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"Breaking In" AKG 701s?

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pwhodges

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Re: "Breaking In" AKG 701s?

PostSat Jun 12, 2010 6:29 pm

David Pinnegar wrote:the instructions are to "run them in" for 30 hours or so
If I was paying loasamoney for exotic speakers, I would expect a mere 30 hours of "running in" to have been done for me before delivery - but I suppose that this way you get to buy in to the supposed benefits.

A chemical bond either is or isn't, so:
David Pinnegar wrote:the vibrations loosen chemical bonds
is meaningless. Would you like to try for a more convincing explanation?

Paul
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kwbmusic

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Re: "Breaking In" AKG 701s?

PostSat Jun 12, 2010 7:40 pm

Could be that it is the listener's ears that are being broken in. We all tend to subconciously adjust our hearing to that which we expect to hear. Telephones, for instance, carry only a narrow band of sound width, but when listening to a known voice, the character nuances are added by our mind.
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jkinkennon

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Re: "Breaking In" AKG 701s?

PostSat Jun 12, 2010 8:43 pm

Steinway pianos are broken in at the factory. For a real no-nonsense reason relating to compacting felt in the hammers. And presumably to lessen the need for regulation after the first week of use.

Some thinks get broken in. Steinways, Ford pickups (or at least that used to be the case), but NOT speakers and headphones. Get a grip folks! Stop believing everything you read.

If "chemical bonds" are changing then tell the manufacturer to buy a decent brand of epoxy.
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pat17

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Re: "Breaking In" AKG 701s?

PostSun Jun 13, 2010 8:19 am

I did have to break in my earphones by the way, but this is linked to the somewhat electrostatic technology they are using. Same for the - ESL - loudspeakers. With more classic models, I do not think it is really necessary to go through it. :wink:
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ajt

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Re: "Breaking In" AKG 701s?

PostSun Jun 13, 2010 9:19 am

If speakers and headphones need breaking in to sound their best, how do companies ever sell them? Surely anyone investing in some good quality gear is going to want to hear it first?
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Eric Sagmuller

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Re: "Breaking In" AKG 701s?

PostSun Jun 13, 2010 9:58 am

From much reading I've done, I believe there is some credibility to breaking in the woofers in an acoustic suspension speaker that uses a woofer that has a fair amount of x-max or displacement. The surround tends to become a bit more flexible after playing awhile. At least some manufacturers break in there drivers and then measure the parameters and use that data to tune the box. In most cases I think that the break in would only really affect the low end output by improving the bass that is produced. As a whole though for where most of the critical music is at the mid and upper frequencies, it don't think it means diddly.

ESL speakers use a large diaphragm of Mylar or such, at least the ones I built used this, and can't see this becoming more flexible over time.

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pat17

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Re: "Breaking In" AKG 701s?

PostMon Jun 14, 2010 3:27 am

ajt wrote:If speakers and headphones need breaking in to sound their best, how do companies ever sell them? Surely anyone investing in some good quality gear is going to want to hear it first?


Breaking in is improving the sound quality, without changing it dramatically. In other words, even without going through that stage, the sound is quite good.

Besides, for the equipments I am using, it was mentionned a period of 100 to 300 hours was necessary to achieve an optimum audio quality. I do not think any manufacturer may afford to keep its equipment for such a long time till it is finished before it can sell it.
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pat17

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Re: "Breaking In" AKG 701s?

PostMon Jun 14, 2010 3:29 am

Eric Sagmuller wrote:ESL speakers use a large diaphragm of Mylar or such, at least the ones I built used this, and can't see this becoming more flexible over time.


I am not on the technical side at all, and I do not know what material is used for my ESL,but it's a given fact there was some change with time - for the best I mean. Is it auto-suggestion from my side? Quite possible, but I do not think so - I may be influenced in quite a number of directions, but not when it comes to audio and video / pictures. :wink:
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ten87

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Re: "Breaking In" AKG 701s?

PostMon Jun 14, 2010 5:39 am

jkinkennon wrote:Why should we think that 300 hours of break-in would result in improved sound rather than degradation? Seriously, if breaking in a speaker or set of headphones results in significantly different sound then there is a manufacturing defect that would need to be addressed.

This is right up there with "monstous cables" and my favorite, the old Wurlitzer speaker which amounted to a horn driver coupled to a trombone bell -- yeah, really!


I think 300 hours is WAY overkill, but according to some of the things I have read, there is a break in period. Here are two pages to read:

http://www.gr-research.com/burnin.htm

http://www.gr-research.com/myths.htm

When you buy a new car, there is a break in period to allow the piston rings to seat. The fuel mileage of my Toyota increased steadily for the first 5000 or so miles, and then slowed, but still increased until I hit about 10000 miles. They told me this would happen, and I didn't believe them. But it did!

When I built my speakers, I did burn in the drivers, as recommended, with a 40hz test tone for 10 hours prior to installing them in the cabinets. According to some comments on the BFM Loudspeaker Design Forum by those who do this for a living, you reach a point of diminishing returns. Things will loosen up in the first few hours, with the amount of improvement dropping off substantially after that.

Being that headphones are just tiny speakers, there probably is a break in period. But I doubt any of us could hear much of a difference. How much excursion does a driver in a set of headphones really have?? If they sound good to you, just use them and enjoy!

Terry
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Re: "Breaking In" AKG 701s?

PostMon Jun 14, 2010 2:03 pm

It is one thing to discover some subtle changes in speaker compliance and quite another to explain statements like "the sound opened up". While the changes GR-Research found may in fact be repeatable, they certainly do not have the kind of equipment or test controls to be expressing results in 6 significant digits. I've done some test equipment calibration and have an idea of what can be measured and how accurately.

I'd agree that the suspension of a well-worn speaker may be measurably different than that of a fresh example. The catch is how you know whether the sound got better. Even if the frequency response improved in one enclosure, the same speaker working against a slightly different mass of air might well look worse. I guess it sounds sort of psuedo-intuitive to say that the suspension softened and the sound "opened up".

If this sort of logic were to prevail we would have to run our speakers at exactly the right volume level so as to heat the voice coils evenly and achieve perfection. No more quiet nights with the stereo as it just wouldn't sound right.
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David Pinnegar

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Re: "Breaking In" AKG 701s?

PostMon Jun 14, 2010 5:30 pm

Hi!

In relation to the clumsiness of my explanation of "chemical bonds breaking up", what I mean is that the structure of the foam which will be amorphous "learns" to move more freely in one direction than another, long chain molecules which are ravelled up will be stretched and this requires weak bonds between adjacent strands or plastic "fibers" to be broken. If one puts a 500Hz signal onto such a speaker for 30 hours thats 30x3600x500 stretches - thats 54000000 movements. Yes perhaps one should expect to see this make a difference to a plastic (I mean this as a term describing flexibility) substance.

Best wishes

David P
http://www.organmatters.co.uk
David Pinnegar, B.Sc., A.R.C.S.
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Grant_Youngman

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Re: "Breaking In" AKG 701s?

PostMon Jun 14, 2010 9:09 pm

Hmmm ..

Even though I partly started this (surprisingly polite discussion) out by called the notion of "breaking in" a pair of AGK-701's in a drawer for 300 hours to use with HW "ridiculous" (and I stand firmly by that comment), I do not necessarily classify "breaking in" of mechanical/acoustic devices in the 100% snake oil side of audiophile science (and/or wishful thinking, whichever). I do, after all, have to "break in" my joints virtually every morning, and I certainly feel more "open", "transparent", "effortless", and "liquid" after doing so :mrgreen:

Nonetheless ...
Grant
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Re: "Breaking In" AKG 701s?

PostMon Jun 14, 2010 11:11 pm

Excellent Grant! Ain't we all like a dog with a bone on this topic! At least I'll include myself, don't want to offend anyone else...
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pwhodges

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Re: "Breaking In" AKG 701s?

PostTue Jun 15, 2010 5:52 am

I feel much the same as Grant. My problem is not with the possibility that materials can change their properties as a result of movement so much as with the language used to describe the (possibly) audible effects. Audible changes should also be measurable (yes, I know how hard correlating some measurements with their audible effects is, so no need to go down that road here).

Paul
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David Pinnegar

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Re: "Breaking In" AKG 701s?

PostTue Jun 15, 2010 11:00 am

Hi!

My experience with the foam mounted loudspeakers, in common with others, is that they begin to sound less brittle, more relaxed. It's really a case of material fatigue - how many of us have bent a piece of wire one way and then the other to break it, or folded paper backwards and forwards to make it tear more easily?

The other day I had a unit in for repair (I don't recommend the units for complex organs as they can go awry when you're not looking), and it was apparent from the mere feel of the stiffness of the cone mounting that it had not been run in. Of course that is going to have an audible effect.

With headphones, then the diaphram and the ear drum are fairly close coupled so one will hear a difference. If one is using an exotic driver in a horn then _all_ movement is amplified, often 0.1 watt being all that's needed to drive it for an acceptable listening volume, so the very very small differences in the mechanical properties of the foam mountings, normally irrelevant, are now amplified and become audible.

Best wishes

David P
http://www.organmatters.co.uk
David Pinnegar, B.Sc., A.R.C.S.
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