Ohm Walsh Micro Talls: who's actually heard 'em?

peterr53,

Thanks for working on my speakers.
They sound a lot better now.

There is no doubt that you have the most powerful subwoofers I have ever heard.

The most illustrative test we did on my 2.2000s was monitoring the frequenct response in real time while we were listening to some of my music. Most of the sound was below 5K Hz! It showed me how importatnt the midrange is to good sound reproduction. Basically, 95% of audible music is between 30 HZ and 10K Hz. So, having a 20K tweeter doesn't accomplish much.

I also witnessed the 2.5K roll off of the main Ohm speaker. This isn't a bad thing as long as the tweeter picks up the slack.

In the future, I look forward to reporting on Peter's Walsh 5 upgrade. For now, he is using my 2.2000s as stand-ins and I appreciate his feedback and development work on them. At least the tweeters are pointed in the right direction now.

Good evening everyone....

Should be in Sweden, but decided to wait a few weeks as my dad is out of the hospital and doing a little better.

It's always great to see Tate, and we got some time to chat and listen to
some great music. As for the 4/5000's I got so far as cutting the bottoms out, strip out all the braces etc. 

So the BIG question is were am I going from here? 
Slapping in some braces and call it the day will not happen on my watch
so it will be something wild and esoteric (within reason). I need to dampen down the cabinet as it rings like a cheap bell. So the walls will have a multi layer construction (CLD) with a mix of soft pliable glue/butyl rubber layers, and epoxy infused cement. All the mixes and layer choices will depend on how much I can move the frequency band to a desired point were it will sound proper. The top part of the speaker will have a constraint layer of (see image) aluminum, steel, butyl, and 3/4" thick layer
of aluminum (I might change my mind about that) the Walsh driver will be counter sunk in the plate. This next part is a trick one as I don't want to use bolts/screws, I want to use neodymium magnets on the cabinet side
and on the Walsh driver side sandwiched between some low shore hardness iso-gel. The idea is to totally isolate the driver from the chassis. 
I finally figured out the bracing system. It will be a mix of a special plastic
with constraint layers of a harder layer on each side with butyl rubber sandwiched in between. The deal is that it's very easy to damp to a certain level, but at some point the vibrations have to be dissipated somehow. Kind of how you would damp a tuning fork with your finger.

The bottom will have a familiar pattern of a skyline diffuser to try to mitigate reflexions back to the driver cone. To tune the port I will have a sliding tube system that can get tuned on the fly from outside the speaker.

I attached a few images showing a waterfall plot of some different materials for bracing (guess which one I'm using).

Plywood with a butyl rubber layer, I knocked on the butyl for both samples.
Plastic composite butyl rubber
Empty cabinet
Upper metal rings on a CF plate I might use
https://www.flickr.com/photos/147883144@N08/shares/89Wt27
 

So finally passport in hand and a schedule of departure.....

Today I was testing some glues, in this case a glue for the end of the 
cross braces. Super glue sucked, but I'll try a different kind tomorrow. Gorilla glue was promising but not perfect, but the winner
was the lowly hotmelt glue....lol 
More testing to tomorrow as I will most likely use 3-4 different kinds depending on material or if there's a sheer force in the part.

Anyway more to come soon....🇸🇪

Greetings from a very rainy and windy SoCal... :(

Yesterday was incredible here, warm, sunny, and blue skies, perfect for working on speakers...lol
The speakers were cleaned from old  hotmelt, staples and assorted old crap, but it's amazing that 40 year old particleboard is still staying together and doesn't crumble.

I made a test patch of a mixed materials including non drying clay, butyl, cement board, neoprene drenched in a glue that dries but stays gummy and a commercial vinyl tile that is very dense  and non resonant. To top of the sandwich I added a 1" layer of felt. The size of the sandwich is 7"x 12" and the final weight was about 4 lbs
.
The mix of materials makes for a non-reasonance composite.
 But  I am considering adding a thin layer of lead on the speaker walls before the the cement board to make it even less resonant. The final weight of the wall material will be in the 75lbs😜 range including the lead layer.

These measurements will change as it doesn't include cross bracing, final top and bottom caps.
I do hope to keep the final weight of the speaker below 150lbs without the base that weighs somewhere north of 65lbs.

The cabinets were never torn down as far as I can tell, so I re-glued
all the corners with gorilla urethane glue, interesting stuff that gets activated with a damp surface or a spray of water.

The first layers of metal plates making up the speaker attachment 
where glued and clamped in yesterday. Basically I took one steel plate attached it on the surface below the original attachment surface. The other layer above the that plate is  a 1/4" cork layer a 3/4" layer of particle board, butyl and another 1/4" steel plate. All the layers where bonded together with Gorrila glue. To top of the cabinet / Walsh attachment two more layers of 1/8" aluminum plates will be bonded with more high viscosity glue and then bolted together with counter sunk bolts at each corner. The baffle for the Walsh driver will be about 2 3/4" thick when done.....wow

I have questioned the switches in previous posts, so yesterday I removed the the back plate of the switch so I could get to the guts of the part...!! Yes my concerns were all found true, the switching armature is so thin so it's a wonder that they don't blow up all the time,  plus it looks like they're made from steel (I will check with a magnet next time I'm out in the shop).

Thats today's post.......🇸🇪

Another sucky day in SoCal, cold but no rain here in Lakewood....

Woke up up with another palm tree broken at the root, this is the second one in less than
two weeks.
Figure a few hours in cold shop would do me good, and by the end of the day I had basically installed all the metal plates in the upper part of the cabinet.
All plates have either a layer of butyl or a mix of butyl and neoprene rubber and to hold it all together I'm using Gorilla glue. This glue is pretty amazing stuff wet it and it slowly filling any voids and giving the layer a cushion to float on. 
After the layers were glued together I figured I would do a knock test to see how the cabinet
respond to being shored up in a proper way. 
Check out the before and after sound and vibration test...
https://www.flickr.com/photos/147883144@N08/shares/0L3pb1

I should have some more stuff tomorrow..........🇸🇪