Measurements
Fig-1: Vivid Giya G3, electrical
impedance (solid) and phase (dashed) (2 ohms/vertical div.).
I used DRA Labs' MLSSA system and a calibrated DPA 4006
microphone to measure the Vivid Giya G3's frequency response in the farfield,
and an Earthworks QTC-40 for the nearfield and spatially averaged room
responses. The G3 is specified as having a voltage sensitivity of 87dB/2.83V/m;
my estimate was slightly lower than this, at 86dB(B). How the Giya G3's impedance
magnitude and electrical phase angle vary with frequency is shown in fig.1. The
impedance drops below 6 ohms only in the bass, otherwise remaining above 4
ohms, as specified. There is a current- hungry combination of -40° phase angle
and 5.2 ohms at 25Hz; though music rarely has high energy in this region, and
the speaker's impedance in the midrange and treble is very high, a good, 4 ohm-rated
amplifier should be optimal for driving the G3. The G3's high-frequency
impedance is higher than that of the Giya G1, which uses the same drive-units,
perhaps because the drivers are resistively padded down to match the lower
sensitivity of the G3's woofers.
Fig.2: Vivid Giya G3, acoustic
crossover on tweeter axis at 50", corrected for microphone response, with
nearfield responses of: midrange unit (blue), woofers (green), ports (red),
respectively plotted below 350Hz, 2.5kHz, 380Hz.
Though there are no discontinuities in the impedance traces
(other than one at 37kHz, probably due to the first breakup mode of the
tweeter's aluminum dome), there is some unevenness. However, when I investigated
the enclosure's vibrational behavior with a plastic-tape accelerometer, I could
find no resonant modes. Listening to the various enclosure surfaces with a
stethoscope confirmed that the enclosure was, in general, very dead, if
slightly less so between 300 and 400Hz in a small region toward the speaker's
spine, just below where the coiled and tapered tube reenters the body.
Fig.3: Vivid Giya G3, anechoic
response on tweeter axis at 50", averaged across 30° horizontal window and
corrected for microphone response, with complex sum of nearfield responses
plotted below 300Hz.
Fig.2 shows the individual responses of the HF/MF drivers
(blue trace), the woofers (green), and the ports (red), the nearfield levels
scaled in the ratio of the square roots of the radiating areas. The
upper-frequency farfield response on the tweeter axis is superbly flat, with
small peaks balanced by small dips and a slight rolloff above 20kHz. The lower-midrange
unit's output rolls off steeply below the specified crossover point of 220Hz. A
couple of midrange peaks are evident in the woofers' upper-frequency output,
but the crossover suppresses these by 20dB or more. The minimum-motion notch in
the woofers' low-frequency output lies at 29Hz, as suggested by the impedance-
magnitude trace in fig.1, but is less well defined than usual for a reflex
design. The output of the ports, however, shows a classic bandpass response
that peaks at the same 29Hz and, commendably, contains no midrange peaks.
Fig-4: Vivid Giya G3, lateral
response family at 50”, normalized to response on tweeter axis, from back to
front: differences in response 90-5° off axis, reference response, differences
in response 5-90° off axis.
The G3's farfield response, averaged across a 30° horizontal
window centered on the tweeter axis, is shown to the right-hand side of fig.3,
spliced at 300Hz to the complex sum of the nearfield responses from fig.2, and
taking into account both acoustical phase and the drivers' various distances
from a nominal farfield microphone position. Again, the upper-frequency output
is impressively even, though overall, the treble appears to be balanced between
1 and 2dB lower than the average level in the midrange. This could be because
there appears to be a slight excess of energy in the two lower crossover
regions. The traces in fig.2 do suggest that there is a little too much overlap
between the woofers at the top of their passband and the lower-midrange unit at
the bottom of its passband. I plotted these traces at the theoretically correct
levels, but they might also have been affected by the assumptions one makes
when measuring a speaker in the nearfield. The small, narrow peak just below
10kHz in figs.2 and 3 is also present in my measured responses of Vivid's
Oval B1 and Giya G1; it must be a characteristic of Vivid's T26 tweeter and its
acoustic environment. However, I heard nothing wrong in this region. It is also
worth noting that the responses of the two G3 speakers matched to within 0.5dB
above 1kHz, and within even less than that above 10kHz. The G3's low
frequencies appear to extend at full level down to the port tuning frequency,
with then a steep rolloff.
Fig.5: Vivid Giya G3, vertical
response family at 50", normalized to response on listening axis, from
back to front: differences in response 15-5° above axis, reference response,
differences in response 5-10° below axis.
With its narrow, tapering front baffle and its use of three
closely spaced drive-units to cover the range from 220Hz up, it comes as no
surprise that the Giya G3's horizontal dispersion is generally wide, uniform,
and even (fig.4). However, like the Giya G1, the G3's dispersion shelves down a
little to the speaker's sides above the cursor position at 7kHz, which will
make its tonal balance rather mellow in a large room. In the vertical plane
(fig.5), the G3 appears to be relatively uncritical of exact listening axis,
which is somewhat at odds with my listening experience. But at 15° above the
tweeter axis (top trace), a suckout is evident at the upper crossover frequency
of 3.7kHz.
Fig.6: Vivid Giya G3, spatially
averaged, 1/6-octave response in JA’s listening room (red); and of Wilson
Alexia (blue).
The red trace in fig.6 shows the spatially averaged response
of the Giya G3s in my listening room. (The trace was generated by averaging 20
1/6-octave-smoothed spectra, taken for the left and right speakers individually
using SMUG- Software's FuzzMeasure 3.0 program and a 96kHz sample rate, in a
vertical rectangular grid 36" wide by 18" high and centered on the
positions of my ears.) For reference, the blue trace in this graph is the
spatially averaged response of the Wilson Alexia speakers that I reviewed in
December 2013. The Wilsons show a little more low-treble energy, but the
behavior of the two speakers in-room above 1kHz is otherwise surprisingly
similar. The Vivids have a more prominent midrange, and while the two speakers'
bass regions are both evenly balanced, the coincidence of the G3's port tuning
frequency with the frequency of the diagonal resonant mode in my room results
in a huge boost below 40Hz, with a steep rolloff below 25Hz. No wonder I found
the Vivid's low bass overripe.
Fig.7: Vivid Giya G3, step response
on tweeter axis at 50" (5ms time window, 30kHz bandwidth).
Turning to the time domain, the Giya G3's step response on
the tweeter axis is shown in fig.7. This graph indicates that all five
drive-units are connected with positive acoustic polarity and that the
tweeter's output arrives first at the microphone, followed by the
upper-midrange unit's, then the lower- midrange unit's, and then the woofers'.
Most important, the decay of each unit's step blends smoothly with the start of
the next step lower in frequency, which correlates with the excellent
frequency-domain blending of their outputs shown earlier. The cumulative
spectral-decay plot (fig.8) has a clean initial decay in the treble, but with
some low-level delayed energy.
Overall, Vivid's Giya G3 demon-strates impressively good
measured performance.
Fig-8: Vivid Giya G3, cumulative
spectral-decay plot on tweeter axis at 50" (0.15ms risetime).
|
Specifications
·
Description: Four-way, five- driver, floorstanding loud-speaker
with vented enclosure. Drive-units: 1" (25mm) aluminum-dome tweeter,
2" (50mm) aluminum-dome upper-midrange driver, 4.9" (125mm)
aluminum-cone lower-midrange unit, two 5.5" (135mm) aluminum-cone
woofers. Crossover frequencies: 220Hz, 880Hz, 3.5kHz. Frequency response:
36Hz- 33kHz, ±2dB on reference axis. Frequency range (-6dB): 33Hz-36kHz.
Sensitivity: 87dB/2.83V/m. Impedance: 6 ohms nominal, 4 ohms minimum.
Harmonic distortion: <0.5% second and third harmonic over frequency range.
Power handling: 800W program.
·
Dimensions: 45.7" (1161mm), H by 13.4" (341mm) W by
22.75" (578mm) D. Weight: 90.2 lbs (41kg).
·
Finish: High-gloss automotive paint.
·
Price $39,990/pair.
·
Manufacturer: Vivid Audio Ltd.
Associated equipment
·
Analog Sources: Linn Sondek LP12 turntable with Lingo power
supply, Linn Ekos tonearm, Linn Arkiv B cartridge.
·
Digital Sources: Marantz NA-11S1 media server; Astell&Kern
AK100 media player; Ayre Acoustics C-5xeMP universal player; Apple 2.7GHz ¡7
Mac mini running OSIO.7, iTunes 10, Pure Music 1.89; dCS Vivaldi SACD/CD
player-D/A system; Auralic Vega, NAD M51, D/A converters; Ayre Acoustics QA-9
USB A/D converter.
·
Preamplification: Channel D Seta L phono preamplifier; Pass
Labs XP-30 line preamplifier.
·
Power Amplifiers: MBL Corona C15, Pass Labs XA60.5 (both monoblocks).
·
Loudspeakers: Wilson Audio Specialties Alexia, Joseph Audio
Perspective.
·
Cables : Digital: Kubala-Sosna Elation! AES/EBU,
AudioQuest Coffee, Belkin Gold USB, Transparent USB (with dCS Vivaldi).
FireWire: AudioQuest FireWire 400 (prototype). Interconnect (balanced):
Kubala-Sosna Elation!, Transparent, AudioQuest Wild Blue. Speaker:
Kubala-Sosna Elation! AC: Kubala-Sosna Elation!, manufacturers' own.
·
Accessories: Target TT-5 equipment racks; Ayre Acoustics Myrtle
Blocks; ASC Tube Traps, RPG Abffusor panels; Shunyata Research Dark Field
cable elevators; Audio Power Industries 116 Mk.ll & PE-1, APC S-15 AC
line conditioners (computers, hard drive). AC power comes from two dedicated
20A circuits, each just 6’ from breaker box.
|
