8800NL - high pitched noise

[jrawle]

I have just bought a 8800NL to replace my BT Hub 3/Openreach modem. I had previously tried a Hub 5, but didn't like it for a lot of reasons, mainly that it made a continuous clicking noise, and buzzed on wifi access.

Before choosing a new modem, I asked owners on Amazon whether various models made any noise, and was told the 8800NL is silent.

Now I have one, it doesn't make the clicking sounds the HH5 did. However, it does emit a high-pitched whistle continuously when it is on. This seems to start once it is connected to VDSL, and then is heard continuously. It is very high pitched. If I rest my phone on top, bs-spectrum shows a spike at 8 kHz.

Admittedly, I have pretty good hearing. I also like to have a quiet environment to stream music (mainly classical) to my hifi. This sort of high frequency noise is very annoying, as it comes in and out of hearing as I turn my head or move about the room.

What I would like to know is whether this is simply a "feature" of the 8800NL, or whether I have a faulty unit. I actually ordered a second unit to try, but it was the same. The only other thing to try would be a different supplier in case they are bad batch. Please could people have a listen (you might need to put your ear right up to the modem in a noisier environment)? I find you can hear it more loudly from behind the modem. But again, I do appreciate that many people will not be able to hear the sound anyway. You could also try measuring it using a phone app (I use bs-spectrum free for Android).

I like the modem in every other respect. It has the features I require, and has low power consumption, running fairly cool (unlike rival models). If I can't get one that runs silently, I'll have to try re-siting it where it's more our of earshot (within the constraints of cables, tidiness, etc.) or even putting it inside a cupboard (at least it is fairly cool-running, but even so, I'm reluctant to do this).

Any comments/input would be appreciated.

[billion_fan]

I have just bought a 8800NL to replace my BT Hub 3/Openreach modem. I had previously tried a Hub 5, but didn't like it for a lot of reasons, mainly that it made a continuous clicking noise, and buzzed on wifi access.

Before choosing a new modem, I asked owners on Amazon whether various models made any noise, and was told the 8800NL is silent.

Now I have one, it doesn't make the clicking sounds the HH5 did. However, it does emit a high-pitched whistle continuously when it is on. This seems to start once it is connected to VDSL, and then is heard continuously. It is very high pitched. If I rest my phone on top, bs-spectrum shows a spike at 8 kHz.

Admittedly, I have pretty good hearing. I also like to have a quiet environment to stream music (mainly classical) to my hifi. This sort of high frequency noise is very annoying, as it comes in and out of hearing as I turn my head or move about the room.

What I would like to know is whether this is simply a "feature" of the 8800NL, or whether I have a faulty unit. I actually ordered a second unit to try, but it was the same. The only other thing to try would be a different supplier in case they are bad batch. Please could people have a listen (you might need to put your ear right up to the modem in a noisier environment)? I find you can hear it more loudly from behind the modem. But again, I do appreciate that many people will not be able to hear the sound anyway. You could also try measuring it using a phone app (I use bs-spectrum free for Android).

I like the modem in every other respect. It has the features I require, and has low power consumption, running fairly cool (unlike rival models). If I can't get one that runs silently, I'll have to try re-siting it where it's more our of earshot (within the constraints of cables, tidiness, etc.) or even putting it inside a cupboard (at least it is fairly cool-running, but even so, I'm reluctant to do this).

Any comments/input would be appreciated.

I'm not aware of the high pitch noise emitting from my test 8800NL (like you said most people won't hear it), if you have two devices that are same, I think its more of the normal operating noise.

Others can comment, as there are plenty of 8800NL users here on the forum

[gatekeeper]

jrawle,

I empathise with your noise problem. Not because I experience it myself but because, like you, I've sensitive hearing and find that any noise of that sort not only irritating and spoiling of any audio recordings I make in the same room, but also tiring in the longterm. Indeed, prolonged exposure could lead to tinnitus. I've spent many years and a lot of time, effort and money on my own computing setup to keep 'machine noise' as low as possible.

In my view, a router or modem should be that and that alone, not an audible noise-emitter or anything else that could damage your health. You could argue, therefore, that the router-modem in this instance isn't fit for purpose, under UK law (that's assuming of course that it and the second one are from a rogue batch). Frankly, if I had your problem right now, it'd drive me completely nuts!

I'm currently using my 8800NL in ADSL mode and that's why I'm not hearing any noises coming from it; I've not had it in VDSL mode but I may, quite soon, be shifting to an FTTC account with my ISP, so your unfortunate experience is of interest.

I think that one of the things that you and I are up against is that, these days, the vast majority of people have lost the ability to listen properly; instead, everything these days is geared toward things visual; the subtleties of high-quality listening are lost on most people, especially when audio content is so often played at loud volume. This means you'll probably be hard-pressed to find someone sufficiently discriminating to give you a worthwhile opinion on whether they think the noise is there or not.

Is the noise actually coming from the 8800NL itself, or instead from its power-supply brick? It might be that some sort of HF resonance is occurring, most likely in an inductance coil inside the unit. There may well be a number of such miniature coils on the 8800's circuitboard that are used to filter any electrical noise that's picked up - including any DC ripple that might come from the external power-brick - or which may be part of one or more onboard timing circuits, or associated with the wireless transmit/receive circuitry. It might be that additional current drawn by the unit in VDSL mode then causes the coil(s) to mechanically resonate and the result become audible. I've had this sort of thing happen in other, totally different kinds of digital equipments, including some top-of-the-range and highly expensive devices, and I can assure other readers of this thread that it can be highly irritating. Sometimes, standing waves can be set up in the room, with peaks and troughs occurring in certain spots. The manufacturer's laboratory may not necessarily be the best place to test for things like this.

Mechanical resonance of this kind isn't well understood these days but in some cases I've known equipment designers/manufacturers encase the offending components in hard wax on the circuitboard, to quench the noise.

BTW, did you acquire the two 8800's brand new? And from a reputable retailer? You didn't buy the 8800s at a knockdown price, by any chance, did you?

Is there perhaps a more beefy power-brick to hand that you could use with the unit, to see if that makes any difference to the perceived noise when in VDSL mode? It might be the extra strain on the power-brick in VDSL mode that then causes the mechanical resonance in the unit. You'd need to use one with the same average output voltage and same voltage polarity, but with a higher current rating. Usually, power-bricks, which normally contain only a small transformer, a block rectifier, and if you're lucky a small smoothing capacitor, have a label with all of that written on. Regulation of the DC voltage is usually performed on the unit's circuitboard.

Incidentally, do you still get the same noise if you switch off the wi-fi connectivity and use Ethernet cable(s) instead?

Another thought is whether you're in a position to be able to try the 8800 on someone else's line - just in case there's a fault on your own line which is causing more current than normal to be drawn by the 8800.

I've been wondering whether to replace my 8800NL with a Billion 8900AX-2400, if and when I swap to FTTC, and so, considering the exceptionally high cost of the 8900AX-2400 model, I'd be extremely annoyed indeed - and probably put off Billion routers/modems for good - if I found that it emitted a continuous audible tone!!!!

[gatekeeper]

Just had another thought. When you tried with a second 8800, was that second one a replacement, or was it literally a further one? What I'm thinking is whether you tested the second 8800 with the original one's power-brick. If so, try the power-brick that came with the second one - just in case there was something amiss with the first power-brick.

Let me know how you get on in trying to sort this out.

Of course, it'd help enormously if other 8800 owners using VDSL mode were to have a quick listen, right up against the unit, and report their findings in this thread. It'd not be asking much, would it? So, go on, all you 8800 VDSL users - listen!

[jrawle]

Thanks for the replies, gatekeeper, which I only saw today.

The noise is definitely from the modem itself. The power supply lets out a "chirp" when the modem is first powered up, but it then essentially silent. You are correct that I tried both units with the same power supply. This was to avoid undoing all the cables in the second box so as to make the return under the Consumer Contract Regulations smoother. While I agree the fair test would be to use a different supply, I strongly suspect this is not the cause. The modems are silent until they connect to VDSL, after which they emit the noise. I can't see that this could be due to the power supply, although as you say it's not possible to know if there is some sort of strange resonance.

Switching off wifi has no effect.

The usual supplier I use said the modem was "discontinued", so I quickly bought from a retailer I haven't used before, but which seems genuine. Ironically, my favourite supplier then found more stock, which was again exhausted by the time I decided to try a second one, which was frustrating as I would have liked to try a different batch.

I'm not doing any more tests, however. I need to maintain a lengthy uptime in order to reset the DLM capping that Openreach has applied to my line. My old Openreach modem or Hub 3 was evidently faulty, and was dropping the connection at least once each evening. As a result, my speed was down, so I don't want to disconnect to try different things until my speed is restored.

I now have the modem in its proper place on a shelf under my desk, having bought a longer RJ11 cable. I think it is slightly more slielded there than out in the open. In actual everyday use, any sound is masked by the sound of my PC, music (if it's not too quiet) and the fridge in the kitchen next door. I can still hear the noise if it's quiet in the room, late at night. I doubt consumer law would get anywhere, as the supplier would claim it does what is advertised, and no acoustic specifications are given. Also, I could have returned it under the Consumer Contract Regulations if I was unhappy. The trouble is, there is no other device on the market that fits the bill. Apart from this issue, I am happy with the 8800NL, the connection's been rock steady so far. Let's hope it sorts out my DLM issue!

[gatekeeper]

"The power supply lets out a chirp when the modem is first powered up ....".

Really? What would be the purpose of that? I'd think it very unlikely indeed that such a crudely-designed power brick would ever include any sort of purpose-designed electro-acoustic emitter, especially as it sounds only the once, according to you. I myself have never ever heard of the power-brick chirping, and believe me, I'd notice that!

I think I'm correct in saying that the power-brick merely develops a crude 12v or so DC, for then passing to the 8800, with the main smoothing and regulation of that DC voltage being performed in the 8800 itself; the power brick contains little more than a small transformer, a rectifier stack, and possibly a preliminary smoothing capacitor; in some power bricks used with modems, an ac (rather than a dc) voltage is passed from the brick to the modem, leaving all of the rectification, regulation and smoothing to components contained within the modem, this tending though to cause more heat to be generated within the modem. Some rectifier stacks, especially the small plastic, encapsulated ones, designed to handle only an amp or two, can be especially prone to partial damage by mains-supply spikes.

I'd hazard a guess that the issue you're experiencing is down to some hardware problem with the power brick, which is then causing a detrimental effect in the modem unit itself (maybe some sort of HF ripple component finding its way on to the incoming/outgoing VDSL sync signal). I do very vaguely recall hearing about a power-brick issue with the 8800NL when that model first became available in the UK and indeed, in ordering an 8800 for myself many months ago now, I half expected to have to swap its supplied power brick for a better, more beefy one. But that didn't prove necessary.

Other 8800 users that I've managed to contact in the meantime about this say that all they hear is silence and that if you're hearing a HF noise it's most likely the power-brick that's the cause of that. There was only one case cited of an acoustic issue and that definitely involved the power-brick. The individual concerned fixed the matter by opening up the brick (I thought they were sealed units!) and applying some glue to a badly-mounted component.

Let us know if in due course you have any success in pinning down more accurately the source of your problem. It might be that the retailer from whom you've bought the two 8800s have sold you either old stock or 8800s that were returned by their original purchasers, the power-bricks having been internally damaged. It might be worth you checking that the power-bricks you've obtained are absolutely identical and are the official ones normally supplied with the 8800. If you've a beefier power-brick kicking around that you know is good (check that its output is roughly the same and is of the same polarity), try that in place of the ones supplied with the two 8800s.

Electro-mechanical resonance within the 8800 unit itself isn't beyond the bounds of possibility, though, and I've already mentioned that. One of the contacts I made pointed out that not long ago PlusNet, here in the UK, had a problem of that kind with the in-house ADSL routers that they supplied to their end users. Many of them had to be returned to PlusNet. It was some sort of production-quality issue but it's not clear as to precisely what was at fault. My guess is that it was down to a circuitboard-mounted coil mechanically resonating due to poor mounting.

[pintosal]

My 8800NL is silent, as is the power supply.

That does not help you, I'm afraid, except in so far as they are not all noisy.

[gatekeeper]

Thanks for letting us know, pintosal. I assume you're using your 8800NL in VDSL mode.

[pintosal]

Yes, that's correct.

[jrawle]

My 8800NL is silent, as is the power supply.

That does not help you, I'm afraid, except in so far as they are not all noisy.

Are you certain that you would be able to hear the high frequency sound I am referring to? Not wishing to appear rude, but I had a similar (but completely unrelated) problem at work with a high pitched noise, and found most people simply could not hear it.