DCM TFE 200 Loudspeakers.

Manufacturer: DCM Loudspeakers, 1Mitek Plaza.

Winslow, IL 61089

Price: $1,000/pair

Source: Manufacturer loan

Reviewer: David A. Rich

Specifications:

Dimensions: 45-11/16"H x 8"W x 20-7/8"D

Weight: 60 lb

Tweeter: 30-mm cloth dome

Midrange: 6-1/2" Kevlar cone

Woofer: Two 6-1/2" glass fiber cones

In the mid-1970s, audiophiles sought superior sonic performance from the respected loudspeaker manufacturers of the era: AR, KLH, Dynaco, Advent, JBL, Klipsch, Bozak, Electro-Voice, Altec-Lansing, JBL, and Janszen, to name a few American firms. Although some models emerged that had characteristics audiophiles prefer, they tended to be both quirky in design and expensive. Then, the DCM Time Window came on the scene, and suddenly audiophiles with $660 to spend on a pair could achieve their objectives.

For whatever reason, DCM drifted away from the high-end market and became a major supplier to Circuit City. But the relentless drive to lower costs to remain competitive in the mid-fi distribution chain harmed the DCM brand image and diminished the quality and performance of its product line. Eventually, DCM was purchased by Mitek, which now hopes to reclaim the reputation for engineering leadership and value that DCM once held by introducing the TimeFrame Evolution line.

The TFE 200 under review here is top-of-the-line TFE model. The development project that brought the TFE 200 to market was led by Dan Roemer, one of Professor R.A. Greiner's last graduate students at the University of Wisconsin.

The speaker is a three-way unit with bass delivered by a pair of 6.5" glass-fiber-coned woofers in a vented enclosure. As you can see from the cabinet dimensions above, this is a big speaker. Removing the drivers from the box reveals stamped metal frames, but the magnet size is healthy and the rest of the speaker looks to be of high quality. DCM specifies the sensitivity of 88dB (2.83 V/1m). I think that is a dB optimistic but, as I have said in the past, lower sensitivity is good, because we can trade sensitivity for bass extension. To my mind this is not an issue in 2005, when 100-watt amps (8 ohms) can be made for under $10 in the Far East. Even at these low prices, these amps can drive sub-4-ohm loads with no problems thanks to advanced protection circuits and modern output devices. In the case of the TFE 200, what the lower efficiency provides, in partnership with the largest enclosure of any speaker I have tested, is very deep, low-distortion bass. In room measurements using the ETF psychoacoustic mode, bass output suggests full bass down to 30Hz.

Unfortunately, I do not have the equipment to measure impedance curve and phase angle; however, I doubt that the impedance characteristics would present any problems to any of the AV receivers I have examined save for units that use some type of Class D amplifier.

The midrange is a 6.5" unit with a Kevlar[R] cone in its own sealed enclosure. The tweeter is a soft dome unit that sits below the midrange driver. The size of the cabinet and the quality of the drivers make the speakers appear to be a big bargain at their $1000/ pair price.

Looking at the individual response curves, it may be better to think of the 6.5-inch woofers as subwoofers. The woofers' response is bandpass in nature, reaching a maximum output at 90Hz. The 6.5" midrange lowpass starts rolling off slowly at 200Hz, reaching -4dB at 60Hz and then descending to what I have defined as the minimum operating frequency of a driver (-20dB from passband level) at 30Hz. Between 60Hz and 200Hz, the woofer fills in as the midrange rolls off. The woofer highpass rolloff is quite slow, with its operating range (-20dB) extending to 700Hz. A giant inductor in the crossover is responsible for the woofer rolloff, which starts somewhere in the 100Hz range. It is hard to identify the exact point, as the woofer is not designed to be flat.

The port becomes active on the other side of the woofers' sloping response curve; the port output reaches a peak at 30Hz. Below 30Hz, the total output declines. Essentially, this is a well designed mini-monitor sitting on what can be thought of as a subwoofer, even though the woofer system really does not reach true 25 Hz extension. But note well that all the drivers are in the same box, the crossovers are staggered in frequency; and the mechanical rolloff of the drivers plays a key role in the crossover's operation. Also, note that the midrange is a sealed system with an over-damped second-order response, not the under-damped, fourth-order response characteristic of the typical mini-monitor (by mini-monitor I mean any two way bookshelf speaker with a woofer not exceeding 6.5 inches), which is almost impossible to merge seamlessly with a subwoofer.

The high-pass crossover to the tweeter is at 2 kHz. The driver operating range (-20dB), normalized to the center of the crossover point, is strongly suggestive of a well-designed fourth-order crossover. The crossover occurs at -6dB, which is expected in an even-order, fourth-order crossover designed to sum to a flat response. The wide range of frequencies that the TFE 200 midrange operates over (100 Hz to 2 kHz) in a sealed enclosure distinguishes this speaker from the majority of 3-way floorstanding loudspeakers. The low tweeter crossover gets the 6.5" midrange out of the way before it becomes too directional (an important issue when you are designing for flat power response), but the larger driver makes it harder to achieve uniform horizontal polar response compared to speakers using a 5" cone or a dome midrange.

DCM designs for flat response over a large horizontal (90[degrees]) window and vertical (30[degrees] more than twice the normal angle limits) window. This is unique in that the company is not optimizing total power response of the speaker without concern for where the energy is coming from the speaker, but instead using very large windows around the vertical and horizontal plane. I tried to get more details on this from DCM, but they appear to be reluctant to give out all the information on their secret recipe for making excellent sounding speakers.

Figure 1 (top curve) shows the effect of the metal grill on the speaker's frequency response. Although the grill does result in additional ripples in the speaker's frequency response, it also reduces its rising high end output. Esthetically, the speaker is designed to have its grill on; the large plastic pieces that hold the grill in place look out of place with the grill absent. The bottom curve shows an average of the best 5 individual frequency response curves made over a variety of vertical angles. Because this speaker has its tweeter below the midrange, I found the direct frequency of the TFE 200 was flattest when these measurements were made 7.5 degrees above the tweeter level, so the best 5 curves ranged from -7.5 degrees to 22.5 degrees.

[FIGURE 1 OMITTED]

DCM supplied a curve (Figure 2) of an average of curves over a [+ or -] 30[degrees] angle (more than twice the normal angle limits). What is commendable here is how flat the curve looks over such a wide angle. Many speakers fall to pieces over the normal [+ or -] 15[degrees] range. Note that the energy loss in the crossover region is very small, indicating again the company's emphasis on flat power response. The unevenness in the tweeter response in both my and the manufacturer's data is not easy to explain.

[FIGURE 2 OMITTED]

Figure 3 shows the individual vertical response plots. The upper curve represents increasing angles above the tweeter from on-axis (darkest curve) to 22.5[degrees] (lightest curve) in 7.5[degrees] steps. The lower curve represents decreasing angle below the tweeter from on-axis (darkest curve) to -22.5[degrees] (lightest curve) in 7.5[degrees] steps. Getting these individual response curves to align at many points of similarity proved difficult; changing the gain offsets of the individual curves could result in a very different-looking vertical profiles from the ones I present. Variations below 500Hz may be the result of changing floor reflection effects that result from my moving the microphone close to the floor to make measurements with large negative angles, and may not be related to the speaker's performance. I did not attempt to raise this heavy speaker above the floor to reduce these effects.

[FIGURE 3 OMITTED]

I do find it strange that the effects are more significant than other floorstanding speakers I have measured. Another possible explanation may be that the slow rolloff of the woofers (as mentioned before the woofers do not go below--20dB until 700Hz) interferes with the midrange driver.

The variations in the 1-3 kHz range are crossover-related. The large dips at -15[degrees] and -22.5[degrees] suggest listening to the speaker on the floor will compromise performance. Although most of us do not listen on the floor, these off-axis response characteristics may come back to the ear as early reflections. Above-tweeter-axis constructive interference is seen. This indicates the drivers are not operating fully in phase at the crossover point. Subjectively, the speakers' sound does not change dramatically across all possible ear heights save sitting on the floor. The TFE 200 sounds very good even when the listener is standing.

The upper curve of Figure 4 shows changes in response with increasing horizontal angle The graph shows 4 curves ranging from on-axis (darkest curve) to 45[degrees] (lightest curve) in 15[degrees] steps. The lower curve is the average of the curves above (double weight for off-axis curves). Note: I have maintained a +7.5[degrees] vertical offset to the tweeter for the horizontal dispersion curves shown in Figure 4, as this resulted in the flattest curve set. The TFE 200 is flat only off-axis, with a rising treble response on-axis. The cause of the variation in signal amplitude in the 2-4 kHz range with horizontal angle change is not clear, as this is above the crossover point to the tweeter. The average of these curves is shown in the bottom curve of Figure 4. Besides the dip at 1.5 kHz, the most notable feature is that the tweeter output is above midrange level on-axis.

[FIGURE 4 OMITTED]

The horizontal power response curve supplied by DCM looks similar to my measurements, but the tweeter/midrange levels are more closely matched, although still not fully balanced. The DCM measurement is made over a very wide set of angles ([+ or -] 90[degrees]) to emphasize the power response of the speaker in the horizontal plane. The wider set of angles used for the measurements in the average may account for the flatter overall curve. Like my curves, the DCM plots are gated, although they have better facilities, resulting in better accuracy at lower frequencies. Despite this, DCM cautions us only to look at these curves above 200Hz.

Listening tests were done with the grills on the speaker. On first hearing, the listener is immediately struck by the brightness of sound--something that would be even more dominant if the grill were left off. After a little time is taken to get used to the balance, transparency emerges as the dominant speaker characteristic. The speaker's design goal for flat power response and its absence of any dip in the 2-4 kHz region may be partly responsible for this sense of transparency. Although the speaker is forward in sound, it does not sound edgy at the top. Dynamic contrasts are well defined, adding to the liveliness of the sound. I think some of these added dynamics are the result of the speaker's fully extended bass response. Even the best mini-monitors sound really tiny when compared to the TFE 200. You can purchase a mini-monitor for twice the price of the TFE 200, but the DCM makes a very strong case for going with a full-range tower speaker if your room layout allows you to use a speaker of this size. Integrating all these characteristics, instruments sound more real, even if the tonality is a little untidy. Overall, the speaker's tonality reminds me of what one hears at trade shows from $5-figure speakers targeted at audiophiles. However, making comparisons like this should always be taken with a grain of salt. Music lovers are warned that the tonality of this speaker is not the best match for CDs of merely average quality.

The TFE 200 goes as deep as any speaker I have had in my house. The bass quality does not change at high dynamic levels in a big room. You can amaze your friends when playing drum wallops on Telarc recordings, but more significant is the quality of the massed double bass and the lower brass. You need to move the TFE 200 around and keep it away from the walls if the bass is not to become too dominant. I have found that speakers with significant bass extension below 40Hz are much harder to get balanced so the low end does not dominate. I have hopes that parametric equalization on newer AV receivers may make getting deep and flat bass possible in most rooms, but I have not tested an AV receiver with such a feature yet. I also again note these are big speakers that will work best in a larger room. In a smaller room it is going to be hard to get these big speakers away from the back wall while still being able to sit 8 feet away from them.

Image height is a little high, with the sound appearing to be a localized to the midrange, which you recall is on the top of the tweeter in this speaker. That the bright yellow midrange can be clearly seen through the grill may enhance this effect, but it is present even when closes one's eyes. Instruments or voices are not stuck in the box, but seem to float around it. The speaker's ability to float the musicians adds to a realism of the sound that I have not experienced with other speakers I have tested in my listening room. The virtual center is less well defined from the TFE 200 in comparison to speakers that employ wave guides to reduce early reflections. Again I note that the image floats around the speaker, while other speakers I have tested tend to disappear from the soundstage almost completely; but these speakers appear to place a veil over the sound in comparison to the TFE 200. The woofers are not localizable as they would be if the crossover point to the midrange were higher. All instruments emerge from the same vertical plane around the midrange, which I believe is a major plus, especially for full orchestral recordings.

At $1000/pr, this speaker has much to offer the audiophile. Even in a large room, my ears will give up before the speaker, yet the speaker is well balanced when a single instrument is playing. Bass power and extension add to the liveliness of the reproduced sound. The TFE 200 is insensitive to what you drive it with (3-watt tube amps excepted). The speaker does all I describe above even if you drive it with a $300 AV receiver. These are all good things, but this speaker may not appeal to everyone. The DCM's forwardness and reduced ability to produce a very solid phantom image may not be to your liking.

As with the original Time Window, many audiophiles may find little reason to spend more money on speakers than the TFE 200's retail price. Overall, the TFE 200 is a truly worthy successor to the Time Window.