Isiris evolution to Osiris Jr? Summary of Isiris build and new update

[Matt M]

What a beautiful girl! Somehow the words "pulling through" come to mind. Don't know where that comes from...

[meb46]

It's been pretty slow going over the past few weeks on the audio front, but in between a new baby, work frustrations and travel, I have managed to make some progress on the Speakers and overall system.

With respect to the Speakers, Jon and I have managed to work out a solution for testing my speakers and getting data for the crossover design, despite the 13,500+ kilometer difference in locations of the two of us. We have the assistance of a very helpful thirdparty here in Singapore, and now its just a case of getting the room setup for measurements and some time in a quiet house.

After some initial tests, we have decided to add into the mix, some large Acoustic Absorbers, and also the need to move the speakers into a more optimal spot. End result will be some big acoustic absorbers sitting to each side of the test speaker, and then another suspended above it to avoid ceiling reflections. This ultimately means I have had to go back to the workshop to create suitable Absorbers. Mission nearly accomplished, I have two absorbers complete, and the third and fourth will be complete before the weekend is over.

Absorbers:

I have ended up creating an MDF Frame about 2.4 x 1.2m, which then gives me a layered solution as follows - 25mm Air gap from the wall surface, then 60mm of an Acoustic Rockwool slab, then finally the <150mm fingered Acoustic Foam. The stack up is then framed win the white MDF Frame and hung on the wall... see picture below. All seems to work well, and has transformed the sound of the solution already... and thats with in correct cross overs. I have built two of them so far, and just need to stick in the Acoustic Foam on the last two.

System Changes:

I recently ditched my Rotel RB-1092 in favour of my own custom Hypex NC502MP Amplifier - see photo. I much prefer the Hypex sound, and have subsequently spent a lot of time in the recent weeks listening to Amplifiers as a general comparison, to hopefully decide on which direction to head in, or still with my NC502MP unit. Thus far, I have listened to: Plinius SB-301, Krell 600c, Bel Canto REF500M, and NAD M22. At this stage, I actually like the NAD M22 and Plinius best... but wont make a decision until I have hear the NAD M22 V2, currently not yet available in Singapore. What did happen, is that I got all very immersed in the NAD M12 PreAmp/DAC/Streamer, and ended up buying one. Also see picture below. Really happy with the units, and will work well with an NAD M22 V2 if I head in that direction... what I like the most on the M22 V2 is the switchable mono-block configuration for some real ridiculous power...

Next Steps:

As soon as I have the next two Acoustic Absorbers, I will be moving the Test Speaker to the centre of the room, and then arranging the Absorbers to create a faux anechoic chamber, and then working up a system for 0/15/30/45 degree measurements for each driver. Finally some progress

Current Setup including Left Speaker, Acoustic Absorber, M12 and NC502MP Amplifier.

[fish fingers]

I just love the cab colour on those.
We have a good NAD dealer in Bangkok called Conice, I was looking into a similar set up. Back in London atm and ordered a pair of Cell C90's to take back.

[cochinada]

That DIY accoustic absorber looks very professional but from the picture I would never guessed it is so deep like you wrote. About 235mm?

[meb46]

Cochinada - The tips of the Foam Fingers extend well forward of the actual Frame. The Frame is 150mm deep, then the fram to tip of Foam is another ~85mm. I guess the angle of the photo makes this look a lot less deep...

[meb46]

Finally - Speaker Testing day has arrived and now completed. Setup of Sound Absorbers shown in pictures below. We also added some treatments to the floor and the door behind the speakers to help cut down some of the reflections.

The Cabinets are a little heavy to rotate, so had to rotate the Microphone instead. All drivers had measurements taken at 0,15, 30, 45, and Nearfield. Speacial thanks to my Singaporean Measurement Ninja for his assistance - very much appreciated, and simply not possible without him!

[cochinada]

Great stuff and those sound absorbers are scary big! I totally understand how difficult would be to turn those monsters but even so I almost hear Kimmo saying as he did to me: you need to measure at least up to 140 or so degrees for an accurate power response. 45º is simply not enough I'm afraid.

[5th element]

Those are ridiculously big speakers...

[Dave Bullet]

What a great read from start to "so far" this thread has been. How are things going? I realise such ventures are a journey, and your partner in crime being on the other side of the world adds to the recipe.

[Evil Twin]

The setup and promise of the tests in Singapore were not realized adequately for extracting the necessary design files.

New test enclosures for specific drivers are almost complete- this weekend I will be routing the front panel and prepping an enclosure for the AS250...





I obtained another C168 midrange, and have SS 7140's on hand, and am pondering two enclosure concept for testing- one baffle width correct, the other a complete replication of the front panel design. To accomplish that, of course, a new power tool is required and ordered, and is expected to be delivered on Saturday.

More details will not be shared at time, lest they fall into rebel scum hands.

[Evil Twin]

Matters are moving forward as expected and desired, at long last.

The first step is completing some work on the low frequency test cabinet for the AS250.

This 48L test enclosure will additionally utilize a passive radiator to test the concepts for a three way system without the dual 15" woofers. Modeling shows that with the optimum passive radiator mass tuning, 3 RSS265PR could be used, in a larger enclosure, but as we are not desiring to build a new range of outsized monkey coffins, this test cabinet has a more optimized baffle width and just one passive radiator. Several concept configurations have been modeled, but for now only one 48L configuration will be constructed and tested.


Having a router with good dust collection is essential when one's wardrobe is all black...





For mounting the RSS265PR on the rear baffle on a test enclosure, flush rebate mounting is unnecessary- a simple precision pass through hole will do.





The mounting configuration was double checked- The Emperor we must trust, all others we verify...




The clearance tolerance is satisfactory, at about 1mm.


Of course, the AS250 requires a more complex rebate and hole...





And the dimensions were chosen so that the driver can be readily lifted from the mounting rebate- something not as easy to do in practice as one might think, given it's 14 kg mass.

[Evil Twin]

Next steps

The next phase of construction prior to testing is well underway, with a possible boost thanks to a tool suggestion by Mr. Manning...


For the midrange and tweeter, it is critical to have a matching baffle test setup for the C168 and SS7140 comparable to the already built cabinets.

This requirement is being fulfilled now... the test front panel has been ready for some time...




And now it remains to build a cabinet around it.





This construction target is not simple... lacking for the most part parallel planes...








Mr. Manning recommended a Bosch GCM12SD dual bevel saw with a most unusual arm mechanism, rather similar to one of the local landspeeders I have added to my collection...




THIS should provide the accuracy and control which I seek...





A cursory inspection of the mechanism and available adjustments indicates that it should meet my requirements, with the addition of a suitable Forrest Chopmaster blade and an OSHLUN laser sighting guide.

[ergo]

I can concur with the recommendation. Got same model of Bosch mid summer. I've yet to get around as nice and elaborate speaker box project with it, but the more common construction site stuff as well as interior moldings were a breeze.

Btw - what size is the center hole of the blade for this model in US. In Europe it is 30mm... I was just trying to look if it perhaps would make sense to hunt a better blade for my saw from US, as I'm going week after next. But bulk of the miter saw blades in US seem to have 1/2 inch hole or at least much smaller than the 30mm.

[Evil Twin]

This US version uses a 25.4" arbor hole, and that is pretty much standard unless you get into something off the beaten track like a Festool Kapex, with a 30mm European (I presume) arbor. 10" saws usually use a 5/8" arbor.

Besides quality of assembly and the quality and mount of the carbide teeth, the other factor that seems important for dense materials like oak or maple ply, is having either a 0 degree hook angle (like my DeWalt Laminate blade) or even a -5 degree hook angle (like this highly regarded Forrest Chopmaster blade). The negative angle is common to non-ferrous metal and plastics blades, but not so much for wood. I would say a slower cut, but when you have 96-100 teeth, I doubt that's the case.

I do not think there is any denying that when you can get cuts this smooth without sanding in 3" of hard maple ply, it is a strong technology approach...





Just for your amusement, I will send directly to you the non-reduced size undoctored image of this cut...

That DeWalt blade is difficult to find these days. Hence, researching and trying the Forrest.

[Dave Bullet]

Dark Lord, the resemblance is striking. I am sure the Emperor has forseen this.

[Evil Twin]

Clearly the Force is strong with you... your intuition and graphic skills reveal this clearly!

Fabrication should continue this weekend, in spite of such distractions as the arrival of the PuriFi drivers, and a new waveguide + tweeter concept to test which "appears" most promising... pray it does not fail my expectations.

[Renron]

My Master,
I will personally vouch for the validity of the razor sharp (When new) Forrest Chopmaster blades. Merely brushing against the teeth from a side glancing blow has on more than one occasion drawn blood. Not as expensive as a new Land Speeder, but more than a used droid certainly. I have had mine sharpened twice now, it's > 15 years old and cuts like a Light Sabre.
May it please you well.
Ron

[Evil Twin]

My Master,
I will personally vouch for the validity of the razor sharp (When new) Forrest Chopmaster blades. Merely brushing against the teeth from a side glancing blow has on more than one occasion drawn blood. Not as expensive as a new Land Speeder, but more than a used droid certainly. I have had mine sharpened twice now, it's > 15 years old and cuts like a Light Sabre.
May it please you well.
Ron

Interesting... most interesting!

Your judgement and experience in this matter carries far more weight than most...

I am looking forward to first hand experience, after doing extensive research in making this selection...

[Evil Twin]

Nothing else compares...

My Master,
I will personally vouch for the validity of the razor sharp (When new) Forrest Chopmaster blades. Merely brushing against the teeth from a side glancing blow has on more than one occasion drawn blood. Not as expensive as a new Land Speeder, but more than a used droid certainly. I have had mine sharpened twice now, it's > 15 years old and cuts like a Light Sabre.
May it please you well.
Ron

Your comments and praise are now revealed to me for the strong understatements that they are...

A photograph cannot reveal the truth, but only hint at it...




This saw and blade are producing cuts which feel like a skilled craftsman as followed up on the cut with a fine polishing using 800 grit material on a granite machinist stone surface... that flat, that smooth...

The Force is very, VERY strong in this combination of tools!

[JonMarsh]

The Dark Lord is tied up with an Imperial expansion in the outer rim, with property negotiations and starting up a new Death Star.

So for now I'm stepping in, and will complete the test cabinet assemblies, and start testing fairly soon, I expect. The low frequency test cabinet has been completed and additional driver resources procured. Finishingi the midrange cabinet drawings and construction is next up on the task list- I have been warned not to fail him, let my fate be similar to Captain Needa's...

[Renron]

Whew!

I'm relieved that blade meets with your approval, my LORD. I would never want you to be displeased.
I have just removed my favorite Table Saw blade the Forrest Wood Worker II and it's being sent off to reclaim it's authority over the Rebel Scum wood I've been using lately. A new slide saw bench was built so I may serve better.
Humbly,
Ron

Your comments and praise are now revealed to me for the strong understatements that they are...

A photograph cannot reveal the truth, but only hint at it...


[ATTACH=CONFIG]30045[/ATTACH]

This saw and blade are producing cuts which feel like a skilled craftsman as followed up on the cut with a fine polishing using 800 grit material on a granite machinist stone surface... that flat, that smooth...

The Force is very, VERY strong in this combination of tools!

[Evil Twin]

I'm relieved that blade meets with your approval, my LORD. I would never want you to be displeased.
I have just removed my favorite Table Saw blade the Forrest Wood Worker II and it's being sent off to reclaim it's authority over the Rebel Scum wood I've been using lately. A new slide saw bench was built so I may serve better.
Humbly,
Ron

Interesting... most interesting! I suspect that your plans to improve the "authority" of your Forrest Wood Worker II likely correlates with the start of some kind of new project, not necessarily audio related. But construction is constructive...


In my own, the ongoing relocation to the outer rim is reaching some key milestones.

The plans for a compact DeathStar have been completed, much smaller, but very deadly, and will be tucked away in a small out of the way system in the Outer Rim where prying Rebel spies are unlikely to find it. It has a particular focus on the vehicle bays, with a dedicated bay for the Tie Fighter and special service and customization capabilities, dual bays for Imperial shuttles, and a 4th bay dedicated to engineering development, especially for acoustic products and other custom hardware.

Achieving all this with an advanced timeline under current conditions has required creative approaches, including forging alliances with remnants of the Russian diaspora from Old Earth, formerly just a discredited legend of the past. The Force can lead one in unexpected directions...

When complete, it will be possible to explore and develop the more advanced projects conceived two years ago and put aside for future effort.

[JonMarsh]

Modeling of AS250 with SL26R

This is the final review of the test cabinet acoustical details for the AS250 mid woofer with Seas SL26R, in the test build cabinet and an option for a more optimized future build.

The 50L net test build appears to be able to deliver adequate performance for the crossover system integration evaluation.

This is the modeled design using an SL26R with no weights added- just as well, there are no additional weights provided, and the size of the attachment screw is not exactly overwhelming.






The calculated SPL response with 20W of drive:





The resulting excursion:





And the calculated impedance profile:






This is not the configuration for the AS250, but it shows what can be done even with just a single good quality PR and a not so large box. With an F3 of 36Hz, it should be fairly adequate for basic listening tests, also.

[JonMarsh]

Going a bit larger...

Now if one was serious about pursuing this concept, without spending a small fortune in additional drivers, the addition of another PR and expanding the cabinet a bit can deliver some benefits.

Here is the modified design configuration, expanding the cabinet to 65L, and adding a 2nd SL26R.




The resulting calculated SPL response is seen here:




This follows a fairly optimum maximally flat curve, with an F3 of 29Hz. Those 32 Hz low organ notes should be in good shape.


And the calculated excursion profile:





Is reasonably under control, considering what we're asking a single 10" nominal driver to do.

Let's remember now, this is a true 8 ohm driver, not a six ohm DCR part masquerading as an 8 ohm driver.



As a result, a properly designed system impedance with these paralleled is not going to be exceptionally brutal to drive.



A pair of these in a system would certainly be entertaining in a moderate size room. Of course, if wretched excess is your thing, then imagine a 150L cabinet, like the bass cabinet Michael used for his Isirs, with two AS250 and 3 or 4 SL26R.

If the AS250 has the pitch definition and transient behavior of the AS168, that could be very interesting indeed!

[JonMarsh]

And for the thrifty, consider how the RSS265PR with one disk is calculated to perform:

[Bear]

I always wished that SEAS would publish parametric data for their PRs rather than the iso curves. Wavecor and PE do a nice job (mostly) with what they publish. (Wavecor is a touch hit-or-miss, though)

[JonMarsh]

Setting up for fabricating the midrange-tweeter test cabinet finally- putting a second car out in the elements. One must have priorities...


The cabinet will have the same front baffle shape as MEB's build, but as it will not include the extra volume space used for the AS250, it will be shorter overall, similar to to my version of the Isiris build.





I'm in the process of figuring out all the cuts piece dimensioning, and also whether I need to modify the baffle cutout based on Accuton's most recent recommendations for the C168-6-990 and C168-6-890.

[JonMarsh]

Which returns me to my additional direction on this-

though the primary cause for the effort is getting data for developing passive or active crossovers for MEB's 4 way system for the upper three sections, and doing a first pass on the passive versions, I'm looking at another possible effort-

A three way system based on the AS250 woofer plus PR as described earlier in this thread, and possibly using the C168-6-890, which I have on hand. That newer part has a 5 mm Xmax, and some design upgrades, compared to the midrange oriented C168-6-990.

The 990 has a voice coil connected to the edge with a very short throw to minimize the former mass...




And an infinite baffle response that sort of "humps" in the midrange before even considering baffle step- sensitivity is high, but there will be some additional tilt in the response due to baffle step, as my own measurements in a more conventional enclosure confirm.




The C168-6-890 is something of a different creature, with a higher Xmax, lower sensitivity, a longer voice coil and further "innovations" to the mechanical drive configuration.





It's a new part, and I only acquired a pair this year and haven't had an opportunity to test them yet- but I intend to do so in this test enclosure under construction after I get the data for MEB.





Neither are simple to mount with a good acoustic outcome.

[JonMarsh]

And some reminders of C168-6-990 measurements in a 10" wide bookshelf style cabinet:


A polar measurement:




HD2 and HD3 distortion measurement, expressed in dB:





And, yes, this is something of a head scratcher to me, as HD3 is coming in higher than HD2.

[Bear]

HD2 and HD3 distortion measurement, expressed in dB:


[ATTACH=CONFIG]31573[/ATTACH]


And, yes, this is something of a head scratcher to me, as HD3 is coming in higher than HD2.

I find it very hard to look at that and not think about the price tag.

[JonMarsh]

I find it very hard to look at that and not think about the price tag.

No kidding.

I should be cutting BB ply for the test cabinet once we get back from CA. I should dig my C168-6-890 out of storage, too..,,.

[meb46]

Finally... after an eternity from the forum, I am back balancing race car building and getting my last speaker project back on course.

After numerous weekends with my Singapore based Speaker Testing Ninja, I am excited about how things sound!

Finally, I can listen for sequential hours without tiring and we continue to perfect. Exciting times.

Current set up is as follows...

1. Tweeters - March Audio PS252
2. Mid - NAD M22 V2
3. Woofer - March Audio PS502
4. Subwoofer - DS8.0

Active DSP through MiniDSP.

Work in progress... but making leaps and bounds in the right direction

[meb46]

Jon - I owe you an update on where we go to DSP/Active wise... it’s been really positive, so keen to get you up to speed! Email heading your way soon!

[JonMarsh]

that sounds great!

I’ve finally got a couple of saws setup at the new rental, and have started cutting pieces to finish the test cabinet.

Do you have some measurement gear now?

[JonMarsh]

Oh the weather outside is frightful...

Well, to borrow a line from one of those Christmas songs you've probably heard too much of the last few weeks, "Oh, the weather outside is frightful"

But that means the "weather" inside the garage with all the power tools is not very nice, either! And so it has been for a while!

In fact, an article I read online this morning at 9AM when the outside temperature was 0 degrees reported that this was the worst cold snap in 5 years in the Boise area... I know it wasn't anything like this last winter.

But hey, we should have a heat wave coming this week, and it should be 40 degrees warmer in a few days!

So I should be getting back to finishing the cutting board platform for the DeWalt DWS780 and get down to some more business.


Now, today, while I was spending time on organizing some things and getting ready for that hoped for burst of activity, I made a surprising discovery... getting all the bits together for setting up one set of drivers and cabinet to measure has been a somewhat catch as catch can affair, with all the other things going on the last two years. What I discovered that surprised (no, shocked me!) was that I have not one Accuton AS250, but two... yes, two. Hmmm.

And some of you may recall that I do also have two of the C168-6-890. Which is not really just a midrange, but a mid woofer...

This might open up some possibilities for an idea that has lurked in the back of my mind for some time- to make a more compact system, with just the AS250 in an enclosure with PRs, and an upper range setup based on some form of C168. That just might be doable.

I actually unpacked both AS250 boxes, thinking that maybe I was kidding myself and something else was packed in what I thought was an AS250 box. But no, that's not the case. Both are AS250s. And I recall what I purchased them for a few years ago. I thought I would check on the current price before quoting the older one, and I was truly shocked to discover that the current MSRP at Madisound is $1,645.00. YOWZA!! And they are special order, 45-60 days for delivery.

Is this what we call supply chain problems? Inflation?

So, in a spirit of rebellion at this state of affairs, I'm going to post a little bit of speaker porn for you, in case any of you are curious what a $1,645 driver actually looks like up close and personal.... because when you open the box, they are startling- especially the magnet assembly.











Those of you have followed the Kurosawa development or the Ardent D are aware that the Cell drivers have some unusual characteristics, including wide polar response over an extended frequency range compared with conventional cones, and also appear to be engineered with baffle step compensation built into the intrinsic amplitude response profile. I've seen this with both the AS168 and the AS190. It remains to be seen how the AS250 behaves, but I'll hopefully have a good idea soon.

[JonMarsh]

Jon - I owe you an update on where we go to DSP/Active wise... it’s been really positive, so keen to get you up to speed! Email heading your way soon!

I've been kind of swamped on some personal fronts, but I'm going to comb through the emails tomorrow in case you've sent this and I missed it.

[tktran]

Drool. I'd consider these Unobtanium unless outstanding 3rd party measurements...

There's something doing on in speaker components. Everything has doubled in price.
Have you looked at SEAS Excel drivers recently?
Dayton Audio is also double in priced, but you know, from 40 to 80 is a easier pill to swallow.

My SEAS Millennium T25CF002 needed a repair. The great thing about this tweeter is that it will probably be available to the end of time. The voice coil replacement is $50, but a complete new tweeter is now US$350.

I can buy 2 good 12" woofers for this price... so... well I did!

[JonMarsh]

Hey, I've got a vintage new pair of those squirreled away somewhere, except I do remember mating one of them with a waveguide, in consideration of the front plate chamfer? Didn't work anywhere near as well as I hoped.

These suckers will play low and loud, but the pair I had did not have particularly smooth frequency response, no matter how I mounted them, and the value proposition is certainly questionable these days!

I've seen news articles indicating that there is some bonafide fundamental cost increases, but that there is also corporate efforts to increase profits- which accounts for the bigger part of the price increases. Not nice!

I paid less for the two AS250's I have than one goes for now at Madisound. It does model interestingly in Unibox, so we'll see just how well it actually works and what it sounds like in the real world.

My real world experience with the C168 has renewed the interest in completing the Kurosawa project, as the LF alignment is very similar, and the Ardent D with PR's has a pretty remarkable low end. These will probably become my HT speakers and mid fi entertainment center specials after the move, if I can afford a NAD M33 or Cambridge Edge NQ some day.

I've got a lot of saved up deferred gratification to deal with some time.

[JonMarsh]

As50 + slr26r

Well, the weather outside is still frightful, but I've been getting the details on the AS250 cab reviewed and figured it might be fun to share...

Since this is primarily a test project for Michael Bell's Osiris project, you can't blame me for trying to expand the scope just a wee bit and explore some options.

So, looking at this big mama of a Cell driver, I decided a while back (2019/2020) to see if some reasonable size complete low frequency solution was possible with the AS250, not just a mid bass/low midrange part.

Well, that seems to be doable without a huge effort- and using some parts I had on hand, and an inexpensive test cabinet build.


The cabinet is a modified Denovo Audio knock down 2.0 cu ft subwoofer cabinet, which is in a taller form factor than the typical sub cube, fortunately.

https://www.parts-express.com/Knock-Down-MDF-2.0-cu.-ft.-Subwoofer-Cabinet-300-7086

The main modification is modifying the part of the bracing that goes over the rear panel, so that it's cut out for the PR mounting hole.



But I have things out of order, here- the first step was evaluating possible designs using Unibox, and THEN selecting an enclosure to build. So, this really starts with entering and verifying the driver parameters in Unibox or a similar tool-

The driver unit parameters on the left are entered from the data sheet, and the parameters calculated from that data (on the right, in red) are compared with the available information in the data sheet to verify that it all hangs together and makes sense. This is not always the case. And this also provides for catching errors or omissions in data entry.




And here is the design workup based on choices in Denovo cabinets... and PR's on hand. The "stock" Seas SLR26R looks pretty good- it's got a characteristic more like a QB3 reflex alignment, so there's a soft roll off- but it also has cleaner better damped step response than a typical 6th order maximally flat alignment. With in room boundary lift, this should be pretty clean.

[JonMarsh]

And here's a detailed look at the calculated results expected:



Predicted SPL



F3 = 36.6Hz, pretty satisfactory for music.


Calculated excursion for specified input power and output:




Oddly, though the driver Xmax of 9mm was correctly entered, it didn't get picked up in this graph correctly. Note that there is still considerable headroom for output, with about half the Xmax being used at peak excursion at about 35 Hz with 25W input.

At 100W input, the peak Xmax is touched at 35Hz, with an output level of about 105dB at 35Hz, and 107 dB in the passband.




And the impedance plot, showing the system tuning and a nice balance of the bumps- usually a good clue about the alignment quality.





Next steps will be to install the acoustimass enclosure lining and a bit of fiberglass, then mount the input plate and drivers.

[JonMarsh]

Next up, a review of how to setup the DeWalt DWS780 for 16" depth cuts- for those who might be considering making cabinets like the Isiris top module or Osiris Midrange/Tweeter module. I think this has been discussed before, perhaps just briefly, but for those curious about this, perhaps this would be useful- and I did this again for finishing the top section test cabinet, and this gave me a chance to do a documentation of the process, to inform anyone considering the same tasks.


The DWS780 has two standard rear fence guides which have to be removed to extend the cutting depth. Twist on bolts with handles are provided for attaching these, and are quick and easy to remove.




This is what the DWS-780 looks like with these removed- note the slight tabs at the back of the slots where the normal fences slide in- those will be your working rear fence after fabricating and installing a new cutting board platform.





The elevated cutting platform is fabricated from two 3/4" pieces of MDF that are 24" long and 15" wide. Why 15" deep? It needs to be deep enough to have material to hold it together at the front after making deep cuts, but shallow enough that you can operating the angle setting lock and be able to stick a flashlight under the board and read the angle setting from the scale.

They must be glued together stacked up, to make a piece that is 1-1/2" thick. As an experiment, out of curiosity, I glued them together with Gorilla glue, and I must say that was "entertaining" but not something I'll likely repeat. However, the glue junction is quite strong- undoubtedly stronger than the MDF.




I attached the cutting platform board with 3" #12 stainless screws- it's convenient to drill pilot holes with the board on the saw, then remove and drill out the holes to the necessary depth. I inserted and tightened slightly a screw at each position, leaving them in, to be sure they were all well aligned.

[JonMarsh]

Then, all of the pilot holes have to be drilled out, and the cutting platform board can be attached with the 4 #12 screws.





One of the things I still like about this ten year old saw is the XPS, or Crosscut Positioning System- a fancy name for a light that illuminates the blade in such a way that it casts a shadow that shows exactly where it will cut when you bring it down to the working piece. Newer saws like my Bosch have a laser indicator, but this old fashioned approach works quite well.





The last thing to do to get this ready is to make an initial index guide cut in the platform board. I'm pretty much only going to be making 90 degree cuts relative to the vertical, so for now I just made one sample cut to show you. When making cuts at other angles relative to the fence (we're going to need 78 degrees and 73 degrees on this project) I recommend making similar cuts without the working material first.

[JonMarsh]

Arts &amp; Crafts time...

Time to start putting things together...

A job for the trusty DeWalt joiner...






Epoxy and a light clamp takes care of the rest...




And, yeah, this is phenolic coated BB ply, because it's really been hard to get the normal stuff lately. But tooling BB ply has been in stock in 18mm.

[JonMarsh]

Progress is our most important product, even on a Sunday

Building a test box is not all that interesting, and I'm more a wires and sparks kind of guy than a wood worker, but maybe some of this will be of use to others.

Now I went back to the DWS780 to do the long top to bottom angle cuts on the side panels. These cuts are why I went to the trouble of making the cutting platform that with care grants me an extra 2" in cross cut depth.

I definitely have to pay attention to the drawings and what angles go where- and the two different sides have to be cut with different layout on the saw, due to the relatively short back fence, and the bevels ripped previously on the side panels. getting an accurate cut with the board flipped over, such as for the other side, would not be possible.





Here, I've just completed the front edge angle cross cut for what is the near side, if the cabinet is sideways with the drivers to the left.




And here, the back angle crosscut has been done for that side.



And here, gluing the side up initially, with slow set epoxy (Bob Smith Industries "Slow Cure"). And this is being done on the Husky 52" adjustable height dual draw work table I bought myself just before Christmas; it broke my rule about no new large heavy items in the rental before the move in March, but this has been a real productivity and organizational gem. Well worth the $250 price, and for a few months this Winter, very hard to find in the Boise area; I got the last one available for a few weeks the end of November, in the HD store in Nampa.

[CADman_ks]

Next up, a review of how to setup the DeWalt DWS780 for 16" depth cuts- for those who might be considering making cabinets like the Isiris top module or Osiris Midrange/Tweeter module. I think this has been discussed before, perhaps just briefly, but for those curious about this, perhaps this would be useful- and I did this again for finishing the top section test cabinet, and this gave me a chance to do a documentation of the process, to inform anyone considering the same tasks.


...

John this is an excellent writeup on how to get the deeper cuts. Is this something that can easily be attached in the woodworking tips section of the forum? I don't know how, or know if I can do that...

Thanks again for all of your great contributions!!