Don’t rule out store brands. I remember seeing the same exact camera lenses under two or three different store brands in the 70s and 80s. I’m sure some hi-fi stores did that with speakers, too.
That the logo is a rock-stock font M with two dots makes me question the level of design involved… it looks like about the level of a local print or sign shop, no more. I’d bet more chips on this being a small-store or private-brand house logo/brand, probably on OEM speakers and systems.
It’s a font called “Amelia,” rather common in the late 60s-70s.
Dell sells them in 2013, on special request.
If the speaker cover comes off, see if there is a brand on the speaker cones. That might tell us if it’s a store brand or a knock off, or a brand that barely existed for 3 months in 1968.
Could it be Wharfedale (and simply be upside-down)?
It looks like a droopy moose staring at two tunnels in the distance - or a house brand.
It looks similar to the middle part of the TMB Bank logo in Thailand. (It was renamed from Thai Military Bank.) Many people wonder why they put a German umlaut above the M, but to me it’s clear those are two heads, and the M is them shaking hands.
In the OP’s logo, it looks like maybe two buddies with their arms around each other’s shoulder.
It looks like a symbol for a special bathroom for conjoined twins.
Trust me - it’s a quickie design done by someone of limited time and talent in a print shop or the equivalent. I just replicated it in about 30 seconds by throwing an Amelia lower-case M on the plate and positioning two period-dots above it. Send to silkscreen shop, done.
It’s either a small-production shop or a house brand for cheap Asian-supplied speakers. It would be nice if the OP could look for more names or indications of quality level.
It looks very familiar but I can’t place it - perhaps it will come to me eventually.
I thought Meridian Audio at first but that was way off 
How is it even possible to have a whitebox made by Dell?
Yeah, I’m positive that I’ve seen that logo before, but I’m likewise at a loss to place it.