A:AnswerUnder the default settings, the Yamaha RX-A780 is configured for 8Ohm speakers. You're unlikely to hurt the speakers, using an 8-ohm receiver with 4-ohm speakers. This just means that for a given voltage supplied by the receiver, the receiver is rated to send less current than it will have to power the 4-ohm speakers, so this is much more likely to hurt the receiver than the speakers. You may contact JBL Synthesis Customer Support if you have other questions and/or concerns. https://bit.ly/3uir2W7
A:AnswerJBL HDI-1600 is handled by our HARMAN Luxury Division. It is not an upgrade of the JBL ES30. However, you may consider getting it if you're looking for a louder bookshelf speaker than the JBL ES30.
A:AnswerThanks for the feedback you've provided with our JBL - HDI1600. For assistance with product recommendation and set up, please reach out to our support for JBL Synthesis products here: https://www.jblsynthesis.com/support/contact.html
