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View Full Version : Lowering subsonic filter to 15 from 30 Hz on the BSS FDS 360s



diamondsouled
10-26-2008, 03:34 PM
Just wondering if it is worthwhile changing the subsonic filter on the FDS 360 to 15 instead of 30 Hz.

Cheers

Larry

Robh3606
10-26-2008, 06:40 PM
Hello Larry

Well how low do you want to go?? If you are trying to get response to 20hz in the sub channels then obviously it would be something you want to do.

Rob:)

Allanvh5150
10-26-2008, 11:43 PM
Ask yourself this question. How low do my cabinets go? If they dont go below 30Hz it will have little benefit. From memory the roll of on the Brooke Siren was quite gentle anyway.:)

diamondsouled
10-28-2008, 11:16 AM
I'll be running Fane Colossus 18Bs in the bins so I suppose it might possibly be worth it.

Lar

Allanvh5150
10-28-2008, 11:57 AM
Probably not. I just ran the numbers and with a pair of drivers in a 400L box tuned to 30 Hz, the output down that low is not huge. These drivers seem more suited to run around 50Hz with high output. As an example for you, the Fane in an optimised box for flatness, the 3db down point is around 63Hz. A JBL 2245 in the same type of cabinet, optimised, the 3db down point is a round 35Hz. Of course with a little tweaking both drivers will go a bit lower. Hope this helps. :)

diamondsouled
10-28-2008, 03:29 PM
Probably not. I just ran the numbers and with a pair of drivers in a 400L box tuned to 30 Hz, the output down that low is not huge. These drivers seem more suited to run around 50Hz with high output. As an example for you, the Fane in an optimised box for flatness, the 3db down point is around 63Hz. A JBL 2245 in the same type of cabinet, optimised, the 3db down point is a round 35Hz. Of course with a little tweaking both drivers will go a bit lower. Hope this helps. :)

Thanks Alan!

I have a chance to pick up a pair of 180 Hz cards, would they be better to use with the Fanes than the 100Hz ones that come with the 360s?

Lar

Allanvh5150
10-29-2008, 12:39 AM
What do you plan on running above the Fanes?

diamondsouled
10-29-2008, 02:12 AM
What do you plan on running above the Fanes?

Depends. I plan on trying both a two way set up as well as a three way set up.

I have some extra Heil AMTs around which I'd like to hear working with the Fanes but that would be crossed over at 1.2k Hz.

For a three way set up I have some small Elite mid bins for above 100 Hz as well as some 077s for above 6k Hz.

I have a variety of tube amps to use for the bi-triamping so the possibilities will be interesting.

Lar

boputnam
11-05-2008, 09:42 AM
Hi, Larry...
Just wondering if it is worthwhile changing the subsonic filter on the FDS 360 to 15 instead of 30 Hz.I agree with Allan's take...


Probably not. I just ran the numbers and with a pair of drivers in a 400L box tuned to 30 Hz, the output down that low is not huge. These drivers seem more suited to run around 50Hz with high output. As an example for you, the Fane in an optimised box for flatness, the 3db down point is around 63Hz. A JBL 2245 in the same type of cabinet, optimised, the 3db down point is a round 35Hz. Of course with a little tweaking both drivers will go a bit lower. Hope this helps. :)

The frequency response from 18B 600 brochure (see imbed) shows this woofer rolls-off pretty steep after 50Hz. Changing the subsonic filter would only sap power without increased satisfaction on your part. :) If you want more from that portion of the frequency range, you should consider an alternative driver, or perhaps a true "sub" to augment only that range.