AC511 USB Soundbar, static

The windows sound volume should be set to no higher than 50%. I understand that the manual says to set them to maximum but that overdrives the speakers.

Same problem here. Just took receipt of an AC511 yesterday. Sound quality is great when audio is played, but when not in use, the buzzing is driving me crazy. Volume controls do nothing, nor does the choice of USB port. Any idea if this is a bad batch or is it a basic flaw of the design?

Hi Chris,

The sensitivity of the volume control is a minor problem, although it makes it impossible to play at a really low volume.

The major problem is the static noise that is constantly on, independent of volume setting. Could you please try to find some demo units in the Dell office and see if they exhibit the same problem? You won't notice anything in a noisy environment but as soon as it gets quiet around you will hear the hissing.

FYI: the noise will come on as soon as the USB Audio device gets initialized in Windows so normally you don't have to configure anything, just plug into any computer. Note though that if you plug into a charger USB (only providing power) the unit will power up but will be totally silent, so it seems the noise has to do with the USB Audio adapter and not the amplifier circuitry. Maybe upgrade flash to fix?

Best regards
Mike

There will not be a firmware update for this. All you can do is contact Dell Order Support and get a like for like exchange. The AC511 has a one year warranty starting from the Dell invoice date.

Thanks Chris,

There have been other reports of exchanges coming back with the same hissing problem.

Could you please check with your product specialists or look up demo units to see if this affects all units? It just wastes resources and everybody's time doing exchanges if it's not possible to find units without the hiss. Better to get the honest facts and act according to that. We all know that sometimes product design goes wrong.

Best regards
Mike

I have emailed the Displays team.

There is not a systemic fault with the AC511 and we do not consider this a flaw. The noise was present but well below the Dell parameters dictated to the manufacturer for this $29.99 speaker. Inside the first 30 days from the Dell invoice date, you may contact Customer Service and return it for refund.

Thanks for getting back to us Chris,

So was the sound you experienced similar to what I recorded in the video of my first post?

Wrt sound level the experience with my unit is that it is fair to say you will not notice the speaker buzz if you have a somewhat noisy computer, but will if you have a quiet system and surroundings. Does this description match what you saw?

It would be interesting to know the limits/parameters Dell sets up for this kind of ambient noise from an idle speaker? (X dB at Y distance)

If I come across a dB meter I can check if my unit deviates. If it doesn't, I think it would be good if you could pass on the message to the "parameters folks" that customers expect lower noise characteristics than currently specified. I wouldn't expect the "you get what you pay for" argument as the AC511 is the only compatible soundbar for my monitor and no higher-end alternative is offered.

Best regards
Mike

Hi,

I just received my replacement AC511 soundbar from Amazon. The first I returned as a result of the buzzing/static issue, as described by Mike. 

Sadly, the replacement produces the exact same issue. constant low level buzzing/noise, not affected by the volume controls. I have tried several different PCs, all of which produce the same result. As Mike mentioned in a previous post, plugging it into a USB wall charger initializes the speakers with no noise whatsoever.

I can only surmise from this, that this is an issue with the fundamental design of the speaker, rather than a specific manufacturing fault. Something as simple as an On/Off switch would at least have allowed you to turn off the speaker when not in use, rather than having to put up with the constant buzzing.

I know it's not exactly expensive and I wasn't expecting reference level sound quality (actually the sound quality when something is actually playing exceeded my expectations. It's very good in that respect), but I can't believe that the cost some electrical shielding around the areas sensitive to noise/static would have been anything more than negligible. I have some HP USB speakers that cost £10 that do not exhibit this issue, so it can be done.

Anyway, sadly the soundbar is going back for a refund. It's a real shame. The integration with the monitor is great and, as I mentioned the sound quality when actually playing something is very good considering the price, but I can't live with the constant buzzing noise. If ever an AC511 Mk2 is released, which resolves this issue, I will bite your arm off for it! 

Many Thanks,

Ross.

Buzzing like this is many times caused by a “ground loop”, resulting from improper grounding in the unit. Apparently this is a fault in the design.

Kirk, a ground loop makes me think of a 50 or 60 Hz buzz leaking in from the power supply. My AC511 is emitting a wide-spectrum noise, closest to grey noise from the alternatives you can play here:

http://en.wikipedia.org/wiki/Colors_of_noise

BTW, the same noise appears when connecting to a laptop running on batteries.

Ground loops can occur in DC circuits. All it needs is two supposedly connected parts not being at the same voltage, because of unwanted resistance in a connection. Also, with audio, you are working with AC signals. We had a problem with noise in a video projector connected to an auditorium sound system. It didn't sound like typical 60 hz "hum"; no noise with microphones on the same input. The tech said it was a ground loop, but I don't know the details,

Hi all,

I work for a School district and am experiencing the same issue with the AC511 USB Soundbar. We have several units across the district with this issue AND an additional issue with a loud static noise when locking and unlocking the computer. The fact you are telling users you have duplicated the issue and, though it is driving people crazy, that it is NOT a flaw. It is a flaw. Also telling users to only use the soundbar at 50% volume is an insult.

Optiplex 3020 and 7020. Windows 7 x64 Enterprise
Driver version: 6.1.7601.18208
Date: 7/12/2013

I totally agree about the price point argument. And as I stated earlier, the AC511 is the only compatible soundbar on offer for my monitor.

BTW, in Sweden where I am located the soundbar was $60 incl shipping at the time, which I do not consider dirt cheap. And depending on your buyer/channel profile you might not have a money-back guarantee either.

I'm having the exact same problem with the AC511. The hissing noise makes the speaker unusable. Clearly, these speakers are flawed and Dell should provide a fix or replacement.