in design but may translate into a more versatile system.
Because you swapped the A/B speaker leads and got the same audio results, the culprit might be speaker-impedance mismatch. Check the output impedance of your A/V receiver and of the low-volume speakers. The receiver manual should specify an impedance, which in most cases comes to, 4, 8, or 16 ohms. If not in the manual, check for a label at the outputs.
Also, find the impedance of your speakers in the manufacturer's information or on a speaker label. You want the same impedance at both ends. A mismatch can cause reduced volume and even distortion. If you want to measure impedance, here's a link to a helpful article: https://www.wikihow.com/Measure-Speaker-Impedance. If all else fails, look for an impedance-matching transformer. More information here: https://www.electronics-tutorials.ws/transformer/audio-transformer.html.
