Knowledge
We have explained the following topics for you here:
– How does spivo® work in general?
– When do I play spivo® ONE or TWO?
– What does my contact point and grip have to do with the whistle?
– What happens when I put spivo® in the bottom of the racket?
How does spivo® work?
The physics behind spivo® (Part 1)
Have you ever blown into a bottle and made a sound? This is the basic principle of spivo®. Like the bottle, the generated whistling sound depends on the speed of the air flowing through. That is why there are different tones with different speeds of swing.
There are two speed ranges where you can hear a sound produced by the Helmholz resonator (spivo®). A gentle sound produced by slow air flow and a clear sound through fast air flow over the hollow part of the spivo®.
This physical principle ...
Helped us create the spivo®. Thanks to numerous tests we have succeeded in covering all of the spin ranges with only two devices (spivo® ONE & TWO).
The video below explains this.
When do I play spivo® ONE or TWO?
At which speed,
do I play which topspin intensity?
Slide the spin control and hear the matching whistling sound.
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| spivo ONE | No sound | spivo TWO |
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| --- | --- | --- |
 Spin:
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 Power:
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Baseline, midcourt or mini tennis?
ONE
Soft sound
For mini tennis with short children’s rackets and little speed – well suited.
Loud whistling sound
For baseline tennis with high to very high speed – optimally suited.
Soft sound
For T-field to baseline with acquisition or medium speed – well suited.
Loud whistling sound
For baseline tennis with focus on aggressive topspin and maximum stroke speed – ideally suited.
TWO
What does your contact point have to do with the whistle of spivo®?
Your contact point ...
will determine your grip. What does that mean? It means that each grip sets your racket almost parallel to the net, while having a comfortable wrist position at the point of impact. Result: the ball can fly over the net. For example, if you hit the ball late, in other words next to you instead of in front of you, you can only play a “continental (“middle”) grip”.
What does this mean for your topspin or whistle?
Topspin is best performed at a contact point, that is at shoulder height, far in front of the body. At a later, lateral contact point, the strong upward movement of the racket, would cause you to injure yourself with the racket, while hitting the ball. This is why, almost no topspin is generated here. This means that spivo® cannot whistle before the point of contact.
Can you place spivo®
at the bottom of the racket?
The physics behind spivo® (Part 2)
Imagine a Carousel. You sit on the outside and I sit on the inside, close to the center. Which one of us is faster? Sure, you. If I sit close to the center of rotation, I’m much slower.
The time it takes you and I to complete one turn is identical. However, you’ll be travelling a longer distance. So you’re traveling at a higher speed. Hence the air will flow faster over your face than mine.
Carousel and spivo®?
Now you are the spivo® at the top of the racket and I am the spivo® close to the heart of the racket. What happens? The air also flows more slowly over the hole at the bottom. This changes the response behaviour as we know it.
At the bottom of the racket? - then everything shifts up by about 1000 RPM.
What's in it for me?
The result is a reduction in volume, despite reliable feedback on the correct racket position. Try it out.
Now the tones have shifted. Everything shifts up by about 1000 RPM. So now you have to accelerate more until you hear any sound at all.
This has the advantage that the whistles become so quiet that nobody but you can hear it when you play. To make this possible was a real challenge, especially in the production of the filigree sound edge.
Our recommendation.
It is easier to do it than to explain it. So just get on with it! Every player has his own idea of how much topspin he wants to play with. We have only made one suggestion out of many to help you find your way around. In general the recommendation number #1 is still here:
Try it and see.
If you are still stuck, check out our YouTube channel or send us an e-mail to support@spivo.de.
