Hi MattyE.
The reasons I'm doing a bit of research and still posting about this, a company I own no shares in, and don't intend to at this stage, is as follows:
1. As mentioned before I think the idea is elegant and the technology facinating with great promises of form factor, simplicity (digitally driven transducers) and efficiencies. This piqued my interest initially in the company. Reading some of the available material, I found the technical detail lacking and saw IMO some mutton being dressed up as lamb. I posted a while back maybe 6 months to try and understand it some more, get some answers to my questions etc.
2. I concluded then that I would wait until some more results/evidence cam out about the tech. It was announced the other day, and I was disappointed by the lack of detail.
3. I shared my views about this, as I can see it is very difficult to draw accurate conclusions about the viability of the tech from what is provided. I also am sensitive to people making claims about things without backing the claims up with hard evidence. I am technical in nature and my day job requires this. I am not in the audio industry and I am not an audio specialist, although almost followed a career path in audio engineering.
3. I would have stopped posting many posts ago, but posters have asked me questions, as you have here and I want to respond, as I do this in my day job.
I don't care enough to make the phone calls you are suggesting I make.
To quote your answer to my question:
'So to answer Nice One’s questions:
1.To plot the typical micro speaker curves, AKP would have taken a sensitivity plot for a micro speaker at 10cm and 1 Watt, then subtracted 26dB to get the SPL at 1 meter and 0.5 Watt (the maximal handling power of a typical micro speaker).
2.The AKP comparative line charts would be normalised for an apples to apples comparison to show the actual maximum SPL at 1m.'
For number 1. first of all, sensitivity for micro speakers, as I posted, it seems the industry standard is to measure at 10cm as you have said, but at 0.1 Watts. You have written 1 watt. This was key to my whole point.
I linked micro speakers in that post, measured at 0.1W at 10cm, that had sensitivities ranging from 83 to 89dB approx. These speakers had power handling ratings of up to 1watt. Meaning you could increase power to 1 watt and in theory increase output by 10dB (with audio power, a tenfold increase in power is 10dB) which would result in outputs from the micro speaker of approx 93 to 99dB in theory, in practice a bit less.
You need to subtract 20dB following the inverse square law, to convert to the equivalent of 0.1w at 1 metre. Then to convert to 1 watt at 1 metre, you need to add back 10dB (tenfold power).
So to simplify, to convert from 0.1w/10cm to 1W/1metre equivalent, you subtract 10dB. If you are converting from 1w/metre to 0.1w/10cm you add 10dB.
Looking at the typical micro speaker line in their chart, if you convert back to what the micro speaker industry uses, you have approx 70dB, add 10db and you have approx 80dB, peaking at about 10400hz at 84db.
these figures (when comparing to the linked micro speaker specifications) look very very much like sensitivity results, not maximum spl results. This fellow you have spoken with is indicating that the chart used is supposed to be max power at 0.5 w. That is low but would be the max power of some micro speakers. Even so I think it's still 5 times what is indicated by my study detailed above.
I continue to find this suspect, I'm sorry MattyE. To summarise, IMO, the chart shows max spl for the AP chip and shows approx one tenth of max power for the comparison typical speaker. Check my numbers, look up the inverse square law for distance calculations, and dB/audio power calcs or charts.
You will find I will not post again unless someone asks me another question or some new results or media article, interesting broker report etc is published.
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