Break-in methods for new drivers?

[Soldermizer]

I'm looking for advice on how to "break-in" new drivers. I am aware that the T/S params can change at least slightly. This would seem to be important for the purist, who wishes to have the true specs of his drivers before he designs the enclosure for it. Do I just mount them on a box or panel and exercise them for X hours? Is it really that important? While I have been known to purchase (slighly) more expensive drivers, the present victims under consideration are the horrors I bought back in the spring for a future line array project

4.5 Inch 10W 8 Ohm Full Range Pincushion Speaker | XF-119-208 (XF119208) | Distributed By MCM

Why "pincushion"? I guess you guys can "needle" me for my miserly purchases

 

[AndrewT]

A volt or two @ lowish frequency, maybe 10Hz to 30Hz for 48hours should exercise the surround and spider.

I have checked a 15" & an 18" before and after 24hours of exercise. The Fr does change considerably.
It also reverts nearly back to factory state if left on the shelf for a long time.

I remember my AE1's changing in the LF over a period of many weeks.
Maybe because I didn't exercise them.

If I'm going to do T/S parameter measurements, I will do the 48hours run in every time.

 

[JMFahey]

^^^^^^^^^^^^^^^^ that .
Don't know how people can even argue against , speakers change so much after exercise.

 

[Soldermizer]

I'm not aware of any debate on speakers, it is however news to me that they revert to spec if left unused. Now, off to break in my new interconnects (joking!) :*) I am in process of applying Danmar Varnish to the collection of $2.24/each drivers (why not? I have it on hand); if it works for expensive drivers it will...at least make the home smell like pine oil for the duration

 

[sofaspud]

It might be worthwhile to read Tom Nousaine's urban legend article in The Audio Critic #29 if interested in another perspective.

 

[chrisb]

pincushion would refer to the outer shape of the stamped metal basket frame

 

[planet10]

I am aware that the T/S params can change at least slightly. This would seem to be important for the purist, who wishes to have the true specs of his drivers before he designs the enclosure for it.

Do be mindful that T/S are not scalars, but curves. The numbers you get can be equally valid and quite different depending on the kit you use to measure them. Largely differenses due to drive level. These differences mostly balance out so that alignments are still OK.

T/S also change with the weather (mostly the temp & the air pressure).

I have rarely had any issues using the factory data to design boxes. I use T/S to match drivers into pairs, unit-to-unit variance can be +/- 10% (best manufactures) near +/- 20% for good manufacturers, and worse that that for lesser ones. I have measured many 1,000 of drivers.

We only build boxes that are fairly tolerent of T/S changes.

That said, all drivers go onto a break-in bench where low level FM is played thru them for at least 200-300 hrs before i measure them.

dave

 

[Bigun]

...
It also reverts nearly back to factory state if left on the shelf for a long time.

I remember my AE1's changing in the LF over a period of many weeks.
Maybe because I didn't exercise them.

I built some Alpair 10.3 Pencil's for a friend. He says they need a short break-in if he doesn't play them for a couple of weeks.

 

[killmister]

Hello.

To break in speaker, I use a frequency 5hz for 24 hours and 25 Hz for at least 48 more hours. I put maximum power before hearing any mechanical noise.For example, here are the differences I got:

FE103 SOL 103 hz -> 94 hz
FE127e (nos) 94 Hz -> 73 Hz
FF125 (nos) 85 Hz -> 75 Hz

Despite this, all the speakers are above the specifications.

I did not measured other parameters.

 

[picowallspeaker]

H I use a frequency 5hz for 24 hours and 25 Hz for at least 48 more hours.
FE103 SOL 103 hz -> 94 hz
FE127e (nos) 94 Hz -> 73 Hz
FF125 (nos) 85 Hz -> 75 Hz

Those speakers aren't going to reproduce 25 Hz, go figure 5 Hz

 

[AndrewT]

They will reproduce 5Hz, but the SPL will be low.

 

[picowallspeaker]

Let's talk about 25 Hz which is a fairly low freq. for a subwoofer
Then you put 1 Watt; then you see the membrane going up and down within the limits.
That's because you're using the device in its working band.

 

[AndrewT]

And you will see it moving at 1Hz and 5Hz and 10Hz.
At each frequency the driver is producing an output.
Will you see the driver moving @ 25Hz, or will it appear as a blur?
Either way it will produce an output.

 

[picowallspeaker]

Many members on this forum that use software for making boxes would tell you that you're talking nonsense !
Transducers -yes, but in their working band

 

[AndrewT]

Are you saying that seeing a driver moving with applied signal is equivalent to producing no output?

Surely no other Members here would agree with you.
Even if they used simulation software, I still can't see how they could agree there is no output.

If the driver is moving there is output.

 

[killmister]

Those speakers aren't going to reproduce 25 Hz, go figure 5 Hz

I use low frequency for maximum excursion at low power. I know that these little speaker are not subwoofer ! We are talking about break-in? No ?
The break-in is useful to soften supensions and spider, we do not care 25 hz transducer capability !

 

[picowallspeaker]

Transducers -yes, but in their working band

And with complex ( = musical) signal

 

[JMFahey]

We are talking edge and suspension/spider softening here, not flat frequency response.

Max excursion without damage?: fine, will work faster than a lighter drive.

SPL @ 5Hz , 25Hz, whatever?
Who cares?

We are talking unmounted speakers by the way ... although a ported cabinet usually also counts as "unmounted" at such low frequencies.

 

[killmister]

SPL @ 5Hz , 25Hz, whatever?
Who cares?

5 hz is to get the maximum excursion easily and 25 hz gives more movement /second without hearing too much noise.

 

[picowallspeaker]

Frequency Range ( -10 dB ): 90 ~ 12200 Hz
Xmax 1 mm
Voice Coil Diameter 14 mm / 0.55"