T/S specs for SR woofers? (6500 and 5250)

Vital

Are there T/S specs available for SR6500 and SR5250 woofers?

Vital

I should really use google before even making new threads like this one lol, nevermind, found it.
I guess while we are at it - can someone please explain to me what this voodoo means? haha

SR5250
http://www.polkaudio.com/caraudio/specs/recent/sr5250/

Thiele/Small Parameters
Resonant Frequency 71 Hz
Qms 8.28
Qes 0.78
Qts 0.72
Vas 0.2073 Cu. Ft., 5.87 L
Cms 490 Micro Meters
Bl 4.6 Tesla Meters
Sd 14.33 sq. in., 92.46 sq. cm.
Xmax (linear) 0.1
Xmax (mechanical) 0.362
Le .25 mH

SR6500
http://www.polkaudio.com/caraudio/specs/recent/sr6500/

Thiele/Small Parameters
Resonant Frequency 60 Hz
Qms 10.3
Qes 0.7
Qts 0.65
Vas 0.4 Cu. Ft., 11.3 L
Cms 440 Micro Meters
Bl 5.6 Tesla Meters
Sd 21 sq. in., 135 sq. cm.
Xmax (linear) 0.16
Xmax (mechanical) 0.32
Le 0.38 mH

arun1963

http://www.bcae1.com/ This is a good site if you want simple explanations on technical stuff.

Meanwhile:

1. Resonant Frequency: Also called Fs. This is the frequency at which your speaker will show the highest impedence and response of the the driver typically rolls off below this point. There is a more technical description in terms of energy, moving mass etc but this is the gist. The larger the cone (hence greater moving mass) the lower this frequency.

2. Q numbers: These are measurements of the damping ability of the speaker. Qms measures the mechanical damping, Qes is for electrical damping and Qts is the combined (mechanical+electrical) damping for the speaker. Typically speakers with a Qts of under 0.5 will do better in smaller enclosures. Qts of 0.5 and higher can be run free air / IB like in your typical door.

3. Vas : A measure of the stiffness of the suspension with the driver mounted in free air. Looked at another way it means that for the SR-5250 an enclosure more than 0.20 cu ft would be considered free air. A larger number ,means the suspension is less stiff and hence requires a bigger enclosure.

4. Sd: Surface area of the cone.

5. Xmax : The total distance that the cone can movein one direction. Based on the height of the voice coil winding and the height of the magnetic gap. Within this max range is the linear range where the cones excursion stays liner. Put another way, Xmax = peak power and Xlin = RMS power on an amp.

6. Le: Measures the inductance of the voice coil. In a 2 way, your mid bass will play both the MB and the mid range. A lower Le number roughly means that it will play the midrange frequencies better and with greater details than a driver that has a higher Le number. While the SR6500 is great with mid range when compared to almost any 6.75" driver, the SR5250 with a lower Le number will do the mid range better. Mac will confirm that.

Vital

Thank you Arun!!
I guess this is what I need to look into a bit more:

2. Q numbers: These are measurements of the damping ability of the speaker. Qms measures the mechanical damping, Qes is for electrical damping and Qts is the combined (mechanical+electrical) damping for the speaker. Typically speakers with a Qts of under 0.5 will do better in smaller enclosures. Qts of 0.5 and higher can be run free air / IB like in your typical door.

3. Vas : A measure of the stiffness of the suspension with the driver mounted in free air. Looked at another way it means that for the SR-5250 an enclosure more than 0.20 cu ft would be considered free air. A larger number ,means the suspension is less stiff and hence requires a bigger enclosure.

I'm trying to see what would be the most ideal enclosure for SR5250 woofer as I'm planning my SR 3-way.
I currently have 6500 woofer in my doors, tweeters in mirror cover area. 5250 are kinda big to be mounted in my kickpanels so I need to come up with placement and enclosure.

Now onto .20 cu ft to be concidered free air for 5250: ok, so we have our minimum. What's maximum?? Or in other words how big is "too big"?

MacLeod

Nope. Since they're designed to work in infinite baffle like your door panels, it won't matter once you get over a certain point. In this case, .2 ft3 like Arun said.

Vital

So 5250 will sound the same in 0.2 ft3 as in let's say 6.4 ft3 and even 15.2 ft3 ??

MacLeod

It should cause there will be a point where the speaker will be strong enough (for lack of a better word) to overcome the air space. Less than a certain amount and it restricts the speaker. Above a certain amount and there isn't enough pressure to restrict it. I'm sure there is a much more technical answer but that's the way my small brain looks at it.

ipartywhenuhurt

Awesome lots learned XD u guys are awesome ivebeen wondering this for months about how big to make it free air

Vital

Wait... so if I make sealed enclosure for SR5250 that is 0.3 ft3 i'm all good, right?

arun1963

Vital wrote: »

Wait... so if I make sealed enclosure for SR5250 that is 0.3 ft3 i'm all good, right?

Yes.

Vital

arun1963 wrote: »

Meanwhile:

1. Resonant Frequency: Also called Fs. This is the frequency at which your speaker will show the highest impedence and response of the the driver typically rolls off below this point. There is a more technical description in terms of energy, moving mass etc but this is the gist. The larger the cone (hence greater moving mass) the lower this frequency.

If I understand it correctly it's basically in other words - that's how low speaker can go without any distortion.
If so - then why is it that frequency responce is 40Hz for 6500 and 60Hz for 5250 when resonant frequencies are 60 and 71??

arun1963

Vital wrote: »

If I understand it correctly it's basically in other words - that's how low speaker can go without any distortion.

No, Fs is not about distortion, but frequency response. The amplitude will roll off sharply below this frequency. It will still play 50hz but at reduced db levels. The rising impedence on the speaker will limit excursion, hence lower db's.

Thom

I think making an enclosure for them is a bit unnecessary. In order to get .3, assuming that will, in fact, sound "best" you need about 8x8x8ish (or 10x10x5ish). I don't know how big your kicks are but I think after making sealed enclosures your mids will be sticking into your footwells way more than needed. If you make some baffles that seal up to the steel of the car and let the woofers breathe into those cavities you'll save yourself some work, the kicks will look much better, and your stage should be wider.