Originally Posted by noah katz
I thought it doesn't chop them off, it just doesn't allow direct manipulation.
Why doesn't LTD's workaround work for you?
Correct - it doesn't chop things off if the highpass isn't applied. Since I run a tapped horn sub that needs a highpass when pushed (and I have been known to push things), a proper highpass isn't optional. My larger tapped horns (including the one I am listening to) all require lower highpass filters than the current implementation of the iNuke 3000DSP software can do.
I've tried stacking filters, LTD02's approach works fine, but it results in a 2nd order slope, which isn't quite steep enough for me, I can still manage to get myself into trouble.
Also - the shallow slope doesn't really gain me much, because I'm not moving the corner all that much lower than the factory limit, so when done, it's really about the same as the result I get with a higher-order 20 Hz highpass.
If I recall, Ricci tweaked multiple filters to get closer to a 4th order slope at about 14 Hz, but that took trial and error effort and measuring, which is something I have not had much time for lately.
Since this whole setup is temporary, and I regularly grab the amp for testing other stuff, I'll readily admit that I have just punched the easy button, set it at 20 Hz, with as steep a slope as possible, and rolled with it. Might be leaving a bit on the table, but at the moment, I'd rather be watching movies than messing with DSP settings. I'm convinced that the 20 Hz lower limit in the iNuke DSP software is arbitrary, based on the perceived "limit" of human hearing. It could be set lower without significant effort, simply change the lower limit of the variable. At least in the case of the MiniDSP, once above 10 Hz, the DSP doesn't care, a biquad is a biquad.
As far as other folks? Accurate measurements of amp response can be a challenge, I've let the smoke out of a few sound cards in the process, and I sorta know what I am doing. I wouldn't recommend a multiple-filter approach without measurements, and not everyone can do that. That's why I said "some folks" above. Not everyone can measure their junk to make this work. It is far easier to just push a button, click a mouse, or twist a knob.
Honestly - this is a software limitation, it can be a software fix. Such a fix would turn the iNuke DSP, which is already a good series of products into what would be some truly great choices for home theater use, and the change would have zero impact on the other uses of the amp. Seriously, we're talking about up to 2 KW/4ohm/stereo of power at less than $500 street? And that price includes a fully-functional integrated DSP that has no gain-structure issues and incorporates some of the coolest limiters I've ever played with? Sign me up, I'll wave in a pair today!!!
Before I do - what's the catch, because this sounds a bit too good to be true???
Oh, yeah, I can't apply any filters below 20 Hz without tricking the software, and that is a kludge at best. This limitation may not matter to most of the people that buy the iNukeDSP amps, but it matters a lot to me, as well as a lot of the other nutjob regulars here.
Even with this fundamental limitation, I own and use an iNuke 3000DSP.
With my current sub, I'm not missing too much. I still have a couple years until I need to worry about equipping my proper theater, we'll see what is available when that time comes. I will still need a highpass, and I can just about guarantee that the iNuke DSP's 20 Hz limit will mean that an octave is left on the table, which is unacceptable to me. At that time, I'll do my homework and choose the right tool for the job at hand.