Adding an additional speaker to Nait Naim 5si speaker output

I have Wharfdale Denton’s 85 (4 ohms) connected to my Nait 5si. Sounds pretty good with most music. Ive attached an old BOSE acoustimass series 3 bass module (4 ohms no high-level input options) to the same speaker output used by the Dentons, The sound benefits from a little but noticeable richness in bass. Is this a safe connection to the Nait 5si if the speaker ohms are the same?

You should connect your sub to the terminals on the speakers themselves, not the amp.

This doesn’t sound like a good idea to me, but I guess if you like it then who am I to say otherwise. AFAIK if the two 4 ohm units are connected in series then the amp sees 8 ohms, which is fine, but make sure both channels are seeing this.

Thanks for the advice – its appreciated. I had success connecting a REL T5 subwoofer using a high-level connection, but Ive lost that speaker to the family rooms TV. The old bose subwoofer – without high-level option – seemed promising as it did add some bass value to the music , and the amp didnt seem to complain, but still, I dont want to risk damaging the amp, so I will abandon this approach.