question about push-pull designs (1 Viewer)

[Alexis]

Hi,

What are the actual gains from a push-pull driver encloser like what M&K uses? Provided that you do not increase the enclosure size and simply the enclosure for a single driver.

I understand that the drivers will move air in the same direction so they do not cancel each other out, but what gains do you get from this setup? My thought is to either have a sealed box design with a push-pull, or a sonotube (sized for one driver) with another driver on top acting in a push-pull config.

Thanks

 

[Jim A. Banville]

Supposedly it smooths out non-linearites in the cone movement.

 

[Ron D Core]

I've made a couple Isobaric push/pull type sub boxes for cars (I'm not sure how it applies to home audio) and the only benifit worth utilizing in my opinion is the small enclosure size. The improved linearity is generally not noticable by most people. Its all a matter of opinion like most things, but I wouldn't bother. You can run the same driver in a larger box with half the power and get basicly the same sound.

 

[Tim Hood]

~6dB...

Tim

 

[Jim Robbins]

Distortion cancelation is the main plus for push-pull and also iso-barik (along with the volume being halfed). I used to think the M&K was the one to beat but I have heard several single driver subs best it so why bother with two drivers.

 

[Dustin B]

Hopefully Jack G will come in here soon. I can't find his old post on this. There is a difference between a push pull and an isobaric design. Isobaric has air trapped between the drivers, air inside the box and air outside the box. A push pull doesn't trap any air. There is just the air inside the box and the air outside the box.

 

[Alexis]

Right, Isobaric has two air trapped between the two drivers and an enclosure around one or both the the other ends of the drivers.
I am curious about the push pull designs that look just like a regular sub, except you have an additional driver on one end of it. Like this:

 

[ThomasW]

Push-pull designs cancel the even and odd order harmonics produced by the drivers