Tires break in, engines break in, speakers break in, clothes break in. It’s all real and I don’t get why people think speakers are made of some magical material that doesn’t need a little movement to settle down. Love the straightforward answer Paul

Break-in as opposed to wear are two different things, which the asker has conflated in their question. Break-in occurs fairly quickly as parts are first put into use, to which then normal wear (which is much slower) is predominant. Take a new car - you are advised to drive gently/moderately for a few hundred miles until the rings get settled in with the cylinders in the engine, and then after that period drive it like you want to; wear will happen gradually and at a slower pace than the initial break-in period.

Great way to dumb it down for us newbies thank you!

LoL, that's me in our electrical test area at my job Paul. I always take my glasses off. "Good thing that's not on. That could have been a shower of sparks." We have a similar sense of humor. I enjoy the videos. Useful information on the speakers. Keep them unrehearsed and laid back. That's what we want !! Great stuff.

Paul's answer to these questions are the best explanation about speaker break in I've ever heard and the way the questions were presented were equally as impressive. I am now a believer.

thanks for taking up my question Paul!! I never thought of break in in terms of the actual woofer casing and the crossover components. I was only thinking in terms of the cone itself. So your explanation has been an eye opener, given the email indicated that the more I read about this stuff the less I know. But to qualify why I asked those questions, as some comments seem to indicate it's a moot discussion - yes, I understand all moving things "wear/break-in" into their "comfort zone. Break can be "snake-oil" in terms of subjective perceptions of "sound quality" and "enjoyment", but I know it is also an objective fact in terms of physics. But I'm not an engineer, I'm a social science scholar, so I was just thinking critically about some aspects. Paul's answers have not only confirmed something I already believed, but has helped me understand better the way the system works together. Thank you!

What a great answer and explanation! Thank you!

Paul: Excellent explanation regarding speaker break in. Really makes the process easy to understand. Glad you confirmed that speaker break in is not a myth, as some believe. Good job!

Awesome explanation, thank you.

Explain simple into the point, thank you!

You’ve so much patience Paul!

Great answer!

When I worked at Sound Company in San Diego (now defunct), certain high-dollar Thiel loudspeakers required more than 100 hours of break-in time. A difficult task...running loudspeakers for 100 hours where they are not intruding on your life in general.

I love your videos, so honest.

In the 90s I put a subwoofer in my car. Rockford Fosgate audiophile 12 in a ported box. At first if you pressed the cone it felt stiff. But after a week or so it loosened up and with that the bass got louder,faster,and hit harder. Overall the sound improved and ever since I know break in is real.

I bought a pair of Elac Adante's several years ago and It took the a long time to settle in but one they did the sound got very smooth once I got the toe in right. I learned not to fuss to much with placement and room treatments until they were well broken in because you were just going to have to do it all over again. I have my power amps on top of a 15" tall record cabinet that sits against the front wall with the speakers a good 2 ft in front of them (about 3ft from the back wall. The equi[ment sits on top of a 3" high record cabinet off the the side about 6 ft out from that front wall. I had the preamp, PSA Directstream DAC, and trnsport staceked up next to the turntable that sat on it's own 3" think maple cutting board. I needed more room for records and CD's so i bought a cheap TT stand off amazon that had a welded steel frame and MDF shelves. The TT sits on the top shelf and it's 3" cutting board so it is 4-5" higher than it used to be, this is all right next to the large record cabinet so it's about 16" further out from that front wall. I was now hearing a harsh dlare from the system and I traced to to the mids and highs (coincident mid/tweeter) reflecting off the smooth TT cover. I solved that by storing my Sennheiser HD600's on top of that shiny TT cover, that is just enough to break up that reflection point. Also that welded steel rac (when weighted doen with records and CD's sounds much better that the 3/4" oak recoord cabinet did

Paul, your such a mentor… should I live in America I’d be your protégé.. my dad knew Tim de paravinchi and I had the pleasure of meeting him once. He still has one of my amplifiers, however I know not who to ask about it. It’s an honour to let it go to be frank. Top man

The fact is, and I'm saying this from the perspective of someone who has designed and built speakers for decades, that break-in isn't just real, but has to be taken into account measuring Thiele/Small parameters. The mechanical properties of a dynamic driver change so much due to break-in that it's a mistake to measure a woofer new out of the box and do calculations such as enclosure volume, sealed vs ported design and port frequency, let alone transmission line, horn length etc. The standard procedure is to run the drivers in free air for 24-48 hours, let them cool off for an hour (voice coils expand with heat which in turn affects electrical properties) before measuring. Few manufacturers will break in components prior to shipping, so it's normal to hear improvement in the first few or hundred hours (depending on size, design, suspension, room temperature etc.). These are mechanical devices, clueless as to how anyone could doubt burn-in is a real-life phenomenon.

Caps mechanical? Erm not really. A driver is.. a cap is a passive item.

What is the difference in sound when the speaker eventually does break in? What is actually happening is your ears get more attuned to the speakers after a few weeks. So it is your brain/ear combo that is actually making the sound (better.) Nothing to do with the speakers. And what is 'better' anyway?

I replaced the surrounds for my dual 12 M&K subwoofer and definitely it was a bit stiff. The replacement surround is thicker than the original also. I gradually increased volume over a couple of weeks. I then played bass heavy music to really get the subwoofers moving and definitely it softened up the suspension. I would still say there is a difference still. The original M&K had more bass at lower volume and definitely had a softer suspension due to the thinner surround. The drawback though is that over time the surround starts to deteriorate and eventually fall apart. The new surround is much thicker and stronger and should last longer. Sounds better but has to be at higher volume.

I had a break in experience myself: I sold the speakers which were playing for months at our shop constantly for 12 hours a day so i knew their sound..The next day i receive exactly the same model, but new unopened, and I connected it to the same setup and played the same songs. I've noticed that the sound was not as good as the previous breaked in speakers...The sound was somewhat muddy and not so bright and clean

I don’t actively listen for (nor do I especially believe) that an extended time is needed for break-in; the only time I actually notice some change in performance after an indeterminant amount of time is with some speakers and cartridges I’ve bought new - maybe tubes, IDK. It’s usually enough of a transition to make me stop what I’m doing and think “Hmm - what just happened?”. My Buchardt S400 mki’s seem to have changed about 150 hours in, and my cartridges 20-50 hours - it’s that feeling that just something just came together. I didn’t have that feeling with my mkii’s. Denafrips runs their products for about 100 hours (so they say) so break-in has already been achieved when they show up at your door.

I had the surrounds replaced on my 30yr old HiFi bookshelves as they had cracked and perished. There was a few week break in period. Interestingly I bought some Wharfedale speakers for my home theatre. I detected no break in sound change. Maybe it was done during manufacture.

I've seen speaker manufacturers recommend up to 200 hours, I'm sure that there are some happy people out there with their 'open box speakers that someone else didn't have the patience to break in properly.

Well when I first got my paradigms 800F, I was very disappointed in the way they sounded. The dealer suggested breaking them in at moderate volume for 40 hours or so. So I stopped listening to them and whenever we were out of the house, I would crank the volume and play whatever for hours. Didn't take long to hit 40 hours. They sounded very different and much better. It's possible the integrated needed to be broken in, but a solid state amp seems less likely that it would be affected by usage, compared to paper/glue/rubber moving constantly.

My own experience, I bought old new stock speakers, plugged them in, sounded flat (very limited bass). Listening to those speakers for 2-3 weeks, not quite happy. Anyway, I then decided to try a tone generator, just to test if the speakers could play at least 20Hz-16KHz (hearable sound). Well, it didn't play anything bellow 100Hz, so I added volume and worked the frequency up and down from 0Hz to 100Hz and little by little the speakers (woofers) got better and better to a point the speakers got ''alive''. Full range, as specified. So my thinking is, if there are moving parts and they are supposed to move, a break in is sometimes even necessary.

Oh dear me. Electronics, which are not mechanical, don't need a break in period. They do however normally get subjected to a "burn-in" period; this is typically used to allow any substandard parts to fail and therefore can be changed either on a component level, or a complete remanufacture of the PCB, so to speak. Again, Electronic components do not need a break-in period, they are typically at full operating specification straight from the factory.

So right, I found my harsh speakers suddenly becoming sweet after some two weeks, though this is not apparent in Home Theater use, and can be felt only while playing music, especially in pure music mode and at really low or really high db levels. I have one more doubt, will Klipsch speakers be better if we change crossover from the original two way to 3 way.

Those glasses just disappeared forever😁 Yes, I just spent 2 months breaking in my new front stage speakers in my car, just sitting in the garage and tuning the eqs. The sound changed quite remarkably, as I suspected it would. Now after the break in period, I can finalize the system. Many years ago they tough me to do a 24 hour pink noise break in, but I don't think so any more, spend a few months listening to you favourite music rather, it sounds way better🙈

Hello paul! Can I block my speakers bass reflex holes? What would be the drawbacks and advanteges?

Most manufacturers provide expected tsl parameters for drivers after breakin. So your crossovers+drivers may sound off initially till evrything settles in.

Speaker break-in is absolutely a thing👌 Oh trust me😎

again, great content- I can spend hours on this channel.

3 months ago i bought some used Thiel's. They were already broken in but guess what. I needed a view weeks to get used to the new sound they made and that came without my notice. I noticed it only because i switched back to my old speakers and they didn't sound that great anymore. I still dont believe that speakers need some breaking in time. Your ears need that for sure.

I bought a speaker yesterday and straight out the box the speaker sounded flat and stupid and I regretted buying them but as i played them especially after i run them through some low frequency tests and after couple hours of playing bass boosted music the speaker sound quality got better and i started hearing deeper sounds..when i just got it i even used my flash to see how much the speaker moves and it was stiff and I wondered how was that possible for a speaker to be cranked all the way up playing loud and you see no movement from the speaker but now its moving a bit..might need to run more Low frequency tests

This is an easy one to test. Pick out some test signals that you are going to use, and use a very good recording setup to record the sound of a new speaker before break-in. Then run it through the break-in process and then re-record it using the original setup and original signal. You will now be able to compare the two recordings side by side and be able to both measure and hear the effects of break-in.

Nicely Done. Is there a life expectancy for a speaker. Can we expect any given speaker to last 15 - 30 years. I'll assume all parts might function but not to it's fullest as years go on. What are the usual things to go bad? Thanks

I bought some new PMC speakers, and they sounded awful when first played. Many people still say that speaker break in is a myth, but some manufacturers such as PMC explicitly mention it in the manuals. I assume it was the cone material breaking in, apparently not. I am sure you know about work hardening, where mechanical deformation leads to a change in the structure of a metal at the atomic level.

Great explanation by Paul, one of his best. I would think though that manufacturers of somewhat expensive audio equipment, would want to do a lot of the burn-in or break-in themselves (maybe not the "full" amount of required break-in, but a substantial amount of it). As Paul indicates, this would cost more to the manufacturer. However, it would probably result in fewer customer returns and fewer bad or "unimpressed" customer reviews.

Back in the '80s I heard a pair of Maggie MGIIIs. I thought the sound was magic and ordered a pair on the spot. When they arrived, they sounded so bad I considered returning them, but since that involved shipping them to another state, I persevered and tried moving them around the room. After a couple of weeks I realised they sounded great. I'm not even sure if that happened all at once or slowly, but happened it did.

I barely noticed break in on my stereo speakers, mostly low end. A cheap pair of bluetooth iem had extremely noticeable changes, so much so I went back and re-edited a review to say they were indeed worth the $10 on sale if you need some lawn mowing iems.

Asking Paul about audio myths is like asking a guy in a bigfoot costume if bigfoot is real.

Along with that, how about when you turn on your stereo how long do you wait until you crank it up if at all?

However with the latter, Surround & Spider, over time (a very long time) these can (as the person asking this question alludes to) breakdown and become 'less stiff' than the original Designed specifications and thereby cause the speaker to not be playing as good / accurate as it had been for many many years. Determining this effect and to what degree this has taken place is nearly impossible... for the simple reason that it is occurring so gradual over such a long time that you the Listener will simply become accustomed to the ever so gradually changing sound and therefore never know that it is occurring (which is sort of a good thing, right 😉).

It's the capaciters and the flow of the drivers.

I wonder at what point PS Audio voices/ tweaks their speakers for final production? Before or after the break in period. Does anyone know?

I just wish manufacturers would indicate how much time the speaker went through testing at the factory.

Cool

Its like getting a new hip. You need to do exercises to get the socket and new hip takes eachothers form before you can walk comfortly. ,😅

❤❤❤yes, my dynaudio speakers took 500 hours to me right..

I feel like my razer headphone got worn in and sound better but I have zero way of proving it i may have just not had hq stuff to listen to when i first got them. Also the headphones are not really high end so there's that.

You can test a brand new speaker out of the box and a speaker that’s been “broken in” and the actual data and measurements are negligible.

In support of Paul here's a deep technicial dive into speaker break in. Measuring Woofer Break-In: kzfaq.info/get/bejne/jqp8Z8KFrri4pWg.html

"capacitors are mechanical devices" is simply *not* true! They *are* passive electronic components.

I found its burn out the oxygen in the wire and the voice coil former and stretch the spider

Argue this with Alan Shaw of Harbeth!

Capacitors are MECHANICAL devices? Aren't they electrical / chemical?

Anything mechanical in nature from engine systems to loudspeakers to more or less degree, It all has a wear in period. Anyone whos purchased a brand new atv or dirt bike from a dealer, or bothered to ask while buying a new car, has likely been informed NOT to push a brand new engine hard until "x amount" of gallons of gas or x amount of miles have been driven. You can genuinely straight up damage the cam's and piston housings in the heads if you push an IC engine too hard too soon. Machines have to wear into their spec'd performance, it doesnt matter what kind of machine it is, and a loudspeaker is a good example of a linear excursion motor rather then centrifugal excursion motor like a DC electromagnetic motor or something. It's still a motor, it still functions hrough mechanical excursion. While im at it, ill go ahead and mention that capacitor heat forming is a very real process, that we also like to call "burn in" and is a very understood process. Capacitors perform differently once exposed to voltage and a bit of heat and they (especially electrolytics) are designed to form into their spec'd values and fill the microscopic conductor pitting inside the dielectric evenly, and this is why they sound different new. If we were to make brand new electro caps at their rated values, they would burn in and settle outside of spec after forming to their conductor pitting. The ONLY way to form a capacitor is to pass signal through it and generate a small amount f heat for an extended period. This usually isnt done outside absurdly high end audio products before selling because it would be a very time consuming and costly process just to do something an end consumer will do on their own anyway. It doesn't matter what way you slice it, burn in is real. Go by a brand new copy of ANY product you have owned for a while with moving parts or electrolytic capacitors in it, thats still being made and use it. ANY product, electronic or otherwise, doesnt matter, and tell me it feels and performs the same to use as your worn in product, if you do, you are lying to me. It may not be better, but it will absolutely 100% feel different. There is nothing sold on earth with moving parts, or electrolytic capacitors, that doesnt go through some kind of wearing/burning in process. Doesn't exist. Hell, most things even without caps and moving parts still wear in too. Even a well used wooden soup spoon feels different to use then a brand new one, and i prefer it 10 fold to a brand new one... Idc what Joe-Gaming-Chair has to say about it. Whether its electronic burn in, or physical break in causing operational parameters to change, or wear and tear causing something to act differently then when it was new, it's not just real, its unavoidable, and it applies to basically every product that exists. If you think your brand new loudspeakers will still sound the same 30 days into using them, you are sorely mistaken. If you think your power amp you bought last summer still sounds the same as new. An a/b with a new unit will show you that you are mistaken in your assumption.

How often does Paul have to answer this question... let's have a poll. 😏

I never heard of breaknin, but after 1 year+ I can tell you, its real

Speaker break in can be compare to the baseball catchers glove

Barrels also break in.

Subsonic break in is possible. It can be done silently

My clock radio is getting louder as I break the speaker in

If you believe that audio equipment needs to be "broken in", your brain is broken. If you perceive a difference, it is because You have Become Accustomed to the sound of a component, Not because it has changed in any way.

The real problems come when the suspension starts deteriorating. Then they break out.

Actually there exists three distinct types of "break-in" for a speaker. As Paul mentioned, one kind of "break-in" is electrical which includes everything electrical including cross-overs, wires, L-pads, voice coils, etc and of course this is called "burn-in". Another kind is mechanical in nature and pertains to any moving parts e.g. the speaker driver's moving mechanisms, i.e. the voice coils, suspension systems, etc. and this type of "break-in" is actually called mechanical "break-in". The third type of "break-in" is also mechanical in nature but few are aware of it and even fewer understand it. But this type of break-in has to do with mechanical supposedly stationary objects that hopefully do not move when in operation. This type is called "settling-in" much like a dwelling structure placed on top of a foundation. Or perhaps a component placed on a shelf, or a speaker placed on the floor. And just as a house and/or its foundation never fully settles in, the same potential exists with everything related to our playback systems. BTW, this settling-in type of break-in comes to us in the form more commonly known as vibration mgmt. For which there exists two primary methodologies: One is vibration isolation and the other is resonant energy transfer and one is far superior to the other. But the main thing to note here is that it's against the laws of nature to entirely isolate any object from all sources of vibrations simultaneously. Can't be done. If complete isolation were possible it would occur in a moment in time and without any time needed to "settle-in". And of course achieving a 100% transfer rate of all unwanted vibrations is also impossible. This implies that we're all dealing with a hybrid of the two diametrically opposed methodologies. Which in turn implies we're all dealing with forms of settling-in over variable periods of time. All the above would also apply to turntables and CD players too since they too have electrical components, stationary disparate objects like a TT placed on a shelf, and moving parts when in operation, e.g. the platter, tonearm, motors, CD transport / drives, etc. Regardless, these are the 3 types of "break-in" every last speaker must go thru before it's able to perform at its absolute optimal potential.

Of course break-in of components is real. Where however I disagree with you Paul is you claiming that caps, once burned in, remain burned in. I would agree that is true in cases where they regularly see current draw. We own vacation home in BigSky, which for perspective is at 8450’ elevation. The climate is therefore quite low humidity year round, hvac is in-floor hydronic the only ‘forced air’ is from an HRV system that is set @ 5 cfm/100sq ft, as well as ceiling fans. We visit on average 4-5 times annually, my 2 kids will visit another 3-4 times when we are not there. In all, I’d estimate 75-80 calendar days annually, balance of time it is vacant. Home has a very nice system in living room as well as in my library-office. The living room has dynamic 3-way speakers fed by vacuum tube pre & amps, library has Quad ESL’s fed by vacuum tube pre and mosfet single ended amps. When home has been unoccupied for 6-8 weeks, heat is kept @62F minimum, I turn on the equipment, allowing typically 45-60 min warmup before playing music, the sound will be tight and constrained for at least an hour. By day 2, it will be noticeably more open and lively in both system. I will say the system in my library sounds less constrained initially than the living room. Is that due to the esl’s not having butyl surrounds or is it mosfets are more tolerant of dormancy than vacuum tubes? The point is both systems require “break-in” even though every component in system is at least 5 years old, some like the esl’s and Pass Aleph 1 more than 30 years old, and many, many hours of current running through them. The fact is when sitting for weeks on end w/o any current, components settle on molecular level and need “activation” to return to there brilliant best.

Everyone regardless if they 'believe' or not will Break-In their equipment -- Unless they leave it in the box and don't use it. Point being... Moot discussion

Speaker break-in may occur during the first hour or two but it is unlikely to have any audible effect. A woofer natural resonant frequency may drop by 2-3 Hz after a short initial use, but this effect is audibly trivial.

If “break in” exists, why is it that the product/sound always gets better? Why doesn’t it ever get worse? Manufacturers can (and do) design products for post-break in performance? 🤔

Woofer/subwoofer and midbass need break in.

Capacitor break in? No. Capacitors mechanical? Double no. A capacitor is nothing more than a gap: a break in the electrical pathways with "plates" on either end. When positive voltage is applied on one of the plates, it builds up a positive charge and the other gains a negative charge. Once the charge saturates one plate, nothing more happens, but when voltage is reversed (or at least brought to a lower potential difference with the positive plate), the capacitor discharges, keeping the potential difference the same for as long as possible (which isn't very long because capacitors discharge quickly). And this can happen from the negative plate as well, but in reverse. Saying that a capacitor is mechanical seems to imply you don't understand what they are or how they function. A switch is mechanical because it requires a mechanical force. A capacitor is a passive component, and does not have any mechanical element to it. And to answer capacitor break in...if a capacitor needed to be broken in, computers would simply fail to operate correctly after the break-in period. See, computers use billions of capacitors in their daily routine: in their DRAM (dynamic random access memory). Every single bit of memory your computer has is literally a capacitor. The capacitor needs to be refreshed every so often to keep the value correct in memory. A break in period for capacitors would imply that capacitor's spec would change; otherwise, a broken in capacitor would behave identically to a brand new capacitor. With the speed of modern DRAM (around 2 microseconds on average), even a slight change to a capacitors discharge rate or capacitance value would render that bit of RAM dead, and since most consumer based computers do not include ECC (error checking and correction), your computer would access that byte of RAM, it would fail, and error out. And programs are constantly cached to the hard drive and reloaded in different segments of RAM, so, in very short order, your computer would simply stop functioning and require a reboot. Over and over again. Of course, this doesn't happen and most RAM comes with a lifetime warranty as well, not something that a company would offer if even a handful of "broken in capacitors" would render useless. And that's not counting the dozens needed mitigate voltage drains (bypass capacitors) and keep the system running.

You said capacitors are mechanical of course they're not they are electrical. You can damage the driver spider quite quickly if you play a constant tone so never play a constant tone at volume

My wife is still breaking me in.

I just saw a teardown/repair video of an older PS Audio power plant & was impressed with its build & output signal quality. The unit’s PCB even survived a ropey desoldering attempt. kzfaq.info/get/bejne/r-CIjap2meCmYZs.html

you people really believe this break in doesnt not make a different in sound

so...play music first whatta great tip and that was not meant ugly

You know I understand what you're saying because I have dealt with audio before but next time you talk about speakers maybe have a speaker in front of you so we can see what you're talking about and you can point out the actual thing. People like a visual.

The only guys that think that equipment break in is a delusion.....are at AVS Forums, where they were just fine and dandy with their original Apple IPod earbuds 20 years ago...

Complete confirmation bias. The number of people who believe that the speaker has "broken in" or "burned in" is hilarious - nope, you've just got used to the sound of a new pair of speakers! Give them an hour or two in their setting to make sure they're at room temperature, play music for a couple of minutes to check everything is connected correctly, and that's it. Next up, let's all head to RuSsAnDreWs where they offer to burn in your new KimBeR cables for you (yes, even your digital cables!!) ... all for a modest fee, of course.

The main issue with this “debate” are the vocal minorities: “I absolutely hated this product but after 300 hours of burn-in & listening it’s the best thing I’ve ever heard”. Most of the time when people say burn in isn’t a thing that’s what they have in mind. I think/hope anyway. I’m sure there are exceptions but “this speaker was horrible but after burn in is the best thing ever” is a preposterous claim almost every time it is made. But it’s equally as preposterous and requires an almost superhuman lack of thought to claim speakers don’t burn in. It’s basic common sense unless you don’t know what the suspension components are made out of.

I suspect listeners break in, too.

I don't think you have the myth right. The myth is about whether a special break in method is required not whether speakers eventually break in or not. No speaker needs to have a special break in method done, just play your music, movies, whatever and the speakers will be fine as they break in over time.

I like your videos, but I'm calling you out. Capacitors aren't mechanical in the slightest, and they don't break in; if anything, in the case of the electrolytic caps, they naturally dry out and lose capacity in a linear fashion, and somewhere along that line you're like "yup, that's it, broke it in". Film caps are equivalent to having two metal plates with a sheet of plastic inbetween; they do not change characteristics, because they are entirely solid and static objects, that naturally don't degrade appreciatively; you can blow holes in the film though and degrade it with too high voltage. Your line about energy passing through them, to form properly, to do what capacitors do over time, to sound better, is completely bogus; the only change over time, assuming you don't overvolt damage the film caps, is the linear degradation of the electrolytics. The worst thing about audiophile bs is that they can't explain the physics of their claims, instead they use made up words like "formed"... You don't know what you mean in real physical terms, so why would you dare claim it's a thing? Maybe, the difference you've been hearing from crossovers, have always just been degradation; in any case, you don't know, so don't say you do, unless you can explain exactly why, in a non-extremely-layman-vague fashion. Here's an EEVBlog forum excerpt regarding film cap degradation, but in mains capacitors susceptible to over voltage, something that shouldn't happen in an audio system: "It's actually a 'mechanism' rather than failure/degradation in most metalised film capacitors (apart from the really crap cheap ones, that is). The idea is to clear a fault that punctures the dielectric. Self-healing is normally indicated in the datasheet. Breakdown is normally the result of overvoltage or severe current transients. It's a desirable behavior in X-caps - you want them to self-heal on transients rather than fail short, as a foil capacitor would do. Unfortunately, the downside of self-healing behaviour is that it does result in progressive loss of capacitance as the metalisation burns away around new punctures, although it doesn't happen in low power circuits." So, they do change if you damage them, yes. That's not breakin, it's loss of capacitance, and if you consider it "broken in" at eg. 80% capacitance, you should have used capacitors matching that from the beginning, and have treated them within specs to not degrade them. As for the speakers, at least you're right. They have components exposed to mechanical stresses, in turn softening up, easily explainable, as opposed to the other thing.

Another topic with some combination of real audio fidelity impact and some snake oil involved. Spiders definitely can need to be softened through break-in. Surrounds…perhaps, depending on material. Electrolytic capacitors can need to be formed building the oxide layer inside but I consider any such component in the audio signal path a bad choice to begin with. Nothing in the electronic path should need break-in (or burn-in) for other than detection of initial faults such as bad solderings. Did I miss something?

People who say it's a myth imagine themselves enlightened men of science who don't believe in magic and voodoo like all these other idiots. But it's them that's being anti-science. Sound is generation by vibrations. Speakers are just vibration machines. The materials that vibrate to produce sound are stiff when new. It stands to reason that after they've loosened up, they can transmit sound more freely. In the world of musical instruments, it's not even much of a controversy. Solid wood acoustic guitars opening up, for one thing, is an unmistakle truism. And the principle is similar. New wood is stiff and needs to be vibrated. I better stop before I say vibrate one more time.