Exactly. It does not matter how is big signal level in respect to signals of other frequencies, if it excites ringing, when an ignorant head rings like a bell.
ALL fullrange drivers would benefit from EQ.
ALL drivers, period.
I think the question would be more like: ''what is the most affordable, interesting, driver that i could EQ for good final results ?''
Maybe a wild stallion like the Dayton PS180 ? Or his bigger brother the PS220 ?
EQing is limited in the first 2 octaves by the Xmax, basically.
EQing is limited in the last 2 octaves by the Sd/Mms ratio, basically.
So, look for the highest Sd/Mms ratio (i'd say north of 12cm² per gram) and try to get the driver with lowest Fs (unless you plan a FAST project) and highest Xmax.
Mid 6 octaves are pretty much EQable without being bothered by any mechanical limits, so it's not a big concern...
ALL drivers, period.
I think the question would be more like: ''what is the most affordable, interesting, driver that i could EQ for good final results ?''
Maybe a wild stallion like the Dayton PS180 ? Or his bigger brother the PS220 ?
EQing is limited in the first 2 octaves by the Xmax, basically.
EQing is limited in the last 2 octaves by the Sd/Mms ratio, basically.
So, look for the highest Sd/Mms ratio (i'd say north of 12cm² per gram) and try to get the driver with lowest Fs (unless you plan a FAST project) and highest Xmax.
Mid 6 octaves are pretty much EQable without being bothered by any mechanical limits, so it's not a big concern...
some of the highest Sd/Mms ratio (*not all fullrange drivers):
Dayton PS220-8 : 25,76cm² per gram
Tang Bang W8-1808 : 23,33cm² per gram
Dayton PS180-8 : 18,96cm² per gram
Tang Bang W3-1364 : 18,29cm² per gram
Dayton PS65LP-4 : 18.04cm² per gram
Tang Bang W5-2143 : 15,69cm² per gram
Faital Pro 3FE22 - 16 ohms : 13,13cm² per gram
Faital Pro 4FE32 - 4 ohms : 12,63cm² per gram
Fostex FF125WK : 10,00cm² per gram
Faital Pro 18FH500 : 8,28cm² per gram
Of course, bigger Sd will end up having directivity limitations.
My preference for a true fullrange speaker (1-way) would be with a nominal 8'' driver but with a FAST (2-way) i'd probably prefer something between 4'' and 6.5''. Usually easier to EQ-correct in the top end and also less beaming.
Dayton PS220-8 : 25,76cm² per gram
Tang Bang W8-1808 : 23,33cm² per gram
Dayton PS180-8 : 18,96cm² per gram
Tang Bang W3-1364 : 18,29cm² per gram
Dayton PS65LP-4 : 18.04cm² per gram
Tang Bang W5-2143 : 15,69cm² per gram
Faital Pro 3FE22 - 16 ohms : 13,13cm² per gram
Faital Pro 4FE32 - 4 ohms : 12,63cm² per gram
Fostex FF125WK : 10,00cm² per gram
Faital Pro 18FH500 : 8,28cm² per gram
Of course, bigger Sd will end up having directivity limitations.
My preference for a true fullrange speaker (1-way) would be with a nominal 8'' driver but with a FAST (2-way) i'd probably prefer something between 4'' and 6.5''. Usually easier to EQ-correct in the top end and also less beaming.
Sd/Mms ratio is pretty much equivalent as the Power to weight ratio in sports car. Maximum output for minimum weight equals better overall performance and feeling.
That is why a stock McLaren 720s will outclass a stock Nissan GTR on any given racetrack, even though both are very capable vehicles.
That is why a stock McLaren 720s will outclass a stock Nissan GTR on any given racetrack, even though both are very capable vehicles.
The problem I have with this analogy is that neither of the parameters you used of the driver has anything to do with power.
It's lacking the motor variable needed to move the membrane. You're only giving the ratio of lowest weight to surface area. It still needs some power to move.
Hi Jon,
I think the ratio you are looking for is BL/Mms.
BL = Motor force = Strength of magnet X length of wire given in Newton/Ampere
Mms = mass of Diaphram + air
One think I learned, is getting the specs of the speaker you want is one thing, getting it to integrate properly in a cabinet is another story.
Low Mms and low Fs present a very big problem. For example in the SEAS FA22RCZ. Has a low Mms for an 8 inch at only 12 gram. But to get the low Fs , they have to use a very low compliance spring, which basically means a very loose spring. The problem is when you stick the speaker in a cabinet, the air also acts like a spring and that brings up the resonance Fs. So in the SEAS, when I stick into a 40+ litre cabinet, Fs gets pushed to about 90Hz. The Vas is 120 litres, so the spring behaves the equivalent of 120 litres of air, so to make the compression of air inside the cabinet negligible, you would need to a box significantly larger than your Vas for the Fs to stay the same.
So moving back into this topic. If you wanted a low mass speaker with low Fs, you need a big box. To have an idea, look at Audionote. Very large boxed 8" high efficiency speakers. They sound great and I love the sound, even though I don't own one.
Oon
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You're right, the analogy is far from being perfect. On the other hand, the Bl numbers are usually coherent with the driver's design.
Let's take some from my list:
18FH500 = 59,68cm² per 1 Bl
PS220 = 35,19cm² per 1 Bl
W5-2143 = 17,31cm² per 1Bl
4FE32 = 12,97cm² per 1 Bl
More surface usually equals less motor per sq.cm.
But is it really a problem? Not in our fullrange questionning.
Unless we stumble upon a driver similar to the PS220 that is only equipped with a 2.3TM motor.
Let's take some from my list:
18FH500 = 59,68cm² per 1 Bl
PS220 = 35,19cm² per 1 Bl
W5-2143 = 17,31cm² per 1Bl
4FE32 = 12,97cm² per 1 Bl
More surface usually equals less motor per sq.cm.
But is it really a problem? Not in our fullrange questionning.
Unless we stumble upon a driver similar to the PS220 that is only equipped with a 2.3TM motor.
Let's take another animal: some high-end tweeter made of Be:
Transducer Lab
Mms: 0.23g
Sd: 6.7cm²
Bl: 3.4
So that is a 29,13cm² per gram, which is truly excellent. That's a tweeter, though...
Now, there is only 1,97cm² workload per 1tm. But then again, that's a tweeter. That's possible only because it's made to reproduce high frequencies.
... and even if those specs are good, i wouldn't be interested in that driver!
Transducer Lab
Mms: 0.23g
Sd: 6.7cm²
Bl: 3.4
So that is a 29,13cm² per gram, which is truly excellent. That's a tweeter, though...
Now, there is only 1,97cm² workload per 1tm. But then again, that's a tweeter. That's possible only because it's made to reproduce high frequencies.
... and even if those specs are good, i wouldn't be interested in that driver!
We can't honestly compare these two tweeters from different technologies, but still: another high-end driver:
RAAL: 140-15D
Sd equivalent 21cm² and Mms equivalent of 0.022g
That's 954cm² per gram. Maybe that explains why ribbons are so agile in the last audible octave (and beyond)...
RAAL: 140-15D
Sd equivalent 21cm² and Mms equivalent of 0.022g
That's 954cm² per gram. Maybe that explains why ribbons are so agile in the last audible octave (and beyond)...
Jon,
You may find this article interesting. Looking at your taste so far, seems what you are interested in is high efficiency speakers which I also like. The reason that high efficiency speakers work and has a very likeable sonic characteristics is the motor strength to mms ratio, assuming the same Sd.
High Efficiency Speakers
You may find this article interesting. Looking at your taste so far, seems what you are interested in is high efficiency speakers which I also like. The reason that high efficiency speakers work and has a very likeable sonic characteristics is the motor strength to mms ratio, assuming the same Sd.
High Efficiency Speakers
Bose 901s need the equalizer to sound right. I believe there were compatibility issues between the generation of speaker and the generation of the eq, so even in the redesign they did not try to make the correction the physical driver. 9 identical drivers at 1 ohm each, one pointed at the listener while the rest reflect off the wall behind them.
Bob
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