CurtPalme.com Home Theater Forum

[JustGreg]

I have a pair of Yamaha mains that are around 25 years old that I just tore apart and quasi rebuilt with new tweeters and crossovers and got to wondering if the woofer foam can be treated with lanolin or the like to keep them supple. I haven't done anything to them yet while waiting for a reply. If nothing can be done (or should be done) I guess I'll run them until they drop and replace the entire woofer (as opposed to refoaming...it would be wiser to buy newer speaker technology replacement woofers IMO).

One a related note, I replaced the no existent crossovers (simple caps crimped in line ) with some decent 8ohm 3-way boards. The sound is warmer now but I'm finding I have to push my aging Onkyo receiver harder to achieve the same output. Not knowing much about speaker building I'm wondering if the speakers were mismarked and are actually 4ohm or if the crossovers were mismarked with the same problem. Or...I suppose it could just be that more components in the chain are responsible. I realize asking such generalized questions is akin to shining a flashlight into the Marianis Trench and expecting to see the bottom but I'm really starting to get interested in what makes a speaker speak and well, we all gotta start somewhere right?

Thanks guys.

[jkruger]

My old girlfriend had a male cat that "treated" my speakers once. Cat died mysteriously soon afterward. Girlfriend left a week later.
Good riddance to them both.

[Curt Palme]

If it is the foam, it has a life span of about 15-25 years depending on how exposed it is to UV rays. I don't think it can be treated, just get the speakers refoamed when they deteriorate.

[Curt Palme]

If it is the foam, it has a life span of about 15-25 years depending on how exposed it is to UV rays. I don't think it can be treated, just get the speakers refoamed when they deteriorate.

[kal]

Or get new speakers. They haven't used foam surrounds in reasonably good speakers for years.

Re: Speaker impedance: It's not hard and fast rule - no speaker is truly 4 or 8 ohms (or anything else). The resistance (impedance) changes with frequency. What is rated as an "8 ohm nominal" speaker could easily dip as low as 2 ohms in the low frequency range.

Kal

[kal]

Or get new speakers. They haven't used foam surrounds in reasonably good speakers for years.

Re: Speaker impedance: It's not hard and fast rule - no speaker is truly 4 or 8 ohms (or anything else). The resistance (impedance) changes with frequency. What is rated as an "8 ohm nominal" speaker could easily dip as low as 2 ohms in the low frequency range.

Kal

[garyfritz]

[Tom.W]

Ozone also dissolves the foam surrounds. Old rubber bands also loose elasticity and easily break due to ozone.

http://en.wikipedia.org/wiki/Ozone_cracking

Several of the earlier Infinity speakers died because of the foam surrounds on the woofer and midrange cones dissolving...

[JustGreg]

Interesting replies...especially the one on how to lose two pussies in as many weeks.

That's great info Kal...I stumbled across the same stuff today whilst beginning my Speakers for Dummies sojourn. I've already decided to replace the entire speaker. They aren't any great shakes to begin with and I have no emotinal attachment but the cabinets are in great shape and are just begging for a second life.

I began by selecting a 3-way 2nd order x-over that lends itself (by design) nicely to what I'm attempting, eg, recycling older components in and out as I learn. Much like a Radio Shack electronics starter kit this x-over is flexible and forgiving.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-152

I resisted the temptation to spend more than I did because at this stage I wouldn't know what I was hearing anyway. Armed with a fairly adequate supply of decent quality caps and inductors, and in conjunction with speaker testing software, my plan is to use them as breadboards that will eventually be tuned to the cabinets and room. (If they survive repeated component swaps that is).

Because I have tinitus I tend to max out the higher frequencies at the receiver so I drive the tweets hard. Their demise is no secret. They were old and I drove them hard after the towers were in storage for about 10 years. I was really tempted to replace them with horns but because they'll be seen (HATE speaker grates and cloth!) I want to achieve great high frequency reproduction without show stealing carny looking horns. So I settled on these:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=275-130

The Tim Allen part of my brain wanted to buy these for their wider coverage area but I'll get them later after I learn how to validate (read=software) options:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-536

For overload protection I've added the following:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-805

I suppose I could have used the lamp/fuse but that would require opening the cabinet and soldering in another whereas the self resetting breaker only requires a minute to reset....and future restraint on my part.

Lots of fun so far!