
Speaker conditioning or as some people like to say "break in" the driver, what on earth?
Nonsense...said the folks on the left movement and truth said the far right movement lol - ok seriously lets take a dive down this rabbit hole and try understand what this is all about.
First it is important to understand we have a range of parts that make up our speaker but for now we are going to look at what is often referred to as our soft parts, our soft parts are the damper also sometimes referred to as a spider and of course our cone is also a soft part but for the sake of keeping things simple we will focus on the surround. These parts serve to hold the speakers voice coil and cone in position but also act as a a spring which takes a little effort to stretch out and compress in both directions, they have a capacity to them.
This means they can only stretch out so far and in return they can only pull back a given amount, car audio speakers are often highly over mechanically damped which means these parts are extremely stiff, some Hifi speakers and even pa speakers can be pushed back with little to no force and will return to a point of rest just like a shock on a car.
We have a range of different types of materials that can be used for our damper and surround with each of them having a different dynamic to them, lets dive into our damper material for just a second and look at some of the most common materials used.
- Cotton
- Nomex
- Cotton & polyester blend
- Acrylic
- Coated - which can be a silicone or rubber
- Aramic fibers and other exotic materials
Each of these materials have some good points about them which include:
- Stiffness
- Compliance Cms think of it as the elasticity
- Strength - how much force it can withstand before it rips
- Bla bla bla and the list goes on
The same bag of tricks apply to our surround which is often a foam, rubber or a cloth material in various mixtures. These different types of materials also share the same or similar properties as our damper, these materials are often formed under lots of heat and pressure.
Just like leather shoes the material will start to soften and stretch over time, meaning the speaker you just purchased will become a different speaker 5 years down the line as the driver will experience some wear and tear not to forget due to heat.
However we will reach a mid point when the speaker settles and ultimately is the speaker will reach a general equilibrium once in use, premium brands spend lots of money on R&D to ensure a long shelf life and part of the reason why they are so expensive.
So the question is - does it matter?
Yes especially if you are designing the speaker enclosure yourself, often people who get into Diy that can test a speaker on something like Dats freak out because what the data sheet said they will get is not what they are seeing.
Qms, Cms, Vas, Fs Qts are all wrong but forget that that speaker is like a brand new car which has a great smell new ;) Driving the car or our speaker changes things up after time!
Here is a practical example using the Nexus 18-1000 which has a dual silicone spider, when it's made the speaker is beyond stiff vs the driver after many hours of playing compared in the "pro 218 enclosure we have in our store.
Red is the stiff driver & Blue is our softened or "broke in" driver - look at the difference, remember its all the same speaker!
Winisd simulation
Rather contrasting, we can see we have a large difference in our Q, our softened speaker has a large hump in the response which might be desirable depending on what you are doing!
we can see the effect of this shift on all of our graphs, which ultimately effects the end result. for the car audio guys this is why sometimes speakers "bang harder" with age its just by luck things swing in your direction and the reverse can be applied it started off banging but 6 months down the line its not as potent.
Theoretical shift of impedance
A note to keep in mind both these curves will be effected by driver level, these shift are actually helpful to test once we have designed and built our enclosure by sweeping to obtain the Zma file. We can assume that if our peaks are close between simulation and measurement that we have done a good design but in reverse the shock and horror on my face if I had this difference between measured and simulated & it looked like this. Again this is a shame with many imported speaker brands, if information is provided at all most of the information is never correct in the first place so that box design is a thumb suck guess and you never will take full advantage of the speakers performance.. ever.
Lets round it up and not get to technical and conclude that breaking in a driver does in fact affect the performance characteristics of a speaker, is it worth it - yes.
Lastly something to keep in mind, when you own a really good driver and you abuse it through events its recommended that you replace and recone the driver to bring it back to it's formal glory after a couple of years for all you touring folks under constant use at high levels.
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