RD75 Break-in
BG Quote:
"You’ll notice several stages of break-in with the long line drivers:
#1 First 2 hours of play time they’ll start to smooth out.
#2 24-40 hours they will be hard on start up, but smooth out very quickly – 5 minutes.
#3 60-100 hours they will be smooth and engaging.
#4 200+ hours become quite liquid and truly palpable.
I hope this helps so enjoy those transitions."
BG Quote:
"You’ll notice several stages of break-in with the long line drivers:
#1 First 2 hours of play time they’ll start to smooth out.
#2 24-40 hours they will be hard on start up, but smooth out very quickly – 5 minutes.
#3 60-100 hours they will be smooth and engaging.
#4 200+ hours become quite liquid and truly palpable.
I hope this helps so enjoy those transitions."
Definately wrong
At some frequencies, for example piano, the membran resonance and it sounds just awful.
The membrane seams to lost its tensioning. It is more prominent on one unit but I have not shift channels so it may also show up on the other unit.
First it was the glue issue, refer to earlier posts, and now it is this tensioning issue.
I am now in direct contact with B&G, and we will see how they solve this issue.
At some frequencies, for example piano, the membran resonance and it sounds just awful.
The membrane seams to lost its tensioning. It is more prominent on one unit but I have not shift channels so it may also show up on the other unit.
First it was the glue issue, refer to earlier posts, and now it is this tensioning issue.
I am now in direct contact with B&G, and we will see how they solve this issue.
Sorry to hear about this. I was planning to purchase a pair of these drivers as well. Your experience has given me pause.
I assume you got a replacement for the original one with bad glue?
Do both drivers exhibit the same resonance? Can you give details of your measurement setup? Any additional information would be appreciated.
Thanks
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!
Another possibility I have not been able to test is that the ribbon, being mounted in the same baffle as the 4 -12" woofers and adjacent to them, might have been tossed around by the severe pressure fluctuations caused by the woofers. If I had been in a position to experiment, I would like to have tried it with the ribbon removed from the baffle–even by a small amount to see if positioning the ribbon in the null of the OB bass array would have the effect I would expect.
Stig, do you ever listen to solo piano, and are your ribbons free of obvious resonances? I ask because he is the only one I know using the ribbons detached from the baffle with the LF drivers–although I am sure there are many others.
Lost tensioning
I was sent an additional unit to replace the one with the bad glue.
The resonance is so prominent that it does not need to be measured to understand that something definately wrong here. However, I have the Dirac Live room correction software and when performing a frequency sweep I can clearly hear when the resonance show up during the sweep and the Dirac room correction can not deal with this resonance after calibration.
I was sent an additional unit to replace the one with the bad glue.
The resonance is so prominent that it does not need to be measured to understand that something definately wrong here. However, I have the Dirac Live room correction software and when performing a frequency sweep I can clearly hear when the resonance show up during the sweep and the Dirac room correction can not deal with this resonance after calibration.
Larss,
Do you have any way to preform a quasi-anechoic measurement? I don't think it's fair to make such determinations without removing the room effects. I've seen some pretty nasty looking measurements taken without gating.
Part Express does not gaurante Radia drivers outside USA anymore...
That's the second buzz....... pfff my short list was NEO 10 + ? (TPL 150H) vs 50 rd (because shorter). i think it will be a Neo 10 and a ? above 2k hz...
Or a NEO 8s >500 to <7000 + Neo 3 rdp but a radia 50 would be less ewpensive in Q/P and waf enough...
That's the second buzz....... pfff my short list was NEO 10 + ? (TPL 150H) vs 50 rd (because shorter). i think it will be a Neo 10 and a ? above 2k hz...
Or a NEO 8s >500 to <7000 + Neo 3 rdp but a radia 50 would be less ewpensive in Q/P and waf enough...
Last edited:
RD75 Magnets does not cover all length of membrane !
Another issue may be that the magnets, the full length of the magnets, cover different length of the membrane on the two units. Seams very strange.
At the units ends (upper part and bottom part) the magnets does not reach all the way up and all the way down of the membrane, and it is different on the two units how far up and down the magnets reach, several cm?
When put together a unit wouldn't it be natural to start and finish the magnets at same places along the unit.
Anyone with any input here ?
Another issue may be that the magnets, the full length of the magnets, cover different length of the membrane on the two units. Seams very strange.
At the units ends (upper part and bottom part) the magnets does not reach all the way up and all the way down of the membrane, and it is different on the two units how far up and down the magnets reach, several cm?
When put together a unit wouldn't it be natural to start and finish the magnets at same places along the unit.
Anyone with any input here ?
Buzzing sound
The buzzing sound is acc to BG related to that the membrane may loose tension during freight, and is not so common acc to BG.
The buzzing sound is acc to BG related to that the membrane may loose tension during freight, and is not so common acc to BG.
The resonance is not, as I understand, related to the glue of the magnets. The information I got is that it may happen during freight that the membrane loose tensioning. Not very common acc to BG.
The investigation of the units is ongoing. More information follow.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.