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Cornwall IV and break in


Shakeydeal

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3 hours ago, Shakeydeal said:

Understood. Horns more than any speaker I have experienced are very sensitive to front end and amplification components. That's why I always tell newbies not to cheap out when it comes to what you pair with horn speakers. Mass market receivers, cheap digital amps, processors used as preamps, etc... have no place with a speaker that can potentially take your head off. Careful matching is in order.

 

I wouldn't say my Music Reference RM9 II/Don Sachs preamp are world class, but they are very capable. Especially the RM9. Just try to find one of these if you can. When you do, expect to pay a premium. My point is that I don't think my associated equipment is a bottleneck for CW IVs.

 

Shakey

Avoiding the quasi-religious topic of break in, where the minor MECHANICAL aspects of a woofer, not the voice coil, may or may not need break in, sounds to me like you would have a preference for TUBE electronics. Personally I LIKE bright speakers, which means FLAT without the B&K classic mild rolloff at 2 Khz. which is why I'm a fan of  DaveA MAHL super tweeters.  It compensates for my DULL HEARING!    LOL

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BTW, if you can do 10-20 hz, sine of square wave you will exercise the WOOFER cone better than music will, and much faster too. By pushing the excursion limits closer to the "Xlim" specification, your break can occur during a lunch break.

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47 minutes ago, ClaudeJ1 said:

BTW, if you can do 10-20 hz, sine of square wave you will exercise the WOOFER cone better than music will, and much faster too. By pushing the excursion limits closer to the "Xlim" specification, your break can occur during a lunch break.

Claude. How would I know where to stop with the output ?  Just a tad to far and things could get ugly, Not enough and I am not exercising the woofer to full benefit.  Is this done by ear listening for break up  or is there a measurement technique ?  Thanks   Joe

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35 minutes ago, joessportster said:

Claude. How would I know where to stop with the output ?  Just a tad to far and things could get ugly, Not enough and I am not exercising the woofer to full benefit.  Is this done by ear listening for break up  or is there a measurement technique ?  Thanks   Joe

All of my speakers are broken in, but if I had to do it, I would find a way to measure it free or cheap.

 

To quote Yogi Berra: "It's amazing what you can observe just by watching." ..............................doing it from 90 degrees with steel mm scale resting on the edge of the suspension would work, but never tried by me.

 

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23 hours ago, dtel said:

I remember MANY years ago I bought a new sports car, I asked my dad what should I do they say run it lightly for the first couple hundred hours and I had only had about 50 hours on it at that point ? He said no run it how you want, and change the oil at about 200 hundred hours, if there is a problem find out now, that was just what I wanted to hear as a teen. 

- all new car engines have specific break in additives added  into the oil  for the break in period  , and any new motor will have a mileage  period where you are told not to exceed certain RPM ranges and  gradually increase the RPM as mileage increases ,  the engine will release  a lot more particles , but when you flush the oil  - the break in oil  is gone and so are the special break in additives  that are made to  mix with the particles  -

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1 hour ago, joessportster said:

Is this done by ear listening for break up  or is there a measurement technique ? 

 

I have no idea how to measure it, (AC voltmeter?) but keep in mind sine waves are quite a bit more in gain/level than music signals.

So keep that in mind and start off low with respect to volume control when using a10-20Hz sine wave, and watch the cone movement being careful.

You'll know when you've gone too far when the driver cone starts rocking and making strange noises. Push it too far and it will go FRAP!!

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Lots of good points, including things I hadn't thought about before, like @joessportster comment about needing to start the breakin process all over if a speaker hasn't been used in a long time. But, I'm still skeptical about breaking in. Speakers are make from components, which are designed to specifications, then tested after manufacture to ensure they meet those specs. Since that is measurable, is there anyone doing before and after measurements on drivers after xx number of hours, to see if those numbers have changed? Is that something that PWK would have thought of and documented during his long career?

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34 minutes ago, Davecv41 said:

Lots of good points, including things I hadn't thought about before, like @joessportster comment about needing to start the breakin process all over if a speaker hasn't been used in a long time. But, I'm still skeptical about breaking in. Speakers are make from components, which are designed to specifications, then tested after manufacture to ensure they meet those specs. Since that is measurable, is there anyone doing before and after measurements on drivers after xx number of hours, to see if those numbers have changed? Is that something that PWK would have thought of and documented during his long career?

 

When you think about it, whether measurements would confirm the theory of break in or negate it, it really doesn't matter. Just like two amplifiers measuring the same doesn't mean they will sound the same. I'm not saying measurements aren't important, but everything that can be heard cannot be measured. I just sold a pair of speakers that exhibited changes all the way up to the 300 hour mark. I'm pretty sure my ears didn't become acclimated to the sound, they just gradually improved over time.

 

Shakey

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1 hour ago, Davecv41 said:

I hadn't thought about before, like @joessportster comment about needing to start the breakin process all over if a speaker hasn't been used in a long time.

I would think it's not the same, it's not like it's going to become new again, it may only take seconds if that much.

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29 minutes ago, Shakeydeal said:

but everything that can be heard cannot be measured. 

 

Shakey

Having worked in the semiconductor industry for a time, I learned that if you can smell it, you can measure it. Particles that go past your olfactory nerve and tell your brain that there's something there, also can go past a sensor and get measured and analyzed. A sound wave, which is energy, goes into your ear and tells your brain that there's something there, should also be able to be measured, and analyzed, and determination made that if it wasn't there initially, why is it there 300 hours later? Or if the measurements didn't change, but your ears think they did, then why? I understand that materials loosen up and take a set after a while, but I'm still not convinced yet.

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But surely you aren't saying that two amplifiers from different manufacturers with identical power ratings that measure the same will sound the same? 

 

How about two preamplifiers? Or two cd players? I'm not even going to bring up cables, that's a discussion for another day.

 

Shakey

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3 minutes ago, Shakeydeal said:

But surely you aren't saying that two amplifiers from different manufacturers with identical power ratings that measure the same will sound the same? 

 

How about two preamplifiers? Or two cd players? I'm not even going to bring up cables, that's a discussion for another day.

 

Shakey

I was just spouting my opinion on drivers. Amps, preamps, and CD players ( with digital to analog converters) are all analog electronics. Every component affects every other component in an analog circuit.

Cables? That's for another thread.

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On 8/6/2020 at 10:57 AM, Davecv41 said:

I was just spouting my opinion on drivers. Amps, preamps, and CD players ( with digital to analog converters) are all analog electronics. Every component affects every other component in an analog circuit.

Cables? That's for another thread.

You can have all digital signal from the recording chain all the way to the outputs of a digital cover these days can't you? It obviously has to end at the speaker which is analog.

 

As long as you have the cables going in the right direction, and at the exact length [something plus an eighth, or was it a quarter?] they won't matter.

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On 8/6/2020 at 10:25 AM, dtel said:

I would think it's not the same, it's not like it's going to become new again, it may only take seconds if that much.

You have to rotate the woofers 180 so that the top half of the woofer becomes the bottom and has the extra gravitational pull that the former top half has had in order to avoid breakin.

 

Chiefbone talked about breakin, and how he has manufacturers do it if they want their products to have the best chance for consideration. When they send him samples they come broken in to his specs so he can tell how they sound (and curve) in real world conditions. Then I guess he does a Max power rating on them and they catch fire. 

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On 7/24/2020 at 6:45 PM, Shakeydeal said:

Does anyone have experience with the CW IV and how many hours they need? Mine sound a little tight and bright with only a dozen or so hours on them?

Does the CW allow the user to attenuate the midrange and or tweeter?

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I'm not aware that it does, unless there is an adjustment on the crossover itself. But I can say that after more hours on the speakers and careful placement I am extremely happy with these speakers. There's not much I would change at all. Contemplating adding a sub (or two) in the future, but it's not an absolute necessity.

 

Shakey

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10 hours ago, dwilawyer said:

You have to rotate the woofers 180 so that the top half of the woofer becomes the bottom and has the extra gravitational pull that the former top half has had in order to avoid breakin.

 

I tried that but then the magnet was sticking out the front of the enclosure. :)

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