Re: 4pi's on the way! [message #76694 is a reply to message #76693] |
Wed, 08 May 2013 14:33 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to previous message](/forum/theme/AudioRoundTable/images/down.png) |
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Wayne Parham
Messages: 18752 Registered: January 2001
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Illuminati (33rd Degree) |
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Plate amps are convenient, because they let you do everything in one box. The only problem with them is most do fourth-order slopes, some do third but I've only seen one that does second-order and I generally prefer that for flanking subs. We want a gentle low-pass rolloff that makes the flanking sub act like the helper woofer in a 2.5-way speaker, just detached so it can be placed in a different axis in all three planes.
The only plate amp I've seen that supports second-order slopes is the RBA CA-200. There may be others out there, but I haven't seen them. And I haven't tested the RBA amp, so I can't comment on its quality, just the fact that it is advertised to provide second-order low-pass.
That's why I've always run separate amps and crossovers. It gives more flexibility to change low-pass frequency and slope. There are a handful I've used. Here are a list of some:
The last four are all the same unit, rebranded by different companies. It's actually a cheesy little car sub crossover, but when upgraded as shown in the "Pyle" link above, it is quite good. And of course, you can also use something like MiniDSP.
One last option, that may be worthwhile, are the RCA inline filters, with 100Hz and 120Hz second-order slopes. I haven't tried them though, and I am concerned that they may act differently with different source and load impedance values. So I hope to make time to check them out someday soon, because they would be convenient options if they worked well.
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