Driver burn in myths Busted

[mustang guy]

An interesting experiment was done by GR Research in which measurements were taken at different intervals of use for many different drivers.

Burn in Myths Busted

[moray james]

With all due respect I say BS and I won`t throw you out of my office as PWK might have done on a bad day.. Too many times I have started to make a comment about something burning in when my buddy would say almost exactly what I was going to about the sound.. Believe what you will and so will I. Best regards Moray James.

[Chris A]

An interesting experiment was done by GR Research in which measurements were taken at different intervals of use for many different drivers.

This agrees with the run-in drive tests done by Roy D. in Hope while I was once there. Note that most of the T/S parameter changes that I saw happened within
about half hour of the drivers being driven by a significant low
frequency voltage (a few volts peak-peak). I saw it with my own eyes on the test gear next to the anechoic chamber.

It's also easy to hear on compression drivers, for instance TAD TD-4002s took a few days of run-in at home using just music (cranked a bit [H]).

Thanks, this is a good article and needed to be documented.

[Utard]

The only way to prove/debunk this would be to do a blind test.

Get 5 people that believe in this.

5 people that think this is BS.

and 5 people that could go either way.

Have each person listen to a song on their home system for a few weeks so they know how it should sound.

Then have some speakers that have 80 hours on them. A pair with 10 hours.

And a pair of new ones for each person to listen to.

Then have them listen to the song in a random order on the speakers each person by themselves.

This is the only way to prove/debunk. Until then it is all heresy.

[Quiet_Hollow]

The only way to prove/debunk this would be to do a blind test.
Get 5 people that believe in this.
5 people that think this is BS.
and 5 people that could go either way.
Have each person listen to a song on their home system for a few weeks so they know how it should sound.
Then have some speakers that have 80 hours on them. A pair with 10 hours.
And a pair of new ones for each person to listen to.
Then have them listen to the song in a random order on the speakers each person by themselves.
This is the only way to prove/debunk. Until then it is all heresy.

This is utter nonsense. It's called metrology. The point of which is so that people can agree on things and eliminate "heresy". It's a requirement for design work and the only method through which anything can be directly engineered. Sure, everything is philisophical until you have to pay for it or be solely responsible for it. []

I saw it with my own eyes on the test gear next to the anechoic chamber.

..'bout sums it up. Right in line with the study from GR.

[moray james]

Knock yourself out and believe what you will. Developing a DBT for something like this is going to be like starting a cable thread. Lots of opinions and not much agreement as to what will work. I already know what years of listening tells me. Best regards Moray James.

[Guest " "]

A womans resistance in ohms when measured with one probe on the tip of her nose and the other probe on one of her toes is eactly the same if she is excited or if she is bored. I do not believe we have enough understanding of human perception to say that there is a measurement for everything we percieve.

[mike stehr]

A common knowledge of physics should dictate that a electro-mechanical thing such a speaker transducer will break-in/wear out over it's lifetime.

Of course one wouldn't hear the difference in a driver breaking in over time when the Fs only varies by a small amount. A few hertz lower Fs may or may not change things much as far audio perception over time. (although a couple drivers in the link did have a drastic change in Fs over the 80 hour time frame)

The same for a driver which is cold, the Fs is higher until the driver warms up. Things expand and contract...Surrounds and spiders wear out, cones dry up and change Fs...

[JJkizak]

IMHO Humidity and atmospheric pressure have the most effect on speaker performance.

JJK

[jacksonbart]

I think the color of the draps is more important

[Wrinkles]

I think the color of the draps is more important

No, I think it was thickness and length of the drapes, color is a mental game

Or maybe more importanly it was time of day

Or amount of food in your belly

Or number of beers consumed over time

Or...

[mustang guy]

I think the color of the draps is more important

Indeed. My drapes (at the cave) are camo on one side and forest green on the other. They are actually tarps I bought from Harbour Freight. []

[garyrc]

• Do horn loaded drivers that don't have to move as much as direct radiators change less with burn in?
• Is there anything to the idea that crosover networks, amplifiers, disk players, phono cartridges, and (getting crazy now?) even cables change with burn in?
• Has anyone studied whether the other variables other posters have mentioned (e.g., temperature of the room) are responsible for the same recordings on the same equipment, in the same room, from the same chair, at approximately the same SPL, sounding different at different times?
• Do you warm up your equipment before playing music? If you do, for how long?

[russ69]

It doesn't take all that long to put a million cycles on a pair of loudspeakers. My RF-25s broke in rather quickly, just a few hours (very noticeable). On the other hand the guys at Magnepan say that the speaker just has to go through some temperature cycles before they are broken in and playing time is not that important.

My personal opinion is that there is no set answer, each design and material selection would effect how the drivers change over time and some designs may be more stable than others.

[Chris A]

Do horn loaded drivers that don't have to move as much as direct radiators change less with burn in?

I think that if you are talking about T-S parameters which you can measure, my guess is that cone-type horn-loaded drivers also go through about the same amount of change. Look at the K-33 woofer in the Cornwall vs. in the Khorn.

Metal diaphragm compression drivers, even Beryllium diaphragms, undergo an audible change of their suspension stiffness. But note that the absolute amount of compression driver loosening to achieve the same relative effect as in a direct radiator is much less since the compression driver is connected to its environment through front-loaded horn.

Is there anything to the idea that crossover networks, amplifiers, disk players, phono cartridges, and (getting crazy now?) even cables change with burn in?

These are mainly electronic components,not analogue electro-mechanical components like drivers. I believe the answer to this question is "no", in terms of run-in.

Has anyone studied whether the other variables other posters have mentioned (e.g., temperature of the room) are responsible for the same recordings on the same equipment, in the same room, from the same chair, at approximately the same SPL, sounding different at different times?

Actually, if the poster above wasn't trying to be facetious, temperature is a big factor in the physical characteristics of air. The speed of sound is a function of temperature, not pressure. Humidity affects organic materials in the driver cones/domes, sometimes surprisingly so, and also controls a large amount of damping due to the effects of air in a room. The thermodynamic nonlinear properties of air in a horn are strongly affected by humidity in the high pressure areas of the driver and throat of the horn.

So the poster of those remarks isn't wrong, even if he perhaps wasn't trying to be serious, IMHO.

Do you warm up your equipment before playing music? If you do, for how long?

I warm my equipment up by playing music [8-)], but note that class A amplifiers, such as the First Watt JFET amp, require about an hour of operation to reach most of its steady state performance levels (temperatures), according to Nelson Pass. These effects are repeatable, i.e., this isn't "burn-in".

Tube electronics may take even longer, and actually continuously change at a slower rate due to tube burn-in and subsequent degradation over its relatively short lifetime as compared to solid state electronics and discrete devices, such as capacitors, which "burn in" immediately when turned on.

Chris

[Utard]

I think the color of the draps is more important

As long as the carpet matches the drapes it will all be ok.

[JBryan]

Garyrc:

"Do you warm up your equipment before playing music? If you do, for how long? "

In my experience, it takes about 30 min to an hour for tubed components to warm up. Digital amps require in the neighborhood of 2 hrs and SS equipment between 3 and 5 hours to properly stabilize and its best just to leave the SS and digital components on 24/7.

[Chris A]

This is from the First Watt F3 owners manual, written by Nelson Pass:

"The amplifier requires about 1 hour of operation to reach normal operating temperature, and this warm-up time is appropriate for the most critical listening, but is not otherwise an issue. The amplifier’s final adjustments were..made after an hour, but the performance difference between 1 minute and 60 minutes is not very great.

I do not personally see a reason to run the amplifier all the time, but you can do that if you want to. The power supply capacitors are likely to last about 15 years or so, and while they will slowly dry out just sitting there, they will have a shorter life span with the amplifier running constantly. Also, at 200 watts it makes economic sense to shut the amplifier off if you aren’t planning on using it for the rest of the day"

Chris

[JBryan]

I am familiar with Nelson Pass and have heard several of his designs and would love to try one in my system someday. Most of his First Watt products (including the J2 & F3) are designed to run in Class A mode and thus should be warmed up similar to tube components. His suggestion to allow an hour warm up for stabilization is good advise from someone who definitely knows his stuff - take it to the bank.

[JBryan]

I certainly understand the drawbacks of leaving gear on 24/7 - both in 'Green' matters and expense. The only pieces of gear I leave on at full power is a pair of digital amps, although I do have a couple of tubed pieces that I keep on stand-by. I would actually prefer to turn the digital amps off but the few times I have, the bass bins that i drive them with sound a bit dull, slow and muffled for a couple of hours. Fortunately, at idle, the digital amps use about the same energy a s a flashlight bulbAside from the few tmes I have changed out gear, the amps have been on for the last 9 years with no problems (knock on wood). The efficiency of an amp or preamp is fairly easy to determine - after running for a few hours, touch it near the power transformer. If its warm, its not very efficient and hotter means even less efficiency.