Any way to manipulate the overal impedance(ohms)?

[BnGRacing 10+ year member]

The higher the impedance the cooler any amp will run. Ure not to savy r ya?

EDIT: 4 ohms is easyer on a system then 2 right? Correct me if im wrong

Some D-Class amplifiers use a topology that actually causes them to run HOTTER with impedances over 4ohm. MTX comes to mind as one of those amps. So I'm at least a bit more 'savy' than your grammar, spelling, and/or literacy.

 

[BnGRacing 10+ year member]

I actually agree that shorting the other coil will have an effect. Think about the magnetics, if you leave it open it will generate a voltage at the terminals, if you short it, it should just be inert...I'm just theorizing based on what I remember from my electromagnetics course though, lol

That is correct and you can do this simple test for yourself.

Tap on a subwoofer's cone with the coil shorted and not shorted. Even then, with zero power going to it, the sub will 'sound' different in both instances. Shorting the coil is a trick to raise the Q of a woofer and is very handy for IB installs.

 

[duanebro 10+ year member]

Adire has a white paper on this.

web.archive.org/web/20061004092351/http://adireaudio.com/TechInfo.htm

 

[JoshC 10+ year member]

Some D-Class amplifiers use a topology that actually causes them to run HOTTER with impedances over 4ohm. MTX comes to mind as one of those amps. So I'm at least a bit more 'savy' than your grammar, spelling, and/or literacy.

lol dont be butthurt.... And i dont believe that, do u have a thread or sum kind of proof where this has happened? Ive just never heard that, not trying to call you out

My spellin bothern ya? FUCK you, im from texas

 

[ahole-ic]

It has no effect. It's easily proven. You can't tap on a woofer and know the difference. That was silly to even say. Nobody can take you seriously now guy.

"Qes The driver's Q at resonance (Fs), due to electrical losses; dimensionless. "A measurement of the control coming from the speaker's electrical suspension system (the voice coil and magnet). Opposing forces from the mechanical and electrical suspensions act to absorb shock.""

Now since the coil has nothing put into it, it can't actively oppose the fixed magnet in the motor. A coil in a magnetic gap does indeed generate a voltage. That voltage will have the same polarity as the magnet. So, shorting the coil would actually cause the coil to at all times be attracted to the fixed magnet which would hinder the performance of the woofer.... but that voltage is so tiny it would not at all matter. If it weren't tiny, since it is dc current, it would blow the coil. This is all simple and basic physics as well as electronics. You guys have to start using your heads.

 

[JoshC 10+ year member]

It has no effect. It's easily proven. You can't tap on a woofer and know the difference. That was silly to even say. Nobody can take you seriously now guy."Qes The driver's Q at resonance (Fs), due to electrical losses; dimensionless. "A measurement of the control coming from the speaker's electrical suspension system (the voice coil and magnet). Opposing forces from the mechanical and electrical suspensions act to absorb shock.""

Now since the coil has nothing put into it, it can't actively oppose the fixed magnet in the motor. A coil in a magnetic gap does indeed generate a voltage. That voltage will have the same polarity as the magnet. So, shorting the coil would actually cause the coil to at all times be attracted to the fixed magnet.... but that voltage is so tiny it would not at all matter. If it weren't tiny, since it is dc current, it would blow the coil. This is all simple and basic physics as well as electronics. You guys have to start using your heads.

And thats y i wouldnt argue with ecrack hahahhaha

 

[BnGRacing 10+ year member]

It has no effect. It's easily proven. You can't tap on a woofer and know the difference. That was silly to even say. Nobody can take you seriously now guy.

Try it and report back //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Seriously...go ahead and hear if there's a noticeable difference. The test with the 'shorted' coil will usually sound tighter. It sounds ridiculous, no pun intended, but it happens. The difference between a shorted coil and leaving one alone is probably best heard in IB applications where a higher Q is usually preferred.

 

[ahole-ic]

Try it and report back //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Seriously...go ahead and hear if there's a noticeable difference. The test with the 'shorted' coil will usually sound tighter. It sounds ridiculous, no pun intended, but it happens. The difference between a shorted coil and leaving one alone is probably best heard in IB applications where a higher Q is usually preferred.

I have.... there isn't.

 

[duanebro 10+ year member]

Try it and report back //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Seriously...go ahead and hear if there's a noticeable difference. The test with the 'shorted' coil will usually sound tighter. It sounds ridiculous, no pun intended, but it happens. The difference between a shorted coil and leaving one alone is probably best heard in IB applications where a higher Q is usually preferred.

Umm, you are both a bit off. I posted a link to Adire's white papers. You should look at it.

Ecrack - You stated that the coil generates a small current, this is true, but it does have an effect. It effects the Qes, it brings it back to the same as using both coils.

BnGRacing: I couldn't hear the difference on the sub I just tried, but it is a high q driver, so I would think it would have less of an effect. As far as shorting the coil, it lowers the Q, (if the other coil is being used) In a ob a resistor across the second vc will vary the Q.

Other things of to note, efficiency decreases by 6db. Power handling decreases a little. Around 25% is a safe guess.

 

[bubbagumper6 5,000+ posts]

It has no effect. It's easily proven. You can't tap on a woofer and know the difference. That was silly to even say. Nobody can take you seriously now guy."Qes The driver's Q at resonance (Fs), due to electrical losses; dimensionless. "A measurement of the control coming from the speaker's electrical suspension system (the voice coil and magnet). Opposing forces from the mechanical and electrical suspensions act to absorb shock.""

Now since the coil has nothing put into it, it can't actively oppose the fixed magnet in the motor. A coil in a magnetic gap does indeed generate a voltage. That voltage will have the same polarity as the magnet. So, shorting the coil would actually cause the coil to at all times be attracted to the fixed magnet which would hinder the performance of the woofer.... but that voltage is so tiny it would not at all matter. If it weren't tiny, since it is dc current, it would blow the coil. This is all simple and basic physics as well as electronics. You guys have to start using your heads.

Wouldn't it generate an AC waveform equal in frequency to the input of the other coil? If the coil is moving back and forth through the magnetic field it should be sinusoidal...

 

[bubbagumper6 5,000+ posts]

And thats y i wouldnt argue with ecrack hahahhaha

Even the smartest of men are wrong on occasion. If I feel someone is wrong, I'll point it out. Also, I don't know about the other guys but I'm not trying to argue, simply discuss, which is what a discussion board is for //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[ahole-ic]

Wouldn't it generate an AC waveform equal in frequency to the input of the other coil? If the coil is moving back and forth through the magnetic field it should be sinusoidal...

The sinusoidal portion of your statement is incorrect. When a coil is in a fixed magnetic field, the current generated in it is proportional to the polarity of the magnet. Whether or not it is moving doesn't matter. It could not generate a sine wave. It would merely vary the intensity. The inactive coil would indeed reflect the active coil, although that signal too would be incredibly weak. I guess I will shoot a vid in a little bit to put this to rest. Measuring the voltage in the inactive coil should do the trick for anyone who has any electronics knowledge.

 

[wenn_du_weinst 10+ year member]

it may change inductance, wiring in parallel over series changes inductance.

 

[bubbagumper6 5,000+ posts]

The sinusoidal portion of your statement is incorrect. When a coil is in a fixed magnetic field, the current generated in it is proportional to the polarity of the magnet. Whether or not it is moving doesn't matter. It could not generate a sine wave. It would merely vary the intensity. The inactive coil would indeed reflect the active coil, although that signal too would be incredibly weak. I guess I will shoot a vid in a little bit to put this to rest. Measuring the voltage in the inactive coil should do the trick for anyone who has any electronics knowledge.

If it's not moving, it won't generate a voltage...

 

[ahole-ic]

If it's not moving, it won't generate a voltage...

So how do transformers work?