I was looking at those. The company discussed sending me some a year back, I hoped to do a little field test on them, thus, pass on a bit more info for us here. Never heard back from them so I moved on... They look pretty cool.

My active monitors are very quiet. What does your system sound like with headphones? Can you hear the same sound in the headphones? If so, the noise is coming from your system, if the noise is gone with the HP on, then your monitors are noisy.

Either way, your monitoring should be dead quiet in a pro world.

Thanks for your response, audiokid.

I just wanted to inform you that I contacted Andy Munro directly (because sE electronics didn't answer me too...) and he immediately answered me (wow, that can be called customer support! :)

"The background noise from the amplifier is about 90dB below the standard reference level (0dBu) and there is 30dB of headroom above that. This means in normal mixing the noise is well below the dynamic range of the system. At a distance of 1 to 1.5 metres the noise should be inaudible but if it is irritating to you then perhaps it is louder than normal. We are looking at the power supply with a view to reducing the noise to zero but this will take a little time. I will get in touch with you as soon as I know if that is possible"

Great :)

So if you're not sitting directly in front of them (as I do - 40cm away from the drivers)... you get great monitors for a low price relative to that kind of sound quality (they sound brilliant, it's crazy... - the bass response is a dream but also the HF is great. You get a feeling like sitting next to the musician. It's more like a 3d/depth hearing experience of stereo audio content without any colorization of the sound. Its neutral/linear. They are my first monitors but I can't imagine a better audio playback quality. It's like the reality while listening to HQ recordings. For sure, bad recordings sound exactly as bad as they were mastered ;) Btw: These are the frist speakers where I can clearly hear a difference between 96khz sampling rate and 192khz sampling rate. Maybe because they are extremely time accurate.

Yeah, but if you sit directly in front of them, the background noise sounds a little bit nasty when not playing music. But maybe Andy will fix that issue too. This would make them the perfect speakers for me.

I try to stay in contact with Andy and will provide more info here as soon as I receive feedback.

Thanks & kind regards,
Aron

If what you are hearing is white noise (it will sound like a hiss), then that isn't the power supply, it's the input stage of the drive amplifier. Your new friend Andy Munro should try some lower-noise integrated circuits in there, or else re-configure the input.

I got called in to sort out a very similar active monitor problem (different manufacturer), and it turned on whether the equivalent noise generators for each input were inside the feedback loop or outside it. Changing to an inverting configuration for the amplifier and restoring the polarity by swapping the loudspeaker terminals made the system quieter without any measurable difference to the audio performance. Theoretically there should have been a small increase in the noise, but some things don't always go according to theory.

Most of these new amplifiers are utilizing computer style switching power supplies. They are no longer linear supplies. And they have clocking noise. Personally, I don't think you'll ever get rid of that noise? If it's 90 DB down with 30 DB more headroom, it's at the theoretical limit of thermal noise. Yeah, it should just be white noise. But with switching power supplies, all bets are off. They're convenient, they're inexpensive, they are light weight and they are flawed. And those speakers probably couldn't hold a linear power supply any how? There is always going to be a compromise. As long as it's not in the recording you're good and you'll only know that by listening to headphones and through other devices. It already sounds like you have tried to deal with any ground loop issues? And that didn't work. It could also be some electrostatic, electromagnetic or, RFI interference? Have you tried moving your other equipment away from the speakers like your computer? Is all of the other equipment off when you are testing the speakers for that noise with no input? Just as Boswell indicated, certain things should theoretically work but not always so in practice. Have you tried shorting the inputs to your active monitors? Or maybe even loading the inputs with a 50 ohm resistor, without any other input source?

My voice recognition software causes clocking noise since it is always scanning for input.
Mx. Remy Ann David

Hi,

thanks for your responses.

Plugging a headphone into the HP jack disables the active monitors so no more noise is audible from these.

On one of my HPs (Beyerdynamic DT 990 Pro) there is no white noise audible (250 Ohm).
But on my JH Audio 16 Pro in ear monitors the white noise it's clearly audible. The sound is very noisy on these..
Plugging them directly in the RME Babyface HP jack there is no noise audible. Dead quite.

I've also placed the monitors away form my notebook and other devices but the noise doesn't change.

There is also RFI interference on the monitors. Some GSM radio frequencies get audible when placing the iPhone
next to the speakers. (Specially when a mobile is searching for it's GSM network this is very audible, maybe I will record it..)
So it maybe it's HF interference on the active monitors that's causing the noisy sound?

btw: If I turn on an electrical device like a lamp or the TV thats also audible by a "click" sound.
Thats also a reason why I tried to fix the power source first.

The interference heard in your monitors when switching on a light or when a mobile phone transmits is unfortunately normal for many audio products and is a completely separate effect from the hiss. In a studio, it's usual to have a rule that mobile phones must be turned fully off (not just to silent) for exactly the reason that they can cause breakthrough into the audio.

The hiss you are hearing is a result of the design of the amplifiers for the monitors. If you wanted to pursue it, you would have to make some acoustic measurements with a calibrated noise meter to see whether the noise level exceeds that given in the specification of the monitors. If it does, you could take them back to the supplier with the evidence that they have a fault, and it would be up to the supplier to replace them with another pair of the same type, hoping that these have a lower acoustic noise, or else to offer a refund. If they are not significantly out of specification, you have to decide whether you can live with them as they are. If the answer is that you can't, you have only two options: a negotiated return (you would have no legal right to be offered one), or continuing your correspondence with the manufacturer in the hope that he can modify them to make them quieter or exchange them for known quieter ones. The manufacturer may in any case be concerned by the subject of alleged excessive self-noise levels from his monitors being aired in a forum like this.

Don't get me wrong :-)

These monitors are absolutely stunning. They sound great. And they're worth their price, even if they have higher self-noise level than others, I must say that I've never listened to speakers which sound that good. There is no reason why I should think about refunding or returning them to the supplier.

But it would be nice for me if they would have a lower self-noise level. In a distance of 1 to 1.5 meters the noise is not audible anymore, so the most people will never face this noise problem anyway.

So I think the manufacturer doesn't need to be concerned in any way since my use case seems to be a special case - sitting 40cm in front of them maybe isn't the best idea ;)

You cannot hear the noise through the sound, while music playback by the way...
I would recommend these speakers for sure :)

But... for my special case... the noise is a little bit irritating when not playing sound at all.
And that's why I started this thread because I didn't know if there's a chance to reduce the noise.

Hi, krymel2k10 and all of you,
I have this Munro150System and agree with you: "These monitors are absolutely stunning. They sound great. And they're worth their price, even if..." Even if!
My working distance from speakers are 1 meter and I'm not have your issue about noise and clicks, but I wonder If you have another issue with a big thump noise on power-off the system. My system have the s/n EGGME00351 and if you don't have this symptom on power-off I'd like to know your serial for reference on other faulty apparatus. They told me, sE Electronics guys, this is a "feature" on all systems that don't hurt the speakers... Well, we have 5 years warranty to see it...
Best regards,
CapB

CapBrandoa, post: 390671 wrote: Hi, krymel2k10 and all of you,
I have this Munro150System and agree with you: "These monitors are absolutely stunning. They sound great. And they're worth their price, even if..." Even if!
My working distance from speakers are 1 meter and I'm not have your issue about noise and clicks, but I wonder If you have another issue with a big thump noise on power-off the system. My system have the s/n EGGME00351 and if you don't have this symptom on power-off I'd like to know your serial for reference on other faulty apparatus. They told me, sE Electronics guys, this is a "feature" on all systems that don't hurt the speakers... Well, we have 5 years warranty to see it...
Best regards,
CapB

Hi CapB,

I also had this big thump sound on power-off. There's a simple workaround for that which I found while experimenting: Just set the -10/+4db switch below the AUX inputs from the default +4db to -10db. This thump sound will disappear immediately, but the input volume level needs to be set a little bit higher. You can also play with the bass frequency left/right controls (using a skrew driver) a little bit.

Hope you have lot's of fun with the Egg's. They are so great!

I'm also very interested in any experiences about which devices (input) are best to feed the Egg's with. I'm currently using a Macbook Pro -> RME Babyface -> Teufel Analog Amp -> Egg System for just listening music (extremely clear, transparent, 3D-like, dynamic) - really crazy good sound. For studio usage I'm disconnecting the Teufel Amp and get a neutral frequency response. Also great.

(btw. RME Babyface's hardware is equal to the recent RME Fireface interfaces.)

Best regards and happy weekend,
- Aron

Ah and: I wonder if you can hear the noise sound (without any sound playback) in 40cm distance to the speakers. (Just turning them on and listening to the white noise?)? Thanks!

Hi krymel,

Thanks for your prompt reply. Yes, I can hear a very low level DC (I think) noise at that distance but my environement is sufficient noisy to cover that (not that much but still enough ;).
I have noted that with headphones inserted and the volume down, the speakers don't receive the thump pulse, which I can hear open the volume a bit. I'll use this workaround instead
of -10/+4 trick to protect the speakers. Do you know if the rear trimpots are in the flat condition when fully clockwork side or in the middle detent point?

About the interfaces, I use digidesign 003R (with pro tools 9) in musical work (I play guitar and do some music produce work). My previous monitors was Dynaudio BM6A which I sell to buy this another Munro design, that I have waiting for near two years since I have read about in a magazine. Like you, I love this system and hope sE improve the amp issues in the future (I think there are more to show up).
Best regards and good work,
CapB

Hey everyone,

I see this is an old thread, though I'm curious about what was the outcome with Andy Munro?

I have what appears to be an early serial number pair of sE Munro 150 EGGs (EGGMA00123) and have the low buzzing issue. It also easily picks up GSM phone signals. The buzz is stronger in the left than the right. At some stage but not in the next year or so I'll drive them from a better four channels of amp and a DSP loudspeaker calibration device like the Trinnov Optimizer, but in the meantime I'd like to get the best from what I've paid for and the EGG amp unit.

Otherwise yes awesome speakers.

I'm quite sure the amp uses an older style linear power supply with a toroidal transformer, referring to what the banned member RemyRAD wrote.

Thanks for any help guys,

Nick