[HAL]

Since the dspNexus 2x8 can be used for either new speaker designs or reworking old speaker designs, decided to give it a try with a pair of Magnepan MG10QR planars I found.  Had a pair of Magnepan MGIIB's back in the '80s, so a good place to start.  At 10.5in wide about half the width of my old MGIIB's, so that should improve imaging.  Mechanically time aligned, but adding a servo sub will time align them for the room setup.

These are the original Quasi-Ribbon model of the speaker, a two way crossover design with single pole filters.  The response is reported as 80Hz to 22KHz for the speakers, so a good subwoofer is needed for first octave sound reproduction.  I know how to do that!

Speaker measurements are needed to see what will be the new DSP crossover design.

A few surprises along the way, so will see what happens.

[HAL]

To drive the MG10QR's bass panels, will be using Pizza Box Amp v2.1 with the new 1kW SMPS and capacitor filter.  Those will be tested soon.  The QR tweeter amp will be the Orchard Audio Starkrimson monoblocks with 300W GaN SMPS.

This will be 500W into the planar 4 Ohm load, so should have plenty of dynamics even with the 86dB/1w/1m sensitivity to 113dBSPL.  The QR's should be good to 108dBSPL.
The fuses will remain after the crossover upgrade.

The dspNexus 2x8 DSP crossover design is done for testing. 

Now to mod the speaker crossovers to allow access to the two drivers directly.

[orchardaudio]

Looks like a fun project, have fun.

[HAL]

Leo,
Thanks!  This is fun stuff!

The MG10QR rear panel with the original jumpers connected.

From what I can find in the documentation, the links are places to insert passive components to attenuate the QR tweeter and Low Pass filter the bass planar panel.   Once I have the panel off, will be able to tell the places to see if they can be used to Biamp the speakers.  If not, then rewire the posts with new labels to use instead.

[HAL]

Removed one of the rear panels to see the crossover and connections to the planar woofer and quasi-ribbon drivers on the MG10QR's. 

Using fast-on connectors for driver connections, so easiest connection scheme is to add 4 new 5-way binding posts and new wires with fast-on connectors to the panel connections.  Will keep the fuse connection to the tweeters.

Connectors on order and will wire them with some Belden 14awg wire.

[HAL]

Here is the crossover and connections to the MG10QR drivers.  Just going to disconnect the original crossover and install new wiring to new 5-way binding posts directly to the drivers

[HAL]

As part of the MG10QR testing with the servo subs, have ordered a pair of Magna Risers MK7 adjustable stands.  It is possible that instead of the MK7's might get the new Airborne v2 series depending on availability.  Both are designed to work with subs and lift the panels to be more centered on listening axis. 

[HAL]

The 5-way binding posts arrived today.  Superior Electric BP30 model in red and black.

Test fit the connections and everything looks good. 

Will see if it will all fits in the original crossover cavity.

[HAL]

The MG10QR's connector plate with the new biamp wiring and 5-way binding posts is ready to install on to the speaker.

Now to shrink tube the original connector wiring and then on to speaker #2.

[HAL]

First MG10QR rewiring for biamp use is complete!

Time to rework speaker #2.

[HAL]

The second MG10QR speaker is now modified for biamp wiring and the dspNexus 2x8 DSP crossover.

Waiting on the arrival of a new pair of Orchard Audio Starkrimson monoblocks with GaN SMPS to go with the pair I used at LSAF to biamp the speakers. 

[HAL]

The new pair of Orchard Audio monoblocks have arrived and now time to wire up the MG10/QR's.

Making 2ft speaker cables with Analysis Plus Clear Oval 14 and solid copper spades to the 5-way binding posts on the speakers. 

This will get the speakers to ready for testing the frequency and phase response to design the new DSP crossover.
 

[HAL]

Finished the new 2ft speaker cables from the Starkrimson monoblocks to the MG10/QR drivers. 

Time to get the new space setup with the MG10/QR's. 

Got word today that the Magna Risers are getting close to be finished for the speakers as well.

[HAL]

Have the first step of the room acoustics materials setup to check out after the room drywall, paint and flooring are complete.  Side walls have some absorption and rear wall has more diffusion. Room needs more absorption, but a lot better than the reverb chamber it was.

Installed the Magna Risers on the Magnepan MG10/QR speakers. The screws on this pair were 1/4-20 x 1-1/4" style where normally they are 10-32's. Just had to remove some of the coating from the screw holes on the stands to fit the original screws.

Next is to wire them up to the Orchard Audio GaN Starkrimson Monoblock Class D amps and start making some acoustic measurements.

[HAL]

The modified Magna Risers for the MG10/QR speakers will be here Monday from the tracking.

This will put the planars higher on the top installation points with the stainless steel 1/4-20 bolts for mounting.

More gluing this weekend, so hope to have both 4x8in OB H-Frame stacks done when the new speaker stands arrive and then start setup.

The dspNexus 2x8 has a prototype MG10/QR crossover block diagram to run with the Orchard Audio Starkrimson Mono GaN Class D amps.

[HAL]

The Magnepan MG10/QR speakers are now playing music in biamp mode with the EA dspNexus 2x8 DSP crossover driving the four Orchard Audio Starkrimson Monoblocks. Every planar driver with its own HiRez DAC and monoblock amp.  🙂

Now that the system is running will use REW to make measurements with my calibrated Behringer ECM8000 mic to see what needs some crossover work.

[HAL]

After some in room measurements of the MG10/QR speakers, worked on an EA dspNexus 2x8 DSP crossover system to correct what I see as things needed to be addressed in the frequency response. 

The time gate is 500mSec, so this includes room reflections at the ECM8000 mic.  The mic is at the listening seat on axis.

There is a version of an 80Hz High Pass Filter for use when the 4x8in servo subs are running.  That will be tuned once I have final measurements with the servo subs.

[HAL]

Just received a Beyerdynamic MM1 measurement mic. 

Sent the email to receive the 0deg and 90deg calibration data files to use with REW.  Has a 1/4" electret capsule and extended HF response.