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Old 28th November 2013, 07:57 PM   #1421
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Default Buzzing sound

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Originally Posted by StigErik View Post
Ok, so you have a buzzing sound from the RD-75's? You're not the only one. This seems to be a common problem with these drivers.

It is not just some minor buzzing it is a remarkable resonance as the membrane just hanging loose at that frequency.
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Old 28th November 2013, 08:46 PM   #1422
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Since I don't have a pair of RD-75s, nor an open baffle array of multiple cone woofers, I can't do this experiment–but if I did, I would.

I'd hook an unmounted RD-75 up to a microphone preamplifier and record its output while it was functioning as a microphone, which I'm sure it would do quite well. Then I would play music (especially with some bass content) through the woofer array at medium-loud levels while I moved the RD-75 from a position close to but not touching the bass panel (and in the null zone) to touching the edge of the bass panel, listening to the results with appropriate headphones* or recording the results in some way. Through the process, if recording, describe verbally the position of the ribbon in relation to the bass panel. As I mentioned in an earlier post a couple of pages back, this would be to satisfy my curiosity as to the source of these resonances–i.e., are they self generated, or are they in response to acoustic excitation from the LF drivers.

*I would use my Etymotic Research ER4s (in ear monitors) with shooters' hearing protectors over them. this gives about 60dB of attenuation of ambient sound.
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Old 28th November 2013, 09:02 PM   #1423
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Default Rd 75 lost tensioning

I have not any bass unit/speakers at the moment, I am only listening to the RD75 units. Crossover set to 250hz, 24db.

Plan is to combine the RD75 with Ken Kreisel subwoofers when I get some working unit(s).

Last edited by Larss; 28th November 2013 at 09:08 PM.
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Old 29th November 2013, 09:47 PM   #1424
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Default Resonance

[QUOTE=Russell Dawkins;3717899]I've never heard the B&G RD75, but the last long ribbon I did hear (in the Carver Amazing loudspeakers) had exactly this problem. The resonances were all-too-obvious with piano and then, once identified, could be heard on lots of other material. I guessed the problem was ineffective damping of the ribbon, coupled perhaps with trying to make it perform down to frequencies it was not really capable of. The resonances I was hearing were at frequencies between 400 and 3,000 Hz at a guess–right in the middle of the important stuff!


The resonance is so obvious and certainly affect all played music. I am not happy with the B&G units and their quality at the moment. I am not even sure that they perform any measurements or quality control of the units before shipment as no QA document is coming with the units. We who buy these units have spent years of eveluating speakers and different brands, types of speakers etc. to reach what we are looking for , music nirvana. I hoped that BG should put me there. Now it is up BG to handle this issue in a proffesional manner. I really hope that I will end up with two fantastic units that bring audio nirvana to my living room. If so, I will definately inform of that event.
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Old 30th November 2013, 03:30 PM   #1425
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Quote:
Originally Posted by Larss View Post
Now it is up BG to handle this issue in a proffesional manner. I really hope that I will end up with two fantastic units that bring audio nirvana to my living room. If so, I will definately inform of that event.
If one try to orient one self around the different web sites this company has + the way they do business it looks more like a business lawyer company than a passionate hi-fi company. The way it looks to me the original designer are either overrun by investors or has never joined the boat. Looking forward to hear your result.
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Old 30th November 2013, 03:58 PM   #1426
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I am sure you got a monday sample. Ask for repair!
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Old 1st December 2013, 03:50 PM   #1427
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I really hope you get it fixed. The RD-75's are wonderful sounding drivers when they are free from buzzing and other problems. I absolutely love them, but it's sad to read that B&G obviously have serious quality control problems.
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Old 1st December 2013, 08:13 PM   #1428
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Default Genesis 1.2 crossover freguency RD75/tweeter

Anyone, what is the crossover frequency between the RD75 and tweeters in the Genesis 1.2 speaker?
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Old 16th December 2013, 01:47 PM   #1429
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Default Amplifiers for the RD75

Any recommendations for amplifiers for at great match with the RD75?

What are you using.
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Old 16th December 2013, 01:50 PM   #1430
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I'm using Hypex Ncore amps for both the RD-75 and woofers.
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