High Pass Filter for Cone Excursion

[mmoeller]

Is it ok to use a low order high pass filter to controll cone excursion of a vented driver, below the tuned vent frequency?

[JohnL]

I've seen car audio guys do it on subs (not that that has anything to do with high fidelity audio reproduction).

[ThomasW]

HT-Guide member, Chas98 was working on one. If he doesn't reply to this thread send him a PM or email

[BobEllis]

Some guy named Neville Thiele suggested doing just that back in the late 70s/early 80s. I'd take that as a yes.

[chasw98]

I'm here. And I built an 18 db (I think) per octave active filter at 17 Hz for use with my sub in the beginning. I found it is not nessecary to use one with a driver that is built for the sub enclosure and amplifier properly sized for ordinary use. What enclosure size, driver brand and model number, and amplifier are you going to be using? How many watts at what impedance? Let me know. I can give you some tips on building them and some links to circuits.

Chuck

[Jack Gilvey]

It's almost a given on vented subwoofers, but how about full-range designs?

[ThomasW]

It's almost a given on vented subwoofers, but how about full-range designs?

If the design is vented and being used without a sub, I think it's a good idea.

[mmoeller]

I was kind of open ended with my question. I was looking at a 3 way set up with 2 or 3 small mid-woofers vented for some bass extension. The drivers quickly went out of control with only a +/- 5.5mm Xmax.

Peerless Nomex 6.5"

http://www.madisound.com/cgi-bin/in....16380&pid=1958

With a 3 driver set up in a 85L box, tuned to about 40Hz I get pretty decent extension. I added a 2nd order Butterworth at 20Hz to control excursion. I have attached a picture of the WinISD plots for refernece. These excursions were using 100W.

I'm aware that the 3 driver set up will most likely not be practical due to the nominal 8 ohm impedance.