Speaker Break-in - is this normal?

Spenser Hamilton

Spenser Hamilton

Senior
Sep 12, 2012
653
6
18
SW Ontario
Breaking in a new 18TBW100, I do not recall my Lab 12's making this much noise during the break-in process.

20Hz Sine, 10VAC according to Volt Meter (I know that's not %100 accurate but it's the same way I broke in the Labs)

Not a lot of cone excursion so I doubt it is bottoming out.

There is a block of wood holding the speaker up so that the vents are not blocked, I also tried picking up the speaker to eliminate it being the wood or cardboard vibrating, made no difference in sound.

[video]https://dl.dropboxusercontent.com/u/25226419/Video%2010-25-2013%2C%202%2010%2058%20PM.3gp[/video]
 
Re: Speaker Break-in - is this normal?

Hey Spencer,

Modern large excursion woofers (like the 18TBW100) rely on voice coil cooling vents for a large portion of their power handling numbers. These vents make noise, especially when the woofer is driven nearly an octave below Fs outside of an enclosure. In practical use this noise is masked by the enclosure's acoustic LPF and is significantly below the level of useful audio coming off the cone. Don't worry about it, when you load it into an enclosure you'll be fine.

P.S. Good woofers pay careful attention to suspension aging effects, the break in period of the 18TBW100 is not long and the driver will be stable for many hundreds of hours of large signal use after that. This is another one of those things you get for your money with a better woofer that you don't see on a spec sheet. Unless you need to take stable TS parameters you're best to just stick it in a box and go out and rock.
 
Bennett Prescott said:
Hey Spencer,

Modern large excursion woofers (like the 18TBW100) rely on voice coil cooling vents for a large portion of their power handling numbers. These vents make noise, especially when the woofer is driven nearly an octave below Fs outside of an enclosure. In practical use this noise is masked by the enclosure's acoustic LPF and is significantly below the level of useful audio coming off the cone. Don't worry about it, when you load it into an enclosure you'll be fine.

P.S. Good woofers pay careful attention to suspension aging effects, the break in period of the 18TBW100 is not long and the driver will be stable for many hundreds of hours of large signal use after that. This is another one of those things you get for your money with a better woofer that you don't see on a spec sheet. Unless you need to take stable TS parameters you're best to just stick it in a box and go out and rock.
Click to expand...

Thanks Bennett, that was the kind of answer I was hoping for.

Much appreciated, time to start building!


Sent from my iPhone
 
Re: Speaker Break-in - is this normal?

Spenser Hamilton said:
Breaking in a new 18TBW100, I do not recall my Lab 12's making this much noise during the break-in process.

20Hz Sine, 10VAC according to Volt Meter (I know that's not %100 accurate but it's the same way I broke in the Labs)
Click to expand...
Spenser,

That amount of noise seems unusual to me, my BC18SW115-4 drivers (almost the same specs, but neo magnet) had almost no vent noise at all when breaking them in with 20 Hz driven to Xmax.
I recall being surprised, as they were one of the few speakers I ever heard more fundamental than noise when played open air that low, much less vent/spyder noise than the Lab 12.
Does the speaker make any noise when you push on it by hand?

Art
 
Re: Speaker Break-in - is this normal?

Art Welter said:
Spenser,

That amount of noise seems unusual to me, my BC18SW115-4 drivers (almost the same specs, but neo magnet) had almost no vent noise at all when breaking them in with 20 Hz driven to Xmax.
I recall being surprised, as they were one of the few speakers I ever heard more fundamental than noise when played open air that low, much less vent/spyder noise than the Lab 12.
Does the speaker make any noise when you push on it by hand?

Art
Click to expand...

Pushing the cone out produces no noise. Pushing it in further than about 1/4" makes a rubbing sound. Damn, I don't know if I should send it back :(~:-(~:sad:
 
Re: Speaker Break-in - is this normal?

Spenser Hamilton said:
Pushing the cone out produces no noise. Pushing it in further than about 1/4" makes a rubbing sound. Damn, I don't know if I should send it back :(~:-(~:sad:
Click to expand...
Are pushing with an even pressure all around?

Simply pushing on one side of the cone can "warp" it a bit-enough to cause the voice coil to rub a tad.

I use 4 points (thumb and index finger spread around) to try to apply even pressure.
 
Re: Speaker Break-in - is this normal?

Ivan Beaver said:
Are pushing with an even pressure all around?

Simply pushing on one side of the cone can "warp" it a bit-enough to cause the voice coil to rub a tad.

I use 4 points (thumb and index finger spread around) to try to apply even pressure.
Click to expand...

Yep, both hands, thumb and index spread as wide as possible.
 
Re: Speaker Break-in - is this normal?

Spenser Hamilton said:
Pushing the cone out produces no noise. Pushing it in further than about 1/4" makes a rubbing sound. Damn, I don't know if I should send it back :(~:-(~:sad:
Click to expand...
Unfortunately, sounds like the driver is hosed.
An 18TBW100 has 57mm peak to peak Xlim, you should be able to push it in over an inch without any noise, and the double spider makes it harder to warp than a single spider cone.

One possibility is there is a small piece of glue in the gap which may wear away, hit it with enough juice at 15 Hz to see 28mm peak to peak movement and see what happens.

Years ago I was breaking in an Eminence 4015LF and heard it start "clanking" just over 10 mm peak to peak. The driver was rated for 9mm Xmax, I mistakenly assumed that was peak to peak and the voice coil was hitting the back plate, but Xmax is one way, the driver should have been able to do 18mm peak to peak easily.
After using the driver for a while, and realizing my Xmax mistake, later tested the driver and it worked fine to past 18 mm peak to peak, the glue blob evidently got pulverized.
 
Re: Speaker Break-in - is this normal?

Spenser,

This doesn't sound like a woofer in proper condition. See if the retailer you got it from will take it back, if it has a suspension problem or anything in the gap that's our bad and you shouldn't have to live with it.
 
Top Bottom