what does 2x 4ohm mean in a driver?

[3rutu5]

guys, i bought this Visaton W130 X - 2x 4 ohm driver last year in order to use it as a sub on a 2.1ch build, which i'm still planning to do with my latest chats about minimal desk setups and small pc speakers.

https://www.visaton.de/en/products/d...30-x-2-x-4-ohm

it mentions that you can hook up one voice coil, or both either in series/parallel, which has thrown me a little. I've seen some basic bluetooth builds where there has been 2 woofers and a shared tweeter, but pretty confident in my thinking that you cannot just hook each voice coil to a different channel and share a sub in the same fashion? ie do a fast crossover and combine for the sub. Am i correct in thinking this?

I'm still thinking about my amp selection as it needs to be small and minimal, but i have a no name 2.1ch amp (2x50 and 1x100w) and a wondom 2x50w bluetooth board with DSP, which the later i bought for my phantom clone, but then realised it didnt have the charging chip and i ended up going the mono 60w amp instead. I also was thinking this could make a bit of noise in a bluetooth setup, as originally i got the peerless 2.5inch full rangers (830985 https://www.parts-express.com/Peerle...oofer-264-1050) which can be in a small sealed box 0.01cuft with a F3 of about 140hz. Only issue is i only have two ears and with an autistic child i dont always get to crank up the volume and i seem to have quite a few small BT builds to date,

I like this woofer as it can get an F3 in the mid 40's and be in a enclosure of 0.140-0.15cuft, which is quite compact for a 5 inch, well i think it is.

being mounted under a desk facing downwards, i dont know if a BSC is required as it will probably have a low pass filter around the 150/200hz range, but interested to hear some thoughts on it.

[billfitzmaurice]

pretty confident in my thinking that you cannot just hook each voice coil to a different channel and share a sub in the same fashion?

That's exactly why dual voice coil subs were invented. Long before AVRs with LF outputs dual coil subs would connect one coil to the left channel and one to the right of a stereo source, either actively or passively crossed over, usually passive. That configuration is seldom used today, because of not only the LF outputs on AVRs but also because low frequency content has been mixed to mono since the 1980s.

[a4eaudio]

it mentions that you can hook up one voice coil, or both either i series/parallel, which has thrown me a little.

You can hook up a single voice coil and have a 4 ohm driver. Hook both up in series and have an 8 ohm driver. Hook up both in parallel and have a 2 ohm driver.

The 2 ohm option was probably meant for automotive use but many class D amps can handle that so it might be an option for you.

[3rutu5]

Oh right, see I was a little off the mark with the confidence...I finally hooked them up with the BF37 full ranges I had from an abandoned project, 0.01cuft with a 30mm passive membrane on the back. Sounded ok hand some.rattling from the w130 which is most likely due to be mounted rough in a motherboard box and some bolts quickly added, also no port and flimsy overall it works so that's a start