Thiel Owners

I had a pair of the Adcom 565s and they were terrible sounding and lacked dynamic scale and punch. Up and left my crib soon after..Saw several pairs of Thiels unwound by the use or misuse of Adcom amps. Sonically not much of an improvement over Denon receivers they could play louder but sounded similar. TomD

The 2 large conical shapes, one smaller than the other, by appearance don’t seem to align symmetrically which I think is a good thing. The stepped alignment of the cone segments themselves would reduce a polarity of shear from traveling and returning back into the cone and again becoming a part of the next signal. Purify drivers have a stepped surround which I believe serves a similar though unintended purpose for reducing shear wave interference. A shear wave can only travel thru solids and travels in 2 directions until it collides into another and splits again and again. That is why the grill frame material and shape is important and can be heard when the style is changed, or when the grille is removed. This wave action and their collisions is generally not well understood but is used in the study of seismology and should be used in acoustic design and implementation... TomD

If a crossover is mounted to the floor base of the cabinet it will be closer to mechanical ground and then resonace will be more easily drained. Plus the mounting of the crossover to the backwall is like a backboard on a basketball goal. Bouncey bounce. TomD

I took my Dunlavy SC 4s outboard 20 yrs ago as is my current build. Crossovers also sound better when mounted on brass Audiopoints this can be done in the cabinet or outside . Noticeable ..TomD

I removed the steel door that covers my breaker panel box which is located in my audio room. With 2 friends present I did a door on door off  listening test. Obvvious improvement every time with panel off. Steel will alter the flux field as a signal travels a copper wire. Same as I found replacing steel fasteners with brass holding drivers ,tweeters ,crossovers and circuit board  fasteners.. Any ferrous material will bend or alter a signal path . Generates interfering energy. TomD

Tom - my thoughts are that having  a steel grill even a mesh  in front of a driver with a very powerfull neo magnetic field will alter the inductance of the coil as it moves between the magnetic field . The steel in front will bend the intended field. TomD

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Cowhorn, if we get together I have an extra pair of Sistrum/Live platforms I can bring along. They work wonders under everything that has motion, electrical or mechanical. Not many of us locals involved in quality audio ..darn shame. Tom

Tom  Thiel, 

Are you stating you would mount the crossover board up right on edge? If that is correct this would expose the circuit board direct in line to the most significant mechanical impact from any open back driver in the cabinet. Visual would be a basketball hitting the back board. Damping would reduce but will also increase  the resonace retention time of any aquired energy which can become part of the orginal intended signal. My methods are much different  1 of which allows for external adjustemt of the resonance point of the internally loaded circuit board. Resonace will be drained thru the bottom mounting method and coupled internally to cabinet bottom and externally  to the mass of the floor. This feature benefit can also be done on a preferred external mounting method. I think we have discussed  these methods in the past. I know your project is to be simple and of a high value. You may want to offer up these significant options for users who want to max out resonance control. There is also an option to externally resonance tune the woofer to the backside of the cabinet. This entails a brass connecting rod and a special tuning bolt turned by hand .Like you would tune a stand up bass. Significant audible upgrade. I know your trying to increase open surface area to benefit heat dissapation..Resonance tuning also reduces thermal runaway as the heat has a method to transfer as does resonance.. TomD

Hello Agburns, 

There were 2 Toms working at the main Louisville store at the same time. I was and still am the shorter 1. The other Tom was tall with very curly hair. He had a very animated style while mine was considered more laid back  TomD

Agreed upon. When going outboard with a Dunlavy modified crossover there was a gain in performance even more so when placed on a resonance grounding platform. Not a so called isolation platform as those trap and slow burn the exit of resonance. You want a nice quiet exit thru reactive materials with the proper conductive geometry as a tour guide to the exit. TomD

There is a method of material coupling where the collection of resonant energy is transferred to a large disc of the same material effectively increasing the surface area many times. And if you have 3 or 4 these devices then you effectively have the same shelf or floor surface under each and every component set up this way including the speakers. It works. TomD

My external crossovers have 1 single  input pair from the amp and 2 output pairs from the board to the 2pr of terminals mounted to the back of the speaker cabinet.

The leads from amp to crossover are 6 ft. The leads from the crossover to the speaker cabinet are 30in. The speakers rest on Sistrum stands the crossovers  on Sistrum platforms all direct coupled to the floor for maximum resonance grounding. TomD

Oh, the wire in use is the same all the way thru in the amp and into the drivers.. TomD

I have been using brass fasteners for many years.

Here is a useful video as to the how and why. I know he moved back to Canada. TomD. https://youtu.be/piWxZK_9hyQ

Tom Thiel you have sparked a light ball in my brain. Eddy currents are another descriptive term that falls into the file cabinet of interfering energy. Same goes for shear wave interference and boundary interference. Right angles are a simple eyeball example..to be continued.. TomD

Hello Anthony, Glad to know we are both still around.

The points I supplied you were most likely Audiopoints a product line that I have long supported and do till this day. If the points are attached to a metal platform you have a Sistrum platform now called Rythm platform.  Both have brass points with a select geometry facing up and down attached thru the channels of the platform The company name is now Live-Vibe Audio. Let's keep in touch. TomD

Speaking of fans my Music Fan reduces speaker baffle and room boundary effects. Makes for more focus within a larger soundstage. Bass has greater articulation like applying a giant comb.

I would expect Doug and Tom’s film approach could've be applied to room surfaces as well as many different brands of speaker baffles. Congratulations to Team Thiel and all their cooperative and diligent work!

I am working on an applied formula that has a negative Poissons ratio and when applied to surfaces reduces their shear velocity. The closer a material’s shear velocity is to the speed of sound is in air the better the transfer of musical energy. TomD

Congratulations to Team Thiel!

Tom Thiel did you or your brother Jim ever study or observe any benefit of the structural placement of driver's or port tubes as they relate to laminar flow inside of a speaker cabinet. Are there any published studies on turbulence generated by internal cabinet shape or attached support obstacles? TomD

Thanks Tom.

I was thinking of the internal shape of the cabinet and bracing as well as the shape that is displaced by any port of any shape or length Those right angles of corners, braces and oddly shaped ports must generate turbulence and interference and blowback that impede airflow of the intended cone motion. Maybe I will make a clear top panel and place a smoke device inside so I can view the turbulence generated by all the contained boundaries. A passive radiator or two maybe the cleaner way to travel especially inside a poured or cast cabinet. TomD

Any input or updates for types of wire used inside the speaker cabinet? Any experimentation with routing or any added material for resonance control of internal speaker wire? TomD

Tom

Based on what I vision a solid core wire would be more coherent than a stranded cable. A solid core will have 1 single path vs a multitude of paths of many fine wires as a group..resulting in group delay? I sold and owned Dunlavy speakers. He had his own wire that he used and appeared to be multi strand like and offset like twin lead antenna wire.

Of course Dunlavy had patents on antenna design that were used in the military.

Again you make me think of the 48 strand 8 gauge Litz.inductors used on my ribbon Tweeter. Said to have a bandwidth of nearly 40k. Other styles are said to have much lower bandwidth which may be fine for the frequency range of any given woofer or midrange. But the counter of that is any wire touching another insulated wire wound or twisted in any geometry has to interact with the intimate wire next to it  I try to use the same group type of everything thing to maintain symmetry of sound and coherence..such as wire caps and inductors. Nice to hear a choir to speak with one great voice.

That's the goal for me and most others who visit here.

TomD