explain to a dummy

[Thebrain]

hello everyone.
i searched the forum for a simple explanations about speakers parameters.
couldn't find one(unless it's buried in a prehistoric thread )....
i understand some of them but in every speaker specifications
i meet those 3 or 2 letters combos (Qms,Vas,Le etc...)followed by a value that makes me feel like i don't understand anything

can someone please shed some light about these parameters?
and please make the explanation idiot proof cause this stuff is
really new to me

here is an example of these parameters that make you feel
like you should ask a pro:

Nominal Impedance 6 ohm
DC Resistance (Re) 4.2 ohm
Voice Coil Inductance (Le) 1.2 mH
Effective Piston Area (Sd) 508 cm2
Voice Coil Diameter 75.55 mm
Voice Coil Height 28 mm
Air Gap Height 6 mm
Linear Coil Travel (p-p) 22 mm
Maximum excursion (p-p) 0.87 T
Magnet Weight 2.03 kg
Net Weight 5.85 kg
Free Air Resonance 19 Hz
Sensitivity (2.83V/1m) 91 dB
Mechanical Q-factor (Qms) 7.8
Electrical Q-factor (Qes) 0.42
Total Q-factor (Qts) 0.40
Moving Mass incl. air (Md) 98 g
Force Factor (BL) 10.8 Tm
Equivalent Volume (Vas) 238 l
Compliance (Cms) 650 um/N
Mechanical Loss (Rm) 1.5 kg/s
Rated Power Handling 200 Watt

 

[Mooly]

I think what you are looking for is an explanation of Thiel-Small parameters,
http://en.wikipedia.org/wiki/Thiele/Small

It's a hugely complicated subject

 

[901Fixer]

I consider myself somewhat new to all of this even though I've been building and buying audio for many years. I hope there is a link to a good explanation of the various terms or at least a list of all of the acronyms. If you can get one of the various simulation programs for building enclosures I think that would help explain how different values effect things and how control the design parameters.

I'm no genius but usually pick up on new concepts rather quickly, not so much with Hi-Fi though. It has taken awhile to read thru and digest and ponder on to sorta get a grasp on what gets discussed here. After you get a grasp on all of the factual hard numbers data then you have to factor in personal preferrence and design compromise etc. This part can get heated.

Enjoy yourself and take the time to absorb all of the information on this wonderful site.

 

[Dansk]

Thiele/Small/Elliott...

Alternatively, this could be a possibility. Very short and precise definitions, but also some further explanation:
sound.westhost.com/tsp.htm

 

[Thebrain]

I think what you are looking for is an explanation of Thiel-Small parameters,
http://en.wikipedia.org/wiki/Thiele/Small

It's a hugely complicated subject

thanks. but this is surely not a dummy explanation
i was looking for a more simplified explanation.

901Fixer
i tried to play a bit with bassbox pro and winISD
but i couldn't make much of it.

if what you guys are trying to tell me is that there is no simple explanation
bring in the scuba gear im going in!

 

[901Fixer]

Scuba gear required. I'm sure there is a general way to explain the basics but I haven't found it laid out that way anywhere and I have yet to experiment with any of the design programs but hope to eventually.

 

[infinia]

I think the simplest way of explaining the Theile-Small parameters (T-S,TSP) is that they provide an electrical model to a speaker drivers mechanical properties. This electrical model basically helps understanding the low frequency resonance effect of a drivers properties interaction in a closed box or a tuned resonator box (bass reflex).
The first place to start is to fully grasp the idea of resonance learned in basic physics. Also basic electric circuits, same physics course? Then look at the Small's AES papers which can be found on the net. He has a glossary of the terms as an appendix.

 

[Thebrain]

Alternatively, this could be a possibility. Very short and precise definitions, but also some further explanation: sound.westhost.com/tsp.htm

thanks! this one looks much more informative and
straight forward then the wiki page.

basic physics

you actually mean: my worst nightmare
but i guess there is no running away.
i'm starting to get the picture...
no simple explanation.

 

[MaVo]

One doesnt really have to know the theory behind those parameters to use them. And using them is easy, since you usually just put them into a program and see what comes out

 

[badman]

thanks! this one looks much more informative and
straight forward then the wiki page.



you actually mean: my worst nightmare
but i guess there is no running away.
i'm starting to get the picture...
no simple explanation.

Perhaps, in that case, your nickname is ill-deserved?

 

[Thebrain]

Perhaps, in that case, your nickname is ill-deserved?

indeed

 

[infinia]

One doesnt really have to know the theory behind those parameters to use them. And using them is easy, since you usually just put them into a program and see what comes out

I don't agree. Like any modeling software one should understand or at least have an basic idea what the sofware is doing. In otherwords check the results/limits or else garbage in +software = garbage out .

 

[Thebrain]

I don't agree. Like any modeling software one should understand or at least have an basic idea what the sofware is doing. In otherwords check the results/limits or else garbage in +software = garbage out .

that's right!
i'm sure you can get some results with just putting parameters .
but the only way you can get good results that will actually preform
well in the real world is by understanding the parameters.
that goes probably for everything in life

 

[alspe]

Can someone explain how much Fs parameter restricts bass (performance and) depth? I'm considering some MMTMM project whose midbasses has Fs high as 68 Hz. Is that limiting factor? If I tune BR for example to 52 Hz and my room is quite small and easily boosts 40 Hz frequencies, is Fs parameter limiting factor?

 

[Inductor]

Can someone explain how much Fs parameter restricts bass (performance and) depth? I'm considering some MMTMM project whose midbasses has Fs high as 68 Hz. Is that limiting factor? If I tune BR for example to 52 Hz and my room is quite small and easily boosts 40 Hz frequencies, is Fs parameter limiting factor?

It is a limiting factor. One idea, that I used as a mod to the original design (was to close the vent w/ a sock, at least until the woofer is used a lot), and to make it a closed box to take advantage of the lower extension.