Recently I had great result by adding two 18 inch Scaena subwoofers to my Lansche 4.1 speaker.
You may want to contact Mark Seaton to get advice on subwoofer to add to your speaker.
https://seatonsound.net/product/f18-subwoofer/
https://www.whatsbestforum.com/threads/what-is-the-most-musical-fast-and-accurate-subwoofer-you-have-heard.21597/page-4
You may want to contact Mark Seaton to get advice on subwoofer to add to your speaker.
https://seatonsound.net/product/f18-subwoofer/
https://www.whatsbestforum.com/threads/what-is-the-most-musical-fast-and-accurate-subwoofer-you-have-heard.21597/page-4