Monitor 7C’s in garage without temp/humidity control

adam2434

Any folks using vintage Monitor or SDA series in their non-climate-controlled garages? If so, can you share any issues you’ve encountered, or any preventative measures you’ve taken?

I have been using Monitor 7C’s in our garage for several years. Garage is not climate-controlled and we live in SW Ohio, so I’d guess that the garage temp can swing from well below freezing to 100F plus, based on season. They also see large seasonal humidity changes, I’m sure. They stay in the garage all year round, but are only used in around 45F plus temps.

It is really quite amazing that nearly 30 year old “indoor” speakers have not developed issues after several years of temp and humidity swings (knock wood). This is quite a testimonial to the quality of driver build and adhesives used.

I upgraded to RDO tweeters a few years ago. I also refreshed/upgraded the crossover caps and resistors last year, and glued around the MW magnets to prevent shift. I also periodically check screw tightness and do the push test for air leaks.

These upgraded 7C’s really sound great, even mounted high in the corners of the garage, angled down. I’ve briefly experimented with several other bookshelf speakers in this location (recently NHT SB3, Polk S20, and Elac B6.2), and none of them sound nearly as full and clear as these upgraded 7C’s. Basically, I have not yet found a pair of bookshelf speakers that could replace the 7C’s, if they were to fail.

So, lately, I’ve been thinking of scenarios to keep them alive, if something should fail.

Tweeters: new RDO’s from Polk, assuming they are still available.
Midwoofers: new MW6502 from Polk (if available?), or used.
Passive Radiators: possibly find used ones, could be difficult.
Cabinet: possibly glue/seal interior seams.

Regarding the cabinet, I do wonder how susceptible to air leaks they become after years of temp and humidity swings. Has anyone experienced air leaks due glue joint failure? Would it be a good idea to seal/reinforce the interior glue joints with liquid nails or something else?

Viking64

I have a pair of SDA 2.3TL's that I have stored in non-climate-controlled environments in both Florida and Vermont. Probably about 7 or 8 years total of their 27 years of age.

I did a full restoration last year and I did not encounter any apparent effects from their storage environments. As a matter of fact, other than issues caused by blown tweeters, they still sounded absolutely amazing before the upgrades.

Dabutcher

I use a pair of M7’s in my garage system. Still sound amazing ten years later. Peace. D

verb

One thing comes to mind - humidity.

I see a lot of fasteners on the Polk's that have rusted over the years. Certainly you could paint em and that would take care of it.

Any raw metal exposure on the speakers, XO's, etc., would IMO eventually cause em to deteriorate.

The cabinet would also over time would be subject to humidity and eventual deterioration. The inside is not sealed, so any leaks or even humidity transfer through the speakers would eventually take it's toll. You could paint the inside if you're going to re-seal the cabinet anyway.

FWIW, just my thoughts.

Emlyn

I agree there will be some deterioration over time but since they have been ok for a few years there already I wouldn’t worry about them. The cabinet materials are not real wood so they are fairly stable. The drivers are doped paper and butyl rubber which are both very stable. Similar materials are ok in cars for a long time. Anyway, a garage presents a fairly stable environment over time, meaning the temp and humidity levels change slowly. After a long time the passive radiator may delaminate, but that could happen anywhere. Just don’t store them on a concrete floor or the cabinets will soak up moisture and pop the seams.

I would be more concerned about the electronics driving them, but also not much.

mlistens03

verb wrote: »

One thing comes to mind - humidity.

I see a lot of fasteners on the Polk's that have rusted over the years. Certainly you could paint em and that would take care of it.

+1 here, my LSis have rusted screws, and it bugs the crap out of me. And I can’t find any black paint to fix the issue! Ok for real though, I’m not going to put money towards cosmetic upgrades until I get the sound upgrades done (at least new amp and 2 channel receiver)

adam2434

Thanks for the replies.

The fasteners are not rusty and the metal in the crossovers showed no signs of moisture corrosion when I worked on them last year.

Regarding cabinet leaks, I guess as long as I have decent push test results, I can assume that the cabinet joints have not developed leaks.

BTW, my electronics are in the house, so no worries there.

One observation from earlier this year is that one of the RDO tweeters did not like temps below about 45F. It produced some distortion - kind of a scratchy sound, so I stopped using them until the temp got above 45F.

mlistens03

adam2434 wrote: »

One observation from earlier this year is that one of the RDO tweeters did not like temps below about 45F. It produced some distortion - kind of a scratchy sound, so I stopped using them until the temp got above 45F.

Hmm... that sounds like voice coil scratching, maybe the glue failed under that temp, but then why would it go back?

adam2434

mlistens03 wrote: »

Hmm... that sounds like voice coil scratching, maybe the glue failed under that temp, but then why would it go back?

Not sure. I was guessing that it could possibly be a temp-based dimensional tolerance thing, possibly also involving ferrofluid deposition and viscosity, perhaps leading to a slight rub when parts are cold. Pure guess though.

Issue totally goes away in warmer temps, so I don't run them cold to avoid the chance a permanent damage.

K_M

I think a lot depends on whether the item is stored permanently or simply taken from warm and then into cold and back and forth.
Something stored permanently, will gradually absorb and loose temperature and humidity, as with all items in a garage up north.

Our house in Pa, has all kind of items stored in a garage year round and none are rusting or falling apart nor show signs of age.

Jstas

I think the biggest issue isn't so much humidity but air movement.

Humidity certainly isn't good if it's excessively high. But it's necessary in homes to keep stuff like static electricity down and prevent damage to stuff like wood fixtures and/or furniture.

Your average home, if the HVAC is properly managed, runs between 40% and 50% to be comfortable. Lower than 40, stuff starts drying out and things like veneers can come unglued as the retract. Finishes on stuff can alligator, blister or crack because stuff is shrinking as the air sucks the moisture out of it. You also get problems with static electricity build up on everything.

Over 50% and it starts to feel like a morgue, gets stuffy, dank and musty too. Also, mold and mildew start growing.

I've had stuff stored in the attic for years and that's not climate controlled, gets hotter than comfortable regularly, colder too and it doesn't have any problems but a good layer of dust and cobwebs. But the air in the attic moves.

Not to say that you want to keep a garage packed with stuff and think you'll be OK. Just look at what your stuff looks like after it comes out of a storage unit if you ever had the luxury of needing one of those.

But to leave stuff in a garage, provided your garage doesn't leak and is doing it's job of protecting stuff from the weather, the air movement around them is what is critical. Moisture makes things rust. So do pet and people bodily oils and such. It also grows stuff like mold and mildew which can permanently damage speakers.

But if you are in a garage often enough to use the speakers as garage speakers, you're going to notice problems with the environmental management before they become issues...I'd hope at least.

At least that's been my experience here in the Northeast where it rains often and we see 90-100 degree summer days with 90%+ humidity and single digit temps in the winter where it's 0% humidity because the air is too cold to hold any moisture. Temp extremes aren't any good for speakers or electronics but moisture/water is by far more damaging to them than temps and ambient humidity levels. Humidity levels can be an issue but if you have standing water or leaking water, that will drive the humidity up in an area where the air doesn't move, like an over-packed storage unit or the corner of a garage. If the air doesn't move, nothing will dry out and then the water/humidity lets stuff grow and damage your speakers. Air movement is key in that respect.

If you live down the shore (near an ocean beach) the salt air is far more damaging because of the salinity of the humidity. It eats electronics up because it's corrosive.

Jstas

Oh, also, VC's are pretty tight tolerances for a coil of wire around a former to move around in so violently. Copper is also pretty thermally active (meaning it expands and contracts pretty far) and at extreme temps the voice coil could restrict enough to scrape a pole piece. That would manifest in scratching sounds.

However, tweeters are very light drivers and temps outside the recommended operational range can cause them to become rigid and brittle. That too can cause distortion that would manifest in scratching sounds, especially if, for instance, a polymer dome tweeter has a crack in the dome. Sub 50 degree temps might cause the polymer to contract enough that it would open or cause a crack to form and that would make the two edges of of the crack to rub together. You might not hear it when it's warm because the polymer is flexible enough that it just does it's thing but if it gets cold and brittle, it can scratch and vibrate.

Also, one other thing, if the VC is contracted, it might be tensioning on the tinsel leads abnormally and they could be scraping against cone or other forming structure (surround, motor structure, spider, etc) under operation and that can sound like scratching as well.