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Hiss/noise with AT M2 (or other wireless in-ear)

bcalbass

bcalbass

Apr 30, 2012
120
77
Northern California
#1
So I'm finally gigging again and looking to go wireless with my in-ears. I'm hoping the more experienced folks will have some insight into the additional noise (if any) that gets introduced with wireless in-ears.

Currently, I run my in-ears from a Rolls PM351. It's dead quiet (unless I really crank the levels beyond what I would ever use comfortably) and the fidelity of the bass sound is perfect. I can hear every little nuance and blemish.

I just picked up an Audio Technica M2 wireless system. I haven't had a chance to use it anywhere outside of the house yet. I run a Y cable (stereo to 2 x mono) from the Rolls headphone out to the L & R in on the AT M2. Even with nothing hooked up, there is a low hiss audible when using the M2 wireless pack. With the Rolls and bass hooked up, when playing notes on the bass the hiss comes up slightly more - almost like a noise gate was involved. Finally, I can tell that the M2 is altering the bass sound somewhat, such as hard attacks getting a little clip/pop artifact (almost like the M2 had a compressor on it) even though the M2 input isn't getting anywhere close to clipping. Same attack and level wired to the Rolls, and I can hear the full attack sound without any artifacts.

So my question is: does this sound normal for the M2? Or for similar wireless units like the Shure PSM200 or others? Or is this M2 defective maybe? I really like the sound I get wired from the Rolls, but I really want to go wireless on the stage. Any help or ideas would be greatly appreciated.
 
#2
You are hearing the limiter active on the belt pack. Turn off the appropriate dip switch and try it without the limiter and your attack should be fine.

Also, your hiss might be coming from the y cable. There is no need for it with the M2, you can run one signal into one side and the appropriate dip stitch setting on the pack will sum it into both L and R ears. Give it a shot. My M2 has no hiss, so there is something going on here.
 
#3
Good to know the limiter is working, at least. I'll put up with the slight change it's making in the sound if it can save my ears from a signal spike.

Edit:
So there was no change with a different cable. The Y-cable I was using was an insert cable. This time I tried a regular instrument cable, as well as a 1/8" TRS cable with a 1/4" adapter on the M2 end, with the belt pack in mono mode. They all sound identical.

Maybe this is a better question to ask: how silent should the belt pack be when switched on vs off?

With nothing hooked up, transmitter turned off - when I switch the belt pack on, there is a deep pop, and then an audible hiss. It's not very loud, but it's there and very obvious when you switch the pack back off (another deep pop, then silence). It is this hiss that gets just a bit louder when a bass note is played, and then goes back down when I stop.
 
#4
Sub'd. I'm interested to learn more about this. Like the OP, my 1964 Ears VStage 6 IEMS are dead silent when I use them with the Rolls PM351, or plug them directly into an iPad or my PC for mixing and mastering. I don't have a wireless unit for the IEMs but am thinking about this. Injecting hiss into the signal chain would be a real drag, especially with nice quality IEMs. Besides, my bass and music ain't hissy! :)
 
#6
I have the same pop when I turn on my M2 unit I just turn it on first then plug in my IEM's. No noticeable extra noise though it's a nice unit I've had it on the road for over 3 years with no problems at all. I have the Line6 wireless too for my bass and love that both use AA batteries.
 
#7
Thanks for the replies. It's helpful to compare what other people are hearing.

The hiss is noticeable if I play bass solo, but can't be heard when I add another audio source like an ipod to play along. I'm going to try to do some more in depth A/B comparisons with other headphones and whatever audio devices I've got around. I'm starting to think maybe it's just the M2 having a little inherent hiss combined with really sensitive custom in-ears.
 
#8
it can also be power...although power is more likely to generate a hum, it can also create a hiss...

TBH my initial thoughts were there y-cable...but have you tried using the XLR connections...

also when you say hiss, do you only hear it when you play? what about when you don't play? if its only when you play would it sound like a light distorted/crackling type hiss noise...?
 
#9
Big_Daws said:
it can also be power...although power is more likely to generate a hum, it can also create a hiss...
Click to expand...

Good point. I will remember that when troubleshooting hum/hiss. But...

also when you say hiss, do you only hear it when you play?
Click to expand...

It is there even with just the wireless pack turned on by itself. No transmitter on, nothing plugged in. I even turned off all WIFI, bluetooth, etc in the house. Also tried different batteries (new Duracells vs Eneloop rechargeables).
 
#10
ok...i was just trying to figure out of it was on the audio signal only or in the background all the time...

it does kinda make sense without the transmitter on as you may be hearing the receiver looking for audio, but should theoretically disappear when you receive sync...if not then try a different location, or even different headphones/earbuds...see if that replicates..
 
#11
Alright, so the hiss IS different with different headphones/buds. My custom in-ears make the hiss seem the loudest, but everything else I have (Sony cans, some non-custom earbuds) also show that the M2 hiss is louder than any other audio device I have.

My custom in-ears also let me run the M2 and other audio sources at lower volume settings than my other headphones. So maybe this is an issue of my in-ears not being a good match for the M2 because they are more sensitive to picking up the inherent hiss that is there?
 
#13
The hiss is due to either improper gain structure by not hitting the transmitter hard enough or from a noisy radio signal and/or driving the amplifier in the receiver full boat. Keep in mind the transmitter that sends your favorite FM radio station to your car cost hundreds of thousands of dollars. The one sending audio to your IEM's costs a few hundred dollars.

When set up properly, and using quality headphones, the M2 is about the same as the Shure PSM200, not really any better, not really any worse, and yes better than Carvin all day long. The secret to a good clean IEM mix is to only put in what you need, you don't need bonecrunching in your ears, you just need to hear as much of what you need to hear. I don't need the entire kit, just kit, snare and hat, and I really don't need more of the guitarists that needed for cues which leaves pplenty of room for my vocals and bass and enough of everyone else's vocals to blend harmonies. Drive it strong out the console, don't let your input clip at the receiver. I run my pack full boat and control the levels using an iPad with my Presonus. I do get some background hiss when there isn't something musical covering that spectrum, but it is minimal for my needs.
 
#14
I've been sidetracked lately, but I wanted to close the loop on this, as much as I can. I have not been able to find another M2 to compare with, which would be the way to solve this once and for all. In the end, I returned the unit.

Thanks, keithway, for another perspective. I think I was getting a combination of:
- a unit that had louder hiss/noise in its circuitry than normal
- very sensitive IEM's that that picked up that noise more easily than the crappy buds included with the unit
- the fact that the M2 is a good, but like keithwah said, ultimately low-end (for wireless IEM) piece of gear

I say the last part because, although I haven't been able to find another M2 in stock anywhere to test, I did manage to find a PSM200. And though the PSM200 did NOT exhibit the same hiss when just idling with no signal, it did exhibit other audio glitches and annoyances when I tested it. For now I'm staying wired, and definitely plan to test any wireless IEM unit before deciding on it. Thanks everyone for sharing their experience and ideas.
 
#15
This loop may be closed, but I own the Audio Technica M2 wireless IEM system and use good quality Westone ear buds. There is a slight hiss with the beltpack receiver turned on, (with or without the transmitter powered up), but it's never bothered me in the slightest. In fact the hiss reminds me that the beltpack is powered on and it reminds me to turn off and preserve batteries between sets. I've had this for about two years and am really happy with it. We've had just two stereo mixes that the band shares and that's been a bit of a challenge, but I've just bought an additional transmitter and am pumped about having my own mix for the first time. You can't beat IEM's when it comes to vocal accuracy. Can't ever imagine going back to floor wedges.
 
#16
Just purchased my rolls pm 351 today. I hooked it up properly to my knowledge as there are a few videos on youtube and such... but when I plugged the power supply in the green light was flashing and the mix thru my shure 215 buds was cutting in and out...


My question? ??

Did my local shop give me the wrong power supply.. I noticed I was also able to adjust the mic line and hear a shift in volume without having a mic in the input. ..any help would be appreciated. . This is all new to me...
 

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