A New Adventure

[Steve Manning]

So, now were getting to the punch line of the story. As most of you have guessed we have started an official business with the name of SMJ Audio. There is a website under development and will go live soon.
As Jon alluded to earlier, we are working on a number of ideas which include complete speaker designs, customizable cabinet designs and waveguide concepts. Once I can pry Jon from his day job, not an easy feat these days, he’ll give some more detail on the arcs and sparks side of things. We are presently working on an MT design that will showcase a number of the things we’ve been working on, more on that shortly.

At this point in time, I’m offering design and fabrication services for who ever needs them. If you don’t have the tools, time, experience, or need something completely custom, I can help make it happen. A good example would be Ardent baffles. Last year I built two sets for forum members and that was before the shop upgrade. It can be anything from getting your ideas into a CAD drawing so you can visualize what you have in mind. All the way up to a turn key set of speakers if you just don’t want to mess with any of it and don’t want to pay the boutique prices of buying something commercial. I can also help you out if you want a custom equipment rack for your electronics, those seem to be an after thought for most of us.

By the way, here's a few pictures of the second set of Ardent baffles that I did. These will have grills (dog slobber protectors, is my understanding). The grills are attached with hidden magnets.

[CADman_ks]

This is really awesome!!

I recently bought a knock-down kit from Parts Express for a sub. It was part of a deal, and at the end of the day, I wanted to try a kit to see what that was about.

I was very impressed with how it all went together, and I'm sure that yours will have the same attention to detail. It may have actually spoiled me from making boxes in the future!!

[technodanvan]

By the way, here's a few pictures of the second set of Ardent baffles that I did. These will have grills (dog slobber protectors, is my understanding). The grills are attached with hidden magnets.

Hey, those look familiar! Once you have a Newfie you kind of start expecting the drool to end up everywhere - including the ceiling. Considering making some large vinyl covers to put over these once complete...just in case.

How does one upload images here? Need Photo-bucket, Imgur, or something instead of Google?



If you look close you'll see those very same baffles...


Steve and Jon - very much looking forward to seeing what you have planned!

Steve - Would you be interested in making some prettier baffles for a set of Dayton 0.25 curved cabinets? I could send one of the cabs and a woofer/tweeter to you for accurate measurements if you need them.

[Steve Manning]

Hey, those look familiar! Once you have a Newfie you kind of start expecting the drool to end up everywhere - including the ceiling. Considering making some large vinyl covers to put over these once complete...just in case.

How does one upload images here? Need Photo-bucket, Imgur, or something instead of Google?



If you look close you'll see those very same baffles...


Steve and Jon - very much looking forward to seeing what you have planned!

Steve - Would you be interested in making some prettier baffles for a set of Dayton 0.25 curved cabinets? I could send one of the cabs and a woofer/tweeter to you for accurate measurements if you need them.

That's a big boy you've got there Danny.

Loved to on the baffles. Email me and we can work out the details.

[Steve Manning]

So, a little more info on this MT design we have been talking about. Well Jon sends me a link asking me what I thought about a speaker that he and a friend had auditioned on a trip to Germany a few years ago. Though they thought the cabinets were great, the sound was lacking, especially for the $264K asking price. Of course, there was the wouldn’t it be great to make our own conversation but make it sound better. Of course, that’s when the mayhem began. Doing a little digging into the company we found that they make a full range of this style speaker.

[cochinada]

Funny you mentioned this because it was this exact model that motivated me to make my current one.

[Steve Manning]

Funny you mentioned this because it was this exact model that motivated me to make my current one.

Joaquim, that is funny, very appropriate as well. Some of the issues you had with your build as well as those others of us have had, were part of the design considerations for the path we took with what we have come up with.

[cochinada]

Steve, are you guys also considering using some kind of elastic membrane in between the main material layers to avoid those nasty issues with the translam buiilds?

[ergo]

I was thinking about the same questions. Seems like this type of build would need each layer/ring to be painted before assembly... or if after then getting the gaps sanded and painted with different shade must be a serious hassle. Adding a thinner layer of 'other material' in between might make it easier indeed and potentially acoustically damped.

Anyhow, a pretty cool look on those speakers, but a serious technical challenge for sure.

[JonMarsh]

Well, this is all a good lead in to a discussion about materials capabilities and construction and assembly techniques that have been developed, but I will not steal Steve's thunder on this one just because I type faster than he does...

While this has been a collaborative effort as regards first level concepts and principles and goals, Steve is the detail and heavy lifting guy on the ME end of this, just as I am the wires and sparks grunt. And yeah, I'm sitting on a huge pile of CAD renders and drawings and photographs to boot, but this is Steve's story to tell at this point....

[Steve Manning]

You mean a thin layer that looks something like this.

[ergo]

very much like that yes - neoprene rubber or such would be cool, but DIY cutting that is probably a pain + it's not gonna be very cost effective as there is a lot of waste material.... though I guess you could buy a knife cutter head for your CNC

[Steve Manning]

Here are a few more renderings of what the initial MT will look like.

[Steve Manning]

Steve, are you guys also considering using some kind of elastic membrane in between the main material layers to avoid those nasty issues with the translam buiilds?

Sort of ..... There is what we are calling a spacer that will go between each "rib" layer. The material I have chosen is compromise of a number of factors. Cost and actually being able to make/cut the material we selected being two major ones. You think lbl is expensive, try looking at flexible plastic!

[Steve Manning]

I was thinking about the same questions. Seems like this type of build would need each layer/ring to be painted before assembly... or if after then getting the gaps sanded and painted with different shade must be a serious hassle. Adding a thinner layer of 'other material' in between might make it easier indeed and potentially acoustically damped.

Anyhow, a pretty cool look on those speakers, but a serious technical challenge for sure.

Yep, paint first then a put all the parts together. By the way we are looking at going with mdf, BB and lbl options, so a painted look is not he only way to go.

As to the technical challenges .... this is something I've been mulling over in the back of my mind for a long time. Jon sending that link added a few more pieces to the puzzle and I think we have come up with a nice solution.

[Steve Manning]

To continue from earlier, what we liked was the modular approach of the cabinets, which inspired us to look at making a possible series of speakers in different sizes, as well as modules that could be combined to improve the performance of a system over time. It also appealed to me since I’m a bit of a fan of translam designs as well as curved sides. With regard to the translam idea, this derivation of it, eliminates some of the inherent problems of that type of construction while adding some advantages.
So, with considerable time spent working on drawings and researching fabrications options, we have come up with what we feel is a unique option for you DIY enthusiasts for making cabinets.

To break the renderings down a little, a group of standard parts was developed to pick and choose from to make a cabinet of your desired volume and features.










This design also gives a unique option in that if at some point you want to turn your MT into an MTM you don't have to build/buy an entirely new cabinet. You just buy the additional parts to increase the volume and away you go.

[Steve Manning]

Just to show this has progressed well beyond the pretty picture stage ...... Parts have been machined to make a full pair of speakers.








By the way this CNC with a 1/2" diameter bit can churn out a boat load of dust. As I recall that's a 30 gallon bin for the dust collector.




Checking fit up.

[Steve Manning]

A few more ..... This is a 1 cu ft cabinet, net volume. There will be a 7.5" woofer and tweeter for the music part.











This is what we are calling our small size cabinet, where a 7.5" driver is the largest it will handle. The mama bear size will handle up to ~10" and the large up to ~13" drivers.

Again, you can make the volume what ever size you need to match design requirements.

[cochinada]

Very nice! :T
I have a question though: I see you are using rods to assemble the cabinet. Aren't you afraid this might prevent or constrain the layers from moving or are you confident the plastic will eliminate all potential problems?
There is a thread in another forum of a guy that built a huge translam array where he used rods but didn't have plastic in between. I'm sure you saw it as he's a perfectionist like you. He faced the same issues most of all had and I remember there was an endless debate about it. I think he's also in this forum but I don't have the link at hand.

[Steve Manning]

Very nice! :T
I have a question though: I see you are using rods to assemble the cabinet. Aren't you afraid this might prevent or constrain the layers from moving or are you confident the plastic will eliminate all potential problems?
There is a thread in another forum of a guy that built a huge translam array where he used rods but didn't have plastic in between. I'm sure you saw it as he's a perfectionist like you. He faced the same issues most of all had and I remember there was an endless debate about it. I think he's also in this forum but I don't have the link at hand.

Thanks ..... I want to say that I did see it and a I recall the rods just aligned things but he ended up still "hard" mounting/gluing things ..... I could be wrong on that. Nothing here is hard mounted, including the baffles. They are bolted in place with a gasket between it and the cabinets. There is also a non permanent rubber coating on each side of the spacers for sealing, so I don't expect to see any issues with materials splitting like most of us have had in the past.

[JonMarsh]

When you get right down to it, what we see is a conceptual balancing act- trying to use the materials in the most favorable way. Many materials have desirable characteristics with one type of stress, but not with another.. one can just brute force the whole thing (think Rockport and Magico for example, as well as Wilson and YG Acoustics. Tidal Acoustics, check, mostly more of the same. Damn straight it works, but boy is it heavy and expensive.

Now, I may be one of the poster children around here for heavy and expensive... guilty as charged. Most of you guys won't remember my X1 SLAMM Klones... but many of you will remember these, prior to final coats and polishing, made completely of 1-1.25" maple ply normal used for piano pin block construction- stuff that makes BB ply look like laminated balsa wood.



These are parked in climate controlled storage in Idaho, and will start getting some attention again in 2021.

While I wouldn't quite call what we're trying to do now pushing the "reset" button, it did seem like maybe it was time to take another look at different "best practices" for putting cabinets together.

Translam construction is something that's attracted many DIY guys, due to the freedom of form and the possibility of getting something that DOESN'T look like other box... but as Steve and Joachim and many others know, it's like Willie the Shake said, "Many a slip twixt the cup and the lip..."

Obviously it's a bit early to start breaking out the champaign or anything... but I've got a good feeling about this.

A Danish guy that I used to work with (much younger than Moi) until he found his dream job back in Southern CA in 2017, was just as into pithy sayings as I have a weakness for. Stuff like "In God we Trust, all others we verify", and "Steal from the best, and ignore the rest..."

I visited Gauder Akustik's main dealer in Muenchen (Munich to you Anglo boys) back in 2016... it was one of the darnedest experience I've ever had... The cabinets were clearly very well built, quite dead, and of course they were loaded with all these beautiful Accuton drivers... though in some cases I suspect not the RIGHT Accuton drivers... (if you wonder what I mean, go look at the distortion profiles for ALL of their various 7" drivers, and then come back and check and see which ones I use...)

Problem was, there was a lot of highs, a lot of lows, a lot of midrange, and it didn't really fit together all that well, and I have a set of desktop speakers (IK Multimedia iLoud Micro Monitors) that image much better than them... (recommended them to Steve and he was very impressed with the imaging)

At the time, it was just a mystery to me and my local colleague that had found the dealer and who had high hopes also, to replace his Eggleston Andra's. That didn't happen.


Well, some follow up research well after the trip revealed information about the crossover types and design- they use an elliptic filter with very high slopes (and high attendant group delay). In all fairness, been there, done that, have the movie and residual video rights, but my dissatisfaction with it lead to the special 3rd order -6dB at crossover filter that "debuted" in the NatalieP (in a series connection form) and has been used many times since, including the Isiris and Wavecor Ardent (the first Ardent used a Duelund transfer function design).

But what I liked about the cabinet concept (besides the esthetics, which is after-all, obviously a personal preference issue) is basically using materials where they are good at what they do...

Mmmm....

• MDF: Good compression strength, relatively inert and self damping- and fairly inexpensive for good cabinet grades (no, we're not talking HD here...)
• Metal rods- usually very good tensile strength, but in thin rods, not so great at bending forces; think bolting down the heads on your motorcycle or car engine...
• Compression gasket: now just what does that mean, exactly? What it needs to do is be able to handle compression forces in stable manner, form the basis for sealing the ribs together, and if there is a bit more damping of the overall structure as a result, well that would be a good deal, too! Any gear head is familiar with the idea of a compression gasket...

As Steve points out, we liked the idea of this system because of the possibilities for mix and match- how many X brace sections do you want? Do you want an acoustic divider plate between different vertical sections? do you want to experiment, bolt up and test a few configurations, then put your final choice together with panels and damping material tuned to perfection?

Maybe it's too many choices.

But I think not.

So, let's not get carried away... this is a work in progress, but it definitely is making progress. I'd say we could have stuck with some of the driver's I've used before, but we're trying some new stuff, there, too, and we'll just have to see if it works out- it's one thing to measure individual drivers and ooh and ahh about distortion and SPL plots, but it's putting it all together into a coherent result that is the challenge- and the approach for this one is intended to be a "interesting" combination of value and performance (we hope). (Should any of this "hiccup", I will of course disavow all knowledge and responsibility, and claim that ET made me do it...)

And as I mentioned somewhere a while ago, a first test crossover is going together... but I have to admit the shape of the crossover board is a bit more of a challenge!

[ergo]

Very cool progress and a nice concept for modularity indeed

Milling processes can create a lot of dust. I'm wondering though why you use 1/2" diameter bit. Does it allow faster speed? It should not be cheaper... My main driver for that type of work is a CMT 6mm bit which is close to 1/4'', so would make 2x less dust
Anyhow, I'll be asking you after you've run a punch of these on what are the good bits and also feeds and speeds. Improving the know how on that front can always help.


Another question that's hard to guess from pics is how do you start and end the threaded rods. I mean the fastening/nut seems hidden on both ends? If the nut is hidden then do the last layers attach with glue and rest are hold together with the rods?

A question for Jon also... I saw a WG milling attempt few pages back, but this unit seems to use the regular tweeter... Will there be a WG powered version as well later?

[JonMarsh]

A question for Jon also... I saw a WG milling attempt few pages back, but this unit seems to use the regular tweeter... Will there be a WG powered version as well later?

There's no reason for there not to be; I think something important to keep in mind is that this is like a proof of concept execution exercise for us- running down a lot of different issues and processes to make this happen.

It's not like the world needs another 6-1/2" two way, as people are fond of saying (of course, we're sort of circumventing that by doing a 7.5" two way!). It's not that we see this as a reference design per se, but more a vehicle for testing out all the concepts and seeing if it really does all come together the way we home and expect...

While I think we'll wind up doing several design examples, for which we can kit up most or all of the parts at attractive prices (Steve has been a busy boy on the business end of this), we also see this from the DIY perspective as an experiment to see if there is interest in a flexible and modular system for putting together your own high quality cabinets and designs without having a full blown wood shop. In fact, all you might need is some room in a spare bedroom and a soldering iron and small drill (maybe not even that). Now, one thing Steve could do is a full blown cabinet set to spec. All finished and ready to rock and roll. Another option is just providing the CNC pieces in your preferred material depending on taste and budget.

On the other hand, we most definitely do want to pursue the waveguide options, and have some made, and I've been doing testing. Finishing the first MT design and finding out through the process if there are any unexpected "issues" is top priority for now.

We had a really nice waveguide that worked beautifully with the original RS28a... until they discontinued it the next month. (that might give you a notion of how long some of this has been kicking around.)

With Steve's setup it's fairly easy to get ones done for the dimensions of a specific tweeter, but still we find that some tweeters are more amenable to this approach than others.

And interesting thing to consider also with a waveguide is 2.5 ways, and particular, I've been looking at and modeling some concepts for asymmetric 2.4 ways- different full low range and low range fill drivers. Troels I notice has done some of that, too, lately. I have two concepts already in the modeling stage and with most drivers on hand- just got a shipment notice from Canadian post, so one I've been waiting on will be here soon.

And speaking of things from Canada, I do have two replacement pairs of the BlieSMa tweeters now- one aluminum and one Be.

ET is looking at some low dollar possibilities in the waveguide area, for his "Tiny Technological Terrors", and there is one promising concept, that though it is something of a PITA to put together is very high value for the performance you wind up with... and by that I mean distortion, too- but we need to finish construction of a pair and audition and critique complete setups before offering "suggested configurations". There's three different configurations of that under consideration... (don't let ET know that I leaked this info on his projects here... but I've seen documents and files about a "Modula JM", a "Modula PL", and a Darth Modula- rumor is the PL stands for "Padawan Learner" and JM, well, I'm sure you can figure that out.)

At this time the Tiny Technological Terrors are being tested with some PE Denovo enclosures... they could be done with the translam setup, too, but it seems like having some lower cost newer tricks up the sleeve akin to the Modula's and NatalieP's of old might be handy... but with updated driver technology and lessons learned over the years.

Think of them as a possible gateway drug to the bigger stuff...

[Steve Manning]

Very cool progress and a nice concept for modularity indeed

Milling processes can create a lot of dust. I'm wondering though why you use 1/2" diameter bit. Does it allow faster speed? It should not be cheaper... My main driver for that type of work is a CMT 6mm bit which is close to 1/4'', so would make 2x less dust
Anyhow, I'll be asking you after you've run a punch of these on what are the good bits and also feeds and speeds. Improving the know how on that front can always help.
[ATTACH=CONFIG]29362[/ATTACH]

Another question that's hard to guess from pics is how do you start and end the threaded rods. I mean the fastening/nut seems hidden on both ends? If the nut is hidden then do the last layers attach with glue and rest are hold together with the rods?

A question for Jon also... I saw a WG milling attempt few pages back, but this unit seems to use the regular tweeter... Will there be a WG powered version as well later?

The main reason for going with the 1/2" bit is cutting length. The "ribs" that make up the cabinet are 1.5" thick, that pretty much rules out 1/4" bits right off the bat and even 3/8" if you want to make sure you have enough clearance to the bottom of the spindle. Since I'm very much in the learning mode with the CNC I'm being conservative. At present I'm doing a .55" depth of cut at a feed rate of 225 IPM. The machine will do over 400 IPM but for now that's where I'm at.

As for the threaded rods ..... can you say threaded inserts in strategic locations. Lock nuts are used on the bottom side and are hidden in recessed pockets. The very bottom of the cabinet is more of a cosmetic cap.

[Browncoat]

Sweet shop. Nordfab ducting? I'm jelly.

I'm not a woodworking expert, but I think plywood laminations are risky for big projects. Doesn't wood move mainly perpendicular to the grain? If so, it moves mainly in width and thickness, and usually thickness is a small enough dimension that it can be ignored. However, build up enough thickness and movement becomes non-trivial. At least from a woodworking standpoint, I like the MDF idea better

[Steve Manning]

Sweet shop. Nordfab ducting? I'm jelly.

I'm not a woodworking expert, but I think plywood laminations are risky for big projects. Doesn't wood move mainly perpendicular to the grain? If so, it moves mainly in width and thickness, and usually thickness is a small enough dimension that it can be ignored. However, build up enough thickness and movement becomes non-trivial. At least from a woodworking standpoint, I like the MDF idea better

Thanks Browncoat ..... yeah, it was a little more of a splurge for the Nordfab, but the flexibility of the system and time saved was worth it.

As far as things go I'm certainly not an expert either. As far as movement a lot depends on how the log/wood is cut, as well as the humidity in your home over the year and all that fun stuff, so if your weather is all over the place, like where I live, it can be an issue.

Typically it will move with the grain, which is across the width of a board. Now if you can get a board that has been quartersawn it's very stable across the board because the grain lines run into the board. Plywoods are pretty stable across the sheet but they will expand across the thickness as a number of us have found out with Baltic birch. If you constrain it by doing something like gluing a baffle in place you can have a real issue.

All of this has led us to going with the design we have been talking about and not gluing up all of those layers in the first place.

[JonMarsh]

I mentioned some WIP (work in progress) - I'd expected this crossover test board to be done by now, but some of the wiring I ordered won't be here until May 31. Gives you an idea of how we're approaching this. This is what I'd call mid/upper range implementation of the crossover- Lumen tweeter caps and other fairly good parts, but Mills, not Mundorf 20W resistors as used in the Isiris and Ardent.

There can be a huge range of cost for the crossover just based on how fancy-dancy you want to get with components... I can explain all the choices so far, if desired, but in the end it does come down to personal preference and budget. We're not trying to make this MT "demonstrator" an all out assault on the concept of 7" two ways, but do want it to be musical and transparent within the capable operating range.

With the electronics I use, that means going for somewhat pricey tweeter caps, as my consistent experience is that this pays off with good associated equipment. The Janzten Lumen caps are one of the best price/performance tradeoff parts I've found. If you're curious about evaluations for capacitor "sound and impact" in crossovers, check out Humble Homemade Hifi (Tony Gee's site) with his capacitor review section- for the ones I've evaluated personally, my subjective impressions are similar to his. If you've got bucks to burn, then Clarity CMR are very good, and Duelund in various forms even better... but definitely at a price.

My suggestion would be if one was to be building this design once it's finished, consider the end use- as HT mains or Satellites in a dedicated home theater, Dayton Audio PP might be just fine, and save big bucks. If you have a nice DAC, and particularly if you have one of the R2R ladder DACs on the market these days, OR if you have or plan a vinyl rig in your future, consider using upgraded tweeter caps.

An interesting question as always is how expensive/good of a tweeter do you need to justify that?

The funny thing is, that I was remarking to Steve this week, is that it seems like I can do a tweeter just just listening to the swept sine chirp and tell you out of 3-6 tweeters which one is the best (without cheating and looking at the results in Fuzzmeaure) and I did that this week one some waveguide tests I was running- and the least expensive tweeter, which is the one being used for this MT, was the winner. Due diligence can be expensive to perform, but it certainly does contribute to life's useful lessons.





And just to take a bit of the suspense out of this Sunday tease fest on my part, this is the Satori woofer for this system, arrived at after testing quite a few drivers:

[JonMarsh]

Last week was one of those weeks that felt like trying to wade quickly through cold molasses... and then you step into an unexpected sinkhole!


The sink hole was my 15 year old ACO Pacific mic and preamp developing an output offset and noise, couple with a LF roll off- out of action. I contacted the vendor/Mfr. here in the Bay Area, and got a new one on order... which did arrive today. But that has set some things definitely behind schedule... I'd figured to maybe have a little spare time for this on the Memorial Day weekend, and that didn't work out either.


So, just be advised, I think there might be a chance Steve will just convert this to a speaker stand making outfit, based on the latest renders he sent to me... do you think this is a hint?


I tried to explain things to Steve today... not sure it went all that well...

https://youtu.be/JFvujknrBuE

But Steve's stand renders look pretty righteous to me...












And what Steve can render, Steve can build... this we know.

[ergo]

A nice looking and technically very nicely though out stand. I assume the spacer lines are the same plastic material as the main speakers?
Making that very shallow chamfer is something that makes me scratch the head. With hand-held router It would be hard to find a bit like that. Table saw is also out as the shape is not straight lines.... so I'll be following with interest on what magic makes those happen

[Steve Manning]

Thanks Ergo .... yep, same material for consistency.

Your right about the shallow chamfer being a bit of a pain. The way I see it, is I have two options if I want that look. Do it on the CNC and a first stab at programming the profile, it looks to be ~20 minutes machine time for each piece. The other is buy one of these, https://www.toolstoday.com/v-5840-49416.html and be done with it. It's certainly not the cheapest bit, but time wise it could be the way to go.

[technodanvan]

Thanks Ergo .... yep, same material for consistency.

Your right about the shallow chamfer being a bit of a pain. The way I see it, is I have two options if I want that look. Do it on the CNC and a first stab at programming the profile, it looks to be ~20 minutes machine time for each piece. The other is buy one of these, https://www.toolstoday.com/v-5840-49416.html and be done with it. It's certainly not the cheapest bit, but time wise it could be the way to go.

I would think the bit would be the way to go, you could even do a real basic 'stepping' on the CNC to remove some material, making it faster on the router/shaper afterward. Might also help the bit last a bit longer.

[ergo]

Thanks for the link to Toolstoday Steve. They ship to EU as well, so I might consider them at some point.

I agree with technodanvan, that the hybrid method is probably the fastest and saves the big cutter from very hard work.

[CADman_ks]

I would agree that the bit would be the faster, and easier way to do that.

For us hobbyists that don't want to spend an arm and a leg on a bit, there's these as well:

https://www.amazon.com/Yonico-Degree-Forming-Router-2-Inch/dp/B07GZW5VCQ/ref=sr_1_3?keywords=60+degree+router+bit&qid=1559659346&s=gateway&sr=8-3

I've actually bought some of these Yonico bits for rabbits and roundovers (big ones), and I have been very pleased with the performance vs. the price.

If I was doing it for a living, I might be a little bit more inclined to go the Amana route, however...

Just an option...

[CADman_ks]

This one is only 15 degrees, but you would be limited on depth, unless you got a bigger bearing for it:

https://www.amazon.com/Yonico-2-Inch-Diameter-Raised-Router/dp/B07FTTZNJK

Other options are out there, some even at an affordable price for hobbyists...

[Steve Manning]

I would agree that the bit would be the faster, and easier way to do that.

For us hobbyists that don't want to spend an arm and a leg on a bit, there's these as well:

https://www.amazon.com/Yonico-Degree-Forming-Router-2-Inch/dp/B07GZW5VCQ/ref=sr_1_3?keywords=60+degree+router+bit&qid=1559659346&s=gateway&sr=8-3

I've actually bought some of these Yonico bits for rabbits and roundovers (big ones), and I have been very pleased with the performance vs. the price.

If I was doing it for a living, I might be a little bit more inclined to go the Amana route, however...

Just an option...

Thanks for the links CADman ...... I had not heard of these before.

[CADman_ks]

Glad I could offer some assistance!!

Again, for me, they have been more than satisfactory bits, but I haven't used mine a LOT, so I don't know what the long term reliability of them is.

Might not hurt for you to try one, and see how long they last. At any rate, you're not out a lot of money to try on...

[Steve Manning]

Glad I could offer some assistance!!

Again, for me, they have been more than satisfactory bits, but I haven't used mine a LOT, so I don't know what the long term reliability of them is.

Might not hurt for you to try one, and see how long they last. At any rate, you're not out a lot of money to try on...

The only thing that sucks is the UPS man is delivering one of the Amana's today. What can you do, chances are I'll be using it for a long time to come. I had checked MLCS first, I use them for cheaper bits that I don't expect to use a lot, but they did not carry the steep angles like that.

[CADman_ks]

You'll definitely end up with a good bit in the end, though!

Happy sawdusting!!!

[JonMarsh]

Well, all this router bit business is very interesting, I suppose, but I have my 60 degree bits for some time... and besides, I'm more the wires and sparks kind of guy, though I can avoid hurting myself around a big table saw or 3-1/2 HP router...

Speaking of wires and sparks... in the end, it's all about the SPL's...


So, having measured drivers in some test cabinets that have the right overall baffle width, and having built a test crossover to evaluate whether the demo concept will work, well, of course the next step is to test the crossover with the drivers in their somewhat non-optimum but quickly built cabinets...

By non-optimum cabinets, I mean some Denovo knock down kits that you can throw together with nothing more elaborate than a few clamps and some glue or epoxy...

If dress for success applies DIY, no one is going to be impressed....



Only the top two cabinets are involved - the others are just a "stand" for setting up the test. Also, the MW19P Satori is just sealed; we have a sort of trick ported arrangement to try out, but haven't gotten farther than just modeling it.




Here we have the crossover, built to the target form factor to see how comfortable it might be- lots of room on the board, actually. It's a mix of what I would call "upper mid Fi components" along with some better than average tweeter caps (Jantzen Lumen capacitors- pretty transparent sounding but without any glare or etch to speak of).




With the drivers spread so far apart in this test setup vertically it's a relatively narrow window in the crossover transition region, but it wasn't hard to find... in fact, pretty much exactly where it ought to be!



This crossover does incorporate the voicing concept with a gradual 1-1/2 to 1-3/4 dB roll off above 1kHz. There are some other tricks, too... but we can only see if they work fully looking at the distortion plot...





My initial reaction is that mission appears to be accomplished from that perspective- I was shooting for an Ardent like distortion characteristic, trying to keep HD2 down as well as HD3. This was measured at 2.8VRMS.

All I can do for the moment is listen to it in "glorious mono" using VOX on my 2014 MacBook Pro used for testing drivers and speakers. Not state of the art, though the Cambridge preamp and Aragon amp are pretty decent for the day and age.

Test cuts include Sting, Cuandero, Howard Jones, Edie Brickell, Maire Brennan, Poor Claires, Fourplay, Spyro Gyra, Jacque Loussier Trio, Daria, Alice Gomez, Steely Dan, etc.

I didn't have time to do off axis checks with the full setup, but a quick walk around with various program material shows the tweeter living up to expectations based on the raw the measurements in the same test setup. Excellent subjective behavior out to 60 degrees off axis. Probably the best $300 tweeter $50 bucks can buy...

[Zvu]

Great stuff Jon.

About the crossover, i'd put something beneath it if the shelf is made out of metal so it doesn't mess up the values of coils.

[Dave Bullet]

Jon which tweeter are you using? Sorry if you posted above but I can't find it. Or is it something special that only ET can source?

[JonMarsh]

Great stuff Jon.

About the crossover, i'd put something beneath it if the shelf is made out of metal so it doesn't mess up the values of coils.

Good point to bring up, but the shelf is just fancy duded up HDF. The crossover base is phenolic, fairly thick, from Leecraft.

[JonMarsh]

Jon which tweeter are you using? Sorry if you posted above but I can't find it. Or is it something special that only ET can source?

ET can get a better price than I can, but it's this really, (well, I hesitate to use the word "odd", but maybe it fits?) tweeter from Peerless... the DA25TZX00-08. It's rated 100W, which sounds a bit preposterous for a dome tweeter, except that it has this pretty unusual heatsink on it, with the input connectors on the back of that. And while you can take the front plate off (carefully) the motor VC is clearly connected back through the assembly to the banana sockets on the back.

As you can probably see, its a pretty monster ferrite magnet on it, too. The dome is the so called corundum dome; it's rather flat and shallow, and I don't know if that contributes to the wide off axis behavior. The grille is held on magnetically. These are bigger than maybe they look- about 4-3/4" in diameter.




There is a 32mm version which will undoubtedly play a bit louder, but doesn't measure as nice.

With the right crossover approach, it's my pick over a number of other tweeters I've gotten in to evaluate in the last several months which are generally 5-8 times more expensive.

Go figure...


And yeah, ET has been playing with this part in waveguides- the shallow construction and flat plate makes it pretty ideal for rear mounting... this supposedly has something to do with the "Tiny Technological Terrors" bit because he's found some off the shelf inexpensive WG that works pretty well together with this tweeter... not as well as a full blown optimized custom one, but still significantly better than unaided- about 10 dB improvement in loading in the lower frequency area.

[Scottg]

Here we have the crossover, built to the target form factor to see how comfortable it might be- lots of room on the board, actually. It's a mix of what I would call "upper mid Fi components" along with some better than average tweeter caps (Jantzen Lumen capacitors- pretty transparent sounding but without any glare or etch to speak of).

-speaking of upper mid-fi while "pumping" for value, note Tony's comment on the far less expensive Clarity Cap CSA (..particularly as you increase the microfarads):

"..I also found the CSA to mix extremely well with the Jantzen Audio Alumen Z-Cap. A mix of a minimum of 20% Alumen Z-Cap with the rest Clarity Cap CSA enhanced realism of space and lushness of tone. They blend together seamlessly."

[Steve Manning]

-speaking of upper mid-fi while "pumping" for value, note Tony's comment on the far less expensive Clarity Cap CSA (..particularly as you increase the microfarads):

"..I also found the CSA to mix extremely well with the Jantzen Audio Alumen Z-Cap. A mix of a minimum of 20% Alumen Z-Cap with the rest Clarity Cap CSA enhanced realism of space and lushness of tone. They blend together seamlessly."

Thanks for the info Scott.