Another shot of the Line Array box before painting.
SL3-eXtreme Center channel speaker – a design and build story
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Painted Box
And here it is in its glorious flat black.
Again, it sits behind a screen with microperfs, which let about 10% of the light through, so nothing shiny or reflective is allowed back there
And here it is in its glorious flat black.
Again, it sits behind a screen with microperfs, which let about 10% of the light through, so nothing shiny or reflective is allowed back there
Mounting Board
Now we need to mount the painted Line Array box and the ESL frame to a mounting board.
Since the Infinite Baffle is 23x23” and the sum of the widths of the SL3 and the new LA box is precisely 23”, we make our mounting plate 23” x 20”
This will allow the units to be screwed in from the bottom of the mounting plate, then the mounting plate itself will be screwed onto the IB box. It will not be going anywhere. This will be the most solidly mounted Center I’ve yet to see
This shot shows the ESL frame and the LA Box screwed into the plate, which in this pic is upside down so we can actually put the screws in.
Now we need to mount the painted Line Array box and the ESL frame to a mounting board.
Since the Infinite Baffle is 23x23” and the sum of the widths of the SL3 and the new LA box is precisely 23”, we make our mounting plate 23” x 20”
This will allow the units to be screwed in from the bottom of the mounting plate, then the mounting plate itself will be screwed onto the IB box. It will not be going anywhere. This will be the most solidly mounted Center I’ve yet to see
This shot shows the ESL frame and the LA Box screwed into the plate, which in this pic is upside down so we can actually put the screws in.
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Plate Bottom
Here you can see the bottom of the plate with the screw patterns to hold the units. The screw holes are counter-sunk so that the plate will sit flat on the IB surface.
Next step is to take the naked (but now drilled out for the new units) mounting plate and get the correct screw pattern to put into the IB.
Once that’s done, I’ll route edges and paint.
Here you can see the bottom of the plate with the screw patterns to hold the units. The screw holes are counter-sunk so that the plate will sit flat on the IB surface.
Next step is to take the naked (but now drilled out for the new units) mounting plate and get the correct screw pattern to put into the IB.
Once that’s done, I’ll route edges and paint.
Wiring up the Woofers
To achieve a reasonable load on the amp with six 7 to 8 Ohm speakers, you need to wire them up so that they produce a load somewhere in the range of 4 to 16 Ohms.
Therefore, we will combine series and parallel wiring techniques to achieve our goal.
Use two series wired sets of three speakers each. Each set is paralleled into the amp for a total load of around 11 Ohms.
Here is the diagram of the parallel sum of the two sets
To achieve a reasonable load on the amp with six 7 to 8 Ohm speakers, you need to wire them up so that they produce a load somewhere in the range of 4 to 16 Ohms.
Therefore, we will combine series and parallel wiring techniques to achieve our goal.
Use two series wired sets of three speakers each. Each set is paralleled into the amp for a total load of around 11 Ohms.
Here is the diagram of the parallel sum of the two sets
Set of series wired drivers
And here is the one with the series set layout, this is done for each set of three speakers:
Since the Extremis is rated at 100w for each driver, running them at 1/3 rated handling is relatively safe. We could even double the power and still be well within the design limits.
The wiring will be done so that each series set will go to its own binding post cup. The parallel wiring will happen with the feed connectors.
This gives us the option of wiring it up with two channels of amplification (albeit, with much higher impedance).
And here is the one with the series set layout, this is done for each set of three speakers:
Since the Extremis is rated at 100w for each driver, running them at 1/3 rated handling is relatively safe. We could even double the power and still be well within the design limits.
The wiring will be done so that each series set will go to its own binding post cup. The parallel wiring will happen with the feed connectors.
This gives us the option of wiring it up with two channels of amplification (albeit, with much higher impedance).
Wiring Diagram
And here is the guide I made to help me build the wiring loom.
I use a high-quality OFC, silver-clad wire along with gold-plated crimp-on spades.
And here is the guide I made to help me build the wiring loom.
I use a high-quality OFC, silver-clad wire along with gold-plated crimp-on spades.
Driver assembly
Here is a shot of the drivers all lined up on the box and wired up. The mounting holes have been drilled out, and the box stuffed to 100%.
Here is a shot of the drivers all lined up on the box and wired up. The mounting holes have been drilled out, and the box stuffed to 100%.
Testing
Before I mount the Line Array and the SL3 to the mounting base, I first need to run some tests and measurements.
Each unit is hooked up to an amp channel fed directly by my ETF measurement system. The mic is left at exactly the same point throughout this entire test to ensure comparisons are equal.
Here is the SL3 element alone being tested.
Before I mount the Line Array and the SL3 to the mounting base, I first need to run some tests and measurements.
Each unit is hooked up to an amp channel fed directly by my ETF measurement system. The mic is left at exactly the same point throughout this entire test to ensure comparisons are equal.
Here is the SL3 element alone being tested.
Frequency responses
Here is the measurement of the SL3 ESL panel alone. The dark blue and dark green traces are with the 1 Ohm resistance in-line. The cyan trace is the response with the re-configured switch bypassing the 1 Ohm load. As you can see, better high-end response, but a nastier load on the amp. Not that it’s a problem for the Sunfire.
Also, this FR is way smoother than the Logos. Guess a new Panel and an active X-over help
Here is the measurement of the SL3 ESL panel alone. The dark blue and dark green traces are with the 1 Ohm resistance in-line. The cyan trace is the response with the re-configured switch bypassing the 1 Ohm load. As you can see, better high-end response, but a nastier load on the amp. Not that it’s a problem for the Sunfire.
Also, this FR is way smoother than the Logos. Guess a new Panel and an active X-over help
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Mid-Bass Line Array frequency response
Here is the measurement of the Line Array at 2 meters. It l looks really smooth way past crossover points along with a good low-end extension.
The Extremis driver is often used as a woofer in other designs, so it does really well here.
With the power handling of six drivers and the throw characteristics of a line array, this should mate very well with the ESL.
Here is the measurement of the Line Array at 2 meters. It l looks really smooth way past crossover points along with a good low-end extension.
The Extremis driver is often used as a woofer in other designs, so it does really well here.
With the power handling of six drivers and the throw characteristics of a line array, this should mate very well with the ESL.
Mounting
Now that the testing is over, time to put both units together on the mounting board that is now routed, sanded, and painted. It was pre-drilled for the IB locations and screw-holes countersunk.
Here is a shot of the units being screwed in. Of course, it’s all upside down for now.
Now that the testing is over, time to put both units together on the mounting board that is now routed, sanded, and painted. It was pre-drilled for the IB locations and screw-holes countersunk.
Here is a shot of the units being screwed in. Of course, it’s all upside down for now.
Inserting ESL Drive board
With the units screwed to the mounting plate and the plate screwed to the Infinite Baffle, we are now ready to wire this puppy up.
First, we take our re-engineered ESL drive and backing plate and hook up the ESL panel wires. Then slide the drive board into the slot under the SL3. Looks factory stock once it’s all in.
With the units screwed to the mounting plate and the plate screwed to the Infinite Baffle, we are now ready to wire this puppy up.
First, we take our re-engineered ESL drive and backing plate and hook up the ESL panel wires. Then slide the drive board into the slot under the SL3. Looks factory stock once it’s all in.
Done!
All the wires hooked up, the new DriveRack 260 cabled in, and a baseline config was thrown in (using parameters outlined in the first few posts); she’s ready for some music!
And some glory shots, so here come a few.
First, a three-quarters view showing the new SL3XC mounted onto the Infinite Baffle. You can see the Monoliths and my equipment room rack on the left.
All the wires hooked up, the new DriveRack 260 cabled in, and a baseline config was thrown in (using parameters outlined in the first few posts); she’s ready for some music!
And some glory shots, so here come a few.
First, a three-quarters view showing the new SL3XC mounted onto the Infinite Baffle. You can see the Monoliths and my equipment room rack on the left.
A full frontal view
From above
Time for some measurements
Now that glory shots are done, time for some measurements.
BTW- the strip of lighter stuff on the bottom of the ESL panel will be masked out with black felt later. I was in a rush to hear the sucker
I'll post back later with measurements and listening impressions.
But here’s a preview: I played over an hour of music last night as soon as it was running, and I was very, very happy. Can’t wait to tune it, so I’m off to do that now.
Now that glory shots are done, time for some measurements.
BTW- the strip of lighter stuff on the bottom of the ESL panel will be masked out with black felt later. I was in a rush to hear the sucker
I'll post back later with measurements and listening impressions.
But here’s a preview: I played over an hour of music last night as soon as it was running, and I was very, very happy. Can’t wait to tune it, so I’m off to do that now.
raphant69
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Hi Jonathan,
great job you've done here!
I was wondering about the stator on your SL3 panel. It seems to have the transparent "clear spares" on the last photo. Does that mean that new replacement panels benefit of these new spacers?
I'm waiting for new ones for my Sequel II's and don't know if I'll have the old black spacers or new the transparent ones.
Once more, congratulations for your project.
Raphaël.
great job you've done here!
I was wondering about the stator on your SL3 panel. It seems to have the transparent "clear spares" on the last photo. Does that mean that new replacement panels benefit of these new spacers?
I'm waiting for new ones for my Sequel II's and don't know if I'll have the old black spacers or new the transparent ones.
Once more, congratulations for your project.
Raphaël.
raphant69 said:
Yep, that's a clearspar ESL panel.
Seems the SL3 /Sequel panels are now coming that way.
However, my new Monolith panels are NOT clearspar. I'm bumming about that, as the SL3XC will be behind the screen, but the Monoliths are visible (duh!, they're huge) I'd have rather had clear on those panels. Oh well.
The measurement difference between old and new panels is significant. I'll document later. Don't wait, order new panels for those Sequel's.
Oh, and thanks. This has been waaay more work than I bargained for. My plans to also do woofers and panels on the Monoliths had to take a back seat to this challenge.
But it’s been worth it, very much so. As I sit here listening to the Sting ‘Sacred Love’ album in SACD, my jaw keeps hitting the keyboard …
Drum dynamics like I’ve never heard in my rig. The vocals (which are almost 100% anchored in the center channel) are now razor sharp, and they are the same volume as the L/R at ‘high’ (avg 90db) volumes.
Tweaking the DriveRacks for phase and levels has the bass even tighter than ever, that big Infinite Baffle is the bomb as well. It keeps up with the Martin Logans like nothing I’ve ever heard. Tight, accurate and ‘infinite’ in depth
It’s hard to believe it will soon get even better with the new Monolith Panels and the woofer change
