• FAQ  • Search  • Memberlist  • Usergroups   • Register   • Profile  • Log in to check your private messages  • Log in 

Cup depth: what's really happening?



 
Post new topic   Reply to topic    trumpetherald.com Forum Index -> Mouthpieces
View previous topic :: View next topic  
Author Message
Proteus
Veteran Member


Joined: 23 Sep 2010
Posts: 130
Location: Ottawa, Canada

PostPosted: Sat May 08, 2021 5:58 am    Post subject: Cup depth: what's really happening? Reply with quote

I understand that changes in cup depth results in changes in the frequencies and amplitudes of overtones in the sound, and that's why changing cup depth changes the sound.

But can anyone tell me what it is specifically about cup depth that actually drives this change? Put another way: we know it does - but why does it?

Thx.
_________________
Bach 239 C
Kanstul 700
Getzen Proteus 907S Bb
Bach Strad 37 Bb (70s)
ACB Doubler flugel
Getzen Capri cornet
Back to top
View user's profile Send private message
JayKosta
Heavyweight Member


Joined: 24 Dec 2018
Posts: 3276
Location: Endwell NY USA

PostPosted: Sat May 08, 2021 6:18 am    Post subject: Reply with quote

I'll make a guess - just to get the conversation started.
Daryll might be able to describe the 'science' involved.

The volume (and shape) of the cup determines how it will respond as a 'shock absorber' to the various vibration/pulsation frequencies and their amplitude.
The pressure inside the cup is always exerting a force back onto the lips, and the cup rim size / shape / volume / etc. has an influence on the precise blend of forces on the lips.
_________________
Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.
Back to top
View user's profile Send private message
Proteus
Veteran Member


Joined: 23 Sep 2010
Posts: 130
Location: Ottawa, Canada

PostPosted: Sat May 08, 2021 6:44 am    Post subject: Reply with quote

Thanks for the quick input, Jay. I can see that "loading the back pressure" (for lack of a better description) from the cup might be a factor...but once it's loaded, it would be in a steady state (continuously loaded) from then on while blowing.
_________________
Bach 239 C
Kanstul 700
Getzen Proteus 907S Bb
Bach Strad 37 Bb (70s)
ACB Doubler flugel
Getzen Capri cornet
Back to top
View user's profile Send private message
Proteus
Veteran Member


Joined: 23 Sep 2010
Posts: 130
Location: Ottawa, Canada

PostPosted: Sat May 08, 2021 6:52 am    Post subject: Reply with quote

The other thing I considered (then quickly discounted) was that the internal volume somehow affected the frequencies (balance of overtones) and thus the resulting tone. But are mid-to-high frequency wavelengths meaningful within the small dimension of a mouthpiece cup?

I wonder: if we took the same horn and played the same notes on a succession of deeper-to-shallower mouthpieces and ran the output through a spectrum analyzer, would it show the lower frequencies remaining pretty much the same but the upper-mid and higher frequencies changing more markedly?

Could this be the correlation between cup depth and tone?
_________________
Bach 239 C
Kanstul 700
Getzen Proteus 907S Bb
Bach Strad 37 Bb (70s)
ACB Doubler flugel
Getzen Capri cornet
Back to top
View user's profile Send private message
JayKosta
Heavyweight Member


Joined: 24 Dec 2018
Posts: 3276
Location: Endwell NY USA

PostPosted: Sat May 08, 2021 6:52 am    Post subject: Reply with quote

My thought is that the 'back pressure' is not a single static 'psi amount' - it contains all the various frequencies and their associated strength (psi at each individual frequency). How all those various back pressureS affect lip movement is what impacts the tone.
_________________
Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.
Back to top
View user's profile Send private message
JayKosta
Heavyweight Member


Joined: 24 Dec 2018
Posts: 3276
Location: Endwell NY USA

PostPosted: Sat May 08, 2021 7:02 am    Post subject: Reply with quote

Proteus wrote:
... But are mid-to-high frequency wavelengths meaningful within the small dimension of a mouthpiece cup? ...

---------------------------------------------
The resonate harmonics of the trumpet's tubing will get 'forced back' into the cup - it isn't a matter of the cup itself having harmonics. The trumpet sort of dictates the composition (frequencies and amplitudes) of the back pressure in the cup.
When just 'buzzing the mouthpiece' there is very little (if any) back pressure resonance - that's why it is possible to do a smooth no-jumps gliss of pitches from low to high on just the mouthpiece.
_________________
Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.
Back to top
View user's profile Send private message
Vin DiBona
Heavyweight Member


Joined: 24 Dec 2003
Posts: 1473
Location: OHare area

PostPosted: Sat May 08, 2021 7:26 am    Post subject: Reply with quote

This can only be truly answered by expert mouthpiece makers.
Maybe a manufacturer who posts here has the time to give you the straight scoop.
Everything effects everything. What if you have a modified C/V cup? What does the throat entrances do? How does the back bore effect the shape and depth of the cup?
Read this.
https://www.everythingtrumpet.com/schilke/Symphony_Series.html
R. Tomasek
Back to top
View user's profile Send private message Send e-mail
Proteus
Veteran Member


Joined: 23 Sep 2010
Posts: 130
Location: Ottawa, Canada

PostPosted: Sat May 08, 2021 8:05 am    Post subject: Reply with quote

Thanks for the Schilke link, RT. As expected, it states that deeper cups give this sound and shallower ones that sound, but doesn't come anywhere near to explaining why. While it also mentions that a cup's bowl-vs-V shape (as well as backbore and throat) are critical to overall resistance, it says nothing about why & how cup depth influence the overtone series. Hmmm...

Jay, I appreciate that each horn's characteristic influences the final sound, but would like to understand more about how a horn's standing waves get "forced back into the cup". I understand the mouthpiece inputs energy into the system (horn) but had not read that there is a feedback loop all the way back into the mouthpiece.

I'm also thinking that we can even hear a difference in the buzz when the same player buzzes into a shallow vs a deeper cup. So given the identical parameters of rim, throat and backbore, I'm pretty sure something is happening well before the horn.
_________________
Bach 239 C
Kanstul 700
Getzen Proteus 907S Bb
Bach Strad 37 Bb (70s)
ACB Doubler flugel
Getzen Capri cornet
Back to top
View user's profile Send private message
Tpt_Guy
Heavyweight Member


Joined: 16 Jul 2004
Posts: 1101
Location: Sacramento, Ca

PostPosted: Sat May 08, 2021 8:10 am    Post subject: Re: Cup depth: what's really happening? Reply with quote

Proteus wrote:
I understand that changes in cup depth results in changes in the frequencies and amplitudes of overtones in the sound, and that's why changing cup depth changes the sound.

But can anyone tell me what it is specifically about cup depth that actually drives this change? Put another way: we know it does - but why does it?

Thx.


Some light reading for you.

https://cderksen.home.xs4all.nl/images/Conns_Blue_Booklet.pdf

The Proper Selection of Cup Mouthpieces by Jody C. Hall. A good little book that has much information about each component of a mouthpiece and its effects.

Here's a bit more reading.

http://newt.phys.unsw.edu.au/jw/brassacoustics.html#mouthpiece
_________________
-Tom Hall-

"A good teacher protects his pupils from his own influence."
-Bruce Lee
Back to top
View user's profile Send private message
JWG
Veteran Member


Joined: 27 Jul 2011
Posts: 255

PostPosted: Sat May 08, 2021 8:14 am    Post subject: Reply with quote

I am not an expert mouthpiece maker, but I suspect that there exists a verily simple principle behind the effect of mouthpiece depth.

The depth of the mouthpiece determines the frequencies that naturally form and propagate from it. Analogize from the micro of the mouthpiece to the macro of something like a pipe organ. The shorter the pipe, the higher the pitch and overtones; the longer the pipe, the lower the pitch and overtones. The reason "why" appears clear, lower pitches and overtones require longer distances to resonate while higher pitches require shorter distances to propagate. This fundamental principle appears true in all families of instruments: winds, strings, percussion, etc.

So, a shallow cup mouthpiece promotes higher overtones to resonate within its short depth while a deeper cup mouthpiece will promote lower overtones to resonate within its longer depth.
_________________
Flip Oakes Wild Thing Bb and C with 1.5 TCC, XT, C, C-O, O, & L mouthpieces
Bach 183S (undersprung valves & straight taper pipe) with 1.5 Flip Oakes XF
Back to top
View user's profile Send private message
Proteus
Veteran Member


Joined: 23 Sep 2010
Posts: 130
Location: Ottawa, Canada

PostPosted: Sat May 08, 2021 8:57 am    Post subject: Reply with quote

Quote:
a shallow cup mouthpiece promotes higher overtones to resonate within its short depth while a deeper cup mouthpiece will promote lower overtones to resonate within its longer depth.


Exactly what I was wondering, hence my question re frequency lengths given the dimensions of a trumpet mouthpiece...and whether - given their wavelengths - the lower frequencies would therefore be pretty much the same for most pieces?
_________________
Bach 239 C
Kanstul 700
Getzen Proteus 907S Bb
Bach Strad 37 Bb (70s)
ACB Doubler flugel
Getzen Capri cornet
Back to top
View user's profile Send private message
JayKosta
Heavyweight Member


Joined: 24 Dec 2018
Posts: 3276
Location: Endwell NY USA

PostPosted: Sat May 08, 2021 9:03 am    Post subject: Reply with quote

Proteus wrote:
...
Jay, I appreciate that each horn's characteristic influences the final sound, but would like to understand more about how a horn's standing waves get "forced back into the cup". I understand the mouthpiece inputs energy into the system (horn) but had not read that there is a feedback loop all the way back into the mouthpiece. ...

--------------------------------
The standing wave(s) in the trumpet tubing have a 'termination point' near the mouthpiece (I don't know the exact location, it might be at the lips, cup, mpc throat, backbore, leadpipe venturi, etc.) where they get reflected back towards the bell.
This 'point of wave reflection' is where the standing waves 'interact' with the pressure waves (pulses) being produced by the player

edit: I didn't mean to imply that there is a single specific point where the reflection occurs. Each individual resonant wave (harmonics included) is likely to have a slightly different location. My main point is that there are termination/reflection points, and they are where the pressure forces from the player interfaces with the internal pressure of the trumpet's standing waves.

My (another) guess is that there is a good corollary in electrical oscillator circuits. Where the overall circuit has its own resonant harmonics (similar to the trumpet tubing).
_________________
Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.


Last edited by JayKosta on Sat May 08, 2021 10:43 am; edited 1 time in total
Back to top
View user's profile Send private message
Proteus
Veteran Member


Joined: 23 Sep 2010
Posts: 130
Location: Ottawa, Canada

PostPosted: Sat May 08, 2021 10:09 am    Post subject: Reply with quote

Riiight...of course there'd have to be a point like that. Thx.

Wonder if Brent or another trumpet maker on the forum could advise on where that point is. Mouthpiece throat (ie. venturi) maybe?
_________________
Bach 239 C
Kanstul 700
Getzen Proteus 907S Bb
Bach Strad 37 Bb (70s)
ACB Doubler flugel
Getzen Capri cornet
Back to top
View user's profile Send private message
Divitt Trumpets
Heavyweight Member


Joined: 11 Aug 2015
Posts: 519
Location: Toronto

PostPosted: Sat May 08, 2021 10:17 am    Post subject: Reply with quote

Each note has a different wave length, and the reflection point changes slightly depending on the harmonic and length of the tube (trumpet plus whatever slides) being used.
_________________
www.divitt-trumpets.com
www.facebook.com/divitt.trumpets
www.instagram.com/divitttrumpets
Back to top
View user's profile Send private message Visit poster's website
Andy Cooper
Heavyweight Member


Joined: 15 Nov 2001
Posts: 1804
Location: Terre Haute, IN USA

PostPosted: Tue May 11, 2021 7:47 am    Post subject: Reply with quote

Here is a starting place for you:

I would start with this book. It was the one college music majors use in an Acoustics-for- musicians -who- don't -know- much- math physics course .

Fundamentals of musical acoustics by Benade, Arthur H
https://archive.org/details/fundamentalsofmu0000bena

Then some articles.
http://stomvi-usa.com/wp-content/uploads/2014/12/1968Trumpet-Intonation-Improvement-with-Multiple-Helmholtz-Resonator.pdf

These two articles to together:
http://pub.dega-akustik.de/DAGA_1999-2008/data/articles/001633.pdf
https://hal.archives-ouvertes.fr/hal-02587854/document

This on has many good citations
https://www.researchgate.net/publication/258248923_Trumpet_mouthpiece_manufacturing_and_tone_quality

Good luck - I know just enough to put the mouthpiece in the little end of the horn.
Back to top
View user's profile Send private message
JayKosta
Heavyweight Member


Joined: 24 Dec 2018
Posts: 3276
Location: Endwell NY USA

PostPosted: Tue May 11, 2021 8:22 am    Post subject: Reply with quote

I've been looking for more details that explain WHY the mouthpiece shape and size affects the produced sound.
What I have mainly found is research and opinion about 'what shapes' result in 'what results', but very little about the HOW (physics and acoustics) of why the changes happen.

The interior volume and tapers of a mouthpiece are quite complex, and there is a lot of change happening in a short distance (rim to end of shank). Most of the physics/acoustic knowledge/theory is based on straight cylindrical tubing, and long even tapers. The interior changes from rim to bell are not an easy fit into the standard formula and principles.

One article mentioned the affect of lip protrusion into the mouthpiece, and how it varies from player to player, pitch, and loudness.
_________________
Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    trumpetherald.com Forum Index -> Mouthpieces All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group