Q: “I’m interested in buying a Shure wireless system, but can’t decide if I should get the SLX or ULX. What’s the difference between the two?”
A: The most important difference between ULX and SLX wireless systems is the total number of systems you can use simultaneously. The SLX systems are available in three 24MHz-wide frequency ranges: H5 (518-542MHz), J3 (572-596MHz), and L4 (638-662MHz). Within each individual band you can operate up to 12 total systems. If you employ all three bands at the same time, then a maximum of 20 systems can be operated.
ULX systems are available in two 36MHz-wide frequency ranges: J1 (554-590MHz), and M1 (662-698MHz). Each of these bands is the capable of supporting up to 20 systems. By utilizing both bands simultaneously, it’s possible to operate up to 40 systems. So, if you need 20 or fewer systems running at the same time, SLX is a lower cost solution that still offers many of the features of the higher priced ULX (Audio Reference Companding, Automatic Frequency Scan, etc.)
Another deciding factor has to do with remote antennas. When you use remote antennas, you often need to add in-line amplifiers to compensate for loss from the antenna cable. The power for in-line amplifiers usually comes from the wireless receiver’s antenna inputs. The SLX4 receiver does not supply this power. Remote antenna amplifiers can be used with SLX, but only if a Shure UA844 antenna splitter/power distribution system is used. ULX receivers (both Standard and Professional) do supply power for remote amplifiers directly from the antenna inputs on the back of the receivers. Therefore, if you need to power remote antenna amplifiers directly from a receiver, then ULX is your choice.
One last consideration is battery cost. SLX transmitters get about eight hours of usage out of two “AA” batteries. ULX transmitters use one 9-volt battery and also get around eight hours of life. Two “AA” batteries usually cost about half the price of one 9-volt battery. This could result in significant savings in the long run. If battery cost is an issue, consider using SLX.