Break In - What, Why and How

Posted by SoundQubed on 9/1/2016 to Tech Articles
Break In - What, Why and How




BEFORE BREAK IN
AFTER ~16 hours of play
 Piston Diameter = 209.6 mm
Piston Diameter = 209.6 mm
f(s)= 48.45 Hz f(s)= 42.39 Hz
R(e)= 1.77 Ohms R(e)= 1.78 Ohms
Z(max)= 18.86 Ohms
Z(max)= 13.89 Ohms
Q(ms)= 7.833
Q(ms)= 5.38
Q(es)= 0.813
Q(es)= 0.792
Q(ts)= 0.737
Q(ts)= 0.690
V(as)= 9.281 liters     (0.328 cubic feet)
V(as)= 15.800 liters     (0.558 cubic feet)
L(e)= 0.72 mH
L(e)= 0.72 mH
n(0)= 0.12 %
n(0)= 0.14 %
SPL= 83.03 1W/1m
SPL= 83.71 1W/1m



Woofer break in fact or fiction.

The age old question. "Do I really need to break in my subwoofer?". Well, that depends.  Some woofers such as PA and studio may not require this due to having  high compliance suspension. These speakers do not see an appreciative difference in performance pre and post break in.  On the other hand there are subwoofers such as ours that have what we call 'low compliance' (elastic deformation)  that  require a break in period that will loosen the suspension over the  course playing. Long term this will maintain peak performance long beyond the life cycle of a woofer made with looser suspension.Think of it as a fresh built motor. Once you get through your first oil change you'll see a rise in your gas mileage and you'll be able to romp on it a little harder,  it's the same concept with our woofers and many others on the market. 

 

Why do we suggest breaking SoundQubed subwoofers?

Giving your new woofer a few hours of break in will let the spiders loosen up and allow for higher excursion and the ability to play lower frequencies.  Along with your T/S parameters changing once the woofer is fully broken in, you are less likely to damage the coil as it will move more freely in the gap  which allows for better cooling and less build up of heat.

 

How can you properly break in a subwoofer?

There are a few different options when it comes to breaking in a subwoofer.  It’s highly-recommended to have a steady load on your subwoofer during the break-in period. Option I and Option II both help loosen up the suspension however the woofers will keep loosening up over the duration of their lifetime! Keep in mind that music tracks with sporadic or intermittent bass won’t do the trick

Option I:  The most common and easiest method; Install your woofer as you normally would. Play  your favorite music at low to medium volume and 1/2 gain for 2-3 weeks  After a couple of days you will begin to hear the woofer start to break in and get cozy in its new home. As the Fs drops and the suspension loosens up you'll notice that you will get lower and louder with less power. After 2-3 weeks you can set your gains accordingly and listen at normal levels.

Option II: This option is a little more in depth and requires  some nifty tools but yields a much faster break in. We do this by free airing the woofer (playing the woofer without an enclosure).

Tools Needed:
• Tone Generator, your phone will work for this; download a tone generator app from your app store.
• 3.5mm jack to RCA so you can plug your phone directly into your amplifier.
• A solid mounting surface for your woofer. Do NOT free air your woofer with the back-plate against a surface as the woofer can't breath.  - We suggest mounting your woofer in a piece of wood with enough area on either side so you can suspend it between to chairs or tables. Make sure you weigh the sides down so it can't walk off.
• An Amplifier.
• A Clean signal. You can mount your SoundQubed amplifier and use the remote knob to see this signal.
• 8-16hrs of free time.

Now that you have gathered your tools you can begin the break in process. Play a sine sweep of 30hz-60hz if your app can not do this play a 40hz tone for the duration of the break in. We suggest 8-16 hours  for a solid break in time. You can set it with a good clean signal overnight. Once this is done you are ready to install and be on your way.

NOTE: During Option II Please check frequently to make sure your woofer is staying cool aka stir frequently.


 What can happen if you do not properly break in your subwoofer?

If you don't allow for a break in period you could run into one of the issues below.

• Burned or unwound coil: Burned or unwound coils can be caused by the buildup of excess heat and a distorted signal.  Stiff spiders leave you with less suspension travel known as your Xmax ( Linear mechanical movement), we call it excursion in the real world. This coupled with excessive power causes the coil to heat up in the gap as it unable to move enough  to allow the heat to escape. You can also run into a distorted signal a lot faster due to the woofers suspension fighting as you try to turn the knob to 11. Which will also cause your coil to heat up very quickly.


• Ripped or torn suspension:  You can put a lot of strain on your new parts if you do not break them in. You risk tearing the suspension from the triple joint or basket landing causing mechanical failure.  You will also notice that you run into distortion a lot faster on a new stiff woofer than one that is broke in as the suspension fights back.




                *The Thiele Small parameters were measured on the HDS310-D4 above before break in and after a ~16 hour continuous play period to show us how the changes correspond to real world movement. The movement pictured above is what we call excursion. This was measured with a stroboscope which allowed us to see the cycles of the moving parts. This works by "slowing" down the reciprocation of the woofer by matching the frequency being played (40hz in this case) with a series of corresponding flashes of lights at 40 flashes per second. You can do this at home by using a 20hz tone and playing with your camera frame rate.




















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