Oehlbach Bi-Tech 4.4 L (2 x 5m)

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-sections according to the part of the spectrum they carry, and factory-fitted spade terminals 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 that is justified: the bass driver demands 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 both outward and return paths, well below a speaker’s impedance (4 to 8 Ω), and this margin is particularly beneficial for long runs and low-impedance speakers. Midrange and treble travel through two 2.5 mm² silver-plated oxygen-free copper (SPC) conductors, a surface treatment that Oehlbach reserves for this part of the spectrum because high frequencies tend to travel closer to the conductor’s surface, a phenomenon known as the skin effect. At audible frequencies, this effect remains modest in thin strands, and the difference between silver and copper is small. The separation principle, however, is sound: each channel has its own pair of conductors, with no shared return path. The flexible plastic insulation, blue against a copper-coloured background, keeps the cable supple despite its total cross-section.

Connecting a speaker for bi-amping

The Bi-Tech 4.4 L is used with a speaker equipped with two sets of binding posts, one pair for bass and one pair for midrange and treble. These two pairs are linked by default with jumpers (bars or short cables), which must be removed before connecting the four spade terminals; 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-amping. The speaker’s passive crossover continues to distribute frequencies between the drivers; each amplification channel simply works with a reduced load, with bass no longer modulating the power supply of the channel handling midrange and treble. The listening benefit depends on the speakers and amplifiers used, and is more noticeable with current-hungry speakers than with models that are easy to drive. Oehlbach specifies a recommended amplification power of up to 400 W.

Fusion spade terminals with gold-plated contacts

Each cable has four Fusion spade terminals at each end, with 24-carat gold-plated contacts. The spade slides under the tightening collar of a screw binding post and provides a large contact area once tightened, making it a connection that remains stable over time. Gold does not 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 compatible with 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 terminations are factory-fitted, the cable cannot be shortened without losing the spade terminals: it is best to measure the actual route, along the skirting boards and around the furniture, then add a little extra length to allow the speakers to be moved a few centimetres during adjustment. Keeping both sides the same length simplifies installation, even though the sound response does not depend on it over these distances. Excess cable 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-amplified 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 side (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