# about driver Q and how its not relevant to anything

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#### MaVo

I wouldnt consider this trolling, so be at ease

I think you had an important insight, namely that an individual TS parameter like qts has not much meaning on its own. Only in combination with other paramters, it can be used to evaluate a driver for a specific purpose.

On one hand, thats a rather obvious thing, as every equation set you use to design a specific enclosure has more than one variable, on the other hand, i also used to look at individual parameters, when i began my speaker building journey. So its a very understandable thing, this realization. It has to come sooner or later, if you use the math.

#### myhrrhleine

You might consider the AES preprint (#1307) by Pat Snider of Speakerlab where he proposes the parameters Fs/Qt and Vas*Qt^2
Back in Nov '77 58th convention

#### nunayafb

I think you had an important insight, namely that an individual TS parameter like qts has not much meaning on its own. Only in combination with other paramters, it can be used to evaluate a driver for a specific purpose.
Important insight... I think not. Mms and BL are just as useless on their own. I am still waiting for you to provide an equation that would allow someone to input Mms and BL and get a box size/tuning.

Qts is not a mathematical construct, it is a total damping factor. I would try and explain it but you seem to have an aversion to learning new things.
Vas and Fs could be explained, but you don't seem to want to accept that the 10's of thousands of people around the world including engineers who design speakers might know what they are doing, because that would imply that your unsubstantiated theory is wrong.

"Q is only the best example of a parameter which people feel like they understand but they really don’t. There is a lot of talk of how “High Q” drivers are good for this and “Low Q” drivers are good for that … all of that is COMPLETE NONSENSE."
Complete nonsense huh, your lack of understanding does not make it nonsense it makes you ignorant.

"As much as EBP is an improvement over Q it still doesn’t tell you something very important – volume of the box you will need. To understand this one must only consider a case of isobaric loading. In an isobaric setup FS and Q (for the combination of two drivers when considered as a single driver) both remain unchanged so EBP remains unchanged but box volume requirement is halved.
What is it that enables an isobaric alignment to work in a smaller volume? It is certainly not Q because Q remained unchanged. The answer is – it is the increased BL."

Hey, way to just arbitrarily leave out Vas which explains the Volume requirement change and just throw in BL.

"I just made up a parameter X for fun and it’s at least a hundred times more useful than Q. In fact parameter X may be the most useful parameter ever and nobody even thought of it. Sometimes I amaze myself."
I think I found the underlying problem here.

"After all a driver is just a motor driving a mass where BL is the motor and MMS is the mass. When the mass begins to interact with the box it enters a resonance which the motor needs to control."

Not to nitpick but there is also the suspension, and the motor has some electrical damping, the suspension provides mechanical damping, together guess what you get...Qts! Low Qts means overdamped-earlier bass rolloff, high Qts means underdamped-hump in the response. The "mass" is attached to a springy suspension, hey wait a mass and a damped spring, that might lead to a resonant frequency (Fs)
Wow we have a resonant system with a specified amount of damping, hmm, all we need to do is determine how it will interact with a volume of air around it. If only there existed a parameter that compared a certain volume of air to the compliance of the drivers suspension, if there was maybe they would call it Vas.

And maybe believers of this "nonsense" would use those three parameters to model woofers and predict their response.

Could you please pick up a book? Loudspeaker design cookbook might help you understand this stuff, if you want to learn that is.

#### vasyachkin

LOL @ nunayafb

i left out suspension on purpose

in fact there is now a second post by Troll in that thread explaining that bit ...

#### vasyachkin

MaVo said:
On one hand, thats a rather obvious thing

not to most people. people like when things mean something. they want Q to mean something ... they want it so bad that often they will not be deterred by silly things like facts.

for example to nunayafb Qts is a "total damping coefficient" and i have no doubt that when many people hear "total damping coefficient" they begin to think of it in terms of those words, not in terms of the actual formulas that define it.

it is not only in politics where words are used to hide the meaning.

#### nunayafb

You are a true BS artist, apparently you are not here for any other reason than to cause trouble so I am done with you.

Funny how everything you said about me is actually a description of you. Everyone knows you are wrong because you keep refusing to provide evidence.

Get over yourself..

#### planet10

Paid Member
Standard T/S parameters are mathematical constructs based real physical speaker parameters with the purpose of making it easier to calculate box alignments (a calculator was a very expensive & expensive appliance in those days, sliderules ruled).

BL is a real parameter, Vas is a construct.

If you want to read a book, read Leo Beranek

dave

#### vasyachkin

planet10 said:
BL is a real parameter, Vas is a construct.

exactly.

#### sreten

vasyachkin said:

Hmmm .....

This thread is as boring and stupid as it gets.

Discussing just exactly how people who do not understand something
actually misunderstand it is pointless, as is the title of this thread.
How you think that "how stupid you think people are" is an interesting
topic is quite beyond me.

As for driver Q not being relevant - idiotic.

/sreten.

#### planet10

Paid Member
sreten said:
As for driver Q not being relevant - idiotic.

It is very relevant... and given that it has been used long enuff that it directly relates to how we look at real-world results has become more useful than the physical properties it is a construct of. Small's work was brilliant and has made repeatable bass alignments to the masses...

Some of the discussion above is a bit disingenuous thou.

dave

#### MaVo

well, the tone of his posts is something different for sure, but i think we can see through that and keep cool. i mean, every one of us was 15 years old at some day in the past, so we ought to understand

#### Andy G

MaVo said:
well, the tone of his posts is something different for sure, but i think we can see through that and keep cool. i mean, every one of us was 15 years old at some day in the past, so we ought to understand

And you are just seeing the tip of the iceberg !!!

#### KSTR

If one understands filter theory, the driver Q is very meaningfull. That's why this parameter was labeled "Q", after all: the Q of the corresponding highpass filter function...

- Klaus

#### Variac

Paid Member
Well, tone is often what gets people into the bin for a week...

#### nunayafb

Apologies for the tone all. Maybe some of you have not had the pleasure of reading his other posts where he says he can determine box requirement by "holding a speaker in his hand" and other wild illogical statements.
I have tried repeatedly to get him to justify his assertions and he refuses. Is it so much to ask for an equation using BL and Mms that can be used to model enclosures?

Mathematical construct or not? who cares, I don't. T/S parameters, regardless of how you categorize them, are used to model enclosures, period.
BL and Mms are not, if someone uses them for some purpose other than discussing weight and motor strength I would love to hear about it. Seriously.

#### vasyachkin

sreten said:
Discussing just exactly how people who do not understand something
actually misunderstand it is pointless, as is the title of this thread.
How you think that "how stupid you think people are" is an interesting
topic is quite beyond me.

studying stupidity of other people is the most important thing.

figuring out the right answer is kindergarten stuff - its too easy. the interesting question is - which wrong answer will the masses accept as the right one ?

what do you think politics is about ? about fixing problems ? LOL !

stupidity is what politics and high-end audio are all about.

being right gets you nowhere. people who succeed in business and politics are the ones who correctly predict other people's mistakes.

#### vasyachkin

nunayafb said:
T/S parameters, regardless of how you categorize them, are used to model enclosures, period.
BL and Mms are not

Bl and Mms are not TS parameters ? if you say so.

any formulas for modeling boxes based on only BL, Mms and SD would be approximate. what i am describing is not intended for modeling but for rough estimation when deciding which drivers should be modeled and which are obviously junk.

yes you should be able to hold the driver in your hand and realize that its not worth modeling because its garbage. for two similar drivers though you would need to model both of them to find out which one is best.

#### planet10

Paid Member
nunayafb said:
where he says he can determine box requirement by "holding a speaker in his hand"

Depends on how accurate you define requirements. The above is not all that hard. I've been doing it for years.

Is it so much to ask for an equation using BL and Mms that can be used to model enclosures?

The Beranek referenced earlier derives box parameters using real physical driver characteristics such as those 2. Wilmslow Burhoe used these for all his boxes (EPI, Genesis)

dave

#### MaVo

vasyachkin said:
studying stupidity of other people is the most important thing.

Variac, you are right, i feel like a fool to have defended him. now im off into more productive areas of this board

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