Sennheiser XSw12

[STCM_Tech]

Hi Guys

I am a school technician and as a school we have links with a nearby church, they have asked me on thoughts about radio mics as they have had lots of trouble with their existing ones getting lots of interference. They have asked my thoughts on the Sennheiser XSw12, I haven't used these and wondered if anyone had any experience. Obviously they need licenses but they know this as they are moving from open frequency mics where they have had lots of interference. Anything else in that price range thats better? We use the Sennheiser G3's and love them so I like the fact they are going with Sennheisers too but just wondering if this cheaper model are any good. Would love to know your thoughts.

ThanksWill

[MarkBarl]

I haven't used the XS range so can't comment on that. However, if they do get some, get them to go for the Range E version. Remember that there is now Channel 65 and Part of 66 that are available on the shared licence. These also operate in Ch70. They can try them in channel 70, if OK great, no need for licence. If they need licence then covered by the shared licence at about £75 per year. Looking at the frequency sheet for the XS range E, any of the available frequency presets are suitable either as licence exempt ones or the PMSE Ch65 &66.

[Peter F]

I would be inclined to suggest the church does a bit of research into what is causing the interference first.

 

How many sets are they using?

Are the frequencies compatible with each other (is the interference intermodulation between their own radio mics)?

Who else is using radio mics nearby?

Where are their antenna located?

 

Cheers,

 

Peter

[timsabre]

Do you know what they have now? And what the nature of their "interference" problems are? Is it really other users on the same channels or might it be other radio problems?

 

We have some XS at our church (on ch70) and they are fine, the main problem is users getting confused with the mute button (lots of rummaging around in clothing to find out why it isn't working). Also the supplied mic clip (for the lapel type) is rubbish.

 

We also have the Trantec S4.4 (same as the discontinued Sennheiser Freeport) which just have a single on/off switch and we have a lot less problems with user error. They are lower quality but for church speech applications they are fine. But you can only run 4 of those together. The S4.4 handhelds are not so good, plasticky and lots of handling noise.

[STCM_Tech]

They don't know whats causing the interference, they have had the same mics for years with no trouble and then over the last half a year they have got more and more bad interference, its very sporadic interference.  They meet in a primary school so could there be the potential for the school to have something on their site that is interfering? There is nowhere else nearby that would use radio mics. 

[Peter F]

They don't know whats causing the interference, they have had the same mics for years with no trouble and then over the last half a year they have got more and more bad interference, its very sporadic interference.

 

I'd be checking to see if someone has helpfully retuned them so they are now interfering with each other.

 

Cheers,

 

Peter

[timsabre]

Or it could be a dodgy heating thermostat arcing, or anything random like that, might not be anything to do with the radio mics at all.

 

I would agree with the others that just going out and buying new mics is a risky strategy that may not help the problem, and it would be better to get someone in who can identify what is going on.

If this is a Church of England church, the local diocese should have a sound advisor who will be able to help with this.

 

Do you know what the interference sounds like?

[Shez]

My limited observations of that environment suggest that it's common for the user of the mic to switch off the pack when not speaking and switch it on again when needed. If they're used like that in this particular church, does the interference only occur when the pack is switched off? That wouldn't be surprising as a more distant transmission would be swamped by the local mic when it's on but would be able to break through occasionally in its absence. If the receiver has an adjustable squelch, that might help matters. If the replacement system has an audio mute, rather than an RF mute (power off), that would also be useful. It all comes down to the exact nature of this interference.

[sandall]

From experience of troubleshooting church systems the word "interference" can mean almost anything, frequently just a crackling lapel mic connector, but the suggestions by Peter, Shez & Tim are all good ones to check.

[STCM_Tech]

The interference only happened when the mics were on. They have used two of our G3's for the last two Sundays and had no problems at all

[timsabre]

As Sandall says it could be something as simple as a bad connection on the lapel mic cable - they do go grotty eventually as sweat gets into them.

This normally manifests as a loud crackling noise - which could be described as "interference".

 

On the other hand, hiss/fuzz noise would indicate some sort of radio issue.

[sandall]

Unless I've missed it you haven't said what make / model / band the offending mics are.

[richardash1981]

Or it could be a dodgy heating thermostat arcing, or anything random like that, might not be anything to do with the radio mics at all.

The worst case I encountered was a fairly expensive G3 Ch38 installation which had (for fear of listed building rules I think) put the antennas inside the receiver rack, flat against the underside of the (wooden) lid. There was then a laptop on top of the lid to drive the projector. It was all fine with the transmitters on, but if anyone switched off whilst the laptop was on, a torrent of noise poured out of the system.

 

I would suspect defective contact somewhere as a likely cause of crackles / weak signal / incorrect squelch level. I have fixed the following on my church's Trantec S1000 lapel system over the years:

• Defective transmit antenna (flexes at the pack end until it breaks). Solder it back on and use heatshrink to reduce flexing.
• Broken conductors inside the mic cable at the beltpack end (LEMO connector). Shorten by 60mm, re-solder with heatshrink if room
• Broken connection in the mic capsule end. Fiddly re-wire. In the end put a cheap CPC mic on as it sounds better, kept original as spare.
• DC power input jack unsoldered from receiver PCB. Re-solder inside
• Receiver squelch pot (white control pokes out the back of the receiver) unsoldered from PCB. Re-solder inside
• Receiver antenna no longer connected to PCB. Antenna is bolted to the chassis and then a solder tag and length of bare wire to the PCB. Rotating antenna had gradually pulled the wire out of it's solder joint at the PCB end. Loosen nut, adjust back to position, re-solder and tighten nut up to stop it happening again.

Thank goodness for an easy to dismantle receiver! This gets set up and packed down each Sunday so does see a lot of connector mating cycles etc.

[Stuart91]

The worst case I encountered was a fairly expensive G3 Ch38 installation which had (for fear of listed building rules I think) put the antennas inside the receiver rack, flat against the underside of the (wooden) lid. There was then a laptop on top of the lid to drive the projector.

 

I've seen a fairly expensive installation (done by a "reputable" company) that had the receivers inside a substantial metal rack.Nonetheless the job had been signed off and paid for, even though the radio mics weren't even functional. In an empty building, they didn't work 10ft away from the receiver, and the stage was more like 60ft away.