Hello and welcome to my DCM fan site. On this webpage you will find information on the revered DCM Time Windows speaker system and it's use. I will also include photos and information on how to service the Time Windows system, as well as provide a gathering space to hear how other owners have either tweaked or setup their system as well.
My history with DCM loudspeakers started back in 1981 when I bought my first DCM speaker, the QED. I was struck by the smooth treble response and clean bass, characteristics that I always look for when shopping for accuracy in loudspeakers. I used these speakers until 1998, when I upgraded to a pair of Time Windows 3...
The Time Window, originally designed in 1974 by DCM founder Steve Eberbach, has been designed in such a way that it produces a 270 degree horizontal dispersion pattern. The front of the speaker is shaped like a triangle, which divides into two "L" and "R" sided baffles. These two baffles have speaker drivers mounted in them which when combined, sum into a coherent 270 degree radiation pattern.
The speakers are designed as "Left and Right Channel" mirrored pairs. For example, the "Right" channel speaker is designed in this manner: On the left baffle, the speaker drivers produce a direct sound field. On the right baffle, the mounted drivers are designed to reflect sound off a right side wall. The Time Window also has adjustable controls which allow the user to adjust the mid and treble volume reproduced from the right reflection baffle. Thus, this design approach allows one to adjust the spread of the soundstage in terms of both mid and high frequencies.
When I listen to classical music for example, I tend to adjust the controls so that I have the widest possible soundstage which would resemble what one would hear at a symphony concert. For Jazz, Rock, or other musical styles I set these to produce a more focused sound with the soundstaging reduced. There are no hard and fast rules, and it is quite fun to experiment with different settings.
The rear of the cabinet is also unique as it is curved. This produces cleaner bass as the backwave bass energy inside the cabinet does not reflect and bounce off the woofer cone as severely as it does on box shape designs. The woofers in the DCM's are also mounted high in the cabinet. This also produces cleaner bass by reducing room and floor interactions.
Speaker Placement: My DCM's are 11" above the floor on speaker stands, and about 2 ft away from the back wall. If I place these too close to the rear wall I find the bass to be too strong.
Shown below is a scan from the Time Window 3 system owner's manual showing the specs of this speaker.
The tweeter of the TW3 is mounted coaxially in front of the mid-bass driver and can also be boosted by 2db by means of a potentiometer mounted on the rear of the cabinet. In front of the tweeter and mid bass driver is an acoustic lense.
The crossover board in the DCM TW3 is factory calibrated to adjust for variables in the various components. On the rear of the cabinet are additional potentiometers which tune the crossover and are factory set. Outlined below, these controls are not user adjustable and should not be tampered with under normal use.
I have modified My DCM's beyond factory specs. I am presently in the process of adding dampening materials to the inside walls of the cabinet. Modeling clay applied to polystyrene sheets can be attached to inside sections of the cabinet as suggested by Steve Eberbach. As shown below, This is a view of the DCM TW3 looking inside the cabinet directly downward from the top. The rear, curved wall directly behind the speaker drivers is shown with the white and black clay attached to the sheets and then to the cabinet. The modeling clay never dries-it is always moist. This provides excellent dampening properties. The speaker magnets are also visible and covered with clay (photo bottom). Installing the clay is a fairly involved process, and I'd suggest this only for those who are experienced. The wiring is fairly complex, and great care must be taken not to dislodge it. Also shown is some thick, solid core copper wire I installed as an experiment. I've also soldered all connections in place of terminal connections, as well as provide a bypass around the speaker input banana plugs.
When servicing the Time Windows, great care is required because the design is not a conventional one. Access inside the cabinet is gained by removing a 7/16" nut that secures the wooden bottom half into place. This nut is attached to a steel rod that runs the entire vertical length of the cabinet, which terminates to the top wooden half. The crossover is secured to the bottom, wooden half, and the steel rod runs through the center of the board. When the nut is tightened, it is compressing both the top and bottom half into place.
When the nut is removed, the bottom half (along with the crossover board), lifts off the steel rod that runs through the cabinet. When re-installing, the steel rod must be guided through the center hole in the crossover board and wooden half with either a straw or screwdriver or some similiar object. It's important to ensure that during reinstallation that inductor coils do not bump against the edge of the cabinet, as this can cause a short circuit. If you decide to service this system yourself, be alert, cautious, and take your time. Crossover components may not be readily available.
Here's a link to a forum discussion on DCM related topics, including an interesting new DCM center channel speaker design:
DCM Speaker DiscussionThis link will take you a page with information on other vintage DCM gear:
More DCM Vintage Audio GearI can be emailed at bobaudio3@yahoo.com
This link will search Amazon for Audio gear. If you'd like to support this website, merely clicking on this link and purchasing anything from Amazon helps to support my efforts. Thanks!
This link will take you to a service that performs modifications to PCB's (Printed Circuit Boards).
Links To Other Interesting Sites
About Audio Restoration
DVD Transfer Services
The Unofficial Joe Meek Webpage
The Edison Phonograph
Amazon Music Search
PCB (Printed Circuit Board) Rework and Modification Service
Online Garage Sale Webpage
Here's a link to a nifty Ebay store that sells Postcards, Jewelry, Books, Magazines, and French Revolution items!
KyerSolsay Ebay Store