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#1
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Breaking KX-5 VX-5 link
When I proposed inserting a fully balanced Bryston 10B between my KX-5 Twenty and VX-5 Twenty to high-pass to KEF LS50s, Charles Hansen objected, because it might compromise the zero feedback design. I've been discussing this matter on the Bryston board and wonder how to balance the sonic value of zero feedback against relieving the LS50s of low frequency duty. The 10B is sitting in the box unopened. Any thoughts?
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#2
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Having inserted the Bryston 10B between the KX-5 Twenty and VX-5 Twenty for high-pass, the objections of Charles Hansen seem well founded. The high frequency sound is a bit too "HiFi" for my taste. One of the glories of the Ayre stuff is the music just seems to flow. That's no longer the case, so I'll be removing the 10B and work on low-passing the sub to reduce its overlap with the LS50. (The sub controller is driven directly from the unbalanced output of the preamp.)
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#3
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Breaking KX-5 VX-5 link
Bad idea.
Last edited by Blackstone; 07-09-2018 at 09:12 PM. |
#4
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In addition to messing with the magic between your Ayre preamp and amp the 10B will introduce a phase shift in output signals. Best to do as you suggest and test the system frequency response with a sound pressure meter, eg Galaxy Audio CM-140 or better, and computer software such as REW. I found my ears alone cannot be used to setup bass. With sub setup it is best if you can adjust the crossover slope, volume, signal polarity, and crossover frequency. My sub is setup with crossover frequency of 30Hz, 12db/octave, and volume adjusted to blend into the low end of Quad ESL63s (using a 10B on a second output from the KX-5 twenty but you have sub electronics).
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#5
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I should remove the 10B from the balanced preamp-amp link and try using the single-ended outputs of the KX-5 Twenty to drive the LF-pass section of the 10B rather than the the Velodyne SMS-1, perhaps sending the LF-passed output from the 10B through the SMS-1 for acoustic room correction.
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#6
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I purchased my single ended 10B in the early 90s. There are 12 crossover frequencies from 30 to 1k and 6, 12, and 18 db/octave slopes. I ran a wire for each channel in the box to put the volume control on the low pass instead of the stock high pass. Just need to choose polarity so the sub and main speakers are in phase at the crossover. Choose slope for best blend.
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#7
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Quote:
* 70 Hz is the lowest crossover my 10B offers. db |
#8
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Ouch!
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#9
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I've decided to remove the Bryston 10B entirely, and use the Velodyne SMS-1 bass manager to set the low-pass crossover to the subs. I've been reluctant to use the SMS-1 for this because it requires a video monitor, and there are so many parameters that can be set, but a careful reading of the manual suggests I need go no deeper than adjusting the crossover then letting the SMS-1 run in auto mode to do the rest of the setup from its acoustic measurements. Given the LS50s are running full range, I want to creep up to the steep rolloff point to reduce overlap, so I'll start at 50 Hz and leave the slope at the default 24 dB/octave of the SMS-1.
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#10
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Removing the Bryston 10B and using the Velodyne SMS-1 bass manager to low-pass to the subs below 50 Hz restored the Ayre sound and simulates well a high-quality full-range setup.
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