Oehlbach Bi-Tech 4.4 L (2 x 3m)

Powering a speaker with two amplification channels, one for bass and the other for midrange and treble, requires four conductors per side instead of two. Oehlbach supplies this connection ready to plug in, with conductors of different materials and cross-sectional areas according to the part of the spectrum they carry, and factory-fitted spade connectors at both ends. All that remains is to choose the right length and tighten the binding posts.

Two copper cross-sections according to the frequency band

Each cable in the pair actually combines two independent connections. Bass travels through two 4 mm² oxygen-free copper (OFC) conductors, a generous cross-section with good reason: the bass driver draws most of the current supplied by the amplifier. Over 5 m, the resistance of such a connection remains just a few hundredths of an ohm, including the outgoing and return paths, well below a speaker’s impedance (4 to 8 Ω), and this margin is particularly beneficial for longer runs and low-impedance speakers. Midrange and treble travel through two 2.5 mm² silver-plated oxygen-free copper (SPC) conductors, a surface treatment Oehlbach reserves for this part of the spectrum because high frequencies flow more near the conductor’s surface, a phenomenon known as the skin effect. At audible frequencies, this effect remains modest in fine strands, and the difference between silver and copper is slight. The principle of separation, however, is sound: each signal path has its own pair of conductors, with no shared return path. The flexible plastic insulation, blue against a copper-coloured background, keeps the cable flexible despite its overall cross-section.

Connecting a speaker for bi-amplification

The Bi-Tech 4.4 L is used with a speaker equipped with two pairs of binding posts, one pair for bass and one for midrange and treble. These two pairs are connected as standard by jumpers (strips or short cables), which must be removed before connecting the four spade connectors; otherwise, the two amplifier outputs would be connected to each other. At the electronics end, the four conductors connect to two separate pairs of speaker outputs: two stereo amplifiers, one per frequency band or one per speaker, or a home cinema amplifier capable of reassigning some of its channels to bi-amplification. The speaker’s passive crossover continues to distribute frequencies between the drivers; each amplification channel simply works with a smaller load, with bass no longer modulating the power supply of the channel handling midrange and treble. The audible benefit depends on the speaker and amplifiers used, and is more noticeable with current-demanding speakers than with easy-to-drive models. Oehlbach specifies a recommended amplifier power of up to 400 W.

Fusion spade connectors with gold-plated contacts

Each cable ends in four Fusion spade connectors at each end, with 24-carat gold-plated contacts. The spade slides under the tightening collar of a screw-type binding post and provides a broad contact area once tightened, making it a connection that remains stable over time. Gold is not there to improve conductivity: it protects the contact from oxidation, whereas bare wire eventually darkens and loses connection quality. Factory assembly also prevents stray strands from protruding from the binding post and potentially touching the neighbouring terminal. The spade has one limitation: it is not suitable for the spring terminals found on some entry-level speakers and electronics. The cable is made in Germany and covered by a 30-year manufacturer’s warranty.

Choose the length before ordering

The Bi-Tech 4.4 L is available in 2, 3, 4 and 5 m lengths, referring to the length of each cable in the pair. As the connectors are factory-fitted, the cable cannot be shortened without losing the spade connectors: it is best to measure the actual route, along the skirting boards and around the furniture, then add a little slack so the speakers can be moved a few centimetres during adjustment. Keeping the same length on both sides simplifies installation, even though the sound response does not depend on it over these distances. Any excess should be stored in wide loops behind the furniture rather than tightly coiled.

Technical Specifications

Construction and Design

• Optimized hybrid design
  • 2 x 2.5 mm² silver-plated oxygen-free copper (SPC) for midrange and treble
  • 2 x 4 mm² oxygen-free copper (OFC) for bass
• Premium insulation
  • Highly flexible for easy installation
  • Durable protection against wear
  • Effective interference suppression

Electrical Specifications

• Signal type: analog audio
• Signal direction: input / output
• Maximum supported power: up to 400 W (350 W according to another source, to be confirmed with final specification)
• Bi-amped design for demanding high-fidelity systems

Physical Characteristics

• Cable geometry: round
• Total cross-section: 2 x 2.5 mm² (SPC) + 2 x 4 mm² (OFC)
• Insulation material: flexible plastic
• Color: blue / copper

Connectors

• 4 x Fusion Oehlbach cable lugs per pair
• 24-carat gold-plated contacts
• Reliable, lossless transmission
• Robust and durable contacts

Package Contents

• 1 pair of pre-assembled cables
• 4 x cable lugs already mounted on each end (total: 8 lugs)

General Information

• Lossless transmission of low frequencies
• Excellent detail reproduction in midrange and treble
• Highly flexible and easy to install
• Manufacturer warranty: 30 years