Home Theater Forum - View Single Post - Recommendations for mid-bass suplementation of planars...

RichardHOS · 04-26-2003, 07:58 PM

Thanks... definitely a lot of good information there. After seeing how you approach the numbers, I think increasing the midbass/subbass crossover point would be an easy way to reduce driver requirements. I have no problem with redirecting frequencies of around 60Hz or even a bit higher to the front IB system, I was just concerned about the 100Hz+ information.

When I indicated "flat from 40Hz to 150Hz+" that was really just giving myself an allowance below the crossover point (and, actually, above as well) to ensure the driver remained flat in the passband range. I'm glad you put some numbers to my instinct - an octave below XO minimum.

Using the information you provided I'll start a search for appropriate drivers. Looks like the XO's are going to be a pain. A high pass for each surround channel to send highs to the planars, a low pass for each surround channel to send mid/lows to the sealed enclosure, and an additional low pass for each channel to send sub/lows to the front IB. Throw in the possibility of another high pass per channel to keep sub frequencies out of the mid/low sealed enclosure.

If I could find an XO that has a high pass and low pass for a single channel (or, even a common crossover point that separates the channel into a high and low pass output), then I'd need 8 channels worth - just for the surrounds. Another three channels for the front.

One more question... how difficult would it be to forgo the high pass XO to keep sub frequencies out of the midbass sealed inclosure, and just use an appropriate driver/enclosure design that naturally rolls off at the correct point? That would simplify things somewhat.

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04-26-2003, 07:58 PM	#5 of 8
RichardHOS Member Join Date: Mar 2003 Local Time: 06:05 PM Local Date: 12-02-2008 Posts: 463	Thanks... definitely a lot of good information there. After seeing how you approach the numbers, I think increasing the midbass/subbass crossover point would be an easy way to reduce driver requirements. I have no problem with redirecting frequencies of around 60Hz or even a bit higher to the front IB system, I was just concerned about the 100Hz+ information. When I indicated "flat from 40Hz to 150Hz+" that was really just giving myself an allowance below the crossover point (and, actually, above as well) to ensure the driver remained flat in the passband range. I'm glad you put some numbers to my instinct - an octave below XO minimum. Using the information you provided I'll start a search for appropriate drivers. Looks like the XO's are going to be a pain. A high pass for each surround channel to send highs to the planars, a low pass for each surround channel to send mid/lows to the sealed enclosure, and an additional low pass for each channel to send sub/lows to the front IB. Throw in the possibility of another high pass per channel to keep sub frequencies out of the mid/low sealed enclosure. If I could find an XO that has a high pass and low pass for a single channel (or, even a common crossover point that separates the channel into a high and low pass output), then I'd need 8 channels worth - just for the surrounds. Another three channels for the front. One more question... how difficult would it be to forgo the high pass XO to keep sub frequencies out of the midbass sealed inclosure, and just use an appropriate driver/enclosure design that naturally rolls off at the correct point? That would simplify things somewhat.