Subwoofer calculation by means of WinISD

Author: to

In this article I want to tell and show Sobich Aleksej to font about that as it is possible for to calculate a subwoofer and on what it is necessary to pay attention, at design in the following programs: WinISD 0.44, WinISD 0.50а7 .
Calculation of a box will be Audiobahn 1051T is made for ten-inch we Will begin! We start the WinISD 0.50a7 program />/>

1. We create the new project (New Project).
2. Having pressed this button we choose the loudspeaker from base of the program.
3. Viewing Т/С of parameters. />/>

4. Т/С parameters. We press further (Next)

5. Choice of number of loudspeakers.
6. Installation type. />

Normal - all loudspeakers stand on one panel. to

to

Isobaric loudspeakers face the person.

pressed further (Next)

7. Efficiency of loudspeaker. Shows to what type of the case approaches more.
8. A choice such as a box. to

the Closed box – the name tells for itself

to

to

of Fazoinvertorny – a box equipped with a pipe (fazoinvertor).

of Gangs a pass of the 4th order – the loudspeaker is between two chambers one of them has a fazoinvertor.

of Gangs the pass of the 6th order – is between two chambers both are equipped with fazoinvertor.

the Passive radiator – in one closed box the loudspeaker and a passive radiator (the loudspeaker without a magnet)

Is chosen p what type suits us and we press further (Next)

Further the program offers a way of registration of AChH in the various ways. I do not point attention at this point and I press further.
If to choose the Passive radiator that the program to suggest to enter following Т/С parameters of a passive radiator: />

1. of Vas is the raised closed volume of air the loudspeaker.
Fs
2. - resonant frequency.
Xmax
3. - the maximum course of a diffuzor.
QMS
4. – Mechanical good quality.
SD
5. - the diffuzor area.

we will consider Further the program on an example of Gangs a pass of the 4th order.

Driver Tab.

9-10. Again it is possible to specify quantity and type installation of loudspeakers.
11. Additional possibilities.
Box Tab. />/>

12-13. Box chambers
14. Chamber volume.
15. Frequency of setup of the chamber.

the Vents Tab (Fazoinvertor (ы)) />/>/>/>

16. Fazoinvertor's number (ов)
17. Diameter of Fazoinvertor (ов)
18. Fazoinvertora (ов)
19 is long. Type round or rectangular. it is possible to change нав for a circle.
20. Type of a fazoinvertor. />/>/>/>

we Pass to the basic box calculation:

21. We press on schematically shown box the right button of a mouse holding we move the cursor on an axis (X-th) father-in-law across we change volume on an axis (Y) down to change frequency. Similarly Left button of a mouse to change parameters of the bottom chamber. The top of a curve should be above the red line between 35Гц and 120Гц if it is a subwoofer as it is possible more widely and more exactly.

Transfer function magnitude

. AChH
/>

Approximately so, but the bottom limit 40Гц, and top 113Гц, it too approaches. There where I marked br with red hyphens in practice there frequency will be cut off by a crossover.

we Choose the schedule: Maximum Power. to Maximum Power

to

On this schedule the program shows to br the maximum capacity concerning frequency. It is visible that there is a capacity recession recession peak the 60th watt on 39 hertz in practice to a diffuzor of loudspeaker there is no course (Xmax) and there are unpleasant sounds – distortions. On a finished article it it is necessary to consider and limit too capacity

we Choose Maximum SPL schedule

Maximum SPL

. This schedule shows the maximum sound pressure to

it is Also visible recession. For the same reason. the Last two schedules from other loudspeaker, I showed them that was more evident.
Here schedules for our experimental. A little improbable on frequency from 0 Hz and to 25 Hz all loudspeakers have the first recession. />

should decide Now by

on the sizes of a box in which the loudspeaker is established.
for this purpose we start the WinISD 0.44 program we press the new project. />

to us should enter parameters of our loudspeaker into this program since. in its base it is not present for this purpose we press «New»
we Will pass to WinISD 0.50a7 />

22. Having pressed this button it is possible to see Т/С parameters which should be entered into WinISD 0.44.

we Enter parameters it is pressed OK and we close this window that it was not stirred.
we Create the new project. />

23. We rearrange a tick to choose the loudspeaker.
we Press further, and we do just as and in WinISD 0.50a7 />

we Transfer box parameters from WinISD 0.50a7 to WinISD 0.44.
/>

24. We press to start to count the size of a box.
25. We press and the program gives out optimum in her opinion the sizes.
on hand we have 10 inch loudspeaker its full external diameter of 300 mm to find room for it in a box the sizes W and D there should not be less than 300 mm
26. Width we enter 300мм 0,300 METERS
30 equal. It is possible to change units of measure simply having pressed dimension in this case the letter "m"
28. Length we enter 0,300 meters
27. We press «H» the program shows height.
31. To pay attention to L1 and L2 it is height of chambers it is necessary to look that depth of insert of loudspeaker did not exceed L2 value.
But it will be necessary to consider thickness of a material it внахлест in a nutria there is a shelf in which costs the loudspeaker and its thickness too to consider the loudspeaker it after all too borrows we beat him I already considered if a box big there inside there should be their struts it is necessary to consider too. 7 details to calculate correctly details turn out it is necessary to consider that any of them will be нахлестываться т.к the program shows internal diameters. The letter "P" I will be укалывать thickness of a material which should be added to other values.
1) the D x W
2) the D x W
3) the D x W
4) H + (P*3) x D
5) H + (P*3) x D
6) H + x W (P*3) + (P*2)
7) H + x W (P*3) + (P*2)
we Receive the sizes of details if thickness of a material 20мм:
1) 300х300 2) 300х300
3) 300х300
4) 420х300
5) 420х300
6) 420х 340
7) 420х 340 />/>/>/>/>/>/>/>/>/>/>/>/>/>/>/>/>/>/>/>/>/>

can be passed Now br to fazoinvertor calculation.

32. Fazoinvertor type we will use rectangular
33. It is long. When the end of a fazoinvertor is displaced with a box wall
that it is virtually extended, and actually it turns out that it is adjusted not on that frequency and bigger WinISD 0,44 of it are long does not consider virtual lengthening it is possible to calculate most on a formula but it is simpler to glance in the WinISD 0.55a7 program
I repeat: it is valid only when the end of a fazoinvertor is displaced with a wall of a box and when he acts it does not operate. So the WinISD 0,44 program shows 28,86см and WinISD 0,55а7 25,64см. Ф the fazoinvertor will be established in a detail No. 4 420х300 from 420 taken away 20 it is height of a fazoinvertor is received exactly 400 т.к a fazoinvertor rectangular one more detail 8) 300х255 Here final the size of details
I their quantity is added.
1) 300х300
2) 300х300
3) 300х300
4) 400х300
5) 420х300
6) 420х340
7) 420х340
8) 300х255 />/>/>/>/>/>/>/>/>/>/>/>

34. Resistance of air. In a fazoinvertor it is necessary to do resistance of air increasing the area of an opening of a fazoinvertor as little as possible.

Many thanks of "Sobich Aleksej" for article

/> !>