In short Nice One continues to be wrong. It's a shame we were conned by him for so long. So where to start...
Nice One has the fundamentals wrong. SPL is ALWAYS 20log, not 10log. You only use 10log when calculating dBm and we are talking about dBspl - honest mistake? Nice One should be aware that dBm is commonly used in RF power calculations and sometimes to describe audio amplifier gain, but not in this context.
Secondly, mobile phone speakers rarely handle more than 0.5-0.7Watts peak power and about half that value continuously. But this and the other cited “comparative specs” are not subject to interpretation as there are published product specifications available to all.
For example a few years back Knowles acquired the micro speaker unit from NXP (Phillips), thus overnight becoming the 3rd largest global micro speaker manufacturer (behind AAC, Foster, and sometimes in front of Goertek). Here is a link to a typical micro speaker sold to the smartphone industry:
http://www.knowles.com/eng/content/download/3213/38271/version/4/file/2403 260 00001 Donau.pdf
Not a fan of Knowles, then here is a link to Foster’s micro speaker product catalog:
http://www.foster-electric.com/products/pdf/microspeakers.pdf
or AAC micro speaker catalog
http://www.aactechnologies.com/category/17, or one can research the product catalogs of any of the other 15 or so ranked micro speaker companies (such as Hosiden, Merry, BSE, Bujeon, Star, Cresyn, Panasonic, etc) which collectively represented over $6.5B in revenue last year (remember this only includes micro speakers not all other speaker applications that AKP technology can address).
In any event if you sift through the catalogs you will notice that there is no real technical or performance advantage between manufacturers. So while you can spend time interpreting the data and footnotes, the bottom line is they all offer pretty much the same spec. Therefore one should feel comfortable in using the specific example below (from Knowles) as representative of a typical micro speaker:
- The sensitivity provided is 73 dB at 1W/m (average over the frequency range).
- The peak power handling is 0.5W and the maximum sinus power is 350mWatts. The max SPL would therefore be well below 73 dB at 1m at the maximum power.
- The plot also confirms these figures and it shows average value of 90 dB. Now if you read the caption below the graph clearly states that it was measured at 0.1m and 350mW - the maximum continuous power of the speaker.
- Therefore the maximum SPL of this speaker at 1m is exactly 20dB below the graph or roughly 70dB on average – which is precisely what they published as the sensitivity parameter of their speaker.
So there we have it. I doubt anyone will think it's worth defending the "insight" Nice One brings to our board anymore. I just sincerely hope that misinformation was an honest mistake.
(20min delay)