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Old 10th March 2010, 11:53 AM   #21
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I tested the Visaton B200 and also the Seas Exotic 4 Ohm.
The Visaton has a lot of distortion in the treble, the SEAS has a wither cone that creates problems. The SEAS was designed by Björn Börja the senior engineer at SEAS.
Dr. Kurt Müller is a supplier of membranes from Germany with subsidary in England.
We can make a wideband that has more extention in the treble but radiation pattern is a problem like LineArray said. We can make Neodymium versions that are not so expensive then Alnico versions.
Widebanders have not the best resolution in the higher treble ether.
They have to work in the breakup region and have a issue with moving mass.
That is the reason i will use a ribbon tweeter.
The other driver has been measured with other equipment by another person so this measurements are not directly comparable.
When i get the finished driver ( without peak) i will do the measurements with my equipment again.
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Old 10th March 2010, 04:12 PM   #22
graaf is offline graaf  Poland
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Quote:
Originally Posted by Joachim Gerhard View Post
We can make a wideband that has more extention in the treble but radiation pattern is a problem like LineArray said.
that depends
of course You are right in case of conventional front firing speakers BUT my idea is something different, something aptly called "ceiling flooder" and which is a kind of Sonab V1 turned to serious speaker project
essentially a short speaker with 8 inches full ranger on top firing up towards the ceiling, for such speaker I propose Beverigde or near-corner placement

my idea behind this project is of high fidelity that is available for any interested music lover, that is just like any other "room service", genuine a Hartley's ideal, not jewel-like boutique gadgetry, not big ugly technical things almost in the middle of the room, but something that is quite inobtrusive, that would work properly in a typical living room, that takes minimal space close to walls and requires no decor-destroying "acoustical adaptations"

in case of such "ceiling flooders" high directivity or even frequency dependent "discontinuities in angular dispersion" are not of critical importance because:
1) the diffuse sound field they create in a typical room is dominated by reflections from the "flooded" ceiling which is the largest reflective surface in the room (thus contributing mostly to the created sound field) and
2) those reflections are quite uniform spectrally because the speakers typically are "flashing" at the ceiling from considerable distance of 2.5 m or more (speaker drivers are just 20 cm above the floor) so not at particularly acute angles where one can find those "frequency dependent discontinuities"

what I need is good 8 inches full ranger, without shouts and able to produce real bass in a small "acoustic suspension" with help of "boundary room augmentation", I see it as continuation of Villchur-Allison line of thinking

Problem is that I cannot see any such driver on the market and therefore I am so interested in this thread

Quote:
Originally Posted by Joachim Gerhard View Post
We can make Neodymium versions that are not so expensive then Alnico versions.
neodymium version would be great

Quote:
Originally Posted by Joachim Gerhard View Post
Widebanders have not the best resolution in the higher treble ether.
They have to work in the breakup region and have a issue with moving mass.
That is the reason i will use a ribbon tweeter.
well, certainly BUT there are reasons for full range afficionados' preference for full range ie. one way and for that such thing is considered an ideal
of course with real world speakers it is all about tradeoffs

but add tweeter and we are in the multi way territory, something is gained but something is lost as well

for full range afficionados that what is lost is more important but it is of course a matter for another discussion

and if we decide to go multi way then why use old fashioned full range wideband paper drivers at all? and why cross the tweeter so high?
at 6 kHz ribbon tweeter would not help with beaming and "discontinuities in angular dispersion" or with breakup problems because they start two octaves lower, it can only add some otherwise (subjectively for some audiophiles) missing highs, like in case of the above linked Hotei speaker

best regards!
graaf
ps.
on the attached illustration is Sonab V1, it utilized whizzered 8 incher from Philips
Attached Images
File Type: jpg sonab V1.JPG (27.1 KB, 1350 views)
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Last edited by graaf; 10th March 2010 at 04:23 PM.
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Old 14th March 2010, 01:40 PM   #23
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Here are some photos of the wideband driver in a test baffle.
Attached Images
File Type: jpg Wideband Testbaffle.jpg (71.8 KB, 1334 views)
File Type: jpg Wideband Back.jpg (78.4 KB, 1302 views)
File Type: jpg Wideband 1.jpg (40.3 KB, 1283 views)
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Old 14th March 2010, 08:15 PM   #24
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Asymmetric mounting makes my heart open wide !

Real "cultic" look that driver, beautiful enough to
make some photos of the driver solely ....

Maybe on smoke glass shelf or a black reflecting background

From cultic look alone competitive with other cultic drivers for sure,
and looks well manufactured, large spider venting ...

What kind of material is the surround ?

Pictures seem a little unterexposed.
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Old 14th March 2010, 08:32 PM   #25
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i will do a better photo tomorrow.
The surround is also from paper, thined out so that light shines through and coated from the back.
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Old 15th March 2010, 10:58 AM   #26
graaf is offline graaf  Poland
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nice!
it looks a bit like a combination of a Supravox cone and Seas Exotic's "red" magnet

BTW - as You had opportunity to know Mr Rehde can You tell me what was the supply source of His drivers? Was it also Audax?
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Last edited by graaf; 15th March 2010 at 11:06 AM.
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Old 15th March 2010, 11:35 AM   #27
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Rehde was the Audax designer for may years. The membranes where made for him by Audax.
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Old 15th March 2010, 12:28 PM   #28
graaf is offline graaf  Poland
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Quote:
Originally Posted by Joachim Gerhard View Post
Rehde was the Audax designer for may years. The membranes where made for him by Audax.
Can it explain the end of the Rehdeko?
I mean Harman started liquidation of Audax speaker division in 1999 and in 2001 Mr Rehde closed His business IIRC.
Joel Rehde suggested that it was due to lack of supply parts of adequate quality and that in the end it was closing of the business that was the cause of death of His father.

in a sense corporate killer Harman killed one great artist
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Old 28th March 2010, 11:48 PM   #29
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I know a lot about Rehde but i do not like to discuss this here. He certainly had a very interesting and fullfilling life.
...........

Some days ago i got the fitting tweeters for my "Extended Midrange Drivers" as i will call them. They can be made to go to 12kHz but higher then that you need a wizzer cone and the designer whanted to avoid that. Wizzers cause a lot of trouble in the frequency and time domain so i decided on an "Overtone" tweeter that comes in slowly over 7kHz.
The tweeter i choose is a ribbon with horn made by Fountek. In Germany they are sold under the Audaphon and Dynavox brand with wildly varying price and image.
i do not care about that and the tweeter is actually very good and has the ideal radiation pattern and sensitivity. I made a simple and fast 6dB crossover that worked surprising well also in the time domain. I will show measurements later when the tread develops because i found that publishing preliminary data here causes a lot of confusion. People take that simply much to serious and the driver is still under development although the path where to go is cast.
My setup now is the JG Self Preamp with two cables, one goes to the active subwoofer and one goes to my main amp where i filter the MPL with a cap in series with the input impedance of the amp. It´s a kind of semi active setup that i use ones in a while since the early 80th. Actually i find it more transparent souding then most fully active solutions i tried. Lots of extra electronics and cables must not automatically guarantee better sound.
Bargainers will love the 0.6mm twisted solid core cables. Yes, i think for a dipole with 95 - 96dB sensitivity and 8 Ohm it is adequate when it is not too long.
Nicer cabinets will be build and i also build two different dipole woofers that will complement the MPL better then the closed monopole so this setup is really an early bird. Sounds very nice though. Lots of resolution and dynamics that are simply swallowed in spaekers with more damping.
Attached Images
File Type: jpg MPL Prototype Front.jpg (72.2 KB, 1150 views)
File Type: jpg MPL from back.jpg (70.7 KB, 500 views)
File Type: jpg Two stereo cables from Pre.jpg (79.8 KB, 482 views)
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Old 28th March 2010, 11:50 PM   #30
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Here is the linefilter with my favourite Röderstein caps and the subwoofer.
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File Type: jpg Line Filter.jpg (57.9 KB, 444 views)
File Type: jpg Subwoofer.jpg (72.0 KB, 327 views)
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