Watts per channel needed??

[Beave]

Amps come in "sufficient" and "insufficient".

There are some edge case (or high power-demand) speakers out there where the McInosh would have been "sufficient" and the Denon "insufficient" (bass performance on my N801Ds seemed to require amps comfortable with very low ohm output). But I generally agree with your statement.

On that note, I also heard a different Magnolia salesperson tell a customer that the advantage of a high(er) power amp/receiver wasn't in its ability to play louder cleanly, but that it plays cleaner at low levels.

 

[JerryLove]

What is a more difficult load for an amplifier 30 hz at 100 db or 600 hz at 100 db hooked up to the same speaker?

Assuming constant sensitivity; that would depend on the impedance of the given speaker system at each of those frequencies (and how you would like to define "difficult")

 

[JerryLove]

On that note, I also heard a different Magnolia salesperson tell a customer that the advantage of a high(er) power amp/receiver wasn't in its ability to play louder cleanly, but that it plays cleaner at low levels.

I had one that didn't know (and yet argued) amplifier class, and insisted that Emotivas amps were Class D (I believe they have since added a class D to their lineup, but they had not then)

 

[HTfreak2004]

Not enough info given to answer the question. Not to mention that the question is worded very strangely.

Explain why the input signal (frequency) has an influences over the impedance a speaker places on an amp?

If the signal of a low frequency say 100 hz lowers the impedance placing more demand on an amp from say 8 ohm to 4 ohm or 2 ohm what does that do to the wattage being produced by the amp? Does it stay constant, go up or down?

 

[Beave]

The signal doesn't lower the impedance. The impedance of a speaker is what it is (I hate that saying, but it applies here). Yes, the impedance magnitude and phase vary with frequency, but it's semantically very odd to say that the frequency influences the impedance. It does not influence or change it. Impedance changes with frequency but not because of frequency.

 

[HTfreak2004]

Assuming constant sensitivity; that would depend on the impedance of the given speaker system at each of those frequencies (and how you would like to define "difficult")

When you stated the “impedance of a given speaker system” are you implying that the impedance never fluctuates?

 

[Beave]

Assuming constant sensitivity; that would depend on the impedance of the given speaker system at each of those frequencies (and how you would like to define "difficult")

Exactly - would need to know frequency response of the speaker AND its impedance at those frequencies.

 

[Beave]

Explain why the input signal (frequency) has an influences over the impedance a speaker places on an amp?

If the signal of a low frequency say 100 hz lowers the impedance placing more demand on an amp from say 8 ohm to 4 ohm or 2 ohm what does that do to the wattage being produced by the amp? Does it stay constant, go up or down?

Still need more info, such as the amplitude of the signal being amplified.

You're asking strange questions with EE terms but not in ways that an EE would ask them. Are you an EE?

 

[Beave]

When you stated the “impedance of a given speaker system” are you implying that the impedance never fluctuates?

If he were implying that, he would have had no need to write "...the impedance of the given speaker system at each of those frequencies ..."

 

[JerryLove]

When you stated the “impedance of a given speaker system” are you implying that the impedance never fluctuates?

That's an ambiguous question.

The impedance curve of a given speaker system is relatively constant. There are variances caused by, say, temperature; but these are generally negligible.

 

[JerryLove]

Explain why the input signal (frequency) has an influences over the impedance a speaker places on an amp?

You realize, I hope, that this reads as very condescending.

If the signal of a low frequency say 100 hz lowers the impedance placing more demand on an amp from say 8 ohm to 4 ohm or 2 ohm what does that do to the wattage being produced by the amp? Does it stay constant, go up or down?

That's really badly worded. (and again, condescending as it's rhetorical yet looking for a response)

You are asking what the relationship in a speaker system is between wattage and impedance.

As we've already explained to you, sensitivity is voltage.

If your resistance drops while your voltage remains constant than your amperage (current) increases; which in turn increases both VA (literally volts X amps) and Wattage (power draw).

 

[HTfreak2004]

That's an ambiguous question.

The impedance curve of a given speaker system is relatively constant. There are variances caused by, say, temperature; but these are generally negligible.

a

You realize, I hope, that this reads as very condescending.


That's really badly worded. (and again, condescending as it's rhetorical yet looking for a response)

You are asking what the relationship in a speaker system is between wattage and impedance.

As we've already explained to you, sensitivity is voltage.

If your resistance drops while your voltage remains constant than your amperage (current) increases; which in turn increases both VA (literally volts X amps) and Wattage (power draw).

See the problem with asking any question to find out what someone else means Can and usually does make that person feel patronized.

If any of you guys feel that way it’s because literally tonight all that gets thrown out there is 2.83v with no reference to the input signal and how that affects the operating impedance of any said speaker system!

For the record JerryLove, if anyone condescended to anyone tonight that was you! Not only did you speak for Beave on several occasions tonight you also decided I was condescending to him any chose to act as a mediator!

So Beave if your reading thanks for sharing your thoughts tonight!

 

[Verdinut]

And what changes the impedance?

Cone speaker impedance, except for the case of air motion transformer tweeters, changes from frequency to frequency and is modified by the magnetic field caused by the movement of the voice coil within that magnetic field.
Some speakers with a nominal impedance of 8 ohms might have an impedance of 8 ohms at 400 Hz but show an impedance of only 3.5 ohms at 100 Hz. If the amplifier has a weak power supply, it will not be able to handle that low impedance at 100 Hz where there is more power demand than at higher frequencies.

 

[HTfreak2004]

Cone speaker impedance, except for the case of air motion transformer tweeters, changes from frequency to frequency and is modified by the magnetic field caused by the movement of the voice coil within that magnetic field.
Some speakers with a nominal impedance of 8 ohms might have an impedance of 8 ohms at 400 Hz but show an impedance of only 3.5 ohms at 100 Hz. If the amplifier has a weak power supply, it will not be able to handle that low impedance at 100 Hz where there is more power demand than at higher frequencies.

I agree!

 

[Beave]

If any of you guys feel that way it’s because literally tonight all that gets thrown out there is 2.83v with no reference to the input signal and how that affects the operating impedance of any said speaker system!

The input signal *IS* 2.83 volts - that's what is sent to the speaker from the amp. The frequency is swept, from 20Hz to 20kHz, but the voltage amplitude of the signal remains constant.

The *current* will change as the speaker impedance varies versus frequency, and therefore the wattage outputted by the amp will also vary over the sweep.

What are we even arguing about?

 

[Beave]

Cone speaker impedance, except for the case of air motion transformer tweeters, changes from frequency to frequency and is modified by the magnetic field caused by the movement of the voice coil within that magnetic field.
Some speakers with a nominal impedance of 8 ohms might have an impedance of 8 ohms at 400 Hz but show an impedance of only 3.5 ohms at 100 Hz. If the amplifier has a weak power supply, it will not be able to handle that low impedance at 100 Hz where there is more power demand than at higher frequencies.

Depends, of course, on how loud (how much voltage & current) is being demanded from the amp. At modest levels, most amps & receivers will be able to handle such a load with no problems. As you play louder and louder, however, different amps will crap out (that's my technical term!) at different levels.

 

[JerryLove]

a

Definitely "a". I'm glad we can agree on something.

See the problem with asking any question to find out what someone else means Can and usually does make that person feel patronized.

It's more in your phrasing than the fact that you asked a question. Your questions are rhetorical in a way that condescends.

For some counter examples: look at the questions you have been asked on this thread by several posters and not answered.

If any of you guys feel that way it’s because literally tonight all that gets thrown out there is 2.83v with no reference to the input signal and how that affects the operating impedance of any said speaker system!

So, you are blaming the audience for feeling that your statements are condescending because our statements forced you to be condescending?

Just wow.

For the record JerryLove, if anyone condescended to anyone tonight that was you! Not only did you speak for Beave on several occasions tonight you also decided I was condescending to him any chose to act as a mediator!

And now you are just belligerent.

You don't appear to have any idea what you are talking about, and even less idea what we are telling you in response (it might tell you something that the rest of the thread has consensus on the issue that you keep talking in circles about).

You are the proverbial pigeon playing chess.

 

[SPLaddict90]

ahhh impedance rise the invisible C**T.

 

[PENG]

Right, I knew that too and still typed 1 watt. Oops.

I would disagree slightly with hd, just slightly though. 2.83V/m is technically better/more electrically correct, but the W/m is better in one way. That is, if the manufacturer specified its speaker's sensitivity 88 dB/w/m, then you know it is 1W for 88 dB output at one meter regardless of the impedance.

That popular calculator we linked everyday twice on Sunday is based on W/m, so yes the user would have to make adjustments for speakers that have nominal impedance other than 8 ohms. I think I posted a conversion table recently for that purpose.

 

[PENG]

I called him a design engineer because I was quoting his title from the business card he gave me.

I don't know about the US, in Canada one can be sued for that if not actually a licensed engineer lol..