Zu Undertone Subwoofer

When you need quiet, agile, deep and powerful bass without all the awful subwoofer noises. Undertone is designed to compliment high-resolution loudspeakers and gives excellent integration of sub-contrabass content, be it music or film.

Undertone is designed to compliment high-resolution loudspeakers and gives excellent integration of sub-contrabass content, be it film scores or harder yet, music. If you are looking for an agile, deep and powerful subwoofer system, that is flexible and incredibly musical, Undertone is worth your consideration (and maybe even your hard-earned money).

Undertone is designed to compliment playback systems that have great sound down to about the kick drum (50Hz or so) but lack a sense of glory and tranquility that deep bass done right can give. The stereo and home theater systems I’m referring to usually feature large monitors or medium to large floor-standing loudspeakers that get you a good impression of bass but lack sincere detail of body and weight. Undertone is for those searching for that missing majesty and space; for systems that need that added tone in the foundation of big/deep music and soundscapes—and without that slow and foggy one-note sound of a modern under-built subwoofer.

Undertone features the same electronics and awesome Eminence LAB-12 sub-woofer driver and tuning we developed for our Definition Mk.IV loudspeaker, but strips out the high cost of the machined aluminum alloy electronics enclosure and massive base. Undertone is all about giving you near state-of-the-art subwoofer performance for a very reasonable amount of cash. For those that have heard our Definition Mk.IV loudspeaker, the performance is pretty close, getting you about 85% of the quality of deep bass sound and100% of the power.

Undertone Quick Specs

Height: (with feet) 25″ [635cm]
Footprint: 15 x 15″ [38 x 38cm]
Weight: 68 pounds [31kg] each
Bandwidth: 14–80Hz

Line-Level Input: yes, RCA (left and right summing)
Sub Line-Level Input: yes, RCA
Speaker-Level Input: yes, 5-way binding posts (L/R summing)

Tunability: very
DSP Bypass: yes, switched for those that want to integrate more elaborate signal processing but desire to take advantage of the excellent amplification of Undertone.

Driver: the awesome Eminence LAB-12
Plate Amp: Zu Subwoofer Plate Amp Mk.II
Power: Hypex UCD 400

Hypex amp module made in Netherlands
Eminence LAB-12 made in Eminence, Kentucky, U.S.A.
Balance of the system designed and made In Ogden, Utah, U.S.A.

Cabinet Construction

Undertone is made from North American high-density composite wood plate (comp-60) and is machined on state-of-the-art CNC mills in Preston, Idaho. Undertone uses real wood veneer pressed at the plywood factory (also in Idaho) and is not laid-up post cabinet assembly. This ensures your finish will not lift or warp, and it yields the flattest surfaces and tightest seams. For glue, it’s Titebond-III, for the highest joint strength and a lifetime of unfailing, moisture-proof service.

Colors and Finish Options

Standard satin varnish offerings are: Ghost Black Maple | Gray Maple | Sangria Maple | Electric Blue Maple Ghost Black Walnut | Honey Walnut

The above standards are top coated by UV protecting premium grade conversion varnish. All finish work is done in Zu’s custom finish shop in Ogden. Other finishes are available through the Zu custom shop; inquire for pricing.

Acoustic Technology

Old-school, in all the best ways; Undertone is a medium compliance, sealed enclosure system where the restorative driver forces are shared between the driver’s suspension (spider is primary) and the air in the cabinet. Undertone continues our tradition of making quick, details “sealed” subwoofers.

Subwoofer Plate-Amp Detail

Undertone’s electronics really perform and offer just enough tunability to be useful and not overwhelming. The amplifying module is the highly regarded Hypex UcD 400. And Undertone’s electronics were designed to accepts unfiltered left and right RCA line-level inputs, home theater sub-woofer signal, and unfiltered loudspeaker-level feeds (taping only signal). Undertone is also able to integrate with high efficiency loudspeakers like ours without having to jump through hoops with gain and volume matching. Some design highlights include:

Hypex UCD 400 amp module
ALPS pots for volume and signal processing control
Zu Event #28 hookup wire on signal feeds
3M IDC adhesive locking terminals
Panduit disconnect terminals
Neutrik RCA jacks (sound great and as tough as it gets)
Extra large toroidal transformer and overbuilt linear power supply
Machined 1/4″ [6.3mm] 6061 aluminum amp plate
Laser engraved graphics and detail
Custom machined knobs
Insulated 5-way binding posts
Gain structure of preamp section is designed to accommodate both low and high-efficiency loudspeakers

Tips On Getting Great Sound From Undertone

Undertone subwoofers only get two days of play before leaving the factory, and while it is high-intensity and shakes the bugs out, you will find Undertone to sound better after a few weeks of heavy play. And of note, if they are transported in cold weather, they take several days to “warm up” and return to giving you their best.

Make sure you have a 3/4″ [20mm] or more gap between the bottom of the loudspeakers and the floor; the down-firing woofer needs a bit of room to breath. Ball-end footers (for use with hard surface flooring) as well as long spikes (to be used to punch through and anchor the subwoofer through carpets and rugs) are included.