Official Build Thread - MIC

[meb46]

As per previous "New Project Critique" thread, I am starting a new thread to document my build progress over the next few months. Please dont expect things to happen quickly as this is a lengthy, somewhat complex build that I expect with take the best part of 6+ months before it resembles an actual speaker.

For those that aren't up to date on this, it is an Avalon Isis style cabinet as shown below, utilizing dual Aurasound NS12-513-4A + Accuton C173-6-90 + Scan Speak D3004/664000... Partially complete Solidworks Model Below...



The Model is still missing the completed Mid/Top Cabinet, but this should be completed in the coming week... will update once completed.

Progress as of today on the build schedule is the ordering of the front Baffle Material. I am using a five layer sandwich Front Baffle of MDF + Hardwood Ply + MDF + Teak/Birch Ply + MDF. Total Thickness is just over 100mm. The 5 layers are being glued together with Phenol Formaldehyde Glue and then pressed until cured. This should give me a relatively strong and durable Baffle to then have machined. The press s a slightly modified full panel veneer press at at a local factory. The panels shoud be completed but the start of Februay, so watch this space for the un-machined sandwich Baffles...

All internal panel machining files should be finished in the next week and will then go to my machinist. Hopefully these are processed quickly and easily...

More updates to follow...

[Hdale85]

That's not an invisible 4x8 sheet next to it is it?

[meb46]

Not quite... its just the invisible side wall when I extracted the image from Solidworks... Bass Cabinet is 1200mm high by 380mm wide. Not what you call a "small speaker"

[Hdale85]

4ft is much different then 8ft though! haha! I thought we were looking at 10ft tall monsters! But the proportions weren't adding up anyways

[bbcmp1979]

For some reason, that looks real nice for an open baffle... :-)

[meb46]

Random question... If I decided I wanted to switch to a Accuton Ceramic Tweeter in place of the Scanspeak D3004, what Accuton tweeters would you recommend to go with the C173-6-90? I would have thought it make more sense to opt for a Ceramic Tweeter to accompany the Ceramic Mid, or is this able to be overcome with Crossover wizardry? -m not proposing a change at this stage, but merely running the thought through my head... Thoughts?

[Generic George]

Random question... If I decided I wanted to switch to a Accuton Ceramic Tweeter in place of the Scanspeak D3004, what Accuton tweeters would you recommend to go with the C173-6-90? I would have thought it make more sense to opt for a Ceramic Tweeter to accompany the Ceramic Mid, or is this able to be overcome with Crossover wizardry? -m not proposing a change at this stage, but merely running the thought through my head... Thoughts?

I don't know enough about the individual units to offer a useful opinion on which would be better, but I can tell you that the type of tweeter and materials of the tweeter are much less important to the crossover design/performance than the actual characteristics of the tweeter. Nothing about them being of similar type/manufacturer/material will automatically make them better suited to working together.

IMHO, if you are looking at something different for a tweeter, I'd probably look at one of the ribbons like the various RAAL units. Those get used in a LOT of really good designs.

[JonMarsh]

Not quite... its just the invisible side wall when I extracted the image from Solidworks... Bass Cabinet is 1200mm high by 380mm wide. Not what you call a "small speaker"

If you have a solid works model, would you be willing to share? I don't use solid works, but believe I can import it.

Nice to see someone doing something like this, and that you have such "manufacturing" resources available!

I'll be following this with interest...

[JonMarsh]

Random question... If I decided I wanted to switch to a Accuton Ceramic Tweeter in place of the Scanspeak D3004, what Accuton tweeters would you recommend to go with the C173-6-90? I would have thought it make more sense to opt for a Ceramic Tweeter to accompany the Ceramic Mid, or is this able to be overcome with Crossover wizardry? -m not proposing a change at this stage, but merely running the thought through my head... Thoughts?

I'd have to take a look at your front panel- size limitations and all-

Right now, the diamond tweeter used in the Isis is the larger 1.2" version- if you wanted the similar ceramic tweeter, with Neodymium underhung motor, that would be the C30-6-024.



I would look at the front panel space available and consider the Transducer Labs N26c. I've got two pair, will be testing in a direct radiator configuration and waveguide. But, to get the relatively low price, they don't use Neodymium, and the magnet assembly is fairly large in order to get 90 dB sensitivity with an underhung motor permitting fairly good output at low frequencies.

http://www.transducerlab.com/media/eab5a0aa8566f0cffff804dffffa126.pdf

Meniscus seems to be having trouble keeping them in stock, mainly because a lot of folks are interested in them due to the cost/performance ratio ($137 each at Meniscus; sold only in matched pairs).

[meb46]

Jon - Thanks for the information, this is appreciated. I'm going to have a think about a slight deviation from the Scan Speak Tweeter... more information later.

Definitely happy to share the designs with you once I have finished the assembly. I have another week or so to finish the top Cabinet Design then I will let you know.

George - Thanks for the notes, I have seen a lot of designs/discussion using the RAAL Ribbons and they have some real avid follows

[Hdale85]

That Meniscus looks real nice for the money!

[meb46]

Finally a finished cabinet model in Solidworks (The joys of a 4-day weekend)... A few minor changes to volumes and bracing, but essentially the same as per the earlier Google Sketch-up Verison.

Aside from some minor interferrence issues, the assembly fits together as expected. I have created a number of slightly oversized panels to then enable me to cut-down and fit exactly... just incase the CNC proves to have more tolerance issues than expected. The model doesn't include all of the radii on the internal braces as these are not part of the CNC requirements. I have include the taper/chamfer on the inside of the Baffles now which has given a significant volume increase... which will need to be accomodated in the overall cabinet damping/fill etc.

I have had a slight change in the tweeter I am going to use... have decided to take a slightly risky... NEW tweeter... more details to follow soon once I have confirmed I can get them... This will mean some advanced testing before I confirm the exact part...









Next step is to have Panels quoted and cut. The Front Baffle Sandwich has started and is due around the start of February. With any luck I wont have a coronary at the price of all the CNC machining...

[JonMarsh]

Interesting! Risky is fun, even though it's, well, risky!

[JonMarsh]

Finally a finished cabinet model in Solidworks (The joys of a 4-day weekend)... A few minor changes to volumes and bracing, but essentially the same as per the earlier Google Sketch-up Verison.

Aside from some minor interferrence issues, the assembly fits together as expected. I have created a number of slightly oversized panels to then enable me to cut-down and fit exactly... just incase the CNC proves to have more tolerance issues than expected. The model doesn't include all of the radii on the internal braces as these are not part of the CNC requirements. I have include the taper/chamfer on the inside of the Baffles now which has given a significant volume increase... which will need to be accomodated in the overall cabinet damping/fill etc.

I have had a slight change in the tweeter I am going to use... have decided to take a slightly risky... NEW tweeter... more details to follow soon once I have confirmed I can get them... This will mean some advanced testing before I confirm the exact part...









Next step is to have Panels quoted and cut. The Front Baffle Sandwich has started and is due around the start of February. With any luck I wont have a coronary at the price of all the CNC machining...

Thanks for the STEPS export- no problems bringing them into Shark FX, including the full assembly drawing.

I think the person that might have the coronary would be me, making these parts manually! I'm also going to have to check the local LBL ply sources- I do have several 8' 12" wide LBL boards.

I can already see ways that I'll modify some parts like braces for "manufacturability" with my available tools as well as possible strength impacts. They'll probably wind up looking more like some of the Ardent pieces.

I hope to be able to find time this weekend for a complete review, though it may have to wait until next weekend when I'm in Orlando for the APEC conference. I prefer working on a bigger screen than that built into the 17" MBP.

[Ray_D]

Side panel bracing

A very interesting project.

Your side panel bracing effectiveness is being compromised by the slots cut in the braces. In particular, the slot in the vertical member at the bottom completely negates its effectiveness. Most of the cutouts are larger than necessary for air movement and I suspect smaller ones would not represent a significant volume loss.

Good Luck!

Regards

Ray

[meb46]

Ray - thanks for the notes... during the design phase of this I had looked at other CNC machined panels that I have had made and I found that the 25mm thick MDF actually remained relatively rigid when machined like that. I was alternatively thinking of just putting ribs to brace the side panels in the lower chamber, but then switched to what I have now. The way I justified that style was the fact that it is to tie the bottom and side panels together and offer a verticle rib. Alternatively I could add a joiner in the part you refer to so it hase two separate slots and not the single full length one. This may be a good compromise.

[meb46]

Further note - It may make more sense for me to also add one of the packers used to brace the two mid scections to the sides in the lower chamber rear. This would add additional support to the side panels in the lower chamber. Then again... these are very heavily braced as is... and I may now just be "over-doing" the bracing... but is there such a thing

[meb46]

Slight Amendment with the lower Chamber Bracing in response to "Ray's" notes... I'm still weary of the volume so the Braces have a slot in them still. Due to the size, the slot shouldn't reduce the overall strength and purpose of the braces. Upside... I have managed to standardize this part and hence reduce the number of different parts by one...

[Beau]

Mine dont have half the bracing that yours do, should be EXTREMELY inert!!
Mine do have curved sides so I guess that would add to it. They are pretty much as pictured below but with a shelf brace just above the PR openings on the side.



Finished look somewhat like yours, looking forward to this.

[Paul W]

I have managed to standardize this part and hence reduce the number of different parts by one...

I'd make 8 more of those little jewels and add them at the rear of both woofer chambers

[meb46]

A slight deviation/change in the side bracing to enable greater support of the side panels. This version uses a Matrix interlock of full length vertical braces into the main horizontal braces. This should absolve concerns on the Side panel bracing. Files sent to machinist today... so hopefully no surprises...

[meb46]

Beau - Your Cabinets look very good with the curved panels. Can you give me some more information on yours? Drivers etc? Most importantly... how do they sound? Happy with your efferts vs pay-off?

[Hdale85]

Yes Beau's speakers are gorgeous, I was hoping he'd do a nice writeup and crossover design and such in another thread but so far nothing. Although I think maybe they are active? Can't remember. I'd be extremely happy with those though.

[meb46]

Yes - agreed. They look great!!! Also, I wonder what Beau powers them with... are we talking large solid state?

[Beau]

Hey guys, thanks for the compliments.

Dont really have many pics. I did have step by step pics of construction but deleted them in disgust one day when I was convinced id never finish them....
The crossover is as designed by Jon for the Modula extreme, slightly modified.
Reason being the woofers ( acoustic elegance av10h) have a lower sensitivity than the original scans.
Crossover is all passive, middle of the road components Dayton/jantzen etc..
Amp atm is a stereo Ucd400. Just finished building an integrated remote volume/mini dsp to actively triamp the whole shebang.
Anyone want to buy some boat anchor crossovers?

[meb46]

Beau - what are your listening impressions? Worth the effort?

[JonMarsh]

Looking good, Mike

A slight deviation/change in the side bracing to enable greater support of the side panels. This version uses a Matrix interlock of full length vertical braces into the main horizontal braces. This should absolve concerns on the Side panel bracing. Files sent to machinist today... so hopefully no surprises...

A lot of people will be following this one.

Hope to get my broadband back up at home this evening, with the PSP power supply I ordered.

***************

PSP supply worked- DSL modem operational again.



Found all four of the NS12's, too, so it's looking interesting. Hit the piggy bank for construction materials and crossover parts. I had second gen midrange crossovers designed and bought but never installed for the Modula Xtreme's.

Unfortunately, things are really heating up at work at the same time- and earlier we thought this would be a slower year due to the economy!

[meb46]

I just unpacked my NS12's... they really are a VERY nice driver... The cones are very ridgid compared to some of the other drivers I have used, and the use of the Neodymium Radial Magnets makes for a comparatively "light" weight. Build Quality also looks very good, and for once... the physical dimensions actually match the datasheet

[JonMarsh]

Build Quality also looks very good, and for once... the physical dimensions actually match the datasheet

Isn't it really NICE when some one does that once in a while? :B

[meb46]

Jon - Haha, yes it is nice... it's one thing that constantly gets to me is the fact that basic dimensions vary so much in what "should" be a preciosion process. Cast Frames and Powder Coating are controllable/predictable processes, yet so many suppliers have extreme tolerances. When you have cut-outs CNC Machined to around +/- 0.5mm, variances in Speaker frames start to be a issue.

Just had a call from my Baffle Material Supplier, the bare/un-machined baffle Ply/MDF Blocks are ready for delivery... Should have these by tomorrow and will then post some "before" shots of the material before machining.... things are moving ahead

[JonMarsh]

Jon - Haha, yes it is nice... it's one thing that constantly gets to me is the fact that basic dimensions vary so much in what "should" be a preciosion process. Cast Frames and Powder Coating are controllable/predictable processes, yet so many suppliers have extreme tolerances. When you have cut-outs CNC Machined to around +/- 0.5mm, variances in Speaker frames start to be a issue.

Just had a call from my Baffle Material Supplier, the bare/un-machined baffle Ply/MDF Blocks are ready for delivery... Should have these by tomorrow and will then post some "before" shots of the material before machining.... things are moving ahead

Cool!

I'm looking at a more basic kind of outsourcing/insourcing- discussed with my girlfriend hiring her son to help with the big sheets of bamboo ply and doing the cutting. And I've rented a small space dedicated to storage and assembly for this project. That should motivate me not to lollygag too much!

You're going to be way ahead of me in no time- and this Saturday I leave for the IEEE APEC conference in Orlando. I'm not going to order the bamboo ply until I get back. I've still got to finish review of the updated models, and preparation of an alternate based on bamboo ply. And a cutting plan with some material buffer- left overs for another small project would be welcome, anyway.

[meb46]

We have now reached the point of no return...

Baffle material was delivered today. As mentioned before, these are a MDF/Ply Sandwich up to 100mm thick. They have been pressed together using Phenyl Formaldehyde Glue as full panels and then cut to the respective sizes ready for 3D CNC Machining. The bare un-machined Bass Cabinet Baffle are already around the 30kg mark, so not the lightest of things and the Mid Cabinet Baffle around 12kgs. Some of the weight will be shed once machined, but at least I am starting with a solid block





There is some very small voids in the Ply on the cut edges, but these are very small and shouldn't poase any problem.

Spent some time with the Machinist today so now some degree of the success of the project rests in his hands.

Updates to follow in a week or so after I have some parts back from the machinist... until then, I wait in anticipation...

[Hdale85]

Formaldehyde glue hmm......wear a respirator when machining them

[meb46]

My thoughts exactly... I am assured that it is no worse that standard MDF content... Hmmmmm.... Dubious about that either way...

[cjd]

My thoughts exactly... I am assured that it is no worse that standard MDF content... Hmmmmm.... Dubious about that either way...

most mdf really is that bad. its why i don't use it.

[sorue]

meb46: Great stuff! Are you a fellow SGer? Remember reading somewhere that you are. Incidentally i'm doing a isis style cabinet too, but with primitive tools. I was going to ask you where you sourced your ply from. It's difficult to get high quality void-free ply in SG. What's your nick in XP?

[meb46]

Sorue - Not a fellow SG'er, i'm a Kiwi (New Zealander) living in Singapore On the Ply/MDF just PM me if you want the details etc. I have a relatively good supplier, but still not completely void-free... Great to hear some one else attempting an Isis Cabinet... make sure you post some pic's so we can see your progress. What drivers are you using?

[meb46]

In preparation for the assembly process, I am going to create a "dolly" to move these around with. I have a couple of weeks before I get the machined parts back, so I need to keep enthused... hence I am going to create an easy way to move them around as they gain weight... instead of crippling myself

[JonMarsh]

In preparation for the assembly process, I am going to create a "dolly" to move these around with. I have a couple of weeks before I get the machined parts back, so I need to keep enthused... hence I am going to create an easy way to move them around as they gain weight... instead of crippling myself

Very necessary! I did the same thing for my Ardents, once I had the pieces far enough along to start assembling cabinets. You should be at that point a lot faster, given how much work you're farming out- very expedient!

Jon

[Bear]

In preparation for the assembly process, I am going to create a "dolly" to move these around with. I have a couple of weeks before I get the machined parts back, so I need to keep enthused... hence I am going to create an easy way to move them around as they gain weight... instead of crippling myself

Also think about other tools/jigs that will help move them around (e.g., Jon's "lazy susan"). Even a basic stand-mount monitor can be a handful to finish, so think ahead to the finishing process and how you will need to navigate around it. Then think about the measurement process and voicing the crossover. Some of the best tips here are from people getting creative about how to sling around heavy wood assemblies in an efficient fashion. :T

In other words, I wouldn't stop at just a dolly! For example: say you want to veneer the beast. Is your work table at the right height so that you can stand over a side and do the veneer application, sanding, staining, sanding, staining, etc. Probably not, so a short work stand might be in order. If you are going to paint, likewise do you have the set-up to apply the type of paint you want in a fashion that works (e.g., some people have suspended their cabinets for automotive-style paint techniques). Check out the "show us your finishes" thread (or something similar) for ideas.

[JonMarsh]

All good suggestions....

Also think about other tools/jigs that will help move them around (e.g., Jon's "lazy susan"). Even a basic stand-mount monitor can be a handful to finish, so think ahead to the finishing process and how you will need to navigate around it. Then think about the measurement process and voicing the crossover. Some of the best tips here are from people getting creative about how to sling around heavy wood assemblies in an efficient fashion. :T

In other words, I wouldn't stop at just a dolly! For example: say you want to veneer the beast. Is your work table at the right height so that you can stand over a side and do the veneer application, sanding, staining, sanding, staining, etc. Probably not, so a short work stand might be in order. If you are going to paint, likewise do you have the set-up to apply the type of paint you want in a fashion that works (e.g., some people have suspended their cabinets for automotive-style paint techniques). Check out the "show us your finishes" thread (or something similar) for ideas.

In fact, I'm ordering one of these, on sale, just because of things you're mentioning- while my old tables groan a bit under 100 lb, something like this would totally stress them out!

[meb46]

Managed to get the Dolly completed last night... Probably overkill on the thickness of it, but I guess no qualms on holding excess weight. I will probably make a second one so each speaker can reside on them when I need some space...

For work benches I am relatively well equipped with adjustable horse stands etc. My last project meant I have geared up with everything I need... The last project was one with curved sides and I ended up making cradles for them to assist in veneering. With this project having flat sides, I see the whole finishing process a great deal easier.

I do like the idea of Jon's rotating platform, so I might make something similar to this.

I do have one question as to "how to"... The 100mm precision port that I think I will use arrived from PE yesterday and I now understand how big the flare is where it sits into the base of the cabinet. To accommodate this I will need to increase the base of the cabinet a little to secure it properly. This will just be done with an additional sandwich piece of MDF in the cabinet... However... I need to route in a very deep and large curve for this to fit. All of my standard curved router bits only go up to about a half inch radius... Any creative way of being able to route some to about a 1" radius? Anyone know if you can get 1" or 1.5" radius router bits on a 1/2" chuck?

[Hdale85]

All good suggestions....




In fact, I'm ordering one of these, on sale, just because of things you're mentioning- while my old tables groan a bit under 100 lb, something like this would totally stress them out!

Why not build your own? There are some awesome plans out there using SYP (southern yellow pine) that are pretty inexpensive and much better then that table.

[JonMarsh]

Why not build your own? There are some awesome plans out there using SYP (southern yellow pine) that are pretty inexpensive and much better then that table.

Time.... time is money, and what I have far too little of is spare time. I could build room treatments, benches, all kinds of stuff, but I have so little spare time because of work. last year I didn't have a day off between July 5 and September 30 due to work load and crazy assignments.

[JonMarsh]

Managed to get the Dolly completed last night... Probably overkill on the thickness of it, but I guess no qualms on holding excess weight. I will probably make a second one so each speaker can reside on them when I need some space...

For work benches I am relatively well equipped with adjustable horse stands etc. My last project meant I have geared up with everything I need... The last project was one with curved sides and I ended up making cradles for them to assist in veneering. With this project having flat sides, I see the whole finishing process a great deal easier.

I do like the idea of Jon's rotating platform, so I might make something similar to this.

I do have one question as to "how to"... The 100mm precision port that I think I will use arrived from PE yesterday and I now understand how big the flare is where it sits into the base of the cabinet. To accommodate this I will need to increase the base of the cabinet a little to secure it properly. This will just be done with an additional sandwich piece of MDF in the cabinet... However... I need to route in a very deep and large curve for this to fit. All of my standard curved router bits only go up to about a half inch radius... Any creative way of being able to route some to about a 1" radius? Anyone know if you can get 1" or 1.5" radius router bits on a 1/2" chuck?

MLCS has large round over bits- 1-1/2" takes some care in using. I would suggest a straight 45 degree bevel bit, probably easier to find.

http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/katana_bits2.htm