Author Topic: The M1 speaker project with ABC switch  (Read 4752 times)

Online HAL

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The M1 speaker project with ABC switch
« on: September 11, 2024, 04:12:06 PM »
Working on a demo for CAF2024 room 702. 

Had feedback that folks want to hear what the dspNexus 2x8 can do for normal box speakers, so have a plan to retrofit a 2-way speaker I will call the M1 with an ABC Switch to allow the room to hear the difference between the original passive crossover, upgraded passive crossover and the dspNexus 2x8.  This was a production speaker that is an 8in acoustic suspension woofer and sealed tweeter. 

Been working on the switching system to go between the 3 crossovers and using relays with a RPi5 as a controller driving power MOSFET's driving the12VDC  relays.  All the wiring and connectors are the same for all 3 channels. 

The RPi5 control system works, so now to try and house the system for use.  To prototype, just using cardboard boxes big enough to hold the parts. 

There will be one box behind each speaker with a separate control box with keyboard and monitor for switching control.  The Neutrik 4-pole connectors are the drive signals to the replays with protection diodes.

Here are the relay boxes with parts just being test fit before cutting holes and installation.

Offline Nick B

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Re: The M1 speaker project with ABC switch
« Reply #1 on: September 11, 2024, 10:47:09 PM »
Rich,

That is a really good idea 👍

Nick
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Online HAL

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Re: The M1 speaker project with ABC switch
« Reply #2 on: September 12, 2024, 05:23:46 AM »
Nick,
Thanks! 

This should be very revealing of the differences for anyone that has not heard all styles of crossovers on one speaker. 

The upgraded passive parts are also better matched channel to channel compared to the original crossover.   :thumb:

Online HAL

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Re: The M1 speaker project with ABC switch
« Reply #3 on: September 13, 2024, 01:08:20 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.

Online HAL

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Re: The M1 speaker project with ABC switch
« Reply #4 on: September 25, 2024, 08:23:50 AM »
The new passive crossover boxes are nearing completion. 

Once done, just need to build the pc board with the power MOSFET's for the relay control and then wire up the system.

Online HAL

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Re: The M1 speaker project with ABC switch
« Reply #5 on: October 01, 2024, 06:43:42 PM »
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.

Online HAL

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Re: The M1 speaker project with ABC switch
« Reply #6 on: October 04, 2024, 12:25:03 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.


Online HAL

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Re: The M1 speaker project with ABC switch
« Reply #7 on: October 06, 2024, 12:24:47 PM »
The ABC Switch system is operational.

Now to finish wiring the passive crossovers for the speakers.