MANUFACTURER'S SPECIFICATIONS
Nominal Impedance: 8 ohms.
Drivers: One 10-in. woofer in ported enclosure, one high frequency horn.
Crossover Frequency: 2000 Hz. Control: Tweeter Balance.
Usable Frequency Range: 35 to 17,000 Hz.
Grille: Removable sculptured foam.
Dimensions: 16 in. D x 16 in. W x 21 1/2 in. H.
Price: $200.00.
The Frazier Concerto is a two-way speaker system using a high compliance 10-in. woofer in a vented enclosure for bass and medium frequencies, and a horn tweeter for frequencies above the crossover of 2000 Hz. The top and both sides of the enclosure are attractively finished in natural wood and a removable sculptured-foam grille is available in burnt orange, brown, or black.
This system is designed to be a floor-standing reproducer, and with a height of 21 1/2 inches and a mar-resistant floor standing base, it is, as stated by Frazier, perfect end table height. The enclosure has a sufficiently sturdy top and a low enough center of gravity that lamps, ashtrays, and the like may be safely placed on the Concerto if this recommendation is taken, but the finish of the wood top can suffer if abused, as with any piece of fine furniture.
The unfinished back of the Concerto contains the tweeter control in a recessed cavity. Unfortunately, this rotary control is neither labeled nor supplied with a knob to identify position should it be desired to change the balance. Because the control is a potentiometer that can be set from zero tweeter output to a level much "hotter" than the woofer, it is hoped by this reviewer that Frazier will improve this situation in future production units. In the unit tested by AUDIO, the most accurate balance for direct sound was found to occur about midway between the extreme positions of this control.
A terminal strip is mounted on the back for electrical connection to the speaker, and the terminals are marked with small but legible polarity marks. This is a screw terminal type of mounting which will take either spade lugs or bare wire. The screw terminals are very close together and no mechanical barrier is provided between the exposed terminals. Care must therefore be taken in hookup so that an accidental short circuit does not occur due to a loose or improperly made connection. Single conductor wire, rather than stranded hookup wire, is recommended by Luis reviewer for the Frazier Concerto to minimize the possibility of an amplifier-damaging short circuit during hookup, and the chance of such an occurrence if the speaker is frequently moved for cleaning or decor purposes. Under no circumstance should hookup be made to the speaker while the amplifier is on and delivering program material. Again, this reviewer hopes Frazier will improve this situation on future models.
(Frazier tells us that the current version of this model uses banana plugs to alleviate this problem. -Ed.) No hookup instructions or recommendations (that would be helpful to a less technical user) were supplied with the model received by AUDIO. The Frazier Concerto carries a five-year warranty against defects in workmanship and materials.
Technical Measurements
Fig. 1--Impedance control. for two extreme positions of tweeter control.
Fig. 2--Magnitude and phase of the response one meter on-axis with one anechoic.
Fig. 3--Frequency response of the first 10 milliseconds of sound in a conventional listening situation three meters from the Frazier Concerto. On-axis and stereo response shifted 10 dB for clarity.
The Concerto is rated as an 8-ohm system, and this is a realistic minimum value as shown in the impedance plot of Fig. 1. The impedance plot has the two low-frequency peaks characteristic of a vented system. The lower peak occurs at 18 Hz and the upper peak at slightly above 60 Hz. Because the tweeter control is potentiometric, the plot is made for the two extreme control positions. In any other control position, the impedance will lie between these two curves.
The one-meter anechoic frequency response for a one watt excitation is shown in Fig. 2. The Concerto ranks as a moderately efficient system and satisfactory sound level can be produced from amplifiers rated 20 to 50 watt. The pressure amplitude shows a low frequency roll-off below 90 Hz. The fact that this does not occur near the 38 Hz impedance minimum of Fig. 1, as well as the nearly 12 decibel per octave roll-off, suggests that this phase-inverter vented enclosure was not designed by Frazier engineers according to the more conventional alignments of such systems.
The pressure phase spectrum of the Concerto is technically very interesting because there is an exact 180 degree phase change which occurs between 1400 Hz and 2100 Hz. The conventional logarithmic frequency plot is difficult to interpret under these circumstances, however a linear frequency plot of the phase spectrum (not included) discloses that the woofer is precisely in phase with the drive voltage. By this we mean that a positive voltage applied to the positive speaker terminal will produce an acoustic pressure increase exactly in phase with that voltage for high frequencies. The Concerto is thus phased properly for bass should it be desired to use it with other speakers, such as for quadraphonic rear channel operation. The tweeter is 180 degrees out of phase above 3 kHz and has a mean average acoustic position approximately 2.4 inches behind that of the woofer. The SPL response dip at around 1.4 kHz is due to this polarity reversal between woofer and tweeter.
This does not mean that Frazier was careless in assembly. Quite the contrary. reversing the tweeter leads to bring it into phase with the woofer actually produces a very audible broad dip in response at around 2.5 kHz.
The three-meter room response of Fig. 3 shows the effect of the room in filling up this apparent dip. Figure 2 is the anechoic response which does not contain any wall, floor, or ceiling reflections. Figure 3 is the spectrum of the first 10 milliseconds of "early" sound when the Concerto is placed on a carpeted floor. The on-axis and 30 degrees off-axis measurements are shifted 10 dB in Fig. 3 for simplicity of presentation. The low height of the woofer above the floor causes a multiplicity of SPL interference notches below 2 kHz due to the grazing sound incidence when the speaker is listened to in a conventional manner. Ceiling reflections are less severe than floor reflections because of the vertical polar response of both woofer and tweeter. The power spectrum of the early sound shown in Fig. 3 is thus much more uniform on the average than the anechoic response of Fig. 2. The Concerto should, and does, sound quite smooth in the 1 to 5 kHz range even though the anechoic response shows a dip. However, the severity of interference notches due to the shallow vertical height of the Frazier Concerto suggests that this speaker should be placed on an acoustically dead surface, such as a rug. in preference to a hard floor. The surprising feature of the three-meter test is that the phase (not shown) of the early sound uniformly changes its full 180 degrees, starting at 1.4 kHz and ending at 2.1 kHz without the slightest trace of a power spectrum dip or peak.
The harmonic distortion for the musical tones E1, A2, and A4 is shown in Fig. 4. These are measurements made on the woofer since it handles the spectrum below 2 kHz.
Intermodulation distortion for the tones E, and A, mixed 1:1 is shown in Fig. 5. The rather unusual shape of this curve is due to the spectrum modification of the modulation with increase in drive. At low power levels the dominant side bands about A, are even order harmonics of E,. With increase in drive power, the odd order sidebands become prominent while some even order sidebands remain constant and the others decrease. At the higher power levels, this particular two tone intermodulation is almost equally due to phase and amplitude modulation. The implication of both the harmonic and intermodulation characteristics is that low bass program material such as pipe organ will not be reproduced to the full satisfaction of highly critical listeners.
Crescendo handling capability is measured by noting the extent to which an inner musical voice is suppressed by the introduction of a higher power wide-band random-noise signal. One decibel of 440 Hz suppression occurred with a peak power of 450 watts, corresponding to an average noise power of 50 watts spread over a band of 20 Hz to 20 kHz. The Concerto is thus capable of handling musical peaks well above its stated continuous rating of 25 watts.
The one-meter polar energy response is shown in Fig. 6. This is quite an acceptable polar pattern and shows that good stereo separation of sound should be obtained without any tendency to bias the sound image either to the right or left. Slightly better high frequency response in a stereo configuration can be obtained by rotating the speakers toward the listening area.
The response to a band limited impulse is shown in Fig. 7. The equivalent signal applied for this test is a nearly perfect impulse which has been band limited in its frequency content to contain only components from 20 Hz to 20 kHz. The shape of this frequency spectrum is modified by what is called hamming weighting to more accurately portray the time response of Fig. 7. The data plot of Fig. 7 has been automatically clipped to a baseline 40 dB below the peak energy value. The double humps centered at 3.25 milliseconds are due to the woofer. The main peak at 3.43 milliseconds is due to the horn tweeter as are the subsequent peaks at 3.65 and 3.9 milliseconds. The equivalent positions of major components in the Frazier Concerto are shown in Fig. 7 for comparison.
Fig 4--Harmonic distortion for musical tone of E1, A2, and A1.
Fig. 5--Intermodulation distortion of A4 (440 Hz) by E1 (41 Hz) mixed 1:1.
Fig. 6--Polar energy response.
Fig. 7--Energy-time response for a perfect impulse, hamming weighted and
band limited 20 to 20,000 Hz, measured one meter on axis.
Listening Test
The Concerto does a creditable job of realistically reproducing program material which possesses strong midrange components. While the extreme high frequencies are down in level, the drop-off is smooth and free from annoying presence peaks. It is thus possible to employ a moderate high frequency boost without incurring a "spitty" top end.
In this reviewer's opinion, the Concerto's deficiency of very low bass response is its least advantageous acoustic characteristic. Three positions of the speaker were auditioned: floor standing away from a wall, against a flat wall, and in a corner. Only the corner position provided a reasonable bass response without the excessive use of a tone control equalization. In other room positions the deficiency in bass was quite noticeable. Bass boost by means of a conventional tone control is not recommended for moderately loud reproduction of material which has good low frequency content because good, deep bass begins to sound "blasty" as the level is raised.
Subsonic frequencies, such as due to reproduction of a badly warped record, can cause audible program modulation at high sound levels in the Concerto. For this reason, this […]
Angular dispersion is quite smooth within thirty degrees of the on-axis position. Mounting the Concerto in a corner should provide a smooth stereo sound image since most listening positions will be within this angular spread. For wall or floor mounting positions it is helpful to rotate the speakers slightly toward the listening area.
Acoustic balancing of the unmarked tweeter controls can be quite a chore for stereo listening. This reviewer recommends that after placing the Concertos where you want them to be, rotate each tweeter control shaft to a position halfway between its extreme left and right position. Using an FM tuner as source, tune it off station so as to get the characteristic "rushing" sound. Then make any fine adjustments necessary to the tweeter controls to make the noise sound as close as you can to the sound of a shower spray which seems to come from a position halfway between the speakers. Because of the high frequency de-emphasis in the FM tuner, it is advisable to apply some tone control treble boost to aid the sonic illusion of a shower spray.
The Frazier Concerto can be recommended to those whose preferences run to "easy listening" music, but in this reviewer's opinion, this speaker would not fare so well with those who demand low organ, bass, cello or piano fundamentals.
-Richard C. Heyser
(Audio magazine, Mar. 1974)
Also see:
Frankmann Integrated Stereo Speaker System (Jul. 1974)
Fairfax FX-300 Speaker System (Nov. 1972)
Fisher ST-425 Speaker System (Equip. Profile, Jan. 1975)
Fried Products Model Q Loudspeaker System (Jun. 1980)
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