My passion is JBL speakers and I thought it would be nice if I could instantly compare them at the same volume levels. And wouldn’t it be really cool if there was a way to bring on a speaker at random for comparison to see if you can hear a difference (the X speaker so to speak)?

This is for an A/B/X speaker switcher with the cabability to match levels…, or not. With a set of jumper wires between the A and B outputs, it can also be used a partial and full mute for the system.

I’ve not ever seen any similar units offered for the consumer though I have heard of them being used in the professional world for speaker evaluation.

This uses a 4-channel, 12 volt key fob transmitter/receiver with buttons marked A,B,C, and D ($9 from China including two key fobs)

Pressing A or B (set to momentaneous) instantly brings on speaker A or B.

Pressing C (i.e., “speaker X”) (set to momentaneous) makes the unit go mute until released. When released either speaker A or B will come on at random. An LED on the panel indicates which set is playing.

Pressing D (set to interlocking) mutes the system and pressing it again brings it back on.

When “mute”, the amp is routed to two 100 watt 8-ohm resistors to avoid damage to the output stages.

The audio signal L-pads are stereo 100 watt. The 4PDT switches by-pass the L-pads while still allowing all switching capabilities. I’m using USA-made Eaton 15 amp 250 volt switches with silver contacts. The audio relays are rated for 40 amps with silver contacts. When done, (I’ve started to receive parts), this could be available for So Cal members use in demos.