Neatly split sub-forums

[Quza]

I just noticed I don't really browse this forum anymore. I click on Development tools & techniques, check for new VituixCAD comments and then leave.
As there are no other threads in the sub-forum there's nothing to interact with without clicking a few times. With the old sub-forum Mission Possible DIY there was always something to catch the eye.
Could those sub-forums be merged again?

[technodanvan]

I sort of agree, while I like how everything is split up I think that really only works if we get a lot of traffic.

[JonMarsh]

I'm getting the impression this comment is mostly about Mission Possible DIY... correct? I don't have any authority as a moderator outside that area and the "On the Bench" section.

You know my next question- why did you post it here, given that the general Mission Possible DIY forum still exists, as a catchall for stuff that doesn't fit to one of the sub forums? If you agree to it, I would prefer to move this topic to the main section of Mission Possible DIY- that's where I'm a moderator.

Don't misunderstand my intent here- I think you raise some good questions, and I have a lot of thoughts to share in answer, more than are going to fit in one post, so I'll outline the high level points, then fill in as I have time.

I'm guessing that the info posted about current design studies and projects in development being updated in progress over the last few months doesn't hold much interest for you then... I wonder if it would have any more interest if it was all in one stream? It's easy to tell if there's new stuff posted or not in each section. Of course, if your interest is very specific to the topics you mention, (a very understandable set of choices) then this new organization does allow you to zero in on that stuff, separate the wheat from the chaff, so to speak.


So, let me outline some issues and concepts- and you're encouraged to give feedback, of course.

• Search and discovery:
  • The (very) old rev of software being used by HT Guide when Sven took it over was not setup to handle Google search inquiries properly. Sven fixed this and a lot of other things with the new (very major!) update to the software.
  • There are a lot of long in depth topics on projects, and for specific builds, that even for those who have been following HT Guide closely for many years might have trouble locating to check info or follow up on an idea they didn't have time for back in the day- for those new to HT Guide, not having the right search terms, it would be near impossible to dig up stuff.
  • Categories for posting help with search and investigation for more casual users- some may be interested more in build stories, and not getting into the nitty gritty covered in design studies or project development.
• New Projects- the right half plane zero problem. Everything has taken longer to get off the ground on my side this year, and talking to Steve and a few others, the situation is similar. Corollary includes "Slow work takes time"
• Life is what happens while you're busy making other plans... a contributor to the "right half plane zero" issue for new projects.
• Supply chain issues impacting DIY speaker building - and our efforts to address this with upcoming projects
• The economic, geopolitical and personal issues impacting activities requiring spare income and time- re HT Guide projects
• Does the world really need another 6-1/2" two way? Maybe... especially to introduce new folks into DIY at higher bang for the buck performance levels.

Right Half Plane Zero problem...

Now, what do I mean by the right half plane zero problem? This term describes a transfer function condition that exists for certain classes of SMPS converters operating in continuous conduction mode (an energy storage inductor always carrying current, not declining to zero unless the output load is removed) which basically creates an interesting "problem" in that when you try to increase the output quickly by increasing duty cycle of the converter, it actually initially dips the output, then it recovers. In practice, what this means is that you have to limit the first derivative of change of the driving function- in practice, that means a very slow control loop and slow response to load changes. Do you want to know more? Google is your friend.

But it's a good analogy, for example, for the challenges Steve Manning has had setting up the new workshop in Maryland, and it also seems to apply well here in Idaho for getting my projects going. In my case, the delaying issues have been work to be done on the home both for the workshop aspects, and just for moving into and setting up a new home.


Life is what happens while you're busy making other plans...


And aside from that, there has been an unexpected amount of family drama in offspring, necessitating trips to CA and taking care of grand children for a week or attempting to intercede in other issues... unplanned stuff, you know. This is part of the "life happens" issues, of course. And I've personally become a lot more involved in what I'd call "health maintenance consulting" with family and friends.

The book at this link will give you an overview of the core in that topic which I've been doing over 20 years... not everyone I know is interested in this stuff, but some former colleagues have told me they think I've saved their lives...

https://www.amazon.com/gp/product/B0731L3MF8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

So this is just a contributing factor to the delays in what I'd really rather be doing in my retirement... instead, I haven't even had time to hook up my TV or CD players and basic two channel music system- evaluation of prototype builds has been done via the electronics in the two new acoustic test carts I've put together, because somehow the gear I was originally using up until April/May got "misplaced" during moves and storage work, and for the life of me, I haven't been able to find those microphones, preamps, MacBook, or amplifiers...

[JonMarsh]

Supply chain issues impacting speaker building...


This is a topic of increasing concern over the last few years, since the middle of 2020 when the COVID pandemic really started to hit home. I'm seeing a little light at the end of the tunnel, hoping it's not an oncoming freight train...

The light? Wavecor SW223BD02 is announced at PE to be available the end of December 2022 again. Could be there will be another version of Wavecor Ardent with a higher value proposition soon... midrange and tweeter candidates already selected and on hand for testing...





Might I remind those in the parts of the US that still have relatively low COVID levels now, that Germany, Austria, and the UK tend to be "canaries" in the coal mine, along with some areas in the US like LA county, and these locales are seeing high caseloads again and returns to mandatory indoor masking.


Several areas of concern and impact...

• Manufacturers hitting inflection points in their development and production for products technologies, and discontinuing older technologies popular with DIY but not for new designs by key OEMs.
  • Accuton discontinuing woofers and popular midranges (such as the C79, used in many commercial speakers and in the Wavecor Ardent), while focusing on new technologies, such as the aluminum sandwich series or 4D Direct Dome Drive Design (yes, samples on hand)
  • Many popular Scanspeak and Seas parts simply going out of stock
• Tightening economic issues resulting in current technology products being essentially discontinued for the DIY distribution channel, unless OEM level volume purchases are possible, or premium products only to be sold to OEMs. (HAH! as if!)
  • Peerless at Parts Express is a key example. Popular parts like many woofers, or the DA25TX tweeter are available only in 1,000 pc purchase.
  • Accuton diamond drivers limited to OEM channels
• Shortages of key wood products, due to general supply issues and construction activities, and more recently this year, due to geopolitical issues.
  • Continued tariffs on soft wood products from Canada
  • Since Ukraine war, baltic birch ply supply drying up due to sanctions.
• Companies that have been fairly long standing popular suppliers going out of business, sometimes just due to death of the principals involved.
  • Selah Audio
  • Erse inductors
• Rising cost of raw materials and supply chain issues for vendors delaying availability of announced or existing products
  • BlieSMa
  • PuriFi
  • Seas
  • Dayton Audio

[JonMarsh]

Another 6-1/2" two way? Really? Why on earth, why?


Ever heard the term, "gate way drug"?


well, on Mission Possible DIY, one of the early "Gate way drugs" was the Modula MTM and the Natalie P.


Hint: there are 4 configurations of PuriFi two ways under active consideration and development at this time...

[JonMarsh]

Surprise of the year...



I've wanted to update the Isiris with new drivers and new crossovers for sometime- they were originally developed in 2012-2013, and of course, with the chosen drivers, including diamond tweeters, they were pretty pretty pricey as regards basic BOM- about $10k.


But in thinking about it, and with some new driver releases from BlieSMa, PuriFi, and Dayton Audio, a performance update using the existing drivers but all new crossovers appeared to be in the realm of possibility...

But there's a difference between "Possibility" and "easy", of course.

Three major crossover iterations and a lot of thought and hair pulling and crossover part purchases later, my one test set puts a bounce in my step whenever I put some program material on it. And I'm poised in the garage workshop to modify the top module for the second cabinet set, and have the 2nd LF crossover built, and the 2nd midrange crossover well under way.


But the surprise?


It's the interest from a number of forum members to go down this path also now... you know who you are, those PM'ing me... (BTW, this year has had a big jump in the number of PMs I get- sometimes I wish they'd just post, because the info and discussion would be helpful to others, but "Private Message" means Private.)

Of course, those following that project thread are likely quite aware of Dhar's efforts, who is quite committed even though he did this before the 3rd crossover set was completed:





He tells me he's probably going to just go with a natural finish...

[theSven]

I sort of agree, while I like how everything is split up I think that really only works if we get a lot of traffic.

That is the issue I face now is how I can get more traffic to the site for people to post and interact. I've thought about getting more articles being written for content as one idea. There are many people active here that could help write some great articles on their design strategy, etc. I'm open ears to listen 😀

[technodanvan]

I'm certainly on board with increasing traffic but that is definitely not one of my skillsets, nor am I skilled enough to write useful articles, unfortunately. However, I am open to help with proofing and that sort of thing. Based on articles at other sites I feel like that is one area that isn't often implemented well. In general, I do like the changes to the site and will certainly use it for an upcoming build thread.

As far as original placement of this post goes I can't really speak much on that, but I will tag along with Jon and mention my concern mostly lies with DIY since that is where I am most likely to post.

[theSven]

I'm certainly on board with increasing traffic but that is definitely not one of my skillsets, nor am I skilled enough to write useful articles, unfortunately. However, I am open to help with proofing and that sort of thing. Based on articles at other sites I feel like that is one area that isn't often implemented well. In general, I do like the changes to the site and will certainly use it for an upcoming build thread.

As far as original placement of this post goes I can't really speak much on that, but I will tag along with Jon and mention my concern mostly lies with DIY since that is where I am most likely to post.

Thanks for the feedback 😀. I look forward to future build threads too from you!

[technodanvan]

I really, really want to make these. I have absolutely nowhere to put them though, and my queue should be considered 'full' at this point...

[theSven]

I really, really want to make these. I have absolutely nowhere to put them though, and my queue should be considered 'full' at this point...

That thought has crossed my mind numerous times! However I have to remain focused and my next project is a new center channel for the theater. What I need to consider is that if I ever move I want a big rectangle room that I can easily move speakers in an out of and store them in a room to swap out for listening 🤣. I'm looking forward to hearing what Efalegalo built once he is ready to invite for a listening session.

[JonMarsh]

That is the issue I face now is how I can get more traffic to the site for people to post and interact. I've thought about getting more articles being written for content as one idea. There are many people active here that could help write some great articles on their design strategy, etc. I'm open ears to listen 😀

Hey Sven!

I think I'm going to have to go look at the Article "item" or tool to find out just what it supports.

In the past I have written a couple of "articles", in that they were created with what you would call desktop publishing grade software and "printed" as PDFs. One was an expanded version (27 pages) of a Speaker Builder article series, (not around anymore, I think it was absorbed into AudioXpress)(CD's of back issues available) about the development of a two way 8" system ulimtately based on the HiVi M8a woofer and Seas XT25 tweeter ("Breaking with “modern conventions”- a highly musical two-way system using an eight-inch woofer") which was published as a three part article, back around 2000, due to the length of the original article. It touched on two earlier versions, and went through the design process using a number of tools from that day and age (my own MathCAD based boundary analysis program, 3D CAD modeling with AutoCAD, LspCAD for simulation design, CLIO Win for acoustic measurements using a B&K 4133 pressure zone mic that I'd had since the late 70's, publication schematics created with Eagle PCB, room position analysis using RPG Acoustics software, and it featured the use of elliptical filters not only for driver resonance notch filtering but to realize the high order crossover transfer function. The cabinet was a heavily modified one available from Madisound at that time, (easier starting point for most builders) but with full drawings included so that one could scratch build it if desired. A total of 58 figures.



It's a large PDF, nearly 50MB, so impossible to email, usually has to be hosted for download, but it can be sent via Apple Messages, if you're curious to see it. I still get requests for it now and then, not so much for the design, but I think for the design process- obviously, one might substitute more modern tools, but the thought behind the process seems to have proven useful to a lot of folks.

The other PDF article is the Modula MT MkII Guide, a PDF document explaining the design and construction of a waveguide based two way which used a heavily modified MCM waveguide with a custom interface to it for a Scanspeak D2608/9130, which was selected after evaluating quite a few tweeters and waveguide combination with the specific target of realizing tightly grouped polar response to 45 degrees and 15kHz, and 20kHz to 20 degrees, while reducing distortion in the tweeter to below the LR2/2kHz crossover point. The design was pretty successful in this regard, with the relative HD3 distortion between 250Hz and 10kHz about -60dB down, at 87 dB output. Tools used included LspCAD, Fuzzmeaure, Smith & Lawson impedance measurement, (very smooth curve, quite vacuum tube friendly). The enclosure was a Modified Parts Express model, again, easing the constructor workload.





This one is only 25 pages long.

Now, I haven't taken a look at the "Article" tool and whether or not it's suitable for the equivalent of online publishing. I should do that soon...

My thought is that it's best suited for a complete combination design study, project and build combo.

The potential drawback is that it's a lot of stuff in one place, and there is no opportunity for interactive comment and review. Topic threads like the Wavecor Ardent and the Kurosawa project (still not completed- interrupted by a host of things, like pancreatic cancer in my dearly departed!)

Now, another approach to an "Article" would just be a short app note of sorts about a specific design development, or measurement concept or construction technique. We have topic sections for those things, in some cases have had them for a while...

Another would be doing the "On the Bench and In the System" pieces more like a complete Stereophile review, say, and just publishing them as articles. That seems more amenable than many DIY efforts.

Three projects on the agenda that could be amenable to an article approach might be a couple of smaller system ideas in development, two based on a PTT6.5W04 woofer, and one based on the Accuton C168-6-890. Yeah, I know, everyone says the world doesn't need another 6-1/2" two way, and I think half the folks saying that are ones that have never attempted to design a truly superlative one.

One more that could be interesting for the article approach is the CC Supreme, as by most standards, that system will be pretty radical due to the configuration concept and the use of an asymmetrical time offset crossover that is very near minimum phase from 250Hz up.

If I would pursue any of these as articles, then I suppose I shouldn't do a stream of consciousness development project thread, but just drop it on the forum as a complete article with an accompanying thread for follow on questions. If I do this with the other larger project that I'm dancing around the development issues and "leaking" stuff into design studies, then I should probably go silent on that project, too, until it's ready.

OTOH, I think something like the modification update to the 10 year old Isiris design is fair game for a rambling project topic where we let folks see the messy process making the sausage, with all the iterations, backtracks, and head scratching that involves...


Comments?

Suggestions?


And hey, I'm just one guy- contributions that others wish to consider are certainly up to their preferences and desires, right?

[JonMarsh]

OK, did my little bit of research, I see that articles are created by up converting from an existing forum post- which means the available forum formatting tools are what is possible to use, unless one creatively cheats and creates material offline and uploads an image of the text block, for example.

That will put some constraints on what is realistically possible to do... I have no idea what the image limits are for one post with the current version of the software, but if the image is uploaded, it used to be 4. I can tell it is higher now, but don't know how high... have to check with Sven about that. I suspect it's not 39, like the shorter of my two PDFs are. And I imagine it should all be composed off line and then uploaded, as multiple work sessions and saving and editing might be a bit clumsy.

Hmmm, need to give that some thought.

[technodanvan]

I think it is common for articles to have a forum post associated with them for discussion as well. Something just linked at the end of the article? That way you can continue the conversation and address questions as they come up.

[theSven]

It would be 2 part, the article is the data published, and then you link to the forum thread for discussion. Each section of the document would make up an article and that would give us a series to read through and link back to the forum thread. The Article would allow us to organize data on this in one place to read and then discussions in the forum let us opinion and collaborate. With the search greatly updated from the latest vBulletin we would have the best of both worlds. Data to share and easily consume with discussion.

What I've started realizing since taking over this site is that most of our data is builds and design. Unlike some of the other forums that discuss products and reviews we are really focused on design and building here. HT really isn't even that popular here anymore, but I will still try to keep posting and doing things that I find interesting to share. In the end it is about the journey we want and our destination is we had fun!

[JonMarsh]

OK, I'll try that for the next projects and project builds- save stuff up until I have a solid starting article, then post that for the thread start, and elevate to an article. There are some older threads like on the Wavecor Ardents that have enough info in the first post to possibly justify a "retro fit" of that technique, just to expand the article listings. Let's see if I can find some time over the holiday break to look into that a bit, and I'll definitely reserve it for the current projects in development.

[theSven]

The DIY sub forums have now been moved out for better user experience. Apologies if the move broke any bookmarks. Now we don't have to go into the Mission Possible DIY to see all the updates, they are now all visible from the main forum page.

[JonMarsh]

Father Knows Best..

🤣

and I do like it!