Yeah the 21-inchers are F@$&ing great.... 
I think some of the trick is to place the dipole peak at or slightly below XO to maximize the output up to XO, and still be in the Constant Directivity frequency range of the dipole (which is below dipole peak). That means very large baffles if you intend to XO at 200 Hz. I think it can be done with smaller drivers than 21" of course, but the baffle still needs to be large.
I think some of the trick is to place the dipole peak at or slightly below XO to maximize the output up to XO, and still be in the Constant Directivity frequency range of the dipole (which is below dipole peak). That means very large baffles if you intend to XO at 200 Hz. I think it can be done with smaller drivers than 21" of course, but the baffle still needs to be large.
Dipole. There is a foam pad at the rear, but frequency response is virtually the same front/rear.
See graph below. The range marked green is what I consider the "best" frequency range to operate a dipole, that is from the dipole peak and down to approx 12 dB roll-off.
As you see, for optimal performance to 200 Hz, the baffle needs to be 1,5 meter wide. Even if you use an H-baffle to increase the effective path length, its going to be a very big baffle.
As you see, for optimal performance to 200 Hz, the baffle needs to be 1,5 meter wide. Even if you use an H-baffle to increase the effective path length, its going to be a very big baffle.
An externally hosted image should be here but it was not working when we last tested it.
Not much for nude. The magnet on cone drivers means asymmetrical front and rear response above the dipole peak and none of the open back domes have sufficient Vd for much reach below their dipole peak. Flame and plasma tweeters have the same trouble, as do AMTs and true ribbons. That leaves electrostats and magnetostats where it's pretty much either DIY or the various BG RDs, Neo8, or Neo10. If you can live with the narrowing horizontal directivity and need for a supertweeter the Neo10 is the price/performance leader for a single off the shelf driver. Neo8 line arrays are a bit cheaper per foot than the RDs and might sound a bit better as their self resonance is at 12kHz instead of 5. I'm not aware of anyone who's tried the two side by side though.
An open back dome in a dipole horn would be interesting but I think at that point one might as well use the Neo3 for its lower moving mass.
Also remember that so-called "fullrange" cone drivers usually have a whizzer cone, where the mechanical crossover frequency is around 3 kHz (??). That means that the driver is monopole in a very big part of the frequency range.
How low can you run Neo8 or Neo10 in dipole, either nude or with baffle? With closed back there is not much output below 1 kHz ...
How low can you run Neo8 or Neo10 in dipole, either nude or with baffle? With closed back there is not much output below 1 kHz ...
the neo10 is dipole / open backed and can be run quite low but would need a tweeter .
here is a project using two neo10 :
Raal 140, Neo10, AE Dipole 15 in the works
efficiency and other specs of the neo10 is "better"
The Neo10 is the next step in the line of BG's planar ribbon drivers. The design goals include higher sensitivity, lower distortion, a lower usable cut off frequency, and higher power handling than previous offerings. This provides a solution to an important system goal – uncompromised reproduction of the human vocal range.
An additional benefit of the extended bandwidth is improved integration with a dynamic woofer. Seamless integration has been a challenge in practice historically and this is much easier to accomplish at 150-250 Hz than at an octave higher.
Construction Details
While the Neo10 has design principles similar to the Neo8, its construction has significant differences. The goal of extended low frequency reproduction dictated the use of a larger magnetic gap for higher excursion. Large magnets were used to further increase magnetic flux density in the gap.
here is a project using two neo10 :
Raal 140, Neo10, AE Dipole 15 in the works
efficiency and other specs of the neo10 is "better"
The Neo10 is the next step in the line of BG's planar ribbon drivers. The design goals include higher sensitivity, lower distortion, a lower usable cut off frequency, and higher power handling than previous offerings. This provides a solution to an important system goal – uncompromised reproduction of the human vocal range.
An additional benefit of the extended bandwidth is improved integration with a dynamic woofer. Seamless integration has been a challenge in practice historically and this is much easier to accomplish at 150-250 Hz than at an octave higher.
Construction Details
While the Neo10 has design principles similar to the Neo8, its construction has significant differences. The goal of extended low frequency reproduction dictated the use of a larger magnetic gap for higher excursion. Large magnets were used to further increase magnetic flux density in the gap.
My nude Neo10 data is here. Neo8 data is collected in this thread. The Neo8-S is interesting as it shares the Neo10's pleated diaphragm and hence should have a good bit more low end reach than the 8. Pricier than the RDs and I haven't seen characterization data for it, though it's been a few months since I checked.
Hello Stig,
in a Dipol a single Neo 10 can play down to about 300 Hz. Like for example in this construction :
http://www.audax-speaker.de/index.php?module=shop_articles&index[shop_articles][action]=details&index[shop_articles][category==2&index[shop_articles][data][shop_articles_id]=83]%[/category][category=
In a multiple setting or with limited SPL imo the Neo 10 might be used down to even a bit below 200 Hz like the BG 75. In an infinite baffle K2 and K3 are round about 0,4% @ 100 Hz, at 90 ond more dB from 400 Hz up.( but keep in mind that the sensitivity in this measurement is down 8 dB @ 100 Hz )
The test of the construction mentioned above, including the measurement of the Neo 10 is available here: ( scroll to middle of site ) http://www.audax-speaker.de/index.php?module=downloads&index[downloads][action]=overview&index[downloads][first]=20&index[downloads][order]=downloads_position%20ASC
I think the use of a normal Neo 8 makes sense down to 700-800 Hz. After that point the distortion rises significantly. But many of the normal ones seam to have a problem with variations in the production quality.
Proraum is ( exclusively ? )selling a version of the Neo 8 with bigger magnets, an impedance of 8 Ohm and a claim of more X-max due to a kind of corrugation added. But I haven´t seen any distortion measurements of this model so far.
Neo 8 S:
http://www.audax-speaker.de/index.php?module=shop_articles&index[shop_articles][action]=details&index[shop_articles][category==11&index[shop_articles][data][shop_articles_id]=105]%[/category][category=
G F]%[/category]]%[/category]
in a Dipol a single Neo 10 can play down to about 300 Hz. Like for example in this construction :
http://www.audax-speaker.de/index.php?module=shop_articles&index[shop_articles][action]=details&index[shop_articles][category==2&index[shop_articles][data][shop_articles_id]=83]%[/category][category=
In a multiple setting or with limited SPL imo the Neo 10 might be used down to even a bit below 200 Hz like the BG 75. In an infinite baffle K2 and K3 are round about 0,4% @ 100 Hz, at 90 ond more dB from 400 Hz up.( but keep in mind that the sensitivity in this measurement is down 8 dB @ 100 Hz )
The test of the construction mentioned above, including the measurement of the Neo 10 is available here: ( scroll to middle of site ) http://www.audax-speaker.de/index.php?module=downloads&index[downloads][action]=overview&index[downloads][first]=20&index[downloads][order]=downloads_position%20ASC
I think the use of a normal Neo 8 makes sense down to 700-800 Hz. After that point the distortion rises significantly. But many of the normal ones seam to have a problem with variations in the production quality.
Proraum is ( exclusively ? )selling a version of the Neo 8 with bigger magnets, an impedance of 8 Ohm and a claim of more X-max due to a kind of corrugation added. But I haven´t seen any distortion measurements of this model so far.
Neo 8 S:
http://www.audax-speaker.de/index.php?module=shop_articles&index[shop_articles][action]=details&index[shop_articles][category==11&index[shop_articles][data][shop_articles_id]=105]%[/category][category=
G F]%[/category]]%[/category]
Last edited:
The Norwegian speaker manufacturopr Forsman uses the NEO 10 in his new folded dipol speaker!
Forsman AS
They are reported to sound very good.....
br
OMF
Forsman AS
They are reported to sound very good.....
br
OMF
I've never actually seen (or heard) the Neo10... I hope it will be generally available soon. From the measurements done by Klang&Ton it looks like a very good midrange, but its sadly not a wideband driver, so it needs a mid-woofer and tweeter. It will be a 3-way.
What I love with the RD-75 is that you can avoid XO points in the midrange and treble. Crossover at 150-200 Hz is less critical, and it makes it possible to build a dedicated subwoofer system that you can locate away from the main speakers, and even use distributed subwoofers.
And I absolutely love the sound of the RD-75 ..... its in a class of its own.
What I love with the RD-75 is that you can avoid XO points in the midrange and treble. Crossover at 150-200 Hz is less critical, and it makes it possible to build a dedicated subwoofer system that you can locate away from the main speakers, and even use distributed subwoofers.
And I absolutely love the sound of the RD-75 ..... its in a class of its own.
Not nude but scantily dressed neo10 & neo3 with dipole15, still some work to do & yes 3way,
http://www.diyaudio.com/forums/multi-way/175072-ob-project-design-started-help-requested-27.html
http://www.diyaudio.com/forums/multi-way/175072-ob-project-design-started-help-requested-27.html
Hallo,
even though I haven´t heard the RD 75 I am about to believe what you say Stig. There might really be no real competitor to the big B&G´s out there ... .
I haven´t seen any so far; if I don´t take the electrostatic ones in to the view.
How do estimate the SD? My rough calculation leads me to something about 450-550 cm². Has any one ever seen a RD driver without the housing? It would be interesting to know how big the diaphragm actually is.
G F
even though I haven´t heard the RD 75 I am about to believe what you say Stig. There might really be no real competitor to the big B&G´s out there ... .
I haven´t seen any so far; if I don´t take the electrostatic ones in to the view.
How do estimate the SD? My rough calculation leads me to something about 450-550 cm². Has any one ever seen a RD driver without the housing? It would be interesting to know how big the diaphragm actually is.
G F
This is a very interesting development Stig!
I have personally liked the "full range" cdoncept - and my current Mangers do the job from about 400 Hz and upwards!
I do however have a few questions related to this recent development.....
1) How is the transition from Woofer to ribbon....?
2) What about the punch and impact - are the ribbons at the same level at the excels..?
3) What about warmth, body, bloom and all that stuff - I kind of have a prejudice that it will sound somewhat lean....?
Have you tried to cross over higher and fill in with some 6,5/8/10 inch drivers....?
Anyway - this is a fantastic result for my forever ongoing project.....With IB subwoofers and a single ribbon....WAF will skyrocket!
Thanks again for sharing your wisdom and efforts!
OMF
I have personally liked the "full range" cdoncept - and my current Mangers do the job from about 400 Hz and upwards!
I do however have a few questions related to this recent development.....
1) How is the transition from Woofer to ribbon....?
2) What about the punch and impact - are the ribbons at the same level at the excels..?
3) What about warmth, body, bloom and all that stuff - I kind of have a prejudice that it will sound somewhat lean....?
Have you tried to cross over higher and fill in with some 6,5/8/10 inch drivers....?
Anyway - this is a fantastic result for my forever ongoing project.....With IB subwoofers and a single ribbon....WAF will skyrocket!
Thanks again for sharing your wisdom and efforts!
OMF
Hi there buddy...
1. Transistion is seamless, impossible to hear the XO point in my setup. Your own idea with IB woofers placed far away might be difficult to integrate though....
2. Punch... impact. Depends on what you mean. Will it sound like a 15" paper woofer in a quarter-wave horn? No. Will it have realistic natural dynamics? Yes.
3. My old setup with cone drivers did sound "fatter", but that I dont miss at all. And no - the ribbon does not sound thin, lean or shrill once you get used to not having a lot of lower-midrange coloration..... actually I would like to tilt the response upwards! Currently I run a frequency response that is dead flat from 50 to 20 kHz, with a little boost down to 20 Hz (below 50 Hz).
I did try a line of 10" woofers, crossed over anywhere between 200 and 600 Hz. It did not work well, it sounded fat and slow compared to what my giant H-baffles can do up to 200 Hz, and what the ribbon can do down to 200 Hz.
This whole thing started with that actually:
1. Transistion is seamless, impossible to hear the XO point in my setup. Your own idea with IB woofers placed far away might be difficult to integrate though....
2. Punch... impact. Depends on what you mean. Will it sound like a 15" paper woofer in a quarter-wave horn? No. Will it have realistic natural dynamics? Yes.
3. My old setup with cone drivers did sound "fatter", but that I dont miss at all. And no - the ribbon does not sound thin, lean or shrill once you get used to not having a lot of lower-midrange coloration..... actually I would like to tilt the response upwards! Currently I run a frequency response that is dead flat from 50 to 20 kHz, with a little boost down to 20 Hz (below 50 Hz).
I did try a line of 10" woofers, crossed over anywhere between 200 and 600 Hz. It did not work well, it sounded fat and slow compared to what my giant H-baffles can do up to 200 Hz, and what the ribbon can do down to 200 Hz.
This whole thing started with that actually:
An externally hosted image should be here but it was not working when we last tested it.
I did a few tests yesterday and today, including some measurements.
1. I played "Dire Straits - Money for Nothing" at 95 dB average level in listening position. That's some 107-109 dB peak, which is pretty loud. 10 dB more than I usually play. Even at this level it was impossible to see any movement of the ribbon, but I could feel the sound with my hand if I held it in front of the ribbon. I wonder how loud people play when the actually see the ribbon moving.......
2. Off axis....
It's fairly well-behaved off-axis. No big peaks or dips. So far so good. However - the ribbon is a line-source only down to about 1 kHz. What happens when you move away in distance or move up and down the ribbon, is that the level starts to drop below 1 kHz. So - at some distance or when standing up, the speaker sounds brighter. The same happens with my H-baffle woofers as well, because they are directional and pointed to the listening position. All in all - my setup sounds a little brighter around the room that it does in the listening position. The old speakers were better in this respect since they were more or less point sources. I can easily fix this by having two EQ setups - one for the main listening position, and one for casual listening flat out on the sofa....
1. I played "Dire Straits - Money for Nothing" at 95 dB average level in listening position. That's some 107-109 dB peak, which is pretty loud. 10 dB more than I usually play. Even at this level it was impossible to see any movement of the ribbon, but I could feel the sound with my hand if I held it in front of the ribbon. I wonder how loud people play when the actually see the ribbon moving.......
2. Off axis....
It's fairly well-behaved off-axis. No big peaks or dips. So far so good. However - the ribbon is a line-source only down to about 1 kHz. What happens when you move away in distance or move up and down the ribbon, is that the level starts to drop below 1 kHz. So - at some distance or when standing up, the speaker sounds brighter. The same happens with my H-baffle woofers as well, because they are directional and pointed to the listening position. All in all - my setup sounds a little brighter around the room that it does in the listening position. The old speakers were better in this respect since they were more or less point sources. I can easily fix this by having two EQ setups - one for the main listening position, and one for casual listening flat out on the sofa....
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.