This applet will help
you calculate the specifications for your custom speaker boxes. Read the <A href="./design-help" target="_black">help</A> 
for informations on getting started.<BR> 
<BR> 
<BR> <center>
<APPLET code="linearteam.netisd.common.class" archive="netisd.jar" width="440" height="370"> 
<PARAM name="Fs" value="44"> 
<PARAM name="Vas" value="101"> 
<PARAM name="Qts" value="0.33"> 
<HR><I>Your browser can't run 1.0 Java applets! </I> 
<HR> 
</APPLET> </center><br><hr><br>
	<SCRIPT language="javascript"> 
<!--
var vb=0
var vbin='cubicfeet'
var fb=0
var np=0
var vd=0
var vdinch=0
var vdin='Feets'
var lv=0
var k=0.732
var acp=0
var db=0
var mach=0
var venttype="normal"
 
if (document.images) {
typeoff = new Image();
typeoff.src = "gfx/ventnorm.gif";
typeon = new Image();
typeon.src = "gfx/ventflan.gif";
}
 
function imageon(imageName){
	if (document.images) document[imageName].src = eval(imageName + "on.src");
}
 
function imageoff(imageName){
	if (document.images) document[imageName].src = eval(imageName + "off.src");
}
 
function type() {
	for ( var i=0 ; i<=2 ; i++ ) {
		if ( venttype=='normal' ) {
			k=0.850
			imageon('type')
			venttype='flanged'
			break
		}
		if ( venttype=='flanged' ) {
			k=0.732
			imageoff('type')
			venttype='normal'
			break
		}
	break
	}
}
 
function changevbin() {
	vbin=document.values.vbin.selectedIndex
	if ( vbin==0 ) { vbin="cubicfeet" }
	if ( vbin==1 ) { vbin="liter" }
}
 
function changevdin() {
	vdin=document.values.vdin.selectedIndex
	if ( vdin==0 ) { vdin="Feets" }
	if ( vdin==1 ) { vdin="Centimeters" }
	if ( vdin==2 ) { vdin="Inches" }
}
 
function calculate() {
	vb=document.values.vb.value
	fb=document.values.fb.value
	np=document.values.np.value
	vd=document.values.vd.value
	acp=document.mach.acp.value
	if ( vbin=='cubicfeet' ) {
		vb=(vb*28.31685)
	}
	vb=Math.round(vb)
	if ( vdin=='Feets' ) {
		vd=(vd*30.48)
	}
	if ( vdin=='Inches' ) {
		vd=(vd*2.54)
	}
 
	lv = (((23562.5*(vd*vd)*np)/((fb*fb)*vb))-(k*vd))
 
	if ( vdin=='Feets' ) {
		lv=(lv*0.03281)
		vdinch=(vd*12)
	}
	if ( vdin=='Inches' ) {
		lv=(lv*0.3937)
		vdinch=vd
	}
	if ( vdin=='Centimeters' ) {
		vdinch=(vd*0.3937)
	}
 
	if ( acp != 0 ) {
		mach = ((13.7*(Math.sqrt(acp)))/(fb*((vdinch/2)*(vdinch/2)))/(np*np))/1.254
	}
 
	mach=(Math.round(mach*100)/100)
	lv=(Math.round(lv*1000)/1000)
 
	document.result.lenght.value=lv
	document.result.measure.value=vdin
	document.result.ventmach.value=mach
}
 
//--> 
</SCRIPT> 
 
<STRONG class="headline">Vent calculator</STRONG><BR> 
Vent/Port calculator is designed to calculate the lenght of your
vent(s). Start by typing in these Box-values.<BR> 
<BR> 
Use the Acoustic power calculator for calculating
the acousticpower of your driver. Acoustic power
is needed for calculating Vent Mach.<BR> 
<BR> 
Vent Mach must be below 0.16 for the vents not to
wisthle.<BR> 
<BR> 
<B>Remember</B> to write 0.1 and not 0,1<BR> 
<center><table align=center><tbody><tr><td><FORM name="values" id="Form1"> 
<HR align="CENTER" size="1" width="100&percnt;" color="Black"> 
Vb = Box volume:&nbsp;<INPUT name="vb" size="5" type="text" value="0" id="Text1"> 
<SELECT name="vbin" onchange="changevbin()" id="Select1"><OPTION name="cubicfeet" value="cubicfeet">Cubic Feet</OPTION><OPTION name="liter" value="liter">Litre</OPTION></SELECT><BR> 
Fb = tuning frequency:&nbsp;<INPUT name="fb" size="6" type="text" value="0" id="Text2">&nbsp;Hz&nbsp;&nbsp;&nbsp;-
Number of vents:&nbsp;<INPUT name="np" size="6" type="text" value="0" id="Text3"><BR> 
Vent(s) diameter:&nbsp;<INPUT name="vd" size="5" type="text" value="0" id="Text4"> 
<SELECT name="vdin" onchange="changevdin()" id="Select2"><OPTION name="Feets" value="Feets">Feets</OPTION><OPTION name="Centimeters" value="Centimeters">Centimeters</OPTION><OPTION name="Inches" value="Inches">Inches</OPTION></SELECT><BR> 
</FORM> 
</td></tr><tr></td>
<BR> 
<TABLE align="clearleft" border="0" cellpadding="0" cellspacing="0" width="440" id="Table1"> 
	<TBODY><TR> 
		<TD align="center" valign="top" width="80"> 
			Type of Vent:<BR><BR> 
			<A href="javascript:type()"><IMG name="type" src="./LinearTeam- Vent Calculator_files/ventnorm.gif" width="50" height="50" border="0" alt="Normal or Flanged ?"></A> 
		</TD> 
		<TD bgcolor="#dddddd" width="10"> 
			&nbsp;
		</TD> 
		<TD align="left" bgcolor="#dddddd" valign="top" width="150"> 
			Vent Mach calculation:
			<FORM name="mach" id="Form2"> 
			Acoustic Power of driver:&nbsp;<INPUT name="acp" size="6" type="text" value="0" id="Text5"> 
			</FORM> 
		</TD> 
		<TD align="center" valign="bottom" width="200"> 
			<A href="javascript:calculate()"><IMG src="./LinearTeam- Vent Calculator_files/calvent.gif" width="160" height="30" border="0" alt="Calculate the lenght of vent(s) And Mach of Vent(s)"></A> 
		</TD> 
	</TR> 
</TBODY></TABLE> </td></tr></tbody></table></center>
<HR align="CENTER" size="1" width="100&percnt;" color="Black"> 
<FORM name="result" id="Form3"> 
<B>Results:</B><BR> 
Length of each vent:&nbsp;<INPUT name="lenght" size="6" type="text" readonly="" value="0" id="Text6">&nbsp;<INPUT name="measure" size="11" type="text" readonly="" value="Measurement" id="Text7"><BR> 
Vent Mach :<INPUT name="ventmach" size="6" type="text" readonly="" value="0" id="Text8">&nbsp; ( Must be below 0.16 for not wisthling )
</FORM> 

<br><hr><br>
	<SCRIPT language="javascript"> 
<!-- 
var qts=0
var vas=0
var fs=0
var qms=0
var pe=0
var no=0
var ac=0
var vasvol="Cubicfeet"
var qes=0
 
function changecubic() {
	vasvol=document.values.cubic.selectedIndex
	if ( vasvol==0 ) { vasvol="Cubicfeet" }
	if ( vasvol==1 ) { vasvol="Liter" }
}
 
function calculate() {
	qts=document.values.qts.value
	vas=document.values.vas.value
	fs=document.values.fs.value
	qms=document.values.qms.value
	pe=document.values.pe.value
	if ( vasvol=="Liter" ) {
		vas=(vas*0.03531)
	}
	qes=(1/((1/qts)-(1/qms)))
	no=(((fs*fs*fs*vas)*0.000000027)/qes)*100
	ac=(no*pe)/100
	ac=(Math.round(ac*100)/100)
	document.values.acpower.value=ac
}
 
function graph() {
	if ( vasvol=="Cubicfeet") {
		var graph = window.open('gfx/graphfeet.gif', 'Acousticpowergraph', 'toolbar=0 , location=0 , directories=0 , status=1 , menubar=0 , scrollbars=0 , resizeable=0 , width=650 , height=470')
	}
	if ( vasvol=="Liter" ) {
		var graph = window.open('gfx/graphmeter.gif', 'Acousticpowergraph', 'toolbar=0 , location=0 , directories=0 , status=1 , menubar=0 , scrollbars=0 , resizeable=0 , width=650 , height=470')
	}
}
 
//--> 
</SCRIPT> 
 
<STRONG class="headline">Acoustic power claculator</STRONG><BR> 
The acoustis power of a driver is used to see how loud the driver can
play in a certain roomsize. Start by typing in your drivers Thiele/Small.<BR> 
<BR> 
<B>Remember</B> to write 0.1 and not 0,1<BR> 
<BR> 
When Acoustic Power has been calculated. Remember the value and
click to view this <A href="javascript:graph()"><B>graph</B></A><BR> 
When graph is opened, go up the Y-axis to the number of your Acousticpower.
Now you must go out the X-axis to your desired roomsize. Compare
this point to the 80, 90 &amp; 100 db.-lines to see how loud your speaker
can play in your room.<BR> <br>
<FORM name="values" id="Form1"> 
Qts:&nbsp;<INPUT name="qts" size="6" type="text" value="0" id="Text1">&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Vas:&nbsp;<INPUT name="vas" size="6" type="text" value="0" id="Text2">&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<SELECT name="cubic" onchange="changecubic()" id="Select1"><OPTION name="cubicfeet" value="Cubicfeet">Cubic Feet</OPTION><OPTION name="liter" value="Liter">Litre</OPTION></SELECT><BR> 
Fs:&nbsp;&nbsp;&nbsp;<INPUT name="fs" size="6" type="text" value="0" id="Text3"> Hz&nbsp;
Qms:&nbsp;<INPUT name="qms" size="6" type="text" value="0" id="Text4">&nbsp;
Pe:&nbsp;<INPUT name="pe" size="6" type="text" value="0" id="Text5"> Watts<BR> 
<BR> 
<A href="javascript:calculate()"><IMG align="middle" src="./LinearTeam-Acoustic Power Calculator_files/calculate.gif" width="160" height="30" border="0" alt="Calculate the Acoustic power of driver"></A><BR> 
<BR> 
<INPUT name="acpower" size="6" type="text" readonly="" value="0" id="Text6"> 
</FORM>