Left speaker making a crackling sort of vibration-sound especially on certain tones. Is the speaker shot?

The symptoms you described suggest that there may be several possible issues with your Kustom Bluetooth PA speaker. Here are some steps to diagnose the problem:

1. Check the battery: Ensure that the battery is fully charged or replace it with a new one if needed. If the battery is old or worn out, it may not provide enough power to the speaker, causing the crackling sound.
2. Check the connections: Make sure that all cables and connections are properly plugged in and secured. Loose connections can cause crackling sounds or no sound at all.
3. Check the volume: Turn up the volume on both the speaker and the device connected to it (such as a phone or tablet) to see if that resolves the issue. If the volume is too low, it may result in no sound or faint sound.
4. Test the mic and instrument input: Try connecting a different microphone or instrument to the speaker to see if the problem is with the original mic or instrument. If the new mic or instrument works, then the issue is likely with the original device.
5. Check the speaker components: If none of the above steps work, there may be an issue with the speaker's components. It's best to bring the speaker to a professional technician or authorized service center for repair.

Hopefully, one of these steps will help you diagnose and resolve the issue with your Kustom Bluetooth PA speaker.

Get a meter and check the resistance on the speaker. Looks like a speaker may be blown but with the description of the crackle noise from the slide controls you might have a bad pot in the unit or the pot has come loose from the board. This could explain why the speaker blew out

This sounds like one of this nasty problems with the solder points. One of them might be faulty so sometimes there is a contact sometimes not. You could try to locate it by knocking gently with the plastic end of a screwdriver on the pcb. If vibrations cause the noise you could check all solder points optical or just resolder them. There are not too many. Also check all potentiometers! As they are mechanical parts vibration caused issues can be found here very often especially on their solder points.

It looks like the Korg c-15s has a internally mounted speaker and so I will assume that the speaker and amplifier are part of the piano base. It sounds like either the speaker is blown (crackling sounds heard as deformed voice coil scrapes the magnet structure) or the audio amplifier is distorting the audio.

Connect the piano's output to an external amplifier and speaker to properly identify problem.

Crackling is usally one or two things my guess would be bad grounding of the amp or bad connection with the jacks or plug it self try to make it crackle on purpose by jiggling the jacks see if it has any effect on the crackling try to narrow your possibilitys

It could be that the input jack is or cable is damaged. The input to the right speaker is from the left speaker via speaker cable. Check that wire and try a new one. All speakers are susceptible to some type of interference. Make sure the cables aren't tangled and free from other powered equipment.

Hope this helps

To troubleshoot the problem start with the bit that is working - the left speaker.

1. Unplug the input leads on the back of the left speaker and swap them round.
2. If sound now comes out of right speaker and not the left the problem is with your sound source (computer, IPOD or whatever) or the connecting cable is faulty.
3. If there is still no sound from the right speaker try turning the volume control knob up and down quickly several times - does this produce any sound from the right speaker? Sometimes the electrical contacts get dirty and this can help clean them.
4. Turn the speakers off using the volume control knob. Disconnect the speaker wire for the right speaker from the OUTPUT on the left speaker (push the red and black tabs downwards and gently pull the wires out. Find a small 1.5 volt battery (an AA or AAA size will do nicely) and touch the bare ends of the speaker wire briefly on the battery terminals. If you hear a slight crackling sound the wire and the speaker are okay and the problem is in the amplifier, which will need repair or replacement - not a job for an amateur.
5. If you don't get any sound from the battery test find another piece of speaker wire (any piece of 2 core cable with bare ends will do for testing) and repeat the battery test. If you get sound then replace the speaker wire. If not remove the speaker wire again and go to next step.
6. Lay the speaker face downwards and carefully unscrew the back panel (don't do this if it is still under manufacturers warranty - take it back for repair or replacement). Lift the back panel off carefully and slowly taking care not to pull the connecting wires inside the cabinet, which will probably be quite short. You may have to settle for just rotating the back panel slightly so that you can see inside if the wires are too short to do otherwise.
7. Use sticky tape to tightly attach the bare ends of the speaker wires to the terminals of the battery. Touch the loose ends of the speaker wires on the two metal terminals where the internal wires are joined onto the back of the big loudspeaker cone. If this produces a crackling sound it is the internal wiring in the cabinet that needs re-soldering. Otherwise the loudspeaker unit has failed and will need replacement.

I have a Korg C-15s and also experiencing loud crackling sounds when I turn it on. The problems seems to be either the sliding volume control or the amplifier itself. Honestly though, I believe the issue is the volume control. I opened my piano to get a closer look and attempted to clean the contacts on the volume. Unfortunately after cleaning the contacts, the crackling sounds became somewhat worse. After I turn the piano on, the volume control is generally rendered useless......volume set to low volume and the noise is quite loud and other times the volume control is set high and get very low volume crackling noise. No real consistency. The noise does diminish after a few minutes but so does the piano sounds to an inaudible level. There were a couple of instances where I turned it on and surprising enough, no no noise and perfect sound. For these reasons I believe the issue is within the volume control and not so much the amplifier. I have an electronics background and noticed that the volume control is very unique in design and is not something that can be substituted with another volume control from other sources.

My recommendation is to check the sound quality of the audio from the RCA L/R audio outs on rear of the piano by connecting to a stereo receiver. If it sounds fine you're in luck. If the crackling sound does not diminish after a few minutes like mine does, I would suggest disconnecting the internal speakers and using the audio out only. You can connect a pair of studio monitors or high quality computer speakers, preferably with a small subwoofer to deliver the full audio range and deeper tone of a real piano. I'm currently using a basic pair of Logitech computer speakers and is quite acceptable until I can afford a high quality set of monitors or relocate my piano closer to my high quality Yamaha receiver.

I hope this info helps a bit.

This usually means that the speaker is blown. Try running through a different setup and see if it fixes the problem. Hope this helps

Not likely to be a fuse. The bane of electrical amps are the connectors.

Often the speaker and more commonly the input 1/4 inch connectors go bad. Sometimes caused by side loads when cables are yanked or tripped over.

Be careful of running amps IF the speakers are not connected OR have bad connectors or cables. You can arc over the tubes or pop transistors.

Get a cheap Volt-ohmeter from HarborFreight or Radio Shack and test your cables and connectors.

For a tube amp, your should find relatively low resistance at the speaker connector (certainly under 20 ohms). Do this with power off.