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How important is the efficiency of a speaker to you?

I went to an audio meeting recently and heard a couple of good sounding speakers. These speakers were not inexpensive and were well built. Problem is that they also require a very large ss amp upstream to drive them. Something that can push a lot of current, which pretty much rules out most low-mid ( maybe even high) powered tube amps. When I mentioned this to the person doing the demo, i was basically belittled, as he felt that the efficiency of a speaker is pretty much irrelevant ( well he would, as he is trying to sell these speakers). The speaker line is fairly well known to drop down to a very low impedance level in the bass regions. This requires an amp that is going to be $$$, as it has to not be bothered by the lowest impedances.

Personally, if I cannot make a speaker work with most tube amps on the market, or am forced to dig deeply into the pocketbook to own a huge ss amp upstream, this is a MAJOR negative to me with regards to the speaker in question ( whichever speaker that may be). So much so, that I will not entertain this design, regardless of SQ.

Your thoughts?

128x128daveyf
herman
2,263 posts
 

If you look into this a bit further you will discover that these other waves are combinations of sine waves, and there are no musical signals which have an instantaneous rise time. If you put any musical signal through a spectrum analyzer you will see it broken down into these various frequencies.

https://mathworld.wolfram.com/FourierSeries.html

As the article you dismiss states, once the slew rate of the amplifier is high enough that it can amplify the highest required frequencies without distorting them (it is not slew rate limited) then a higher slew rate does not matter.

I’ll leave it to you to dig in and educate yourself about this, since instead of trying to understand slew rate, it appears you are only interested in proving you were right despite the fact what you initially stated is undeniably incorrect.

I’m done with it. Good luck in your journey.

 

 

toddalin's avatar
toddalin
294 posts
 

But to "composite" a square wave from sine waves would take sine waves way up into the ultrasonics and where would that put the slew factor???

A Hammond uses exactly the technique to which you allude. But it never achieves anywhere near a true square wave.

Actually, one could make the argument that a sine wave is just a bunch of square waves with short duty factors and their amplitudes arranged in a "wave" pattern. But again, how many would it take to achieve the true sine pattern?

No musical signals with an instantaneous rise time?

If you play a square wave and the amplifier produces 17v/ms and the speaker needs 17 volts to reach the desired volume, it can occur in no less than 1 ms.

If the other speaker is 10 dB more efficient it only needs 5.4 volts to play the same volume so it can occur in no less than 0.32ms.  That's the math.  Whether the speakers can actually keep up is another matter/discussion.

Regarding being right... it seems that you read one thing and think it applies to all cases..., and obviously it, and therefore you, must be right. Show us something where slew factor is discussed in relation to other wave forms as they actually exist. You are only presenting one side of the argument.

deep_333
1,520 posts
 

Herman = +150

Toddalin = -165

 

invalid
1,226 posts
 

There is a difference between sensitivity and efficiency.

ditusa's avatar
ditusa
1,898 posts
 

Sensitivity vs. Efficiency see below page one paragraph C:

Mike

https://www.lansingheritage.org/html/jbl/reference/notes/tech1-3a.htm

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