T/S parameters how do they change with 2 drivers

[endrek]

How my values of Qts,Fs,Vas,etc (T/S parameters) will change if i make a normal placement of 2 drivers in paralel instead of just one. Do the formulas change? Do the parameters change?

Fs atleast has to change and get higher right??But how much?Any formulas'??

i know its easy to just let the simulator do it for you, but i would like something more Or know where to find more information

thanks!!!

[endrek]

Originally Posted by endrek

How my values of Qts,Fs,Vas,etc (T/S parameters) will change if i make a normal placement of 2 drivers in paralel instead of just one. Do the formulas change? Do the parameters change?

Fs atleast has to change and get higher right??But how much?Any formulas'??

i know its easy to just let the simulator do it for you, but i would like something more Or know where to find more information

thanks!!!

in bassreflex box preferly to know

[planet10]

Qt, Fs are the same
Vas doubles

dave

[endrek]

but then, if i want to design a double driver in a bass reflex box.

How would you proceed to do the design?

-Calculate the T/S parameters for the 2 drivers as you said? and then proceed to do the calculations for the box as a unique driver???

thx for your help

[planet10]

Just pretending that the 2 drivers are one works, some sim programs let you enter the number of drivers and take care of it for you

dave

[18Hurts]

I was looking at an Electro Voice spec sheet

They claim that when two of their pro drivers are use, Fs goes down. Not a lot, say a pair of 34 Hz Fs drops to 33 Hz but I found it interesting. Since Fs varies from spec sheets anyway, always best to test the pair etc. before you design a box.

[weltersys]

Originally Posted by endrek

How my values of Qts,Fs,Vas,etc (T/S parameters) will change if i make a normal placement of 2 drivers in paralel instead of just one. Do the formulas change? Do the parameters change?

Fs atleast has to change and get higher right??But how much?Any formulas'??

i know its easy to just let the simulator do it for you, but i would like something more Or know where to find more information

thanks!!!

As 18Hurts mentioned Fs goes down slightly with multiple cones in close proximity.

The driver parameter changes when used in multiples are far less than the influences room response, port resonances, and directivity will have on the actual frequency response.

Don’t sweat the small stuff.

[endrek]

Originally Posted by 18Hurts

I was looking at an Electro Voice spec sheet

Th. Since Fs varies from spec sheets anyway, always best to test the pair etc. before you design a box.

testing like this?
===> if i do something like this, but changing the 10Ohm R for a 4 Ohm R (because the 2 drivers in paralel equal to 4Ohms), and after, calculating the T/S parameters with the two drivers wired in paralel, will i be able to know how the T/S parameters change? and then be able to calculate the box with those values?

Could it be possible? Any considerations to do it? Or i'm just dreaming too much?
Thanks again for all

Set up diagram


by the way i found this at this forum )
================================================
If
"a" is the number of elements that are connected in series, electrically,
"b" is 1 for normal configuration, 2 for isobaric configuration and
"n" is the total number of elements, the new values are calculated as:

Vas=Vas1*n/b^2
Bl=Bl1*a
Sd=Sd1*n/b
Re=Re1*a^2/n
Le=Le1*a^2/n

So two drivers in series, side by side has a=2, b=1, n=2 and
Vas=2*Vas1
Bl=2*Bl1
Sd=2*Sd1
Re=2*Re1
Le=2*Le1

====================================

[endrek]

just one stupid question,
i thought that if you mount two drivers togther there is +db right? then if you do the graphic Y=dB and X=Freq, if the edge of curve increases, the frecuency goes up, right?

[endrek]

someone posted this
================================================== ================

as far as i know having two drivers is the same as having one except you double the box/port sizes. eg the gsub can be split down the middle and each half modelled as a 160l box with tunning of 40hz (i've been told, not my calcs) and someone else told me that for AJ designer (another peice of software) that you simply double the VAS of one driver to model a box for two of the same driver.
================================================== ==================

is it correct? can i just calculate a bassreflex for the half of the Gsub size, and then double it?

And maybe do a little bit longer the ports just in case it need some trim to tune it?


thx again for you help