This is a theoretical and basics exercise. It is important knowledge and still not much exists in the forums or the internet elsewhere.
What makes a midrange driver a midrange driver? Assume a pure pistonic driver for analysis.
What are the ways to achieve a low freq cutoff?
-is it.......limit cone excursion to limit LF and shorter coil length=less LF???
What are the ways to achieve a high freq cutoff?
-is it .......shorter coil length=more HF range & vice versa???
I know only these methods, what are the other ways?
Please post any external links here.
Thank you🙂
What makes a midrange driver a midrange driver? Assume a pure pistonic driver for analysis.
What are the ways to achieve a low freq cutoff?
-is it.......limit cone excursion to limit LF and shorter coil length=less LF???
What are the ways to achieve a high freq cutoff?
-is it .......shorter coil length=more HF range & vice versa???
I know only these methods, what are the other ways?
Please post any external links here.
Thank you🙂
Mid has no need for long cone travel.
This allows a much shorter voice coil that is inherently much lighter.
The lower moving mass allows extension to higher frequencies than a long travel speaker.
Now that you have a shortish voice coil, you can economically look at underhung and overhung coil/gap topologies.
This allows a much shorter voice coil that is inherently much lighter.
The lower moving mass allows extension to higher frequencies than a long travel speaker.
Now that you have a shortish voice coil, you can economically look at underhung and overhung coil/gap topologies.
Thank you for your reply.
Do you mean to say that by controlling the MMS you control the frequency response?
Or are there any definite methods at all, by which you can dictate the frequency range in which the driver will work? or is it "trial and error" method?
Do you mean to say that by controlling the MMS you control the frequency response?
Or are there any definite methods at all, by which you can dictate the frequency range in which the driver will work? or is it "trial and error" method?
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Take a look at common Mid-Bass drivers. If you want deep bass, you lose high end. If you want the high end to reach up to the tweeter, you lose bass.
Each driver has its own limit practical range of function. If you look at the Bowers/Wilkins (B&W) CM series or the 800 series, the midrange driver seems to be a common moderately large mid-bass, until you look closer and see the driver has NO Suspension. There is no accordion pleat or half dome roll around the edges. The cone, it fastened rigidly to the frame.
Why? Well with no need for bass capability, there is no need for long excursion, and therefore no need for suspension or surrounds. But, a speaker like this has a very limited range in which it can work. That's OK, because it only needs to work in a limited range.
Experience the B&W CM9 - Bowers & Wilkins | B&W Speakers
The yellow midrange speaker covers 350hz to 4khz.
Now to some extent it depends on how you define Mid-Range.
Frequency is typically divided up into THREE 3 octave ranges. If we start at 30hz, then bass cover up to 240hz. Three octaves of midrange would then be 240hz to 1920hz. Highs would then be 1920hz to 15,360hz, which reasonably cover the practical range.
However, how the frequency range is theoretically divided has little to do with the practical necessities of the drivers you have to work with. What constitutes midrange in a practical system depends on the capabilities of the various drivers lining up with each other.
The practical world is very different than the theoretical world.
For example, the peak POWER band for orchestral music is in the 250hz to 500hz range with the center at 355hz. If you crossover below 250hz, then count on having a strong midrange driver to handle that peak power. If you crossover above this at 500hz or 800hz, that pushes the Mid/High crossover up very high. If we assume 3 octaves, with Bass/Mid of 500hz, the Mid/High is around 4khz. If the Bass/Mid is 800hz, then the Mid/High is around 6400hz.
What make a Midrange a Midrange is that it is able to cover the range you need covered, and yes, there are various design parameters that can be adjusted to optimize a driver for a particular range - the cone, the suspension, etc....
Just a few thoughts.
Steve/bluewizard
Each driver has its own limit practical range of function. If you look at the Bowers/Wilkins (B&W) CM series or the 800 series, the midrange driver seems to be a common moderately large mid-bass, until you look closer and see the driver has NO Suspension. There is no accordion pleat or half dome roll around the edges. The cone, it fastened rigidly to the frame.
Why? Well with no need for bass capability, there is no need for long excursion, and therefore no need for suspension or surrounds. But, a speaker like this has a very limited range in which it can work. That's OK, because it only needs to work in a limited range.
Experience the B&W CM9 - Bowers & Wilkins | B&W Speakers
The yellow midrange speaker covers 350hz to 4khz.
Now to some extent it depends on how you define Mid-Range.
Frequency is typically divided up into THREE 3 octave ranges. If we start at 30hz, then bass cover up to 240hz. Three octaves of midrange would then be 240hz to 1920hz. Highs would then be 1920hz to 15,360hz, which reasonably cover the practical range.
However, how the frequency range is theoretically divided has little to do with the practical necessities of the drivers you have to work with. What constitutes midrange in a practical system depends on the capabilities of the various drivers lining up with each other.
The practical world is very different than the theoretical world.
For example, the peak POWER band for orchestral music is in the 250hz to 500hz range with the center at 355hz. If you crossover below 250hz, then count on having a strong midrange driver to handle that peak power. If you crossover above this at 500hz or 800hz, that pushes the Mid/High crossover up very high. If we assume 3 octaves, with Bass/Mid of 500hz, the Mid/High is around 4khz. If the Bass/Mid is 800hz, then the Mid/High is around 6400hz.
What make a Midrange a Midrange is that it is able to cover the range you need covered, and yes, there are various design parameters that can be adjusted to optimize a driver for a particular range - the cone, the suspension, etc....
Just a few thoughts.
Steve/bluewizard
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It is not necessary to cover 3 octaves evenly with every unit. We have many 3-way speakers that break that rule, most of them actually.
A wide range mid is always a compromise. I dont know of factory secrets but if we study T/S parameters and description of highly regarded Scanspeak, Accuton, SEAS specified 3"- 5" mids/midwoofers/wideranges, we can see differencies that are common to these. Look at compliance, inductance, Mms, Qms, VAS, Fs etc. How it is done, varies. Mostly often it is done by changing cone and surround.
A wide range mid is always a compromise. I dont know of factory secrets but if we study T/S parameters and description of highly regarded Scanspeak, Accuton, SEAS specified 3"- 5" mids/midwoofers/wideranges, we can see differencies that are common to these. Look at compliance, inductance, Mms, Qms, VAS, Fs etc. How it is done, varies. Mostly often it is done by changing cone and surround.
Well...
Maybe you mean the right thing, but I'm always getting angry when someone says that a lower mass gives higher frequency extension.
It is right that a higher voice coil mass reduces high frequency output, because this mass forms a lowpass together with the stiffness of the cone. But this is only valid when the cone does not move as a piston anymore - in this frequency range you should consider a lowpass anyway.
There's no other effect of the drivers moving mass with regards to high frequency output. This is hard to understand, especially for high end audiophiles, which were always told that a tweeter needs low mass for good high frequency response.
high frequency would be its ability to vibrate exstremely fast ? 😛
btw, regarding Xmax
every bit of unused wire outside the magnet gap is wasted energy
one reason why less Xmax often also means higher sensitivity
so if you know exactly how its going to be used, it will be possible to optimise the design
and btw, all modern tweeters are underhung, with very little voice coil
because they can be optimised for almost all conditions
meaning, they are not supposed to move much
genuine midrange drivers are a bit rare
Accuton makes them
but most others just change a few things on one of their small midbass drivers
btw, regarding Xmax
every bit of unused wire outside the magnet gap is wasted energy
one reason why less Xmax often also means higher sensitivity
so if you know exactly how its going to be used, it will be possible to optimise the design
and btw, all modern tweeters are underhung, with very little voice coil
because they can be optimised for almost all conditions
meaning, they are not supposed to move much
genuine midrange drivers are a bit rare
Accuton makes them
but most others just change a few things on one of their small midbass drivers
AndrewT probably tried to compare a sub to a tweeter in broad terms.
I believe lesser the mass the more accurate the reproduction.
Accuton drivers comparision.
DiamondBD50-6-039 Vs CeramicC50-8-044 (both listed as midrange drivers)
Freq resp= (800-30KHz) Vs (800-12KHz) {>double the bandwidth}
Sensitivity=93 Vs 88
Sd= 23.8 Vs 23.8 (same cone area)
Mms= 1.71 Vs 1.19 (hmmm.....43% heavier)
Cms= 0.175 Vs 0.147
Rms= 1.38 Vs 2.64 (91% less resistance to movement!!!!!)
BI= 5.64 Vs 3.13 (80% more intense field)
Xmax= +- 0.2mm Vs +- 0.75mm
Can we frame any rule using this data?
I believe lesser the mass the more accurate the reproduction.
Accuton drivers comparision.
DiamondBD50-6-039 Vs CeramicC50-8-044 (both listed as midrange drivers)
Freq resp= (800-30KHz) Vs (800-12KHz) {>double the bandwidth}
Sensitivity=93 Vs 88
Sd= 23.8 Vs 23.8 (same cone area)
Mms= 1.71 Vs 1.19 (hmmm.....43% heavier)
Cms= 0.175 Vs 0.147
Rms= 1.38 Vs 2.64 (91% less resistance to movement!!!!!)
BI= 5.64 Vs 3.13 (80% more intense field)
Xmax= +- 0.2mm Vs +- 0.75mm
Can we frame any rule using this data?
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I suspect he was comparing a midrange and a midwoofer. I suspect others are doing this as well. If you are not comparing a midrange with a midwoofer it might be useful to state this.
If you are comparing a midrange versus a midwoofer might I suggest you look at the specs from the Scan-Speak or SEAS ranges which make similar sized midranges and midwoofers. Accuton make very expensive speaker drivers and are consequently a bit unrepresentative.
No.
Yes: a stiffer cone leads to higher bandwidth because the first break-up frequency is shifted upwards.
tinitus said:
In usual magnet designs you'll get the highest efficiency when the coil uses some amount from the stray field around the air gap, which means that it must have a little overhang.
please note I specificly said unused coil wire
and by that I meant to say ... more overhang than is actually being needed/used will be wasted energy
ofcourse some safety margin will always be needed
question is how much
(still comparing midrange driver vs small midbass ... yes, because that is the reality ... but cost is no object yet, is it ? )
btw, best midrange might have half roll fabric/cloth surround
mostly only seen on widerange drivers
but I think Accuton uses it
I am not a Accuton fanatic, even if I may sound like one
but they do get some things right
but if using rubber and no cloth fabric surround, at least it should be much smaller
this kind of surround you may find on small PC drivers
they use it, and have no idea
it's a funny world
mostly only seen on widerange drivers
but I think Accuton uses it
I am not a Accuton fanatic, even if I may sound like one
but they do get some things right
but if using rubber and no cloth fabric surround, at least it should be much smaller
this kind of surround you may find on small PC drivers
they use it, and have no idea
it's a funny world
Well, I think that is precise enough for such a forum.
The surround is really difficult. A pure midrange does not need much excursion, so a small surround is not bad. I optimized once a midrange driver which suffered from a nasty circumferential mode at ~900 Hz (you'll guess, it was a 17 cm driver). I simply advised the manufacturer to use a much stiffer surround (it was an double roll already, but rubber 😀 ). Worked. Reason was that the cone itself wasn't stiff enough (but I couldn't change it for design reasons), and it needed support on the outer edge. OK, now it is not usable below 200 Hz, but who wants to use a midrange below that anyway?
Here is a nice poster about speaker cone design, also some hints of other aspects by Klippel.
http://www.klippel.de/fileadmin/kli...ture/Papers/KLIPPEL_Cone_Vibration_Poster.pdf
Loudsoft (Larsen) has some tools for design... a demo of the program - see how parameter changes make an effect FINECone demo video
http://www.klippel.de/fileadmin/kli...ture/Papers/KLIPPEL_Cone_Vibration_Poster.pdf
Loudsoft (Larsen) has some tools for design... a demo of the program - see how parameter changes make an effect FINECone demo video
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