Improving lateral consistency

The latest amplifier technology and acoustical components have been used to ensure the most accurate sound reproduction possible. Robust drivers, a rock-solid cabinet, and carefully designed ports guarantee a tight, articulate, and distortion-free low frequency reproduction, even at high replay levels. Using the sum output, Plane Wave Bass Array™ (PWBA™) techniques acoustically improves lateral consistency in the listening area. The bass extends down to 18 Hz.

Flexible mounting options

The KH 870 subwoofer is designed to complement Neumann's extensive range of monitors, and can be used on its own, or daisy-chained to make larger systems capable of higher SPL. The KH 810 can be used in music, broadcast, and post production studios for tracking, mixing, and mastering. The cabinet can be positioned next to a wall or flush mounted into a wall due to the front mounted port, and can be mixed freely in multichannel systems with other loudspeakers from Neumann's range.

Applications

• Bass extension for loudspeakers down to 18 Hz
• Increasing the maximum SPL of loudspeakers by up to 8 dB
• Decreasing harmonic and intermodulation distortion of loudspeakers
• Reproducing the LFE channel
• Reproducing the “Sub” signal of a bass managed multichannel source
• Making a Plane Wave Bass Array™ system
• Working as an extension for KH line subwoofer systems

• Computer mechanically modeled cabinet design using Low resonance Integral Molding™ (LRIM™) materials

  • Wooden cabinet with a tough painted finish and high density rubber isolating feet
  • Excellent self-damping properties leading to minimal cabinet resonances
  • No standing wave resonances inside cabinet
  • Reduced cabinet resonances

  (2)
  In-house modelled long-throw composite sandwich cone bass driver with Extremely Linear Force Factor™ (ELFF™), magnetic shielding, flow optimized die cast basket and robust built-in grille

  • Damping of break up modes brings low distortion at high sound levels
  • Linear pistonic motor gives a very low harmonic distortion even at high excursions
  • Reduced air noise and improved rocking modes
  • Grille protects against mechanical damage

  (3)
  Large high-capacity flow-optimized bass reflex ports

  • Fast bass transient response
  • Reduced bass compression at high output levels
  • Can be flush mounted

  (4)
  XLR electronically balanced analogue inputs and outputs

  • Standard interfacing to professional equipment
  • Daisy chain output for subwoofer arrays

  7.1 High Definition Bass Management

  • Compatible with all systems from mono to 3D
  • Bypassable 4th order 80 Hz active crossover for maximum compatibility with consumer reproduction systems
  • Allows main loudspeakers to play louder and with lower distortion

  (5)
  Remote control

  • NRC 1 and SEA 1 hardware remote control
  • RS-232 control possible

  (6)
  LFE gain

  • 0 and +10 dB

  Four routing modes

  • LFE to subwoofer and left/right
  • LFE to subwoofer only up to 80 Hz
  • LFE to subwoofer only up to 120 Hz
  • LFE to subwoofer with no filtering – for daisy chaining subwoofers and external signal processing systems

  (7)
  Wide range input gain and output level controls

  • Easier interfacing with signal sources

  8-position phase control (with built in test tone), continuous low cut control and parametric equalizer

  • More control in diverse acoustical environments
  • Parametric equalizer is bypassable if not needed

  (8)
  Bass Management controls

  • Bypassable
  • Independent control of bass management bypass for front and back channels
  • System volume control on/off

  (9)
  Universal switched-mode power supply (100 … 240 V)

  • One version works in any country and robust to poor quality mains supply
  • Electronics can be remotely powered on with two modes of operation (0 V and 12 V trigger)

  (10)
  Ground lift

  • Reduced noise in electrically noisy environments and over-comes ground loops

  (11)
  Sum output

  • Larger systems and Plane Wave Bass Arrays™ maybe constructed using the Sum output

  (12)
  Low heat dissipation amplifiers with large headroom and overheat limiting

  • Improved transient response
  • Assured reliability and safety

  Separate fast acting thermo limiter to protect the voice coil and power amplifier

  • Soft clip and excursion limiters
  • Increases system reliability
  • Allows extraction of the maximum performance from the system

  (13)
  Installation flexibility

  • Remoteable electronics (REK 3) for ease of installation, less cabling, and convenience of use

  • Free field frequency response ±6 dB	17 … 600 Hz
    Free field frequency response ±3 dB	18 … 300 Hz
    Reproduction accuracy between 50 Hz and 100 Hz: 100%, 80%, 50% of subwoofers produced	±1.20; ±0.54; ±0.28 dB
    Self-generated noise at 10 cm (with input gain set to 100 dB SPL for 0 dBu)	<20 dB(A) SPL
    Sine wave output with a THD < 0.5 % at 1 m in half space	95 dB SPL (>40 Hz)
    Bass capability: Max. SPL in half space at 3% THD at 1m (averaged between 50 Hz and 100 Hz)	116.7 dB SPL
    Max. long term SPL with pink noise at 2.3 m, in typical listening conditions (single / pair full range)	118 dB SPL
    Analog input(s)	8 x XLR: analog electronically balanced
    Analog input impedance	>13k Ohms
    Max. input level	+19 dBu
    Common mode rejection ratio (CMRR)	> 56 dB @ 15 kHz
    Crosstalk (1 kHz), level matching	-95 dB; ±0.1  dB
    Volume control	NRC 1 hardware remote or RS-232
    Volume control range; resolution	118 dB; 0.25 dB
    Analog dynamic range; THD+N	119 dB(A); <0.001% (-100 dB)
    Signal routing modes	LFE 80+re-routing; LFE 80 Hz; LFE 120 Hz; Wide
    LFE Gain	0 / +10 dB
    Analog output(s)	8 x XLR; analog electronically balanced
    Input gain control (sensitivity)	+2 ... -12 dB
    Output level control (output level in 1 m based on 0 dBu input level)	100; 114 dB SPL
    Controller design	Analog, active
    Crossover frequency	80 Hz
    Crossover slope	24 dB/oct; 4th order
    Equalization: Low cut	30 Hz; 0 … -12 dB
    Equalization: Parametric EQ: Gain	+4 ... -12 dB
    Equalization: Parametric EQ: Frequency	Bypass; 20 ... 120 Hz
    Equalization: Parametric EQ: Q	1 ... 8
    Phase	0; 45; 90; 135 and 0/180 deg
    Protection circuitry	Peak and thermo limiters
    Infrasonic filter: frequency; slope	6.5 Hz; 12 dB/oct.
    Remote control	RJ45 connector: Via NRC1 remote control (optional): volume for all channels; bass management on/off; LFE gain 0/10 dB.Via RS-232: more parameters remote controllable
    Display: On; Normal Operation	Red LED
    Display: Limit / Clip / Errors / Protection /Boot Mute / Shut Down Mute	Red LED
    Display: Bass Management on	Green LED
    Output power woofer amplifier (THD+N with limiter deactivated: 10%)	400 W
    Output power woofer amplifier (THD+N with limiter deactivated: 0.1%)	320 W
    Mains Power Supply: input voltage; frequency	220-240 / 100-120 V (switchable); 50/60 Hz
    Power consumption (230 V / 100 V): Idle	25 W
    Power consumption (230 V / 100 V): Full output	550 W
    Cabinet material	Wood cabinet, aluminum electronics panel
    Cabinet surface finish; color (front / back)	Painted; metallic anthracite (RAL 7021) / black (RAL 9005)
    Operating conditions	+10° C to +40° C (+50° F to +104° F); <90% RH, non-condensing
    Transport/storage conditions	-25° C to +70° C (-13° F to 158° F); <90% RH; non-condensing
    Woofer	2 x 265 mm (10") with magnetic shielding and protecting black metal grille
    Mounting points	35 mm flange on top panel
    Product dimensions (height x width x depth)	735 x 330 x 645 mm (28.9" x 13" x 25.4")
    External net volume	156 liters
    Product weight	47.1 kg (103 lbs 13 oz)
    Cabinet weight when electronics remote located	45.5 kg (100 lbs 5 oz)
    Packed dimensions (height x width x depth), mm (inches)	860 x 470 x 770 mm (33 7/8" x 18 1/2" x 30 3/8")
    Packed weight	54.3 kg (119 lbs 11 oz)
    Packed cube	0.311 m³

    Diagrams

    KH 870 with O 410 Frequency Response

    

    Parametric - EQ

    

    Lowcut

    

    KH 870 with O 410, Group Delay

    

    Maximum SPL at 1m (Red: 3% THD, Blue: 1% THD)

    

    O 410 with KH 870 Maximum SPL at 1 m (Red: 3% THD, Blue: 1% THD)

    

    Harmonic Distortion at 95 dB SP (Blue: THD, Red: 2nd harmonic, Green: 3rd harmonic)