The M1 speaker project with ABC switch

[HAL]

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.

[Nick B]

Rich,

That is a really good idea 👍

Nick

[HAL]

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.   

[HAL]

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]

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.

[HAL]

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]

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.

[HAL]

The ABC Switch system is operational.

Now to finish wiring the passive crossovers for the speakers.

[HAL]

The M1 speakers ABC Switch System is ready for testing.

This is the original passive crossovers, upgraded component passive crossovers 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! 😮

[Nick B]

The M1 speakers ABC Switch System is ready for testing.

This is the original passive crossovers, upgraded component passive crossovers 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]

Getting close Nick!

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]

The M1 speaker ABC Switch is getting installed for testing and listening.

Will be using a new dspNexus 2/8 with AK4499EX DAC's arriving today for the setup for CAF2024.  My other systems are setup and wired, so time for a travel unit.

[Nick B]

The M1 speaker ABC Switch is getting installed for testing and listening.

Will be using a new dspNexus 2/8 with AK4499EX DAC's arriving today for the setup for CAF2024.  My other systems are setup and wired, so time for a travel unit.

Rich,

Can you transport the blue speakers in a van or do you need something bigger?

Nick

[HAL]

Nick,
Yes, the AGN II speakers can go in a large van.  A minivan might work.  I have used an E350 or Transit style to move them. 

These are not going to CAF2024.  The demo room available are to small to set them up.

[Nick B]

Nick,
Yes, the AGN II speakers can go in a large van.  A minivan might work.  I have used an E350 or Transit style to move them. 

These are not going to CAF2024.  The demo room available are to small to set them up.

Ok. Thx Rich