Systems ListJTR SpeakersJTR Orbit Shifter Pro

ManufactureJTR Speakers
System typeHorn
Driver Size18 "
Number of drivers1
Internal volume13 ft3
External volume18.75 ft3
Dimentions (Width × Height × Depth)45 " × 22.5 " × 32 "
Weight185 lbs
Aprox. Price$1799 USD


The Orbit Shifter Pro is JTR’s large format subwoofer for high output sound reinforcement and playback. It is a big cabinet measuring 45x22.5x32” and weighing in at 185 lbs, but comparable in size to a typical dual 18” bass reflex. The design is a folded, front loaded bass horn, utilizing a heavy duty, proprietary 18” driver, which is  designed and assembled in the USA. The driver is said to have a very high BL^2/Re of 256 and also a very large xmax rating of 30mm one way. It accounts for a significant portion of the 185lb weight of the OS-Pro. The cabinet is a tall slim design with the mouth of the horn firing forwards from one of the 45x22.5” panels. Construction of the cabinet is composed of 15mm void free BB plywood with a tough Line-X coating for protection. The grille is a 16 gauge, perforated and coated steel. The cabinet features handles integrated into the top and back, a standard pole mount and also a set of heavy duty casters which allow the OS-Pro to be easily moved by one person. Input connections are via Neutrik Speakon STX. The cabinet is also designed and manufactured in the USA. The nominal impedance of the cab is available as 2, 4 or 8 ohms. The system is available passive as tested here or as a powered unit with an internal SpeakerPower Torpedo amplifier. The passive cabinet is offered at $1799 direct while the powered version carries a $1300 up charge.

Measurements taken of the OS-Pro show it to match the basic specs listed by JTR quite closely which is always a good sign. The system sensitivity matched up almost perfectly with an average of about 103dB over the 35-115Hz range. The effective extension of the system appeared to be a bit better than suggested by the specs on the JTR website with strong output down to the 30Hz bandwidth. Overall the OS-Pro is quite well behaved judging from the measurements. Obviously this is a loud cabinet with the potential for peaks of near 135dB at 2 meters outdoors when using an amplifier rated at the maximum recommended 4000w rms. With the K20 amplifier being utilized for the burst testing being rated for about 4x the recommended maximum power, the OS-Pro produced some astounding short term peaks of around 140dB over the 50-125Hz bandwidth. That is measured at 2 meters, is outdoors and is NOT a peak number. Obviously one would never apply that much amplifier to a single OS-Pro in regular use due to the risk of burning up the voice coils with too much duty cycle. However a more “practical” amplifier with a rating in the 2000 to 4000w range is still going to make a lot of noise.  A few of these OS-Pro cabs with a big amp or two will definitely bring the party. Additionally, once the high pass filter is in place, the OS-Pro system has to be driven very hard in order to get it to make any bad noises. With the recommended amplifier size it is possible that the amplifier will give out first. Compared to the plethora of dual 18” bass reflex cabinets available around this price range, the OS-Pro offers something a bit different with its horn loaded design and US manufacture.