Hey all, thanks and sorry to have been such a noob, and not think of break-in before running this up a flag pole
Usually the manufacturer lists the use of ferrofluid in their drivers, though in the 291 page Meyer Sound Design Reference manual there was only one mention.
Burn-in and resonance verification were on the same page 😉 :
Long term, kerosene based ferrofluid thickens up as the volatile hydrocarbons evaporate. Thicker ferrofluid has more damping, which could affect the impedance.
I mentioned it because of my recollection when early Meyer MSL3 systems using ferrofluid were brought in from the cold in Minnesota, engineers would run them near full tilt for a long time before tuning them, as the response changed quite a bit as the oil heated up.
Some ferrofluids are kerosene based, kerosene has similar viscosity to diesel fuel, which in winter could gel to the point where it would not flow without pre-heating.
Art
^^^^^^ That.
From day 1 I suspected "something" heavily damping that speaker, big time.
Any "fluid" sitting still for 10 years will most probably be a thick goo by now, think honey thick or so, imagine that gap filled with honey. 😱
From day 1 I suspected "something" heavily damping that speaker, big time.
Any "fluid" sitting still for 10 years will most probably be a thick goo by now, think honey thick or so, imagine that gap filled with honey. 😱
It doesn't appear that the driver in question, the ST-815 has ferrofluid.
I don't know that for certain, as i can't find any direct specs.
My thinking comes from a description in the Meyer M3D sub brochure, that contrasts its use of two rear firing ST-815s, with two other front firing 15"s that the brochure specifically touts as having ferrofluid with rated for 2X the power of the ST-815.
My best guess so far is 10 years of lying in one position makes anyone/anything a little creaky 🙂
Hmm, you reminded me I have two NIB 421-8H Altecs I haven't rotated in at least a decade, so sure enough, they've bottomed out. 🙁 Oh well, next sunny day, Hotlanta's Summer heat cooking my concrete sidewalk will solve the problem PDQ. 😉
Add to that mounting them somewhere, and pumping some music through them, it should help to self correct centering.
Couldn't find that brochure 😉
Both the Meyer M3D Line Array Loudspeaker and M3D-Sub Directional Subwoofer use MS-815, not ST-815) 15" drivers.
The M3D-Sub uses the 4 ohm 1200 watt 4" voice coil MS-418N(neodymium) 18" on the front side, the
8 ohm 3" voice coil 600 watt MS-815 on it's rear side.
The M3D uses the 4 ohm 1200 watt MS-415N(neodymium)15" on the front side, the 8 ohm 3" voice coil 600 watt MS-815 15" on it's rear side.
Your 15" 3" voice coil ST-815 has no pole piece back vent, seems about as likely as not it may use ferrofluid cooling.
That said, unlikely a 10 year old driver from Meyer Sound would use the hydrocarbon (kerosene) based ferrofluid materials more commonly used 40 years ago.
Anyway, a call to Meyer's service department probably could end the speculation.
Art
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looks like you pulled connection drawings from the Operating Instructions. The first page of them was the "brochure" i was pulling my info from.....
Yes, the MS-815 was original equipment.
It was discontinued , and the ST-815 is the replacement for all products previously using the MS-815.
(That info is on a sheet that came with the ST-815)
Yep, I may have mixed up whether i was talking about the M3D, or the M3D-Sub. But in either case, the way i read things (which may be wrong) , only the neo drivers have ferrofluid.
It does have a back vent. It's a very fine mesh that the pict posted doesn't show well, if at all.
Yep, although unless the driver goes back to misbehaving, i probably won't bother...
Ok sorry my bad, I just looked at the 4 way speaker it was used in back in the day and it looked alot like a kick/midbass driver more than a sub as the 18" would deal with the low end I assumed this 15" main "job" was to ensure strong chest kick around 150Hz. 🤔
kerosene based ferrofluids are not specified for audio use. They are completely unusable for this application and meant for other applications.