impedance bridging matching circuit devices damping factor impedances dB decibel loss - There are no 4 ohm or 8 ohm amplifiers - voltage matching and bridging calculations calculation the damping - sengpielaudioChecker
 
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Voltage Bridging or impedance bridging - Zout < Zin

In electronics, audio and sound recording, only a high impedance bridging, voltage bridging,
or simply bridging connection is used, which maximizes transfer of a voltage signal to the load.

• Interconnection of two audio units •

Damping (signal loss) of an interface, when Zout and Zin meet.

Interface damping means voltage level damping compared to the open circuit case.

Z2 (Zout) is the small internal resistance (source impedance or output impedance) of the first unit
and Z1 (Zin) is the larger external resistance (load impedance, input impedance) of the following
equipment. With resistance R it is always meant the impedance Z. In recording studio technique
the voltage bridging Z1 > Z2 is used for the interconnection in general, which is a voltage divider.
This are great advantages, because it is best for the large frequency bandwidth to be transmitted
and by changing loads, by different cable lengths, and by parallel connection of several devices.
It keeps the voltage high at the input of the following gear.
The impedance matching concept Z1 = Z2 is expected to remain in telecommunications, not in audio.

Calculation of the damping bridging circuit devices damping factor - sengpielaudio

    Microphone → Microphone pre amplifier (mixer)
Mikrofon
Mikrofonvertaerker
Output impedance Zsource =   ohms   |   Input impedance Zload =   ohms
         
   Signal or load loss Δ L =   dB
   Damping factor DF =   = Zload / Zsource = Z1 / Z2
In recording studio technique the microphone Zsource (Z2) is less than 200 ohms and Zload (Z1)
of the mixer (pre-amp) is between 1000 and 2000 ohms. A voltage loss by attenuation of less
than 1 dB is acceptable in professional audio engineering.
The cable resistance (impedance) is a part of the output impedance of the amplifier. Because
Voltage at the input of the amplifier = open-circuit voltage of the source × Zload/(Zload+Zsource)

Power Amplifier     → Passive Loudspeaker
Leistungsverstärker
Passiver Lautsprecher
Output impedance Zsource =   ohms   |   Input impedance Zload =   ohms
         
   Signal or load loss Δ L =   dB
   Damping factor DF =   = Zload / Zsource = Z1 / Z2
In the audio technology even for speaker amplifiers (power amplifiers), we use only
impedance bridging (voltage bridging). The frequent call for "real" matching
Zsource = Zload is really wrong.
There is no speaker impedance matching. We got speaker impedance bridging.

 
There is no impedance matching Zout = Zin between power amplifier and loudspeakers.
 

No matching speaker impedance (load) to amplifier - No loudspeaker load matching -
Matching is a myth. We got speaker impedance bridging.

The seldom specified source resistance Z2 is hidden in the damping factor DF.
A damping factor of at least DF = 100 is entirely in order. Analog studio devices have
a source impedance Z2 of less than 40 ohms, with a load impedance of Z1 greater
than 10 kiloohms. Zsource << Zload.
Impedance matching (power matching) Z1 = Z2 on the other hand, is used in the
telecommunications and the RF technology applied to antennas.

Aha!
Notice:
There are no 4 ohm amplifiers.
There are really no 8 ohm amplifiers
for the 4 ohm or 8 ohm loudspeakers.

That is an ineradicable myth. The output impedance of the amplifier is always a
tenth or a hundredth of the value of the loudspeaker impedance. The value of
the output impedance of the amplifier
Zsource is always hidden in the damping factor DF and can easily be calculated:
Zsource = Zload / DF.     Zload is the impedance of the loudspeaker.
The cable resistance (impedance) is a part of the output impedance of the
amplifier. Because of the high voltage of the source, cable screening (shielding)
is not necessary in this case.

The typical continuous query in the forums: "Can I use 4 ohm speakers to a
6 ohms amplifier?" (See reply under "Notice".)

These issues show that there must be storytellers underway. How can we get
rid of the nonsense of 2 to 16 ohms amplifiers?
The output impedance of an amplifier Zout is always smaller than 0.5 Ohm.
Zout << Zin.

Amateurs are happy to speak of an 8-ohm amplifier, if they think not correctly
that the amplifier output should be connected to "8-ohm speakers".
Dealers use exactly these unclear expressions. In reality, the speaker
impedance curve of a loudspeaker is never a stright line.
Typical loudspeaker impedance curves vs. frequency

Impedances behave like an unloaded voltage divider. Zload = Z1 and Zsource = Z2.

Signal loss in dB: 20 log [Z1 / (Z1 + Z2)]

Damping factor: DF = Z1 / Z2

Source impedance in ohms: Z2 = Z1 / DF

Please enter two values, the third value will be calculated.

Damping factor DF:    Magic Triangle DF
Load impedance Z1 = Zload    :  ohms 
Source impedance Z2 = Zsource:  ohms 

Z1 = load impedance and Z2 = source impedance.

Calculation of the damping of impedance bridging or
power matching an interface connecting Zout and Zin

Calculations: voltage divider (potentiometer) -
damping pad - loaded and open circuit (unloaded)

Please tell your friends: There are really no 4 or 8 ohms amplifiers to match the speakers.

Interconnection of two audio units equals a circuit of a voltage divider − Z2 << Z1.

Schnittstelle Sengpielaudio

Attention: The numbering of the impedances is inversely to a voltage divider.

Spannungsteiler

The two impedances Z1 and Z2 at one device

Calculation of the damping bridging circuit devices damping factor - sengpielaudio

The damping factor is usually given as numerical value, but also in decibels.

Enter a value in the left or right box, then press the TAB bar or make
a mouse click at an empty space at the side, to get the solution.
The calculator works in both directions of the ↔ sign.

Damping factor DF as number: 
Zin / Zout		  ↔  Damping factor as dB value:
dB
Formula DF   Formula DF in dB
DF = 10 ≡ 20 dB                DF = 100 ≡ 40 dB

Calculation of the damping factor.

How do I calculate the damping factor DF for example, at 1 kHz, if neither the impedance of
the source Z2 nor the impedance of the load Z1 is known?
Allow the source to send out of a 1 kHz sine tone and measure the resulting voltage V0 at the
output without any load. Then measure at this point the voltage VL, when the load is applied.
The damping factor is:
DF = VL / (V0 − VL)

(V0 − VL) is the voltage drop by the connected load.

Calculation: Cable Length, Cable Capacitance, and Treble Loss (Cutoff Frequency)

 
The word "power amplifier" is a misnomer. Power is not really something
that can be "amplified". Voltage and current can be amplified. The term
"power amplifier" although technically incorrect has become understood
to mean an amplifier that is intended to drive a load such as a loudspeaker.
 

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