SP150 Bass Loudspeaker

Bass Loudspeaker with White Marble Plinth and Top.

Introduction to the SP150 Bass Loudspeaker

The SP150 extends the bass response of a speaker system down to 30 Hz. Designed to compliment the SP62 series loudspeakers it may also be used in any system that needs bass extension. With 'fast low bass' it is particularly suitable for use with electrostatic panel speakers.

The SP150 has been designed for high quality sound reproduction and is of a sealed box construction. The compact enclosure uses two 150 mm metal cone drivers mounted face to face in an isobarik configuration. The SP150 covers the audio spectrum from 30 Hz to 10 KHz.

The much higher frequency response from the 26 gram cones is necessary to accurately reproduce the low octaves and match the tonal characteristics of the main speakers. There are no tuned ports and so all low frequency signals are reproduced cleanly.

The SP150 is normally assembled with the drive units down at floor level, but may be re-assembled with the drive units at the top. A much higher cross-over point can then be selected. with a SP62 series speaker placed on the top.

The SP150 cabinet is made from hardwood panels, not MDF or other composites.

Internally the SP150 walls are heavily damped to minimise vibration and the enclosed volume is filled with a mixture of long hair black sheep wool and acoustic wadding. The two drivers are wired with heavy gauge copper cable to gold plated terminals which have provision for cables up to 7.5 mm in diameter.

The SP150 as shown has a polished hardwood cabinet with White Carrara marble top and plinth.


  • Fast response from lightweight cones accurately integrates with main speakers.
  • Sealed enclosure design for controlled roll-off and resonant free sound.
  • Isobarik configuration for low distortion.
  • Dense enclosure material for high acoustic mass damping and low resonance.
  • Drivers connect directly to external amplifier.
  • Made in hardwood with white Carrara marble top and plinth to add mass though axis of movement.


 Drive Units: Bandor-150

See www.bandor.com for further details.

SP-150 Specification

Cones 150 mm anodised aluminium, 2 off.
Moving mass 26 gm per driver.
Frequency range < 30 Hz to 10 KHz.
Voice coil/former 29 mm 8 ohm aluminium .
Power handling 200 watts RMS.
Internal wiring 54/0.18 mm (1.25 mm2) Linear Crystal - Oxygen Free Copper.
Terminals Gold plated, cable to 7.5 mm O.D.
  Enclosure: 260 mm square by 750 mm high (less feet/cones).
  Plinth: 320 mm square footprint.
Weight 32 Kg (approx).
Enclosure material
  Standard: Polished hardwood panels; with white marble Top-plate and Plinth.
  Option: Other Marble or Granite Top-plate and Plinth.
Colour / finish
  Standard: Polished wood and natural stone.
  Option: Hardwood veneers; natural colour and pattern.

Life expectancy: 100 years plus for the cabinet (the drive units may need refurbishing before this).


For anyone who may be interested in making a (pair of) loudspeakers to this design here are scans of my original drawings - made on an Apple SE computer with a StyleWriter printer.

150 dpi GIF file drawings (A4) for printing.

Design by: Susan Parker, MIEE.

Please note: Personal Use Only

Email: susan@audiophonics.com

All design and other information, drawings and images on this website are
Copyright 1992-2010 Susan Parker MIET (unless otherwise credited).

These designs and other information may be used to construct systems specifically for personal NON commercial use only.

N.B. Personal liability disclaimer applies - see T&C.