Is there a plan to submit the Aspens to TAS or Sterophile for review? I’ve relied heavily on these guys for a lot of years and in this case a decent review is pretty important. John Atkinson’s measurements are usually trustworthy and may answer a lot of questions.
A pretty good primer on basic speaker measurements is John Atkinson’s talk an RMAF about 10 years ago. He gets into sensitivity about 3 minutes in:
One thing that you’ll note is that out of all of the hundreds of speakers that he’s measured, the median/mean sensitivities are 88 dB and 85 dB. If you flip the boundary switch on an FR-30, you gain nearly 2 dB in the mid/treble from the 87 dB spec. Would I say that this is average sensitivity? Yes.
Do manufacturers overstate this number quite often, playing a bit of a specsmanship game? Yes! Some manufactures are worse than others regarding the accuracy of this spec, which seems to feed the confusion around it.
Is higher always better (as the OP suggests)? Why would a designer choose a higher/lower sensitivity for a given design? The laws of physics are pretty simple about all of this and there are simple design tradeoffs. Feel free to google “hoffman’s iron law”.
It states that the efficiency of any speaker system is directly proportional to the enclosure volume and the cube of the low frequency cutoff. Basically, you can have two out of three - small box, deep bass extension and high efficiency. To put some more dimensions to it, for the system to play and octave lower (20 hz vs 40 hz) at the same efficiency, the enclosure volume requirements go up by 2^3 for a factor of 8 times the size. Conversely, if you want the enclosure half the size for a given low frequency extension, the efficiency has to be reduced by half. We chose what we feel are the optimum balance of these three factors for this design. Other companies may differ in their approach and which of these factors they are prioritizing, but by John Atkinson’s presentation, you’ll find that most speakers are rather similar in sensitivity (with some notable outliers).
Note the careful use of sensitivity and efficiency. When speaking about sensitivity we are talking about the output with a fixed voltage. Most amplifiers are voltage sources and so will put out more power into lower impedances. However, this places larger current demands on the amplifier and performance of amplifiers often gets much worse on difficult/reactive loads.
Wilson audio was mentioned earlier in this thread as having rather high voltage sensitivity of around 91 dB/2.83V. They are great speakers but are often designed with a punishingly low impedance dropping to 1-2 ohms in the bass, with sometimes a significantly reactive load (looking at things like an EDPR rating, their effective impedance can be 1 ohm). For each halving of impedance, you gain 3 dB of voltage sensitivity and so you can see that the real efficiency of these speakers isn’t particularly high. Though the voltage sensitivity is rather high - the amplifier is called to deliver more watts in the form of current demands.
As Paul mentions, the FR-30 only varies from 3.5-5.5 ohm from 25 Hz and up) and is 5 ohm in the bass, making it easy to drive.
Sound pressure level in room is more complex than your calculator suggests. The room acoustics and seating distance play a significant role in this. Page 104 of Ear Geddes “premium home theater” has a pretty good description of direct vs. reverberant fields in listening rooms.
http://www.gedlee.com/downloads/HT/Home_theater.pdf
Basically, the more “live” the room and wider directivity the speaker, the more sound pressure is sustained in the room. Essentially, sound doesn’t actually fall of at 6 dB per doubling of distance.
Additionally, many high sensitivity speakers sacrifice not only bass extension in their design but also total bass output capability because the most significant physical parameter driving sensitivity on the woofer level is mass and the mass of the coil itself is a large factor on a high excursion driver. Essentially, you can cut the coil length and increase sensitivity of a woofer but the amount of excursion and bass output that the woofer has (and air that it can displace) can be dramatically lowered. Again, this is an engineering compromise that isn’t captured in a single number. Sensitivity is not equal to output capability.
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It’s refreshing to hear from a designer who is willing to lay it all out there.
Thanks, Chris.
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Rarely I learned so much in so little time!
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Thank you, Chris!
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Well done Chris !!! 
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So, what will it take to push 105dB out of these puppies?
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In the current list of Stereophile Class A LF Limited speakers, of the eight full size (not stand-mounted, which are usually lower sensitivity) passive speakers in that list, the mfg sensitivity ratings range from 86-93, with Joseph Audio not listing a spec.
In particular, for the seven that do: 93, 90, 86, 90, 87, 91, 87. So 87, while toward the low end of that small sensitivity sample, is not outside of the window, fwiw.
I think using 10-year old data and including standmount speakers in the sample (which presumably JA does) isn’t so relevant to the pertinent question of floorstanding, modern speakers. Sensitivity spec’s have been trending upward over time I believe.
Well, I think that I’ve surprised a couple of coworkers when showing off the dynamics of the FR-30.
I was playing the FR-30 full tilt on a pair of BHK 300 amps for our director of engineering, Barry. It was an EDM track from Feynman off of Quobuz. He jokingly asked “have you ever killed someone with these”?
Our international sales manager Travis remarked “I’m glad that you were controlling the volume” as he wouldn’t have turned our prototypes here up that loud for fear of breaking them, not realizing how well they hold together at high SPL.
I think that people are going to be happy about the dynamic headroom of these.
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Just if this doesn’t take too much of your time:
Active speakers usually sound like a passive speaker with high efficiency or huge power amp resources, as they sound very immediate, direct, fast, controlled even with smaller internal amps. I guess this is due to the lacking passive crossover.
Is there an equivalent for the „efficiency“ or power demand of an active speaker compared to a passive? How much less watts is needed for an internal amp to drive an active speaker compared to an average passive one? Hope this thinking is not too stupid.
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Very encouraging…
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Great points, but it’s misleading in that you’re taking about woofer/enclosed/baffle speakers. Horns for example, do not behave the same way, so it’s unfair to say that a high sensitivity speaker will not perform as well as a low sensitivity speaker in the lower octaves.
Plus, a very live reverberant room is not exactly the ideal for any speaker system. Nor would, I assume, you want to corner load these speakers, which would increase sound level output.
Someone above asked what power will it take to drive the FR30 to 105dB. I haven’t seen an answer yet, other than the calculator I posted.
Hmmm. Looks like an answer to me. Or perhaps you’d like to design and sell your own speakers?
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“Aspen FR-30 Massive Power Required” ??? What I learned from Chris and Paul is FR-30 does not require massive power, and that is all I really care about.
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A solid sensible approach.
The speaker is of average sensitivity with a benign impedance curve. It will be easy to drive and capable of deafening volumes driven by your favorite PS Audio amp.
This is all I need know. 
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None of the ‘massive power’ statements tie with my real world experience w an 87db speaker. Sure you need power - but it is room dependent. … but this whole argument about 105 db seems odd to me …as if this is somehow ‘the’ measurement? My experience ties with most others that have spoken here. God - let them come out …let people listen. Oh and btw - they aren’t horns. So what.
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Where does Chris say this?
And now you’ve switched to horn speakers.
It seems you are trying to rationalize your argument for the sake of being right.
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I am an actively performing orchestral musician (played again today).
I recently performed Verdi’s Requiem for four soloists, double choir and orchestra including 3 flutes, 2 oboes, 2 clarinets, 4 bassoons, 4 French horns, 8 trumpets, 3 trombones, cimbasso (to replace a tuba which Verdi hated) and full strings. Sections are as loud as a full orchestra gets and may reach 105dB in the front row (I do not know, but the front row is not where you want to be sitting in any event - bad sound integration, sound is going over your head, bad visuals, etc.).
I do not care to drive an audio system at these volumes. It can harm your hearing (many orchestral players and conductors have hearing loss) and unpleasantly loads any room outside of a hall. Yuck.
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He says it throughout. Read it again. He’s talking about characteristics of “traditional” speakers: drivers in a box, for lack of a better description. What he says does not apply to other speaker designs. That was my point.
I was seriously interested in these, but based on this discussion- especially the very strange defensive excuses I’m hearing from PSA, I’ll put my money elsewhere.
No, Elk. Wishing something isn’t true doesn’t make it false.
Art’s Stereophile comment, that Paul quoted and I shared above, talked about 107dB in row H. Not the first row. And not 104 dB.
My father is a professional violinist and I’ve been to plenty of concerts.
It’s humorous that such a bastion of truth is attempting to be dismissed. I will say it one last time:
If your goal is to reproduce live music, and that must be undoubtedly anyone’s goal if they are contemplating spending these sums on “hifi”, then your system must be able to reproduce live music accurately. A big part of that is not distorting or compressing peaks.
Don’t focus on “I never to listen at those levels, so this is not for me”. Wrong. You do listen at those levels. We all do. Because at an average of 80dB, your content will have peaks exceeding 100. That could be an explosion, a violin, or a myriad of other sources. If your system crushes that, either through distortion or clipping or roll-off, you’re not reproducing the sound as the artists and engineered intended. Simple. This is 1+1=2 guys.