No, you don't want that. Unless you want a top (sat) and xo it at ~100Hz, you don't want it vented. At low frequencies the human ear is very insensitive to phase changes, above ~100Hz fb it starts to sound horrible. And you don't want the reflected muddy mid-garbage from the back of the driver/inside of the enclosure to come out of the port. It will sound much cleaner and detailed in a sealed compartment instead of a vented. TBH, I would not care that much about the Qes for the midrange.
The SPL response shown in the data sheet has nothing to do with the response you will see in your speaker. The response is largely controlled by the baffle geometry.
Well, again, it depends on what you need for your loudspeaker system. Looking at isolated parameters is not going to be a useful approach.
WHAT KIND OF SPEAKER ARE YOU TRYING TO DEVELOP?
Maybe I'm wrong but I just don't like the idea of using a stiff suspension to control freq response. You give up a lot of SPL, I'd rather see a strong motor for efficiency and deal with peaks with proper baffle and xo design as everyone says.
A stiff suspension does not mean "you give up a lot of SPL" (quite the contrary, in fact).
Please remember that the Thielle-Small parameters are used to describe the behaviour of a driver near its resonance frequency. I therefore don't think the Thielle-Small parameters are very relevant in the application intended here (although I have to admit that I don't know what the "intentions" of this loudspeaker system might be).
That may be true I just generally have not been impressed with high Qes, lower efficiency drivers in my own experience.
However if you are saying that a stiffer suspension on the same cone and motor will gain SPL, I would argue against that. Common sense would make the point that stiffer suspension would reduce ring, not only at resonation, but also at all other freq to a lesser degree. Restricting cone excursion will reduce SPL... period.
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one way to dynamics is a driver which is underutilized by having it perform only within a narrow freq range compared to its overall capability. then you look at those with a larger motor and good impulse response. I got a great result with Visaton AL200 that way in an OB (all DSPed for Xover and min EQ).
Intention: 3 units for home use, no sub, all passive XO, 1 amp.
ICG has a very good point on suspension and Xmas, stiff suspension somewhat reduce sensitivity but it enabled greater sound levels at 1 to 2 khz due to the stopping of cone resonances/breakups , some suspension with 0.2mmH have almost no breakup and can play very loud, there are 10' midranges which are meant to be used that way for electric guitar and pa, ex: driver #10, this is not what I want I think because I want a better sound dispersion to enable 2 m to 7 m distance from speakers. A 10' would need a XO which can only cross far or close with a resulting beam or dip at some distances.
I think the major factor for sensitivity is the magnet type and construction type.
Alnico is the most sensitive, ferrite second and NEO is the worst (look at ss illum.)
KOJA, my experience point to the contrary, DSp is no no for me, kills everything I need to hear. narrow band is also very bad, I hate drivers with inductance over 1mH (total with XO inductors) I prefer not to use 3 rd order but rare are the drivers which can only be 2n order low passed with tweeter. The first driver and driver #10 can fit this requirement, I found that midranges or fullrange with high inductances like 2mH in total kills the top end dynamics, the opposite of what it should do according to you
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ICG has a very good point on suspension and Xmas, stiff suspension somewhat reduce sensitivity but it enabled greater sound levels at 1 to 2 khz due to the stopping of cone resonances/breakups , some suspension with 0.2mmH have almost no breakup and can play very loud, there are 10' midranges which are meant to be used that way for electric guitar and pa, ex: driver #10, this is not what I want I think because I want a better sound dispersion to enable 2 m to 7 m distance from speakers. A 10' would need a XO which can only cross far or close with a resulting beam or dip at some distances.
I think the major factor for sensitivity is the magnet type and construction type.
Alnico is the most sensitive, ferrite second and NEO is the worst (look at ss illum.)
KOJA, my experience point to the contrary, DSp is no no for me, kills everything I need to hear. narrow band is also very bad, I hate drivers with inductance over 1mH (total with XO inductors) I prefer not to use 3 rd order but rare are the drivers which can only be 2n order low passed with tweeter. The first driver and driver #10 can fit this requirement, I found that midranges or fullrange with high inductances like 2mH in total kills the top end dynamics, the opposite of what it should do according to you
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Actually the VC and cone mass has more to do with sensitivity than anything else.
To clarify you're doing a 3 way, woofer passively crossed at 100hz or do I misunderstand you?
The woofer will be crossed around 200 - 400, this is preliminary.
My problem is to choose midrange because I find it most critical. I know good woofers and how to use them, but from 200 hz to 2 khz it is critical and few drivers sound good in that range. I don't like full ranges because most tend to shout at you. I am looking for a good midwoofer with good dispersion, solid sound down to 100hz and a natural roll-off, I think I will acquire driver 1 (2 pairs) and driver # 10 but the price is high on #10...
My problem is to choose midrange because I find it most critical. I know good woofers and how to use them, but from 200 hz to 2 khz it is critical and few drivers sound good in that range. I don't like full ranges because most tend to shout at you. I am looking for a good midwoofer with good dispersion, solid sound down to 100hz and a natural roll-off, I think I will acquire driver 1 (2 pairs) and driver # 10 but the price is high on #10...
I know that may seem counterintuitive, but please remember that we are looking at how the driver is operating well above it's resonance frequency. In this operation range, cone movement lags the voltage signal with a 90° phase lag. This is quite different to how the driver operates at frequencies well below the resonance, where the cone movement is in phase with the voltage input, and a stiffer suspension does indeed reduce cone movement.
You might also consider how the stiffness of the cone suspension determines the resonance frequency of the driver (fs). At a fixed mass of the cone + voice coil, higher stiffness gives higher fs. The efficiency of the driver increases with fs³ (see here). A stiffer suspension therefore results in higher SPL for the midrange.
Of course efficiency is increased around resonance but I thought we were talking about frequencies outside of resonance.
As far as whether the movement is in phase with signal or not, I'm not really sure how it is relevant. I'm sure it's possible that some freq could be emphasized by certain suspension properties but that would probably not be desirable.
At the fs the membrane 'wants' to move most, a stiff suspension keeps the membrane more in control so the usable lower frequency can be closer to the fs. That's relevant because you want to keep the Mms low and the motor as strong as possible to achieve a higher sensitivity but both factors lead to a rise in the fs.
That brings also a problem with it though, around the fs a phase change occurs. If the phase turn doesn't fall into the range of the crossover, it's usually much easier to design the filters. To keep the used range withing the (relatively) steady phase reduces the phase error and it mostly remains only the phase turn of the crossover itself. Besides the sound, without a good phase match you'll likely get interferences which causes lobes in the dispersion. While most HiFi enthusiasts don't care very much about the vertical dispersion, in PA it's much more important.
As I wrote, you ARE looking at how the driver operates well above resonance. Neglecting beaming (which is a function of cone diameter only) and cone breakup and similar resonances (which we are not considering here) the driver efficiency is approximately constant throughout its pass band.
We are getting off topic here. I'd suggest you read up on how electrodynamic drivers work, or you start a new thread.
Here's a pic that nicely shows what happens when ( & all other factors are held constant ) a drivers compliance tightens up.
This ( Japanese sourced ) pic is of a JBL le15a, before and after a reconer's re-surround.
The red trace is after the new surround is installed.
Note the squashed db scale. The response changes are really quite dramatic .
This ( Japanese sourced ) pic is of a JBL le15a, before and after a reconer's re-surround.
The red trace is after the new surround is installed.
Note the squashed db scale. The response changes are really quite dramatic .
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