B&G RD-75 dipole - baffle and or waveguide? - Page 15 - diyAudio
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Old 28th October 2012, 06:38 AM   #141
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Probably 1-2 dB more.
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Old 28th October 2012, 10:35 AM   #142
lolo is offline lolo  France
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I went all the way to Norway yesterday to listen to Stig Erik system. The only two things I can say it's that he is a really nice guy, and that his system is bloody great! It's much more impressive in reality than pictures.
I own the Orions, they still are great speakers, but this is something different.. Guys, buy a pair of RD-75 as soon as you can..
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Old 28th October 2012, 02:34 PM   #143
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Good to know. I've had a Svalbard trip in mind for some time and was thinking to shoot Stig Erik a PM if it ever turns out I'm in Scandanavia.
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Old 4th December 2012, 12:05 AM   #144
opc is offline opc  Canada
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Hi Guys,

I just received my pair of RD75 planars from PE over the weekend, and I'm excited to start measuring, testing and building!

I have access to a large anechoic chamber and some very good measurement gear, so I plan to run a full gamut of tests on these to see how they measure up. I'm particularly interested in THD performance and characterizing the 5kHz resonance.

Although I'm very intrigued by the idea of a dipole implementation, my listening space really isn't going to work very well for that as I don't have any space between the loudspeakers and rear wall. As a result, I'll be building an enclosure that follows the suggestions in the white paper as closely as possible (10" deep, 6" wide, very well braced and damped).

Has anyone here tried a sealed enclosure? Any success or suggestion?

StigErik:

A while back in this thread or your other one, you mentioned that one of your two ribbons was buzzing, and that you were looking at returning it. After that, you never really mentioned it again.

Can I ask how you resolved the issue? One of my two ribbons is buzzing about 1/3 of the way down form the top at frequencies between 1 and 3 kHz. I was running 1kHz tones to see if I could get a rough frequency response in-room and noticed it right away. It's less noticeable with music, but it's still there.

Did your buzz go away with time, or did you exchange your driver? I checked the driver closely and don't see any signs of damage, but I did notice the foam in the rear outlets was a bit uneven. I carefully straightened it with some plastic tweezers, thinking maybe it was contacting the diaphragm, but it didn't help.

Any suggestions on this would be appreciated

I'll keep everyone posted on the results.

Cheers,
Owen
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Old 4th December 2012, 06:07 AM   #145
ds23man is offline ds23man  Netherlands
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I ordered a pair of RD-50's and will use them as monopole.
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Old 4th December 2012, 06:30 AM   #146
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Quote:
Originally Posted by opc View Post
StigErik:

A while back in this thread or your other one, you mentioned that one of your two ribbons was buzzing, and that you were looking at returning it. After that, you never really mentioned it again.

Can I ask how you resolved the issue? One of my two ribbons is buzzing about 1/3 of the way down form the top at frequencies between 1 and 3 kHz. I was running 1kHz tones to see if I could get a rough frequency response in-room and noticed it right away. It's less noticeable with music, but it's still there.

Did your buzz go away with time, or did you exchange your driver? I checked the driver closely and don't see any signs of damage, but I did notice the foam in the rear outlets was a bit uneven. I carefully straightened it with some plastic tweezers, thinking maybe it was contacting the diaphragm, but it didn't help.
I did not return the drivers - too costly to ship them back and forth across the Atlantic.

I never really found the real source of the buzzing, but I discovered that applying pressure to the front waveguide stopped it. It seems that the buzzing has little to do with the ribbon itself, but rather a mechanical problem with the waveguide. Anyway - installing a clamp solved the problem....

I friend of mine who also has RD-75's solved it this way:
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Old 4th December 2012, 07:43 AM   #147
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Quote:
Originally Posted by opc View Post
Hi Guys,

I just received my pair of RD75 planars from PE over the weekend, and I'm excited to start measuring, testing and building!

I have access to a large anechoic chamber and some very good measurement gear, so I plan to run a full gamut of tests on these to see how they measure up. I'm particularly interested in THD performance and characterizing the 5kHz resonance.

I'll keep everyone posted on the results.

Cheers,
Owen
Wow, sounds fabulous!
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Old 4th December 2012, 08:02 AM   #148
lolo is offline lolo  France
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Quote:
Originally Posted by StigErik View Post
I did not return the drivers - too costly to ship them back and forth across the Atlantic.
Hi Stig Erik, I am afraid I have to give up on the Rd-75, it's just too much risk for too much dosh.. But, I might well take the RD-40 instead.. Should work ok on top of two 18" crossed around 300hz?

One thing though that "bugs" me is the non constant source size depending on distance.. I know, I am asking too much!
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Old 4th December 2012, 08:25 AM   #149
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With any line source you have to optimize frequency response and woofer integration (delay/distance) for a given listening distance.

A rather sexy solution with the RD-40 could be to use four 10" long-throw woofers, two below and two above the RD-40. The Seas L26ROY that Linkwitz use in Orion and LX521 would work very well.
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Old 4th December 2012, 08:51 AM   #150
lolo is offline lolo  France
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Yep, thought about it too! The baffle would have to be strong though, these drivers are rather heavy.. and I can imagine some serious vibrations too. With the first option I could still hang the planars on the ceiling.
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