On my Basszone test CD, I put 10Hz speaker break in tone. All you really need to do is push the driver back and forth over it's suspension range. You can do this with any frequency, but with frequencies lower than Fs, it is easier to get the woofer to move to high excursions. I picked 10Hz for this tone because it is inaudible. You can hook up the woofer, put the track on repeat, and just let it play without it bothering you.
As far as time goes to break in a woofer, it all depends on the driver. On some Audiobahn woofers, I measured an Fs of 33Hz right out of the box. By simply pushing the driver in and out by hand as far as I could a few times, and then running my finger along the surround to loosen it up, Fs dropped to about 29Hz. After playing the break in tone for an hour, it dropped to 27Hz. Playing it overnight only dropped it about .3Hz.
Many people like to go with 100 hour break in or more, but if you are pushing the woofer to high excursions, 90% of the break in will occur withing the first few minutes to an hour.
The Tempest does not require alot of break-in, it performs like the sims predict right out of the box.
At least this is the case for me because I have a powerful amp that thinks the Tempest is a tweeter.
- I own and recommend your Basszone test CD to everybody
I meet, especially the track five slow frequency sweep. Could you please explain why that sweep starts at 1Hz. rather than 10Hz. or even the more common 20Hz.?
I misread the 1Hz. as 10Hz. when I first played Track 5 at home and I almost had a heart attack when I saw my Tempest driver stroking long distances at 1Hz.
Not only will the track 5 sweep give you a quick estimate of bass frequency response deviations (used with a sound meter) it is the only sweep that is slow enough for audiophiles to wander around their listening room locating room noises while they are happening. Most sweeps are too fast -- you hear objects in the room resonate but the noise often stops before you figure out what was rattling.
Room noises are a major cause of distortion at bass frequencies -- much more audible than harmonic distortion.
Back to break-in:
My Tempest driver took longer to break-in than any other driver that I've used in over 30 years of building speakers.
It took 10 minutes of playing loud bass heavy rap music.
The actual break-in may have taken 30 seconds but I didn't stop to measure until after 10 minutes. The bass was weak at first but efficiency was normal after 10 minutes of use.
It's interesting that Vance Dickason in his latest Speaker Design Cookbook says the primary reason for driver break-in is to be sure the driver is operating properly. The small changes to F/S specs are offsetting and would have a minimal effect on enclosure design.
Tom Nousaine once wrote (on-line) that comparing a new driver with a "broken in" driver is more of a comparison of a driver with a cold voice coil and the same driver with a hot voice coil = measured changes are probably due to voice coil warm-up rather than any permanent change to T/S specs.
Since no two "experts" give the same advice on driver
break-in (making me suspect that no one knows what they are talking about because insufficient data have been collected to reach a conclusion), here's my advice:
Play Sgt. Pepper vinyl record backwards for 999 hours with speakers stacked (one vertical and the other horizontal forming a "T" shape) and connected out of phase while visiting your Mother-in-Law in Bulgaria.
The great thing about audio is that you can say anything about speaker break-in and some people will believe you.