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

[JonMarsh]

A different kind of driver... not your average 8" woofer.

The AS-190's arrived today as expected- boy, that was a heavy box! The magnets on these things look more like something you'd see on a 12" or even 15" sub driver.


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The main spider is where you would expect it- it's a flat spider, looks like it should be fairly high linearity.

Behind the main diaphragm, which is driving by the large titanium voice coil, is a sort of inverted surround, attached at the edges, and seems to offer pretty good throw and centering also. you can just see it a bit looking at the upper right...


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The pole piece vent is huge, following in the tradition of the other cell drivers, which attempt to lower the backside obscuring due to the magnet structure. OTOH, I'd say one would want to rebate this driver pretty much flush with the edge of the baffle, and take some care in relieving the inside mount on a thick baffle. I'm thinking the ideal thing might be two layers of Panzer Holz, then very little relief would be needed and it should be quite stout.

Talking about Panzer Holz is quite fun, as I'm about 3/4 of the way through "Wolfenstein: New World Order", which is a real hoot, and has a lot more heart and creativity than you usually see from that franchise- but then it was done by Machine Games, not ID.

[Face]

Talking about Panzer Holz is quite fun, as I'm about 3/4 of the way through "Wolfenstein: New World Order", which is a real hoot, and has a lot more heart and creativity than you usually see from that franchise- but then it was done by Machine Games, not ID.

That's a blast from the past, I haven't played Wolfenstein since Wolfenstein 3D.

Beautiful and interesting driver btw...

[JonMarsh]

Total Screw up, Serendipity, Rationalization or Pain?

What a day....

It's almost 9 tonight... I've measured the impedance of the driver, and actually looked at the labels...





Hmm hmm, that's the AS190-9-251, NOT the AS190-4-252 I had sworn I was ordering, with pleasure when I used the pull down box to select 4 ohm instead of 9 ohm...

That's the screw up.

Ok, so I start thinking a bit... hmmm, the 9 ohm driver is 85dB for 2.83VRMS; two in parallel will be 6dB more sensitive than one- and have 3 dB more output capability. So, 91 dB instead of 89 dB for the 4 ohm driver, and maybe even a smidge easier to drive.... plus that 3 dB more output.

What's the old saying? If some is good, more is better, and too much is just enough?

Is that the serendipity?


So, I have enough drivers to test and debug one cabinet, making one mid bass test enclosure if I use two drivers. Might even be able to shoe horn them in side by side, as they are really 7.5" woofers, not 8" woofers. The end product would look a bit weird, but I think there may be a way to make it work OK. would look like dual headlights on a Toyota FJ cruiser, I suppose. Even mounted that way, the piston range across the cone diameters for omnidirectional output is about 400Hz, which works for the planned crossover.

Sounds like rationalization to me, and that I don't want to let these drivers out of my hands and send them back to Madisound. I checked Madisound's site, and they show either version being a special order item now, 4 week lead time.

But then that leaves me needing to cough up nearly another $2K. For another pair. Ouch. That's painful. Very painful. But then I have an Apple dividend payment that will be coming up in the middle of May. Should cover most of that.

Patience, young Padawan... there is a reason for everything... even if it is NOT unfolding as I have forseen!

[meb46]

In advance to a potential weekend of modelling the "big" version of these, see below for a theoretical Baffle layout. I have tried to align the acoustic center's exactly, but have ended up a little short of perfection... will have to correct electrically in crossovers. Just as a reference, acoustic center's deviate from perfect time alignment (theoretically) by 1.5mm, 0.5mm, 8mm top down. I haven't worried about the subwoofers as we can fairly easily alter these with the DS8.0 Amplifier...

[TEK]

Have you evaluated to make them a bit lower, perhaps 170 instead of 190, and instead go wider and/or deeper to get the wanted volume?
How would that affect the timing, and the look? Maybe it's just me, but it seems a bit odd to have a couple of speakers that is actually higher than myself...

[meb46]

TEK - I had a play around with heights etc... but ended up on these based on a couple of factors...

1. I want the volume of the main Subwoofer cabinets to up towards 300L, which drives all dimensions to maximum possible without getting ridiculous - this requires in excess of 650mm deep, more like 700mm, which means this is a big enclosure. Overall, the aesthetic ratios during modelling look about right in my eyes.
2. I am taking into account the build process and panel thicknesses of 25mm which create limitations to the height of the mid cabinet and upper. Not to mention the 25L required for the upper bass cabinet coupled with somewhere to put the passive crossover into.
3. Lastly... I like the look of the current models and I think building on the aesthetics has merit... and I don't mind a speaker the same height as me

[JonMarsh]

Gee guys, just think how poor Neil Patel must feel- remember that picture at the start of the Unicorn dreams thread, they're a LOT taller than him!

That has me thinking, too, as it's looking like my updated mid bass design will have to add about 16" to the height if I do the more acoustically optimum things and have the two mid bass on each side stacked vertically. Those aren't short at all, already; but in a room with tall ceilings, I think they will work out OK.

And of course, I'm going to have to go back on my promise about no more crossover modeling, as now I need to model a mid bass setup with two AS190-9-252 on each side.... This is just going to push the 4pi space sensitivity up to 85 dB, best case, given 6 dB baffle step loss. Of course, sometimes it isn't a full 6 dB, we'll just have to see. But that will make them 6 dB overall more sensitive than the current version, which is limited by the 85 dB/2.83VRMS of the NS12-513-4A. (Which becomes 79-80 dB for 4pi space.)

[Steve Manning]

In advance to a potential weekend of modelling the "big" version of these, see below for a theoretical Baffle layout. I have tried to align the acoustic center's exactly, but have ended up a little short of perfection... will have to correct electrically in crossovers. Just as a reference, acoustic center's deviate from perfect time alignment (theoretically) by 1.5mm, 0.5mm, 8mm top down. I haven't worried about the subwoofers as we can fairly easily alter these with the DS8.0 Amplifier...

[ATTACH=CONFIG]25569[/ATTACH]

Mike ...... do you have a bigger version of this that you could send me, it's hard to see the dimensions in this picture.

[meb46]

Steve - See attached, this should be a little better...

[meb46]

Details missing as follows:

Width - 500mm
Spacers for Floor and between cabinets - 12mm (These will be Aluminum Plate). I am contemplating making the bottom plate 20mm Aluminum Plate to give myself more meat to thread in the feet.
Baffle - 100mm (Thinking either 4 layers of Horizontal Natural LBL Bamboo, or a custom lay-up of Horizontal and Vertical Bamboo runs)
Thickness and top Cabinet Slope - TBD based on volume calculations

The very top chamfer is incorrect, but will get ironed out in Solid-works

[Steve Manning]

That works ....... that's becoming a big beast.

[TEK]

Meb46:
This is actually happening? You are going to build these?
Are you going to do the building yourself? What finish are you thinking about?
(This is just so cool :-)

[JonMarsh]

Meb46:
This is actually happening? You are going to build these?
Are you going to do the building yourself? What finish are you thinking about?
(This is just so cool :-)

Oh yes, this is actually happening... remember, Mike is the only other builder of the Isiris, which were done using a vendor in Singapore for CNC work. But now he has his own CNC platform...

Remember, Mike had his own build thread....

https://www.htguide.com/forum/showthread.php?39507-Official-Build-Thread-MIC&highlight=meb46

And a very complicated MDF braced build:




He had some challenges with the finishing, but all's well that ends well...

[TEK]

Yes, I remember the MIC build. Great project.
I did not remember the matrix construction. Very nice!
Looking forward to following this build!

[CraigJ]

Jon,

Hope you are feeling better each day and trust that you are not physically overdoing it.

I think you forgot a slightly earlier and also complex build by Mike;

https://www.htguide.com/forum/showthread.php?36920-HiVi-Drivers&p=508059&viewfull=1#post508059

Mike, are you still in Chicago?

Craig

[JonMarsh]

No, not forgotten, but didn't team up with him until the pictured build, which started in 2012.

Mike took his toys and his wife and went back to Asia, based out of Singapore again, where he is traveling his butt off for his new company...

I've been to Singapore a few times on business, as we have a major headquarters there, but not in a few years. I still have to say I like the Orchard Road area, but then that's the real Gwai Loh part of town. :W If you're ever going there, I recommend the Royal Plaza, for a good mixture of value and service.

oddly, we were both in Germany about the same time last month, and he visited Accuton while I was hanging out at Campeon and visiting my Munich based friend and wife.

And, well, I've not been taking it quite as easy as probably I should, but I've been feeling better and getting things done this week... another procedure tomorrow! Joy, joy, joy!

[Horio]

Great job on the modeling so far Mike! Talk about some beastly speakers. All of a sudden, my planned Wavecor Ardent build seems so small.

I love big speakers, but just out of curiosity have you considered doing a 3-way tower with a second subwoofer module for each channel? I'm sure there are some tradeoffs going that route.

[sdl2112]

Very cool stuff going on here.:T ....now for a few random comments/questions.

Mike, any confirmation if/when you will get your hands on a C168?...and yes those are beastly yet refined looking. :B

I noticed on Madisound's website with Chrome the pull down options for the AS190 did not work so I didn't think the 4 ohm was available. I just tried with Firefox and it works...must be a settings thing.

Jon, what does the cone curvature look like from underneath (motor side)? I have always thought a "flying saucer" profile would perform well. Very strong profile if you could keep the weight in check.

I like the satellite/sub approach going on here as that is what I have in mind for my SSA-WG. I'll start off full range then add subs later if needed (likely in the form of end tables or similar). I have the option of sealed or ported with adjustable Qe via bucking magnets. This allows me to go with a sealed low Qts alignment with the subs.

[JonMarsh]

The cone seems to be a thin honeycomb in aluminum- so what you see from the underside is a what you'd expect for a constant thickness cone. Their supplied data is VERY flat form 100Hz to 1 kHz, which is pretty ideal for what I'm looking for... so, while this U-Turn of sorts may delay things a bit, I don't think it will hurt the performance of the end result. And later folks should be able to get the 4 ohm version with some ease... (famous last words...)

Think about it... this is almost going back to their roots for the inverted dome tweeters, which were not driven at the periphery of the dome, but with a smaller coil nearer the center- this better optimizes the use of the stiffness and moves the breakup mode higher in frequency.

Yes, though Mike and I both have specific ideas of how we want to implement the LF portion, in principle, there's no reason it can't be done with a number of different setups. Who knows, I might/could put the mid bass/midrange-tweeter module on stands and put the big cabinets off to the side walls- but I doubt I'll do it if I can get the cosmetics adequately working with my kluge approach!

And hey, Mike's design is not really all that humongous- 190cm tall, that's 74", or 6'2"- my height! If I do the kluge job on my Isiris, they will be taller, 63" existing, plus 16" if I stack the AS190's vertically (which I'm strongly inclined to do for a variety of reasons related to directivity and enclosure design). 79". Yowza... better keep them in three pieces.

[meb46]

TEK - Yes, confirmed as per Jon's comments, this is happening. It will most likely be a relatively slow build as my wife and I have our first child due in June. I'm sure that will slow things down, hence I'm trying to be as active as possible now procuring everything I need in advance. I have pretty good access to CNC facilities, machining team, furniture making personnel, so I may end up "delegating" some of the work. What I want to have completed by early June is the Solid-Works models, completed a dummy sample of the Middle and Upper Cabinet Baffles to send to Jon to aid in the testing of the AS250 and CS168. But who knows, I might get further... For finishing, these will be the same as my current speakers... Matt White. The clean look, coupled with the Accuton Driver colors gives a really contemporary look - which I really like.

Craig - Hello again, as Jon mentioned, we are now back in Singapore, unexpected, but enjoying the tropics again... unlike our Miniature Schnauzer who is suffering terribly from allergies and the heat/humidity combination. Its an easy place to live, but just terribly hot and humid. My first "big" build was flawed from day one, little thought went into it other than making really awkwardly big speakers. The MIC Project, with Jon's help, was a great success and I have been really happy with them. As always, hobbies are never ending, and the desire to make something better is always snapping at our heals. This also means I get to fix that what I didn't like in the MIC project... external crossovers, build structure/process, the fact I know every imperfection in the finishing (no one else can see them, but I know they are there)... etc.

Horio - Thought about independent satellite style subs... but I have always been of the opinion that a speaker the size of the MIC/Isiris etc. should be a one/stop/shop and perform independently of subs... But granted, these now have the main cabinet as subwoofers (Dual 15"). I guess the other fact is that I just like big, speakers that have some "wow" impact. My wife has been happy with the MIC project as they are contemporary looking, and she refers to them as more of a center piece/art... which really helps my argument for the next generation... same look, same finish, just grown a little

sdl2112 - Yes, the C168's are hard to get given they are new and willingness to build these limited due to lack of commercial designs using them. I would assume supplying to the DIY community would be a second priority after commercial demand. I have been exploring a few commercial things in China over the past few years, and I want to get Accuton into the mix on this.

Love the term Jon - "Humongous"... I'm thinking that until I need a forklift to move these, then everything is acceptable Each time I move these things, I'll just rally the lads and offer free beer to provide relocation services!

[dar47]

Brovo!, you sir are manly man and a lucky one to boot that has a partner that has a real eye for fashion.:W

[cochinada]

I guess the other fact is that I just like big, speakers that have some "wow" impact.
...
... I'm thinking that until I need a forklift to move these, then everything is acceptable Each time I move these things, I'll just rally the lads and offer free beer to provide relocation services!

Very interesting project! I'm with you as I also like big speakers but I'm wondering how much these beasts will weight in the end. I believe you mentioned that just the baffle alone will be 100mm thick? :E

I don't know what is the thickness of the other panels but judging from how tall it is, I would estimate a final weight of no less than 500lbs or even more. Now that's the proper definition of humongous on my book. :agree:

About this baffle, being so thick, how are you going to cut the holes for the drivers? I believe it will consist of some sort of a sandwich of different materials right? If so, will you cut a hole on each one before gluing them together or what? And then, how can you be sure they will be perfectly aligned and not slide during the process? Or do you have a special humongous tool for drilling a hole through 100mm thick? Or...? :scratchhead:

[meb46]

Joaquim... I'm thinking a finished weight of around 200Kg, so similar to your prediction... Bear in mind Amplifier for the subs, crossovers and the fact I am using separation and base plates made of aluminum. For the machining, this is typically done from both sides using a CNC Router. The way this is done is by using tooling pins and two router paths. You locate the raw material on tooling pins and route from one side and then flip... there's software that can help you on tooling pin location etc. Its actually a pretty straight forward process. Typically, a decent CNC Router should have around 120mm z axis, so this covers the requirements. It is very time consuming depending on your design... these will have a flare in behinds each of the drivers which adds to the machining time. I don't expect anything less than 2-3 hours machining on the Bass Cabinet Baffle alone.

[cochinada]

I see. I had this (wrong) notion that a typical CNC could not drill more than 30mm or so but your explanation made everything clear now. Thanks!

I'm also rereading your fantastic earlier MIC project. By the way, and this goes to all of you guys: what the hell do you do with so many speakers that you build? I believe it's physically impossible to keep them all at home unless you people all live in big mansions. The alternative of selling a DIY speaker shouldn't be easy. I know because I couldn't sell my previous one that ended up in my small basement where it is left abandoned. At least here in Portugal nobody cares if you don't have a brand name behind it which is a shame. But your 'Isis' version deserves a good home and not end up in a storage like mine did.

One more thing, I'm not sure what drivers are you going to use in this new project as I cannot see very well what you wrote on your drawing and I also think there might be some lateral drivers perhaps?



EDIT: now I saw that you are a 'kiwi' . Not sure if you like rugby because I once met another kiwi that strangely enough didn't, although curiously he went to school with Ben Smith, but I'm a huuuuuuuuuuuuuuuuuuge fan of the mighty All blacks. :clap:

[JonMarsh]

I shouldn't answer for Mike, but on the driver score- this is easy- as I'll be doing the testing and characterization for him:

Woofers: Acoustic Elegance TD15's on order

Mid woofer: Accuton AS250

Midrange: Accuton C168

Tweeter: Scanspeak D3004/7140

[meb46]

Slight correction... Tweeter Scan-speak R2908/714000

Its Friday Jon, and you had an Operation this week...

[cochinada]

Hummm can't find it. Isn't it D2908/714000 instead?

[meb46]

Argh... Yes, you are right! Serves me right for making fun of Jon

[TEK]

Argh... Yes, you are right! Serves me right for making fun of Jon

And I who tought it was a concerned comment 8O

[meb46]

And so the late nights on Solid-works begins...

A few "in-progress" changes, but things are taking shape slowly. The top and mid cabinet chamfers didn't quite eventuate as planned... but still look good. This time on the rear of the baffles I am opting to machine clean perpendicular surfaces edges and not chamfer/tapered - The flared ones used in MIC #1 simply added hours to the machining time... this time its simpler, and still gives plenty of breathing room behind each of the drivers.

[JonMarsh]

Looking good, Mike. I still was so busy this weekend I didn't have time for Fusion 360- will start on that tonight.

Crossing my fingers that you get a shipping update soon.

[meb46]

Jon - Ditto...

Already spent a few hours last night rethinking some of the geometry above... this coupled with some very slow Solid-Works cogs turning last night on better ways to construct the Baffles and calculate the facet angles. More tonight...

[cochinada]

Jon - Ditto...

Already spent a few hours last night rethinking some of the geometry above... this coupled with some very slow Solid-Works cogs turning last night on better ways to construct the Baffles and calculate the facet angles. More tonight...

That's the most fun part to me. :T

[meb46]

Slight amendment in the profiles... Still have the rear surfaces to modify and also the Screw/Boss fitting on the driver mounting surfaces.

[cochinada]

Looking good. :T

[JonMarsh]

So, considering voicing issues and the use of 2 AS190-9-251, I went back to VituixCAD and prepared a concept engineering update. Using the dual AS190, the net sensitivity is increased by about 2dB and the impedance can be a skosh higher in the mid bass section (that isn't seen here, as VituixCAD just connects the active powered NS12-513-4A in parallel with the passive part of the system, regarding impedance). This is just a proof of life, no expectation to be a final design, but it I don't see any big obstacles once I have new measured data.




Next step is building the temporary mid bass acoustical test enclosures for evaluation. Parts are here, but have a pretty booked weekend already with Class D stuff and the Minvervas!

[meb46]

Front Baffles nearing a first draft completion... couple of points to note:

1. All Cabinets will have a single vertical brace connecting the rear panel to the front Baffle/Top/Bottom
2. The Subwoofer Cabinet will have two horizontal braces connecting the sides, front Baffle and Vertical Brace, plus two smaller horizontal braces just behind each of the woofers that don't touch the Front Baffle... does all depend on volume depletion before finalizing
3. The C168 is primarily vented through the back of the speaker where on a traditional driver design would be the magnet. This means I can limit the chamfer/flare required in the back of the Baffle
4. I will most likely add a slight chamfer/flare to each of the driver mounts on the rear of the baffle, but this will be done separately to the models as I need to gauge the "meat" left in the Baffles after machining

[sdl2112]

Mike,

Curious, will you have a brace between the two subs where the baffle is the thinnest?

-Scott

[meb46]

Scott, there is a horizontal brace that attaches to the two fingers at the sides in that area... Not directly to the thin part. One point to note, although it looks thin, remember the basic reference geometries, those are 15" Woofers, and what looks thin is still actually quite sizeable cross section. I will have another look at that area, but I think we are good. It's also going to made out of Horizontal Natural LBL Bamboo... Which should cover strength concerns...

Starting on the bracing at the moment... Should have some first hits in a week or so... One big factor is the size requirement of the amplifier going into the sub cabinet. At the moment without bracing it's about 300L... And I don't want to loose much due to the plate amplifier...

[meb46]

Quick update... Driver arrivals now a steady stream at my front door! Photos coming shortly!

[JonMarsh]

Yup- Mike has scored Unobtanium, in terms of us mere mortals... but I'll leave the details to him!

[meb46]

Photos of the "Unobtainium" will have to wait today... instead some updates on the Enclosure models. Subwoofer Cabinet is nearing completion and currently has no allowance for an Active Plate Amp. This may end up being altered, or I may just keep the amplifiers separate to ensure I don't consume box volume - still to be decided.

Subwoofer Cabinet uses two larger braces to tie the Baffles into the main vertical brace. Section between woofers has been checked and confirmed plenty of "meat". I do not think this will be an area of weakness.

Bass Cabinet has a single vertical brace and doesn't tie into the front Baffle. This shouldn't be a problem as the sides are all 25mm and the front baffle 300mm high, so again, plenty of "meat" to epoxy the sides to the baffle and ensure minimal vibration.

Top Cabinet dimensions and angles in progress over the weekend!

[cochinada]

Don't mean to criticize but rather give some constructive opinion: don't you think the vertical brace is a little 'hollow'? It's just my intuition but perhaps the holes should be smaller to give it more consistency.

[JonMarsh]

Interesting question- certainly would be my thought if they were made of MDF. With LBL, things are a bit different. And perhaps there is some desire for weight control?

My inclination for the vertical front to back would be KISS, and that could be a near solid sheet of BB ply.

You have to work with LBL a bit to really appreciate how strong the good stuff is- it's like working with Maple. A piece of 3/4" MDF that I can easily snap across my knee in LBL would simply do so much damage to my knee that I'd have to see an Ortho guy afterwards... And the LBL would only be mildly annoyed, certainly wouldn't be broken...

[Steve Manning]

Photos of the "Unobtainium" will have to wait today... instead some updates on the Enclosure models. Subwoofer Cabinet is nearing completion and currently has no allowance for an Active Plate Amp. This may end up being altered, or I may just keep the amplifiers separate to ensure I don't consume box volume - still to be decided.

Subwoofer Cabinet uses two larger braces to tie the Baffles into the main vertical brace. Section between woofers has been checked and confirmed plenty of "meat". I do not think this will be an area of weakness.

Bass Cabinet has a single vertical brace and doesn't tie into the front Baffle. This shouldn't be a problem as the sides are all 25mm and the front baffle 300mm high, so again, plenty of "meat" to epoxy the sides to the baffle and ensure minimal vibration.

Top Cabinet dimensions and angles in progress over the weekend!

[ATTACH=CONFIG]25723[/ATTACH][ATTACH=CONFIG]25724[/ATTACH][ATTACH=CONFIG]25725[/ATTACH]

Drawings are looking good Mike ...... what software are you using?