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

**JonMarsh** · 07 October 2024, 16:15 Monday

OK, next step under way- connecting all the RSS210HF to the pre-coded/labeled driver leads, and doing a DATS impedance check to make sure things at this point look at least SOMEWHAT like what they should...

At this point (a little late in the game) I'm looking at all those drivers and magnet assemblies, and wondering why I couldn't find a nice 8" Neo magnet driver to use...

Then, completed- RSS210HF's connected and mounted....

You notice I did manage to flip the cabinet around, without much swearing- but the empty PR holes were essential for "getting a grip on things"!

Ready for installing two layers of denim insulation over the crossover, and mounting the PRs. Something to look forward to tomorrow morning!

That, and get out my catalogs and look for a good Neo 8" woofer! This puppy is heavy!

**JonMarsh** · 09 October 2024, 09:27 Wednesday

BTW, I DID spend a bit of time yesterday trying to find a good Neo magnet 8" woofer/subwoofer that could compete with the RSS210HF- no joy! Not that I would change the design at this point, but more for other folks future reference...

**JonMarsh** · 11 October 2024, 09:11 Friday

while working like mad to get ready for my "assistant team" to come over for a couple of hours late Thursday for literally "raising the roof" for the gazebo, I decided I needed a little inspiration to keep my efforts going, and stacked up the MF-HF enclosure with the LF enclosure...

It did have the hoped for psychological impetus, and Saturday I plan to get back to working on it. Meanwhile, as agreed with wifey, it's 5 days a week on the gazebo, so today is another, but the last for this week!

**technodanvan** · 11 October 2024, 09:16 Friday

Hey Jon, I see that you seemingly have the tweeter flush with the woofer cabinet here, but I seem to recall Steve and I concluding the mid should be in the same plane as the woofers. I'm talking physical plane here of course, not acoustic. Just curious if it makes a big difference.

**JonMarsh** · 11 October 2024, 11:33 Friday

The most critical point for phase as regards dimension is the Z axis alignment of tweeter and midrange- I had a long discussion about that with Steve. As explained to him, my testing with test cabinets has ALWAYS been with the midrange recessed relative to the mounting plane of the woofers. Just go look at how the first version of the MF-HF cabinet is constructed, and this was developed based on both my own tests using independent test baffles and analysis of the available detailed cabinet depictions of the FR30 on HiFi News.

Of course, this is DIYW, I'm just one guy... an ex rock and roll musician with a psych degree! And into wires and sparks...

**JonMarsh** · 11 October 2024, 11:43 Friday

And posted July 2023...

Machining the rear offset bevel...

recall panel front is 1.25" Maple ply + 1/2" solid maple board; 1/2" birch ply inset for mounting the GRS planar midrange using the accessory GRS mounting panel.

After assembly of inset mounting panel (from July 2023 post)

**JonMarsh** · 12 October 2024, 12:17 Saturday

It's the weekend, so in theory I get a pass from working on the gazebo! (but I will this afternoon)

Focus has been on getting ready to mount, and mounting the PR's on the first test cabinet.

First was installing 2" Denim insulation over the LF crossover. I would have liked two layers, but as it turns out, there just isn't really room for more than 1....

Looking back towards the input plate:

Looking forwards...

**JonMarsh** · 12 October 2024, 12:23 Saturday

Now, the real job... I pulled up another one of the larger moving dollies, and laid the cabinet on the side, I hadn't tested my "alignment" skills yet after installing the Rampa inserts, and figured it would be easier with the PR openings pointed up.

No surprises, went together just like I knew what I was doing all along....

Then I brought the cabinet back up to the vertical for the second two PRs to install. I cheated doing that- this puppy is getting heavy, and I did the initial lift using the 1.5 ton aluminum jack on the left, which is normally only used for my NSX. Worked like a charm, made the lift easier, by improving the angle.

**JonMarsh** · 12 October 2024, 12:40 Saturday

This didn't turn out to be as tricky as I thought it might have been- of course, if these were 10" subwoofers instead of PR's, it would have been another story!

I found it easiest to leave the PR out a bit and insert the screws through into the threaded inserts- get four lined up, at 90 degrees, then the others are easy.

Left side view of cabinet:

Right side view:

**JonMarsh** · 12 October 2024, 13:44 Saturday

OK, I don't usually run DATS through a crossover, but what the heck, given what I'm doing with the LF Zobel compensation network and given it's all wired up, lets take a look....

Well, it seems to be doing things I pretty much expected and hoped for.

The box Fb is in the upper mid 20's, the upper peak is in the same range as for the single driver test box, and slightly lower than the Unibox calculation for 110L. The most notable thing in my mind is how relatively mild mannered the current phase response is over the LF operating range, which is what I was hoping for with the LF Zobel network.

**JonMarsh** · 13 October 2024, 09:46 Sunday

One thing I want to emphasize for anyone following this thread with "intent", is that what I'm reporting is WIP- Work In Progress. Not finalized design.

In particular, the LF development has not followed my usual methodology- you could say it has been more speculative, in order to facilitate a shorter focused construction process.

What that means, instead of building up a full size test enclosure for four woofers and four PRs, measuring it as desired, and then deriving a crossover, and installing that in the prototype or using it externally, I've used this design path which I would call more speculative and using more simulation- something more like what I used to do developing high frequency SMPS power supplies. VituixCAD offers some capabilities which makes this possible and interesting, but perhaps not foolproof!

Things worked out this way:

Modeled a RSS210HF + RSS265PR and Seas SL26R PR
Built a single driver test enclosure for both woofer and PR
Verified expected LF performance
Measured Woofer output in a Quasi-Near-Field configuration, which duplicated the published infinite baffle half plane factory measurement
Used the QNF data in VituixCAD with the baffle simulator function and four "woofers" (the QNF source data) on a baffle matching the construction plan
Used this simulated baffle + driver output data at the shown microphone position and distance (near ear level) to develop the crossover.

Here's what the baffle diffraction tool work looked like:

Now, I've done my first test with all the hardware, and it's quite close, but I believe I need to disconnect C5 (47uF, schematic above) to hit the target LF transfer function. So, today or tomorrow I'll be popping off one of the PR's to get convenient access to that part of the crossover, and disconnecting that cap, then button things up again and remeasure.

And thus, slow work takes time, but this way I had a complete test crossover that was pretty close to install in the cabinet while building it. With the removable rear panel, I can, if needed, swap it out, but I don't think at this point that will be required.

**JonMarsh** · 13 October 2024, 19:22 Sunday

Yes, slow work takes time!

And I did confirm, removing the 47uF cap gets the transfer function where I want- will post a graph tomorrow.

**JonMarsh** · 14 October 2024, 07:31 Monday

And here's the graph of the woofer crossover response, at distance, on the listening height, minus the 47 uF cap. This was a relatively long window measurement and only 1/24 octave smoothing, so there are a lot of room reflections in there.

**letiennam** · 16 October 2024, 05:38 Wednesday

Originally posted by JonMarsh

Yes, slow work takes time!

And I did confirm, removing the 47uF cap gets the transfer function where I want- will post a graph tomorrow.

I'm sorry if this question is a bit stupid, can you share your experience on why you know that it's a matter of removing the 47uF capacitor?

**JonMarsh** · 19 October 2024, 14:43 Saturday

Hello Letiennam,

Two reasons-

I'm an experienced electronics engineer, was a "Distinguished Engineer for a German semiconductor company. So, it seemed likely to me that just reducing the size of the shunt cap in an LR3 passive filter by 25% might get me where I needed to be- total capacitance was 200uF, consisting of a 150uF cap and 47 uF cap. I'm very familiar working with passive crossover filters, been doing it since the 1970s. (Geez, kind of dates me, doesn't it?)
I checked the effect in the simulation in VituixCAD, and it looked like it shifted it about as much as needed.
Note, I was always just working with simulated data for the 4 driver woofer array, created by measuring one RSS210HF in a test cabinet in QNF (Quasi Near Field) mode, to get a data set that looked like the half plane infinite baffle data the manufacturer supplies, and then used that with the diffraction evaluation tool in VituixCAD to model 4 drivers on the baffle shape I planned. Oops, this was three reasons!

Now, I'm also going to be tweaking the LCR zobel filter a bit, because I just caught that I forget to adjust the DCR of the 10mH inductors to the correct value, and I need to lower the external resistance. However, this shouldn't (as far as I know) impact what's going on at the crossover frequency, but it does at the Fb and the driver impedance peaks.

Step by step...

**JonMarsh** · 19 October 2024, 14:53 Saturday

OK, a bit of progress, it's the weekend, so I get to work on my own stuff instead of the gazebo (and it's almost done, anyway- more ladder work yesterday propping horizontal beam struts tying two of the right angle rafter struts together in the opposite large rafter panels)

Finished adding components and wiring up the Mid Frequency POC V3 test crossover board- (with even a modicum of luck, I'll be testing it tomorrow, maybe the whole fandango for one cabinet! No where near as pretty as Steve's builds, but then, it's just an electrical prototype, right?

I almost can't believe that is ready to happen, it's taken so long, and so many interruptions - like this!

**Steve Manning** · 19 October 2024, 16:06 Saturday

Weren't you supposed to put a tree on that thing when you topped it out? 😁

**JonMarsh** · 19 October 2024, 18:19 Saturday

Originally posted by Steve Manning

Weren't you supposed to put a tree on that thing when you topped it out? 😁

Yeah, but not until spring time!

**JonMarsh** · 20 October 2024, 15:50 Sunday

Well, it's Sunday Funday, and definitely not a day of rest...

Since the POC V3 MF build is complete, I went back and tweaked up the POC V1 TPL75 HF crossover, brought it up to a similar configuration as my last VituixCAD work.
I also wanted to test some different stuffing configurations, and collected those materials..
Then I got to work...

The winner on the stuffing wars (not to be confused with Turkey stuffing, that's a month away) was pure acoustastuff, after 3 different trials, looking at raw performance, so of course the next logical thing to do was to hook up the V3 POC MF crossover.

Yes, that looks like it will do... for some reason, the top end isn't quite as smooth as the original first small test enclosure, but for now I think I can live with it.

Next, connect up the substitute HF crossover V1 with some mods, see if we're going to get lucky...

Looks like we ought to knock down the top end by 2-3 dB...

Adding one extra shunt resistor, not bad... still a ways to go, and mod the full LPAD for the full V3 build.

Gee, since I have an LF cabinet with crossover, even though I know the LCR zobel needs to be modified due to using the wrong DCR for the inductors, why not give it a shot for the first time...

Got some room issues, plus that built in LF loudness compensation to fix, but hey, measured on the listening axis, looks like I just need to bring down the MF+HF by 3-4 dB.

So, some fine tuning to do, but nothing intellectually strenuous!

And you know, the Best of Fourplay sounds pretty good even like this- a lot of clarity across the band. Now, with the drivers like they are, at this point the vertical listening window is narrower than a small MT, but from seated to standing seems pretty good. Well, up to 6ft- mic says higher up things get a bit out of balance- but that's still just at 2M distance.

So, next up, tweaking levels on the Mid, building the V3 HF board with tweaked levels, and going in to the LF cabinet and changing some resistors...

**tktran** · 21 October 2024, 06:11 Monday

Originally posted by JonMarsh

BTW, I DID spend a bit of time yesterday trying to find a good Neo magnet 8" woofer/subwoofer that could compete with the RSS210HF- no joy! Not that I would change the design at this point, but more for other folks future reference...

Did you have a look at the NE225W by any chance?

I know it’s not available in unit quantities. But a group buy of the Peerless/Tymphany compression driver DFM2535R00 over at diyAudio makes it clear- if we buy it, they will build it (and sell it)

**JonMarsh** · 21 October 2024, 08:02 Monday

I searched for the NE225W-04 and -08- formerly carried at PE, they list it now as no longer available, while they have many other Peerless products on hand. The 10" version does not have the sort of surround design that lends itself to a linear long throw, though it's available with 100 piece order. The 8" version is listed as obsolete at Digikey. The NE225W had a listed Xmax of 7.6 mm, but the surround is rather narrow for that rating... and spec wise, it's something of a monkey coffin driver. And not as well behaved above 700 Hz as the RSS210HF.

Like I say, I've compared a LOT of 8" woofers/subwoofers, and it's tough to match the RSS210HF.

**JonMarsh** · 23 October 2024, 10:50 Wednesday

Been a busy week on many topics, but those include reviewing the Midrange/HF data, adjusting levels in VituixCAD, tweaking up the HF POC crossover to official V3 status, and ordering more parts and preparing a new board layout in the same 12" x 8" form factor (for BK1 phenolic boards.

A number of component changes/tweaks, and the MF-HF phase tracking is improved and the reverse midrange connection null is even deeper. Plus levels have been adjusted that should bring it in line with the woofer array, based on the last measurements.

Layout is somewhat similar to the original V3 version that I hadn't finished, but with some parts deleted and a number altered in value, things got juggled around. Gotta go get some J-BWeld from the hardware store to glue up connectors now... those will need to sit 24 hours.

**JonMarsh** · 27 October 2024, 08:44 Sunday

OK, a little Sunday morning teaser, was busy yesterday shopping at Costco, generating training materials and giving a 2 hour Zoom training, but also got the remaining HF crossover parts in by UPS, and got those glued those up- should have some time for wiring this morning before going back to the gazebo!

Now I've also got to remind myself to check the updated stuff for the MF board, and tweak that also.

**JonMarsh** · 07 November 2024, 10:07 Thursday

Well, there have been a lot of "distractions" lately, the most recent being taking my Russian wife in for an eye exam at Costco yesterday- she's nervous about navigating anything like that, so I'm always the chaperone. and tour director.

I've also discovered that my experiment with VituixCAD and baffle diffraction modeling of the response using the QNF measured data (which does a very good job of replicating the factory IB data) didn't work out satisfactorily... probably errors on my part, so I will go back and look at that again later.

So I pulled the crossover board, (not a simple task, involved removing two woofers, all PR's, and the rear panel, but doable with patience) and made a series-parallel wiring junction fixture from a molex connector to just connect the woofers to the cabinet input panel.

And performed a lot of measurements, won't bore you with all the details, but here are two sort of representative ones-

This at about the front baffle width from the 2nd driver from the top...

And this at a distance, about 1 m.

I believe some of the differences in the response above 1kHz lie in the differences in the impact of variation of out of phase cancellation from other drivers in the column.

How am I thinking this may all pan out? Well, for now the MF and HF builds seem to have taken their marching orders to heart, as regards measured results. No update there.

This is what I plan to assemble for the next LF test crossover, externally for now, separated into two boards for impedance LCR and actual LF filter, to facilitate updates (and possibly reduce the work involved!). More parts already on order, though if I were willing to use AWG10 air core I could build it now... just might consider a scrap board test!

With the current room placement and LF data (neither are optimal) things would probably look like this:

From 25Hz to 40kHz, impedance is mostly around 4-5 ohms, with a couple of very brief passes near 3 ohms.

Very deep wide reverse midrange nulls a MF and HF crossover points. Staying on top of that.

Just may have to consider trying out that AWG10 air core build while waiting for the other parts....

**JonMarsh** · 07 November 2024, 10:59 Thursday

One other point worth mentioning- with the promised tariff raises of the incoming administration, there are a lot of audio products, drivers particularly, which will likely see substantial price increases. Of course, most parts from GRS- and some from Dayton Audio- Epique series are made in China, but RSS series are made in Taiwan, and I haven't read about any planned tariffs for Taiwan, but you never know...

**JonMarsh** · 16 November 2024, 17:10 Saturday

Well, there sure have been a lot of distractions and unplanned efforts lately, but there is some slow build progress on the LF POC V2 test builds...

The LF filter board is wired up and ready...

But the LCR Zobel board still needs wiring- note there are two of each of these on hand, with hardware mounted. Hope that's not over confidence on my part.

Hopefully, POC V2 will work to my satisfaction...

**JonMarsh** · 17 November 2024, 13:28 Sunday

OK, Sunday Funday is not a day of rest- need to catch up from too many unexpected tasks this week.

Impedance sweep check confirms desired behavior, with minimum Z of ~5 ohms at 60 Hz.

**JonMarsh** · 16 December 2024, 18:02 Monday

I can hardly believe the last time I had something to post was before Thanksgiving, but then there is a lot going on this time of year, including a trip to Seattle, and getting ready for jolly St. Nick- if he shows up! As well as trimming up the revised crossover for Ardent D with vintage NIB RS52AN.

well, what's knew is that a test platform for the LF POC V2 crossover has been fabricated, wired up, and now tested with the last state of the MID-HF upper module and crossovers...

Steve might or might not like how I fabricated this- at least it's in a nice line that could be put on the back of an enclosure with or without a viewing window!

Mounting is optimized for prototyping and quick removal and updates if needed- 4" wide velcro strips, two on each board.

With everything wired and reconnected, first check was just LF functionality and a check on the basic POC V2 developed with measurement data. This was done at about 2/3 of a meter, which tends to discount the PR output and emphasizes LF below 100Hz, as there is little out of phase stuff due to wavelength from top and bottom drivers competing with the center parts.

The result was pretty much what I was expecting and looking for, roll off looking OK, keeping in mind measuring a system like this is bit more challenging in some regards than a 6" two way!

Next up was all drivers connected, at about 1 meter, at listening height, and looking for overall crossover integration from 200Hz through 20kHz; room position not optimized for LF, and using a moderately long impulse window with a Hamming impulse filter.

This was actually a bit better than I expected for first time, as regards level matching- no immediate tweaking indicated!

Well, lets see how noisy and crappy it looks with a really long impulse window and a 3m test distance... and only 1/48th octave smoothing (which means, essentially no smoothing)

This highlights why both room positioning and treatments are important, but on the other hand, the overall extension and response is in the ballpark of what I expected for this first test with the new crossovers.

Listening to some cuts from the original Nickel Creek album brought some smiles to me...

Well, while formatting this data and uploading, I've been also listening also to another Nickel Creek album, "A Dotted Line", which I like to jokingly refer to as my favorite heavy metal bluegrass album. It DOES rock more in places than some of their other releases. I'm working and listening in the "computer den" which has double doors, but one one opened right now, and I'm at 90 degrees off axis, so in here I'm mostly getting the reflected power response- but note that if I walk in a wide arc in front of the test speaker, the tonality is very uniform, due to the previously documented excellent dispersion of the MF and HF drivers. And it sounds better than it has any right to off in the computer den.

Next steps-

clear away the assembly cart, optimize room placement a bit and probably bring in some of my ATS panels
Look at whether any additional damping in cabinet may be desirable.
Construct the auxiliary rear firing tweeter crossover and system, and test (GRS RT1.0-8)
Burn in the system, and get better LF measurements
Listen to a bunch more albums, with the demo music cart, not the test cart!

**JonMarsh** · 16 December 2024, 19:19 Monday

The remastered Linda Ronstadt "Heat like a Wheel" is really nice on the vocals, even just one channel!

**letiennam** · 16 December 2024, 22:21 Monday

In recent days, I have been re-reading the first posts to slowly implement this project. Especially the PT2252C mod. I bought 3 pairs mainly because of durability concerns. PT5010 will be reserved when my account balance is greater.

**JonMarsh** · 17 December 2024, 09:34 Tuesday

Check out the most recent postings, regarding the MOD 300 series for PT2522c, last versions using Acoustastuff as the damping material, and 1/4" phenolic to fabricate the rear enclosure.

Recommended overview include posts 206, 207, 212, 213, 214, and 251.

**technodanvan** · 19 December 2024, 17:23 Thursday

Looks like you need to make another one of these soon Jon, lest you get an obsession for listening in mono!

**JonMarsh** · 20 December 2024, 09:39 Friday

Very true- but what's worse than mono is just one channel of Stereo! which is all I've been able to listen to!

A key issue with that goal (2nd speaker) is that though I have all the subassembly pieces cut, and an earlier version of the upper module built, temperatures in the garage are too nippy for gluing work. See, that gazebo project put me about six weeks behind on everything else.

Now, while that is one factor, another is my current review of the LF alignment, and discovering some disparities between measurements and past design synthesis using Unibox and Dayton Data. I started making progress on that when I did an enclosure evaluation in VituixCAD, using the driver data in Kimmo's database, which is NOT identical to the factory data. Then, too, there seem to be some differences in how the calculations work between Unibox and VituixCAD- I've seen this previously with "difficult" drivers from Peerless, like the STW350F, or the SBS160.

This plot from VituixCAD is much closer to measured reality than Unibox3 or Unibox4.08, the last version. This is a shame, because I like the working format and graphs in Unibox.

I've also done some more measurements with and without the LF Crossover, and see some areas that I need to investigate and adjust.

This is why I always refer to what I've been sharing as WIP.

Note, I'll also be making an adapter plate and finishing the build and tweaks for the crossover for the MOD300 PT2522c.

Of course, the seasonal distractions don't help my "work efficiency", but then, at least it looks for now like we wont' be going to Bainbridge WA for Xmas to visit with wife's younger daughter's family. There's a bit of a story behind that, relating to last year, but I'm not going in to that!

I'm just trying to go for progress every day...

**JonMarsh** · 20 December 2024, 09:44 Friday

One more thing- a disturbing note is that VituixCAD indicates a more ideal extension and leveling of response is possible with a 150L enclosure. So, I may be trying a rather more larger cabinet build, also. For now, I'm investigating optimizing the existing build, as regards leveling the response being priority #1.

.

**technodanvan** · 20 December 2024, 10:10 Friday

What's an extra 60L between friends?

**JonMarsh** · 20 December 2024, 16:34 Friday

Between friends like us, te nada! But between mere acquaintances, it could be a problem!

And then again, 60L is the entire volume of a Wavecor Ardent!

**theSven** · 21 December 2024, 15:50 Saturday

I'm glad I've been waiting patiently on the sidelines for this project as it progresses. Patience is finally paying off for me 🤣.

**JonMarsh** · 21 December 2024, 17:39 Saturday

Originally posted by theSven

I'm glad I've been waiting patiently on the sidelines for this project as it progresses. Patience is finally paying off for me 🤣.

well, with a kind thought like that this Saturday, I think I should reward you with some more information, though whether it will generate insights remains to be seen!

This is just about interesting "peripheral" measurements that sometimes don't get the attention they should- in this case, it's about tweaks and optimizations for the LCR zobel impedance stabilization network, a bit about how that pays benefits overall, plus some ongoing tweaks to the crossover.

LF crossovers in a three way are more challenging the lower the crossover frequency is, because of the interaction of the crossover components with the very variable by frequency driver impedance. This is especially the case for base reflex or passive radiator system, due to their dual peak impedance curves, with the peaks straddling the tuning frequency of the Helmholtz system (box Fb, in more modern terms).

First, I'm going to plot the impedance for the system, then the individual crossover gain plots for each section, WITHOUT the LCR zobel network in place.

Here, you can see the double peaks of the woofer plus Passive radiator LF element, with an FB tuning at about 27Hz. This is the box Fb, and approximately the frequency where the woofer and passive radiator are working together most completely, with minimum excursion of the woofer. Note the system impedance is at a minimum between roughly 80Hz and 105 Hz, corresponding to the impedance minima of the woofers, but due to the interaction and current phase in the crossover network, the actual impedance is LOWER than that of the woofers. This is pretty common in a lot of speakers- go look at plots of Avalon or say, this Magico A5 as tested by Stereophile Magazine.

For this analysis above, you can see the current phase dips to - 60 degrees at about 48Hz.

The Magico production speaker drips to about -67 degrees, also just above 50Hz, and between around 80Hz at 160Hz, the impedance is around 2.5 ohms. Better not try an HT amplifier with this puppy!

These impedance interactions have effects on the low pass filter that would not be expected going into a resistive load- here you can see the result for the SMJ-40/Saint-Säens without the LCR zobel filter, in the red LF plot trace on the left:

Now, with the previous version of crossover filter and zobel network, prior to additional measurements and optimizations, we have these results:

"Just" a 1 dB bump centered at 50Hz...

And the peaks and range of the bass dip impedance are reduced, but still not really optimum... of course, my Halcro's or Cambridge Audio Edge W's would shrug it off...

With the V3 update below, well, some things get a wee bit pricier, but your amplifier won't have to, as long as it's not too uncomfortable with 3 ohms with a very benign current phase...

And the filter behavior is on target without any significant funny bumps...

Non-junkbin parts on order for the updates. New layout drawings in progress. And a small tweak under consideration to the midrange crossover, too.

Ho Ho Ho, Merry Saturday!

**JonMarsh** · 22 December 2024, 10:14 Sunday

After posting yesterday, I got to thinking about the data discrepancy for the RSS210HF-4 and wondering if this was the case with the RSS210HO-4 also.

Unlike the RSS210HF-4, VituixCAD T/S data and the Dayton data sheet for the RSS210HO-4 agree. And in this case, both Unibox4.08 and VituixCAD agree that the RSS210HO-4 and my "classic" configuration of 350g Mms PRs (either RSS265-PR or the SL26R) will work pretty well in even just 80-90L of net enclosure volume.

How well?

About this well... at 2.83VRMS drive (1W at 8 ohms, 2W at 4. Note the HO impedance is about 10% higher than the HF version)

And if you want to push them, say, 50W each...

you're looking at 110 dB, with plenty of headroom for the excursion.

Hmmm, started checking for spare change under the sofa (usually not much this time of year!), but now have 4 on order, should get here Jan 2.

Cross fingers...

**technodanvan** · 22 December 2024, 11:36 Sunday

Uh, my wife has indicated that I must use the -HF variant lest I suddenly have a bunch on hand with no purpose.

Edit: I'm not sure why I have 12+ actually. Maybe for the MTM you had posited a while back with the Peerless corundum tweeter?

**JonMarsh** · 22 December 2024, 16:23 Sunday

That is between you and your wife, Danny... and yes, I haven't dropped consideration of the HF in an Ardent like design, on a relative budget. I have 10 RSS210HF-4 here... and one completed 100L cabinet, and all the subassembly parts to put one more together. And I have 4 RSS210H0-4 ordered for evaluation, first in my single driver + PR cabinet, should be here right after New Years.

As usual, WIP, slow work takes time...

And Happy Holidays!

**letiennam** · 22 December 2024, 23:01 Sunday

Originally posted by JonMarsh

One more thing- a disturbing note is that VituixCAD indicates a more ideal extension and leveling of response is possible with a 150L enclosure. So, I may be trying a rather more larger cabinet build, also. For now, I'm investigating optimizing the existing build, as regards leveling the response being priority #1.

.

I'm also really looking forward to the HF optimization going well, and being successful. I'm also willing to be patient and wait as a gift for the New Year. my idea of adding 60l is to increase the height of the module for the woofers.

And Happy Holidays!

**letiennam** · 22 December 2024, 23:51 Sunday

Originally posted by technodanvan

Uh, my wife has indicated that I must use the -HF variant lest I suddenly have a bunch on hand with no purpose.

Edit: I'm not sure why I have 12+ actually. Maybe for the MTM you had posited a while back with the Peerless corundum tweeter?

Women are so alike. So did my wife, but I was patient and didn't make a box for the 4 HF series woofers yet. However i have bought all the components for the crossover. Anyway i really admire sir Jon for his perfectionism and contributions. I have never stopped looking forward to the completion of this project.

**technodanvan** · 23 December 2024, 09:03 Monday

Haha, I'm kinda speaking for her in this instance. I'm sure I could manage to grab the -HOs if it came to that, but I'm not sure the additional extension is super worth it for the extra cab space. I'm very interested in Jon's findings though, regardless of how it turns out!

**JonMarsh** · 02 January 2025, 21:00 Thursday

Slow work takes time is how shipping works this time of year with the holidays interspersed!

But it's HO HO HO here late today...

Testing tomorrow! (didn't get here until after 6 PM! Poor UPS guy- miserable weather today!)

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

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