I swapped the drivers from one cabinet to the other to rule out any crossover issues. During that i would have tightened down the bolts to an acceptable max. It didn't change the sound.
I suspect at this point it is likely a slightly out of alignment voice coil, possibly from gravity sag over time. It is also possible that the coils in both the Missions and Tannoys are ok and for some reason as you mention, a specific frequency, is causing the sound but then if the paired driver in the other cabinet isn't doing this, i would say the suspect drivers are somehow out of spec.
Considering the cost of the Tannoys (aside from the fact that i don't have the workbench, materials, time or practiced skill to undertake a voice coil realignment) i'll be bringing the unit to a local repair shop with a fellow on staff that knows speakers really well. Just hope that there's nothing unrepairable such that i have to go and find some old stock driver which would be a rather difficult hunt i think.
As for the Missions, well, they are circa 1982 and might just be up for the sale block to someone that wants to take the time to sort them out. The cabinets are in rough shape. I haven't used them in 4 or 5 years up until this week, so probably time to move them on.
Last edited by chesseroo; 04/24/21 05:10 PM.
