I have been told that I do not need to tune my sub below 30hz due to the high SSF on my 500watt bash AMP. What does that mean?

A rumble filter was a high pass in the old days for LP listening.The motion of the needle would cause the bass driver to oscilate and that would cause distortion in the midrange because the bass driver was busy traveling peak to peak trying to reproduce the travels of the needle.

So, the rumble filter would rolloff the bass from, like , 25hz and below......I think :D

The reason to not tune the sub below 30hz is because the rumble filter is a high pass filter, so those low sounds it's going to roll off anyways. It would be more benificial to tune it higher so that those sounds are produced better than trying to produce the low sounds better which will be rolled off anyways.

Thanks that helps alot

So what is the SSF of the Bash 500watt Plate amp (from PE). And is there a way to change it to a lower setting.

Most of the PE amp webpages have a link to a document that shows what resistor values need to be changed to adjust the frequency of the filter.

I asked this about the 300 watt BASH amp in another thread, but this one is much more appropriate.

Is this subsonic filter the same thing as the stock settings as listed on the boost sheet (http://www.partsexpress.com/pdf/300-750.pdf) (G=+1dB, Fc=17.7Hz, Q=1)? I do understand that a bass boost will make the low end roll off faster which I assume acts as a rumble filter. Am I way off base here or is there some other mechanism in the amp at work?

Im kinda with boomie on this one. Questions ?s ?s

So if I use the boost chart from PE (Bash 500 watt amp boost chart) (http://www.partsexpress.com/pdf/300-752.pdf) (1db chart) that means by changing the r17 to a 27 K ohms and my r18 to a 100 than my filter will let me go down to 13.9hz.

Is that correct. And if so, should I make sure the filter does not go below my Fs of my sub.

Is that correct. And if so, should I make sure the filter does not go below my Fs of my sub.it's okay if it goes below the Fs, just make sure it doesn't reach maximum excursion at that frequency.

Just to restate what Gir_1337 said above, because I have some interest in your project from the former thread: the driver's Fs is the resonant frequency of the driver itself but not a limitation to enclosure tuning frequency. There may well be tones produced by the combination of driver and port that go below Fs, but this territory must be fully explored using your WinISD charts. Cone excursion is to be looked at closely, but you have a long-excursion driver to work with and should be able to work the box into some low tuning. Experiment with several variants, all the while looking at each of the other graphs to see what differences the changes make.

How would one go about interpreting the slope of the filter?

*Edit* I've figured it out and used unibox and other related apps and its all good.