M1 Speaker Project ABC Switch testing

HAL · « **on:** 10 Aug 2024, 04:07 pm »

Converting a pair of commercial 2-way speakers from the original passive crossover to a dspNexus 2x8 Audio Weaver DSP crossover.

Building an RPi5 driven ABC switch to compare the original passive crossover, a passive crossover with better quality components and the DSP crossover. The user can run a Thonny Python 3 program to switch between all three crossovers after level matching at 1KHz. The Python program is running the GPIO logic now to drive relays for the switching.

Plan to take the setup to CAF2024 in room 702 to demo the system so listeners can hear the differences.

HAL · « **Reply #1 on:** 15 Aug 2024, 01:46 am »

Made some heavy felt tweeter rings for the M1 speakers for trials.

Found a non-permanent adhesive to attach them to the baffles for trials.

HAL · « **Reply #2 on:** 19 Aug 2024, 03:24 pm »

One ABC relay setup wired of the four needed for the system.

HAL · « **Reply #3 on:** 27 Aug 2024, 01:55 am »

The ABC relay wiring is complete.

Now to build the logic driver board for the RPi to control the relay switching.

HAL · « **Reply #4 on:** 2 Sep 2024, 09:35 pm »

The M1's with the dspNexus 2x8 DSP crossover running the system as a biamp setup. No subs running at this point, but wired for use as needed.

The AGN II's are waiting on locking connectors to arrive this week to complete the connections to the amps for testing.

HAL · « **Reply #5 on:** 5 Sep 2024, 10:46 pm »

Getting the connection wiring ready for the ABC Switch system relays.

Now to install the connectors in the box for checks.

HAL · « **Reply #6 on:** 11 Sep 2024, 10:54 pm »

Trying out the relay box idea with one box per speaker with the drive electronics remoted.

This way the speaker cables can be short with longer control cables that are relay coil drivers.

HAL · « **Reply #7 on:** 13 Sep 2024, 08:11 pm »

The first ABC Switch relay box #1 prototype is done. The Neutrik connectors are relay switching signals on the front with the outputs to the speaker drivers.

Rear connectors are the ABC inputs from the different crossovers.

Now to build relay box #2.

HAL · « **Reply #8 on:** 14 Sep 2024, 03:01 am »

The ABC Switch relay box #2 prototype is done.

Now to build the logic control box with the SMPS and start testing

HAL · « **Reply #9 on:** 16 Sep 2024, 02:56 am »

Starting to wire the Logic Control Box for the ABC switch and some of the interconnect cables.

HAL · « **Reply #10 on:** 24 Sep 2024, 02:53 am »

The M1 speaker original passive and upgraded passive crossovers with connection cables to be mounted in the box for connection to the ABC Switch box.

HAL · « **Reply #11 on:** 24 Sep 2024, 08:56 pm »

The new passive crossover box with wiring for connection to amps and the ABC Switch.

The bottom pair of 5-way binding posts on the top box are spares.

HAL · « **Reply #12 on:** 26 Sep 2024, 06:22 pm »

The ABC Switching system is taking shape. Some of the boxes are remote at the speakers from the control center that ties to a display and wireless keyboard.

HAL · « **Reply #13 on:** 2 Oct 2024, 01:36 am »

Built the two relay driver pc boards and wired them to the output connections.

Next is to wire the RPi5 GPIO wiring to the driver pc boards.

The time to test the relay switching.

HAL · « **Reply #14 on:** 4 Oct 2024, 08:28 pm »

The ABC Switch RPi5 and Relay control boards are now connected.

Time for some relay testing for channel #1 then swap to channel #2. Then onto both channels.

HAL · « **Reply #15 on:** 6 Oct 2024, 06:04 pm »

The ABC Switch system is operational.

Now to finish wiring the crossovers for the speakers.

HAL · « **Reply #16 on:** 11 Oct 2024, 09:45 pm »

The M1 speakers ABC Switch System is ready for testing.

This is the original passive crossover, upgraded component passive crossover and inputs for the dspNexus 2/8 DSP crossover system.

Now for system connection and listening trials. Need to level match the 3 crossovers. Cable lengths for each channel are 8ft of Belden 1309A 14awg speaker cable without the PVC jacket.

Then, let the games begin! 😮

HAL · « **Reply #17 on:** 12 Oct 2024, 11:06 pm »

For the upgraded M1 speaker crossover, the original value of two inductors used is not a stock value. Had a matched pair of aircore inductors made for the new passive crossover for the ABC Switch box system.

I will install these and ready for system installation and ABC crossover trials.

HAL · « **Reply #18 on:** 13 Oct 2024, 03:00 am »

The M1 speakers ABC switch system is getting installed.

Will finish wiring the setup tomorrow for some listening.

HAL · « **Reply #19 on:** 17 Oct 2024, 02:27 am »

The M1 box speakers ABC Switch is operational.

Starting with the original passive crossover for reference. Will start the Logic Controller tomorrow to try the upgraded component passive crossover.

The nice part is that both passive crossovers are always being run with one amp channel, so both get run time even if not used.