All language subtitles for S16E07 - Audio Vacuum Tubes; Light Bars; Wood Model Aircraft; Metal Snare Drums (1080p AMZN WEB-DL x265 Garshasp)_track3_[eng]

Narrator: when it comes
To sound quality,

Audiophiles swear
By amplifiers which contain

Vacuum tubes to boost and modify
The electrical signal.

They were the norm until
Transistors came along

In the 1950s.

Many audio enthusiasts still
Prefer tube sound,

Which they find warmer, richer,
And more natural.

[ mid-tempo music plays ]

Once standard in radios,
Phonographs, and televisions,

Today you see vacuum tubes only

In very high-end
Audio equipment.

They come in an array of models
Designed to perform specific

Sound-enhancing tasks.

Technicians at this czech
Factory first wind wire

A precise number of revolutions

With a very specific degree
Of tension.

Then they clean the surface and
Weld it to a support structure.

This completes the grid, one of
The tube's main components.

Next, technicians take
The second main component,

The cathode,
And insert it into the grid.

When the sound signal
Enters the tube,

The cathode produces
A flow of electrons.

The grid controls that flow

As it travels to the third
Main component, the anode.

The anode's top secret
Black coating

Increases the effect of
The electrons hitting it,

Causing the anode and cathode
To have two different voltages,

Both of which are greater than
That of the original signal.

This makes the signal larger
And more powerful,

Meaning it amplifies the sound.

With those three components now
Assembled into one unit,

The inside structure of the tube
Is complete.

Now for the bulb,
Which will encase the unit.

A glass blower skillfully crafts

It out of hard,
Laboratory-grade glass.

Using a high-temperature torch
And glass-making tools,

He melts the open end
And seals it off.

Then he blows in a bit of air

To shape the end into an evenly
Rounded dome.

Now he mounts the bulb on a
Lathe to complete the shaping.

Keeping the glass evenly heated,

He blows in just enough
Air pressure to keep the bulb

From collapsing inward.

When the glass reaches
Just the right temperature,

A die presses against it,
Setting the final shape.

Next, they mount a glass collar

Over copper wires clamped
Into a motorized vice,

Then insert a glass straw called
An evacuation port.

As the vise rotates, they heat

The collar uniformly
With stationary torches.

Using a handheld torch,

They remove any stretches or
Runs in the softening glass.

When the time is right,
They activate a die

To press the glass
Into the final shape.

This completes the stem on which

The tube's inside
Structure sits.

The wires protruding
From the top of the stem

Connect to the
Structure's terminals.

Now they put this assembled unit
On a turntable

And center the bulb over it.

As the turntable revolves, they
Heat the bottom of the bulb.

As the glass melts,
They press it inward,

Fusing it to the stem.

They remove the excess glass
And continue heating

To ensure the bottom
Is fully sealed.

Next, they prepare
To suction out the air.

This step is critical
To the tube's performance,

Because air molecules
Hinder the flow of electrons.

Technicians fuse the tube's
Evacuation port

To the glass evacuation line
Of a vacuum pump.

The pump then extracts the air
Through the port.

At the same time, they heat
The tube in a pull-down oven.

This increases pressure inside
The tube,

Creating a stronger vacuum.

Next, they run an inductive
Heater over the tube.

This dislodges damaging
Impurities,

Enabling the vacuum pump
To draw them out.

They target the stem area
With a second inductive heater

To draw particles called ions
Onto the glass permanently

So that they can't later
Damage the tube.

Finally, they connect
The protruding wires

To a plastic plug-in base.

There are subtle technical
Differences between tubes

Of the same model.

So the factory tests each tube,

Then matches pairs with similar
Performance features.

This ensures they'll amplify
Sound evenly.

Narrator: a light bar is that
Strip of flashing lights on top

Of a police car
Or emergency vehicle.

The lights are
High-output l.E.D.S,

Far more efficient and
Durable than incandescent

Or quartz halogen bulbs
Or strobe tubes.

The mounting system is designed

To withstand emergency
High-speed driving.

[ siren wails ]

The l.E.D.S are grouped by color
Within a module.

Modules can be arranged
In any configuration

On the light-bar base.

The base mounts
To the vehicle's roof

Via straps made of
High-strength stainless steel.

Those straps begin
As flat pieces,

Laser cut to
A starting shape.

A 50-ton forming press bends
Them to the final shape,

Which fits the exact contour
Of the vehicle's doorjamb.

The light bar's white light
Modules fasten onto the base

With the aluminum brackets
This worker is assembling.

These brackets also help draw

Out the heat the lights
Generate.

This is critical, because if
L.E.D.S overheat, they burn out.

The base is made
Of extruded aluminum.

This computer-controlled laser,
Working on six bases at a time,

Cuts out holes for venting
And cables.

The light bar has two cables --

One running power
From the vehicle's battery

To the light bar
And another connecting

Control switches
On the dashboard

To the light bar's
Electronic control board.

An automatic machine measures
And cuts the required length

Of each cable, then strips off
A specific amount

Of the pvc outer jacket
At both ends.

This exposes three wires,

Two of which are insulated
And inside a foil wrap.

After stripping off the foil,

An automatic stripping machine
Removes some insulation,

Bearing the tin-coated
Copper wire within.

Workers put contacts
Onto two of those wires --

The ground and the power --

Then press the contacts
On securely

With a crimping device.

Next, they connect a terminal
To the third wire,

The shield drain.

This wire reduces electronic
Interference

From sources like
The police radio.

Now for the l.E.D.
Light modules,

The main component of
Which is a reflector.

They put the reflector's plastic
Body into the sealed chamber

Of a metalizing machine.

The machine then releases
Argon gas

While applying hundreds of
Volts of electricity

To a solid piece of aluminum.

This vaporizes the metal
Into tiny particles,

Which a vacuum draws
Onto the plastic body

In an ultra-thin reflective
Coating.

To broaden the horizontal range
Of the reflection,

Workers install a device called
A collimator.

Then they take an l.E.D. Light,

Put an electric insulator
On the back of it...

And mount it inside a housing
That's specifically designed

To remove heat from the l.E.D.S.

Then they install these
Assembled light components

In the reflector...

Install the connector that plugs
Into the wire harness

That leads
To the control board...

...And test the finished module.

To assemble the light bar,

They slide the control board
Onto the base,

Plug in the control cable
That connects the board

To the dashboard switches,

Install the power cable
That runs

From the vehicle's battery
To the light bar,

And the wiring connecting
The lights to the board.

After mounting the white light
Modules on the brackets

And securing them to the base,

Workers take the colored
L.E.D. Modules

And slide them onto
The tracks on the base.

They make the internal
Connections

To the control board,

Then plug each module into
The control board harnesses.

After testing to make sure
Everything works properly,

It's just a matter of encasing
The modules,

Starting with an aluminum top,

Then slide on transparent
Plastic lenses

With divider gaskets in between

To prevent rain from penetrating
And shorting out the light.

A cap closes up each end.

After a final round of testing,

The light bar is ready to hit
The roof and the road.

Narrator: flying a wood model
Aircraft is a way to experience

The adventure of flight
On a small scale.

But there's a lot to do
Before takeoff.

These miniature planes
Usually come in kits

That can take dozens of hours
To piece together.

But, of course, that's just part
Of the fun.

Wood model planes are part
Of aviation history.

The first real flying machines
Were made of wood,

And soon
After their invention,

People began building miniature
Wood replicas in kit form.

Today modern manufacturing
Techniques take the concept

To a whole new level.

Production begins with blocks of
Wood that circle on a system

Of conveyors.

Each time around, a long blade
Slices away a thin piece.

They transfer the sheets of wood
To a table

That moves in a
Computer-choreographed sequence

While lasers overhead make cuts.

This computerized system
Produces parts

That will fit
Together perfectly,

No matter
How intricate the design.

To assemble the kit at home,

The modeler extracts
The precut parts.

He then builds the fuselage
Right on top of the plans

In order to follow them
To the letter.

After the fuselage
Has been assembled,

He focuses on the wings.

He braces the main spar
With numerous ribs

To create a
Cross-sectional air foil

That will generate lift.

He then glues the wings' leading
Edge to the framework.

The framework is very similar to
That of full-sized wooden wings

Built in the early days
Of flight.

It's made mainly
Of tropical balsa,

A wood that's both lightweight
And exceptionally strong.

The modeler joins the two wings.

The tongue of one fits into the
Laser-cut slot of another.

This joint will later be glued
To reinforce it.

He demonstrates the next step
Using the wing of another model.

He drapes plastic film
Over the wing's skeleton.

He tacks the plastic to it

And smoothes out ripples
And bubbles.

He then heat-shrinks the plastic

To give the model aircraft
Its tight skin.

Of course, there's no need
For a paint job

Because the plastic is tinted.

Finally, he confirms
That it's drum tight.

Back on the production line,

They're now winding wire
To produce a spring.

This spring is a shock absorber

For the plane's
Front landing gear.

With that complete,

They now position a sheet
Of preheated plastic

Above six molds
Of wheel covers.

He activates a vacuum that pulls
The plastic over the molds.

In seconds, it cools and
Solidifies into the shape

Of the wheel covers,
Called pants.

With the wheel pants assembled
To the craft,

The modeler now installs
The two-stroked

Alcohol-burning engine
In the front compartment.

He attaches the muffler
To the engine's crank case.

He then secures the spinner's
Back plate and propeller

Onto the engine's driveshaft
With a washer and bolt.

This assembly will have to
Withstand the force

Of the spinning propeller,
So he tightens it to the max.

And this model plane is now
Ready for flight.

Incredibly, it started out
As a bunch of parts in a box,

But they all come together

In the hands of
A skillful modeler.

Of course, a good set of
Instructions is essential.

Assembling each model
Can take up to 50 hours.

We've just shown the highlights.

The payoff comes
When the operator

Manipulates the
Transmitter joystick

And the parts of the plane move
Right on cue.

From fighter planes and biplanes
To civilian aircraft

And extreme
Aerobatic machines,

When it comes to these
Historical replicas,

The sky really is the limit.

Narrator: the sound of a
Snare drum is unmistakable --

A sharp rattle with
A somewhat tinny resonance.

What produces this
Distinctive sound?

It's a vibrating set of wires
Called the snare wire

Stretched across the bottom
Of the drum.

The snare drum is the center
Of the drum kit.

[ drum music plays ]

The circular frame of a
Snare drum, called the shell,

Can be made of either wood
Or metal.

Metal shells produce a sharp,
Loud, and more brilliant sound.

The metal this german
Drum company uses

Is known as bell bronze,

Which is approximately
78% copper and 22% tin.

Workers first glue together
A three-part mold.

It's made of a sand
And chemical mixture

Because sand can withstand
The temperature

Of the hot molten metal.

The glue sets in about half
An hour, and the mold is ready.

They steady it
With heavy steel plates,

Then scoop a bucket full
Of bell bronze

From the furnace
And pour it in.

It took four hours at
2,300 degrees fahrenheit

To melt the metal,

But just a few seconds
For it to solidify

Inside the mold cavity.

They let the casting cool
For a couple of hours,

Then break the sand mold
To extract it.

They clean off the loose sand
With a wire brush,

Then ship the shell
To the drum factory,

Where its first stop is onto
An automated lathe.

As the lathe spins, a cutter
Skims off a thin layer of metal,

Making the shell's exterior
Surface clean and smooth.

Next, a computer-guided drilling
Machine bores 47 holes

For various components,

Including fittings that hold
And adjust

The drum heads and a vent hole

That increases
The drum's volume.

Then the machine changes the
Drilling tool for a milling tool

And makes two recessed areas
Called snare beds

In the shell's bottom edge.

The drill left rough edges,

So they clean and smooth
The holes

With a small grinding tool.

Then they manually sand
The snare beds.

Next, they sand the shell's
Outside surface,

First with a rough
Abrasive belt,

Then with a fine one.

This leaves the metal shiny
And silky smooth.

Now they sand the inside surface
By hand.

Then they spray it with
Bronze-colored lacquer

To give the metal an even color
And prevent tarnishing.

They taped over the holes
To keep the colored lacquer

From hitting the outside
Surface.

Now they remove the tape
And spray the outside

With transparent lacquer,

Which allows the natural color
Of the metal to show through.

25 minutes in an oven hardens

The lacquer into
A super durable finish.

Then final assembly begins,
Starting with the tension lugs,

The fittings that hold
And adjust the tension

Of the drum heads.

Next comes the action strainer,

The mechanism the drummer flips
Up or down

To activate and deactivate
The snare sound.

The top drum head is made of
A strong polyester material.

A chrome-plated metal hoop will
Hold the head to the shell.

To tune the drum to a higher
Or lower pitch,

The drummer tightens or loosens
The screws

To increase or decrease tension.

Drumhead tension
Determines pitch.

The bottom drumhead is made
Of clear polyester film.

It's much thinner
Than the top drumhead

To enable the snare wire
To respond faster.

That snare wire is made of

Multiple strands of stainless
Steel, brass, or copper wire.

They stretch it across
The bottom head,

Laying each end
On a snare bed.

They attach the ends with nylon
Cords to the action strainer

On one side and to a part called
The butt end on the other.

To play the drum
With the snare sound,

The drummer simply pulls up

On the action strainer's
Handle.

Every drum undergoes a final
Inspection, then tuning,

And a thorough performance test.

[ drumming ]

Talk about ending with a bang.

[ drum music plays ]

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