killdozzer
Major Contributor
Break-in? Is this a situation where everyone should first define how they use a word to avoid drawing out swords in vain?After a few weeks it restored to the initial 120hz.
Break-in? Is this a situation where everyone should first define how they use a word to avoid drawing out swords in vain?After a few weeks it restored to the initial 120hz.
My bad, sorry, working two weeks without a day off makes me grouchy...Don, sorry. There is serious plasticity in some driver suspensions. I've seen that most prominently in the anonymous driver I mentioned above. The effect of changing resonance frequency over time--rapidly to lower fs under stress, slowly creeping back up, within weeks(!), is a matter of fact with that particular driver.
Usually I don't care. Reason is, that with a shift of fs other parameters change accordingly, so that the Thiele/Small alignment, hence the response doesn't change with any significance.
But here the shift was so crass, that the driver couldn't be used as originally intended. I didn't want to play as loud as the driver was designed for. At least not all the time--110dB anybody?
Another aspect is a shift in fs due to excursion. Usually the suspension stiffens with higher excursion. But (some) SEAS drivers lower their fs with higher excursion, as was confirmed by a SEAS technician. See https://hificompass.com/en/reviews/seas-excel-6-w18nx003-e0096-08-midwoofer-review, keyword "Claus Futtrup". Maybe You take that as another hint for the possibility, that my observation wasn't supersticious.
I'm quite aware that this discussion is focused on off-the-shelve hifi-speakers. I never claim a need for breaking-in these. Even if there was, the usual suspects wouldn't notice anyway. The break-in is just an excuse for common cognitive dissonance, considering an anyway unreasonable purchase.
My bad, sorry, working two weeks without ...
Have a look at Amir’s measurements of the Neumann KH80 speakers a while back It took three attempts with the final one clearly showing the effect of ambient temperature on the woofer. However, I would not call this break-in.Do drivers break in?
Yea sure they do, to some extent.
To my experience warm up is much more real.
I have measured TS/P's in many speakers. If they are cold they are stiff.
Bring the drivers in from the cold and let them warm up in the warm lab over night.
Hook the driver up to the test software and power amplifier and run the test sweep a few times and watch how the TS/P's shift with warm up.
The manufacturers always do a warm up period prior to testing TS/P's for real.
I do not believe in "Small" TS/P testing. Test with the same voltage that the speakers will be operated with at or near 85 dB's.
Just my approach.
Thanks DT
I also wanted to know and got involved in several debates like this one. They all ended in: there's theoretical break-in only in first minute-two of playing and sometimes not even that if a driver is tested at loud levels in the factory. There's nothing an end consumer should do or take notice of in order to "properly" break in drivers. No audible SQ is to be achieved through this break-in as materials used are chosen to do their job for a long time and will do so. Gradual change over decades is not something you notice or can affect. What needs to happen to drivers at those first few moments will happen regardless of your "break-in ritual".Do drivers break in?
Yea sure they do, to some extent.
To my experience warm up is much more real.
I have measured TS/P's in many speakers. If they are cold they are stiff.
Bring the drivers in from the cold and let them warm up in the warm lab over night.
Hook the driver up to the test software and power amplifier and run the test sweep a few times and watch how the TS/P's shift with warm up.
The manufacturers always do a warm up period prior to testing TS/P's for real.
I do not believe in "Small" TS/P testing. Test with the same voltage that the speakers will be operated with at or near 85 dB's.
Just my approach.
Thanks DT
As nearly everything in audio-talk this is best speculation, or to put it from my perspective: bold bumbledom. The only instrument the proponents regularly have is their superstitious golden ears and a lot of imagination--and a victim to talk to.... regardless of your "break-in ritual".
that is warm up, not break in, driver or any material behaves differently at different temperature, both the movement induced or environmental.Do drivers break in?
Yea sure they do, to some extent.
To my experience warm up is much more real.
I have measured TS/P's in many speakers. If they are cold they are stiff.
Bring the drivers in from the cold and let them warm up in the warm lab over night.
Hook the driver up to the test software and power amplifier and run the test sweep a few times and watch how the TS/P's shift with warm up.
The manufacturers always do a warm up period prior to testing TS/P's for real.
I do not believe in "Small" TS/P testing. Test with the same voltage that the speakers will be operated with at or near 85 dB's.
Just my approach.
Thanks DT
Not sure what you find 'bumledom' about it. Until we have reliable data to show otherwise, same drivers don't end up performing differently just because you break them in differently. You take the same model of speakers from two different owners back to the testing ground and they sound the same (unless damaged).As nearly everything in audio-talk this is best speculation, or to put it from my perspective: bold bumbledom. The only instrument the proponents regularly have is their superstitious golden ears and a lot of imagination--and a victim to talk to.
The only thing I ever had 'breaking in' was a pro p/a bass driver. But it very soon recovered from that breakage. Driven very hard, means 30W cont/ @below resonance frequency dropped the resonance frequency from 90Hz to 70Hz. But within a few days it was coming back and kept rising over the next weeks. Good/bad, I don't know. Let's speculate.
Hey, check this one out....
Here's a prosound 15" that sat on a shelf for a while.... i'm in the process of loosening it back up in a bass-reflex box.
Left is the Impedance graph of a cold start in the morning..
Middle is after 5-6 hours of running hard at 10Hz during the day.
Right is about 2 hours after running hard, all cooled down.
This pattern has been repeating itself over multiple days, but with positive signs of developing convergence.
I guess it needs a lot of warmup to break-in; or maybe needs complete break-in, so it doesn't need warmup?? ha ha....i dunno
View attachment 243981
You can see the DATS logo in the impedance plots, so I guess you mean how far from the speaker terminals do I measure...how did you measure the impedance ?. if you use a resistor and measure the diffrence between resistor keep in mind thats if you have a long long thin cable. also if the resistor get warm it change resistence. many high power resistors have 10% .
The sense resistor, which must be non-inductive, is used to measure the current flowing into the load, which will be (Vleft - Vright)/Rsense. The sense resistor should have a power rating sufficient to cope with a short circuit load and have a low temperature coefficient. The voltage across the load is Vright, so the impedance is nominally voltage/current = Rsense*Vright/(Vleft - Vright). Note that prior to completing the calibration process the accuracy of impedance measurements is only as good as the accuracy of the value entered for the sense resistor.
Hi, well again, i use DATS....so not REW. There is no decision needed concerning what resistor to use, like in REW.I mean which resistor you use. in this is explain how to measure. he call it sense resistor and he use 47 ohms
so which resistor you use ?. I think your diffrences are so much. what FR changes you get ?. I think best is use a 0.5 ohm resistor or look at some frequencies with a mulitmeter amp. for today more senible systems you need not so large resistors as told in the old hifi science
Hi, well again, i use DATS....so not REW. There is no decision needed concerning what resistor to use, like in REW.
Mine is DATS version 2, https://www.daytonaudio.com/product/1051/dats-v2-dayton-audio-test-system-discontinued
and has been supplanted by DATS version 3. https://www.parts-express.com/Dayto...udio-Component-Test-System-390-807?quantity=1
But it works just fine, and the only resistor in the equation, is one that is used to calibrate the USB device..
Bottom line; the changing impedance plots are accurate,