Powered speakers hum or buzz because of several possible problems in the audio chain: a ground loop, a faulty or unsuitable cable, an unbalanced connection, electrical interference, or an issue with the speaker or source. The quickest way to narrow it down is to turn the speaker level down, disconnect its signal inputs, then reconnect devices one at a time. Never remove or defeat the speaker’s protective mains earth.
What the noise can tell you
A steady low-frequency hum can point to a ground loop, particularly if it starts when you connect another device. Sennheiser describes hum around 50/60 Hz as a common ground-loop symptom; Mackie says a 60 Hz hum that appears only when another device is connected suggests a loop. These are clues, not proof: cables, interference, unbalanced connections, and speaker or source faults can also cause noise. Sennheiser’s guide and Mackie’s SRM450 FAQ describe these symptoms.
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Note when the sound occurs before changing anything: with no audio playing, only after a particular device is connected, or when you move a control. Lower the speaker level before testing. A low level reduces the chance of an unexpected loud signal as you reconnect equipment.
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Isolate the cause one connection at a time
- Disconnect the signal inputs. Leave the speaker connected to power, but remove the audio cable or cables going into it. If the noise stops, the source, cable, or connection between devices is implicated. If it remains, the speaker or its power environment may be involved.
- Reconnect one device and cable at a time. Listen after each change and note which connection brings the noise back. This controlled approach helps distinguish a source-related problem from a cable or connection issue.
- Substitute a suitable cable. Check that connectors are secure and use a known-good, properly shielded cable intended for line-level audio. A damaged or unsuitable cable can introduce noise; avoid changing several cables and devices at once.
- Check cable routing. Keep audio signal cables away from AC power and lighting cables where practical. If moving a cable changes the noise, interference or routing may be contributing.
- Try another source, if available. If a different source works quietly through the same speaker and cable, the original source or its connection deserves attention. If the noise follows the speaker regardless of the source and cable, consult the speaker’s manual or support.
Sennheiser recommends signal-input isolation as a diagnostic step, and PreSonus also advises checking connections and audio wiring. Neumann’s steps address the KH 120II specifically; its cable and service guidance should not be read as a specification for every speaker. Neumann KH 120II troubleshooting.
#1 Best Overall
- 2 x AUX INPUT - Convenient connection to any device that has a 3.5mm headphone output or dual RCA output. Connect to two devices via AUX at the same time, no plugging and switching needed.
- STUDIO SOUND QUALITY - Natural sound reproduction from 13mm silk dome tweeter and 4 inch full range unit
- REMOTE CONTROL - Adjust volume at your figure tips. Bass and treble control located on the side of main speaker.
- CLASSIC WOOD FINISH - High quality MDF wood build finished with wood effect vinyl serves as a great compliment to any home decor.
- SIDE PANEL CONTROLS - Use the side panel knobs to adjust the EQ to your liking. The controls are located on the active/powered speaker.
Choose a fix that matches the connection
Use balanced audio when both devices support it
A balanced XLR or TRS connection can reduce susceptibility to interference when the source output and speaker input both support balanced audio. Check the manuals: a socket’s shape alone does not establish that its signal is balanced. Use the correct cable and connection type for both devices.
Consider a signal-path device only when it fits the setup
If testing points to a ground loop or an unbalanced source feeding balanced equipment, a compatible DI box with an appropriate signal-ground lift or an audio isolation transformer may help. These are conditional fixes, not universal cures. Confirm the connection type and follow the equipment makers’ instructions. PreSonus discusses audio-chain solutions, while Sennheiser describes ground-loop troubleshooting.
Rank #2
- BLUETOOTH WIRELESS - Popular classic bookshelf speakers now can be enjoyed without the hassle of wires. Simply connection to an iPhone, Android, Tablet, PC or Mac.
- STUDIO SOUND QUALITY - Naturally fine tuned sound reproduction from 4 inch bass and 13mm silk dome tweeter.
- OPTICAL AND COAXIAL INPUTS - Digital inputs to enable lossless connection to most TV and computers.
- REMOTE CONTROL - Adjust the volume and toggle inputs at your fingertips. Bass and treble control located on the side of main speaker.
- SIDE PANEL CONTROLS - Use the side panel knobs to adjust the EQ to your liking. The controls are located on the active/powered speaker.
Keep the protective mains earth connected
A signal-ground lift is not the same as disconnecting protective earth in a power plug. Do not cut off a ground pin, use an adapter that defeats it, or modify mains wiring to silence noise. Mackie warns that disconnecting the safety ground can present a safety hazard. If you suspect an outlet’s grounding, do not open or modify it; contact a qualified electrician. Mackie’s safety warning.
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Check that power and audio connections are secure. If interconnected equipment is powered from different outlets, note that during troubleshooting and consult the equipment manuals before changing the arrangement. Do not assume that moving plugs or changing a power strip is safe in every installation, and do not tamper with outlets or plugs.
Rank #3
- 𝐁𝐥𝐮𝐞𝐭𝐨𝐨𝐭𝐡 5.3 𝐁𝐨𝐨𝐤𝐬𝐡𝐞𝐥𝐟 𝐒𝐩𝐞𝐚𝐤𝐞𝐫𝐬: Pair the bookshelf speakers with your smartphone, tablet, Mac, or PC to play music wirelessly, no need to deal with messy wires. To use your turntable with our Bluetooth speakers: Your turntable must have Bluetooth transmitter/output(for connecting Bluetooth speakers and headphones). If your turntable only has a Bluetooth receiver/input (like most built-in speaker turntables for connecting mobile phones), it won’t work with our speakers. Check your turntable’s specs before ordering!
- 𝐌𝐮𝐥𝐭𝐢𝐩𝐥𝐞 𝐖𝐢𝐫𝐞𝐝 𝐈𝐧𝐩𝐮𝐭𝐬 : The speakers are built with Optical and coaxial inputs and Convenient connection to any device that has a 3.5 mm headphone output or dual RCA output; The Speakers can be Connected with Record Player Directly via LINE OUT, while a Preamplifier is Required if the Record Player has only PHONO output; Plug the speaker wire into "L SPK OUT" on the main to Connect the two speakers
- 𝐑𝐞𝐦𝐨𝐭𝐞 & 𝐁𝐮𝐭𝐭𝐨𝐧𝐬 𝐂𝐨𝐧𝐭𝐫𝐨𝐥: The active bookshelf speaker(𝐃𝐢𝐦𝐞𝐧𝐬𝐢𝐨𝐧 : 𝟓.𝟑 𝐖*𝟔.𝟑 𝐃*𝟖.𝟔𝐇 𝐢𝐧𝐜𝐡) comes with a remote control allowing you to adjust the volume and toggle inputs at your fingertips: mute/unmute, switch to OPT/COAX mode, line-in, and Bluetooth modes. Remote is replaceable lifetime. You can also control the speakers via buttons on top of it; Remote is compatible with Fire TV stick
- 𝐀𝐜𝐭𝐢𝐯𝐞 𝐁𝐨𝐨𝐤𝐬𝐡𝐞𝐥𝐟 𝐒𝐩𝐞𝐚𝐤𝐞𝐫𝐬: This is a pair of active and passive bookshelf speakers which do not require a pre amp, and also built with 0.5 inch silk dome HORN tweeter and 𝟑.𝟕𝟓 𝐢𝐧𝐜𝐡 𝐰𝐨𝐨𝐟𝐞𝐫, bringing you a surround home theater listening experience
- 𝐀𝐦𝐩𝐥𝐢𝐟𝐢𝐞𝐫 𝐨𝐫 𝐑𝐞𝐜𝐞𝐢𝐯𝐞𝐫 𝐢𝐬 𝐧𝐨𝐭 𝐫𝐞𝐪𝐮𝐢𝐫𝐞𝐝, and If you still want to use amplifier or receiver with the bookshelf speakers, please connect via Line Out of the amplifier or receiver.
If the speaker still hums with its signal inputs disconnected after basic cable and source checks, consult its manual or manufacturer support. The noise may be within the speaker or its power environment, and further diagnosis may require authorized service. Neumann presents its KH 120II checks as steps to try before sending that model for service; this is not a universal repair procedure. Neumann’s troubleshooting steps.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Special case: a turntable in the audio chain
If a turntable is connected, check its grounding arrangement according to the turntable and speaker or amplifier manuals. A turntable-ground issue applies only when a turntable is actually part of the setup. Fluance’s powered-speaker guidance includes a turntable-ground check and distinguishes idle hiss from hum or buzz.
Quick Recap
Best Value
- 【No Receiver or Amplifier Required】The RIOWOIS Powered Bookshelf Speaker DS6701NP connects to your turntables, computers, TVs and cell phones WITHOUT the use of any amplifiers or receivers. Please note that powered speakers are NOT compatible with receivers or amplifiers!
- 【Wireless Streaming with Bluetooth】With this bookshelf speakers , you can easily stream your favorite music, broadcast, or audiobooks from record player, laptop smartphone, tablet, or any smart device through Bluetooth 5.3.
- 【Multiple Wired Connections】The stereo bookshelf speakers offer multiple inputs, providing a wide range of uses. The AUX connection is commonly used, allowing easy connection to a record player or computer. Optical and TV-ARC connections are preferred for connecting the bookshelf speakers to a TV, and you can even use the TV remote to control bookshelf speakers via TV-ARC connection(Optical cable and ARC cable not included).
- 【Remote and Button Control】The remote not only enables you to control the volume and power on/off of your bookshelf speakers, but also allows you to quickly switch between inputs, disconnect the current Bluetooth device(pressing and holding the BT button for 1 second) and switch between 3 sound effects. In addition, you can still use the buttons on the main speaker to control the bookshelf speakers.
- 【Reinforced MDF Cabinet】The reinforced MDF cabinet of the bookshelf speakers effectively minimizes crackling sounds. The bookshelf speakers feature a classic wood grain design and hand-polished rounded corners, adding a touch of sophistication and natural to your room.
Rank #4
- 3-Way Powered Bookshelf Speakers: ULTIMEA BS-3 features a 5.25" woofer, dedicated midrange driver, and tweeter for more balanced, separated sound across lows, mids, and highs. The dedicated midrange helps vocals and instruments stay clear, while the woofer delivers solid bass without overpowering the mix and the tweeter keeps high frequencies clean and detailed.
- Advanced Edge Horn Technology: By directing treble toward the listening area instead of scattering energy, this structure optimizes high-frequency performance. It delivers clearer highs and wider sound dispersion, helping vocals and details stay focused and natural across the room.
- Deep, Impactful Bass: Featuring a 5.25” woofer with a 15mm long-excursion and our proprietary BassMX technology, this speaker moves more air to reach deep 50Hz lows with minimal distortion. Experience tight, powerful bass and warm, full-bodied mids that deliver balanced, room-filling audio.
- Powerful 70W RMS Output: Delivering 70W RMS of consistent, high-output amplification, these speakers produce clean, dynamic sound with 0.1% low distortion even at higher listening levels.
- Expandable Home Theater Experience: Transform your living space into a private cinema with HDMI ARC for seamless, high-fidelity TV audio. The dedicated SUB OUT port provides the flexibility to add an external subwoofer, creating a professional-grade, full-range home theater setup.
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