Hey ladies and gents, let's switch from discussing headphones this week and have a look and listen at some speakers.
You've probably seen speakers like the ones above over the years. These are the "iconic" Gallo Acoustics A'Diva Ti speakers from the UK. These specific ones are probably something like 16 years old and the 5" diameter A'Diva orb (with 3" driver) is in fact the larger of the 2 speakers from Gallo we'll be talking about today.
Here's the smaller 4" diameter (also 3" driver) little brother - the Nucleus Micro. Note that this is the "non-Ti" version which is from the previous generation, made around year 2000 with presumably a different driver. Unlike the stainless steel protective grille of the A'Diva, the fabric grille is easily removed for photography:
In hand, they feel very well made. Solid sealed metal balls weighing about 1.5kg (3.3lbs) for the A'Diva Ti and just under 800gm (~1.8lbs) for the Nucleus Micro.
The larger A'Divas sold for around CAD$300 back in 2005 as you can see on the box (with an on-sale price of CAD$250):
Let's see, this works out to about CAD$350 (~US$290) with inflation today for each of the A'Diva speakers. Certainly not cheap for a pair around US$600. I see that indeed this 6Moons review of the A'Diva Ti listed the price back in 2005 as US$275 each and the Nucleus Micro was a bit less at around US$200 each.
Notice in the picture above how they included a rubber "O-ring" to put under the speaker to prevent the sphere from rolling off your table.
Here's what the back of the speakers looks like. We see the multi-way binding posts that accept standard banana plugs as well as spades and bare wires. They are a little close so one would not want huge wires/connectors plugged in:
|A'Diva Ti, rear.|
|Nucleus Micro, rear.|
Notice the single screw mounting hole that you can use to attach to a stand or wall mount (the hole below the binding posts). If you're using the O-ring on a table and given their light weight, be careful with thick speaker cables! It can be a balancing act using just 14AWG cables as I did. The last thing you want is for the metal ball to roll off a table or land on something like hardwood or tile flooring!
Let's have a look at the impedance and phase graphs for these speakers:
As a single driver, we basically see the main resonance frequency and a gradual increase in impedance into higher frequencies as a result of inductance. For the A'Diva Ti, resonance frequency is around 150Hz and the Nucleus Micro, it's higher up at 230Hz.
Minimum speaker impedance is indeed almost exactly 8Ω as specified by the company; we can see that the EPDR can dip down to a 5Ω equivalent for both. Other than the difference between drivers themselves, the change in the resonance frequency is also a result of the different enclosures - as expected, the larger A'Diva Ti has a lower resonance frequency.
Let's now have a peek at the 2.83V signal sweep at 1m for sensitivity of these orbs:
The graphs above provide a preview into the gated on-axis frequency response which as you can see is reasonably flat between 500Hz to 7kHz for both these speakers.
Okay, let's put the speakers up on the qSpin rig and capture some "CTA-2034-inspired" graphs to get a better look!
|Little Gallo Nucleus Micro ready to go for a (q)Spin...|
I think it goes without saying that the appearance of these speakers is a selling point. As such, all measurements will be with the grille in place. Let's use the 50dB/dec aspect ratio with 50dB Y-axis as standard.
Here's a look at the directivity polar maps for the 2 speakers; horizontal and vertical planes are symmetrical due to the shape so I'll just show the horizontal measurements +/-180°.
Clearly not the most symmetrical looking directivity polar maps I've measured. In particular, the Nucleus Micro got a little nasty and unpredictable up in the higher frequencies beyond the cone's comfort zone. Listening to these speakers within +/-30° would be prudent.
Shifting to the time domain, let's look at the step response and waterfall plots for each speaker:
As you can see in the picture at the very top of this post, I borrowed both a matte black and matte white-colored A'Diva Ti with quite different serial numbers. Here's a frequency sweep to check for consistency between speakers:
Subjective sound quality...
As usual, I listened to these speakers before running the measurements. Here's one of the little Nucleus Micros on my computer workstation desktop:
|Since I'm using bi-wirable banana plugs, note an unused plug peeking from behind.|
Sound clarity was generally good. John Renbourn's guitar work (The Guitar of John Renbourn) sounded "fast", precise, if a bit sonically uninspired without more low-end presence overall (imagine "Seven Up" without decent bass impact on those drums!). While I did not put them in the soundroom with ideal separation distance, the soundstage was pretty good in terms of width and conveying the sense of depth - but one cannot ignore the frequency domain issues as paramount.
|Tiny white Gallo Nucleus Micro in the living room flanking 55" TV. Better soundstage and overall sound than the tinny TV speakers at least. I suspect these days, a decent sound bar like the Yamaha SR-B20A would be quite effective.|
I find these speakers historically interesting because they came out at the turn of the 21st Century. Back in those days (Y2K, 20 years ago), home audio was experiencing a drive towards the surround sound home theater experience. It was a time when Dolby Digital discrete multichannel (AC3) had become inexpensive enough to integrate into consumer-level receivers and DTS was also making its way into homes. Furthermore, SACD and DVD-A were promising "high-resolution" surround as well to entice the audiophile (because they knew "hi-res" stereo barely sounds different than CD even if marketing hype still touted bit-depth and big samplerates!).
Small speakers like these would have been of interest as "lifestyle products" that could be placed out of the way and the audio press would also have been following these Industry changes as there could be money to be made if multichannel took off with audiophiles and mainstream consumers alike.
As "lifestyle products", these little speakers appear to be well made. These days, I see that Gallo Acoustics has added a "bespoke colour service" to spice up the look of these orbs further with custom Pantone and RAL color choices. My wife thought they looked "cute" sitting on my computer desktop but it was obvious to her that the sound was lacking compared to the less expensive Emotiva Airmotiv B1+. I think it's interesting reading the positive "audiophile" reviews written in 6Moons, Part-Time Audiophile, SoundStage!, and CNet in retrospect now that I have these here to listen and think about what was said. The Sound+Vision review is the only one I've seen with measurements of the A'Diva Ti with their -6dB bass roll-off point at 103Hz equivalent to what I also measured.
Obviously, with a small form factor like this there need be no big surprises around the kind of sound these produce. These are small, single-driver, closed, passive dynamic speakers and the results conform to the rules of physics with limited bass extension and frequency range the driver is "comfortable" with reproducing. Compared to good 2-way bookshelves or floorstander speakers, while one might be "surprised" that a speaker of this size could produce sound at a reasonable volume, it's simply not going to be "room filling" in any special way.
Yeah, the company literature will no doubt focus on the single-diver, crossover-less design as being time coherent, a "point-source", and the round shape would reduce baffle diffraction effects. In the big picture, these are IMO minor benefits in the face of poor bass performance if used alone. If we took the high and low -6dB points on the measurements as the realistic frequency limits to these speakers, the A'Diva Ti would have a frequency range of 100Hz to 15kHz while the Nucleus Micro covers 200Hz to 14kHz. Since the content between 100-200Hz is rather important (you don't need to be a Golden Ear to hear this ;-), between the two, the A'Diva Ti sounds significantly better even though interestingly, I found that it had a bit more harmonic distortion in the measurements (both black and white speakers showed this tendency).
I would obviously insist on pairing these with bass/sub-woofers (especially the Nucleus Micro) if you really want the sound to resemble anything like "high fidelity". Back in the day, these small speakers were often paired with the Gallo TR-1 sub with 10" driver, 100Wrms "active sub" with claimed frequency response of 20-180Hz. I think my friend AudioPhil whom I borrowed the little Nucleus Micros from has one of these and maybe at some point I'll have a listen to the combination of these "satellite" speakers integrated with the matching bass/sub. My concern especially with the Nucleus Micro is that the limited low-frequency performance requires the woofer/sub to fill in too much of the content essentially to 200Hz and thus results in easy localization of the bass module.
Even as surround speakers, I would prefer satellites having reasonable frequency response down to 80-100Hz. The only exception I would make would be Atmos add-on height effect channels (like the ELAC Debut 2.0 A4.2 previously reviewed/measured).
These days, one could still buy updated versions of these speakers. Presumably there have been improvements to the drivers although specs like frequency response have not changed all that much from what I see. The Gallo Micro is available for around US$200 still. The newest versions come with the "SE" designation and have a 4Ω impedance rating rather than 8Ω - the Micro SE and A'Diva SE.