long xmax: pros and cons

[sokolasty]

AFAIK

pros: high power before farting

any cons?

 

[broerevb]

most long-xmax drivers are sub speakers, and don't have much mids... So adding a mid cone is a good idea.

 

[smo]

The major con, is a less precise sound. Sort of.
The further the speaker moves - theoretically - the more air it will move = more power.
BUT - the more the speaker moves, the less likely the speaker is able to reproduce any given frequency at any precise micro-second in time, due to the fact it's already currently vibrating at some considerable speed.

Obviously, the better quality the speaker you have will reduce this effect - but in general, theoretically, the larger the Xmax, the more muddy the driver will be.
BUT (there's always a but) This effect will only be minimal, and I wouldn't choose any given driver solely on the Xmax value.
There are far too many other parameters to think about.
Like Watts for one!

IME - the Xmax will only have a bearing on whether you decide to port the cab or keep it sealed.

smo

 

[broerevb]

The major con, is a less precise sound. Sort of.
smo

Hm, quite the opposite I think. When a speaker exceeds it's x-max, the voice coil leaves the magnet gap, and so there is less control over the speaker.

Where's the diy legion to shine a light on this?

 

[sokolasty]

Where's the diy legion to shine a light on this?

One of them started the thread.

 

[sokolasty]

IME - the Xmax will only have a bearing on whether you decide to port the cab or keep it sealed.

smo

What do you mean by that? Drivers with long xmax work better in sealed or vented enclosure?

 

[billfitzmaurice]

AFAIK

pros: high power before farting

any cons?

Potentially lowered durability. Xmax is the distance the voice coil can travel within the gap while response remains linear; xlim is how far the coil can travel before damage occurs. A good rule of thumb is for xlim to be about twice xmax, allowing for a large margin of overshoot without damaging the driver. If xmax is extended without a corresponding increase in xlim then the potential for driver damage is increased.

There are far too many other parameters to think about.
Like Watts for one!

Pe is the most often quoted driver spec, but is one of the least significant.

IME - the Xmax will only have a bearing on whether you decide to port the cab or keep it sealed.

I wouldn't say that at all, although a driver mounted in a sealed cab would require a longer xmax to achieve the same output as one mounted in a Vb of the same size, as the Vb would have higher LF sensitivity and minimal excursion at Fb.

 

[smo]

A good rule of thumb is for xlim to be about twice xmax, allowing for a large margin of overshoot without damaging the driver. If xmax is extended without a corresponding increase in xlim then the potential for driver damage is increased.

Learn something new everyday.
Thanks Bill.

 

[billfitzmaurice]

Learn something new everyday.
Thanks Bill.

Many owners of one particular sub driver found out the hard way. A 1,000 wattt rating and 18mm xmax made it look almost indestructable, but with only a 22mm xlim coil damage was only a matter of time.

 

[sokolasty]

So, AFAIU, there are no cons regarding sound, there is only durability issue. So why there are that few drivers with long xmax?