[Tyson]

At least, I hate having to go through break in while its happening.  I got a new Dayton RS28F silk dome tweeter and it sounded amazing for the first 2 days.  Now, after another 2 days of break in, it sounds shrill and spitty.  And yes, I measured it, and the measurements changed.  I adjusted my DEQX to compensate, but I think that once break in is complete, I'll have to take a new set of correction/setup measurements.  Ie, I'll have to start from scratch. 

But, the good news is that the RS28F is perfectly comfortable crossing at 1khz, and my system (which uses an SEAS Nextel 7" woofer on the mids and 3 Peerless HDS 7" woofers in parallel for bass) sounds MUCH better with a 1khz crossover point, especially since I do a fair amount of listening off axis.  Power response in-room is now VERY even, and sounds great from almost anywhere.

[jtwrace]

Post those break in measurements!

[sts9fan]

How do you know when breakin is done if you change the input?

[Tyson]

jtwrace,
I already deleted the old measurements.  But for the few minutes that I had both, I was able to do an overlay on a single graph, and there were some definite changes in the 1-2khz range.

sts9fan,
It's done when it starts sounding good again.

[Quiet Earth]

It's never done, it just slows down after a while. 

[Tyson]

Quiet Earth,
How right you are!  Specifically with moving mechanical parts like speaker drivers....

[Pez]

I've asked this once and I'll ask it again What in your system IS NOT a "Mechanical part"? the speaker cabinet? The cabling???? seems to me that every single element is mechanical in some respect whether we like it or not.

[Steve]

At least, I hate having to go through break in while its happening.  I got a new Dayton RS28F silk dome tweeter and it sounded amazing for the first 2 days.  Now, after another 2 days of break in, it sounds shrill and spitty.  And yes, I measured it, and the measurements changed.  I adjusted my DEQX to compensate, but I think that once break in is complete, I'll have to take a new set of correction/setup measurements.  Ie, I'll have to start from scratch. 

Yes breakin can be frustrating. 

Cheers.

[jtwrace]

jtwrace,
I already deleted the old measurements.  But for the few minutes that I had both, I was able to do an overlay on a single graph, and there were some definite changes in the 1-2khz range.

      Never delete data. 

[sts9fan]

I agree jtwrace. If you have no record then it never happened.

Tyson:  my question was/is how do you know it's not sounding better because you are fiddling with your crossover?  A rule o thumb when evaluating a change is to never change mrs then one variable at a time. If you adjust your crossover you have no way of correlating the change to breakin.

[BobM]

Don't you knoiw that it is YOU who are breaking in, not the equipment? 

So maybe you should put yourself on repeat, reverse phase on your left and right sides and keep playing for 100-200 hours before you make a judgement. 

Stay snarky.
Bob









PPS - this is a joke gentlemen

[Steve]

Don't you knoiw that it is YOU who are breaking in, not the equipment? 

Stay snarky.
Bob

I hope you are kidding.   

[Tyson]

I agree jtwrace. If you have no record then it never happened.

Tyson:  my question was/is how do you know it's not sounding better because you are fiddling with your crossover?  A rule o thumb when evaluating a change is to never change mrs then one variable at a time. If you adjust your crossover you have no way of correlating the change to breakin.

Crossover is exactly the same as before, no changes there.  When the tweeters were getting too spitty sounding, I just adjusted my EQ to tone it down a bit.  That's the nice thing about the DEQX, I can make these small adjustments during the break in process.  Without the DEQX I'd have no option but to suffer through it.

I managed to retrieve the data and pull some screen shots.  As you can see, it does indeed measure differently after a few days of use.

Before breakin (from my initial setup measurements when I dropped the tweeter in):






And how it measures now:





These measurements were taken without EQ applied, so they are "raw" driver response in the speaker boxes.

[Danny Richie]

I have done some extensive post and pre break in measurements, listening, etc.

I do not and have not ever seen any change in output level from break in and on a tweeter it is really not possible that any electrical or mechanical break in effects will have even a small effect on the output. Some woofers will show a very small mensurable difference in the bottom end, but that is about it in regard to output levels.

Secondly, it looks like you are taking in room responses (un-gated time windows). I am afraid that you will find that if you move the mic an inch or so in any direction that you will get some altered effects in the upper ranges due to cancellation and coupling effects of the room. Depending on the number of samples or if the sample was made as a random stop in time, then you might even see some pretty good changes in response from one measurement to the next without moving anything.

A funny thing is that the biggest error I see in people taking in room measurements of their system is that they often shoot a response of both speakers playing at the same time. 

Another thing to consider later on is that at some point if you can get the DEQX out of the signal path and use a really well designed passive network with a really good DAC then your system performance my come up to a level that you wouldn't have ever thought before.

Another thing I find odd is your description of what you heard. I am not saying that you didn't hear what you think you did. You are really listening and that is a good thing. But typically as drivers go through a process of burning in, the mechanical compliance changes soften up and the driver has a little less stored energy. It is like taking the shocks on your car and going from a firm setting to a soft one. So typically you hear less ringing and a softer overall sound.

[Nuance]

I have done some extensive post and pre break in measurements, listening, etc.

I do not and have not ever seen any change in output level from break in and on a tweeter it is really not possible that any electrical or mechanical break in effects will have even a small effect on the output. Some woofers will show a very small mensurable difference in the bottom end, but that is about it in regard to output levels.

Secondly, it looks like you are taking in room responses (un-gated time windows). I am afraid that you will find that if you move the mic an inch or so in any direction that you will get some altered effects in the upper ranges due to cancellation and coupling effects of the room. Depending on the number of samples or if the sample was made as a random stop in time, then you might even see some pretty good changes in response from one measurement to the next without moving anything.

A funny thing is that the biggest error I see in people taking in room measurements of their system is that they often shoot a response of both speakers playing at the same time. 

Another thing to consider later on is that at some point if you can get the DEQX out of the signal path and use a really well designed passive network with a really good DAC then your system performance my come up to a level that you wouldn't have ever thought before.

Another thing I find odd is your description of what you heard. I am not saying that you didn't hear what you think you did. You are really listening and that is a good thing. But typically as drivers go through a process of burning in, the mechanical compliance changes soften up and the driver has a little less stored energy. It is like taking the shocks on your car and going from a firm setting to a soft one. So typically you hear less ringing and a softer

Well said, Danny.  A big +1 from me. 

[Tyson]

Danny,
I took measurements of each speaker in turn, not at the same time  

For initial setup and driver correction I do nearfield measurements, and for room correction I do farfield measurements (which is what I posted).  I am pretty careful about measurement setup, but you are right, it was only one measurement point, and the mic could have shifted a bit.  I suppose a better option would be to take a cluster of several measurements from slightly different spots and average them together.  Which I can do with the DEQX, I just haven't. 

However, I did not bust out the mic just because I felt like measuring my speakers for the "fun of it".  I pulled it out because the top end started sounding a bit hot and spitty.  And that corresponds to the change in overall FR shape between the graphs.  So, I adjusted my EQ to compensate for the dip about 1khz a bit more and it started sounding tolerable again.

The "really" odd thing is that a few hours later, the system started sounding way too soft and subdued in the highs.  I didn't bother to remeasure (especially since my wife was now home), but removing the extra compensation from the 1khz range brought back a normal balance.  Weird, eh? 

Re: the DEQX and passive crossovers, I've heard a lot of very good passive speakers over the years and I prefer the sound of a good active implementation. 

[K Shep]

Tyson,

You're going to get one side saying measurements don't equate to what is audible.  Then the other side will say you didn't measure properly or you need to measure "your" room this way.  I read your post here as sharing what you experienced with your tweeters, then going back wards to prove your point.

I measure my room (using REW) when ever I make a change just to see how it reads, I also utilize a Velodyne SMS that has measuring functionality.

Point I'm trying to make is...your going to please some of the people some of the time.

[jtwrace]

I consider myself pretty good with kind of stuff...measurements and I've built my own speakers and passives.  BUT

I don't live it everyday and that means A LOT.  It's like any profession, unless you do it everyday it's pretty hard to master it.  I don't think that Danny is trying to just tell you that you're wrong but give you his advice and expertise (for free).  Of course you can disagree but when a professional has some advice, I listen and ask. 

[Tyson]

I don't think I'm actually disagreeing with Danny, re: measurements.  In fact, if you read my sentence starting with "Your are right...", then you can see that more clearly. 

Unless you are talking about passive vs. active speakers topic, in which case I do disagree.

[Tyson]

One tangential question I do have, which maybe Danny can answer, or anyone else for that matter, concerns the fact that measurements can (and do) vary based on small movements of the mic.  But, on the other hand, no matter where I sit, my speakers sound pretty much the same.  In other words, my speakers always sound fairly consistent, at no point do I think "Wow, they sound like Dynaudios from here", and this shift half a foot and think "Wow, and now they sound like B&W speakers from here".  The shifting in FR as measured by a mic would seem to indicate that there should be concurrent tonal shifts that are quite dramatic.  But, for the most part, my speakers sound pretty much the same regardless of sitting position, at least tonally speaking.