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Old 3rd September 2012, 03:44 PM   #11
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Quote:
Originally Posted by SpinMonster View Post
Thanks for all the great responses. Is there any benefit to the 75 over the 50 other than low end extension, power handling?

How do you set up an active notch filter for the 4k or so peak with a DCX?

Would a 400hz 4th order cross be ok for the RD50 to 2 RS180's?
The peak is at ~5.5 kHz.

400 Hz 4th order surely is ok. I run my own RD-75's down to 180 Hz with 4th order XO.

RD-75 does not have more LF extension that RD-50. The only difference is impedance, power handling and height of the wavefront. The latter means that the RD-75 is true line-source lower in frequency that the RD-50.
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Old 4th September 2012, 04:31 AM   #12
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Originally Posted by StigErik View Post
The peak is at ~5.5 kHz.

400 Hz 4th order surely is ok. I run my own RD-75's down to 180 Hz with 4th order XO.

RD-75 does not have more LF extension that RD-50. The only difference is impedance, power handling and height of the wavefront. The latter means that the RD-75 is true line-source lower in frequency that the RD-50.

My room is 21x21 but I as worried about the listening distance with the bigger 75. Its a home theater too. I like the close perspective. Its a 16 foot diag screen. This isnt the greatest picture of set-up but maybe you can extrapolate.

Click the image to open in full size.
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Old 4th September 2012, 04:32 AM   #13
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I figured the 50 would allow a closer seat at 2m.

More like 2.5m actually.

Last edited by SpinMonster; 4th September 2012 at 04:36 AM.
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Old 4th September 2012, 05:44 AM   #14
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I sit 1.2 meters away from my RD-75's. Any distance really is OK as long as you can EQ the frequency response to fit the desired distance.
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Old 4th September 2012, 07:40 AM   #15
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Originally Posted by StigErik View Post
I sit 1.2 meters away from my RD-75's. Any distance really is OK as long as you can EQ the frequency response to fit the desired distance.

Does it just roll off the highs being close or is it a really ragged response?
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Old 4th September 2012, 02:11 PM   #16
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Quote:
Originally Posted by SpinMonster View Post
Does it just roll off the highs being close or is it a really ragged response?
What happens is that the response below 700 Hz changes (for the RD-75). This is because the driver is not a true line-source below 700 Hz.

At shorter distance you may get too much level below 700 Hz, but that again depends on baffle size when using the driver as a dipole.

"It all depends" is the universal answer for almost everything I guess....
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Old 4th September 2012, 05:33 PM   #17
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Im not sure if its been addressed before but would an array of 6 NEO8PDRs per side have an advantage to the RD50? It seems efficiency, power handling, top end extension, and likely ultimate SPL would be enhanced while low end extension is bumped a bit to 500hz 4th order elect.

It also moves the resonance to 12K.

Is there anything Im missing as far as the physics of the two different arrays?
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Old 4th September 2012, 06:37 PM   #18
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The Neo8 is almost 20 dB down at 20khz, so there is certainly not more top end extension compared to RD-50. And off-axis it's far worse, since the Neo8 is wider than RD-50.
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Old 5th September 2012, 05:03 AM   #19
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The Neo8 is almost 20 dB down at 20khz, so there is certainly not more top end extension compared to RD-50. And off-axis it's far worse, since the Neo8 is wider than RD-50.

Thanks.

Its initial desirability was that its expandable to additional drive units.

I wish I could hear the 50 & 75.

Anyone willing to demo their system for a nice lunch?
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Old 7th September 2012, 11:46 AM   #20
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How about for $100
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