subwoofer build help

Jump to Latest
P

phoenix87

Member
Joined 2010
#1
Hi all ,
i am planning on making a passive subwoofer for my home setup , i have shortlisted the following drivers

1. Peerless 12inch aviable from Varsha electronics with the following specs
Peerless Fabrikkerne (I) Ltd - 12" Sub-Woofer
Features: Coated paper cone with durable foam surround.
Stamped Powder coated Chassis.
Technical Specification:
Parameter Value Unit
RMSE - Free 0.43 Ohms
Fs 25.01 Hz
Re 3.68 Ohms
Res 9.69 Ohms
Qms 1.17
Qes 0.45
Qts 0.32
L1 0.53 mH
L2 1.11 mH
R2 6.09 Ohms
RMSE - Load 1.01 Ohms
Vas (SD) 256.35 Liters
Mms (SD) 59.71 Grams
Cms (SD) 678 uM/Newton
BL (SD) 8.80 Tesla-M
SPL ref (SD) 94.7 dB [Re]
Rub -Index 0.14
Xmax mm
Area (SD): 518.75 Sq.Cm
Impedance 4 Ohms
Frequency response 26 - 220 Hz
Method: Mass loaded - Mmd (100 Grams)
DCR Mode: Fixed (3.68 Ohms)

2.IWAI SUB-WOOFER 12” 4Ω 200W with Shorting Ring
Electrical
Nominal Impedance 4 Ohms
Resonance Frequency 25 Hz
Power Handling {IEC-268-5C} 200 Watt
Long Term Power {IEC-268-5L} 600 Watt
Short Term Power {IEC-268-5S} 1000 Watt
Sensitivity (2.83V/1m) 91 dB
Resistance (DC) 3.5 Ω
Qms 6.91
Qes 0.43
Qts 0.41
BL 14.23 T-M
VAS 86.57 Litres

Mechanical
Voice Coil Dia 50 mm
Winding Width 32.60 mm
Former TIL
Layers 4
Wire Type Copper
Magnet 134 mm
Cone Material Paper
Surround Material Rubber
Chassis Powder Coated
Dust Cap Paper

I have simulated both the driver in WINISD and found that the IWAI one has a -3db roll off at 44hz where as the peerless one has a roll of at 54hz ....
Both being a sealed box of 44L and 66L respectively , Can anybody share their views regarding the choices made above

Regards
 
#5
I agree with snappyTurtle. Also the IWAI has higher BL, so a stronger motor. (both are not spectacular woofers). I think it's hard to get Dayton in India like the LS12-44, RSS315HO-44 or UM12-22. But there are some car subwoofer brands like Pyle, Lanzar, Pioneer etc that can be a good alternative for building high power home subs that go low with higher xmax and BL.
 
#6
Hi All,

FYI:

b🙂
 

Attachments

  • iwai_Subwoofer-12inch_calc.JPG
    iwai_Subwoofer-12inch_calc.JPG
    903.3 KB · Views: 286
#7
hi bjorno ,
thanks for helping me out . i got the specs corrected from the manufacturer

Electrical
Nominal Impedance 4 Ohms
Resonance Frequency 25 Hz
Power Handling {IEC-268-5C} 200 Watt
Long Term Power {IEC-268-5L} 600 Watt
Short Term Power {IEC-268-5S} 1000 Watt
Sensitivity (2.83V/1m) 91 dB
Resistance (DC) 3.5 Ω
Qms 6.91
Qes 0.43
Qts 0.405
BL 14.23 T-M
VAS 86.57 Litres
Xmax +- 12mm
SD 522sq cm

I dont quite understand all that you have shown , in the attached image as i am a novice .. from what i could understand is
Ported Box Vb - 96.888L
Sealed Box vb - 42.224L
I arrived at very similar number using winisd alpha , but the port velocity goes very high >20m/sec , using two 3.5inch port of approximately 16inch length ..
Attached winisd alpha file .. and the subwoofers mechanical diagram ...

Regards
 

Attachments

#8
The Peerless does look more like a 'normal' woofer than a sub. Mms (SD) 59.71 Grams is fairly light. The IWAI at ~triple the weight is more typical.

The efficiency specs for both seem a bit high. Using this calculator:

mh-audio.nl - Home

The Peerless is 91.3dB
The IWAL is 86.8dB

...which could be important for a passive setup.

Based on your other posts, your mains are ~89dB, also 4 ohm, and you are using a 30 watt amp. If this is still the case, the Peerless looks like the better fit to your system, even if it won't go quite as low.
 
Last edited:
#9
hollowboy said:
The Peerless does look more like a 'normal' woofer than a sub. Mms (SD) 59.71 Grams is fairly light. The IWAI at ~triple the weight is more typical.

The efficiency specs for both seem a bit high. Using this calculator:

mh-audio.nl - Home

The Peerless is 91.3dB
The IWAL is 86.8dB

...which could be important for a passive setup.

Based on your other posts, your mains are ~89dB, also 4 ohm, and you are using a 30 watt amp. If this is still the case, the Peerless looks like the better fit to your system, even if it won't go quite as low.
Click to expand...

thanks for the pointers , but I have ordered the iwai subs ,now the problem arises with simulation In WINISD alpha it say for chevyshev alingment it gives a box volume of 92.53L with tuning frequency of 24.29hz and at f3 ~ at 23.8hz . with this kind of a box size i am getting port dimensions as 2 X 3.5inch X 24.23inch with a max port velocity of 20m/sec at 20hz with 1st port resonance at 279.22hz.
this same speaker when modelled in bass box pro 6 gives very different results box volume of 74.81L and FB at 23.16hz and f3 at 23.77hz and port dimensions are 2x3.5inch x 34 inch and max port velocity at 19m/sec at 14hz with 200w of power and has a +6db bump at 40hz in the amplitude response graph ??

why are the 2 software modelling the box differently...
 
#11
phoenix87 said:
hi bjorno ,
thanks for helping me out . i got the specs corrected from the manufacturer

Electrical
Nominal Impedance 4 Ohms
Resonance Frequency 25 Hz
Power Handling {IEC-268-5C} 200 Watt
Long Term Power {IEC-268-5L} 600 Watt
Short Term Power {IEC-268-5S} 1000 Watt
Sensitivity (2.83V/1m) 91 dB
Resistance (DC) 3.5 Ω
Qms 6.91
Qes 0.43
Qts 0.405
BL 14.23 T-M
VAS 86.57 Litres
Xmax +- 12mm
SD 522sq cm

I dont quite understand all that you have shown , in the attached image as i am a novice .. from what i could understand is
Ported Box Vb - 96.888L
Sealed Box vb - 42.224L
I arrived at very similar number using winisd alpha , but the port velocity goes very high >20m/sec , using two 3.5inch port of approximately 16inch length ..
Attached winisd alpha file .. and the subwoofers mechanical diagram ...

Regards
Click to expand...

Hi phoenix87,

You're correct about the calculated Box Volumes.

I don't use WinISD and never will..

FYI:New Calculations revealing the new value of Sd=522cm^2 will result in 'inconsistency ' when checking against the other submitted Parameters.

b🙂
 

Attachments

  • iwai_Subwoofer-12inch_New-calc.JPG
    iwai_Subwoofer-12inch_New-calc.JPG
    953.3 KB · Views: 111
  • iwai_Subwoofer-12inch_New-Ported+LT-calc.JPG
    iwai_Subwoofer-12inch_New-Ported+LT-calc.JPG
    758.7 KB · Views: 140
#12
bjorno said:
Hi phoenix87,

You're correct about the calculated Box Volumes.

I don't use WinISD and never will..

FYI:New Calculations revealing the new value of Sd=522cm^2 will result in 'inconsistency ' when checking against the other submitted Parameters.

b🙂
Click to expand...

Thank you for helping again , So the box volume with the SD of 492 sqcm comes to 96.888L and the port dimensions as i back calculated from the port area of 200sq cm and volume of 12.7L as mentioned in the files you attached comes to Port Diameter - 16cm and length - 60.96cm ... is this correct ?
So if i keep the volume i.e 12.7L constant and change my port diameter based on the pipes locally available to me it should work ??

regards
Phoenix
 
#13
Hi Bjorno,
i came across this page written by Troels Gravesen where he explains in details the effect of putting damping material inside a ported box and its effect on vent tuning ...So in effect he is saying damping works the same way as it works in a sealed box , i,e making the box look larger to the driver in his experiments he is saying that a ported box with stuffing will require 0.6 to 0.7 X the actual calculated port length to achieve the requite port tuning frequency.So if that is true , I can effectively make a smaller box put damping in to make it look larger and still use the calculated port length ...Is there any calculation that predicts how much will be the effective increase in box volume with stuffing ??
http://www.troelsgravesen.dk/vent_tuning.htm

and looking again at the webpage ... it seems the writer of the web-page refers to you .... wow that's a nice coincidence .. Bjorno can you please tell me if what I am thinking is correct ..

Regards
 
You must log in or register to reply here.
Top Bottom