Over the past several years, the Totem Forests were one of my favorite speakers...the first time I heard them being powered by a set of the Nagra monoblocks was a truly great experience. We very, very rarely had any problems with them that weren't "owner induced"!
But, over the past couple of years I've seen a couple of the Hi-Vi D6.8 drivers used in the Forest that have had problems with the adhesion of the cloth spider to the basket.
It took us quite a while to figure out what the problem was, like you said, it comes and goes, so we took the unit out of the cabinet and ran different frequency test tones thru it until we found one that excited this effect...and found that it was an area of about 1/2" that the adhesive was not adhereing the outside perimeter of the spider to the cast basket...Totem sent us a replacement driver set...(and I repaired the buzzing driver and have them waiting for just the right time to build something!)
I used a small amount of "Goop" adhesive to reattach the loose portion of the cloth spider to the driver's basket. I hooked it up to an amp and a signal generator and couldn't get it to buzz again, so I pronounce the operation a success...
Another time we found a cracked cross over board that buzzed...again, Totem shipped us a replacement set of crossovers...and, once again, I kept the "broken" parts which are also awaiting their inclusion into a project...but only after I do an upgrade of the capacitors and resistors used in them and get rid of all the terminal block connectors (there are 19 connections on each crossover made with these terminals with their magnetic screws, etc.) and use joints made with Cardas solder...if I had an LCR meter I could check the impedence of the two air core chokes used and come up with a crossover schematic...
It seems as if the Forest is a pretty simple implementation of the HiVi D6.8 and a SEAS 25TAF/G tweeter...but Totem Acoustics claim to do some mods to the tweeter...still, though, about $90 worth of drivers in each speaker....$25 of inductors, $5, ok, let's be generous, $10 caps and resistors, $2 terminal blocks and hardboard....add up to $100 for WBT Binding posts, wire, rear terminal plate....now, these are retail prices from places like Madisound, Parts Express, Handmade Electronics, etc., not the prices a manufacturer gets...so, under $300 wholesale for parts minus the cabinets for a pair of $3K speakers....hmm, wonder why we DIY?


Let's see, according to Hi-Vi, build a 12 liter box with a 1.5" ID X 5" long port for the woofer, add a SEAS tweeter, build a crossover, add some nice Cardas binding posts, wire with your favorite wire, and even using solid silver wire, you'll save over $2K....even if you have to have a Totem dealer order you a set of the feet that's used on the Forests....
Than again, after hearing the new Audio Physic Tempos, Sparks, and Yara Evolution floorstanding speakers (in the same systems we used to use with the Totems) I have come away with a greater appreciation of their tweeters, which look a lot like the SEAS Excel T25C series, and the resultant transparency, clarity, and freedom from grain of the AP speakers in the upper reaches is greater than anything I previously heard from the Forests....if it is the Excel tweeter, than Madisound lists that tweeter alone at a price very similar to both of the drivers in the Forest...
So, check out the spider and see if that's where you're hearing the buzz....if Totem won't warranty the speaker, they're available from Parts Express:
http://www.partsexpress.com/pe/pshowdetl.cfm?&PartNumber=297-444&DID=7Good Luck!