Sensitivity 86 v 90

"Overcoming misinformation

One misleading piece of information with which our customers are often provided is sensitivity. This specification is commonly misrepresented as "efficiency" which it most certainly is not. Loudspeakers are terribly inefficient and it is likely that virtually no consumer has ever been given an actual efficiency specification. The most efficient loudspeaker designed to date was the Altec Lansing Voice of the Theater, which had an efficiency rating of approximately 3.6%. No loudspeaker manufacturer would ever publish an efficiency specification because it would discourage and mislead consumers. Be clear on one point: sensitivity and efficiency are not the same thing. Even when using a solid state amplifier, one cannot necessarily equate high sensitivity to high efficiency - the physics are simply more complex than many manufacturers, and sadly reviewers, lead us to believe.

Instead of efficiency, loudspeaker manufacturers provide a sensitivity specification. This figure is supposed to indicate how loud a speaker will play when fed one watt of power, or 2.83 volts, listening from one meter away. The problem with this measurement is that the conditions under which it is to be recorded are not well defined and hence the figure does not provide a consistent "apples to apples" point of reference. For one thing, the input sensitivity (gain) of the amplifier used to measure the sensitivity is unknown and unspecified. More importantly, while the specification calls for measurement at one meter away, the conditions of the listening room are not defined. It is not clear whether measurement is to occur in an anechoic chamber, a concert hall, a coat closet, or a gymnasium. Each of these rooms will yield remarkably different sensitivity readings at one meter from the speaker.

The most important lesson to learn from the above discussion is that for the purposes of determining tube-friendliness, sensitivity is essentially meaningless. Many tube gurus insist that one must use speakers with sensitivity ratings of 90 db or higher. This is simply not true. Many speakers with high sensitivity ratings are poor choices for tube amps, just as many speakers with low sensitivity ratings often work quite well. Why is this so? Read on…"

https://www.dhtrob.com/overige/tubefriendly_lsp_en.php

I went from JBL 4319 monitors rated at 92db efficiency, 6ohm nominal, 4.7ohm at lowest point to Atalante 3 monitors rated at 87db efficiency, 6ohm nominal, 4.4 ohm at lowest point and only have to increase volume 1- 1 1/2 db for the same results. Some reviewers are using 15 watt tube amps and getting wonderful results.

Even at the old normal listening level, I’m hearing more than with the older speakers. Just the SPL is lower. Without the cabinet and crossover, the drivers in the Atalante 3 are rated at 91db efficiency on their own. Turning the wick up to get the same scale and impact requires just a db or so to get there and it sounds more convincing in some respects but can sound too loud. Go figure.

I wished I had bookmarked a review where it was explained how efficiency is such a misunderstood measurement since no two speakers rated the same, perform the same and those that vary some will perform the same.

All the best,
Nonoise

@lloydc Wrote:

  I do like having 90 db efficiency, 

I like having 2.7% efficiency and 96 dB sensitivity! 😎

Mike

Thanks for the explanations!

My integrated amp (Rogers EHF 200 Mk 2) has 40 db of gain.  The volume control is turned up much less with signal from the dac, than while using the phono preamp, which I presume  means the dac has higher output; but (as I understand it) the gain from the phono preamp can be increased by switching the driver 12AU7 tubes for 12AX7's, if necessary.  Which, maybe I should do anyway, as @Soix and @tomcarr imply.

@lloydc Wrote:

My integrated amp (Rogers EHF 200 Mk 2) has 40 db of gain. 

That is a nice amp, you have plenty of gain. What phono preamp do you have?

Mike