crossover "break in" time? (Off Topic)

by MikeH @, Monday, March 19, 2007, 09:36 (3964 days ago)

I can understand why drivers need to be broken in, the materials need to be worked/fatigued a bit to allow the cone to move easily.
I have been an electronics technician for over 15 years, "Breaking in" of crossovers and filters has me completely baffled.

"Burn in" as used in the electronics industry is mainly for detecting faulty components, if something is defective it usually completely fails very quickly. You work the device hard for 24 hours or so, if it doesn't go bang it will probably last for the warranty period so you box it up and sell it. I am interested in "Break in" not "Burn in"

Nothing will change in a well made inductor or resistor, I can only assume it is a chemical change inside the capacitors. If this is the case I expect they will sound good for a while then continue to "break in" until they stop working properly.

I've been searching on the internet and can only find Salesman style explanations. Logical technical explanations are hard to find.

I accept something sounds better after being used for a while, I want to understand exactly why.

Can someone point me in the right direction please?

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crossover "break in" time?

by Bert @, Monday, March 19, 2007, 09:59 (3964 days ago) @ MikeH

Hi Mike,

Nice topic...but I can't help you either.

I accept something sounds better after being used for a while, I want to
understand exactly why.

Can someone point me in the right direction please?

Never thought about it deeply and personally not really of interest because you can't do anything about that, in practise this is just the case. I can make it worse for you though, wiring needs to burn/break in too. A good test is to have an new interconnect burn/break in for some time connected in a certain direction. If you turn the wire around after a while (current flowing in the opposite direction) then the sound is very much changed and for the worse!

Nothing has changed to the frequency response but on a transparent sounding system the change can be described as having a new wire again that has to be burned/broken in again.

Its weird, I know and for technicians a brain torture simply because they want to understand why...

Ciao,

Bert

--
BD-Design - Only the Best!

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crossover "break in" time?

by MikeH @, Tuesday, March 20, 2007, 03:27 (3963 days ago) @ Bert
edited by unknown, Tuesday, March 20, 2007, 03:34

Never thought about it deeply and personally not really of interest
because you can't do anything about that, in practise this is just the
case. I can make it worse for you though, wiring needs to burn/break in
too. A good test is to have an new interconnect burn/break in for some
time connected in a certain direction. If you turn the wire around after a
while (current flowing in the opposite direction) then the sound is very
much changed and for the worse!

Current travels in both directions because it is an AC signal so I think it might be something else. Most people love to drive the Ferrari, some people like to take it apart to see how it is made. :grin:

What you are experiencing might be the surfaces of the connectors settling in or even oxidising slightly. If this is the case swapping left and right at both ends will have the same difference in sound as if you turned it around. This may be why people like to hard-wire instead of having connectors everywhere.

If I could understand some of this I could do something about that.
A most interesting puzzle!

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crossover "break in" time?

by Bert @, Tuesday, March 20, 2007, 09:11 (3963 days ago) @ MikeH

Hi Mike,

Current travels in both directions because it is an AC signal so I think
it might be something else.

Voltage then perhaps? I do not think that it has anything to do with the connectors, the same ones are still used when turning things around and the same effect isn't there when cleaning the contacts. I am sure that there is in some way direction of the current/voltage/potential/whatever... :yes:

Ciao,

Bert

--
BD-Design - Only the Best!

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crossover "break in" time?

by GC, Tuesday, March 20, 2007, 05:50 (3963 days ago) @ MikeH
edited by GC, Tuesday, March 20, 2007, 06:00

I can understand why drivers need to be broken in, the materials need to be
worked/fatigued a bit to allow the cone to move easily.
I have been an electronics technician for over 15 years, "Breaking in" of
crossovers and filters has me completely baffled.

"Burn in" as used in the electronics industry is mainly for detecting
faulty components, if something is defective it usually completely fails
very quickly. You work the device hard for 24 hours or so, if it doesn't
go bang it will probably last for the warranty period so you box it up and
sell it. I am interested in "Break in" not "Burn in"

Nothing will change in a well made inductor or resistor, I can only assume
it is a chemical change inside the capacitors. If this is the case I expect
they will sound good for a while then continue to "break in" until they
stop working properly.

I've been searching on the internet and can only find Salesman style
explanations. Logical technical explanations are hard to find.

I accept something sounds better after being used for a while, I want to
understand exactly why.

Can someone point me in the right direction please?

Mike

I have a couple of views, but they are far away from scientific, and concerns capacitors only.
(Eventhough we might compare a cable with a cap and a coil as well. (Small values though))

I have noticed that "aged" capacitors sounds "different" from new ones. That made me once many years ago think that some materials acts like red wine, cognacs and whisky etc. which gain quality over years, to a certain point at least. It undergoes some chemical changes.
Opposite results with fresh vegetables etc. though. :shame:

I tried, instead of letting my amps pump current into cross-overs over long periods, to give them some juice before soldered into the filters.
I took a vario AC trafo and connected the caps, turned up to certain value, close to their max. spec's, so that I almost could hear them cracking. Just a few seconds or so.

That made the same sound "difference" as aging, but done in a second.

Now another, maybe more understandable thing, is the trick to "bias" caps in a cross-over filter.
You take two caps connected in series instead of one. (Double the value of course). Insert a battery (9-40 VDC) in series with an 1MOhm resistor between the the center point between the caps and ground.
This bias loads the cap with a constant voltage and the sound is again "different".
The theory is of course that the the signal-electrons should not "drag" the tourgue hidden in the charge/discharge of the cap while playing music. (?).

JBL uses this "tweak" in their Everest and K projects.

In my terms of "different" I have not said anything about if all this sounds "better". You judge. :wink:

PS! I can not help thinking about good old passed away Mr. Kondo, who supplied the expensive Audio Note cables once upon a time. He had from his surplus of stock kilometers of cables collecting dust on the shelfes for years. These aged cables now sell for an outragious sum of money, claimed souding better than new ones.....Religion and beleives? :dntknw:


GC

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crossover "break in" time?

by Eddie @, Wednesday, March 21, 2007, 19:33 (3961 days ago) @ MikeH

Hello Mike,

I am not an electrical engineer, but I try for already a long time to find scientific reasons for audible differences. This is a niche market as you probably experienced.


Nothing will change in a well made inductor or resistor, I can only assume
it is a chemical change inside the capacitors. If this is the case I expect
they will sound good for a while then continue to "break in" until they
stop working properly.

My experience with resistors is indeed that they do not need braking in. What I once experienced is that resistors changed value slowly due to overheating. Capacitors and cables do change in time. About capacitors I can say that they are much more complicated than people realize. Besides capacitance they have resitance, inductance, leak current, dielectric losses and ..? The dielectric properties usually change considerably with temperature and life time. There is almost no research on the behavior of capacitors for high-end audio. The only paper that I once saw was a measurement of the frequency response of power supply capacitors. In this test Black Gates did not appear superior above other high quality types, such as Elna Cerafine. I once made the test in my amp which changing one Elna for one Black Gate and the last one sounded a LOT better.

With cables the explanation is even more difficult. More measurements are avalable on their resistance, inductance, capacitance and frequency characteristics, but these have very little correlation with the percieved sound quality. One small company in the Netherlands, Siltech, tries seriously to investigate cables for audio applications. They claim that the structure of the cristals of the conductors is an important factor for the transmission of very low voltages. They test their cables down to 1 nanovolt! This is required for low level details. Silver cables are better in this respect than copper ones. Silver with 1% gold is even better because the gold molecules fill the space between the silver cristallytes. The cristal structure of a wire is severely altered when a cable is taken out and put back and it seems to last a long time before it is settled again for optimum performance.

Another story that I heard a few times is that contact potentials can strongly influence the performance of a cable. For this reason some people prefer to have the output chain of the amplifier including the cables, connectors, voice coil etc. all from pure silver. The most expensive Audio Note equipment is made this way. However, good equipment can also be made with copper wire, Bert can demonstrate that for you.

The conclusion remain that very little investigations have been performed (because it is too expensive?). Practically all information comes from hear-say and trial and error and, of course, lots of nonsense is spread around on this matter. Well, that leaves something for us to find out.


Kind regards,
Eddie

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