I think there is something wrong with your calculations... Either I serve harder than I thought or you serve slower than you thought. Check out my video, compare to some of the faster ones... They "sound" somewhat faster, and I calculated 189km/h.
Hi dude. Well I was about 5mph off of the real speeds because the k850i quality was crappy and i had to calculate time with the sound using audacity and not with the frames count witch is the correct one. Because of camera position and physics (speed of sound) the time a serve sounds on camera isn't the real time of the serve so only fps count is the right method with good video of course! The right speeds for these are 164kmh, 183kmh and 191kmh respectively, and I'm not
intended to call serves like 60mph 100mph u know but to show people my serves and how fast look certain speeds (even if this is a low quality video). (ps now i serve my hard ones over 120mph tested with better form)
I saw your video you got some nice serves there. Your faster seemed to be the 0:40 one whitch you commented. Well I downloaded your video and measured it properly using the speed calculator in my description. The speed is almost similar to the last one in this video.
Don't le the sound fool you and make you think it is much faster than my last one. The firtst 2 sounds (racket contact-ball bounce) sounds pretty much the same for both serves and are the ones that count. The third sound you hear is the racket of your buddy who contacts the ball much closer than mine which hit the back wall which is a far longer distance. So from third sound of the ball many may misundestood the serve as faster.
I'll post my measurement for your serve on your video.. Cheers!
racket hit has to travel a longer distance to the phone to get detected. So the time distance between hit and bounce sounds "closer" and the serves were percieved faster that their actual speeds. the opossite would have happen with phone recording from behind the server.
I estimated that the serves sounded faster about 5% than their actual speeds comparing to other videos and aboout same camera positions, so they were actually in the range:
I know now, that i actually disregarded the speed of sound which is a factor that affects the actual time calculation of the serve at the two crucial spots.
Well, to explain, because the phone was recording from opossite side of the serves, they sounded faster than they what they actually were. This is physics. The distant hit of the racket takes longer to register its sound in the camera while the closer to the camera bounce of the ball less because the sound of the (cont)
This is an old video and actually the first in which i tried to measure the speeds and not to say huge overestimates to people.
I used the calculator in description which i found to be very accurate testing it in roddick's serves for example.
Because of the crappy video quality of the k850i to measure the time (aka frames) i used the sound and not the image off the the ball that makes when it gets hit form racket and when it touches the ground using smplayer for that.
Yuubi the quality is crap but read my explanation if you are not just a hater. The speeds are about 5-7mph slower that what it is shown on the labels but I didn't do it on my knowledge. Moreover, try to measure your serves with camera and the calculator in description and you'll see that a fast serve on court seems quite slower on camera if that's your point.
I serve regularly in mid 120s nowadays and I'm 6', 25 years old male. Is that uncommon for you? :P
I think there is something wrong with your calculations... Either I serve harder than I thought or you serve slower than you thought. Check out my video, compare to some of the faster ones... They "sound" somewhat faster, and I calculated 189km/h.
BrainSane237 5 months ago
@BrainSane237
Hi dude. Well I was about 5mph off of the real speeds because the k850i quality was crappy and i had to calculate time with the sound using audacity and not with the frames count witch is the correct one. Because of camera position and physics (speed of sound) the time a serve sounds on camera isn't the real time of the serve so only fps count is the right method with good video of course! The right speeds for these are 164kmh, 183kmh and 191kmh respectively, and I'm not
spanosa7 5 months ago
intended to call serves like 60mph 100mph u know but to show people my serves and how fast look certain speeds (even if this is a low quality video). (ps now i serve my hard ones over 120mph tested with better form)
I saw your video you got some nice serves there. Your faster seemed to be the 0:40 one whitch you commented. Well I downloaded your video and measured it properly using the speed calculator in my description. The speed is almost similar to the last one in this video.
spanosa7 5 months ago
@spanosa7 Well what was the exact speed of that serve with fps method?
BrainSane237 5 months ago
@spanosa7 Well what was the exact speed of that serve with fps method?
BrainSane237 5 months ago
Don't le the sound fool you and make you think it is much faster than my last one. The firtst 2 sounds (racket contact-ball bounce) sounds pretty much the same for both serves and are the ones that count. The third sound you hear is the racket of your buddy who contacts the ball much closer than mine which hit the back wall which is a far longer distance. So from third sound of the ball many may misundestood the serve as faster.
I'll post my measurement for your serve on your video.. Cheers!
spanosa7 5 months ago
(cont)
racket hit has to travel a longer distance to the phone to get detected. So the time distance between hit and bounce sounds "closer" and the serves were percieved faster that their actual speeds. the opossite would have happen with phone recording from behind the server.
I estimated that the serves sounded faster about 5% than their actual speeds comparing to other videos and aboout same camera positions, so they were actually in the range:
102mph, 114mph, 119mph
Chill out haters!
spanosa7 6 months ago
continued...
I know now, that i actually disregarded the speed of sound which is a factor that affects the actual time calculation of the serve at the two crucial spots.
Well, to explain, because the phone was recording from opossite side of the serves, they sounded faster than they what they actually were. This is physics. The distant hit of the racket takes longer to register its sound in the camera while the closer to the camera bounce of the ball less because the sound of the (cont)
spanosa7 6 months ago
This is an old video and actually the first in which i tried to measure the speeds and not to say huge overestimates to people.
I used the calculator in description which i found to be very accurate testing it in roddick's serves for example.
Because of the crappy video quality of the k850i to measure the time (aka frames) i used the sound and not the image off the the ball that makes when it gets hit form racket and when it touches the ground using smplayer for that.
continued...
spanosa7 6 months ago
Okay ... I serve at ~210 km/h
Yuubi93 8 months ago
@Yuubi93
Yuubi the quality is crap but read my explanation if you are not just a hater. The speeds are about 5-7mph slower that what it is shown on the labels but I didn't do it on my knowledge. Moreover, try to measure your serves with camera and the calculator in description and you'll see that a fast serve on court seems quite slower on camera if that's your point.
I serve regularly in mid 120s nowadays and I'm 6', 25 years old male. Is that uncommon for you? :P
spanosa7 6 months ago
lol
hugopelle 9 months ago
@hugopelle
lol you're the clown of youtube i guess..
spanosa7 6 months ago