Xmech rather than Xmax (different things unless otherwise stated).
It depends on the driver. A short[ish] throw type can be adapted as GM says. For longer throw designs it's more problematic, because you've got a low-mass driver with a coil, cone, suspension etc. set up for bandwidth, not extreme rigidity under high continuous loads. The travel is usually there to allow minimal compression when you get a short excess of load e.g. a sharp LF dynamic peak; it's not there so the driver can be run off the end-stops for extended periods. 😉 If you push them to those sorts of excursions constantly, you're risking warping the cone, overheating the coil, or some other joyous variation on the theme. As Troels often says 'a blown driver is a misused driver'. They're not all that fragile, but a bit of mechanical sympathy is usually a good idea unless you have very deep pockets and very long arms. 😉
👍 I keep forgetting high Xmax 'FR' driver 'situations' as they didn't exist during my active DIY 'career'. 
That said, 'my' way would still apply if the units are for prosound apps. Even the heavily tweaked RS 40-1354 automotive 'FR' drivers in Buzz's MLTLs are still taking the occasional back plate bouncing/whatever over excursions for 23+ yrs now and still surprising ever more folks how good inexpensive drivers can be made to sound, though sadly doesn't make any DIY converts thanks to the massive on-line ad campaigns 'hawking' ever more modern techno-gizmo offerings.........
That said, 'my' way would still apply if the units are for prosound apps. Even the heavily tweaked RS 40-1354 automotive 'FR' drivers in Buzz's MLTLs are still taking the occasional back plate bouncing/whatever over excursions for 23+ yrs now and still surprising ever more folks how good inexpensive drivers can be made to sound, though sadly doesn't make any DIY converts thanks to the massive on-line ad campaigns 'hawking' ever more modern techno-gizmo offerings.........
I recently bought a few high-Qts car speakers for a test and played 100Hz @ 1W during 12 hours.
Fs went from 93.2Hz to 87.8Hz.
I didn't know the specs of the drivers before getting them.
Edit: I let them rest for a while before measuring again.
Fs went from 93.2Hz to 87.8Hz.
I didn't know the specs of the drivers before getting them.
Edit: I let them rest for a while before measuring again.
Last edited:
I'll never be convinced that driver burn-in is a real thing although it may well be insignificant as one of a thousand variables. A driver's performance will constantly change according to temperature, humidity, atmospheric pressure. To compound the problem, the users perception of sound will change according to the same variables. I'm convinced my speakers sound slightly different on different days.
I can understand how an internal combustion engine with all those moving parts and steel surfaces being subjected to temperatures for -50c to 2,500c in seconds - all that rapid expansion?
Speakers drivers aren't that complicated. With a piece of copper wire, some paper, and a magnet - you can reproduce any sound known to man.
That's why they fascinate me.
I can understand how an internal combustion engine with all those moving parts and steel surfaces being subjected to temperatures for -50c to 2,500c in seconds - all that rapid expansion?
Speakers drivers aren't that complicated. With a piece of copper wire, some paper, and a magnet - you can reproduce any sound known to man.
That's why they fascinate me.
fun fact is that after your 24 hr torture at Fs, Fs may go down a bit, but Vas and Cms will increase.
In my case I got this, wondering if it makes sense. Not arguing against or in favor, just learning.
Fs 93.2 Hz -> 87.8 (Not easy to get this wrong because of the impedance curve)
Qms 9.947 -> 9.181
Qes 3.496 -> 3.295
Qts 2.587 -> 2.425
Vas 4.71 litres -> 4.05
Cms 0.292 mm/N -> 0.251
I'm an old retired heavy duty mechanic. Everything breaks in. That means any abnormal wear, excessive wear or failure
(infant mortality) hasn't occurred and the item meet or exceeds specifications. Some specifications are objective and some are subjective, based on objective, visual and auditory changes. I'm referring to audio gear, BUT ALL thing change from the day they come to life or start their service to the end of their life or duty cycle. There is a beginning, middle, and end. The MIDDLE is the active life/service cycle and hopefully the most productive and the most reliable part of that time.
Can you measure break in? YES you can. The question is do you need to?
BURN-IN is what happens to incandescent bulbs and valves. Even BRAKE pads, shoes, drums and rotors break-in. NOT burn in
things burn up, things burn down, but few things BURN-IN. Tubes and lights are TWO that do. Then there are BURNOUTS and of coarse sideburns. How they got on your face, I got no idea.
Regards
(infant mortality) hasn't occurred and the item meet or exceeds specifications. Some specifications are objective and some are subjective, based on objective, visual and auditory changes. I'm referring to audio gear, BUT ALL thing change from the day they come to life or start their service to the end of their life or duty cycle. There is a beginning, middle, and end. The MIDDLE is the active life/service cycle and hopefully the most productive and the most reliable part of that time.
Can you measure break in? YES you can. The question is do you need to?
BURN-IN is what happens to incandescent bulbs and valves. Even BRAKE pads, shoes, drums and rotors break-in. NOT burn in
things burn up, things burn down, but few things BURN-IN. Tubes and lights are TWO that do. Then there are BURNOUTS and of coarse sideburns. How they got on your face, I got no idea.
Regards
Not on mine, although the hair is bordering on a mullet. Which since I'm 44 technically falls into the 'crimes against humanity' category with execution the only possible solution.
'Burn in'. No idea where that phrase came from, but we see it, and it still doesn't make much sense. Break in -yes. In fact, with some of the old Fostex units, you almost literally had to 'break' them to get them working as intended.
'Burn in'. No idea where that phrase came from, but we see it, and it still doesn't make much sense. Break in -yes. In fact, with some of the old Fostex units, you almost literally had to 'break' them to get them working as intended.
Salutary (depressing) example of the power of marketing vs reality.👍 I keep forgetting high Xmax 'FR' driver 'situations' as they didn't exist during my active DIY 'career'.
I miss the 1354. I've only heard 2pr that made it over here and the performance / £ ratio was ridiculous, even stock. Nearest I ever came across was the Monacor SPH-60X -and then some bright spark changed it a few years ago & it's not been the same driver ever since.
That curve is often known as the bathtub curve, and its middle region is what determines the 'useful lifetime'.
https://en.wikipedia.org/wiki/Bathtub_curve
some pro woofers have a lacquered spider, after some beating it visibly cracks and the cone moves more easely, i can feel the difference by hand on some of my eminence. if i crossover the woofer to high i can clearly hear the difference in breakup from new to used. other times with a low enough xo im not so sure..
for seas woofers without this i have not noticed any difference.
for seas woofers without this i have not noticed any difference.
As one of our members from Canada pushed the first generation Markaudio CHR-70 so hard he almost turmed the cones inside out (an exaggeration, but… dead drivers just the same).
dave
Eek! Forgot to insert link (unfinished, i.e. missing wide span framework 'pallet' base to make it near enough child/pet knock over proof, 'tophat' filled with his huge collection of spare change for mass loading and finished ~ matching wood color grill cum critical damping pads for driver, vent).
Unfortunately he moved hours away (not counting traversing the ~entire East/West Atlanta traffic) before I could take any pictures and long ago now given up asking him for some.
Unfortunately he moved hours away (not counting traversing the ~entire East/West Atlanta traffic) before I could take any pictures and long ago now given up asking him for some.
Back when I was auditioning for Jimmy Buffet's 'God's own drunk', it was Rebel Yell legal moonshine with 'chaser'/mixer to 'taste' when the 'real deal' out of (name deleted to protect the (in)famous guilty) dried up at affordable prices, though guess this might suffice if I ever wanted to reacquaint myself with 'calling for Earl' in the wee-wee hours.