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Old 9th March 2010, 11:49 PM   #11
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Quote:
Originally Posted by graaf View Post
50 years have passed, we presumably have all this hi-tech (from new materials to new measurements) unavailable to Hartley and His contemporaries and yet we can't fix those same old problems?

this is so disappointing
I couldn't agree more. And I don't understand this mystery any more than you do. I was simply amazed at how awful the expensive and inexpensive fullrange drivers sounded (Lowther, AER, Fostex, etc). I have no other word for it. Amazed. If a cone can't be driven above 90db without eardrum killing distortion around 1-4khz what good is it? No good at all!

Since I don't like the vague sound of contemporary multiway drivers and designs, I've decided there are only 2 possible avenues from here: DIY cone treatments to make the FR behave or buy a set of the large Bohlender Graebener units; both of which I plan to do.
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Old 10th March 2010, 12:31 AM   #12
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Default Good Widebands are posible

We can make a wideband that is flat from 60Hz to 10kHz + - 2dB with 95dB efficiency at 8 Ohm.
Distortion in that driver is very low and linear over the whole response.
See some measurements i did with multitone.
The driver has a dynamic range of 70dB. Marker 1 and 2 show hum from the poweramp.
The best old drivers i measured had distortion much higher and not more then 60dB dynamic range. I also did an inverserse FFT from the hidden spectrum.
Noise in that driver is only 250nP. See again the 50 Hz component that does not come from the driver but is hum from the measurement amp.
I used an Alesis professional amp for this.
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Old 10th March 2010, 12:39 AM   #13
wahab is offline wahab  Algeria
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Old 10th March 2010, 12:42 AM   #14
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Here you can listen to the invers FFT.
Attached Files
File Type: zip MPL Wideband Distortion Residuum.wav.zip (216.0 KB, 69 views)
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Old 10th March 2010, 12:44 AM   #15
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Hello Wahab !
we use membranes from France from the old Audax factory.
We tried a lot but that was by far the best.
We also tried Dr.Müller and far east.
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Old 10th March 2010, 08:38 AM   #16
graaf is offline graaf  Poland
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Quote:
Originally Posted by Joachim Gerhard View Post
Here is another version of the wideband. Are you more happy with that graaf ?
it certainly looks nicer

but it is hard to compare those two graphs (the previously posted and the second) and to draw any conclusions because of different scales, averaging etc. although I can see general similarity of both FR curves

Quote:
Originally Posted by Joachim Gerhard View Post
We can make a wideband that is flat from 60Hz to 10kHz + - 2dB with 95dB efficiency at 8 Ohm.
+/- 2 dB certainly is impressive

in fact there are widebanders for OB, pretty flat and with low distortions (according to manufacturer's proclamations), more or less expensive, like PHY-HP or Visaton B200

there is bigger problem with fullrangers
I am looking for something with a decent headroom (which means 8 inches at least), free from any shouts (those "eardrum killing distortion around 1-4khz" as put by InclinedPlane few posts above) that would work nicely without a tweeter and be capable of providing at least some real, non-resonant bass, not necessarily down to 20-ies - some 40-ies in room would suffice
but without horns or any other refrigerator-sized cabinets, rather in a moderate-sized acoustic suspension
oh well ported could be also ok provided it is small like Rehdeko 115, no bigger

I do like OBs but I think that they are just impractical for most music lovers, it' s mostly question of their size and placement requirements
and multi-way OBs are complicated from DIY perspective, very difficult to tune all the elements in

I think that it is not coincidence that AR-1 - the first compact bookshelf speaker - was such an epoch-making product

Is there any chance for a fullranger without shouts that could work nicely in a compact box? and that would not cost a small fortune? Alnico not really necessary

currently I am tweaking Fostex FE206E, nice affordable driver with great tweaking potential, a widely known fact for sure , but it is strictly a tweaker's speaker, it is just horrible out of the box and not really suited to the use in a compact enclosure
FE206E can be succesfully tweaked at home (using ideas similar to Hegeman's or Rehde's) but it would be great to have simply a driver with Fostex's problems fixed by means of all professional design instruments, measurements, standardization and so on
all measured and clearly audible, unlike in case of various "phase plugs" or "EnABLs" etc. the effects of which can hardly be measured not to mention to be consistently audible or at least rationally explained...

I had a dream ...

best regards!
graaf
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Last edited by graaf; 10th March 2010 at 08:51 AM.
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Old 10th March 2010, 08:50 AM   #17
graaf is offline graaf  Poland
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Quote:
Originally Posted by InclinedPlane View Post
Since I don't like the vague sound of contemporary multiway drivers and designs, I've decided there are only 2 possible avenues from here: DIY cone treatments to make the FR behave or buy a set of the large Bohlender Graebener units; both of which I plan to do.
but BG, even those largest, are just very big midtweeters - manufacturer's "network recommendations": 150Hz, minimum 12 dB/oct. electrical minimum"

You end up with multi-way speaker anyway

therefore "DIY cone treatments to make the FR behave" is the only way IMO
and more precisely - "8 inches paper cone treatments" as You already know

best,
graaf
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Old 10th March 2010, 08:56 AM   #18
wahab is offline wahab  Algeria
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Quote:
Originally Posted by Joachim Gerhard View Post
Hello Wahab !
we use membranes from France from the old Audax factory.
We tried a lot but that was by far the best.
We also tried Dr.Müller and far east.
Hi, joachim
Thank you for the infos about your speakers of choice..
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Old 10th March 2010, 09:08 AM   #19
graaf is offline graaf  Poland
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who is Dr. Müller? It's the designer of Seas Exotic F8 cone? Do I remember correctly?

anyway, F8 also has the same nasty 3 kHz peak for 900 Euro each
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Old 10th March 2010, 10:51 AM   #20
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To me one of the drawbacks of conventional cone
fullrangers and widebanders is, that with enough
tweaking they can be made reasonably flat on axis,
but this cannot go together with a flat power response.

Angular dispersion narrows with increasing frequency
reasonably continouus in the best case.
In the worst case there are several discontinuities in
angular dispersion dependent from frequency,
which will make the result very room dependent -
and prone to "sweet spot listening".

I'll give conventional full/wide range technology about a
decade to survive, at least in the high quality segment.

Arrays of integratively manufactured micro transducers,
developing DML and related designs will take over.
I do not say this to "downplay" the good results
presented here, but the more tweaking is done,
the more the limitations get clear also.

The popularity of vintage drivers, which are in many
cases competitive to recent products, is an indicator for
that too.

Just my opinion.
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Last edited by LineArray; 10th March 2010 at 10:56 AM.
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