Hi All,
I'm brand new to this community... hope this is the correct forum...
I recently bought a pair of Tectonic exciters, 32mm 30W, and have been testing and measuring them on different panel materials and shapes.
THEY BUZZ!
I am driving no more than 1W at a time, and have rolled them off at about 300Hz, 12db/oct. I'm getting mechanical buzzing on them, even when not attached to a panel, at about 370Hz and 650Hz.
Anybody else had this problem? Any suggestions?
I'm brand new to this community... hope this is the correct forum...
I recently bought a pair of Tectonic exciters, 32mm 30W, and have been testing and measuring them on different panel materials and shapes.
THEY BUZZ!
I am driving no more than 1W at a time, and have rolled them off at about 300Hz, 12db/oct. I'm getting mechanical buzzing on them, even when not attached to a panel, at about 370Hz and 650Hz.
Anybody else had this problem? Any suggestions?
370 Hz is around the impedance resonance which reaches 70 ohms or so assuming I have the correct data. What kind of amp are your driving them with?
Do you want to provide the exact model number of the driver, filter components, and amp details?
Do you want to provide the exact model number of the driver, filter components, and amp details?
Hi Raymond, thanks for your reply.
Here's the exciter datasheet: https://www.tectonicaudiolabs.com/wp-content/uploads/2019/04/T-DS-TEAX32C30-4B_Rev-1.1.pdf
Free-air Fs is 260Hz.
Obviously, when the drivers are attached onto a panel of any description, the Fs reduces closer to the fs of the panel itself, which is generally less than 100Hz depending on the combined mass of the driver/panel/suspension compliance etc etc etc. But yet, the buzzing happens at the same frequencies approx 370Hz & 650. And these two frequencies are not harmonically related (rationally) so I suspect there are TWO mechanical issues here.
I'm using various active cross-overs and concert-quality amps that you could probably weld with if you were in a tight spot... Damping factor on these amps (at the output terminals, excluding speakers and cables) is usually in the thousands or tens-of thousands, which translates to milli-ohm output impedances (not to be confused with load impedance)
It appears that nobody else on this forum has experienced or addressed this problem, so today I'll be taking the drivers apart to see if the rubber seals have maybe come unglued somewhere. The metal spiders seem to be OK since they are screwed into their mounts.
Cheers,
A.
Thanks for filling in the missing information.
Your amps sound like there should be no issues there after reading your description of them.
You seem to have identified an area of concern, so yes, maybe there is something mechanically wrong with them. I haven't used exciters, so my first thought is possibly if driven without being connected to a panel would they be very easy to overdrive. if somebody has tested them before you received them that may be the issue, or possibly they are badly assembled or the glue has failed on the suspension components?.
I have wondered about the use of exciters for testing of microphony in electrical component assemblies but haven't yet tried a quick experiment.
Your amps sound like there should be no issues there after reading your description of them.
You seem to have identified an area of concern, so yes, maybe there is something mechanically wrong with them. I haven't used exciters, so my first thought is possibly if driven without being connected to a panel would they be very easy to overdrive. if somebody has tested them before you received them that may be the issue, or possibly they are badly assembled or the glue has failed on the suspension components?.
I have wondered about the use of exciters for testing of microphony in electrical component assemblies but haven't yet tried a quick experiment.
Right... update.
The voice coil assembly on the right has a soft rubber shroud around it, apparently to keep rubbish out of the pole gap.
That shroud fits around the magnet assembly. It fits loosely. It is not glued down. And it dances around like a hoola girl on hot coals. I tried gluing it down, but the problem although ameliorated slightly, was still there. I eventually just cut it off with a scalpel, reassembled the whole lot, and the problem has disappeared.
Next step: Get better quality exciters.
The voice coil assembly on the right has a soft rubber shroud around it, apparently to keep rubbish out of the pole gap.
That shroud fits around the magnet assembly. It fits loosely. It is not glued down. And it dances around like a hoola girl on hot coals. I tried gluing it down, but the problem although ameliorated slightly, was still there. I eventually just cut it off with a scalpel, reassembled the whole lot, and the problem has disappeared.
Next step: Get better quality exciters.
Speaker coils are not sensitive enough. I use piezo diaphragms as microphones for all kinds of things. Just glue them onto the surface and drive them straight into any mic input. Not the greatest response curves, but they're sensitive.