Re: what does it mean to "break in" a speaker?

Peter Alerich wrote:
On Wed, 12 Sep 2007 20:26:13 -0400, TD Madden
<tdmadden48-no@xxxxxxxxxxxxxxxx> wrote:

Thanks for the good article from TW.

It's not noted in the article and there are some uninitiated folks
who might not equate transformer/filament transformer with AC so I'll
go ahead and say it - don't connect a DC source to your speaker. Only
use an AC source for this break-in procedure.

There, I said it. I feel better. :)
Peter


From Ted Weber's "Let's Talk Speakers":

"...OK, on to 'breaking in' a speaker. If you really want to speed up the breaking in period, the easist method is to connect the speaker to a filament transformer. Having said that, let's look at the precautions you need to take. Since you will be driving the speaker with a steady state signal, you don't want to drive it at its rated power or it will burn up the voice coil. 1/3 power rating is a safe figure to use. So, let's say you have a 50 watt speaker and it is 8 Ohm. 1/3 power is about 17 watts, and at 8 Ohm, that works out to be around 11.5 volts. Using a 12.6 volt transformer will put 20 watts into the speaker. I wouldn't have a problem with that in our products, but just to be safe, you might want to go with a 6.3 volt filament voltage, which will put about 5 watts into your speaker. Another option is to use a variac into the primary side of the 12.6 volt filament transformer and dial in the voltage you want on the secondary. That way, you can dial in the 11.5 volts we originally calculated at the 1/3 power level. I'd also suggest performing the operation in a garage or closet, because listening to the loud 60hz hum from the speaker will grate on your nerves very quickly. Also, if you leave the speaker out of the cabinet, the rear radiation of the speaker will cancel alot of the front radiation and reduce the noise. You need to lay the speaker face up though, so the cone can move as much as possible since the whole idea of this operation is to loosen up the cone and spider. Laying the speaker face down would trap air between the cone and the surface of the table and restrict cone movement. You're going to be surprised how much the cone moves and how loud the speaker is, even at 1/3 power.
Here's the math for determining the correct voltage to use in case you have a different wattage and impedance rating than our example above:
1. Take the power rating of the speaker and divide it by 3.
2. Take that number and multiply it by the speaker's Ohm rating (4, 8, or 16)
3. Use your calculator to find the square root of that number.
4. The result is the voltage you need to use to drive the speaker at 1/3 its rated power.
As a matter of fact, I use an 120VAC to 9/11/13VAC transformer for AT&T answering machines I picked-up at RatShack. Works just fine.
.

Relevant Pages

  • Re: Switching power supplies question.
    ... The high voltage might be full wave ... The step down transformer is usually an E-E core or ETD ... If the 6.3VDC output was most of the power it would make sense ... switching action of the rectified 115 or 230 volt AC input? ...
    (rec.radio.amateur.homebrew)
  • Re: AC to DC Transformer
    ... only yields 6 watts of power for both the radio/tape/cd circuit and the ... > The problem I have is that I need the correct AC to DC transformer. ... > After testing several with 12 volt outputs, ... > need something with a higher amp rating? ...
    (sci.electronics.basics)
  • Re: 1000V input, 5V output, 5W, SMPS reference design needed
    ... > My needs and concerns are similar to those described by Doug McNutt 7 ... > Subject: micropower 1000V MOSFET power ... I can't reach my 48 volt goal. ... > I need a lot of isolation in the transformer for reasons of personal ...
    (sci.electronics.design)
  • Re: what does it mean to "break in" a speaker?
    ... are you supposed to play the amp at a low level for a while until you crank it? ... Since you will be driving the speaker with a steady state signal, you don't want to drive it at its rated power or it will burn up the voice coil. ... I wouldn't have a problem with that in our products, but just to be safe, you might want to go with a 6.3 volt filament voltage, which will put about 5 watts into your speaker. ... You need to lay the speaker face up though, so the cone can move as much as possible since the whole idea of this operation is to loosen up the cone and spider. ...
    (alt.guitar.amps)
  • Re: Current Transformer to 0-10 Volts
    ... I was looking at analog.com at some of their power ... sell current transducers that do this alreay, but I want to make about ... If you used your original 10:1 ratio, the ten volt drop would reflect ... the current transformer output, but that's not a wonderful idea from ...
    (sci.electronics.design)