Hi there,
I realise this is a pretty basic question, but I'm not sure about it..
If the strength of the motor is the same (somewhat hypothetical of course), is it mainly the extra Mmd that stops a subwoofer driver from 'flapping', when used in a subwoofer system?
I'm considering trying to use the FaitalPro 12FX600 in a vented subwoofer box. It appears to straddle between a woofer and a subwoofer in its design. They have provided a frequency response curve with a 45 degree off-axis plot, which makes me think it's intended as a woofer, but then they do this even with their 18" subwoofers.
Obviously from experience I know that if you try to put too much bass through a woofer (presumably with a lower Mmd) they do start to flap eventually.
Perhaps the surround has an influence as well?
TIA
I realise this is a pretty basic question, but I'm not sure about it..
If the strength of the motor is the same (somewhat hypothetical of course), is it mainly the extra Mmd that stops a subwoofer driver from 'flapping', when used in a subwoofer system?
I'm considering trying to use the FaitalPro 12FX600 in a vented subwoofer box. It appears to straddle between a woofer and a subwoofer in its design. They have provided a frequency response curve with a 45 degree off-axis plot, which makes me think it's intended as a woofer, but then they do this even with their 18" subwoofers.
Obviously from experience I know that if you try to put too much bass through a woofer (presumably with a lower Mmd) they do start to flap eventually.
Perhaps the surround has an influence as well?
TIA
I suppose I just mean distorting. But I'm pretty sure it is mostly the cone moving in a non-pistonic way. 'Breaking up' I think is the term that is used.
I think, though I may be wrong, the cone has more mass in a subwoofer than in a woofer. I believe this damping is there to help the sub produce the lower notes and is not just there to lower the Fs.
I think, though I may be wrong, the cone has more mass in a subwoofer than in a woofer. I believe this damping is there to help the sub produce the lower notes and is not just there to lower the Fs.
A vented box driver "flapping" noise makes me think of high excursion below Fb (box tuning frequency) where the vent output is out of phase with cone output, resulting in a lot of wind noise with little low frequency output, like a bird's wing. More MMD, making a stiffer cone, won't make any change to that noise.
If a driver with a "too light" cone is driven too hard in a high compression ratio horn, it's cone may buckle and cause excessive harmonic distortion, a different sound than "flapping".
Cone "break up" sound is generally the peaks and dips resultant from non-pistonic cone movement when driven outside of the specified frequency range of the speaker.
A surround or spider driven to near it's mechanical limit may also make a flapping sound, regardless of the enclosure type.
The FaitalPro 12FX600's "Xdamage" is 24.1mm, which could be the mechanical limit of it's surround or spider ("flap") or coil former hitting the back plate ("clack") or a combination of those.
Driven to Xmax (9.9mm) or a bit past that in a vented box with a steep HP filter a few Hz below Fb near it's Fs of 48Hz the 12FX600 should not have any "flapping" sound.
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Extra mmd is not preventing 'flapping'.
A much more heavier cone is difficult to be controlled by spider and surround than a lighter one when inserting a lot of watts.
For this in professional use (PA systems) the surrounds and spiders are usually stiffer than in home hifi.
If a woofers cone is made heavier, while all other parameter stay the same, Fs is lower, so you can reproduce lower frequency. What you loose is high frequency output and you need some extra power to drive it.
With some drivers you can actually use extra wheight on the cone to improve their performance in a subwoofer.
If you consider such a modification you should really know what you do and want.
"Flapping" has nothing to do with it.
With some drivers you can actually use extra wheight on the cone to improve their performance in a subwoofer.
If you consider such a modification you should really know what you do and want.
"Flapping" has nothing to do with it.
Well, first you need to describe what you want. Everything is tradeoff.
If it is for PA, you need high efficiency, high power, ruggedness, but you sacrifice low fr extension, and forget small box, it will be big.
If it is for home hifi, moderate listening level, power wattage is not that important, select one with lowest fs.
If it is for PA, you need high efficiency, high power, ruggedness, but you sacrifice low fr extension, and forget small box, it will be big.
If it is for home hifi, moderate listening level, power wattage is not that important, select one with lowest fs.
The purpose is lightweight PA.
I can’t find a driver of a similar price with similar parameters, with a neo magnet.
I think this is because the weight of a circa 700W sub starts at about 8kg, and since most manufacturers will be building their cabinets out of birch or marine ply, the weight saving probably doesn’t make sense.
I prefer to use softwood ply and just adding more bracing to get a similar stiffness. Given then that the cabinet weighs substantially less, the weight saving becomes relevant.
I can’t find a driver of a similar price with similar parameters, with a neo magnet.
I think this is because the weight of a circa 700W sub starts at about 8kg, and since most manufacturers will be building their cabinets out of birch or marine ply, the weight saving probably doesn’t make sense.
I prefer to use softwood ply and just adding more bracing to get a similar stiffness. Given then that the cabinet weighs substantially less, the weight saving becomes relevant.
I wouldn't worry too much about driver weight.
Most the weight is the enclosure
But your approach is there.
Bass Players have this light fascination as well.
They often use 1/2" ply instead of 3/4 " ply
which has a weight savings. and add bracing.
comparing the weight of a single sheet is often big difference.
And likewise your method as well. Back when more variety of wood was available
at home centers. It is a basic science of taking every 1/2" sheet off the rack
and buying the lightest one.
Wheels help of course, tilt slide and plop. once on the wheels its rolling
no lifting. tilt n slide
part the misleading of it I guess. they make small cabinets that must be carried.
when taller larger cabinets just tilt n slide. no carry just wheels.
Most the weight is the enclosure
But your approach is there.
Bass Players have this light fascination as well.
They often use 1/2" ply instead of 3/4 " ply
which has a weight savings. and add bracing.
comparing the weight of a single sheet is often big difference.
And likewise your method as well. Back when more variety of wood was available
at home centers. It is a basic science of taking every 1/2" sheet off the rack
and buying the lightest one.
Wheels help of course, tilt slide and plop. once on the wheels its rolling
no lifting. tilt n slide
part the misleading of it I guess. they make small cabinets that must be carried.
when taller larger cabinets just tilt n slide. no carry just wheels.
yeah a friend of mine in one of my bands uses barefaced audio. 2x12" neo. I believe the cabinet is softwood with a harder veneer on the outside.
Well, the thing is I have in the past (and am looking to again) worked as a sound engineer with equipment- solo/ one man, so weight is critical. And wheels do not go up staircases, which I have faced a lot. (of course I do use castors as well).
I've built a variety of cabinets before, some for fun, some with a computer model. I have experimented with different materials and have stuck with softwood ply. Not eucalyptus or something like that- it's very difficult to work. Other species are much easier to work, and with the equipment I have (I use Freud blades which leave a finish that looks like its been planed!) it works practically as well as birch, only faster and easier owing to the softness. I finish it with a very generous layer of UPOL raptor, which is great and is tough enough to somewhat make up for the softness of the face.
I've weighed it against birch- and the stuff I prefer is nearly 40% lighter. I haven't made a single 12" cab before, but I'm guessing it comes out about 20kg or more. Add a 12PS100, for example and the driver is a reasonable weight. With the ply I use, I'm looking at 13kg for the same box (including some extra bracing). In this scenario, I think a weight saving of 3kg is quite reasonable for the money, personally.
So that's why I'm interested in neo magnets on small subs, really. I know there is the 12s330 by BMS, which is very reasonably priced, but I just don't want or need the extra extension.
Well, the thing is I have in the past (and am looking to again) worked as a sound engineer with equipment- solo/ one man, so weight is critical. And wheels do not go up staircases, which I have faced a lot. (of course I do use castors as well).
I've built a variety of cabinets before, some for fun, some with a computer model. I have experimented with different materials and have stuck with softwood ply. Not eucalyptus or something like that- it's very difficult to work. Other species are much easier to work, and with the equipment I have (I use Freud blades which leave a finish that looks like its been planed!) it works practically as well as birch, only faster and easier owing to the softness. I finish it with a very generous layer of UPOL raptor, which is great and is tough enough to somewhat make up for the softness of the face.
I've weighed it against birch- and the stuff I prefer is nearly 40% lighter. I haven't made a single 12" cab before, but I'm guessing it comes out about 20kg or more. Add a 12PS100, for example and the driver is a reasonable weight. With the ply I use, I'm looking at 13kg for the same box (including some extra bracing). In this scenario, I think a weight saving of 3kg is quite reasonable for the money, personally.
So that's why I'm interested in neo magnets on small subs, really. I know there is the 12s330 by BMS, which is very reasonably priced, but I just don't want or need the extra extension.
The neo Eminence Kappalite 3012LF 12" has similar excursion, is lighter and considerably less expensive than the FaitalPro 12FX600.
The 3012LF also has a lower Fs, 37Hz compared to 48Hz.
Worth a comparison.
Or 3015
You get better efficiency with 15"
But just use drivers friendly small boxes.
Lower tuning less unloading for your flapping.
You have to look at what you loose in fullspace.
Why you even see 18" in small boxes.
Same response as a 12"
But your tuned 30 Hz not 55 Hz
So the hit way more accurate.
same concept if 15"
not much more bass in small box but lower tuning.
trying be tuned below the common Eq boost.
You get better efficiency with 15"
But just use drivers friendly small boxes.
Lower tuning less unloading for your flapping.
You have to look at what you loose in fullspace.
Why you even see 18" in small boxes.
Same response as a 12"
But your tuned 30 Hz not 55 Hz
So the hit way more accurate.
same concept if 15"
not much more bass in small box but lower tuning.
trying be tuned below the common Eq boost.
Many bass cabinets will have a lower frequency below which the driver becomes unloaded and the motion of the diaphragm wil result in very little output.
The solution with higher output designs is usually a high pass filter to remove the frequencies below the effective bandwidth of the cabinet design.
This reduces the amount of 'Cone Flap' without effecting the lower frequency output too much.
Some speaker drivers have physical suspension characteristics that will resist over excursion, others will easily hit x-mech - Knowing which is often not that easy to evaluate.
Cabinets can be tuned lower ,or use sealed chambers that do not unload the driver. This coupled with a reduction in output can mean that the speaker can be effectively used without a high pass filter, relying on the bandwith of the audio signal, which might be considered as the normal default.
The solution with higher output designs is usually a high pass filter to remove the frequencies below the effective bandwidth of the cabinet design.
This reduces the amount of 'Cone Flap' without effecting the lower frequency output too much.
Some speaker drivers have physical suspension characteristics that will resist over excursion, others will easily hit x-mech - Knowing which is often not that easy to evaluate.
Cabinets can be tuned lower ,or use sealed chambers that do not unload the driver. This coupled with a reduction in output can mean that the speaker can be effectively used without a high pass filter, relying on the bandwith of the audio signal, which might be considered as the normal default.