Breaking in speakers, for a second time?

[nightflier]

OK, this may sound strange, but if speakers need to be broken in initially to loosen up the cones, then would it not follow that after being stored for some time (i.e. several years) they would need to be broken in again?

As a side question, is it also possible that the cones will sag over time? Since they are heavy, they will naturally be affected by gravity, right?

[dingus]

i have heard that rotating the driver 180º can sometimes correct "cone" or "basket sag".

i have a pair of Wharfedale W-60D's (made in 1968) that were dormant for a number of years. when i first got them they sounded tinny and distant. after a few days they began to "wake up". it took a few weeks of steady use before they sounded right.

[nightflier]

1968 is quite old. Do they sag at all?

[dingus]

not that i can tell. the woofers have pleated cloth surrounds that dont appear to have suffered any deterioration. no sign of voice coil rub or any other problems when listening.

[SlumpBuster]

Cones aren't heavy. Baskets and motor structures (magnets) are heavy. A well designed cones will be light and well suspended by its spider. So much so that cones will foam rot will still sound okay at low volumes even with the surround entirely rotted out. A sagging cone sounds suspiciously like a taco bender.

But, I suspect that a driver is like any other mechanical device. It can degrade from lack of use.

[hermanv]

OK, this may sound strange, but if speakers need to be broken in initially to loosen up the cones, then would it not follow that after being stored for some time (i.e. several years) they would need to be broken in again?

Yes they will need a refresh on the break in. It will take far less time because the cones are already crinkled (I don't know a better word).

If they've been stored long enough, the flexible bits will be dried out and they'll never sound the same.

[kexodusc]

I'm amazed at how many so-called objectivists will deny break-in is a real-world phenomenon.

When I buy new drivers (woofers especially) and measure the T/S parameters straight outta the box, Fs is often considerably higher than spec...If I run the driver with some good bassy music for even a few minutes, the resonance frequency approaches spec...that's just the physical break-in of the suspension/surround etc and maybe the motor in some cases (I doubt it, but maybe). By 10-20 minutes of music the driver quits revealing any changes in Fs beyond trial error and is broken-in for all intents and purpose. I'd say most take a good 4 minute song, but subs need a bit more - volume dependant of course.

Measuring them again after months of being idle doesn't reveal anything suggesting they need to be broken in again, but I think it's a logical assumption that at least some resistance to cone movement is present the longer a woofer enjoys resting in a fixed position.

Woofers can sag over time. Though in most cases, the suspension is more than strong enough cripple the effects of gravity. When it comes to subwoofers, which are obviously heavier, we usually crunch a bit of math to calculate driver sag using gravity as a variable...if the sag is greater than 5% of the driver's excursion - increasingly less common these days - a sub will experience noticeable sag and can't be used in downfiring or upward firing configurations, but if it's worth its salt, standard upright placement should be immune to gravity effects. In many cases, sag in a downfiring position will still be only a few %, that's a few % of a few milimeters, extremely tiny, and inaudible for all intents and purposes. I suspect manufacturing tolerance variances from one woofer to the next would be larger than sag effects.

[Bernd]

In my experience far too many speakers are not given the luxury of a decent break-in period. Even at some dealers, brand new speakers are being used for demo purposes.
2,3 or 400 Hours are not unusal for a speaker to really come on song (pardon the pun).
Since I got my new speakers in Feb. I have definitly noticed them going through stages of improvements over the past months.Like loosening up.
I am not sure about running in for a second time though.

Peace

Bernd

[bobsticks]

1968 is quite old. Do they sag at all?

[Resident Loser]

...a good laugh, particularly on Friday as it sets the tone for the weekend...

Obviously anything mechanical will have a break-in period...from shoes to automobiles...your mocassins will take some wearing to conform to your feet and the hundreds of moving parts in an internal combustion engine should be gently proded into their optimum state. As I recall they used to be filled with "break-in oil" that needed to be replaced at a specific time with normal oil...motors, not your sinister footwear...

I'd say loudspeakers require less time than your mocs...and that's if they need to be done at all...As Kex suggested a few minutes should be quite sufficient...the only moving parts are the surround and spider, so once it's compliance has become spec'd, that's pretty much it...You certainly don't want the diaphragm to change, it's rigidity level is a part and parcel of it's performance; any unwanted flexing would bring about distortions.

I'm not a mathemetician, nor do I pretend to be one, but I do recall from HS geometry and physics (40 yrs. ago) that a circle and it's close relative the arch have very specific mechanical pluses...and that is the equalization of loads and stresses...a forward-firing cone will have negligible "sag" perpendicular to it's center axis because at various points around it's perimeter there will be loads and tensions that will "negate" each other...If there is any sag, it will most likely be due to the deterioration of the surround which will disturb that mechanical stasis...In an acoustic suspension loudspeaker that will allow air into the chamber defeating it's purpose entirely; I'd guess other types of enclosures will also exhibit some sort of anomolies...Additionally the voice coil gap is small enough that such a sag or any other deviation of the voice-coil from absolute perpendicularity to it's front plane (or misalignment to the pole piece) will probably result in a very unpleasant rubbing sound...

Upward or downward firing drivers are another thing...Deterioration or loss of elasticity of the suspension components may, depending on coil height/gap height construction ratio, may simply result in bottoming-out (upward firing)or over-excursion (downward firing)...noise, possibly outright failure and at the very least a loss of efficiency which may manifest itself in other ways.

So in a nutshell ('bout time!!!) IMO need for an excessive break-in is highly debateable, "sag" or other mechanical misalignment is simply a precursor to catastrophic failure and a second "break-in" (particularly in an effort to overcome age based deterioration as previously outlined) a pipe-dream.

And of course this pertains to dynamic drivers...tweeters are even less susceptible, piezo units not at all and electrostatics are a whole 'nother ball of wax...

jimHJJ(...if the flexible bits are dried out, they're just about to cr@p out...)

[bubslewis]

i have heard that rotating the driver 180º can sometimes correct "cone" or "basket sag".

i have a pair of Wharfedale W-60D's (made in 1968) that were dormant for a number of years. when i first got them they sounded tinny and distant. after a few days they began to "wake up". it took a few weeks of steady use before they sounded right.

Have you ever considered upgrading the crossovers in those old Wharfdales? My father has a pair of WD 70's and I was thinking of trying that with his. In your case, maybe it wasn't the cones that had to reburn in, but perhaps it was the capacitors in the crossover network

[hermanv]

...edit...

I'd say loudspeakers require less time than your mocs...and that's if they need to be done at all...As Kex suggested a few minutes should be quite sufficient...the only moving parts are the surround and spider, so once it's compliance has become spec'd, that's pretty much it...You certainly don't want the diaphragm to change, it's rigidity level is a part and parcel of it's performance; any unwanted flexing would bring about distortions.

Hi RL; Cone speakers distort, actually they distort quite a lot. Most cone speakers couple only about 0.5% of their energy into the air so they are amazingly underdamped, they ring and flex and generally misbehave which is one reason so many different models and cone materials exist.

ALL cone speakers have flex in the cone! That's the diaphram you mention. It would be damn nice if they didn't, but no material is stiff enough not to bend at the higher frequencies that a given driver is asked to reproduce. Why would anyone bother to develop a ceramic much less a diamond cone if the cone wasn't flexing?

Paper cones flex a lot, about 2 years ago B&W sent out a DVD showing the resonance peaks in thier midrange driver, there are too many modes to count. Many peaks and valleys develop at different frequencies and excurions. It's this flexing that causes break up and the speaker designer has to decide how far into breakup he will let his design go. Remember it is volume dependant so while a cone might not break up at one level and frequency it will at the same frequency, but at a higher volume.

Cones break in, after many bending motions they flex better and get smoother sounding. It's not that clear if this softening needs to be re-done after a long storage.

Losing flex in the flexible bits is a continously variable process. These bits get gradually stiffer (or maybe looser) over time, it's by no means an all or nothing thing.

[dingus]

Have you ever considered upgrading the crossovers in those old Wharfdales? My father has a pair of WD 70's and I was thinking of trying that with his. In your case, maybe it wasn't the cones that had to reburn in, but perhaps it was the capacitors in the crossover network

i didnt mean to infer that my situation with the Wharfedale's was due to cone break in. it was definately the caps reforming. that was about 18 months ago.

i did replace the caps and internal wiring earlier this summer. it was my first cap job and i didnt really know what i was doing. i ended up getting the cheapest caps out there. at some point i'll replace the cheap caps i put in, with some of good quality.

[jrhymeammo]

Hi RL; Cone speakers distort, actually they distort quite a lot. Most cone speakers couple only about 0.5% of their energy into the air so they are amazingly underdamped, they ring and flex and generally misbehave which is one reason so many different models and cone materials exist.

ALL cone speakers have flex in the cone! That's the diaphram you mention. It would be damn nice if they didn't, but no material is stiff enough not to bend at the higher frequencies that a given driver is asked to reproduce. Why would anyone bother to develop a ceramic much less a diamond cone if the cone wasn't flexing?

Paper cones flex a lot, about 2 years ago B&W sent out a DVD showing the resonance peaks in thier midrange driver, there are too many modes to count. Many peaks and valleys develop at different frequencies and excurions. It's this flexing that causes break up and the speaker designer has to decide how far into breakup he will let his design go. Remember it is volume dependant so while a cone might not break up at one level and frequency it will at the same frequency, but at a higher volume.

Cones break in, after many bending motions they flex better and get smoother sounding. It's not that clear if this softening needs to be re-done after a long storage.

Losing flex in the flexible bits is a continously variable process. These bits get gradually stiffer (or maybe looser) over time, it's by no means an all or nothing thing.

Hi Herman, that was one of the most intriguing posts I've read in awhile. Thank you.
One thing that worries me sometimes is that when I visit some audio stores, they are blasting brand new speakers at extremly high SPL. I asked one of the salespersone if he was aware of it. He informed me that the store just received those speakers yesterday and they were just breaking them in. It was the system comprised of Sonus Faber Amati Anniversario and Classe CA-M400 amp.
I've always thought during the break-in period, it must be played at lower volume for more than 100+ hours, then gradually turn it up over time.

BTW, I thought that was one of the MOST over-priced system I've heard in my life. Turns out they were playing compressed files. Go figure.

[hermanv]

Developing the ability to hear problems in systems, speakers or rooms especially so you can make others understand why what you hear is wrong, is not an easy thing. Not that many salemen have the time or interest, mostly they just parrot what they've been told.

In many showrooms I've been to, the systems could do far better, but they weren't set up right, not that hard to understand if the sales people can't actually hear the problem. I've seen glass display cases in front of speakers, speakers set so that the rears face symetrically into room corners, no attention to hard/soft surfaces etc. Sometimes you see these things in very high end shops.

Learning to hear well is not hard, it requires mainly time and an ability to accept that many things will influence what you hear. After learning these skills for yourself, I believe the quality of the sound from any system will probably increase a lot. This is because many improvements are either free or represent a small proportion of your investment. Of course if you get really good at this, your wallet may desicate.

[daviethek]

Took a couple hunj to break in the Gallo's. Went from underwater sounding to crystal radio earpiece to citizens band to clear. Almost lost patience. If not played for a while, it takes a few hours again.