Danny Richie Audio Myths on “Electrical Burn In”

[Sgt. Ear Ache]

Changes over time are what IMAX claim:

US Patent #9648437: Systems and methods for monitoring cinema loudspeakers and compensating for quality problems (Assignee: IMAX Corporation.)

A few quotes (my emphasis):

"[Claim] 5. The method of claim 1, wherein the test signal comprises at least one of: an impulse signal; a chirp signal; a maximum length sequence signal; or a swept sine signal."

"[Claim] 7. The method of claim 1, further comprising: tuning a theatre sound system prior to determining the difference, the theatre sound system including the loudspeaker."

"[Claim] 10. A system comprising: […] an equalizer unit adapted to (i) store the signature response of the loudspeaker, (ii) correlate the signature response to the optimal response, the signature response indicating what the optimal response should be at the suboptimal location of the microphone for the loudspeaker (iii) determine a difference between the signature response and the subsequent response, the difference representing changes in the loudspeaker since capturing the signature response,(iv) compensate for changes to the loudspeaker by modifying an audio signal based on the difference to generate a compensated audio signal and providing the compensated audio signal for output by the loudspeaker such that a response to the compensated audio signal represents the desired response by the loudspeaker in the patron-seating area of the theatre."

As for testing whether the system is functioning, IMAX Digital systems (worldwide) are remotely monitored from IMAX's Network Operations Center in Mississauga, Ontario. In case of driver failure, where possible (e.g. a blown subwoofer driver) the system can be set to compensate for this (e.g. by increasing the output of the remaining subwoofer drivers,) and in all cases a field technician can be dispatched for the installation of replacement parts. Incidentally, the projection system is remotely monitored and automatically recalibrated every day, too.

Yes, none of which necessarily implies the changes in the loudspeaker are a result of burn-in such as it's referred to by audiophiles...

"Cinema loudspeaker systems need to perform reliably for extended periods. This is in conflict with the natural changes in the loudspeaker characteristics due to aging or changing environmental conditions, such as temperature and humidity. These natural changes, among other changing performance characteristics, are a typical problem that occurs over time. Other potential performance issues include (i) one driver in a cluster of drivers within a loudspeaker fails or is experiencing a degradation because of a loose connection or otherwise; (ii) a fuse blows, leaving inoperable the mid-range driver(s) or high range driver(s); and (iii) audio amplifier degradation or failures to degraded sound in the theatre. One approach to recognize one or more of these deficiencies is to repeat a theatre sound system tuning test to determine a performance deficiency.
Additionally, the acoustics of the theatre hall can change depending on the number of viewing patrons present (i.e. acoustics can be different if the theatre is full than if the theatre is nearly empty) and the location within the hall of where the patrons are seated. If the acoustics of the hall has changed, causing a reduction in sound quality, adjustments to the equalization of the sound system may be required to compensate for the change."

 

[xr100]

Yes, none of which necessarily implies the changes in the loudspeaker are a result of burn-in such as it's referred to by audiophiles...

Indeed it has nothing to say about the rate nor quantum of changes to frequency response. A characterisation of typical changes to driver behaviour over time, with differing usage patterns and for different driver types would, however, be interesting.

In this context, it is at least worth mentioning that the sound systems in an IMAX auditorium are called upon to generate very high output levels for many hours a day in order to hit reference SPL's in the seating area. IIRC, HF compression drivers in such demanding applications can over time suffer from a loss of upper frequency output.

Come to think of it, the effect of "kids" (or clumsy adults!) poking in tweeter domes or dust caps, other visually obvious changes, or mechanical damage, would be useful, too.

 

[Hayabusa]

What would it be if you measured it twice in a row?

I did several measurements, its repeatable, only in the 10Hz region some change due to low signal levels.
Next time I measure I will keep the repeated measurements to show you.
Would you expect short term changes with these speakers?
What I could imagine is a small change directly after power on as the HV maybe needs to settle?

 

[Hayabusa]

What would it be if you measured it twice in a row?

3 repeated measurements:

And the full compare day1, +3w, +4d
So also after 4 days there is a very small difference..
(lets repeat this in a few weeks again!)

 

[maltux]

I read a thread in the Harbeth User Group forum between Danny Ritchie and Alan Shaw of Harbeth speakers. Danny did not fair so well. Ten years ago I bought one of GR Research's speaker kits and still have them today. I use them to listen to in my Den attached to my computer. I prefer the Overnight Sensations to these. I do not like to disparage another mans living but I would personally not buy anything from Danny. Sadly most YouTube audiophile reviews are garbage, just rehashing marketing blobs of goop.

I consider myself an equipment-phile as admittedly I am awed by shiny cases and pretty lights.

 

[Rincewind]

I used to work for a notable manufacturer of active loudspeakers. During the very early stages of production we used to burn-in (24 hours of very loud pink noise) a batch of assembled product to test that the production processes were robust for the new product. As a by-product of this we had before and after measurements of all the loudspeakers in this batch of 50 loudspeakers. I compared them statistically and found that the ONLY change was in the approximately 500 Hz region and that change was a 50 Hz shift downwards in frequency of a small 0.5 dB bump. The cause of this was some of the fibres in the spider weave breaking permanently. Once they had broken no further change would be expected long-term. Clearly this change is small enough to be inaudible. And before you ask I am not at liberty to share this graph because I not longer have access to a copy (see first six words of this posting). Burning-in loudspeakers is a waste time and energy. Stop doing and stop talking about it! Get on with listening to the loudspeakers ;-).

 

[TomB19]

What do actual flat earthers use as a pejorative for people they disagree with?

Globists

 

[GXAlan]

Woofer break in can happen, but that is different than “electrical burn in”

http://www.audioheritage.org/vbulle...061-ME120H&s=abd92cbcee387c922ce82402fd4d3ab0

JBL internal documents mention this difference in the free air resonance of a driver new vs broken in

 

[amirm]

Woofer break in can happen, but that is different than “electrical burn in”

http://www.audioheritage.org/vbulle...061-ME120H&s=abd92cbcee387c922ce82402fd4d3ab0

JBL internal documents mention this difference in the free air resonance of a driver new vs broken in

We have addressed this before. Once you put these drivers in a box, the difference becomes negligible.

 

[Hayabusa]

We have addressed this before. Once you put these drivers in a box, the difference becomes negligible.

Have you done measurements to confirm that reasoning?

 

[amirm]

Have you done measurements to confirm that reasoning?

I saw them in private presentation at harman. Dr. Toole provides a summary in his book but not the measurements.

 

[Hayabusa]

I used to work for a notable manufacturer of active loudspeakers. During the very early stages of production we used to burn-in (24 hours of very loud pink noise) a batch of assembled product to test that the production processes were robust for the new product. As a by-product of this we had before and after measurements of all the loudspeakers in this batch of 50 loudspeakers. I compared them statistically and found that the ONLY change was in the approximately 500 Hz region and that change was a 50 Hz shift downwards in frequency of a small 0.5 dB bump. The cause of this was some of the fibres in the spider weave breaking permanently. Once they had broken no further change would be expected long-term. Clearly this change is small enough to be inaudible. And before you ask I am not at liberty to share this graph because I not longer have access to a copy (see first six words of this posting). Burning-in loudspeakers is a waste time and energy. Stop doing and stop talking about it! Get on with listening to the loudspeakers ;-).

I agree that 0.5dB bump is unlikely to be audible.
So I assume the drivers (esp. the woofers) in the test where not already having some burnin time at their manufacturer?

That you could not find a difference in your specific situation does not mean all cases are a waste of time. See my post above #64 where I show a significant change within weeks in this case for an electrostatic speaker.

 

[maty]

I have only detected the difference, and much, with the small 5.25" coaxial of my KEF Q100. Until then I had never perceived differences. I always judged the sound after a while of operation after connecting them the first time, and nothing or was so minimal that I could not pass a test.

Instead with those I considered returning them. I decided to wait a few hours and the sound improved but not quite. After many hours appearing the bass ones that were missing at the beginning, whose absence made them unbearable to me.

I thought they were defective, so bad they sounded compared to what I had at the time (Boston Acoustics A25, new, that I won in a eBay bid at a really low price, for a familiar, to the TV).

 

[digicidal]

I think all audiophiles should commit to a minimum 1000 hours process... much like breaking in a new car... for the first 500 hours you must only listen at very low volumes... then slowly increase the level until you've reached the 1000 hours required. Each 200 hours the genre should be switched up starting with only quiet string ensembles and ending with rap or club music at maximum volume (pipe organ as an optional alternative last step).

It wouldn't end the discussion... but it would delay it by at least a couple months - and it would expose many to new genres of music which might just give them something truly subjective to argue about.

 

[Rincewind]

The drivers were straight off the supplier's driver line. They would only have had basic production testing and this is a lot quicker than you might imagine - certainly not burnt-in in the way we are talking about here.

I would suggest that a product that changes its performance enough that the changes are audible after burn-in cannot be trusted. I would return any loudspeaker than changed audibly after 24 hours of use and I suggest you do the same because how much more will it change over its lifetime?

 

[Darkweb]

I used to work for a notable manufacturer of active loudspeakers. During the very early stages of production we used to burn-in (24 hours of very loud pink noise) a batch of assembled product to test that the production processes were robust for the new product. As a by-product of this we had before and after measurements of all the loudspeakers in this batch of 50 loudspeakers. I compared them statistically and found that the ONLY change was in the approximately 500 Hz region and that change was a 50 Hz shift downwards in frequency of a small 0.5 dB bump. The cause of this was some of the fibres in the spider weave breaking permanently. Once they had broken no further change would be expected long-term. Clearly this change is small enough to be inaudible. And before you ask I am not at liberty to share this graph because I not longer have access to a copy (see first six words of this posting). Burning-in loudspeakers is a waste time and energy. Stop doing and stop talking about it! Get on with listening to the loudspeakers ;-).

So you provide a concrete example of a driver response changing after break-in, and then go on to conclude that since your sole anecdotal example could be inaudible (did you test?) to human ears you go on to conclude burn in is completely a “waste of time and energy”?

Seems like very shaky ground to stand on and shoddy logic.

 

[GXAlan]

I saw them in private presentation at harman. Dr. Toole provides a summary in his book but not the measurements.

That makes sense coming from a Harman presentation — they know everything and measure everything. But to Rincewind’s comment, Harman knows where the final performance is going to be so they have designed their speakers with that knowledge.

I also think that as woofer design has improved and materials have improved, the need for break in has changed. We no longer use rotting foam for surrounds. It is likely that older magnet structures and surrounds are different.

Likewise, consider REL subwoofers. They recommend breaking in their subs, AND THEN re-torquing the screws that mount the driver to enclosure after the break in period. That implies that the screws are at a certain tightness at shipping, not threadlocked, and then after break in, you may expect a few more turns.

The audibility of this is a separate question.

The other thing, is that with loudspeakers at least, I find that in the first 100 hours, I end up playing with toe-in and position. It is perhaps a few minutes every few days or so. At the end of 100 hours, the speakers may sound better than when they were first brought home, but it is not an apples to apples comparison. It’s really a tuning of the specific speaker for your room that happens subtly over 100 hours.

 

[Rincewind]

Dear Darweb, See my second follow up post just above yours. This narrows the scope of my (admittedly) sweeping generalisation.

 

[Sgt. Ear Ache]

So you provide a concrete example of a driver response changing after break-in, and then go on to conclude that since your sole anecdotal example could be inaudible (did you test?) to human ears you go on to conclude burn in is completely a “waste of time and energy”?

Seems like very shaky ground to stand on and shoddy logic.

the sort of "burn-in" he's referring to would have occurred after about 30 seconds of use and is the sort of thing that those of us who believe burn-in is hogwash commonly allow as being a "slight possibility." And what's so shoddy about saying something that is very likely not audible is very likely not audible? There's not all that much mystery about audibility levels...and it's far far far less "shoddy" than someone claiming they can hear a dramatic improvement in sound quality listening to a speaker after 100 hours of burn in compared to what they heard prior to burn in.

 

[Verdinut]

So if Speakermanufactorer talk this.

https://www.eminence.com/speaker-break-in/

Then it's absolutly no wonder that people like me think there is something or?

The Eminence article must have been written by their marketing department because not everything they say about break-in is true.

First, let me say that from my own experience as a speaker builder, most cone loudspeakers but not all will undergo a loosening of their suspension after several hours of play, but any changes in their performance are minor and inaudible for all practical purposes.

What happens with the Thiele/Small parameters is that the Fs will decrease by a percentage up to about 15%, but the Qts will increase, so that the ratio Fs/Qts remains constant before and after break-in. Consequently, It's useless to try to adjust a ported box tuning after the break-in period.

What Eminence say about the sonic results such as an increase in overall warmth, slightly deeper/fatter lows, and warmer/smoother highs is just pure marketing bullshit.

In a previous post, I saw a chart indicating that with break-in on several drivers, the Qts was decreased along with the lowering of the FS. I just don't believe that. In his book "Loudspeaker Design Cookbook", Van Dickason explains what break-in in loudspeakers is about.

Let me annex the impedance and phase angle response curves of a MTM speaker which I built 5 years ago. Try to find a phase angle response as good as that. I've never seen a commercial speaker come close to that linearity: