As mentioned in the article “Why are my speakers producing excessive noise?” Hissing/Hum is commonly linked to noise within components of the system or a ground loop.
Hissing is the cause of High frequency noise within components of your system, when looking into this issue it is worth starting with your amplifier.
One easy way to rule out an issue with your amplifier is by changing this out for another (if this option is available). If the fault is still noticeable then it will most likely lie within a different section of your setup.
Alternatively, if the fault is only audible in one of your speakers it is worth changing the channel this speaker is being run on to rule out an issue with the amps output channel.
Hum can be the cause of a ground loop within your system. Ground loops can be caused if two or more different points within a system that should be at ground reference have a difference between them.
If you have the option to it is good practice to ground your speakers, amplifier and audio source. Your user manual for all equipment will provide some guidance on how to do this.
Alternatively, we do have a wide range of Knowledge Base Articles which cover this subject for speakers within our range that have this option.
If the above does not resolve your issue, please investigate the following articles:
If none of the above has resolved the issues you are experiencing the last point of reference will be within your speakers. If your speakers are under warranty at this point, we would recommend reaching out to your place of sale to organise a warranty inspection/repair of the speakers.
If your speakers are no longer within warranty, please feel free to submit a support ticket for further assistance.