Member
Joined 2003
Hi Steve,
Yes, I still have a pair of the P25REX/DD. Extremely flat FR for a 10"...like an oversized P13-WH-00. No project in mind, so I will sell them...pnwright3 at yahoo dott com.
Paul
Yes, I still have a pair of the P25REX/DD. Extremely flat FR for a 10"...like an oversized P13-WH-00. No project in mind, so I will sell them...pnwright3 at yahoo dott com.
Paul
Radian 850 vs. 950
Hi all,
just felt like adding a bit to this discussion, even though some of the posts referred to are from a while back...
Quote post #210 from Lynn Olson:
I asked specifically about the 950-PB (4" diaphragm & neo) vs the 850-PB (3" diaphragm & ceramic) and the implied much lower distortion for the 950-PB mentioned on the web-page, but Mike said the 950-PB is only about 2.5 to 3 dB lower than the 850-PB - and both are many DB lower than the competition from JBL and TAD. The larger diaphragm is why the 950-PB has a somewhat lumpier extreme HF compared to the smoothness of the 850-PB.
The 850 employs a 3 concentric ring phaseplug which limits the top end response somewhat with the chosen diaphragm size. It is a very good product and easily beats most, if not all the competition when it comes to overall performance and musicality in this market price segment.
The 950 is quite a different animal all together and was freshly developed from 'the ground up' and among other unique features, employs a novel Radian 5 ring/slit Bob Smith correct phaseplug with linear expansion rate resulting in something going/like 20dB's less distortion in comparison with other similar competitors products and HF extension beyond 19kHz! The indicated 'lumpiness' referred to in Lynn's post is mostly due to the chosen measurement method and choice of hornflare in the front of the driver, but true enough there is a little dip around 10kHz, due to the properties around the magnet gap and voice coil of the diaphragm. The 950 is however more consistent in HF performance than the 850 (I have independently measured and verified this...).
The reproduction resolution of the source material is also quite a lot better in the 950 due to the use of a quite substantial Neodymium magnet.
I would like to think it fair to class the Radian 950, as probably the best currently commonly commercially available comp. driver.
With best regards
'Dr' O aka a1greatdane aka Sven R. Olsen
Hi all,
just felt like adding a bit to this discussion, even though some of the posts referred to are from a while back...
Quote post #210 from Lynn Olson:
I asked specifically about the 950-PB (4" diaphragm & neo) vs the 850-PB (3" diaphragm & ceramic) and the implied much lower distortion for the 950-PB mentioned on the web-page, but Mike said the 950-PB is only about 2.5 to 3 dB lower than the 850-PB - and both are many DB lower than the competition from JBL and TAD. The larger diaphragm is why the 950-PB has a somewhat lumpier extreme HF compared to the smoothness of the 850-PB.
The 850 employs a 3 concentric ring phaseplug which limits the top end response somewhat with the chosen diaphragm size. It is a very good product and easily beats most, if not all the competition when it comes to overall performance and musicality in this market price segment.
The 950 is quite a different animal all together and was freshly developed from 'the ground up' and among other unique features, employs a novel Radian 5 ring/slit Bob Smith correct phaseplug with linear expansion rate resulting in something going/like 20dB's less distortion in comparison with other similar competitors products and HF extension beyond 19kHz! The indicated 'lumpiness' referred to in Lynn's post is mostly due to the chosen measurement method and choice of hornflare in the front of the driver, but true enough there is a little dip around 10kHz, due to the properties around the magnet gap and voice coil of the diaphragm. The 950 is however more consistent in HF performance than the 850 (I have independently measured and verified this...).
The reproduction resolution of the source material is also quite a lot better in the 950 due to the use of a quite substantial Neodymium magnet.
I would like to think it fair to class the Radian 950, as probably the best currently commonly commercially available comp. driver.
With best regards
'Dr' O aka a1greatdane aka Sven R. Olsen
Member
Joined 2003
Hi Sven,
I was never able to obtain distortion plots from Radian, and their published FR graphs seem overly smoothed. Would you mind posting your personal measurements of any of the Radian drivers?
I've already purchased different compression drivers...but that doesn't mean I won't try Radian too.
Thanks,
Paul
I was never able to obtain distortion plots from Radian, and their published FR graphs seem overly smoothed. Would you mind posting your personal measurements of any of the Radian drivers?
I've already purchased different compression drivers...but that doesn't mean I won't try Radian too.
Thanks,
Paul
Paul W said:
Jean-Michel had posted somewhere (don't remember), a comparison pdf showing several drivers on the same horn with similar correction filters.
In the group were DE250, 4552Nd, 380M, N681, and the (radian) 475PB.
Objectively the Radian was probably the 2nd worst driver with respect to overall linearity. Between 5-9 kHz there was a 3-4 db "trough" in the response. On the other hand between 1.8 and 5 kHz it was probably within +/-1 db.
Non-linear distortion was overall the worst of the group, though rather decent from 1.4 kHz up. The 4552Nd had by far the best distortion, though the DE250 was a close runner-up.
Linear decay wasn't bad for the driver. Even the first mode break-up at around 10-11 kHz was fairly benign. The Horn they were using effected a measure of delay all-along the lower end response as expected, but also a minor "ridge" from about 6-4 kHz down in freq. depending on the driver. Most notably the 4552Nd had the *least* reaction to this, but I'd say the Radian was a close second in this respect.
IMO this suggests that you shouldn't expect as much from the Radian's measured performance as you have been getting from the BMS drivers.
On the other hand what I've gathered from the subjective response of others is that Radian's typically sound better than other drivers - especially the BMS drivers, despite having poorer overall measured performance.
Oh well. 🙁
(..it is nice to see another subjective confirmation on the Radian 950 that I suggested to Lynn (..near the start of the Beyond Ariel thread).) 🙂
From analyzing that pdf.. something filtered into that vacant space in my skull. 
The fs (fb actually), is extraordinarily low for the sd.
My thinking is that this in combination with the compliant surround is the primary factor for the perceived better sound - specifically better imaging and depth.
i.e. larger rear chamber with less compression on that "side" of the diaphragm ='s better sound.
This guess could probably be tested fairly easily.
I don't think it would make a big difference for the BMS drivers because of their ring-radiator design (where the surround is the diaphragm and compliance is fairly "fixed"), but I could be wrong.
I'd also bet that the amount, type, and placement of any acoustical absorbing material in this chamber will effect this quality significantly, or at least I've found this to be the case with other drivers.
Anyway, just a thought on why the Radian's might be getting a better "billing". 😉
The fs (fb actually), is extraordinarily low for the sd.
My thinking is that this in combination with the compliant surround is the primary factor for the perceived better sound - specifically better imaging and depth.
i.e. larger rear chamber with less compression on that "side" of the diaphragm ='s better sound.
This guess could probably be tested fairly easily.
I don't think it would make a big difference for the BMS drivers because of their ring-radiator design (where the surround is the diaphragm and compliance is fairly "fixed"), but I could be wrong.
I'd also bet that the amount, type, and placement of any acoustical absorbing material in this chamber will effect this quality significantly, or at least I've found this to be the case with other drivers.
Anyway, just a thought on why the Radian's might be getting a better "billing". 😉
Member
Joined 2003
Hi Scott,
You think you have a vacant spot! I'm having a senior moment and don't even know which pdf you are referring to???
You think you have a vacant spot! I'm having a senior moment and don't even know which pdf you are referring to???
Paul W said:Hi Scott,
You think you have a vacant spot! I'm having a senior moment and don't even know which pdf you are referring to???
😀
I tried looking for it before and didn't manage to find it..
I'll search a bit more. 😉
Ah, success! (..it's a good think I didn't remove the title of the pdf when I downloaded it.)
http://pagesperso-orange.fr/francis.audio2/Comparaison_1pouce.pdf
Thanks for sharing😀
Looks like the DE250 is the champion (to me). No wonder it keeps obtaining excellent reputations.
Looks like the DE250 is the champion (to me). No wonder it keeps obtaining excellent reputations.
Very interesting.
However, I have never seen worse spelling in my life!
His English was worse than mine!
😀
Doug
However, I have never seen worse spelling in my life!
His English was worse than mine!
😀
Doug
CLS said:
Your welcome! (..though the real thanks should go to the author.. in fact I'll do that now: Thank you Par Francis Brooke!) 🙂
If you are looking for an extended bandwidth then I'd agree, just from these measurements the DE250 looks like a winner. Limit the bandwidth considerably, use a more appropriate compensation filter, and you might consider the BMS driver the winner - especially if you were to extend the sp-level on the time decay plots.
Radian vs. other Compression Drivers
Hallo Paul W,
interesting comparison of various CD drivers. I find it all a bit 'able and pears' though, but take it is with sound impressions in mind mostly?
We have here some quite wildly different topologies, concepts and material choices. There's plastic and Titanium diaphragms and so forth.
I do however agree that the standart Radian 475 might be the best offering from this vendor, being quite efficient at what it does. Not to mention that nice diaphragm construction of theirs. All the Radian 1" exit drivers employs a to my humble knowledge novel phaseplug with a centre hole and 2 concentric slits. Having said that - I can't remember if that has been invoked on the latest TAD 1" - 2002?
Anyway this is not very textbook, besides what arguments about 'back pressure' others might like to bring forward.
I have as another solution, successfully modified Radian 475's to almost correct 3 concentric slits and the difference in performance is quite astonishing. How about extended bandwidth to say something going towards 27kHz? And absolutely flat response after the HF mass break point? Sensitivity in the upper octaves also improved quite considerably and if my memory does not fail my completely, to something like 104-5dB/W/m. I shall have 'a dig and exploration and c if I can manage to find some curves.
By the by re. curves: Has anybody got a LEAP V disk they could forward as a downloadable entity? I have got the key, but have lost the disk while moving to London.
But in the end of the the day (to use a nice old cliché), who listens to curves?
Best regards
a1greatdane
Hallo Paul W,
interesting comparison of various CD drivers. I find it all a bit 'able and pears' though, but take it is with sound impressions in mind mostly?
We have here some quite wildly different topologies, concepts and material choices. There's plastic and Titanium diaphragms and so forth.
I do however agree that the standart Radian 475 might be the best offering from this vendor, being quite efficient at what it does. Not to mention that nice diaphragm construction of theirs. All the Radian 1" exit drivers employs a to my humble knowledge novel phaseplug with a centre hole and 2 concentric slits. Having said that - I can't remember if that has been invoked on the latest TAD 1" - 2002?
Anyway this is not very textbook, besides what arguments about 'back pressure' others might like to bring forward.
I have as another solution, successfully modified Radian 475's to almost correct 3 concentric slits and the difference in performance is quite astonishing. How about extended bandwidth to say something going towards 27kHz? And absolutely flat response after the HF mass break point? Sensitivity in the upper octaves also improved quite considerably and if my memory does not fail my completely, to something like 104-5dB/W/m. I shall have 'a dig and exploration and c if I can manage to find some curves.
By the by re. curves: Has anybody got a LEAP V disk they could forward as a downloadable entity? I have got the key, but have lost the disk while moving to London.
But in the end of the the day (to use a nice old cliché), who listens to curves?
Best regards
a1greatdane
Re: Radian vs. other Compression Drivers
..and pictures please! 😀
(..we need to have more loudspeaker driver modification threads on this forum.)
a1greatdane said:
..and pictures please! 😀
(..we need to have more loudspeaker driver modification threads on this forum.)
Member
Joined 2003
Yes! Pictures "before and after" with pictures of the modification process would be much appreciated!
Re: Radian vs. other Compression Drivers
I'm very interested in your modification of the Radian 475 - that's far better performance than the standard unit. Performance on a modern low-diffraction horn or waveguide should be exceptional with a driver that good.
a1greatdane said:
I'm very interested in your modification of the Radian 475 - that's far better performance than the standard unit. Performance on a modern low-diffraction horn or waveguide should be exceptional with a driver that good.
ScottG said:From analyzing that pdf.. something filtered into that vacant space in my skull.
The fs (fb actually), is extraordinarily low for the sd.
My thinking is that this in combination with the compliant surround is the primary factor for the perceived better sound - specifically better imaging and depth.
i.e. larger rear chamber with less compression on that "side" of the diaphragm ='s better sound.
This guess could probably be tested fairly easily.
I don't think it would make a big difference for the BMS drivers because of their ring-radiator design (where the surround is the diaphragm and compliance is fairly "fixed"), but I could be wrong.
I'd also bet that the amount, type, and placement of any acoustical absorbing material in this chamber will effect this quality significantly, or at least I've found this to be the case with other drivers.
Anyway, just a thought on why the Radian's might be getting a better "billing". 😉
While doing some searching on a different subject I came across this from Jean-Michel:
"..That's probably due to the thrill in my spine when I listen to such good drivers as Onken, Goto, Western Electric... I never experienced such with cone drivers mounted on horns, even if some of them were very good sounding compared to 90% of the commercial stuff
The resonance frequency (mounted on the horn it may differ than the one mesured on planar wave tube) plays a role for sure in the sound. Generally I try to avoid the resonance frequency to be in the middle of the useful bandwith of the horn
The Goto and the WE possess low resonance frequency, may be that's one of the reasons why I liked them so much.
Best regards from Paris, France
Jean-Michel Le Cléac'h"
Interesting. 😉
Radian 475 curves
Hi Lynn,
I know I have some curves of a modified Radian 475 somewhere, but have not managed to find them so far. I have on the other hand recently modified some 465's and will post some curves when I get around to getting them measured.
Kind regards
a1greatdane
Hi Lynn,
I know I have some curves of a modified Radian 475 somewhere, but have not managed to find them so far. I have on the other hand recently modified some 465's and will post some curves when I get around to getting them measured.
Kind regards
a1greatdane
Hi ScottG,
Does that mean, we may probably get a better sound (in a particular horn and frequency band) by enlarging the back chamber ? -- Say, in a mid horn, for the sake of this topic "Large midrange... "
If we manage to loosen the suspension of a given driver (higher compliance), with the same motor and cone mass, the fs drops and the Qts also drops. A lower Q driver drivers the horn better, so it makes sense.
A large back chamber.... hmm.... so how about a very very big one -- just leave it open? I've tried 'open back' on my Oris horn -- no back chamber. I did like the sound better than the one with chamber -- sounded more open and free, less coloration of resonance. And so did Mr. Bruce Edgar suggest in his article of Tractrix midhorn.
So how about removing the back chamber (rear cover) of a compression driver? I haven't seen this.
CLS🙂
Does that mean, we may probably get a better sound (in a particular horn and frequency band) by enlarging the back chamber ? -- Say, in a mid horn, for the sake of this topic "Large midrange... "
If we manage to loosen the suspension of a given driver (higher compliance), with the same motor and cone mass, the fs drops and the Qts also drops. A lower Q driver drivers the horn better, so it makes sense.
A large back chamber.... hmm.... so how about a very very big one -- just leave it open? I've tried 'open back' on my Oris horn -- no back chamber. I did like the sound better than the one with chamber -- sounded more open and free, less coloration of resonance. And so did Mr. Bruce Edgar suggest in his article of Tractrix midhorn.
So how about removing the back chamber (rear cover) of a compression driver? I haven't seen this.
CLS🙂
Member
Joined 2003
The consumer versions of the JBL Be drivers also implement a larger rear chamber than the equivalent pro versions.
Depending on specific compression driver construction, it may be possible to space the rear chamber/cup further back with circular rings cut from aluminum, masonite, MDF, etc.
The system I'm working on now includes Infinite Baffle midbass to go along with IB subs...bigger boxes can be better boxes!
Depending on specific compression driver construction, it may be possible to space the rear chamber/cup further back with circular rings cut from aluminum, masonite, MDF, etc.
The system I'm working on now includes Infinite Baffle midbass to go along with IB subs...bigger boxes can be better boxes!
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