Buzzing sound
It is not just some minor buzzing it is a remarkable resonance as the membrane just hanging loose at that frequency.
It is not just some minor buzzing it is a remarkable resonance as the membrane just hanging loose at that frequency.
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.
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.
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.
One month and still not confirmed any replacement
Still not received any confirmation that BG will replace the faulty unit(s) after a month today.
Informed by BG that they investigate the shipment cost, and been so for a month now. If these cost low enough I will receive a new unit if not I am not sure what will happen ??
Strange.
Still not received any confirmation that BG will replace the faulty unit(s) after a month today.
Informed by BG that they investigate the shipment cost, and been so for a month now. If these cost low enough I will receive a new unit if not I am not sure what will happen ??
Strange.
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Hi larss,
For Santa, sell the clowns, buy the clones....
look at the bottom of this link : Iris Strassacker, solutions HiFi plus de 500 kits d'enceintes à votre choix : Audiopur Mag100M
Sold in a serious shop with european guarantee even if the product is from... India from Jodhpur ? China ?
For Santa, sell the clowns, buy the clones....
look at the bottom of this link : Iris Strassacker, solutions HiFi plus de 500 kits d'enceintes à votre choix : Audiopur Mag100M
Sold in a serious shop with european guarantee even if the product is from... India from Jodhpur ? China ?
I have no idea of what the Genesis 1.2 XO frequency might be, but I hope somewhere around 3-4 kHz, or no higher.
It's an interesting system which I have never heard, but I assume that is sadly not suitable for near-field listening because of all the tweeters and their interference pattern, and the very wide baffle will require a long listening distance for the RD-75.
I've worked a lot on different baffle shapes and widths for the RD-75, and have found that there are really only two ways to do it - no baffle like I did myself, or a very wide baffle like the Genesis 1.2. Something in between will not work well. The bass is also monopole, while the midrange is dipole, which will create integration problems between the wide baffle and the woofer towers.
Oh, and here's the 1.2
It's an interesting system which I have never heard, but I assume that is sadly not suitable for near-field listening because of all the tweeters and their interference pattern, and the very wide baffle will require a long listening distance for the RD-75.
I've worked a lot on different baffle shapes and widths for the RD-75, and have found that there are really only two ways to do it - no baffle like I did myself, or a very wide baffle like the Genesis 1.2. Something in between will not work well. The bass is also monopole, while the midrange is dipole, which will create integration problems between the wide baffle and the woofer towers.
Oh, and here's the 1.2
An externally hosted image should be here but it was not working when we last tested it.
Baffle width another approach
Hi Stig Erik
Take a look at the Gryphon speaker Pendragon
Gryphon Pendragon
which use a slotted baffle of 0,5m, and 4pcs AMT tweeters crossover at 18kHz.
Interesting approach. Their "RD75" seams not to be BG as looks different.
I use at the moment a 10cm one side baffle just for testing but it help to get a smoother frequency response. May test a 15cm slotted on both sides and AMT tweeters
Hi Stig Erik
Take a look at the Gryphon speaker Pendragon
Gryphon Pendragon
which use a slotted baffle of 0,5m, and 4pcs AMT tweeters crossover at 18kHz.
Interesting approach. Their "RD75" seams not to be BG as looks different.
I use at the moment a 10cm one side baffle just for testing but it help to get a smoother frequency response. May test a 15cm slotted on both sides and AMT tweeters
I have read that the greatest advantages of dipolar radiation patterns are in the bass region, yet convenience seems to win and as a result most bass systems are monopolar, even when the midrange is open baffle or dipolar.
I can't help but notice that the most significant raves regarding quality of bass reproduction seem to be for dipolar woofers, large bass horns and distributed subwoofer systems of the type used by Dr. Earl Geddes, yet I have not had the luxury of hearing any of these types.
I can't help but notice that the most significant raves regarding quality of bass reproduction seem to be for dipolar woofers, large bass horns and distributed subwoofer systems of the type used by Dr. Earl Geddes, yet I have not had the luxury of hearing any of these types.
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