Technics - SB-C600-K Bookshelf Speaker System (Pair)

A coaxial two-way standmount with the tweeter sitting in the acoustic centre of the woofer — both drivers radiating from one point, in aluminium, behind a shaped port borrowed from aircraft wing design. Sold as a pair, in black.

A conventional two-way speaker has its tweeter above its woofer, which means the two drivers are in different places. At the crossover frequency, where both are contributing, the distance from each to your ear differs, and that difference changes as you move your head. It is the reason so many speakers have one narrow spot where the image snaps into focus.

A coaxial driver removes the problem by putting the tweeter in the middle of the woofer, so both radiate from the same point. Technics calls this their Coaxial 2-way design, and adds a Linear Phase Plug to align the arrival times of the two outputs and a Smooth Flow Diaphragm — a shallow cone profile — to keep the woofer cone from reflecting the tweeter’s output back at you. Both diaphragms are alumite-treated aluminium.

The port is shaped using what Technics describes as an airflow control method taken from aircraft wing design, to keep air moving through it without turbulence. Anyone who has heard a reflex port chuffing on a bass transient will understand why that is worth engineering.

This is a 4Ω speaker of modest sensitivity — 83dB at 2.83V or 80dB at one watt — and Technics recommends 40 to 120 watts behind it. Do not under-power it. The crossover is at 2kHz.

One honest word about the published frequency response. Technics quotes 40Hz to 100kHz, but the tolerance on that figure is −10dB, which is an unusually loose window — a speaker can be 10dB down and still be inside a spec written that way. It tells you where the output eventually stops rather than where it is flat, and Technics publishes no tighter in-band figure. We would rather point that out than let the numbers do work they cannot support. Come and listen to them; they are considerably better than that spec makes them sound.

Features

• Coaxial two-way driver — tweeter mounted in the acoustic centre of the woofer for point-source radiation
• 150mm aluminium woofer and 25mm aluminium dome tweeter, both alumite-treated
• Linear Phase Plug time-aligning the two drivers
• Smooth Flow Diaphragm shallow cone profile to reduce reflections off the woofer
• Smooth Flow Port shaped by aircraft-wing airflow principles
• Balanced Driver Mount Architecture baffle, optimised by computer-aided engineering
• 2kHz crossover
• Magnetically attached grilles included
• Sold as a pair, with two speaker cables in the box

Specifications

• Type: Two-way, two-speaker bass reflex standmount loudspeaker with a coaxial driver
• Sold as: A pair. Technics’ US page states two speakers are included, and two speaker cables are supplied
• Drivers: One 150mm (6″) cone woofer with a 25mm (1″) dome tweeter mounted coaxially in its centre. Both diaphragms are alumite-treated aluminium
• Driver design: Technics’ Coaxial 2-way. The tweeter sits in the acoustic centre of the woofer so both drivers radiate from a single point. A Linear Phase Plug aligns the arrival time of the two outputs and a Smooth Flow Diaphragm — a shallow cone profile — reduces reflection of tweeter output off the woofer cone
• Enclosure: Bass reflex, front-ported. Technics’ Smooth Flow Port is shaped using an airflow control method they describe as taken from aircraft wing design, to reduce turbulence
• Cabinet material: Not published
• Bracing: Technics describes a Balanced Driver Mount Architecture baffle optimised by computer-aided engineering for low resonance and high rigidity, with vent holes for airflow around the baffle. No separate internal bracing structure is named for this model
• Frequency response: 40Hz–100kHz at −10dB. Read that tolerance carefully: −10dB is a very loose window and tells you where output ceases rather than where it is flat. Technics publishes no tighter in-band figure for this speaker
• Nominal impedance: 4Ω
• Minimum impedance: Not published
• Sensitivity: 83dB at 2.83V/m, or 80dB at 1W/m. Technics publishes both figures on the same sheet. At 4Ω nominal, 2.83V is two watts rather than one, so the 3dB difference between the two is arithmetically consistent — though Technics does not state that they derive from a single measurement
• Recommended amplifier power: 40–120W. Rated input power 60W, maximum input power 120W, tested to IEC 60268-5 short-term maximum
• Crossover frequency: 2kHz
• Crossover slope: Not published
• Binding posts: Brass, screw type. Technics does not state whether these are five-way binding posts or a screw-clamp terminal
• Bi-wiring: Not supported and not mentioned in any Technics material for this model
• Dimensions: 173 x 293 x 283 mm (W x H x D), including the 8mm grille and 15mm terminals
• Weight: Approximately 6.3kg per speaker (approximately 14 lbs)
• Grilles: Included, attached by four magnets each, with no required orientation
• Country of manufacture: Not published. No Made in statement appears on Technics’ UK or US pages or in the owner’s manual
• Warranty: Panasonic administers Technics warranty in the United States and the term varies by model rather than by product category. The SB-C600 is listed in Technics’ own US warranty table at three years parts and three years labour. Technics states that product registration is not required and does not extend coverage. A dated sales receipt is required, coverage runs to the original purchaser, and the product must be purchased and serviced in the United States. Non-rechargeable batteries, antennas and cosmetic cabinet parts are excluded.