Help with push-pull subwoofer design - Kenwood KFC-W2500

Status
Not open for further replies.
Hi,

I have a pair of these Kenwood KFC W-2500 10inch subwoofers, specs as below. Currently one of them in a 60L ported box tune to about 32Hz. Another one was doing nothing.

I am thinking about using these to design a push pull subwoofer design. But unfortunately WINISD dont offer features for designing push-pull systems. Anyone can help me out here? Specs as below

10" woofer; Kenwood KFC-W2500, Peak Power 360W.

Fs = 28hz
Vas(FT^3) = 2.67
Vas(m^3) = 74.19
QMs = 11.228
Qes = 0.337
Qts = 0.327
Pmax = 360
Re = 3.51
Xmax = 21.31
Sensitivity(db@1w/1m) = 91
 

Attachments

  • kenwood front.jpg
    kenwood front.jpg
    29.9 KB · Views: 574
  • kenwood back.jpg
    kenwood back.jpg
    31.2 KB · Views: 382
If I am correct (entirely possible that I'm not) you just need to design an enclosure 'normally' - i.e. work out enclosure volume(s) and tuning for the two drivers.

How you mount them (in or out) is effectively moot, bar the small increase in internal volume brought about by removing the cone, basket and magnet assembly, and the differing wiring layout needed.
 
That design is Dual Opposed rather than Push Pull, unless you reverse one of the drivers and run it basket-out. In that example you'd just wire each of them up the same - they both push out at the same time, they just happen to be on different sides of the box.


In a Push-Pull the wiring is effectively out of phase, I think - when one pulls towards its basket, the other pushes away from its basket. If they are single voice coil drivers, you'd run cables as follows:

Driver 1
amp + to driver +
amp - to driver -

Driver 2
amp + to driver -
amp - to driver +


I think...

It gets more complicated with dual voice coil drivers!


You could also consider a Push Pull Slot Loaded (PPSL) design if you have the additional space required and/or inclination to try it!
 
In a Push-Pull the wiring is effectively out of phase, I think - when one pulls towards its basket, the other pushes away from its basket. If they are single voice coil drivers, you'd run cables as follows:

Driver 1
amp + to driver +
amp - to driver -

Driver 2
amp + to driver -
amp - to driver +

Yes, that is correct. On the front panel, one cone faces outwards while the other driver has the magnet facing out.

Wire the cone facing out as normal, amp+ to driver+. For the magnet facing out, wire amp+ to driver-.

In use, both cones will move out at the same time. One pushes (cone facing out) while the other pulls (magnet facing out).

there's no way the Xmax of that driver is "21.31 mm".

That's an error. Xmax is 4.95mm

hi dannyjmf
I modeled the W2500 in your existing 60L box tuned for 32Hz. The box can accommodate 2 units of W2500 with the same tuning. Just F3 moved up slightly higher.

Regards
Mike
 

Attachments

  • KENWOOD KFC-W2500_60L.gif
    KENWOOD KFC-W2500_60L.gif
    38.4 KB · Views: 316
  • KENWOOD KFC-W2500 x2_60L.gif
    KENWOOD KFC-W2500 x2_60L.gif
    36.8 KB · Views: 306
Push/Pull has nothing to do with whether it's ported or sealed. It can be used in both.

The main advantage with Push/Pull is lower distortion. Since one is pushing while the other is pulling, the distortion kind of cancels out.

My experience with Push/Pull is rather limited. Compared to normal cone facing front, I can't tell the difference. Maybe it was just the wrong drivers. My guess is Push/Pull really shines when it is powered near the max.

.... so far i being with ported box but never satisfied with their bass transient responses

Bass transient is a tricky one. I like to think of it as the Attack in the bass notes. This attack is in the mid-bass. If I want good bass attack, I will use a 8", rolling off at between 80Hz-125Hz. I then support it with another driver for the lower bass (40Hz).

This time i am going to build a sealed push pull design. Will there be any noticeable differences?

Yes, there will be differences. However, I doubt it will give you the bass transient that you're after.
 
1)BTW is there really any advantages of push pull designs over ported boxes?
2)Will there be any noticeable differences?
1) Advantages are reduction of even order harmonic distortion and reduced frontal baffle area, if desired. Some driver's rear vents make objectionable noise which can be more objectionable than even order harmonic distortion.
2) No noticeable differences in transient response. The upper resonant peak in a slot loaded PP may be perceived as adding "presence", but I EQ it out 😉.
 
If I could jump in here with a question real quick, just to clarify the idea in my head before I go trying a PPSL. If you make a BR type PPSL, should you locate the port inside the slot as well, or somewhere else on the cabinet?
 
Status
Not open for further replies.