I got the model number wrong, this is in fact the KS-SW100, the one I pulled up on the computer is the HI-Fi version (NS-SW100). They seem to look very similar and are the same price, sorry for the mix up :)
https://europe.yamaha.com/en/musical-instruments/keyboards/products/accessories/ks-sw100/

Good idea never thought about a sub….it’s a great hack. If you just say sub you will not make every American cringe when you say woofer. Love you Woody.

YAMAHA DGX-670 is my favorite piano/keyboard.

A good upgrade is changing the 3.5 floppy drive to a USB
I put one in my PSR 740 & now I have my backing tracks with lyrics on USB, up to 1000  3.5 floppy’s saves keep changing floppy’s

Agree, I have a bigger Sony unit with many features that I have used on all my sound and keyboard systems including a Sony amplifier with various inputs so I can play along with music inputs from other sources, older equipment from pre keyboards era put to good use.😊

I found that it very much depends on the size of the room you are playing in. In my home studio a sub woofer doesn't work as it's too boomy and you won't get the really deep bass notes due to the resonant wavelength versus the room dimensions.  Even in our lounge I found my Mission hifi speakers with 6 in woofers deliver similar sub bass to a 10 inch separate sub unit in the corner.  I think where this really comes into play though is in a venue - in a bigger room or hall the sub will deliver bass levels that aren't possible from smaller speakers.

My jack russell Mr Twiglet was in service to the Royal Navy as a guard dog on a submarine - he was affectionately known as a Sub Woofer ! Woof Woof.....

:hand-purple-blue-peace::hand-purple-blue-peace::hand-purple-blue-peace:

I have the SX 920 , upgraded it from an S770. The SX 920 is a fabulous keyboard. Portable and about 80 % of the Genos 2 for about half the price. Thanks for great advice.

Woody!!! I loved your wonderful Keyboard my friend!!! Everyday I watch your channel no stop

Train in background priceless

I don't have a sub woofer but I do put another speaker on the floor and it really brings it out and makes it fuller...  I agree!!!

100% agree with this. Even my Kawai NV10 benefits from a subwoofer to fill-in the low end. I’m using a 30-year-old Yamaha unit from a multimedia PC rig. Does the job.

The SUBWOOFER upgrades indeed the sound quality of the keyboard instrument, but it does not upgrade the instrument registers and/or organ flute pipes registers. For organists, it is best to explore Hautwerp to simulate pipe organ registers conneced via the keyboard's MIDI Ports. I am not aware, but I am sure, there is a similar instrument register upgrade for synthesizer sounds.

I got the same KB. I have a Yamaha studio monitor I got at a discount too but before I got it I was using a 25 year old Sony home Dolby Prologic stereo system that has the standard 5 speakers including a similar sized subwoofer as yours.

We discovered exactly the same thing about two years ago when we connected a small "the box pro Achat 108 Sub" to our old Yamaha CLP-150. The piano, with its 2x60W, has plenty of power, but the subwoofer, which is almost invisible in the lower part of the piano, gives the notes a certain foundation that even grand piano sounds benefit from. Greetings from Germany! 🇩🇪🤝

I had the sx900 great keyboard however now have the genos2 with sub and hs8’s massive improvement 🤗👍🎶

The outstanding onboard speakers in the also fantastic Kawai ES60 remain active when connecting external speakers/sub as one would here. That is something to verify with your model before buying.

Just tried this with my DGX 670!  Night and Day!  The internal speakers are fine, but with a subwoofer, the thing comes alive.

Yamaha is top tier in the arranger/keyboard market. Synths they also do very well.