Tinitus, ...''wish I knew more about used material and build
quality''
Like I mentioned before, Michel Fertin can answer you questions
on Monday....Helps being able to talk with the designer.
As to compare with the Faital , Bayma or other drivers...difficult
without being able to hear all of them. As for the price...many
times it's worthed to pay a bit more and also get better sound
quality. But we must be sure that this is what we really get...
As to be a dedicated full range or a 3 way person (needing a
big woofer for the bass). Here, I've talked to many people;
most like big bass....others like the coherence of a full range,
no tweeter, no additional woofer , no xover .
I've just finished reading the book of M. Floyd E. Toole-
Sound reproduction loudspeakers and room.
Very informative book, I would say a must read for
everybody interested in audio. He surely goes along
with you in saying that you need dedicated bass woofers
equalized to your room to have proper bass.
A while back I sent a pair of LB12 to Peter Daniel for audition.
He had them for a month. He used them in his infinite baffle.
(low qts driver for open-baffle, not the best without some
king of compensation.They are better in cabinet.
He compared the sound of the
driver with and without a tweeter. We exchange e-mails
about the LB12. I can ask Peter if he would mind that
I post his comments....
quality''
Like I mentioned before, Michel Fertin can answer you questions
on Monday....Helps being able to talk with the designer.
As to compare with the Faital , Bayma or other drivers...difficult
without being able to hear all of them. As for the price...many
times it's worthed to pay a bit more and also get better sound
quality. But we must be sure that this is what we really get...
As to be a dedicated full range or a 3 way person (needing a
big woofer for the bass). Here, I've talked to many people;
most like big bass....others like the coherence of a full range,
no tweeter, no additional woofer , no xover .
I've just finished reading the book of M. Floyd E. Toole-
Sound reproduction loudspeakers and room.
Very informative book, I would say a must read for
everybody interested in audio. He surely goes along
with you in saying that you need dedicated bass woofers
equalized to your room to have proper bass.
A while back I sent a pair of LB12 to Peter Daniel for audition.
He had them for a month. He used them in his infinite baffle.
(low qts driver for open-baffle, not the best without some
king of compensation.They are better in cabinet.
He compared the sound of the
driver with and without a tweeter. We exchange e-mails
about the LB12. I can ask Peter if he would mind that
I post his comments....
lrntglls said:
Yeah thanks, would interesting...and now you are at it maybe some response and impedance curves please 😀
I have some partial info from Michel Fertin phone call;
- no whizzer and an aluminum dust cap: yes , the dustcap
acts as a heatsink and nothing to do with the 18khz.
- To reach 18khz: he prefered having no whizzer (with the problem
that a whizzer brings). He said that the combination of a
strong motor and a very light paper cone could get the jog done.
- The cabinet that was design by M.Fertin is a TQWT adapted for
the LB7 (The TL was my mistake; I looked at the picture a bit fast).
With this design you get bass down to 40hz and good quality
bass which for him is very important: bass that is precise et with
body (''qui a du corps'').
- the motor has a strong ferrite magnet and he says that with the
right building technique you get as good, as smoothe response
as with an alnico motor without the extra cost of and alnico.
You can't hear the difference between the two . He says that people should put the money that they save by using a ferrite
magnet instead of alnico in buying a good quality amp.
-He'll send me the frequency and impedance curves this week.
So I'll be back with further info....if you have any questions to
ask him, don't hesiate; too bad he doesn't speak English: he has
a wealth of info wiht his 30+year in audio and driver building.
I consider Michel Fertin's drivers as the ''old'' school of driver design:
high efficient, low qes-qts , light paper cone with a strong
motor, paper voice coil former, small magnetic gap. Driver you
can use without xover and a low power amp.
-
- no whizzer and an aluminum dust cap: yes , the dustcap
acts as a heatsink and nothing to do with the 18khz.
- To reach 18khz: he prefered having no whizzer (with the problem
that a whizzer brings). He said that the combination of a
strong motor and a very light paper cone could get the jog done.
- The cabinet that was design by M.Fertin is a TQWT adapted for
the LB7 (The TL was my mistake; I looked at the picture a bit fast).
With this design you get bass down to 40hz and good quality
bass which for him is very important: bass that is precise et with
body (''qui a du corps'').
- the motor has a strong ferrite magnet and he says that with the
right building technique you get as good, as smoothe response
as with an alnico motor without the extra cost of and alnico.
You can't hear the difference between the two . He says that people should put the money that they save by using a ferrite
magnet instead of alnico in buying a good quality amp.
-He'll send me the frequency and impedance curves this week.
So I'll be back with further info....if you have any questions to
ask him, don't hesiate; too bad he doesn't speak English: he has
a wealth of info wiht his 30+year in audio and driver building.
I consider Michel Fertin's drivers as the ''old'' school of driver design:
high efficient, low qes-qts , light paper cone with a strong
motor, paper voice coil former, small magnetic gap. Driver you
can use without xover and a low power amp.
-
More precision from the transcript that I received from Michel Fertin:
Design principles for reaching 18khz without a whizzer with the LB7:
-you have constant impedance at hf.
-the texture and shape of the membrane which permit a cone
break-up that is efficient.
-lightness of the mobile mass (mms: 0.85gr)
The addition of a whizzer in the case of the LB7 would only increase
the weight of the mobile mass, and more, it would add some
inteference with the main cone. The overall effect of adding a whizzer would be: less hf and more uneven hf response.
Choice of cabinet (TL_modified)
For drivers with a small diameter, this type of cabinet will give good
quality bass without dragging and also do not degrade too much the
quality of the med-high frequencies compare to an open-baffle.
Choice of a low qts for the LB7:
The qt of a driver reflects the impedance curve at around the
resonance frequency of the driver.The lower it is , the more the
misadaptation with the amplifier is important.You can couteract
this problem by: 1)increasing the qts with a resistor (not recommended) 2)increase the output impedance of the amp.
3) to use a cabinet that enable to lower the impedance around
the resonance (TL-Horn).
All the best drivers have a low qts(LB7:0.215). This permits of
having a fast low frequency response without draging)
Its's and advantage of the field coil driver to be able to ajust the voltage in order to vary the qts of the driver. It was shown
that most user of field coil adjust their drivers to get the lowest qts.
Choice of components for the LB12:
The LB7 was built with the aim of getting the best audiophile
sound :
- a very light mobile mass (2.5gr) and a very rigid membrane.
- a symetric magnetic circuit.
- an oversize-very powerful ferrite magnet (102mm)
- a system of internal rings that would stabilize the magnetic flux
thus giving the advantage of an alnico magnet without the
inconveniences (higher cost- demagnetization ).
- addition of copper ring that stabilize the impedance in the hf.
- sturdy aluminum basket and an open back
- a massive piece at the center of the cone link to the magnetic
circuit that would regularized the frequency response in the
middle frequencies.
The wooden phase plug in the LB12 breaks up the directivity
of the driver and permits an even response off axe.
The frequency plots for the LB12 will be available next week.
Translation from the transcript of Michel Fertin desingner
and manufacturer of the emspeaker LB7.
Design principles for reaching 18khz without a whizzer with the LB7:
-you have constant impedance at hf.
-the texture and shape of the membrane which permit a cone
break-up that is efficient.
-lightness of the mobile mass (mms: 0.85gr)
The addition of a whizzer in the case of the LB7 would only increase
the weight of the mobile mass, and more, it would add some
inteference with the main cone. The overall effect of adding a whizzer would be: less hf and more uneven hf response.
Choice of cabinet (TL_modified)
For drivers with a small diameter, this type of cabinet will give good
quality bass without dragging and also do not degrade too much the
quality of the med-high frequencies compare to an open-baffle.
Choice of a low qts for the LB7:
The qt of a driver reflects the impedance curve at around the
resonance frequency of the driver.The lower it is , the more the
misadaptation with the amplifier is important.You can couteract
this problem by: 1)increasing the qts with a resistor (not recommended) 2)increase the output impedance of the amp.
3) to use a cabinet that enable to lower the impedance around
the resonance (TL-Horn).
All the best drivers have a low qts(LB7:0.215). This permits of
having a fast low frequency response without draging)
Its's and advantage of the field coil driver to be able to ajust the voltage in order to vary the qts of the driver. It was shown
that most user of field coil adjust their drivers to get the lowest qts.
Choice of components for the LB12:
The LB7 was built with the aim of getting the best audiophile
sound :
- a very light mobile mass (2.5gr) and a very rigid membrane.
- a symetric magnetic circuit.
- an oversize-very powerful ferrite magnet (102mm)
- a system of internal rings that would stabilize the magnetic flux
thus giving the advantage of an alnico magnet without the
inconveniences (higher cost- demagnetization ).
- addition of copper ring that stabilize the impedance in the hf.
- sturdy aluminum basket and an open back
- a massive piece at the center of the cone link to the magnetic
circuit that would regularized the frequency response in the
middle frequencies.
The wooden phase plug in the LB12 breaks up the directivity
of the driver and permits an even response off axe.
The frequency plots for the LB12 will be available next week.
Translation from the transcript of Michel Fertin desingner
and manufacturer of the emspeaker LB7.
lrntglls said:
Advanced "motor" technology...thats VERY interesting...seems it deserves attention 🙂
tinitus said:
Curious. I was recently on the Linkwitz Labs website reading about driver distortion and if I understand it correctly he found that a significant portion of the distortion produced the driver he was testing was due to the voice coil disrupting the magnetic field produced by the permanent magnet. IIRC adding 'shorting rings' reduced this effect substantially. For reference: www.linkwitzlab.com/frontiers_3.htm section Q.
Is it possible that alnico is less susceptible to this effect, and that Fertin have used ferrite because with an improved design (shorting rings and the like) they can produce something that works as well using ferrite as with the alnico units?
Hmm, now I'm wondering what other full range driver manufacturers use shorting rings in their designs.
I'll be in Europe next year so I hope to have the opportunity to hear a pair of these legendary drivers. I wonder if they have factory tours... 🙂
Oh, for what it's worth I don't know anything about designing drivers, so if this is all common knowledge or has been discussed at length before, I apologise.
I think it was JBL that first designed a ferrite magnet driver using
shorting ring and was able to reduce distortion. I saw
a text on this site about this but not sure where exactly.
Michel Fertin said that there were no significant advantage
of using alnico except higher cost. A well design ferrite driver
will sound as good as alnico. I'm sure that this idea isn't
accepted by everyone here.
Don't get mix up: Emspeaker is Katy Fertin co. Michel Fertin is
her father helping her in the design and manufacturing of
Emspeaker's driver: the LB12-LB7 and a woofer coming soon.
Fertin Acoustic with the Fertin 20ex- model 7 surroundless driver
is Jean-Marie Semblat's co. Jean-Marie use to work for Fertin and
bought the co from Michel Fertin. The model 7 with no surround
is another story...
If you want to visit either Emspeaker or Fertin in Europe;
I can arrange a visit......
shorting ring and was able to reduce distortion. I saw
a text on this site about this but not sure where exactly.
Michel Fertin said that there were no significant advantage
of using alnico except higher cost. A well design ferrite driver
will sound as good as alnico. I'm sure that this idea isn't
accepted by everyone here.
Don't get mix up: Emspeaker is Katy Fertin co. Michel Fertin is
her father helping her in the design and manufacturing of
Emspeaker's driver: the LB12-LB7 and a woofer coming soon.
Fertin Acoustic with the Fertin 20ex- model 7 surroundless driver
is Jean-Marie Semblat's co. Jean-Marie use to work for Fertin and
bought the co from Michel Fertin. The model 7 with no surround
is another story...
If you want to visit either Emspeaker or Fertin in Europe;
I can arrange a visit......
Is the LB12 also with advanced design with shortrings like the LB7 ?
You are saying that there will be a woofer as well...do you know the size ?
You are saying that there will be a woofer as well...do you know the size ?
lrntglls,
Any idea of the price and expected availability of the 7" driver? And, is there a "waterfall" plot available?
Any idea of the price and expected availability of the 7" driver? And, is there a "waterfall" plot available?
The price for the LB is 250 euros each driver.
Transportation is free for US residents. They are available
at the present time. As for the frequency plots: I was supposed
to get them last week but still waiting.
Transportation is free for US residents. They are available
at the present time. As for the frequency plots: I was supposed
to get them last week but still waiting.
Le B15EX est un haut-parleur à haut rendement et fréquence de résonnance basse.
Son Qt modifiable grâce à son moteur à excitation permet une adaptation plus facile à toute sorte de baffle.
Emspeaker have a new 15inch(38cm) driver: BL15
- Ceramic or field coil: 8 or 16ohm.
- Very high efficiency (102.5db) with a low fs: 22hz.
Here are the specs: photo and frequency plot will follow.
Caractéristiques principales Paramètres
Thièle et Small
FR 22 Hz RCC 6,54 Ohms
W 100 Watts Qms 7,068**
Z 8 Ohms* Qes 0,149**
BP 23-5000 Hz Qts 0,146**
Mms 58 gr Rms 1,230**
BL 19,5** S 8,55 dm²
Xmax 7 mm Vas 791 L
FA 335** R 6,8 %**
Eff 100,2 dB** Le 0,9 mH
* Disponible également en 16 Ohms
** Variable avec la tension d’excitation
Son Qt modifiable grâce à son moteur à excitation permet une adaptation plus facile à toute sorte de baffle.
Emspeaker have a new 15inch(38cm) driver: BL15
- Ceramic or field coil: 8 or 16ohm.
- Very high efficiency (102.5db) with a low fs: 22hz.
Here are the specs: photo and frequency plot will follow.
Caractéristiques principales Paramètres
Thièle et Small
FR 22 Hz RCC 6,54 Ohms
W 100 Watts Qms 7,068**
Z 8 Ohms* Qes 0,149**
BP 23-5000 Hz Qts 0,146**
Mms 58 gr Rms 1,230**
BL 19,5** S 8,55 dm²
Xmax 7 mm Vas 791 L
FA 335** R 6,8 %**
Eff 100,2 dB** Le 0,9 mH
* Disponible également en 16 Ohms
** Variable avec la tension d’excitation
- Status
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