Saint-Saëns planar- AKA SMJ-40- time for a project now?

[JonMarsh]

There were a LOT of legacy markings on that; when I figure it's a "take", I will probably mark it up some more as well as put together a BOM in Numbers and output a PDF for that!

Yeah, you'll probably be wanting some sales on Dayton caps and stuff like that! And you might juggle the resistor values and quantities- that's where the Y in DIY comes in, right?

Now, just imagine how out of sync it would be if we used Jantzen Alumen caps in the tweeter crossovers...

🤪

So, if I wanted to induce cardiac arrest in you, I could share a pic of my early "junk bin" tweeter crossover for the 2522 (which I'll update for the test version) with Clarity PUR, Clarity MR, and Jantzen Alumen caps... (plus some junky Jantzen Superior Z and Audyn Plus caps in the two notch networks..)

[JonMarsh]

Note, the midrange crossover update retuned things to reduce the capacitor sizes, but increase the inductor sizes of course- At one time I was thinking about a monster version with 2 PT5010 in parallel, so the crossover network was basically designed for 4 ohms. Then the LPAD adjusted to get the right attenuation for a single PT5010, while keeping the load impedance at about 4 ohms so that the filter worked correctly.

[technodanvan]

I can only imagine your 'junk' bin Jon! I might need to adjust my goal given the cost of crossover components these days, but in keeping with the spirit of the 'PE' build I might stick with Dayton when possible. I do have several of the big 200 uF Solen caps, but I'm wondering about using electrolytic to keep final BOM cost down a bit....then it's just the coils that will add up fast. I'll have to try a few things to see what I can hear. Very excited for this one!

[JonMarsh]

Electrolytics for the zobel would be a "given" in my recommendations...

Now, just to tease you a skosh, here's a pic of the test crossover for 2522 configurations in process, with dual notch filters and defeat switches that had been planned...

[letiennam]

Perhaps the reason comes from the heat of this project. I found that the PT5010 is out of stock at parts-express, have to wait until July to get it back in stock. Would it be possible for you to share the STEP files sooner?

[JonMarsh]

No problem to do that-

However, it's early in the morning and I'm getting ready to leave on a three day road trip to CA to get stuff out of storage, so it would be Monday before I could share. Just PM me an email address to send them to. I'll send the latest versions, of course!

~Jon

[JonMarsh]

STEP files and some comments sent...

[letiennam]

Thank you for your assistance. I received your email. I appreciate you taking the time to exhaustively describe and comment on the current WIP step files. It get me many info so that I would know what characteristics might be useful to look at closely for my selection process in the future.

[letiennam]

Thank you for your assistance. I received your email. I appreciate you taking the time to exhaustively describe and comment on the current WIP step files. It get me many info so that I would know what characteristics might be useful to look at closely for my selection process in the future.
Sorry, due to a network error, my comment was repeated twice

[JonMarsh]

Here's a simple graphic update of what I sent out for the rest of you. Additionally, I put together a project file combining both the MF-HF modules and LF module for visualization purposes. As mentioned many times, I still consider this WIP, not a final product. But it has potential for anyone wanting to plan, or to launch their own version.











Yet to be determined is the final configuration of the base- though I have metal outrigger legs with point assemblies. similar to a Tidal style, I'm also pondering something more like one of Steve's Ardent builds...




Isolators like Danny turned up could be quite useful.

[JonMarsh]

Hey, it's Father's Day, and I FINALLY get to go out into the garage workshop and start getting some stuff done!

But first, a picture I came across that really caught my eye, from National Geographic, related to Father's Day - for all you eligible guys out there! (means something a bit different than the usual version of that expression...)




Daddy DayCare- can be a lifelong task!


Reminds me of my trip to Antarctica...



OK, proof of effort and progress- removing the original design front panel from one of the MF-HF cabinets...





And "surgically" removing the midrange sub enclosure from the original front panel, for reuse with new flush front front panel:







Remember, I make no claims to be a woodworker, just a wires and sparks guy. Tools used were a Greenworks 4.5" battery powered hand held circular saw and my trusty SawStop job site table saw (not the "compact" smaller one)

Progress is our most important product, but slow work takes time!

[technodanvan]

I feel partially responsible for this.

[JonMarsh]

Does that give you a feeling of incredible power in the universe?



I'd been thinking about this also, after doing the measurements on the first cabinet configuration.

You know what they say, move fast and break things. Now I'm breaking things, and making new routing jigs!

[JonMarsh]

Almost finished now with the base panel for the new front panels- easy part was ripping the bare panel into the pieces needed, then doing the outside edge round overs on my Bosch router table.

Then it was time to dig up my old routing templates for the TPL75 form factor, plus make a new one for the PT-5010 cut out hole required for mounting the midrange planar panel flush on the front panel:




There are many nice small routers, but my favorite is still my old Bosch Colt- the square base gives it good clearance combined with extra stability. And the vertical mechanism allows considerable precision when necessary.






The routing bit for this task is a pretty typical follower bit with a 3/8" diameter and 1" cutting depth selected for this task with 1" bamboo plywood.





After marking the front panels with the outer dimensions of the required through holes, a rough cut is made with a saber saw- the routing is to clean it up nice and smooth.





The TPL75 pass through hole is finalized in the same way:




Here's one of the new front panels after the clean up routing is complete:

[Steve Manning]

I recognize that router .... used to have one until I believe it's bearing got tired and I started having vibration issues. Went the way of the DeWalt for a replacement.


As an FYI suggestion for that lovely bamboo that is so fond of chipping, I'd go with a down cut spiral trim bit, it ought to help a lot with chip out. Though, as I say this, I remember that is more than likely your default flush trimming set up! 😁

[JonMarsh]

Yeah, I was thinking of that, too! And this is what I was using with the Maple ply.

And how much I'd rather have some 1" maple ply! But they don't make piano pin boards that thin- 1-1/4" is the skinny version!

Well, needs must, got out some of the more exotic bits today to hopefully finish this up tomorrow- (did work on the tweeter platforms this morning); one template unglued itself (the phenolic has to be roughened carefully even for JBWeld to stick) and that got repaired.

Costco is next on the agenda this morning, and by afternoon it may be a touch warm to work in the garage. Mid 80's. That's why I'm a morning lark, and just finished my outdoor walk for the day! Up at 4:30 AM...

How's the old Ben Franklin saying go? "Early to bed, early to rise, makes a man healthy, wealthy, and wise."

Well, I missed out on the wealthy part; wise? Maybe I'll have to settle for wise ass... But doing better than expected on the healthy part, have outlived all of my FOO for two generations, often by huge margins already...

Beverly and I on a hiking vacation in Europe with Sierra Club in my mid 60's. Doing Ok for my age. At least I didn't look like all those goofy pics I see in advertisements and clickbait articles these days about newly retired people and the guy is white haired with a full beard! I was FRA the year after this picture was taken... but didn't retire, management kept asking me to stay, and that dovetailed with my financial plans. (not wealthy!)

(BTW, I can highly recommend the Sierra Club trips for Hiking from Vienna to Prague, and their "Deluxe" Wainwright trail program in North England- actually covers 120 miles of the 180 mile coast to coast trail!)



Some memories...

Vienna to Prague...

Telc- a village on the way- had some good pizza there.




Prague, near sunset, Charles River bridge




Prague, standing on the Charles River bridge near sunrise:




Along the Wainwright trail, an interesting house view...




At the end of the Wainwright trail, on the East Coast of England....




These were all original shot on a Pentax 645D MF camera. Various lenses, 120mm macro, and some Pentax 67 lenses.


Onwards!

[JonMarsh]

Getting closer, but taking a break this morning to get a walk in- it's going to be smoking hot the next three afternoons!

Got some cool air pumped into the garage though, for this afternoon.

[JonMarsh]

Slow work takes more time...

Now the panel pieces have been basic sanded, driver fit checked one more time, and ready for epoxy glue up.





Yes, somehow I slipped up and didn't get the tweeter quite centered on the panel width. Will have to do a post mortem on that some day, but for now, due to lack of more materials and more time, I'm going with it like this.

Speaking of materials, let me say that though I'm a fan of the strength to weight ratio of bamboo, one must be cognizant of the variability of the boards and material with different processing techniques.

These new front panel pieces were fabricated from "left overs" from the side walls- just barely had enough in one board. This 1" thick bamboo ply was sourced from desktop board pieces on Amazon- no bulk suppliers of bamboo ply in this area. It has a tendency to splinter out a bit at cuts, though only a short distance.

Of course, there is my gold reference standard for bamboo, which is Cali Bamboo Fossilized bamboo flooring. This is what was used in the Isiris build, and it's pretty fabulous stuff, very hard, machines great, and rather expensive.

For machining characteristics, piano pin block maple is my favorite, but there isn't any 1" version of that maple ply, and it's bugger all expensive also. That is used for original front baffles in both the LF and MF-HF cabinets, and for backs and tops. Available in a few variations of thickness starting at 1-1/4".

Not apparent from the photo above, the tweeter platform edge is at a 25 degree bevel, and will have 1/2" adhesive back foam to reduce reflections.

[JonMarsh]

95 outside now today and more on tap- when I took my walk this AM, it was 70 when I left, and 80 when I got home- gives you an idea of how the day has progressed.

The salvaged midrange enclosure from the first cabinet build is now epoxied to one of the new front panels. Should be ready for detail sanding and initial Watco Danish oil tomorrow, but the ARM-R-SEAL won't be until Monday.




Needless to say, anticipation is building for being ready to load drivers and test... and I still have the original development crossovers for the flat panel test enclosures. They might work fairly well... we'll see.

For now, I'm leaving the other cabinet in the initial front panel configuration. Raw Polar comparisons will be made, as well as on axis, with and without crossovers. Recall that to make the first built cabinet configuration work well, both the foam was required plus some additional LCR networks in the crossovers.

Should be an interesting week. Would rather have been doing this in May, but May had to be multiple road trips to CA.

[JonMarsh]

It's beat the heat Sunday Funday, as I say to Steve...


Finish sanding on the "A" front panel is completed, and two coats of Golden Danish Oil applied and wiped down. Tomorrow morning it will be ready for the ARM-R-SEAL top coat.





After that drys and hardens, it's gluing this assembly back into the original cabinet! It feels like this rework took longer than the original construction!

[JonMarsh]

Step by step, inch by inch, slowly I work...

This is just another "proof of progress" post.

Yesterday I applied the 3 coats of ARM-R-SEAL, with drying time that took most of the day.



Which made it possible to finally attach the new baffle assembly to the POC MF-HF cabinet build, that had the original baffle cut off, with the midrange enclosure saved from it.

After surface prepping with 80 grit sanding block to optimize glue adhesion, that was glued up this morning with a slow set JBWeld epoxy.




It should be possible to mount drivers and cables tomorrow, and do some testing, including a check with the first version POC crossovers (I'd better find those today!!)

[JonMarsh]

Hmmm, definitely what I would call the "rustic Idaho look"... not for everyone I'm sure, but we're just working out the acoustic issues for now.

[JonMarsh]

Now, just a little post about Work In Progress, which when I woke up today, at 5, was all I expected to be posting about.



It's getting down to detail assembly for one of the new POC2 front panels... yes boys and girls, that means it's threaded inserts and binding post time here at SMJ Audio West! (AKA AudioWorx).

Being a grumpy old man at times, I get annoyed at how hard it can be to find threaded inserts in the configurations I want, and of course, forget local hardware stores. And folks wonder why I buy so little local...

Sizing is a bit backwards- I need M4 for the tweeter mounting, but something more like M3 for the midrange panel and it's multiple small holes in the accessory faceplate.

I've developed a real liking for the RAMPA inserts made in Germany- fortunately for me, there is a good Canadian distributor. On the left is a free standing M4 insert, on the right one installed in the front panel for the TPL75.



Believe it or not, I bought these M4 stainless screws at a local Lowes Hardware... but forget inserts from them.




I do use both a marking pencil and a spring hole punch to mark my drilling locations using the driver as a location template; then, pilot point drill bits line things up nicely for an accurate hole location. If I did this step before mounting the replacement POC2 front panel on the cabinet, I'll probably just use one of my drill presses, but needs must...




Next up for consideration was mounting the binding posts into the midrange enclosure. This shows the sequence of nuts and washers I use, and my handy-dandy 13mm ratcheting wrench for snugging things up.




Then, installing the pre-assembled cables to connect from the binding posts to the PT6010 driver is the last step at this phase. Threaded inserts did arrive, but when they did, it's too hot to work in the garage. Tomorrow AM.

[JonMarsh]

OK, getting ready to mount the PT5010 midrange panels. Some notes to keep in mind:

• The GRS PT5010 is mounted on the GRS PT5010-FP faceplate. To get an air tight seal on it, I recommend Silicon RTV be used as a gasket sealant, though you're welcome to use more exotic materials if you wish, like Weicon 310, as I used for the wall damper pad assemblies.
• The GRSPT5010-FP comes with what appear to be black oxide #4 flat head machine screws- I've found that, if choosing to use wood screws, I prefer stainless #5 wood screws, as you can usually find at your local hardware store (Ace Hardware in my case)
• To facilitate disassembly and reassembly with experimentation, I chose to use threaded inserts for mounting the midrange panels, with M3 metric screws. not a lot of options out there, but you can pick up an EZ-LOK version on Amazon. My "normal" woodworking sources don't have them. I really don't go out of my way to use difficult to source stuff, it just seems to happen naturally!
• The M3 size requires drilling out the 5010-FP mounting holes very slightly- 9/64" will do nicely. The mounting screws I selected (arriving this afternoon) are stainless M3 button head cap screws, with metric socket.
• I bought once complete M3 kit with installation tool and drill bit and a small number of inserts, and separate packages of inserts.

I like my compact Porter Cable impact driver for installing EZ-LOK threaded inserts with their tool.


Here, you can see the inserts installed:





And with AcoustaStuff in the mid enclosure, then the PT5010 assembly can be mounted.







The Mounting screws should arrive this afternoon; in the meantime, I'll finish up the cables that will connect for test to the crossovers for the TPL75 and the PT5010.

[JonMarsh]

This was what I call a Friday Monday, I.E., busy as a Monday but on Friday, with other things to do...

BUT, the driver mounting and lead installation was completed, and the modified MF-HF cabinet was stacked up with some stools and the other cabinet, to put it at a test height within a couple of inches of the planned finished system height:




Drivers were checked individually, not real surprises, but the data I was really interested in was how this cabinet baffle would work with the POC 1 test crossovers developed using the simple test boxes and baffles...







These measurements were prepared with a Half Hamming window gated at 100 msec (lots of potential for reflections), and with air conditioning running, so distortion may not be as low as it could be... however...




Not too bad...

And another measurement, with a shorter measurement window and 1/12th octave smoothing, the way most folks do it...






One more, with the long window and 1/48th smoothing, comparing 0 degrees and 30 degrees:



These are all with the unmodified POC V1 crossovers, created from the first test enclosures. I'll look at the driver data alone which I recorded, and see about tweaking up the lower end of the transfer function on the mid, and leveling things out a bit more, but so far, this first test with the new front panel as turned out about as well as I could have hoped. BTW, these are NOT the drivers from the original test boxes, those are in the original finished cabinet configuration underneath being used as a stand today.

[JonMarsh]

today was busier than I might have expected- it took a fair amount of time to review all the evolutionary crossover revisions, find the exact ones from which the "junkbin" PT-5010 7L crossover and TPL75 crossover were built from, verifying them component by component, then assemble a network with those midrange and high frequency sections, add in the "junk bin" woofer crossover, then import the newest measured data from the MF-HF enclosure with the new baffle configuration. Last, the tweak the network component values a bit. Nothing difficult, just a number of time consuming steps...

I considered digging out the polar measurement turntable, but I'd already characterized the driver for polar behavior previously, and knowing how consistent their performance is, it seems an "allowable" simplification to just focus on the on axis behavior for now- adjusting the room power response can always be done with an inline voicing filter, like the one I proposed for the Wavecor Ardent build.

So, for fun I'll post pictures of the crossover boards as originally configured (small updates waiting in the wings now), plus the relatively new LF board, and then the results of some VituixCAD work. It looks close enough to where I want to be that further sim tweaking doesn't seem a good use of time- need to see the real measurements, after updating crossover boards and completing the LF cabinets. There is a POC1 PT2522 MOD300 board WIP, not finished wiring it up.


Woofer crossover POC1 4x RSS210HF


PT-5010 7L POC1 Crossover build



TPL75 POC1 Crossover Build


Simulated system SPL response not including PRs




Group Delay + Phase

As you would expect from this, reverse phase on midrange produces deep clean nulls at the crossover points.





Impedance curve


This benefits from an LCR zobel network between input and ground on the tweeter board, to minimize the impedance bump in the crossover region, and a large zobel damping network in the woofer crossover, which minimizes impedance and phase current excursions.

[technodanvan]

You're making some serious progress Jon, I love to see it! The woofer XO is kind of funny though, unless you look at certain things it's kind of hard to tell just how huge it must be...since almost everything in it is quite large. Easiest way is to compare the resistors to the mid and tweeter sections...though even the mid looks pretty serious.

[JonMarsh]

Yeah, it's a bit of a brute, Danny, but sized to fit on the floor of the LF enclosure and fit through the input panel opening. It's too big to go in through a woofer hole, but the PR openings would probably work in a pinch!

Now some detail work this afternoon, creating delta BOMs for. updating the the MF and HF crossover boards- mostly resistors, adding a few small caps. And checking to see what I have on hand and what I need to order next week!

The next big push in the "shop" is assembling the router fixturing for the rebates in the sides for positioning the braces, and fabricating the horizontal braces, and some tweaking to the woofer front panels.

With the heat we have here, I'm motivated to get up early and get busy right away!

[Mikerodrig27]

Lots of great progress! I recently took a tour of PS audio as I live near Boulder Colorado. I was really impressed with the sound of their FR30 reference system. I listened to around 6 or 7 tracks. They use a pretty large REL sub in the back of the room opposite of the FR30's which they had blended very well. I am excited to see what your listening impressions are once you finish up your build.

One interesting thing the tour guide mentioned was that the FR20 should be pretty much the same sonically outside of how loud it can get.

[JonMarsh]

I lived in Boulder CO from late 1972 until 1985. A few stories to tell, most already told on the side in other posts. Knew the Avalon and Ayre Acoustic folks back then.

[JonMarsh]

The FR20 should be fairly close in many regards, IMO, but besides the sheer level out output, one thing the FR030 has an advantage in with the four driver woofer array is essentially a short line array which staggers the floor bounce problems across a wider range of frequencies with a more smoother response possible- Floor bounce creates problems because it is a strong signal compared with the direct sound from the woofer, but it is delayed and so you get comb filtering effects when it is combined with the direct sound. Two woofers, spaced correctly from the floor, help mitigate that effect- four is even better. In an old project, "Modula Extreme" that predated the Isiris but used the same midrange with a waveguide tweeter, this was investigated because the initial straight forward build used two cabinets for the woofer placed at ground level had some "issues" with behavior.





Close up measurements didn't show problems, but... as it turned out...

OK, while I was talking to ThomasW earlier this AM, I stacked up my Modula Xtremes on a new pair of PE boxes, just to see how the room interface for LF would be with the revised woofer positioning, and the imaging and overall balance.

My brief listening impression was that the midbass was a bit smoother, and that we'd picked up a third to half octave in the bottom end. Now, as they were previously nearly boundary loaded on one woofer, I did not expect there would be an improvement in LF response picking the whole thing up off the floor. Seemed like a classic case of placebo effect- you hear what you wish you would hear.

The microphone doesn't lie, though, at least not if you treat it right, so that was next.

This is a 2 meter measurement, gated at about 160 msec, in room. Damn, if it doesn't look like the midbass is smoother and we picked up a third octave in the bottom end- with no other modifications.

Am I lucky or what? Like I said, Jed must enjoy me watching me walk around stumbling in the dark, barking my shins now and then and also coming on a little gold at other times.

Well, it seems to me we've at least got a valid argument for using a pair of the 1 cu ft boxes as speaker stands... but I think doing a full addon with the crossovers relocated will be in the cards now. Sheesh, if I'd come up with this response curve just by doing the full mod, I'd be happy, but now I suspect there may still be a little more performance to wring out of these with making more of the woofer modules available to the woofers.

The positioning and spacing of the woofers is pretty important for optimum results- further experimentation led to the Isiris.

Re-inventing the wheel, you could comment. OTOH, I should note this dates back to 14 years ago... I determined that woofer spacing and height ratios of both to the floor were key to getting optimum results. This also factored in to the design of the Wavecor Ardent.

BTW, just for reference, this is what HiFi News in England, a sister publication of Stereophile, measured for the FR30, using the same equipment configuration as Stereophile employs.




I think it's the relative smoothness between 70Hz and 4 kHz that gives the FR30 a good balance for a lot of music. I think it can be improved on, though. BTW, the "bump" on the left is the PR output; the tuning seems a bit low and disconnected from the overall system character. I'd hazard a guess that there might be better subjective integration and output if the PR tuning was up around 30-32.

[JonMarsh]

You wouldn't think that checking all the parts to tweak for updates and modding the MF and HF crossovers would take all that long, but there were Honey-Do distractions like assembling a Gazebo that slowed things down... Fortunately I had all the parts I wanted on hand, or very close solutions, you know, the kind that are good enough for Government work? (well, maybe not NASA....)




Of course, the air conditioning was running, wife was having a fairly loud conversation from her Den room with another Russian gal friend that happens to have the same first name (yeah, confusing...). So the noise floor isn't what it could have been under more ideal conditions.

But it's encouraging enough to say set this aside for now, and only revisit when the LF boxes are ready and it's time to integrate the whole ball of wax!

[Mikerodrig27]

Ahh, I see. The woofer array does make sense. The mid/tweeter portion of the FR30 was pretty high above my ear level. I wondered how things would sound if the top box was closer to ear level. The bass was really really good although it was assisted by a pretty large REL sub.

I am loving your progress!

[JonMarsh]

The 4x woofer array wired in series parallel for a net impedance the same as one woofer also conveys 6 dB of acoustic sensitivity increase- from 85.6 dB/2.83 VRMS to about 91 dB (+ 6dB for this configuration)

[JonMarsh]

Now, you know, being the sort of guy I am, it's hard for me not to consider it "diagnostic" that the FR30 demo you heard at PS Audio used a large REL sub to reinforce the low end.

However, that is not surprising to me, given the HiFi News measurements.

It remains to be seen how the low end on this design will work out in reality, but the Unibox analysis is fairly promising...



The RSS210HF subwoofer driver is an interesting part, straddling the line between subwoofer driver and woofer- as the QNF response in a small test box shows, it is far flatter and more linear than most 8" woofers, to say nothing of 8" subwoofers.




The VC inductance is quite low, but the overall physical parameters that impact LF extension are definitely in the subwoofer class.

However, unlike most subwoofers, which lack focus on controlling impedance rise, the RSS210HF is exceptional in this area, and as a result has very good midrange distortion behavior.


Fingers crossed, but you can see why I think putting some time into this is worthwhile.

[JonMarsh]

BTW, the PR choice could be either the RSS265-PR or the new Seas SL26R-XM003. Seas has a reputation for striving for high Cms linearity in the SL26R series, and even did a recall on a batch of the older version that didn't live up to normal expectations. The XM003 is their most recent version, and was developed rather specifically to work with the LROY woofer. The irony here is that I'm using RSS265-PR weights with it, as though the part has a good data sheet with curves for various steps of PR mass, it does not ship with any extra weight disks.

[letiennam]

Your progress catch some serious, I'm really excited to see it! but pt5010 is still waiting to be back in stock

[JonMarsh]

Yes, you and a few other people. Some did buy them early in this development effort... but you are new to HT Guide. Note there was a Design Study phase for this also, posted in that section

[JonMarsh]

This little post is just about some mechanical details to watch out for if you plan to work with the RSS210HF in any sort of build- but of course it's relevant to this one, 8x over!

As you folks must realize by now, I think the RSS210HF is a very nicely performing driver, but constructing with it requires some attention to details...




Why do I say this? It's because given the cone and surround size, the overall chassis size is rather "compact". That is, it would have been easier to mount if it had been an RSS225HF- recall the part numbering on the woofer. Noting my markup of the RSS210HF mechanical drawing, and one of the mounting holes-

• The actual width of the mounting flange area is relatively narrow...
• The mounting hole is 4.5 mm; in imperial dimensions, 0.177", for which the largest standard size bit you can fit through this hole is 5/32", with only about 0. 05" wiggle room. And it's pretty close to the inner edge.

So, let's look at our handy-dandy Viadon screw and hole chart... (y'all keep a copy on your desktop at all times, right?)



Well, what we can see is that 8-32 is really just a bit too large, but M4 seems viable, and does give a bit more meat on the shank than a 6-32, which, to me, seems a bit puny for a subwoofer driver with as substantial a magnet as the RSS210HF has.


Now, a quick review of the front panel design-




This design is based on providing as wide a possible flange mounting surface as possible, which basically means using the minimum inner radius possible. I.E., a very precise snug bit on the inner dimension of the driver.


So, of course, that means you either have Steve do the front panels with CNC, or you dig out your trusty Porter cable router with it's infinitely adjustable circle routing fixture, which as a bonus has really good dust collection also...




Yes, that knob on the fixture is the jig clamp; set the distance on the underside between the inert pin and the outside of your bit, and tighten down and double check. That's part of why they call it the "Perfect Circle" jig; with care you can get stuff within a couple of hundredths of an inch.

The 4.25" radius on the outside leaves a tiny bit of space on the outside, just enough that you can check to be sure you're snug as a bug in a rug on the inner route when you test insert a driver. (Hint: You can use an RSS210-PR as your mechanical test piece- I have a couple on hand for another project, and it's a lot easier to use as a test jig than the much heavier and deeper subwoofer driver).

Now, after you have your front panel routed and assembled and checked out, it's time to drill the pilot holes for the inserts. I took a two step approach to this, first using a 5/32" bit that occupies nearly the entire mounting hole, and using the first hole drilled with a second sample of the bit to "lock" the RSS210HF woofer position from moving (we don't want any of the holes misaligned to each other, in relative angular terms).







Then, using a pilot drill bit for precise positioning, drill out the holes further to the size needed by the Rampa SKD30 M4 inserts, which using a dial caliper, turned out to be pretty much dead on 0.25". The outer diameter is 8mm, or 0.315". Insertion and tightening is done with a 4mm hex wrench.

[JonMarsh]

OK, it's Monday morning, time to show that I'm not just some other retired guy sitting in front of a TV, but as the Blues Brothers would say, on a mission from God! Or a local representative... or maybe just an aging Sith Lord!

The plan for today took a drive into the weeds as I had to use the bench I was planning to tackle doing the back panel routing on for to finish up some gluing fixes on another part.

So instead I shifted gears to reviewing the LF cabinet side walls and documentation,




and setting up to trim the rough cuts to final outer dimensions. The width was just fine, as that is easily ripped on my job site SawStop table saw, but the panels had been cut a bit long, and needed to be trimmed to 40", as close as reasonable.

Since my table saw won't rip to 40", (please Santa, where is that new one I've been asking for, for so many years?) this is going to take a bit of effort to ensure the accuracy I desire, though truth to tell, with my double follower spiral cut router bits, cleaning up a little overhang is no big deal. Still, it's the principle of things, right?


So, I collected my wits and the best tools I had on hand to tackle this, which includes a long large straight edge square, my favorite angle ruler, a Bora NGX Clamp Edge bar, and my DeWalt 7" circular saw with a fresh 60T blade.



The Bora NGX was purchased two years ago specifically for this project- the guide clamp is what sold me on it.





I keep telling myself I should buy a new super duper battery powered 7" saw, should be lighter and quieter, but you know, old ways die hard....

Now, this is not a negative kerf blade, as I prefer for making finish wood cuts, but it's a brand spanking new 60T blade, and the way I'm doing the cuts, the top side is the side going on the inside of the cabinets. So no harm, no foul, I think.




Key things I liked about this DeWalt is the design of the base and the adjustability and pretty accurate dimensional stampings. But the motor is a classic 120VAC saw motor, which means breakout the ear protection. And no dust collection. So sue me...


the dimension for the location of the saw cut is a nice even 5" from the left hand side of the base, making setup easy after measuring from the distant side, to get the clamp setup at 35".



Good tools and a thoughtful setup means you can get cuts pretty much as accurate as your rulers...


Just remember - if you really want experienced advice on how to do stuff like this, check with Steve. I'm just a wires and sparks guy- think high frequency resonant converters with wide bandgap semiconductors... still get called up on that stuff for conference calls with my former colleagues.

This wood working stuff, well....




And this is the First Time for the Saint-Saens!

[JonMarsh]

Confession to make- blaming Murphy's law, of course

"Anything that can go wrong will go wrong, and at the most inconvenient time."

Well, TECHNICALLY, nothing went wrong with the work, but it could have proceeded differently- one of the challenges of having a number of tools one only uses occasionally means that occasionally one can't lay one's hands on them when desired.


So, of course, first thing this morning, what should turn up, when checking for a particular DeWalt orbital sander, but this saw...





Yup, the battery powered one with the really nice cast base and adjustment modes... THAT saw! With a nice Diablo blade already installed... I'll be more careful about where it gets put away this time, but OTOH, I may not need it the rest of this project.

[JonMarsh]

The routing for the LF cabinet side panels has commenced, starting with the PR openings, will proceed next to the rebate grooves which the interior braces will fit into.

As always,

For those who have received preliminary WIP STEP files, NOTE THESE ARE ALWAYS SUBJECT TO UPDATE BEFORE FINALIZATION!


For this stage of work, that means tweaking the inside and outside hole diameters for the PR to facilitate normal assembly, after measuring the specific drivers to be used. This is necessary for my build because I am using the Seas SL26R XM003 version of PR, whereas most of you have indicated using the very similar Dayton RSS265-PR, which is quite similar, but NOT IDENTICAL in dimensions. The Seas is slightly larger and I'm adjusting accordingly for my proto build.

[JonMarsh]

I'm in the situation of developing parallel cabinet tracks with the 3D designs- and this afternoon creating 2D drawings for some of the more complex braces.

Reasonably happy with progress on the PR updates and side wall fabrication. Whiteside 25/32 bit for the flange rebate (will be used a lot on the inside for tracks for braces), CTM 1/2" solid carbide spiral up cut bit for the cut out. Using the well designed plunge step fixture built in to the router to step down the cuts deeper. But face it, slow work takes time, especially this time of year with other chores to attend to!

[JonMarsh]

I've been getting a few PM's regarding this current work and current tools, for folks that seem to have the mistaken impression that I'm some kind of woodworker? Not just an over active retired Boomer with too many power tools and ideas?

Well, I'm going to do my best to address a few of the questions... starting with why this router? And where do you get them?

Should I start with the good news or the bad news?

I checked around, and it seems you can't get this router anymore- not from Porter cable or anyone else, but you can get parts for it.






OK, why did I pick this one (have two, actually, last one bought in 2020) and what is key about how it gets the job done?

Many routers have nice depth cutting turrets for stepping repeatedly though a useful range of cutting depths (in combination with the depth rod, which oddly is missing from this factory illustration).

Many routers do NOT have this function, but all plunge routers should, and the mores steps the better. 6 of them here...





Others mentioned the spiral up cut bit- where to get? Probably not your local Big Box store... I use Woodcraft, Rockler, Amazon or Ultrashear online. This is a 1/2" body solid carbide CMT bit, 191.507.11, purchased from Amazon.






Brings the chips up nicely, and very smooth side walls and bottom. For this work, the Final Cut is set to about 3/16" remaining material.

Here you can see the final plunge depth partially cut out.




Now the, about that "Perfect Circle" jig. There are a lot of circle jigs for routers, and others from Rockler and other companies that look somewhat like this one.

BUT!

This one is sold a company called Mobile Solutions, and it's specifically designed for cutting a wide range of speaker cut out circles or rebates. This only becomes fully apparent in comparison to some similar looking jigs if you flip it over...


Well, HTG is giving me a 403 error on uploading this picture.

[JonMarsh]

Let's try that pic of the underneath of the router fixture here...



This one I could upload...

The point really, is that the part of the fixture with the routing point pin can be swapped 180 degrees around. So, the routing pin can be just an inch or less away from the bit, or flipped around to the far end of the jig fixture.

And note the multiple clamp screw holes- the knob for securing the jig can be moved as desired, and furthermore, you can go down to your trusty Ace Hardware and buy a Knob with a 10-24 bolt and a small stack of washers and secure it in more than one place if you wish.

So, for me, this circle fixture, being infinitely adjustable over a wide range and very easy to setup for the specific distance, wins hands down.

Now, for the bad news... it's pre-drilled for that Porter Cable Router. You can drill it for other routers, of course, but that's on you.

YMMV, of course, and this is DIY, so ALWAYS feel free to do it YOUR WAY, and you can sing the old Frank Sinatra song along while you're doing it, and singing to yourself, "I did it my way..."

[technodanvan]

Really nice looking jig Jon, too bad it's PC only.

[JonMarsh]

All you need to do is drill holes for any other Router mounting setup.

I'd probably recommend a DeWalt DW621, as it has pretty good dust collection also. Not as nice a plunge turret though.

[JonMarsh]

Moving on with things, my DeWalt DW611 is the router of choice, to clean up the 3/16" lip at the bottom of the PR holes. It's larger than the typical 1/4" shaft router, with an extended base that makes keeping it stable a lot easier.


after cleaning out the bottom lip, the moment of truth comes- checking the fit of the PR! Of course, if we've paid attention to the dimensioning and prep work, no surprises at this point.




Don't rush to pull the PR out after getting it centered, because next up is marking the hole locations, in this case, with a fine point Sharpie.





Next, I center punched the hole locations, then drilled the pilot hole for the insert using a 1/4" Pilot Point Tip drill bit.

Then we're ready to screw in the M4 Rampa threaded inserts.





Of course, if you have mild OCD disorder, or you're a Virgo like I am, you'll probably want to check the alignment of your insert set with a PR!

[JonMarsh]

I'm finishing installing the last of the PR inserts today, and doing some J-B weld work this morning before it gets to hot- then, finishing the 2D drawing updates and should be printing out the updated large size prints for work starting Monday.


In the meantime, a visual hint at what's to come...

[JonMarsh]

Sunday Funday Prints Day-

Last of the fabrication prints updates (hopefully!) and time to release to manufacturing! Well, no, just prototype fabrication!

[technodanvan]

That speaker is soon going to join your printer in the "extra large for it's class" club.

[letiennam]

I was really lucky to visit PE on the last weekend, which was also the last day of the 14% discount. The project was so attractive that 6 drivers were ordered. Gentleman - Topic owner has made great strides in the project. I can't wait to see a picture of him standing next to these speakers, all are gems.

[JonMarsh]

Thank you for the kind words, and congratulations on getting the drivers at a good price!

We have a saying, that the early bird get the worm- you may not have been early, but you still got a good price!

My wife thinks of me as an early bird, but then, she is a night owl. So I have my "early" routine which includes making breakfast, checking news and emails, and getting a walk in at the coolest time of the day...

Of course, on the Internet, we need pictorial proof! Today's is here...




all the haze in the atmosphere from wildfires in Oregon makes for interesting sunrises...

The western view is not so spectacular, but the Oregon LA Haze is quite visible... some of the smaller fires in Oregon are only 30 minutes away.