Still trying to figure out if the Bluetooth latency is due to old version of IOS (10.3.3) running on my iPhone SE.
Since it has no issue on mac book air with latest os version, I'm not too concerned. I did reach out to Anker support and they offered to help (great customer service).
Did some more testing, looks like its a codec issue.
Any video that I shot with my iphone has no latency (thus no audio/video sync issue). Issue is worst with ios youtube app (almost 0.5 sec delay in audio). With youtube loaded on ios safari or chrome the issue is much reduced (~0.1-0.2 sec delay in audio).
I'm not an expert in audio codec area so please do chime in.
UPDATE: Bluetooth Latency
I'm experiencing really bad bluetooth latency with these earphones (when connected to iPhone SE running IOS 10.3.3). It is almost 0.5 sec.
I'm not happy with the latency because it makes watching youtube on my phone almost unbearable. The strange thing is that I do not see this latency with Macbook Air running 10.13.5. Will contact Anker about it.
There are plenty of Soundcore Spirit Pro reviews already posted so I'll keep it short and to the point.
Exterior: It comes in attractive blue/white box.
Contents: Inside the box are following items
Earphones, extra ear tips, extra earwing tips, shirt clip, cable clip, carry pouch, warranty card, user manual and happy/not happy card.
Input - 5V, 0.5A
Charging Time - 1.5 hours
Play Time - 10 hours
Weight - 17g, 0.6Oz
Impedance - 16 Ohms
Driver - 6mm x 2
Frequency Response - 20 Hz - 20 KHz
Bluetooth Ver - V4.2
Range - 10m/33ft
Earphone wire length - 24 inch
microusb charging port is not covered. Anker is confident of waterproofing even without cover.
Sound, fit and feel:
Out of box sound quality is amazing. It is slightly bass rich. Mid and treble are great. Overall listening experience is very enjoyable.
It is very light weight and fits great. I really like the wing tips. It helps to keep the earphones in place while doing various activities.
It is to be noted that these tips are in-ear canal type and provides very good isolation.
These earphones have dual equalizer (can be activated by pressing play and volume up button together for a sec).
In the second equalizer mode sound becomes more bass rich. In my opinion the second mode is not very useful since default sound mode is already bass rich. But this is very subjective as per music and user preferences. It's good to know that bass boost mode is there if needed.
These earphones have magnetic head (where soundcore label is printed) and this is extremely useful feature as you can stick the two pieces like a necklace when earphones are not in use.
I found the included carry pouch to be on the smaller side. It is useful to store the extra ear tips, ear wingtips, etc but is too small to store earphones comfortably (puts too much fold on the wire).
Earphones are exactly 24 inch long. This is a perfect length (well done Anker).
These are great for active users (for running, gym, swimming, etc). I found these extremely useful at my work. I can discreetly listen to music/radio and can hang it when not in use. I also use these as bluetooth handsfree while driving (keeping only one side in ear). These are my everyday earphones. 10 hour battery life is also great to have.
Some pictures of the earphones are below.