Coincident Triumph Signature Speaker

By: Edward M. Long

   The Triumph Signature is Coincident Speaker Technology's only bookshelf speaker.  The company also makes six floor-standing speakers (the Conquest series) and a Mini Subwoofer.
   A two-way system, the Triumph Signature has a 1-inch silk-dome tweeter and a 61/2-inch woofer, both with large magnets (the woofer's is about 31/2 inches in diameter and nearly 3/4 inch thick). The woofer has a polypropylene cone, a rubber surround, and a cast frame.  Its effective cone diameter is about 43/4 inches, typical for a driver this size, and its 11/2-inch voice coil gives it good power handling. Both drivers are flush-mounted, the tweeter with five self-tapping cap screws and the woofer with four cap bolts and Tee nuts.  Center to center, the distance between the drivers is 55/8 inches.
   The vented enclosure is tuned to about 43Hz, but the Triumph Signature's bass response actually starts rolling off at about 60Hz.  The enclosure's interior volume, which seems to be the optimum size for a 61/2-inch woofer, is 931 cubic inches (15.25 liters) augmented by a small amount of polyester damping fiber that makes it act like a slightly larger box.  The front baffle's edges are bevelled at a 45° angle.  The cabinet's medium-density fiberboard (MDF) walls, which are 1 inch thick, are veneered inside as well as out, an expensive-and welcome-touch that prevents uneven moisture absorption and possible warping.  The outside veneer, which covers all six sides of the cabinet, was cherry on my samples, stained a light red.  The speakers are available with or without grilles (none came with the pair I received for testing). The grilles attach with Velcro tapes; they are free if ordered with the speakers and cost $35 if ordered separately.
   On the rear are gold-plated terminals, with red and black bands to indicate polarity, mounted on a black acrylic plate.  The holes in these terminals are not large enough to accept cables thicker than 18 gauge.  The terminals will accept single-banana plugs but are too far apart for double-bananas.
   The crossover's low-pass network has an air-core inductor in series with the woofer and a shunt capacitor across its terminals; nonetheless, it could be classified as a first-order network because a resistor in series with the shunt capacitor negates much of the capacitor's influence.  The high-pass network feeds the tweeter through a capacitor, a resistor dividing network to reduce the tweeter's output, and finally a series resistor bypassed by a capacitor to boost extremely high frequencies.  The woofer and tweeter are connected so as to produce an outward diaphragm motion for an initial positive DC input.

   The Coincident Technology Triumph Signature's rated sensitivity is 90 dB for 1 watt input at 1 meter, but based on its on-axis frequency response (Fig. 1), its sensitivity except in the low bass and in the treble-is actually between 84 and 88 dB.  This is still very good, however.  The woofer's and tweeter's outputs overlap substantially in the crossover region.  That's to be expected of a speaker whose low- and high-pass filters are essentially first-order, and it makes the exact frequency of the acoustical crossover very difficult to determine.  Near 2 kHz, in the crossover region, the Triumph Signature's overall output is lower than the output of either of its drivers alone; this indicates that some cancellation is occurring.
   The reason for this cancellation can be gleaned from Fig. 2, the Triumph Signature's phase response. The tweeter and woofer outputs are 180° out of phase at 1,950 Hz, which is in the crossover range.  This corresponds to a difference of 256 microseconds, a half wavelength; it is also equivalent to a displacement between the drivers of almost 31/2 inches.  Although the woofer and tweeter are connected to produce a positive acoustical output for a positive electrical input, Fig. 3 reveals that the first energy from the tweeter arrives at the test microphone 110 microseconds before the first energy from the woofer.
   You might wonder why I said that there was a 256-microsecond difference between the drivers' outputs at 1,950 Hz when the energy/time curves (ETCs) in Fig. 3 indicate only 110 microseconds.  There is no inconsistency: The 256-microsecond result derives from the phase angle at a specific frequency, whereas the ETC reveals the time difference between all the frequencies produced by the tweeter and all those produced by the woofer.  The 110 microseconds represents the time difference between the peak of the tweeter's ETC and the peak of the woofer's ETC.
   The Triumph Signature's impedance is rated at 8 ohms nominal and 6 ohms minimum, but at 20 kHz it drops to about 5.4 ohms (Fig. 4). The peaks at 25 and 77 Hz are about 15 and 18 ohms, respectively; above 200 Hz, the impedance curve is very uniform.  The Signature's impedance characteristics should make it a relatively easy load for any modern amplifier whose internal impedance is low, and this speaker should sound pretty much the same with most such amplifiers.
   Even at the relatively high level of 100 dB SPL, the Triumph Signature's second- and third-harmonic distortion is very low (Fig. 5).  The highest relevant distortion products are only 2% second harmonic and 1.8% third harmonic at 60 Hz.  This is very good performance, as distortion in the bass is generally less annoying than midrange distortion.  (You can safely ignore the distortion peaks at 20 Hz. Measurement resolution is poor down there, and the speaker's rolloff and the scarcity of program material near that frequency means you'll rarely hear distortion anyway.)  Above 60 Hz, distortion is mostly less than 1.8%.  The Signature's excellent performance in this regard means that instrumental timbres will not be adversely affected by harmonic distortion.
   Figure 6 shows the Triumph Signature's on- and off-axis frequency responses.  Off-axis response is most uniform when the speaker's cabinet is upright (Fig. 6A). The curves are close together, even at 45° off axis, up to about 5 kHz; from 60 Hz to 18 kHz, the response varies only ±5 dB up to 30° off axis.  When the Triumph Signature must be used on its side, which I don't recommend, its sound will vary with the angle of your listening position.  The best compromise may be to place these Coincident speakers so that their tweeters are to the inside and their woofers to the outside (Fig. 6B), but you should also try it the other way.  (Fig. 6C).  Because these speakers weigh just 26 pounds a piece, this experiment should not be too difficult.
   The 300-Hz and 1-kHz square waves in Fig. 7 further attest that the Coincident speaker's treble energy arrives ahead of its bass energy.  (I have found that this tends to soften transient attacks somewhat; transient sounds seem sharper when the fundamental and harmonics arrive together.)  At 3 kHz, there is still energy coming from the woofer but even more coming from the tweeter, confirming what you see in Fig. 1. Although not perfect, the Signature's square-wave reproduction is reasonable.
   In the 20-kHz cosine pulse test (Fig. 8), the base of the acoustical output's peak is just slightly wider than that of the electrical input pulse-another sign of excellent high-frequency response.  The output curve's undershoot indicates that the speaker is rolling off in the bass yet is well damped.  (For the output pulse to be identical to the input pulse, a speaker would have to have uniform response down to DC.)  The lack of high-frequency ringing tells us that the tweeter is well damped.
   As usual for vented speakers, I measured the output of the port and the woofer separately.  The port's maximum output was constant, within 1 dB, from 40 to 60 Hz.  The woofer's output began rolling off at 100 Hz; there was a dip at 43 Hz, the system's tuning frequency.  The two Triumph Signatures' responses matched within 1 dB across the entire audio spectrum, which should help keep images very stable.  Tests of cabinet vibration turned up nothing that might contaminate the sound, thanks to the solid, 1-inch MDF enclosure walls.

Use and Listening Tests
   From the start, I was impressed by the Coincident Triumph Signature's relatively high output and wide-range sound.  Bass reproduction was very impressive, considering that it came from a single 61/2 inch driver.  The treble was very impressive, too. The midrange was clear but a little subdued, making some recordings with hyped instruments and vocals much more listenable.
   I use a listening panel to evaluate the sound quality of components that I review, because the panelists often hear things from a different perspective than I do.  The panel members write down their comments, which I review with them after the listening session.  I've described my reference speaker system in previous reports, so I will just say that it is a compact speaker whose bass response extends down to 30 Hz and whose midrange and treble response is time-coherent.
   For the listening sessions, I placed the Triumph Signatures next to and at the same height as the reference speakers and adjusted the references' output level to match the Signatures'.  The acoustic environment was relatively dead, and all the speakers were about 4 to 5 feet away from the listening position; I have found that this enables people to focus on the sound quality of small loudspeakers without the distracting effects of room reflections and standing waves.  Each panel member listened alone to the same four musical selections through both sets of speakers.
   For vocal material, I selected a fabulous, as yet unreleased, CD titled I'll Never Forget You.  It features Debra Holly, who sounds a little like June Christy, singing with a band that reminds me of Stan Kenton's.  I found the vocal to be clear and articulate on both the reference and the Coincident speakers. When listening to “Oh, What a Beautiful Mornin’,” the panel's comments about the Triumph Signatures were: “vocal very Clear,” “vocal good but a little recessed,” “brass overtones less bright,” “drums tight and punchy,” “bass solid but not as deep,” and “clarinets and saxes are more mellow.”
   For the song “Windswept,” performed by the Lynne Arriale Trio on With Words Unspoken (dmp CD-518, an excellent disc engineered by Tom Jung), comments were: “piano less forward,” “piano less bright,” “drums very tight,” “drums very good,” “snare drums have less snap,” “cymbals excellent,” and “cymbals very smooth and clear.”
   Comments for “A Celtic Medley,” by Bela Fleck and The Flecktones on Three Flew Over the Cuckoo's Nest (Warner Bros. 9453282), were: “banjo more mellow,” “banjo slightly recessed,” “banjo less forward and bright,” “banjo sounds slightly veiled,” “sax very good,” “sax less irritating,” “percussion has less snap,” “percussion sounds are very extended,” “bass is more mellow,” “bass has less overtones,” and "bass not as deep."  (I made a spectral analysis of this recording, which showed that it has content down to 36 Hz and that, from about 150 Hz down, the bass is boosted 12 dB above the midrange level! This made it useful in differentiating my reference speakers' extended bass from the more limited bass range of the Triumph Signatures.)
 The orchestral selections “Dance of the Firebird” and “Infernal Dance” from Stravinsky's Firebird Suite, with Erich Leinsdorf conducting the Los Angeles Philharmonic (Sheffield Lab 10052-2-G), elicited these comments: “woodwinds brighter,” “upper bass stronger,” “bass slightly less deep,” “celesta subdued,” “harp more mellow,” “harp less bright,” “excellent sense of depth,” “good instrument placement,” “brass less bright,” “smoother brass sound,” and “brass further back.”
   The Triumph Signatures have good off-axis treble response.  Therefore, they will sound brighter than they did in my setup if they're in a larger room whose acoustics are more live.
   I enjoyed listening to Coincident's Triumph Signatures with a wide variety of program material over an extended period.  If you like a less aggressive, less in-your-face sound, you should audition them-even on recordings you think are a little too forward and bright. I think that you will find these
speakers to be excellent.