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Expressing relative blade speed |
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slevin
Premier Member Joined: 03/15/2012 Location: USA Status: Offline Points: 3602 |
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Posted: 06/29/2017 at 5:07pm |
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There is a simple way for us to compare relative blade speed of different forum members' blades. It is based on the correlation between frequency and blade speed.
So far, I see a direct correlation between blade speed and frequency. Examples: Garaydia ALC: 1744 Hz Tibhar Drinkhall Powerspin Carbon: 1571 Hz Viscaria: 1507 Hz Innerforce ALC.S: 1270 Hz (a notch slower) The advantage of this method (over the plain old 'hit the blade face on the forehead' method) is that one forum member can compare blade speed with the others in a more definitive way. So, for example, if I'm interested in knowing whether the Apolonia ZLC (owned by a German member) is faster than my IF-Layer ZLC, I just compare my reading vs his. Any obvious contradictions? I shall try use this in blade reviews from now on. I'm interested in seeing other forum members' findings on this. Earlier I used to use a slightly lengthier process via the PC, but a post on TTD directed me to a family of apps that one could use for this.
Edited by slevin - 06/29/2017 at 5:09pm |
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h0n1g
Silver Member Joined: 05/03/2005 Location: CA Status: Offline Points: 839 |
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Great idea. I will add a couple of measurements tonight:
- Timo Boll ALC - Apolonia ZLC - Mizuno Fortius LT Light - Xiom Vega Pro - Xiom Vega Tour - Nexy Zealot - Nexy Lissom - Nexy KJH
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shinshiro
Super Member Joined: 09/21/2016 Location: Brazil Status: Offline Points: 243 |
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How height do you throw/bounce the boll? (I don't know if it makes a difference, haven't downloaded tha app yet)
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BigFatLoop
Member Joined: 05/06/2017 Location: Milky Way Status: Offline Points: 82 |
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Would this frequency measurement take into account all the other blade parameters that might influence blade speed (types of wood, # wood layers, types of carbon, # carbon layers, blade thickness, epoxy used, layer stack-up, layer spacing, etc, etc)? Or would the measurement mostly depend on the hardness and thickness of the outer layer?
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Kolev
Gold Member Joined: 10/04/2004 Location: Belgium Status: Offline Points: 1529 |
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Measuring the frequency may be helpful only if we are having blades from the same brand and model, E.g. BTY TBoll ALC.
The higher the frequency, the more the density of the wood |
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Hallmark Carbon Extreme (x3)
FH: D05/G1/RX BH: Z2/D64/Ω7Pro |
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icontek
Premier Member This is FPS Doug Joined: 10/31/2006 Location: Maine, US Status: Offline Points: 5222 |
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does the frequency vary much towards the tip, away from the sweetspot?
if so, how much?
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yogi_bear
Forum Moderator Joined: 11/25/2004 Location: Philippines Status: Offline Points: 7219 |
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nice
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Independent online TT Product reviewer of XIOM, STIGA, JOOLA, SANWEI, GEWO, AIR, ITC, APEX, YASAKA and ABROS
ITTF Level 1 Coaching Course Conductor, ITTF Level 1 Coach |
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zeio
Premier Member Joined: 03/25/2010 Status: Offline Points: 10833 |
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Measuring the frequency has been proven to work across blades of different compositions. There is a loose correlation between frequency and coefficient of restitution, the latter of which is the real measurement of blade speed. By comparing the frequencies, one can get a good idea of the speed of different blades. The first few modes of vibration is of the most interest. The first mode of vibration, in particular, is low enough to feel through the palm. That said, the built-in mic on most smartphones is not good enough to detect low frequencies. |
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Viscaria FL - 91g
+ Neo H3 2.15 Blk - 44.5g(55.3g uncut bare) + Hexer HD 2.1 Red - 49.3g(68.5g 〃 〃) = 184.8g |
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yogi_bear
Forum Moderator Joined: 11/25/2004 Location: Philippines Status: Offline Points: 7219 |
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i think we just need to have a uniform height of bounce like 6 inches?
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Independent online TT Product reviewer of XIOM, STIGA, JOOLA, SANWEI, GEWO, AIR, ITC, APEX, YASAKA and ABROS
ITTF Level 1 Coaching Course Conductor, ITTF Level 1 Coach |
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iamj8
Super Member Joined: 09/11/2009 Location: NZ Status: Offline Points: 429 |
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Very nice. Once a good amount of data is assembled, the main post should be updated and post stickies. I'm sure it'll help a lot of EJs and players out there.
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A version of Hurricane 3
A version of Tenergy A Stiga blade... |
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Baal
Forum Moderator Joined: 01/21/2010 Location: unknown Status: Offline Points: 14336 |
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Height of the ball shouldn't matter. The blade will resonate at its preferred frequencies. It will just be louder if you drop from greater height. Like plucking a string on a guitar, you can pluck it harder and mostly it will just be louder but the pitch and timbre is the same.
I think it is a really good idea. |
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zeio
Premier Member Joined: 03/25/2010 Status: Offline Points: 10833 |
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Yes, amplitude will change as the drop height and the tightness of grip goes up and down, but the overall waveform will stay the same as the blade will vibrate at its natural frequencies. The location of impact will have a larger influence as that will have an effect on the modes excited. If the ball hits the node of a certain mode, that mode will not be excited.
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Viscaria FL - 91g
+ Neo H3 2.15 Blk - 44.5g(55.3g uncut bare) + Hexer HD 2.1 Red - 49.3g(68.5g 〃 〃) = 184.8g |
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JacekGM
Platinum Member Joined: 02/17/2013 Location: USA Status: Offline Points: 2356 |
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Let us just remember to use the same ball for these comparisons... it takes two to tango.
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(1) Juic SBA (Fl, 85 g) with Bluefire JP3 (red max) on FH and 0.6 mm DR N Desperado on BH; (2) Yinhe T7 (Fl, 87 g) with Bluefire M3 (red 2.0) on FH and 0.6 mm 755 on BH.
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h0n1g
Silver Member Joined: 05/03/2005 Location: CA Status: Offline Points: 839 |
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Yes, ball will make an impact on frequency
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h0n1g
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Nittaku P40+ Ball, dropped from approximately 6 inches, three times in a row. Mizuno Fortius LT Light : 1378 hz Xiom Vega Pro : 1399 hz Nexy KJH : 1291 hz
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h0n1g
Silver Member Joined: 05/03/2005 Location: CA Status: Offline Points: 839 |
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Here's a google submission form if you want to contribute: https://goo.gl/forms/HGki3A0DqfYSXT2A3
Here's the resulting table: Blade Speed Comparison I will get it sorted in a bit
Edited by h0n1g - 06/29/2017 at 11:35pm |
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slevin
Premier Member Joined: 03/15/2012 Location: USA Status: Offline Points: 3602 |
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Great idea! Nice to have a database / table. I shall try upload a few values tomorrow.
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h0n1g
Silver Member Joined: 05/03/2005 Location: CA Status: Offline Points: 839 |
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First slightly questionable result: Xiom Vega Tour: 1299 vs. Xiom Vega Pro : 1399
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qpskfec
Silver Member Joined: 07/28/2011 Status: Offline Points: 517 |
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I would like to see results from testing both sides of a combo blade.
A combo blade being one with an asymmetric design - different composition on each side, typically made for people to use inverted rubber on one side and LP on the other. If one side is much softer wood than the other, are the frequencies the same? |
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zeio
Premier Member Joined: 03/25/2010 Status: Offline Points: 10833 |
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Sounds about right. Xiom official site states that the Pro is faster than Tour. Vega Tour Vega Pro |
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Viscaria FL - 91g
+ Neo H3 2.15 Blk - 44.5g(55.3g uncut bare) + Hexer HD 2.1 Red - 49.3g(68.5g 〃 〃) = 184.8g |
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zeio
Premier Member Joined: 03/25/2010 Status: Offline Points: 10833 |
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Frequencies should be the same, but the amplitude could be different on either side. |
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Viscaria FL - 91g
+ Neo H3 2.15 Blk - 44.5g(55.3g uncut bare) + Hexer HD 2.1 Red - 49.3g(68.5g 〃 〃) = 184.8g |
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haggisv
Forum Moderator Dark Knight Joined: 06/28/2005 Location: Australia Status: Offline Points: 5110 |
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Interesting idea... I can't see it working for all blades though. For example balsa blades can be very slow on low impact, yet very fast at higher impact.
It might work for the more standard blades though. Where is the iphone app?
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SmileTT
Super Member Joined: 04/15/2017 Location: Maryland Status: Offline Points: 240 |
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This is amazing, I look forward to see more numbers!!
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Xiom Omega IV Euro | Freitas ALC | Xiom Omega IV Euro
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qpskfec
Silver Member Joined: 07/28/2011 Status: Offline Points: 517 |
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A combo blade is made so that the ball reacts differently depending on which side you use. The frequency is the same for both sides but the ball reacts differently for both sides. This tells me that knowing the frequency doesn't tell me which side is faster and may or may not be a very interesting fact to know. Coefficient of restitution is much more interesting than frequency. That is why golf club designers measure COR to get the COR up to the legal limit. My guess in tt blades is that COR will vary depending on swing speed due to multiple layers of different materials. Golf club designers measure frequency and tune the frequency. They do not try to maximize frequency for performance, it is done to make the golf club more pleasing to the ear. |
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zeio
Premier Member Joined: 03/25/2010 Status: Offline Points: 10833 |
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Yes, that's exactly the reason I wrote "a loose correlation between frequency and coefficient of restitution" earlier.
Not just blades, but also pretty much everything will produce different CORs for different impact velocities. Bryce Speed Bryce Sriver Y-axis, velocities after impact X-axis, velocities before impact - 7.5 m/s, 15 m/s, 22.5 m/s Edited by zeio - 06/30/2017 at 1:09am |
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Viscaria FL - 91g
+ Neo H3 2.15 Blk - 44.5g(55.3g uncut bare) + Hexer HD 2.1 Red - 49.3g(68.5g 〃 〃) = 184.8g |
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h0n1g
Silver Member Joined: 05/03/2005 Location: CA Status: Offline Points: 839 |
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https://itunes.apple.com/us/app/spectrum-analyzer-real-time-sound-frequency-analyzer/id490078884?mt=8 that should do the same
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vvk1
Gold Member Joined: 11/14/2009 Location: UK Status: Offline Points: 1925 |
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Adidas Hypertouch: 1.6 Khz
Nexy Chedech: 1.4 Khz
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slevin
Premier Member Joined: 03/15/2012 Location: USA Status: Offline Points: 3602 |
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I suggest putting down your blade weight (if you know it). A 80g Viscaria shall show different readings than a 92g Viscaria. Butterfly Marcos Freitas ALC (87g): 1464
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Hozuki
Super Member Joined: 01/22/2017 Location: Germany Status: Offline Points: 477 |
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Hm, this will be inconsistent since blade have frequency peaks of similar amplitude at various frequencies, not just one. Some ppl will surely confuse the pitch by an octave (which is simply half or double the freq).
I would find it more helpful if the actual scale a blade rings in was to be provided. However, that's neither a push-one-button method nor a task manageable by people without some knowledge about music theory. For example, my Stiga OC (85g) has a scale of F#-Dur (detuned) and the first pronounced note is A#. If you only measure a single frequency, then you get either A#, C#, or F#. If I had to decide on one, I would say it sounds most like its prime - F#. That's 1400 Hz. Now you can add it to the list and get on with your life :P |
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arg0
Platinum Member Joined: 07/22/2009 Location: Germany Status: Offline Points: 2023 |
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For a related discussion, see this thread.
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