Magneplanar DWM Woofer Instruction Manual

Table of Contents

  1. Introduction/General Description
  2. Carton Contents
  3. Packaging
  4. Installation and Hookup
  5. Placement
  6. Phasing
  7. Bass Attenuation
  8. Fine-tuning the bass and midbass of floor-standing models with the DWM
  9. Service and Shipping
  10. Specifications

  1. Introduction/General Description

    The Magneplanar DWM is a dipole, thin-film planar/magnetic woofer which is a derivative of the MG 20.1 DiPlanar woofer technology. The DWM can be driven simultaneously by 2 separate amplifiers (typically the front left and right channels). A built-in crossover provides a high-pass output for use with "small" Magneplanars.

  2. Carton Contents

    • 1 - DWM Loudspeaker with base
    • 1 - Magnepan "Shaped" Pink Noise CD Test Disk
    • 2- 2 ohm, 25 watt resistors
    • 1 - Hex Wrench
    • 1 - Speaker Logo
    • 1 - Owner's Manual

  3. Packaging

    Save all packaging. The DWM can be shipped safely only in the original packaging. Should you discard it, packaging is available from Magnepan.

  4. Installation and Hookup

    Install the base with the 2 screws. It may be necessary to realign the dowel nut in the speaker before installing the base and screws.

    Connect the speaker wire from the amplifier to the amplifier input on the DWM, observing polarity. Connect the "small" Magneplanar to the output of the DWM, observing polarity. (Note- There are no left or right inputs or outputs on the DWM Woofer.)

  5. Placement

    As a general rule, dipole speakers produce the deepest and most linear bass and midbass when positioned approximately 4-6 feet from the front wall or 1/3 of the way into a room. This rule may conflict with the necessity to have correct time alignment with the "small" Maggies. Since rooms vary greatly, these setup instructions are principles of operation and specific and detailed instructions are not possible. Magnepan and our dealers can provide advice on the specifics of your room.

    It is generally understood that placement of subwoofers is very flexible. While subwoofers do offer more latitude in placement due to the long wavelengths at low frequencies, technically, there is an ideal place in a given room for optimum subwoofer performance. The DWM is a woofer, not a subwoofer. And the superior performance of the DWM, as compared to a subwoofer, is due in part, to extremely wide bandwidth (flat to 5 kHz). The DWM can seamlessly cross over at a higher frequency to any of the limited bandwidth "Maggie" models. However, the higher crossover points require proper time alignment to achieve the most seamless blend between the DWM and the limited bandwidth Magneplanar. Therefore, the DWM should be equi-distance from the listener to the limited bandwidth Magneplanar. Minor adjustments from that position are often necessary for "fine tuning" as described under "Phasing" below.

    The DWM should be oriented so it is perpendicular to the side wall and playing down the length of the room as shown in Fig. 1 below.

    The DWM will give the lowest frequency response if a boundary is used to reduce dipole cancellation of bass frequencies. A placement along a wall or next to a cabinet or piece of furniture will reduce dipole cancellation.

    Fig. 1

  6. Phasing

    The Magnepan Pink Noise CD Test Disk included with your DWM can be used to determine if the DWM is in ACOUSTICAL phase with your limited bandwidth Magneplanar. The test CD has a 9 db peak at 80-100 Hz that draws attention to the frequencies which will be depressed in an out-of-phase condition. Place the DWM next to your limited bandwidth Magneplanar and change the phase. (It is much easier to detect an out-of-phase condition when the "small" speaker is physically next to the woofer.) Since the DWM is a dipole woofer, the easiest way to determine if the DWM is in-phase is by simply turning the woofer around (180 degrees). The speakers are in-phase when the peak is the loudest.

    The high output of the DWM is in positive polarity with respect to the bass. In this particular case, do not think that the plus output of the DWM must go to the plus terminal of the "small" speaker. Depending upon the "small" speaker to be used with the DWM, it may be necessary to operate the "small" speaker with the phase reversed for smooth frequency response through the crossover region. If you are uncertain if the acoustical phase is correct, a technique which can help is by leaning over and positioning your head between the Magneplanar Woofer and the "small" Magneplanar as shown in Fig. 2 below. The left and right ears are equi-distance to the respective speakers. High frequencies will appear to be up and low frequencies will appear to be down. Midbass frequencies, if in phase, will appear to be in the middle (and louder).

    Depending upon the location of the DWM with respect to the limited bandwidth Magneplanar, the DWM might be 90 degrees out of phase with the "small" Magneplanar and changing the phase does not make a noticeable difference in the loudness of the pink noise peak. It may be necessary to move the DWM with respect to the Magneplanar to achieve a better acoustical in-phase condition.

    Fig. 2

  7. Bass Attenuation

    If it is necessary to reduce the output of the DWM, remove the Bass Attenuator jumper and insert a 25 watt (or higher wattage) resistor. Typically, 2-4 ohms is sufficient for most installations where bass reduction is needed. If a large amplifier and/or high power bass levels are used, four 2 ohm, 25 watt resistors can be used in a series/parallel combination that will provide a 100 watt rating at 2 ohms. Caution--Depending upon how loud the system is played, the resistor could become hot and cause a painful burn.

    In the event of the diaphragm bottoming from extreme bass (such as the LFE in movie tracks), capacitors can be inserted in lieu of the Bass Attenuator jumper to act as a high-pass function. The capacitor values will depend on the desired crossover point.

  8. Fine-tuning the bass and midbass of floor-standing models with the DWM

    Due to standing waves, dips and peaks in the bass and midbass are a fact of life. Each room has its sonic signature depending upon the size, shape and construction. Some sound rooms are "hostile" to dipoles and it is difficult to generate bass or midbass. One solution is electronic equalization to deal with room aberrations. Many of the newer receivers and processors incorporate a microphone and automatic EQ that will correct frequency imbalances. However, this approach has drawbacks and is not well accepted by most audiophiles. There is another and better solution.

    Multiple subwoofers are commonly used to smooth room bass response. Although an expensive solution, this technique has been proven to be superior to EQ of a single subwoofer. Using the same fundamentals of acoustics, the DWM can fine-tune the bass and midbass of our floor-standing models.

    The DWM can be placed along a side wall or any position of convenience. But, the DWM should be equi-distance from the listener to the floor-standing models for proper phase. Each position of the woofer in the room will give a different frequency response characteristic. This response characteristic becomes one of your means of contouring the overall response of your system. Placing the DWM against a side wall or cabinet will increase the coupling and result in both lower bass response and different midbass response. The same effect can be achieved by placing the DWM next to the floor-standing model for mutual bass coupling.

    Amplifier connection-- If your amplifier, for your floor-standing model, doubles in power from 8 ohms to 4 ohmns (or nearly doubles), it is a high-current design. Most amplifiers of this design can be safely connected in parallel with the DWM--especially if a resistor is used on the DWM for bass attenuation. If the amplifier used on the floor-standing models is not a high-current design, a separate amplifier can be used to drive the DWM.

    If you have a room that is deficient in bass/midbass, or has a midbass hole in the response, you may find that the full output of the DWM is desired. However, the addition of bass and midbass is analogous to adding seasoning to food. Just a little too much seasoning can ruin the meal. If would be a typical scenario if you find it necessary to attenuate the output of the DWM after extended listening.

    Since a power resistor will mostly be needed to attenuate the DWM output, large gauge speaker wire for the DWM is not needed or recommended. Save your money, because there is no sonic advantage to large gauge speaker wire in this application.

    Positioning and phase-- To start, the DWM should be equi-distance with your left/right Maggies. For additive bass with the 1.7s or 3.7s, move the DWM 10 inches closer from the equi-distance position toward your listening position.

  9. Service and Shipping

    In the unlikely event you should need service for your DWM Woofer, we recommend you return it through your dealer. He is experienced in providing service and can assist you if the speaker must be returned to the factory. If you determine you need to return it directly to Magnepan, ship the speaker freight prepaid to:

    Magnepan, Incorporated

    1645 Ninth St.

    White Bear Lake, MN 55110

    1-800-474-1646

    Include a note describing the nature of the problem. Please include your name, address, and a daytime telephone number.

  10. Specifications

    System Description: Planar-magnetic dipole woofer.
    Frequency Response: 40-200 Hz*
    Recommended Power: See F.A.Q. on web site www.magnepan.com
    Sensitivity: 86 dB @2.83V/1 Meter/50 Hz
    Impedance: 4 Ohms
    Dimensions: 19.25Hx22.5Wx1.25D (inches)
    Warranty: Limited 3-year to original owner
    Weight: 19 lbs.
    *Bass response will vary depending upon placement near walls, cabinet or furniture.
    Revision-- 4-4-11