Simple Surround Sound Speaker Circuit

This circuit shows you how to improve your surround sound system without needing fancy new speakers.

It uses a technique called the Hafler circuit invented by David Hafler that simply uses a knob and speaker placement to make the sound coming from the front and back speakers sound more balanced.

What is a Surround Sound Speaker Circuit:

An electrical circuit called a surround sound circuit is made to improve audio playing by producing a 3D and immersive sound experience, particularly in multichannel audio systems like home theaters.

The circuit is in charge of sending audio signals to several speakers arranged in a deliberate manner all around a listening area.

This gives the sound depth and directionality.

Working of Surround Sound Speaker Circuit:

Parts List:

Setting up the Hafler circuit for easy use is simple.

The rear left and right speakers receive identical L-R signals.

If their efficiency is so low that they are not sufficiently loud with most audio content you can omit R1.

Using just one rear speaker is adequate provided its impedance is 8 ohms or higher preventing strain on the amplifier.

Ideally, position it in the middle rear facing upward or toward the back wall to enhance reflective rebound.

How to Build a Surround Sound Speaker Circuit:

Building a surround sound circuits involves some technical knowledge and skills in electronics.

Connect Hafler Circuit:

• Wire the left and right backside speakers as per the Hafler configuration.
• Include potentiometer R1 according to the circuit design.

Amplifier Connection:

• Connect the surround sound configuration circuit to the amplifier.
• Ensure proper matching of positive and negative terminals.

Rear Speaker Setup:

• Connect the rear end speaker to the amplifier.
• Place the rear speaker in the middle rear, facing upward or toward the back wall.

Optional On/Off Switch:

• If desired, install an on or off switch to control the rear channels.

What is a Enhanced Surround Sound Speaker Circuit:

An Enhanced Surround Sound Circuit typically refers to an audio circuit that goes beyond basic surround sound setups to provide a more sophisticated and optimized audio experience

Working of Enhanced Surround Sound Speaker Circuit:

Parts List:

The circuit above offers an enhanced surround sound effect compared to the previous one and may be more effective for rock than jazz music.

Adjust potentiometer R1 and R2 simultaneously to achieve the correct front to rear balance.

The settings of R1 and R2 may slightly depend on the listeners seating position.

Fine tune potentiometer R3 by listening to the audio to achieve a subtle blending of the front L and R signals into the rear speakers.

If desired, install an on or off switch at X to eliminate music blending across the rear channels.

If your amplifier has an A and B switch for an additional pair of speakers, connect the rear speaker circuit (a) or (b) directly to the positive B terminals.

This enables easy on off switching of the rear channels.

Formulas:

David Hafler is well known for his contributions to the field of high fidelity audio systems and audio amplification.

An amplifier is usually used to drive several speakers in a surround sound speaker circuit, ensuring that the speakers are correctly balanced and that the overall sound quality is maintained.

Calculating Power:

To determine how much electricity each speaker will need:

P = VRMS²​​ / R

where,

• P is watts of power
• VRMS voltage across the speaker
• R is the speakers resistance, often 4 or 8Ω (as per the amplifier).

Balance Adjustment Formula:

If you want to balance two channels using the potentiometer:

V_{out ​}= V_in​ × R_pot​​ / R_pot​ + R_fixed​

where,

• Vout is the amplifiers output voltage
• Vin is the voltage input from the audio source
• Potentiometer resistance is represented by Rpot.
• R fixed If a resistor is employed its value is fixed

Impedance Matching:

Make sure the amplifier is seeing the proper impedance load when using multiple speakers.

For concurrent speakers:

1 / Rtotal ​= 1 / R​1​+1​ / R2​+…..

For speakers in series:

Rtotal​ = R1 ​+ R2​ + …..

Make sure the total impedance fits the amplifiers requirements.

This streamlined method gives you a basic idea of how to mix the music across numerous speakers and set up a surround sound system.

Additional factors like crossover networks, equalizers and sophisticated amplifier topologies could be needed for a comprehensive and high quality system.

How to Build Enhanced Surround Sound Speaker Circuit:

Modify Hafler Configuration:

• Upgrade the Hafler Configuration based on the design specified for enhanced surround sound.

Adjust potentiometers:

• Simultaneously tweak potentiometer R1 and R2 to achieve the desired front to rear balance.
• Fine tune potentiometer R3 by listening to the audio for blending of front L and R signals into the rear speakers.

Optional On or Off Switch:

• If not already present, consider installing an on or off switch for greater control over music blending across the rear channels.

Connection to Amplifier :

• If your amplifier has an A and B switch connect the rear speaker circuit directly to the positive B terminals for easy on off switching.

Conclusion:

Always follow safety guidelines and double check your wiring to prevent any damage to components.

If you are not comfortable with electronics, consider seeking assistance from a knowledgeable individual or consulting professional services for the assembly and setup of your surround sound system.

References:

Two channel audio surround sound circuit

Hafler circuit