DIY Walsh driver revisited

*L* Understood completely...one gets embroiled in final assembly and the drive to hear what it sounds like that "I'll get to it...later...." takes hold. ;)

That'd be great if you could; a compression unit would at least be an interesting variant if only for the exercise and the information it could yield. That, and the lure of a driver that could handle a higher heat load from the mechanical resistance of the system.

Altie, the 'mechanical Xover' point from radial vs. pistonic is something Gary and I have kicked about previously. It's something I want to explore with different cone materials, drive types, surround materials, and the routines to mate these disparate items together.

"Adventures In Adhesives: What will survive the 1812 Overture cannons?"
That sort of thing...*L*

Pursing the Walsh patent and wading into the cone formulas within might give a clue as to when it occurs given the frequency vs. diameter vs. cone weight/mass/thickness and the cone material. Although I'd expect the formula(s) involved might incur 'high math madness'...*G*

"My little brain feels....bruised...."
YouTube

Hi, Gary and thanks for your kind comment on my bros' demise. I kept telling him that his "girth vs. diet ratio" sucked. That and a desk job vs. 'weekend warrior' physical activities wouldn't play well in the long haul. *sigh* One hates to be right about such, but...*shrug* Heart issues run in the family; occasionally one of us gets the hard lesson on such.

Glad to hear you're picking up your audio broadsword and wading back into the fray. (Evs' been 'binge-watching' "Game of Thrones", so it's been creeping into my verbations...and I'd bet the EMS crews are still torn between gunshot wounds vs. the severe mangling steel blades could create....).

Sorry 'bout That Imagery....*cringe* What a way to end a post....*L*
 
Hmm....since I'm in the midst of a 'puter build project....it occured to me that using a CPU cooling fan on certain driver types might help handle the heat generated....

I've got a couple of 'orphans' from previous builds....I wonder....*shrug*

That, and the water cooling that's employed by the 'Overclocking Twitch-game Crowd', for a more extreme solution....no pun intended....(G(
 
Grateful that by the grace of God I can post this morning.
A while back I thought I could go back to my old ways and, drink alcohol. I was wrong. Drinking got me into all kinds of trouble. I'm clean and sober one-year now. It's nice to be back.


Reading posts about attempts to extend the low freq. sound radiation from diy DML Panels got me re-interested in bending waves. People reported better results with light weight stiff materials. Some commented that it seemed counter-intuitive. There is a good animation showing the effects of bending wave radiation with respect to wave velocity (Evanescent Waves (sound radiation from a plate)).

The common cone is by it's shape much stiffer than a flat panel of the same material. This is why the humble cone has survived all these years.

I would like to see a bending wave transducer that is not omni at the high end but yet coherent at that band in the sense that Mr. L. Walsh intended. Also, a single diaphram that would produce the entire audio spectrum by one way or the other.

Now I'm rambling...
Peace
G(C)
 
Time in a Klein bottle....

Your gracious commentary and intuitive introspection has struck a resonance but, I ask for time; for I have a late night meeting to attend...

*blink*L* Like I'd take the option of saying "No, don't go. I want to bask in the afterglow of such glowing regard for my sociopathic babble that has left these huge scars in the remnants of your logical mind....*rubbing hands with evil glee*
(Now, if I can only convince people to opt in on lakefront property near Chernobyl...ever since 'Annihilation' came out....*frown*)

...and it's good to have you back. Just as it is for you to have You 'back'.

After all....
YouTube

You can go with this:
http://i.imgur.com/lrHPHMi.gif

....or you can get with that:
https://freeformapps.blob.core.wind.../300/61f0a08e-9e9a-4e96-851d-27b0f5bdce24.jpg

Anyway...congratulations on Your Year. Now, keep it up. ;)

Back to the subject @ hand....*S*

Low fq from DMLs' shouldn't be surprising, just as one shouldn't expect a dome tweeter to handle 20hz or an 18" woofer to go to 20Khz. The physics involved doesn't make sense. I admire the 'single source' speaker crowd who feel that the proper 8" can 'do it all', but it's taking the tech to an extreme and introducing 'coloration' that really can't be avoided...IMHO.

(I'm NOT interested in a 'flame war' here. If 'You can go with that', Fine. I'd rather 'fit the shoe to the foot' as opposed to foot binding or ballet 'on pointe' stances...)

On a tech level, the original Walsh cone was genius, but pushed the level of fabrication of a cone that could recreate the span of fq of 'typical' reproduction to the limits of the time and what could be practically made.

DML's are dipoles. End of story. It makes sense that light yet stiff panels work the best, as excitation of the mass and weight of the material will effect the fq response. My imagination of a DML trying to recreate 20hz would be analogous to a leaf in a 20mph wind. Control of that with edge damping would surely effect high fq in some fashion.

Much in the same fashion that speaker design in general has opted for multiple radiators reproducing a semi-specific band of fq, I feel drawn to a 3 way approach.

Leave the bass to a sub (or subs) that have the bandwidth to extend Up to where pistonic motion begins to 'fade'. And bass fq is omni by nature; watch the shock wave from an explosion. It's not beaming, y'all.

Mid-range to a cone/driver assembly that begins where the sub(s) hand off to the mids and fade at the high fq that give one the 'sizzle' of the cymbals; that 'felt as well as heard' impression that only exists at a 'live' concert, or preferably at a small venue....

Omnis can do this. 'Naturally'.

Yes, you Have to properly 'set up' your space to do this. The 'direct radiator' crowd is already deep into such, so WTF is so different about it.

Any form of extremism does have a 'cost'. And besides, we've got access to room eq software and equipment of late that goes about 'what it does' without much distortion. So there...*G*

What remains is to make it all robust enough to keep your brother-in-law from blowing it all up when he decides to see if it can crack the plaster on the wall behind it...

This all stems from an interest in the theoretical 'point source radiator'; anyone who has witnessed a plasma flame 'speak' or 'sing' to you can attest to how erie it is.

The closest analog to this is some of the commentary that I've read regarding the MBL omnis. One account noted that it was if 'the speakers seemed to turn to look at you.'

David/Magnasanti has been deep into a DIY project to create a pair; I stand amazed at his progress, which makes my efforts look like a VW 'bug' next to a Ferrari F40. But one does what one can do...

(Hi David. *G* Yes, it IS that extreme. I am in awe, and can't wait. ;)...)

We shouldn't have to sit rooted in a chair.
 
....pardon if I rant 'n rave on occasion. Today's been the 1st 'day off' in nearly a month of non-stop work, travel, hotel life, the death of an dear friend, a tree smashing into the restroom of our shop (fortunately, no one was on the toilet), and the general intra- and interpersonal stress that accompanies all of the above....

...and today, I get to see This.

YouTube

Now.

This is a bit 'out there'....even in my reality...such as it is.

I can almost relate to the 'guy' in the chair....as for his 'fans', No, I don't think that of Anyone who's reading this.....

...at least, while I'm awake. ;) *L*
 
....and then he woke up, discovering that he'd ate his pillow. ;) Hi. *L*

The only thing I can relate that little bit of video is P.Floyd's "Comfortably Numb". But the symbolism? :boggled:

At least the soundtrack doesn't confuse the issue any further...*L* But I'd follow 'the cowboy' at a comfortable distance, just in case.

So, wuzzup 'n howu been? Back in KY, trying to get over this park...everything that seems likely to become a problem does, or takes an inordinate amount of time. That, and the weather continues to get in the way.

Highly off-subject, but seems to be par for the course....
 
...and some things stick in your head...

...like this....

YouTube

(Ignore the video, just play it....a mantra of sorts....)

Back from KY excursion 2...another short one to follow; undesired but contracts is contracts. Launching into a week of too much in too short of time that includes a speed tour to SFO/OAK for a too brief apparition appearance @ a memorial for a very dear friend who stepped off this mortal and ignoble coil...

YouTube

I met Phyllis long before I met my spouse. Always a fixture in my life; Ev met, knew, and found a good friend in her as well. I'll get to meet others I've known only referred to, and re-greet her sister who've I only met once a very long time ago....

Strangers with a touchstone in common...*s*

Meanwhile, back on the raunch....

I'm technically going into a version of 'semi-retirement'. I've become a bit too 'fragile' for the wear 'n tear of installations.
I bruise too easily.
If 'damaged', I bleed too well. Not surprising; I take anti-coagulants and thinners. I Do clot reasonably quickly, but in the interval it's unnerving for others to watch...and basically annoying to yers truly...*shrug*G*
..and I have a habit of getting 'involved' anyway... ;)

So, I get to revert to being a 'wildfire containment specialist' *L*; called in when drawings and discussions fail to gell....

Oh, well. Been there, done that, got the memorial T-shirt, shredded it doing the same thing on another catastrophe.

We're booked into Fall. There's other 'potentials' that stretch into Spring '20 that beckon. I've got a home to create in some fashion in that midst.

And then there's my Walshs'....

I'll be damned if I ignore all I've done up to now to let it lay and disperse.

"Get Busy Child". Damned straight. Stand By.

Target:
Midwest Audiofests' Open Unlimited Speaker Design Competition 7/'20

I'd like to show the gathered 'something completely different' for a change.

Maybe a 'surround version' with a sub in my hotel room for the Really Curious/Interested. *G*

BYOWhatever...;)
 
I'd like to do that, but it's highly 'schedule dependent' at this point 3.5 weeks away. We're very busy since it's 'high season' for playground fab & installs. A nice place to be, since it's how we make $. Not so good for extracurricular stuff....

IF I can break free, it'd be for an 'overnight speed tour': drive up day before the speaker contest, spend a day, then leave. Likely spend some $ on stuff Ev normally questions my sanity (of which there's not much left Anyway), trolling the booths and schmoozing with the attendi...

It'd be fun. I'll pencil it in on the dance card, but can't ink it in for now. Likely I'd know almost literally a day or 2 before, and I'll have to talk Extremely Fast to Ev to pull it off, sleep in the car, have a bout of record rainfall, eat 'track food'....

Let's see what shakes out....;) A deal if it goes...and I like to what to expect in the future. *S* And it'd be great to see you IRL....

That's a long bike ride, though....;)
 
My latest Walsh design

Hi,
I did promise to share a little bit of my latest design.
I’ve published it on youtube, check it out.
Thomas

YouTube
 

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*L* I go away for awhile, and y'all get busy....That's TERRIFIC, Thomas! Amazing work, and I'm sure the YT vids' sound track doesn't do it justice....
All CF? Sure looks like it...maybe a little tricky to move, and the cat has been banished... ;) And nothing like a lathe and a router to move things along.

Like your glue jig for the cone seams....I might 'borrow' that concept from you.... ;)

So, got the 2nd one in progress?
 
My new Walsh design

I’ve included the main patents that I have used as inspiration.
It’s intresting to note that it’s quite old stuff...
It seems that they where more innovative back in the day!
Diffraction is a major issue with the original design both from the driver/magnet and from the box. The research paper describes this.
I’m using a commercial exciter as you can see in the Product spec, Price approx. 40$.
I Will include some measurements as soon as I can find them in the archive.
The sound recording in the youtube is made with a mobile phone.

Thomas