Floor-standing Speakers

Anthony Gallo Acoustics Reference 3.5 Speakers



Last year, I also reviewed the Reference Strada stand mounted speakers with the separate TR-3 subwoofer. I absolutely loved those speakers, which clearly outperformed my Reference 3.1s. The new Reference 3.5s share many features with both speakers. The module containing the midrange and tweeters is identical between the Reference 3.5 and Strada. This module is mounted in a cast-aluminum strut that is the same as the previous Reference 3.1. This is combined with a new, ceramic cone dual voice coil woofer in a spun stainless steel enclosure.

This is a similar configuration to the previous 3.1, but with a brand new driver and re-designed enclosure. The driver is the same as used in the TR-3 subwoofer. The dual voice coils are configured the same as in the previous 3.1. One voice coil is connected to the main binding posts through a ~125 Hz low pass crossover. The other voice coil is connected to a second pair of binding posts on the speaker with no crossover present. This allows the use of an outboard subwoofer amp (with external crossover) to supplement the full range amplifier. This allows the sub amp to reinforce the bass response, extending all the way down to 20 Hz and allowing for room tuning. The Gallo Reference SA amplifier has continuously adjustable volume, crossover frequency for left and right channels independently, and provides 240 W per channel of power. Since I already had the Reference SA amp, I used it with the new 3.5s.

As with the 3.1, the 3.5 uses an almost-crossoverless design. The woofer and midrange are crossed-over with  a simple 125 Hz filter. The midrange and tweeter use no electrical crossover. The midranges are carefully designed to intrinsically roll-off at higher frequencies without break-up or other problems. The midrange drivers are carbon fiber cone units that are bespoke for Gallo. Unlike the Reference 3.1, the 3.5 uses permanently mounted mesh grilles on the midranges. These have been carefully designed to optimize the loading on the driver. The cylindrical tweeter also uses no crossover, with the band limited via the design of the driver. This tweeter, shared with the Reference Strada, is a brand new driver that shares the cylindrical piezo film architecture of the unit in the 3.1, but is completely new. It too uses a new, mesh grille that also optimizes the loading of the driver.

The new speaker has a redesigned base. Rather than an MDF base with carpet spikes as used in the Reference 3.1, the 3.5 uses a heavy phenolic resin base with a polymer pad for decoupling from the floor. The designer, Anthony Gallo, says this material effectively decouples the speaker from the floor, and makes the speaker perform more consistently on a variety of floor types. With the previous spikes, the speaker would sound very good when placed on a very sturdy, vibration free floor, but would suffer on more flimsy platforms. The new, vibration damping material allows more optimal performance on a wider variety of surfaces.

While looking similar, the only component shared between the Reference 3.1 and 3.5 is the cast aluminum strut that is the backbone for the speaker. This strut is cast in two halves, and then welded together, ground smooth and painted with a thick, textured paint. This is the single most expensive component of the loudspeaker, and is primarily responsible for the price increase between the 3.1 and 3.5. Anthony Gallo explained that he had locked in the price on this component for the Reference 3.1, but the company that produces the strut had taken significant losses because of a much higher than expected reject rate. The company then passed along a price increase to Gallo that would have resulted in a huge price increase on the Reference 3.1. Rather than pass on this big increase in price with no improvement in performance, Gallo set out to redesign the 3.1 from the ground up to make a speaker worthy of the increased cost. The result is the 3.5, with every component redesigned and significantly upgraded with the exception of the aluminum strut that started the whole process.

The Reference 3.5 contains a whole alphabet soup of technologies that Gallo has developed. Some of these are used in all Gallo speakers, others make their debut in the 3.5. The first is S2. This is a fiber flake material made from a polyolefin plastic. This material fills all the driver enclosures and the entire strut assembly the driver enclosures are mounted to. This material helps damp standing waves, stops reflections, and acts as mass loading for the driver. The acoustic back wave coming from the driver couples to this material, and the material resists motion, creating damping. All Gallo speakers are filled with this material, and have been for some time.

OPT Level 1 is another technology that helps with time alignment of the drivers to optimize impulse response. This technology has to do with the mechanical mounting of the drivers. Everything, whether it likes it or not, is subject to Newton's third law of motion: for every action there is an equal and opposite reaction. How does this come into play with a speaker? Well, when the speaker cone is pushed forward by the magnet, the speaker basket is pushed backwards. If the speaker basket can move, it will. This motion will result in time domain smearing of a transient. Anthony Gallo of course realized that no matter how hard one might try to make the driver mounting rigid, the speaker basket will always move, at least a little bit. OPT Level 1 tunes the materials and design of the driver mounts so they all move by the same amount under this reaction force, optimizing the transient response.

OPT Level 2 is a new technology that is new for the Reference 3.5. For years, Anthony Gallo has been annoyed that the sound of his speakers seemed to change based on how the speaker cables were routed, and what kind of floor covering those cables were sitting on. He surmised that this effect was caused by the electric field created by the musical signal in the speaker cable interacting with the floor (which is a dielectric). OPT Level 2 uses special speaker cables that have a helical wire wrapped around the two signal carrying conductors. This wire is attached to the positive amplifier terminal at the amplifier, but is left as an open circuit at the opposite end. The positively charged wire (which carries no current) is meant to prevent the interaction of the signal carrying conductors from interacting with the outside dielectric (i.e. the carpet). A banana jack on the outside of the speaker just above the binding posts mates with this wire coming out of the Gallo OPT Level 2 speaker cable and continues the shielding into the speaker, all the way to the tweeter. The speaker is still perfectly usable with normal speaker cable. Jumpers are supplied so the user can connect the positive amp terminal to the banana jack, giving the OPT Level 2 improvements inside the speaker with normal speaker cable. For this review, Gallo supplied their OPT Level 2 cables, which I used for some of the review. I switched back to my normal cables (used with the supplied jumper) for the balance of the review so I could compare.

A note for current Reference 3.1 owners. Gallo will upgrade your 3.1s to 3.5s for $3200. This currently is an exchange program, meaning people who send back their 3.1s will get a brand new pair of 3.5s. In the future, the 3.1s may be recycled. The only part that will be used is the aluminum strut, but as mentioned before that's the single most expensive part of the speakers to build. If you're interested in this possibility, you should contact Anthony Gallo Acoustics directly, rather than your original dealer.