Confused about frequency choices for first IEM Transmitter/Receiver system purchase....

[jeffincltnc]

I'm going to be getting my own wireless transmitter/receiver system for the first time (I've used band systems a lot, but never bought my own system).

 

I'm kind of liking the new Sennheiser XSW IEM system for the money ($599) which is a very simplified and easy to get started package, competes against the Shure PSM300 which has more features but more money, stereo and I like Sennheiser for reliability above the cheaper stuff like XVive and Galaxy Audio... so it checks the boxes.

 

I don't know how to select a frequency.  I haven't found much guidance from Sennheiser as to how to pick a frequency for the system of your choice, and you have to specify from the following models - all at the same price/package:

 

Frequency range

A 476-500 MHz

B 572-596 MHz

C 662-686 MHz

E 823,2-831,8 MHz

K 925,2-937,3 MHz

 

What should I be considering at getting the right frequency package?  I guess I know that I want to avoid WiFi interference with an iPad based mixing app for my XR18, but other than that, I don't know what those frequencies are to avoid anyway.

 

The one thing I know about this forum is that someone will have an easy to understand answer for me.  (and at least one person will have a PhD in radio frequency physics and give a scientific explanation of what is happening and how interference is created. 🙂. )

[Tom Williams]

In general, lower carrier frequencies (presuming same signal amplitude) are less likely to be blocked by intervening objects.  In particular, I recommend that people avoid anything in the 2.4 GHz band.  There's just too much other stuff (Bluetooth, old Wi-Fi, and microwave oven leakage) happening in that band.

 

I went with 500-600 MHz for my Keytar -> PA, 600-650 MHz for my Monitor -> IEMs.

 

[analogika]

I don't know how it is in the US, but in Europe, more and more frequency blocks that have been used for private wireless devices will go/have gone on auction for cellular use (what makes it even worse is that these aren't necessarily European policies, but are handled differently from country to country). 

 

There was a LOT of reading involved, concerning future frequency allocation plans by the various equivalents to the FCC. 

 

And then finding a system that would not only reliably and legally work here in Germany for the next decade or so at least, but also in the countries I'm most likely to be playing… 

[TJ Cornish]

Head over to the Shure Wireless Frequency Finder and type in your location. This will show you how much RF bandwidth is available in a city in each band.

 

A couple general thoughts - wireless spectrum is scarce. The TV band used to be big and open, but with the transition to digital TV transmitters that produce far less unwanted RF noise out of their intended channel and with cellular data gobbling up more and more spectrum, there is less room.  If you’re shopping for just a few channels, you will be fine if you choose a band with the fewest TV transmitters operating in it.

 

Also keep in mind that depending on what is going on around you, you will have to either periodically rescan for an available frequency, or if you’re part of a larger system, coordinate with other equipment.

[TJ Cornish]

8 hours ago, Tom Williams said:

In general, lower carrier frequencies (presuming same signal amplitude) are less likely to be blocked by intervening objects.  In particular, I recommend that people avoid anything in the 2.4 GHz band.  There's just too much other stuff (Bluetooth, old Wi-Fi, and microwave oven leakage) happening in that band.

 

I went with 500-600 MHz for my Keytar -> PA, 600-650 MHz for my Monitor -> IEMs.

 

FYI, in the USA, pretty much anything above 600MHz is illegal as of 2020. I haven’t heard lately, but until recently the 900MHz stuff had other interference issues.

[Tom Williams]

18 hours ago, TJ Cornish said:

FYI, in the USA, pretty much anything above 600MHz is illegal as of 2020. I haven’t heard lately, but until recently the 900MHz stuff had other interference issues.

Good clarification.  I was posting from memory (always risky).  I researched that pretty heavily at the time I purchased, and I am pretty sure I stayed in the allowable areas such as 615 MHz or 660 (at a low RSSI level).   My main point stands: avoid 2.4 GHz.  Go lower. 

 

Regarding 900 MHz, it's like the old joke: No one goes to that restaurant any more, 'cuz it's too crowded.   But I'd take the 902-928 MHz band over 2.4 GHz in a heartbeat.