Wednesday, May 20, 2015

Midrange Corner Horn - Fitting The Driver Pair


The lower driver flange is fastened to the horn throat after marking and countersinking for two mounting fasteners and after applying flexible adhesive caulk to the horn throat perimeter.  The square access hole was enlarged to provide access to the lower horn throat.
 
Midrange Corner Horn - Lower Driver
Midrange Corner Horn - Lower Driver
The lower horn throat flange is now fastened on over the adhesive


Midrange Corner Horn - Lower Driver
Midrange Corner Horn - Lower Driver
For the upper driver, a little material has to be removed with a very sharp wood chisel before the flange can be glued and fastened.



Midrange Corner Horn - Upper Driver
Midrange Corner Horn - Upper Driver


Midrange Corner Horn - Upper Driver
Midrange Corner Horn - Upper Driver

Midrange Corner Horn - Upper Driver
Midrange Corner Horn - Upper Driver
 One of the screw fasteners interferes with fasteners already in the wood so a weight is placed over the flange to hold it in place while the adhesive dries.


Midrange Corner Horn - Upper Driver
Midrange Corner Horn - Upper Driver
 The upper and lower drivers are mounted on their respective flanges and wired in phase and in parallel.  In addition, a Magnavox tweeter horn is connected across the driver terminals and protected by a 10uF series capacitor.

Midrange Corner Horn - Both Drivers Installed And Wired With Horn Tweeter
Midrange Corner Horn - Both Drivers Installed And Wired With Horn Tweeter


Midrange Corner Horn - Both Drivers Installed And Wired With Horn Tweeter
Midrange Corner Horn - Both Drivers Installed And Wired With Horn Tweeter

Midrange Corner Horn - Upper Driver Installed - Close-Up
Midrange Corner Horn - Upper Driver Installed - Close-Up
Here is a view of the midrange corner horn and tweeter set up for testing.


Midrange Corner Horn And Tweeter Horn Set Up For Testing
Midrange Corner Horn And Tweeter Horn Set Up For Testing
There is a pretty smooth transition between the midrange and tweeter at about 2500Hz.  The midrange response extends to a little below 300Hz.  With both midrange drivers connected, the efficiency of the corner midrange horn appears to be comparable with the efficiency of the Magnavox tweeter horn.  The DC impedance of the two midrange drivers in parallel is 4 Ohms.

A Fully Horn-Loaded Loudspeaker From Found Materials

The prototype for A Fully Horn-Loaded Loudspeaker From Found Materials is now substantially complete and performs magnificently.  The most recent testing included listening to Virgil Fox playing the Aeolian-Skinner Organ in The Riverside Church, New York City.  The 1994 CD, The Art Of Virgil Fox - Vol. 1, is a reissue of recordings made during 1959-1961.

A Fully Horn-Loaded Loudspeaker From Found Materials
A Fully Horn-Loaded Loudspeaker From Found Materials

You can follow the development of this project on this blog by clicking on entries in the right-hand column under "Blog Archive".



Tuesday, May 19, 2015

Corner Midrange Horn Adhesive Drying

Today, the corner midrange horn center flare assembly is further fitted and provided with a wood plug to close the opening adjacent to the mouth ends of the two small horns constructed yesterday.
Here is a view of the center flare assembly with the wood plug positioned over a gap.


Corner Midrange Horn - Wood Plug Over Gap
Corner Midrange Horn - Wood Plug Over Gap

I applied flexible adhesive caulk to the joints in the horn flares.  The adhesive will dry overnight.


Corner Midrange Horn - Adhesive Applied To Joints
Corner Midrange Horn - Adhesive Applied To Joints


Corner Midrange Horn - Adhesive Applied To Joints
Corner Midrange Horn - Adhesive Applied To Joints
I conducted a test of the frequency response by holding a small square baffle with attached small two-inch driver taken from a Cambridge Soundworks computer sound system over one of the throats.  Driven by a sine wave generator, at least to my ear, the horn appears to have useful output from about 300Hz to about 3000Hz.



Monday, May 18, 2015

Progress On The Corner Midrange Horn

The side wall flares will be connected to a pair of eight-inch long horns positioned in the corner between the walls.  Here are the six ribs in the process of being shaped with coarse sandpaper and block.  The clamp holds them in position so they will come out about the same size and shape.

Corner Midrange Horn - Shaping Six Ribs
Corner Midrange Horn - Shaping Six Ribs


Corner Midrange Horn - Shaping Six Ribs
Corner Midrange Horn - Shaping Six Ribs
 Here are two of the ribs in position in the a corner.
Corner Midrange Horn - Two Ribs In Position
 Here is one rib with the curved panel partly attached.  This shows the kerfs cut into the panel to make bending easier and more uniform.

Corner Midrange Horn - Curved Panel Attached
Corner Midrange Horn - Curved Panel Attached
 Now the curved panel is attached to both ribs with a side panel also in position.

Corner Midrange Horn - Partial Assembly Of One Horn
Corner Midrange Horn - Partial Assembly Of One Horn


Corner Midrange Horn - Partial Assembly Of One Horn
Corner Midrange Horn - Partial Assembly Of One Horn
 The first horn is assembled and the second horn will be put together after cutting a square hole in the "floor" for access to the throat.

Corner Midrange Horn - Second Horn Assembly With Throat Access
Corner Midrange Horn - Second Horn Assembly With Throat Access
Both horns are in position.

Corner Midrange Horn - Both Horns In Position
Corner Midrange Horn - Both Horns In Position
 Now, it is necessary to remove some wood from the center flare assembly ribs so they will fit into the space between the small horns now in position.

Corner Midrange Horn - Removing Wood From Ribs With Saw
Corner Midrange Horn - Removing Wood From Ribs With Saw
Corner Midrange Horn - Removing Wood From Ribs With Plane
Corner Midrange Horn - Removing Wood From Ribs With Plane

 Here is the center flare assembly in position.  More fitting is necessary to bring the joints in the side wall flares together for a closer fit.

Corner Midrange Horn - Center Flare Assembly In Position
Corner Midrange Horn - Center Flare Assembly In Position
 Here is a close-up of the throat of one of the horn assemblies.  You can see where the ribs are located and how they provide the proper curve for bending the panels.  Later on, a throat flange will be glued over the throat opening so a small two-inch speaker with back chamber can be mounted on each of the horn throats.


Corner Midrange Horn - Throat Of Horn Assembly
Corner Midrange Horn - Throat Of Horn Assembly
Here is a view of the other horn assembly throat.
Corner Midrange Horn - Throat Of Horn Assembly
Corner Midrange Horn - Throat Of Horn Assembly
 After fitting is complete, all the joints will be sealed with a flexible caulk.
















Friday, May 1, 2015

Sound Transformer Plays Some Music

Here are a few videos of Sound Transformer playing some music.

A funny song by Louis Armstrong and Bing Crosby:
https://www.youtube.com/watch?v=N24K4I94Wfc

Here is John Coltrane:
https://youtu.be/jfMZFww1IX4

Herbie Hancock:
https://youtu.be/a0mjgrqQlAE

And something brassy:
https://youtu.be/N24K4I94Wfc

Brubeck star dusting:
https://youtu.be/8q1iFOS-B5I

More Coltrane:
https://youtu.be/yMFUVmQ_xzM

The Horseshoe Crabs:
https://youtu.be/h5mZ2yG2DMc

Phil and Friends:
https://youtu.be/frferndcSdM

Medeski Martin and Wood:
https://youtu.be/2O7gB_S5XR4