Alternative a2dp driver Bluetooth SBC and LDAC measurement testing and comparison
My main setup htpc lost its power supply last week. Waiting for repair I couldn’t stay without quality music. I thus use my old surface pro 2017 together with this superb Alternative A2DP Driver to drive my system. Thanks to
@gerG to have introduce it.
I wanted to use the portable computer because I could then keep the benefit of convolution room correction which is not possible as far as I know with an android phone.
Although it is a well-known fact that LDAC is good. I have tested the driver with the surface pro and SMSL-D6s. With a Bluetooth chip that is quite old I couldn’t get stability with better than LDAC SQ medium quality ie 660kB/s. HQ would need 990kBit/s, I cannot achieve it.
First let’s check from where we are starting from
Test with standard SBC windows drivers for comparison basis.
Surface standard driver Bluetooth to SMSL-D6s to E1da cosmos stereo mode-green led. The E1DA cosmos is good enough to make valid measurements.
Standard SBC THD+N at 1000Hz is -66dB, the distortion is drown into noise. Bad results where expected of course.
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Multitone result is not brilliant: 8 to 10 bit only definition
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Surface with Alternative A2DP driver with sbc is 3 to 4dB better but nothing significative. I also tried to increase the SBC bitpool up to 110 almost doubling the SBC speed to 642 kBit/s, it did give better results but not yet good enough
Multitone SBC Bitpool 110 apparently more than 20dB to 30 dB better than standard SBC .
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Surface with Bluetooth Alternative A2DP driver with LDAC SQ Medium Quality settings.
I couldn’t test the High Quality settings that would give a speed of 960 kbit/s, but the Medium Quality already provides quite good results.
Test with 1000Hz signal, THD+N of -116dB . It is 50dB better than the standard drivers and looks almost as good as the USB input!
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Bandwidth start to decline a bit early at 15kHz. Some people may not like it, I don’t mind as it is perfect until there.
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Test THD+N function of frequency. The results are excellent. One can notice that THD is always neglectable compared to noise. THD+N curve is almost the same as the N curve.
Blue THD+N; Green Noise ; White distortion
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Test with 19 and 20 khz signal
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Surface LDAC IMD din test excellent -110db
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And now Multitone the most difficult test .It gives 18 bits until 10-12kHz . Results are not as good above 13kHz but I believe that this higher distortion is not audible.
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The above multitone test has been done with SMSL D6s below is the multitone test with the Topping E70. It shows very similar results thus the tests are not DAC dependent and that probably the shape of multitone at higher frequency is a LDAC thing.
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As a conclusion results are very satisfactory with PC and LDAC even with SQ medium quality 660kBit/s, I do not need LDAC HQ 990 kB/s. I am very happy with this Alternative A2DP driver . I can now use my laptop and Bluetooth and getting excellent sound quality.