Re: More spec sheet nonsense
It's the upper of the two spec's I flagged that's wrong, not the bottom.
101dB is an efficiency of approximately 8% (if that were from one Watt input, obviously the impedance curve affects this somewhat), so 400W electrical input should result in a ballpark output of 35 acoustic Watts, not 400W.
There's also a very slight misrepresentation of the frequency range apparent when comparing the quoted range with the graph on the spec sheet.
The max level on the graph is 105dB at approx. 310Hz and 1.8kHz, so if that's the top of the +/-3dB range, then the bottom of the +/-3dB range should be where the curve drops through 99dB. That point looks to me to be about half an octave above the 113Hz on the specs.
It does not say acoustical watt output-and that is not a standard spec that you see on spec sheets anyway. Who ever entered the data just put some wrong numbers in-watts instead of SPL. Simple as that.
And if you look at the impedance graph (most don't even show that) you will see that the average impedance is much higher than the rated 8 ohms. To me-it should be rated closer to 10 or 12 ohms (as that more realisticlly describes the overall load presented to the amplifier output). But since many people simply have no idea how to drive a loudspeaker other than 4-8-16 ohms-it is rated at the next lowest "standard" number. It is this way on many of our products.
In reality-the speaker (and i would argue all loudspeakers) have a freq response wAY out of +/- 3dB. It all depends on how much smoothing is used on the graph. Remove the smoothing and measure with enough data points and you will get a response that is all over the map-nowhere near 3dB. But nobody does that.
And if you want to use the "top" of the SPL, then the sensitivity would be rated higher-along with higher max output-the spec that is missing. But we rate speakers down around the average sensitivity-which gives lower numbers-but also gives a more realistic result that people can expect.
In my opinion the sensitivity HAS to be tied to the low freq cutoff-if not both numbers are just about useless-or at least not meaningful. So with the rated sensitivity of 101dB that gives a -3 (not -9dB like other manufacturers often like to use and "call" it -3dB) at the spec sheet numbers.
Yes there is a little dip just above the low freq rated point-but we are talking about USABLE specs. If we used more averaging then that dip would not be as low and would look better.
To me (feel free to argue) the most important thing is the -3dB point. You can easily pull down anything that is to hot-but trying to "make up" the low points puts additional strains on the loudspeaker-especially on the top and bottom of the response.
To me the really sad thing is how few manufacturers even provide a freq response-and many times it is HIGHLY smoothed so as not to look so "ragged" and people just assume that it is correct. They don't show how much smoothing is applied (that is on all of our graphs at the bottom) along with the number of samples the measurement used (at the top of the graph.
The sad trend is manufacturers only giving simple numbers and no measurements to back it up- and HOPING that the buying public will accept the numbers as fact.
So when people do present real data-it gets looked at real hard-and the gear with no data gets a "free pass".
I really wish people would put all products through the same "magnifying glass" and see what they come up with.
I won't give any names, but there are a number new products that are VERY expensive and have NO measured data (for the public anyway). Heck- several don't even give simple numbers-sensitiivty-power capacity-freq response (however that is determined), yet they want people to put down LOTS of hard cash to use them-just because they are "special".
I am sorry-but "adequate" or "ample" is not a spec number-at least to me. As compared to what? IS 20 miles per gallon "adequate" Not for a motor cycle and it is really great for a tractor trailer rig. So without other qualifiers-a simple number is almost useless.
Surely some measurements were done during the design process?
OK I'll stop now before I say what I really think---------------------------------------------
