needed speaker specifications explained

[Joeteck]

When shopping for speakers for car or home for building, speakers have many specs I don't understand. Maybe many of you can shed some light on this for me, and hopefully others. there are a few I understand, but other I don't. But please explain all of them even if they seem obvious..

Power handling: 70 watts
VCdia: 1-1/4"
Le: 0.53mH
Impedance: 4 ohms
Re: 2.9 ohms
Freq response: 40-20,000 hz
Fs: 48Hz
SPL: 88dB 1W/1m
Vas: 0.60 cu ft
Qms: 2.50
QES: 0.50
QTS: 0.42
XMAX: 3.5 mm
Tweeter crossover: 10Khz @ 6db/octave
Dimensions A: 6-1/2", B: 5-3/4", C: 3-1/4"

 

[R-Carpenter]

I suggest reading Speaker Building 201 by Ray Alden.
The parameters you are asking about, are called T/S for Thiele/Small and describe electromechanical parameters of the driver. Based on this data, some of the behavior can be predicted and calculated. You can for example predict if the driver will work better in a sealed enclosure or ported one.
The more you learn, more you will understand from the data, but there's no straight relationship between the numbers and betterness of the speaker.


http://en.wikipedia.org/wiki/Thiele/Small

 

[Joeteck]

I was hoping for a reply that they could just say what each means, and then I could READ that and learn from that... Answers from you gurus are usually easier to understand than a book...

 

[R-Carpenter]

Power handling: 70 watts Obvious ehh?
VCdia: 1-1/4" Voice Coil Diameter
Le: 0.53mH Voice coil inductance
Impedance: 4 ohms Averaged impedance of the driver
Re: 2.9 ohms DC resistance of the driver
Freq response: 40-20,000 hz .......
Fs: 48Hz Driver resonance
SPL: 88dB 1W/1m .......
Vas: 0.60 cu ft Equivalent air volume of moving mass suspension
Qms: 2.50 Mechanical Q
QES: 0.50 Electrical Q
QTS: 0.42 Total Q
XMAX: 3.5 mm Maximum movement of the cone
Tweeter crossover: 10Khz @ 6db/octave
Dimensions A: 6-1/2", B: 5-3/4", C: 3-1/4"

 

[Joeteck]

Power handling: 70 watts Obvious ehh?
VCdia: 1-1/4" Voice Coil Diameter
Le: 0.53mH Voice coil inductance
Impedance: 4 ohms Averaged impedance of the driver
Re: 2.9 ohms DC resistance of the driver
Freq response: 40-20,000 hz .......
Fs: 48Hz Driver resonance
SPL: 88dB 1W/1m .......
Vas: 0.60 cu ft Equivalent air volume of moving mass suspension
Qms: 2.50 Mechanical Q
QES: 0.50 Electrical Q
QTS: 0.42 Total Q
XMAX: 3.5 mm Maximum movement of the cone
Tweeter crossover: 10Khz @ 6db/octave
Dimensions A: 6-1/2", B: 5-3/4", C: 3-1/4"

Very cool!!!!!!!!!!!!!!!!!

Ok, the demensions A,B and C. What are these measurements?

 

[R-Carpenter]

Different in car audio and speaker making as far as I know.
A should be the cutout size for the basket.
B is the cutout for the lower portion of the basket so the driver drops in the hole and C is the depth of the driver as far as I remember.

 

[Joeteck]

Different in car audio and speaker making as far as I know.
A should be the cutout size for the basket.
B is the cutout for the lower portion of the basket so the driver drops in the hole and C is the depth of the driver as far as I remember.

DUDE! Ok, all the Q stuff... anything I need to know

 

[R-Carpenter]

Yeah, read the book LOL.
Electrical compliance, mechanical/suspension compliance. Basic loudspeaker design. Basically each number tells you how stiff for example mechanical suspension of the driver (spider, surround ) or electrical Q (magnet/voice coil=motor). Total Q is a combination of mechanical and electrical compliance.

Anyone wants to chime in and write a 3 page answer on the Q?

What exactly are you trying to do bud?
I don't mean to be a pest here but the T/S and it's relationship to the loudspeaker performance needs to be researched in order to understand the it.

And it's a coaxial driver with the tweeter crossed over with 1st order crossover (6db roll off per octave) around 10 000 Hz. The crossover consist of the capacitor and may be a resistor.

 

[Joeteck]

Yeah, read the book LOL.
Electrical compliance, mechanical/suspension compliance. Basic loudspeaker design. Basically each number tells you how stiff for example mechanical suspension of the driver (spider, surround ) or electrical Q (magnet/voice coil=motor). Total Q is a combination of mechanical and electrical compliance.

Anyone wants to chime in and write a 3 page answer on the Q?

What exactly are you trying to do bud?
I don't mean to be a pest here but the T/S and it's relationship to the loudspeaker performance needs to be researched in order to understand the it.

And it's a coaxial driver with the tweeter crossed over with 1st order crossover (6db roll off per octave) around 10 000 Hz. The crossover consist of the capacitor and may be a resistor.

Trying to understand what I'm reading when I read these types of specs...