Tweeters with or without fluid?

Funny.  This post is like a time warp.  I haven't heard anyone mention anything about fluid filled tweeters on 15 or 20 years.  Ferrofluid-filled tweeters?  Beautiful.     

You don’t see "ferrofluid cooled tweeter" advertised much anymore, except in cheaper speakers. Being a big Tannoy fan - this topic is intresting to explore in the 2000s era Tannoy lineup, where they used ferrofluid tweeters in the "tulip" DC drivers (lower lines and pro lines) and no-fluid compression chamber / horn tweeters ("pepperpot" DC - dry coils) in the upper half of their top Prestige line.

I have a few of both kinds, and though ferrofluid tweeters are defnitely out of fashion now, those Tannoy ferrofluid tweeters still do GREAT. Haven’t had a problem with one yet, and their treble response actually tends to be a bit smoother and more extended than the pepperpot one. However, the latter DC lends its magic in the midrange, and with its massive efficiency.

At some point I'll have to check on them and clean / replace the fluid, but frankly that seems pretty easy. The magnetic gap will hold it in place. 

I believe Vandersteen still uses ferrofluid in the tweeters of their 2 and 3 Signature speakers.

The tweets in my Kef speakers use Ferro fluid. Yep, it dried out . I cleaned and replaced the fluid. Tweets now sound like new. I did a post on this subject a few years ago. So far so good!

The choice between tweeters with or without cooling fluid (usually ferrofluid) depends on what you're looking for in terms of sound quality, durability, and application.

Tweeters with ferrofluid have better heat dissipation, which helps prevent overheating and improves their lifespan. They also handle more power and tend to have smoother performance because the fluid dampens unwanted resonances. However, ferrofluid can dry up over time, which can affect performance, and some audiophiles feel it slightly reduces sensitivity and detail in high frequencies.

Tweeters without ferrofluid don’t have to worry about fluid drying out, and they often sound more open and natural, especially in high-end audio setups. They can also be more efficient since there’s no damping. On the downside, they don’t handle heat as well, which can lead to more distortion at high volumes and potentially a shorter lifespan.

If you’re using them in a high-power setup like a home theater or PA system, ferrofluid tweeters are usually the better option. If you’re into high-end critical listening and want the purest possible sound, non-ferrofluid tweeters might be the way to go. For general home audio or car speakers, either can work, but ferrofluid tweeters tend to be more durable.