Anyone else's Neumann KH80 randomly reset themselves?

[Hugh Robjohns]

... digital attenuation results in a loss of bit-depth and possible dithering artifacts, but running your signal through the analog inputs means a D>A>D>A>D>A signal path when used with the KH 80s...and that is a LOT of conversion. Any thoughts on this would be welcome.

Back in the late 90s I ran a signal through 50 D>A>D passes using Sony pro DAT machines (44.1/16 bit) and then asked countless BBC soundies to identify when they were aware of degradation. A few felt they could start to hear artefacts after ten generations, but most struggled to hear any difference until closer to 20 passes. And that was over twenty years ago... Converters are even better these days.

So I wouldn't be too worried about quality going through multiple converters.. The latency might be more of an issue, depending on how you're using the monitors.

But actually, digital attention isn't a problem. If you have dithering artefacts then the attenuator coding is broken. And a 'loss of bit-depth' is a total red herring. The wordlength defines the signal-to-noise ratio. Nothing more. Attenuating the signal level reduces the signal-to-noise ratio... Exactly as it does in an analogue system. And with 24-bit converters the digital system noise floor will be no worse than n blogger system's noise floor.

So again, it's not something I'd lose any sleep over.

Thanks for the suggestions about resetting the KH80s. I'm sure many owners will find that useful.

[adambier]

But actually, digital attention isn't a problem. If you have dithering artefacts then the attenuator coding is broken. And a 'loss of bit-depth' is a total red herring. The wordlength defines the signal-to-noise ratio. Nothing more. Attenuating the signal level reduces the signal-to-noise ratio... Exactly as it does in an analogue system. And with 24-bit converters the digital system noise floor will be no worse than n blogger system's noise floor.

Thanks, that's very helpful, Hugh. I wondered whether that was the case (since you're effectively only discarding unused bits), but I've seen so many different folks on various forums with all kinds of theories about this I wasn't sure.

The bigger issue with connecting monitors via a digital connection is that most interfaces just pass the bitstream through, without applying any attenuation via the control knob, but in a multi-purpose setup, the convenience (and safety, as a panic control, if there's an unexpected loud signal from the computer) is hard to give up. I'm curious if others have come up with workarounds.

[Mike Shand]

1) I spoke with the speakers product portfolio manager at Neumann Berlin. False positives (waking in the absence of a signal) are always going to be a bit of an issue on the KH 80 DSPs, since they don't have a third ground prong, which means they're more subject to line noise

Thank you for a very informative and useful post. I struggled with these problems and tried everything before finally giving up and switching them on and off manually.

[air2k]

Increasing the standby threshold to something high (max is 30 dB SPL @ 1m) will help,

Is this really true? My observation/tests showed no influcence of the standby level and the frequency of sporadic wakeups.
Additionaly, I could not find an hints in the manual/faq that the standby level is indeed connected to the wakeup level.
My guess is that the standby trigger is done in software (therefore configurable), while the wakeup-trigger is fixed in analogue circuits (therefore not configurable), as the manual mentions that during standby, almost all subsystems are unpowered.

To remove other network traffic as a possible cause of problems, I recommend buying a $50 wifi router with at least 2 ethernet jacks on the back (or use an old one you have lying around). Do NOT connect the router to the internet or the rest of your network and just connect your two monitors to the router via ethernet and connect your iPad to this isolated network via wifi.

Software engineer here. This statement is just wrong. Don't invest any time/money to do 'network isolation'.
I reverse engineered the network protocol (OSC based, BTW) between the neumann.control app and the KH 80 and random interference from other devices on the same network is impossible as long as they don't expecitly target for the IP addresses of the KH 80 and know how to speak with them.
BTW, I managed to control every parameter from my desktop machine without using the app as a proof of concept. If my free time would allow it, I would try to publish a free tool which can replace the ipad app.

[Hugh Robjohns]

You would certainly win a lot of friends if you came up with a usable mac/win desktop app to control kH80s!

[adambier]

Grrr, I'm sorry to report that after 1-2 weeks of problem-free operation (having gone through the protracted process described in my earlier post), a couple days ago I had two apparently random power cycles (which look to be standby while a strong signal is present, followed by a pause, and then the monitors waking up again--OTOH, it could be an unrelated reboot, but no way to be sure).

The first such incident involved only one of the monitors, but the second involved both, about 8 seconds apart.

I'm 95% sure this only happens when auto-standby is enabled (and do not have enough data to say whether this only affects things when both auto-standby and network-control are enabled, or whether auto-standby plus local-control also results in this issue, though anecdotally I suspect it's the former).

Without some kind of logging functionality, I'm at a loss for how to diagnose things further (apart from giving up and manually powering them off and on, or just leaving them on all the time).

The only other thing the folks from Sennheiser mentioned was potential mains power issues--I'm not totally clear one what exactly those would be, but I don't really want to buy a bulky online UPS just to ensure perfect sine waves and exactly 120V as an experiment.

Increasing the standby threshold to something high (max is 30 dB SPL @ 1m) will help,

My guess is that the standby trigger is done in software (therefore configurable), while the wakeup-trigger is fixed in analogue circuits (therefore not configurable), as the manual mentions that during standby, almost all subsystems are unpowered.

That's certainly possible, though a weird design decision given that the DSP and other DC circuitry probably use a tiny amount of power compared to the amp(s).

To remove other network traffic as a possible cause of problems, I recommend buying a $50 wifi router with at least 2 ethernet jacks on the back (or use an old one you have lying around). Do NOT connect the router to the internet or the rest of your network and just connect your two monitors to the router via ethernet and connect your iPad to this isolated network via wifi.

Software engineer here. This statement is just wrong. Don't invest any time/money to do 'network isolation'.

I reverse engineered the network protocol (OSC based, BTW) between the neumann.control app and the KH 80 and random interference from other devices on the same network is impossible as long as they don't expecitly target for the IP addresses of the KH 80 and know how to speak with them.

Definitely not a software engineer here, but, dunno, multicast issues?

Apart from comments from the Sennheiser rep that one should eliminate network issues as part of troubleshooting, my main concern was eliminating errant commands from the Neumann.Control app. Isolating the network doesn't technically affect that, but it does allow me to switch the iPad to the normal house WLAN immediately after pushing out the configuration, limiting the exposure during the period between that and physically disconnecting the monitors from the isolated network.

BTW, I managed to control every parameter from my desktop machine without using the app as a proof of concept. If my free time would allow it, I would try to publish a free tool which can replace the ipad app.

That would certainly be great. It's disappointing that the desktop software for use with the new MA-1 doesn't support System-level configuration, including standby settings or gain control. Neumann is obviously not primarily a software company, but this seems half-baked.

I really, really want to be happy with these monitors. I think they sound great. This is arguably a silly issue, but it's frustrating.

Any other thoughts (or potential solutions) are certainly most welcome.

[air2k]

The only other thing the folks from Sennheiser mentioned was potential mains power issues--I'm not totally clear one what exactly those would be, but I don't really want to buy a bulky online UPS just to ensure perfect sine waves and exactly 120V as an experiment.

I invested hours of testing after setting standby time to 1 minute:

At first, I measured my balanced outputs to the KH 80 for signal spikes (by using an audio interface connected to my high quality USB audio interface outs) but I was not able to measure them (looking at peak SNR) therefore I would rather rule this out as a cause.

1) KH 80 not connected to any signal source (leaving the XLR cables unconnected).
Ethernet cables are connected.
-> no sporadic wakeups (tested for 30 minutes)

2) KH 80 connected to an USB-powered Audio interface (without any signal, setting output level knob set to zero) with ground lift enabled on the interface.

a) Ethernet cables are connected.
-> sporadic wakeups on rather both KH 80 (after ~2 minutes), but they do not go into sleep reliably

b) Ethernet cables are disconnected
-> significant humming audible

3) KH 80 connected to an USB-powered Audio interface (without any signal, setting output level knob set to zero) with ground lift disabled on the interface

a) Ethernet cables are connected
-> sporadic, more random wakeups (first wakeup after ~5 minutes),
happens much more likely on one of the two KH 80 (even if I switch the audio channels), but usually sleeps again after 1 minute.

b) Ethernet cables are disconnected.
-> sporadic, less likely (compared to 2a) random wakeups (first wakeup after ~20 minutes),
happens much more likely on one of the two KH 80 (even if I switch the audio channels), but usually sleeps again after 1 minute.

4) KH 80 connected to via an active, battery-powered DI box (ground-lift disabled). The Di box is connected to an USB-powered Audio interface (without any signal, output level knob set to zero)
-> sporadic wakeups on rather both KH 80 (after ~3 minutes)
This also happens if I set a 20db or 40db attenuation at the DI box.
This is another hint that the problem has nothing to do with the signal lines (e.g. spikes, SNR etc.)

5) KH 80 connected to via an active, battery-powered DI box (ground-lift enabled). The Di box is connected to an USB-powered Audio interface (without any signal, output level knob set to zero)
-> extremely loud ground-loop-like-humming-noise (not present when ethernet cable IS connected). Hopefully the oberload protection at KH 80 worked. I'm sure my neighbors just woke up
Not sure if this originates from my rather cheap DI box or from an issue within the KH 80.

Taking the results of above tests and obvervations into account, especially the influence of a connected ethernet cable (connecting an ethernet cable will also likely cause the KH 80 to wake up!) I suspect grounding (earthing) issues with the KH 80's wakeup/standby functionality as the most likely cause (eventually because they only have a 2-pins main connection, so the grounding reference is missing).

This would also explain the randomness as well as the strong dependency on the actual setup/electrical environment.

To everyone affected: Remove your ethernet cables (if present) and see if this reduces unwanted wakeup/standup probabillity.

Definitely not a software engineer here, but, dunno, multicast issues?

Multicast is only used for device discovery (via mDNS). Actual communication to the KH 80 happens via regular (unicast) TCP connections.

[air2k]

I did further testing. Standby time still set to 1 minutes.

This time, I connected both KH 80 to an analog mixing console with the master fader set to the lowest output level - which means that it doesn't output anything at all)

Beside the mixer's 3-pin main power connection and the balanced connection to the KH 80, no other signal has been plugged in. Ethernet cables are not connected to the KH 80.

The KH 80 wake up in this set up as well. A little bit less often (~15 minutes) compared to my USB audio interface. And still conspicuous and similar to my previous tests: One of the KH 80 woke up much more often than the other (also when I swapped inputs).

This brings me to the conclusion:
* the KH 80 most likely have a serious engineering flaw regarding standby/wakeup functionality.
* there is a significant manufactoring variance which has an influence of the occurence probabilty (my 2nd KH 80 showed the issue 10 times less).

[Drew Stephenson]

Appropos of nothing one of mine just switched itself off mid-playback this arvo. And didn't come back on automatically, had to go round the back and switch off and on.

[Mike Shand]

Is this really true? My observation/tests showed no influcence of the standby level and the frequency of sporadic wakeups.

I certainly found the standby level had no apparent influence on frequency of wake ups.

[air2k]

Appropos of nothing one of mine just switched itself off mid-playback this arvo. And didn't come back on automatically, had to go round the back and switch off and on.

Although Auto-Standby is enabled? That's strange.

However, I turn Auto-Standby off, then I have the same behavior - but then the KH80 are always-on which I'd like to avoid (but didn't reboot/poweroff so far).

[Drew Stephenson]

Appropos of nothing one of mine just switched itself off mid-playback this arvo. And didn't come back on automatically, had to go round the back and switch off and on.

Although Auto-Standby is enabled? That's strange.

Yes, first time it's failed to re-awaken, only the second time it's gone to sleep mid play.
If it becomes more regular i'll just switch off the auto-standby.

[Drew Stephenson]

Just a quick update to say that they've started turning off whilst playing more frequently so auto-standby has gone off.

[Hugh Robjohns]

I have to say I am so disappointed with the whole KH80 auto-power saga. It's the kind of thing that is almost impossible to detect in a typical review period, and I'm glad users are reporting the issues here (and elsewhere) -- but they should all really be bombarding Neumann with complaints about this as it's clearly not a design that's fit for purpose. A proper solution is required.

Thankfully, it doesn't affect the speaker's core usability and it remains, of course, a superb sounding monitor speaker, but it does cast a nasty shadow both on the speaker and the manufacturer IMHO.

[Drew Stephenson]

Yes, for me it's not really a black mark, more of a smudge. I still have a really nice sounding set of monitors, I just have the first-world-problem of having to manually turn them off.

[Hugh Robjohns]

Quite.

Neumann presumably added the auto-power mode to comply with the EU green energy requirements, but the poor circuitry implementation means the function won't actually be used and it has downgraded the appeal of the speaker for many to boot! Double whammy...

[adambier]

Quite.

Neumann presumably added the auto-power mode to comply with the EU green energy requirements, but the poor circuitry implementation means the function won't actually be used and it has downgraded the appeal of the speaker for many to boot! Double whammy...

I think that conclusion is inescapable, unfortunately. I ultimately gave up trying to get standby to work on the KH 80s and instead bought one of these (which is a U.S. version but I'm sure there are similar things in the UK and EU):

https://www.amazon.com/gp/product/B005R2UFUG/

My KH 750 sub is connected to the control socket and the KH 80s are set to always-on and connected to the relay sockets.

The KH 750 both has marginally better signal-detection circuitry (probably because there's a third ground) and I'm currently connecting to it via an SPDIF connection, which is even more binary in terms of on or off state.

Note that in order for that approach to work, your interface or other digital source has to either connect via coax or your TOSLINK-to-coax converter has to be smart enough to disconnect voltage from the coax output when no valid audio signal is present on the optical input; many cheap boxes on Amazon will continue to pass ones and zeros over the copper wire anytime the photoelectric sensor is receiving light of any kind.

This item works about 80% of the time (with false wakes maybe 2-3 times a day):

https://www.amazon.com/gp/product/B084T4QDFP/

I've also ordered one of these, which is supposed to be much smarter:

https://www.tindie.com/products/beni_sk ... io-switch/

[Kayvon]

I have to say I am so disappointed with the whole KH80 auto-power saga. It's the kind of thing that is almost impossible to detect in a typical review period, and I'm glad users are reporting the issues here (and elsewhere) -- but they should all really be bombarding Neumann with complaints about this as it's clearly not a design that's fit for purpose. A proper solution is required.

Thankfully, it doesn't affect the speaker's core usability and it remains, of course, a superb sounding monitor speaker, but it does cast a nasty shadow both on the speaker and the manufacturer IMHO.

It would be nice to have some official word at least.

I guess I always coped before (energy bill wise and just the thought that something was sitting there imbibing the Earth's resources) but having had and being reassured by the feature it's bothersome to have to bypass it.

Oh well, i guess in the grand scheme of things it's not even a drop in the ocean in comparison to the energy and resources we will devour over the course of our lifetimes.

It's like a small pout in the right direction and generations to come will collectively and helplessly add to the waste to an obscenely damaging degree before we can learn be respectful and mindful enough to sustain ourselves on this planet without mashing it up.

Makes you wonder about that next vintage remake at the low low.

[melodnb]

I was driven here by word of mouth that someone had found a way to bypass the stupid DSP control requirements of an ipad or the ma-1 mic. Mr. air2k I would pay you to simply develop an app that lets me disable the LED logo. These things are blinding.

[MarkBerlin]

Hi, I asked Google why my new Neumann KH80 DSP speaker randomly switches off (and on) while the music is playing and Google led me to this thread.

Random switching off (and on again) happens only on the one of the two speakers, at listening levels (not too hot, but definitely not so quiet that auto stand-by function should kick-in).

So, I guess there must be something to it. It's sounds like the very same issue that OP and some others have described.

My KH80 DSP speakers are made in Czech Republic, btw (not Ireland). Maybe the change in the production site also brought some QC issues?

How do you guys go about contacting Neumann/Sennheiser and filing a complaint?

@Neumann/Sennheiser - are you listening? Help!

Best, Mark

[Hugh Robjohns]

How do you guys go about contacting Neumann/Sennheiser and filing a complaint?

Start by contacting your local distributor:

https://en-de.neumann.com/distributors

[Bob Bickerton]

Without reading the entirety of the thread.... if the problem is the auto standby function just switch it off! I'm not inclined to use it anyway. Either I'm using the speakers or I'm not, so they're either switched on or they're not - there's no need for such trickery - especially if it's malfunctioning.

Bob

[Hugh Robjohns]

That is, of course, the obvious pragmatic solution, Bob. But for some purchasers the auto power feature was a key element of their buying decision, and I think a manufacturer should be held to account when so many are apparently having the same problem.

[Bob Bickerton]

Fair enough.

Bob