hoss
5,000+ posts
imma genius. so **** it!
what does it matter? you arent going to hear the difference in a few grams. look at the parameters if you need to, knowing the mms is going to tell you nothing that you want/need to know...
- Thread Starter
- #3
Less cone moving mass - faster bass (less dalay), and cone response. It's important fact for SQ systems. So, very light weight sub's cones which made from cellulose has a min. dalay.
hoss
5,000+ posts
imma genius. so **** it!
faster bass? last time i checked the speed of sound was 340.29 meters per second, and i dont understand how the cone weight is going to make it faster. as far as transient response, the most significant factor in a woofers response is the electrical Q and the Bl. moving mass can be compensated for, but is not what should be looked at when trying to judge woofers. if that is all you are interested in, you should compare top plates, gaps, t-yoke clearance, voice coil gauge windings, etc etc...
like i stated before, all this makes up the woofers parameters, which you should look at them before you judge solely on the components it is comprised of.
- Thread Starter
- #7
May be I am wrong. But this fact is important too
Warbleed
10+ year member
@$$hole
Mms has NOTHING to do with upper end frequency response at all. It also has NOTHING to do with any sort of delay.
You are a victim of believing a very illogical, poorly reasoned myth...
- Thread Starter
- #9
Thank's for discussion //content.invisioncic.com/y282845/emoticons/blush.gif.99bc659ee2012b7d826165e26fb5eebe.gif
I could be misunderstanding hoss's statements.....but I believe he was simply saying that if you are going to worry about a spec such as Mms, then you should worry about other inconsequential factors aswell. All those things are an important part of the subs overall design, but not really something the end consumer should spend time concentrating on or use as decision making criteria
Warbleed
10+ year member
@$$hole
There's no need to even refer to the speak of sound, because if one driver's cone was moving FASTER than another driver's cone, it would be playing a higher frequency. If one driver is moving faster, then it would complete more cycles per second, and thus be a higher frequency. Both drivers must travel at the SAME speed to reproduce the same frequency.
Qes and BL measure the same thing realistically. The biggest factors in low frequency response are Mms and BL, but the biggest factor for high frequency extension is neither, it's Le (inductance). After all, a voice coil is an inductor by nature (steel or air core, depending on if the coil is in or out of the gap), and inductors are of course, 1st order low pass filters. So the higher the inductance, the lower the frequency at which high frequency rolloff begins to occur.
So if our primary concern is high frequency extension, we want a low inductance most of all.
Now of course breakup modes and resonances also factor into high frequency response, but that accounts for peaks and nulls, and not so much the high frequency rolloff point of the speaker.
It is a common myth that Mms is a factor in what is ignorantly called "woofer speed", when in fact it has NO effect on the velocity of the driver at all.
Provided that it can be adequately controlled and is appropriate (I.E. Combined with the suspension yields the desired Fs), Mms really isn't much of a factor.
Now obviously in a high frequency driver we sacrifice efficiency with increased Mms, the change is proportionate, so it does NOT effect the high frequency rolloff point of the driver.
Mms is less significant from an efficiency standpoint in woofers because if we take two identical drivers, and we'll even say that they have identical T/S parameters save for Mms and Fs, obviously, and if we take a driver and add mass, we will raise Qes and consequently Qts, but we'll assume that there were slight motor accomodations to yield the same Qes without changing the coil or any other properties of the driver.
If you actually compare the response of the two drivers (Dan Wiggins has a GREAT graph comparing a raw driver's response with a driver with an inductor wired in series and a driver with more mms, and it is quite apparent that as expected, Mms has very little effect on response, other than efficiency, and Inductance has a huge effect on high frequency rolloff) you'll notice that the driver with higher Mms has lower 1 watt efficiency, but the same high frequency rolloff frequency. It will also have a lower low frequency F3 for any given alignment.
Mms isn't a bad thing, you just want the amount that is appropriate for the application. Same goes for BL, really.
As to the original poster's question, the Mms of the ID 12d4 V.3 is about 144 grams, going by the Sd, Cms, and Fs listed.
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