Scuba Diving Photos
ScubaLab: Reg Review
PERFORMANCE If you want XTX200 performance but are looking to save some cash, check out the XTX50. Except for some cosmetics, the second stages are identical, with the same left/right reversibility, efficient user adjustments, choice of exhaust tees and ComfoBite mouthpiece. The big difference is in the first stage. The XTX50 first stage, while environmentally sealed like the XTX200, also offers a rotating lP port turret with a new fifth lP port perched on top.
Like its big brother, the XTX50 earned perfect scores in Scubalab’s standard breathing-machine tests, and was even able to dip a toe into the muscle-reg realm. In the ocean, test divers rated the reg’s user adjustments as among the best of this test group. It offers minimal bubble interference, an efficient purge and effortless air delivery in all diving positions.
BOTTOM LINE If you like diving top-end regs, but your wallet’s running on the light side, the XTX50 is a great way to enjoy a lot of breathing performance for not a lot of money.
The regulator review is the high point of ScubaLab’s annual gear-test program because it’s when we get to peel back the performance layers on what is arguably the most important piece of equipment in a diver’s bag. Clinical testing took place at Dive Lab, which operates the only nonaffiliated ANSTI breathing machine in the country. Then came the ergonomic trials with a test team in the Gulf of Mexico at a site called Airplane Barge off Clearwater, Florida. The reviews presented here are a cumulative summary.
HOW WE TEST: REGULATORS
Breathing Machine Tests:
>>All regs are tested as received from manufacturers.
>>Regs with user adjustments are adjusted for testing at the no-leak/free-flow point. Regs are tested on the breathing machine in a face-forward position, per industry-testing norms. (Note: Regs breathe better in a facedown position, more typical for a recreational diver.)
>>Following a surface check, each reg is tested at three different breathing rates, known as RMVs (Respiratory Minute Volumes, basically the amount of gas that can be ventilated through the lungs in one minute), at three depths, for a total of four RMV/depth combinations. These breathing rates were chosen to enable us to:
- simulate a recreational diver’s breathing rate.
- conform to recognized industry testing parameters for purposes of comparison.
- surpass normal breathing rates to determine reserve capacity (the ability to continue to deliver gas smoothly and easily, even at extreme depths and breathing rates).
>>Simulator tests are not intended to pass or fail regulators, but rather to scientifically gauge their performance based on controlled conditions.
Ergonomic Tests Explained:
ScubaLab staff evaluates each regulator in the water in 13 basic areas. Performance is tracked by numeric scores (1 to 5 – 1 being Poor, 5 being Excellent) and written comments, recorded at depth, while regs are actually being used.
Ergo Test Categories:
- Ease of breathing, swimming position: How well does the regulator deliver air when moving forward in a standard swimming position?
- Ease of breathing, face-up position: How well does the regulator deliver air when you are at depth and looking up toward the surface?
- Ease of breathing, heads-down position: How well does the regulator deliver air when you are at depth and in an inverted position?
- Wetness, swimming position: How dry does the reg breathe?
- Wetness, heads-down position: When in heads-down and face-up, how dry does the reg breathe?
- Bubble interference, swimming position: Taking into account all regulators have bubble interference to a certain degree, when moving through the water, how well does the reg deflect bubbles from your field of view?
- Bubble interference, stationary position: Taking into account all regs have interference to a certain degree, how well does it deflect bubbles from field of view when stationary?
- Ease of clearing, exhalation method: How much force is required to clear the regulator by exhaling?
- Ease of clearing, using purge button: How difficult is it to find and use the purge? How forceful is it?
- Purge-button flexibility: How stiff or pliable is the purge button/cover, and how efficiently does it clear?
- Comfort of mouthpiece: How comfortable is the mouthpiece?
- Venturi lever adjustment: Is the Venturi lever easy to find and use?
- Breating adjustment knob: Is the adjustment knob easy to find and use? Does it do its job in a reasonable manner?