21 replies to this topic

[Bassaholic]

ProClass, on Jun 26 2006, 10:47 AM, said:

Well…..
By only connecting one coil you will have added mass to the cone.

No, the mass was always there in the dual coil, the only difference being that the other coil is no longer in the circuit, so what happens to the Qes?

Quote

The little piece of wire? Got me. Open or Closed the un-connected voice coil is not in circuit and wouldn’t play any electrical role.

No. I'm guessing you're a hands on kinda guy, so maybe you'll want to measure it?



As for the diode, well you could use one, it'd be interesting (if you're like me and think distortion is interesting), but not terribly useful.

Edited by Bassaholic, 26 June 2006 - 11:07 PM.

[~thematt~]

I know about this one, but have never tried it

You change the Qts of the driver itself. Infact, if you replace the cable you use to short the other coil with a resistor (as in a variable) you can 'dial-in' your desired response of the woofer.

Put it in a sealed box, hook up your dial, and you can CHANGE the response of that one sub, to whatever your heart desires.

[Bassaholic]

Have an e-cookie.

The answer to the first question is the Qes will double, so the resulting Qts will be a little bit less than 2x the initial Qts. (depending on the Qms as Qts = (Qms x Qes) / (Qms + Qes ) )

The answer to the second question, is the Qes will be double as before, however the other coil will increase the damping of the coil (dramatically reduce the Qms), so the Qts will be basically the same as if you hooked up both coils to the amplifier. So if you hooked up a variable resistor, you would be able to adjust the Qts. From the level it was at when both coils were hooked up, to a little bit less than twice that amount.

If you add resistance in series with the woofer, this will increase the resistive losses (the other resistive loss being the voice coil resistance), thus increasing the Q. But obviously this method is not practical, since the resistor will waste a lot of power out as heat (requiring a very chunky resistor)...

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Edited by Bassaholic, 27 January 2007 - 12:35 PM.

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[ProClass]

Makes sense.... kind of.
I'm going to try this out the first chance I get.
But, I am not that confident the results will be what the idea suggests.
Cheers

[Kev]

I'm guessing finding/buying a resistor that can handle that sort of power, you may as well just build the sub initially to suit your needs?

[Bassaholic]

Kev, on Jun 28 2006, 06:11 PM, said:

I'm guessing finding/buying a resistor that can handle that sort of power, you may as well just build the sub initially to suit your needs?

In the example, the resistor is only in series with the woofer if you wish to raise the Qts of the SVC driver. (Which is not practical as you have guessed.) In a tube amplifier, the output transformer has the same effect (lowering the damping factor).

But in the main example, we were talking about dual voice coil woofers and the resistor will not be in the same circuit as the amplifier, so the power handling of the resistor doesn't matter much.

Edited by Bassaholic, 27 January 2007 - 12:34 PM.

[ProClass]

Well, I tested the idea.
The testing was 100% subjective with respect to response.
Yes, there is an auditable difference in the speakers frequency response. Very sublte but a change none the less.
I can not say if the changes I heard were positive or not. I think I need to hear this in a car to decide that.
I want to do some T/S testing and a little more research into this idea before drawing conclusions.
So far, I think that the idea could yield some good results but I question if they suit the car audio enviroment.