Ann: Performance Specifications, page-103

MattyE posted:

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."

I was curious to check out the Knowles 2403 260 00001 micro speaker as linked in the above. I used photoshop to take the response curve 'measured in IEC baffle at 350mW with 1ccm back cavity at 10 cm distance' from the datasheet http://www.knowles.com/eng/content/download/3213/38271/version/4/file/2403 260 00001 Donau.pdf on the product, then projected over the AKP chart in the recent announcement, matching the SPL and f[Hz] axis exactly. I then lowered the line by exactly 20dB as per: '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.'

This is what resulted:​

You can open the two documents side by side to verify my work.

What this shows me is the Knowles microspeaker is outperforming the 'Typical mobile phone micro speaker' line by 5dB. This either means the Knowles 2403 260 00001 is not typical and outperforms the typical speaker by 5dB, or AKP have chosen a not so typical curve to compare their one with.

The Ap speaker is still shown to outperform the knowles speaker between 150Hz (10dB) decreasing to even at 550Hz.