DCM TF-1000 Floor standing speakers
We reviewed DCM's TF-250 loudspeaker, the smallest and least expensive in the company's Time Frame series. Although the TF-1000 stands just one rung down from the top of that line, it nonetheless bears a strong family resemblance to the TF-250. The most obvious difference is size, with the TF-1000 being about 50 percent larger overall. The shape and styling of the speaker, however, are the same. A dark-brown cloth grille wraps entirely around the wide, shallow cabinet, which is capped top and bottom with wood endpieces finished in dark oak. Two short wooden feet swing out from beneath the cabinet to prevent it from tipping over. Amplifier connections are made to color-coded spring clips recessed into the back panel.
TF-1000s are sold in mirror-image pairs, with the drivers aligned almost vertically near the inner edge of the front baffle. On top is a 4-inch midrange cone, followed by a 3/4-inch soft-dome tweeter and an 8-inch woofer. The tweeter is fitted with an acoustic lens to reduce diffraction, and the woofer is loaded by a tapered transmission line that terminates in a port on the front of the enclosure. All three drivers are on the upper half of the baffle; the port is a little more than halfway down, near the outside edge. As with other DCM loudspeakers, the TF-1000 is designed to minimize errors in phase as well as in amplitude response.
DCM makes no specific recommendation as to how far the TF-1000 should be placed from walls, so Diversified Science Laboratories measured the loudspeaker's response both against the back wall and several feet out into the room. The against-the-wall curves showed better bass response and about equal smoothness, so that position was used for all other measurements and for our published response graph. As you can see, the on-axis response is within about ±4 dB from 40 Hz to 16 kHz, and the off-axis spread is very similar-about + 3, - 5 dB over the same range. Particularly noteworthy is the excellent tracking of the two curves all the way up to the top octave, where most other speakers show significant divergence as the tweeter becomes more directive. The main feature of both curves is a trough centered at about 250 Hz. This undoubtedly is the result of interference from a reflection off the floor rather than a characteristic of the TF-1000's inherent response.
Sensitivity is fairly high, as is the impedance over much of the audio band. The latter ranges from a low of 3.3 ohms at 200 Hz to a high of 17.1 ohms at 1.5 kHz. Impedance from about 4 kHz up is in the vicinity of 5 ohms. At the bottom, below 70 Hz, the curve shows signs of the classic double hump that is characteristic of ported systems. The peaks are relatively subdued, however, probably because of the damping afforded by the transmission line.
In our 300-Hz pulse power-handling test, the TF-1000 accepted the equivalent of 26.8 dBW (481 watts) peak into 8 ohms, generating a calculated peak sound pressure level of approximately 118 dB. Distortion is impressively low, even in the deep bass and at high drive levels. At 85 and 90 dB SPL (our two lowest test levels), total harmonic distortion seldom topped 1 percent at any frequency and averaged well under that. Distortion naturally increases at higher levels, though surprisingly little in this case. Indeed, it never exceeded 2 percent at any frequency from 30 Hz to 10 kHz until the lab pushed the speaker to 100 dB SPL-our highest test level. This exceptional distortion performance confirms that the TF-1000 is capable of preserving the full dynamic range of today's finest digital recordings.
We confirmed this, as well as the smoothness suggested by the response curves, in our listening tests. When placed in just about any reasonable spot, the TF-1000 sounds good from just about any normal listening position. It provides truly full-range response, reaching from the bottom to the top of the musical spectrum. Tonal balance is even and uncolored, and the stereo image rendered from appropriately recorded works combines precision with a good sense of openness and depth.
DCM says it is particularly proud of the value delivered by its Time Frame line-justifiably so, we would say. The TF-1000 is not cheap, but for a speaker of its size and performance, it is something of a bargain.
