The BA 735 speakers that came with the old Gateway I have does not work with the new iMAC

https://www.techwalla.com/articles/how-to-connect-boston-acoustics-ba-735-speakers

https://www.sevenforums.com/sound-audio/315384-how-use-my-digital-speakers-analog-out-pc.html

The speakers apparently use a RCA Coax S/PDIF digital input. The speakers may have delivered with a USB to S/PDIF conversion cable if they were the USB version. Otherwise, you will need either a USB to S/PDIF converter, or a analog (L+R) to S/PDIF converter.

There is also a suggestion on some posts that the BA 735 speakers sold by Gateway computers were somehow non-standard. Your results may be variable.

Many of the new sound cards and especially sound cards on OEM do not support digital speakers without buying additional connectors. (Not sure why. I have these same great speakers for years and they are wonderful.
- Check if your sound card ha an SPDIF connection option. - Check the speakers in the device manager to see if you can toggle the "digital" option. - I also have read that some versions of the BA 735 have an analog option on the back of the subwoofer if you need to bypass digital. (mine don't, so I don't know if this is accurate)

if now your computer not support this speakers,you must buy new soundcard support this speaker then build in to your computer hardware.good luck

with this program http://www.radarsync.com/ is free .

The BA 735 Speakers I have are purely digital and will only work if your soundcard has a digital output, will not work through the normal analogue green socket .

Partial Solution anyway - I just got a Mac Pro (2.66 Nehalem )and couldn't find the manual from my old Gateway 700XL. This is what I did: Plug the green wire into the analog output, and the pink wire (if you really need an external mic, but you shouldn't since our new computers both have a built-in mic) into the analog input. Just ignore the black wire. You won't have the 2 surround speakers, but I'm still looking for a fix for that. I got tired of the crappy speakers in my new Apple Cinema display (the ONLY crappy thing about my new system). As you know, the sound from the BA7800 is great, even with just the two front speakers and sub-woofer. I'll keep you posted if/when I figure out how to set up the surround speakers! Likewise, if you hear something, please post here and I'll keep checking back.

Go to www.neoseeker.com/forums/153/t1017397-boston-digital-ba735 and read.

do i need a disk to dwnload these to work on my computer

Use the "Analog In" jack on the sub-woofer and NOT the " Digital In". That's when they start working.
sumother set of these SAME speakers DOES NOT have an "Analog In" jack. So give them to a local thrift shop.

note: Boston makes 2 different speaker sets with the same name,
BA 735: one with and one without the "Analog In" jack.

Open the sound settings from your control panel. click & open all possible icons & options & change it & remember it what you done and try by combination. one of the option like boost/ line area may be deseabled so the problem occur.