Benefits of phase plugs?

[varkeast]

I never really see this discussed... What differences do phase plugs like the ones used by ascend acoustics make? They seem fairly uncommon and I was just curious what people think about them.

 

[Votrax]

Let me try to put it in layman's terms. The sound wave created by a speaker at the edge of the cone lags the wave from the center by a miniscule amount of time. So these manufacturers add the phase plug which slows down the wave from the center so it's transmitted at the same time as the wave from the edge. You're really splitting hairs with this technology. I personally don't think it will make a discernable difference.

 

[Rip Van Woofer]

I personally don't think it will make a discernable difference.

Yeah, but they look cool! Seas makes woofers with coppery looking phase plugs that are, visually, the cat's heinie.

Just one more arrow in the speaker designer's quiver IMO; something that when appropriately used can help the designer 'dot the i's and cross the t's' so to speak.

I don't recall the exact review but Gene or Hawke reviewed a speaker whose drivers included phase plugs and they did a good job of explaining the principles there. Look thru the speaker reviews.

 

[Votrax]

Yeah, but they look cool! Seas makes woofers with coppery looking phase plugs that are, visually, the cat's heinie.

You're right. They do look cool. I certainly wouldn't steer anyone away from the manufacturers that use them. It's just an additional feature on a quality speaker which I'm sure only added a few dollars to the price.

 

[Audioholics]

I don't recall the exact review but Gene or Hawke reviewed a speaker whose drivers included phase plugs and they did a good job of explaining the principles there. Look thru the speaker reviews.

Gene wrote it, here's an excerpt:

The phase plug essentially eliminates the need for a dust cap, which in turn, reduces cone mass, permitting extended frequency response. It allows more airflow through the motor structure, which improves cooling and thus increases power handling. A Phase plug also helps to reduce on-axis beaming by dispersing higher frequencies that the cone is producing.

Note: Beware, many loudspeaker manufacturers use a quasi phase plug which looks like a phase plug for marketing purposes, but does not physically separate from the cone of the driver. These "so called" phase plugs can do more harm than good as they provide an inconsistent surface area and they also increase mass of the cone yielding poorer frequency response and linearity.