Qts Qes Qms?

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im new to this and i am having a hard time understanding Qts Qms Qes. it seems to be the mecahanical and electrical damping of a speaker. can someone please explain very slowly to me what this means?

i am used to seeing damping used in electrical engineering diagrams on paper, solved using differential equations. im not sure if this is even the same kind of damping. ex: over/under/critical damping

if someone could put some real world words to this it would help me a lot.
 
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i am used to seeing damping used in electrical engineering diagrams on paper, solved using differential equations. im not sure if this is even the same kind of damping. ex: over/under/critical damping

All that really matters for designing sealed speaker enclosures is Qts
Qtc=Qts*sqrt(Vas/Vb+1)
Fc=Fs*Qtc/Qts
Transfer function: H(s)=sn^2/(sn^2+sn/Qtc+1) : sn=normalized frequency
Qtc=0.5 is critically damped....

For anything else, go to wikipedia, or go to The Subwoofer DIY Page - applicable to more than just subwoofers..
 
im new to this and i am having a hard time understanding Qts Qms Qes. it seems to be the mecahanical and electrical damping of a speaker. can someone please explain very slowly to me what this means?

i am used to seeing damping used in electrical engineering diagrams on paper, solved using differential equations. im not sure if this is even the same kind of damping. ex: over/under/critical damping

if someone could put some real world words to this it would help me a lot.

The Qms is a measure of the damping caused by the mechanical damping of the diaphragm suspension. A higher Qms means less mechanical damping.

The Qes is a measure of the electromechanical damping caused by voice coil resistance and the interaction of the voice coil in the magnetic gap. A higher Qes means less electromechanical damping or a smaller magnet.

The Qts is the total damping which is the combination of mechanical and electromechanical damping.

Qms is always much larger than Qes because the electromechanical damping always dominates.
 
thanks for the response but you told me almost nothing. what im looking for is someone who understands this topic enough to be able to explain electrical/mechanical damping in REAL words or possibly an analogy.

No, you want to be spoon fed an answer, but I'm not your caregiver.

Here's your analogy.
mechanical damping = shock absorber
a velocity dependent force dissipating the energy in the suspension and cone mass.

electrical damping = motor back emf try spinning a small DC electric motor with and without the power terminals shorted. also velocity dependent and dissipative, but sourced from the motion of the coil in a magnetic field, acting through the resistance of the coil + wires + amplifier output impedance. Ever heard of Lenz's law?

Good luck.
 
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A good portion of this title can be previewed ( Google Books )...
Loudspeakers: for music recording and reproduction By Philip Newell, Philip Richard Newell, Keith Holland
Chapter 1 : What is a Loudspeaker?
On page 14 ( fig 1.7 ) is an equivalent circuit.

( This might help - Syd )
 
so from what you guys are saying it seems like it is the mechanical and electrical drag or inefficiencies in the speaker? or the speakers "run on" after the music stops

i read the Qts dominates the box volume if this is true why would a speakers inefficiency determine box size?

ive some across lenz's law in school but never more then just touched on it in class. i can see how this would add to the speaker "stopping itself unnecessarily and all of these answers seem to be clearing things up for me, thanks everyone
 
Qts: the higher the number = the drivers inability to come to rest after the electrical signal has ceased. a rating of 0.707 is just right for a lot of folks. If you like drier bass, around 0.5 - 0.6 is better. if you like speakers from the 70's, a little higher 0.8 - 1.0 will make your ears happy.

Do you mean a QTC of .707 or QTS...
 
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so what constitutes a "weak driver" loose/stiff suspension? heavy motor? power rating?

i am working with square kicker L7s and they need to be in a huge box and i am trying to unsderstand why

Thanks to all for their input on this. I am in Mexico and it's hard to find books a) in English b) about these things. Plus ordinary folk on forums sometimes explain things in a way that easier to understand than books...

Scampo77, have you come across any great links/books about all this?
I am especially interested in having an idea of :

- what is a better? Higher or lower ?
- what is a good figure ?
(for basically all the Thiele Small parameters, such as for example here :
Celestion TF0510 5" Professional Speaker 30W 294-2050)

Many thanks guys!
Rick
 
actually you have the right idea with regards with electrical damping analogy of under/critically/over damped; they purposely describe the "ringing" in this physical system. Since an electrodynamic loudspeaker is simply a force driven, damped spring-mass harmonic oscillator, the electrical analogue is very well known and can be found in any college level Physics 101, Electromagnetics, Differential Equations, etc college/university level textbooks.

The same terminology describes the Frequency Response magnitude vs Frequency of a speaker. Lower Qts= more overall damping (not necessarily over-damped because it is all relative), higher Qts= less overall damping. Too high Qts (not enough damping) can result in a peak in the magnitude response within the pass band; too low Qts can result in a very high F(-3) high-pass roll-off, which can hinder bass response. Again, this is all relative as there are an infinite number of loudspeaker alignments to consider.

Qms and Qes are simply the two constituents of the total Quality Factor (Qts). They [Qms and Qes] work together in the "product over sum" rule to establish the total Q(ts).

Engineering is the Best: January 2008

Thiel_small_analysis
 
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The Qms is a measure of the damping caused by the mechanical damping of the diaphragm suspension. A higher Qms means less mechanical damping.

The Qes is a measure of the electromechanical damping caused by voice coil resistance and the interaction of the voice coil in the magnetic gap. A higher Qes means less electromechanical damping or a smaller magnet.

The Qts is the total damping which is the combination of mechanical and electromechanical damping.

Qms is always much larger than Qes because the electromechanical damping always dominates.
I've been on a steep learning curve and am trying to get a better grasp on these and other notions. I think I have a reasonable enough understanding of Qms and Qes (at least for my lay purposes), but I'm still puzzled about something.

If Qts is the sum of Qms and Qes, then why is it that when I look at speaker stats, the Qts is a lower number than both Qms and Qes? There must be something simple that I'm missing here.
 
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