Lookie what dave made me

[galacticmonkey 5,000+ posts]

My point was it wouldnt work too well if a sub had a 2.5" VC and quad stiff spiders.

But thats not the case here.

 

[grimreper912003 5,000+ posts]

So now lets all just be pals again, sheesh!

Well I have to be nice to you... you have my ish //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[PV Audio 5,000+ posts]

what is the point of having a set of spiders so stiff that it takes 3kw + to make the sub move? wouldn't it be far more efficient to use less spiders and thus much less power to reach reasonable excursion levels?No point in having to throw 3kw on a sub with 5 spiders and have it sound just the same as a sub with 2 spiders and 1000w. imo

This is a good question and is related to the same question where if you have two speakers: both 12" cones with the same surface area and both are at xmax at 20mm at the same frequency, why is the one considered the SPL woofer going to be louder than the SQ woofer? Well, the matter is almost always due to force. Think about this: you can lightly hit your fist on the table 5x a second or you can slam your fist on the table 5x a second using the same distance. The difference between the two is the force imparted on the surface. The same applies here. You need high power handling because when you are using drivers with incredibly high motors and large voice coils, you are imparting more force on the cone. BL, or the force of the motor, is actually defined by its name: B*L. B is the magnetic field produced by the motor while L is the length of the voice coil. So while your two speakers might be moving the same distance, the SPL woofer is likely producing more force.
So, why do people use subwoofers with incredibly stiff spiders? Because to keep a speaker controlled at high output levels, you need a suspension that can keep the cone linear. The voice coil is naturally going to be large in order to handle high power needs and will be stroking quite ferociously, so you need to be able to keep it aligned in the gap. Otherwise, your huge motor and VC are useless if the speaker reaches Xmech before it can produce full output. Also, to keep a respectable mechanical Q (Qms), you need a suspension that is able to keep the cone linear as well.

If my reasoning is wrong, please let me know //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[audioholic 5,000+ posts]

Depends on what ur going for duder. 15mm xmx spl subs are for SPL and thats ALL they were meant for.
If you wanna get loud and sound good then your 300 mm xmax low powered sub does the job well.

But SPL subs dont NEED much excursion 2 get loud, all they need is high BL, High watage handling and the ability to keep the cone from flying away or crashing into the backplate.

Even in an SPL application, more excursion, all other factors being equal, will mean more SPL. The fact that most SPL setups run a vented enclosure with the burp being at, or very near, enclosure tuning complicates matters, but cone displacement still plays a key role. The reason SPL rigs have given rise to the notion that excursion isn't important is because the industry made such a huge swing towards 'xmax is everything' many years ago now that any divergence from this mindset tends to make people go 'wow, excursion isnt very important' when the truth is it is still a key factor, but is merely balanced with other factors that play a larger role in an SPL environment than they otherwise would in a daily listening environment where the signal is transient. Motor force (BL) plays a larger role in that SPL environment, again because the system is playing very near enclosure tuning, where efficiency of the enclosure peaks, and cone excursion is minimized, thus giving the side effect of more cone dampening, which means more force is required to move the cone a given distance. More force being needed to move the cone a given distance means more wattage, which is why power handling then becomes a larger factor in the SPL realm, which ties into what PV Audio said above.

 

[tommyk90 5,000+ posts]

You guys are making this all too scientific and junk.

I build box, drop in sub, and it go boom. win.

 

[audioholic 5,000+ posts]

Im well aware of your trial and error reasoning Tommy, and with your situation I agree its the right path to chose. But science created the situation that allows you to chose that path successfully. The key is a balance between the two principals... knowing when to stop calculating and start the trial and error method.

//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[tommyk90 5,000+ posts]

Im well aware of your trial and error reasoning Tommy, and with your situation I agree its the right path to chose. But science created the situation that allows you to chose that path successfully. The key is a balance between the two principals... knowing when to stop calculating and start the trial and error method.
//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Sorry, it's hard to decipher sarcasm via internet posts.

Of course I play with theories as well. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

But in the end, as you said, trial and error ends up being the most effective way of testing. Theories do give me ideas and a place to start though.

 

[S.B.C. 10+ year member]

I know how things work, and obviously certain subs appeal to certain people. What I am referring to is the overwhelming surge of people running spl subs in their daily beaters...not talking about comps, that's a totally different story. I guess I'm just surprised that a lot of people will throw sq out the window in order to get an extra 2-3db while at the same time needing a ton of people and electrical upgrades.

When you've never been loud

this comes outta your mouf

i kid i kid

or do i

 

[audioholic 5,000+ posts]

No need for an apology, I didnt take your comment as a slight. You and I have discussed this topic enough in the past that I understood what you meant Tommy.

 

[tommyk90 5,000+ posts]

No need for an apology, I didnt take your comment as a slight. You and I have discussed this topic enough in the past that I understood what you meant Tommy.

//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

lub j00 too.

 

[sundownz Pro Seller]

This is not always the case.
A stiffer suspension in some cases can be louder, even on the same power.

I'll be doing some testing regarding this over the next couple weeks. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Hey Tommy -- what application was that in that you got louder with a harder suspension on the same power ? Was it with the exact same sub simply with a harder spider ?

In every box I've ever tested at the same power softer suspension got louder. This has been true in all of my boxes and several of Team Members.

Not saying you are wrong -- I would just really like to know for my reference and so I can also test it ! //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[PV Audio 5,000+ posts]

You guys are making this all too scientific and junk.
I build box, drop in sub, and it go boom. win.

Ain't that the truth. "Hey guys! I just hit a 141 with my 15" Type R!" *tommy creates a thread* "Hey guys! I'm in the 150s with my 10" Type R!" //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[marcotheclepto 10+ year member]

Well, the FS can also be effected but I have a nice heavy coil so hopefully that helps.
I used to run 8"s and that surprised people. I was getting sick of the big subs. I have had 18"s 15"s 12"s and 8"s. 10" is the only one left.

6.5 //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[marcotheclepto 10+ year member]

Ain't that the truth. "Hey guys! I just hit a 141 with my 15" Type R!" *tommy creates a thread* "Hey guys! I'm in the 150s with my 10" Type R!" //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

hahaha

 

[tommyk90 5,000+ posts]

Hey Tommy -- what application was that in that you got louder with a harder suspension on the same power ? Was it with the exact same sub simply with a harder spider ?
In every box I've ever tested at the same power softer suspension got louder. This has been true in all of my boxes and several of Team Members.

Not saying you are wrong -- I would just really like to know for my reference and so I can also test it ! //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I've seen it happen over time with my DD's.

I had my original 9510 for 2 years and it slowly became quieter as the suspension got more broken in. Same power. I've heard of the same thing happening with a number of db drag guys.

In one specific case a db drag competitor I know actually lost somewhere in the area of .5 dB switching from 9512's to 3512's, even though he wasn't running much power (i think it was around 2kw per sub). In theory the 3512's should have been louder because of a softer suspension and would have been reaching xmax with that power, but 9512's are just so sickly efficient that even with less than maximum power they are louder.

I'll be testing this more thoroughly with a new sub I acquired. Detailed tests including voltage drop, impedence rise, and clamped power at 500, 1000, 1500, 2000, and up from there until the sub maxes out.

Once I get those numbers down I'll be dropping in a recone with a much stiffer suspension and doing the same tests.