Rumors on Sub size/ end them here

[PendulousThread 10+ year member]

hey I was wondering If anyone knew of any articles, threads or could tell me the advanteges/disadvanteges of diffrent size subs, I've heard so many rumors about speaker size I dont know what to belive 10's are the best NO 18's are the best etc etc. you get the idea. Any info that gives me a concrete definition about Diffrences in speaker size would be very much appreciated.

Please end this confusion once and for all and settle all the rumors.

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[jmanpc 5,000+ posts]

An 8 or a 10 can't 'get low' because it can't move enough air to have the impact of a 15 or 18 when it 'gets low'. I mean, they can play that low just fine, but it doesnt have the impact of a larger sub.

From my experience, a 15 can be just as punchy as a 10.

 

[Flipx99 5,000+ posts]

IMO, I go for what I want out of my install. I can't fit 18s, so even if they were better, it wouldn't work for me.

I like 12s and 8s. They are the best to me because they work best for my installs.

 

[xpl0it 10+ year member]

Smaller subs will be able to move quicker, simple physics. Larger subs have larger throw so they obviously will respond better to slower movement (low end bass). The sub size is just as important as box size/port. You can't really argue about subs without the relationship to the enclosure. Enclosures are just as important if not even more when looking for what kind of bass you want. 12's are great for all around response. So really, you should be thinking about the enclosure before you go for the sub. Look at space and see what you can use box wise, then think about what kind of subs you want.

 

[PendulousThread 10+ year member]

so the only diffrence (not install diffrences) is that a samller sub doesnt have as much impact as a larger one?

 

[DBfan187 5,000+ posts]

//content.invisioncic.com/y282845/emoticons/hilarious.gif.02a037aad04aa96f19982b298a3d70a8.gif

 

[PendulousThread 10+ year member]

ive been told many a time that larger subs do not move slower than smaller ones this isnt true???

 

[Flipx99 5,000+ posts]

ive been told many a time that larger subs do not move slower than smaller ones this isnt true???

For a given frequency, it is my understanding woofer speed is the same, however the amount of air moved is different. There is a paper on it from Adire but it is difficult to understand with limited knowledge of subs.

 

[Flipx99 5,000+ posts]

Found the link:

http://www.adireaudio.com/Files/WooferSpeed.pdf

 

[PendulousThread 10+ year member]

I understand it thanks.

 

[audioholic 5,000+ posts]

Smaller subs will be able to move quicker, simple physics.

Wrong. Im tired of explaining this fallacy. For the love of god, just read this: http://www.adireaudio.com/Files/WooferSpeed.pdf

Larger subs have larger throw so they obviously will respond better to slower movement (low end bass).

Wrong again. Most models of subs use the same motor, hence the same 'throw' (excursion) from the 10" version to the 18" version. Kinda shoots a big hole right through the middle of your theory, huh? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
Larger subs do tends to have more low-end output than smaller subs, and it is from more air displaced, but its not from more excursion, its from more cone area while having the same excursion (as a smaller diameter version).

The sub size is just as important as box size/port.

Nope. Enclosure is MUCH more important. When I attended installer institute back in the early 90's, we built a 'subwoofer' enclosure for a 3" driver (TL iirc), it extended amazingly low. This was to teach us the importance of the enclosure. That's not to say the speaker isn't important to, but you place way too much empahsis on it over the enclosure for actual frequency response characteristics.

Enclosures are just as important if not even more when looking for what kind of bass you want. 12's are great for all around response.

Just when I was gonna agree with you, you had to throw in the generalization about 12" diameter subwoofers. Again, you place way too much emphasis on the diameter of the radiating surface in the subwoofer system.
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so the only diffrence (not install diffrences) is that a samller sub doesnt have as much impact as a larger one?

Let me break this down for you. The lower the frequency of the note being played, the more air needed to reproduce it at a given output level (loudness). So obviously the sub that moves less air will not be able to have as much authority at lower freqs as the one that moves more air. But, pair up two 8" subs and they will hit (basically) just as low as a single 10. An array of 8's in a wall would have the ability to extend very low with alot of authority, because together they would move alot of air. Anything else said about the difference in cone diamateres (including weight/inertia arguements) is just hot air, BS, or over-generalizations.

For a given frequency, it is my understanding woofer speed is the same, however the amount of air moved is different. There is a paper on it from Adire but it is difficult to understand with limited knowledge of subs.

For a given frequency, cone speed MUST be the same. Think about it, a frequency is merely cycles per second. So for a speaker to reproduce a 50hz note, it moves back and forth 50 times per second. If its slower than that, its no longer even playing a 50hz note.
One of the basic flaws in the theory that 'larger cones move slower due to weight' is, moving slower would not equate to a 'sloppy' response, it would literally alter the music, the woofer would be 'off key'. This obviously does not happen, yet another way to show the woofer speed theory holds no water.

If you have any questions on the Adire woofer speed paper (I linked to it above btw), ask away. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[bikinpunk 10+ year member]

One of the basic flaws in the theory that 'larger cones move slower due to weight' is, moving slower would not equate to a 'sloppy' response, it would literally alter the music, the woofer would be 'off key'. This obviously does not happen, yet another way to show the woofer speed theory holds no water.

I'm agreeing, yet asking to verify my thoughts on this:

If one's slower, the comparison is out the window since they are no longer playing the same frequency.

For example:

Playing a 40hz tone:

If A is moving 40 cycles/sec it's playing 40hz.

If B is moving slower than A, it is no longer playing 40hz and is playing something lower.

correct?

 

[audioholic 5,000+ posts]

I'm agreeing, yet asking to verify my thoughts on this:If one's slower, the comparison is out the window since they are no longer playing the same frequency.

For example:

Playing a 40hz tone:

If A is moving 40 cycles/sec it's playing 40hz.

If B is moving slower than A, it is no longer playing 40hz and is playing something lower.

correct?

Well, I dont want to over simplify. Cone speed will depend on 2 things: frequency of the material being played (its cycles per second) AND on the excursion its moving. I say this because if you compare different woofers, one with twice the excursion as the other... one will have to move twice as 'fast' to maintain the same number of cycles per second. Understand? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

But yes, when comparing the same sub (or two identical subs) playing 40hz, if one's cone were to 'slow down' while maintaining the same excursion, in effect it would be playing a lower frequency... because its moving something less than that 40 cycles per second (from your example).

Hope that explains it better for you. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Flipx99 5,000+ posts]

Ha ha...I was right AND posted a link. Thanks for validating my post.

I understand the premise, but not all the jargon and formulas.

 

[bikinpunk 10+ year member]

Well, I dont want to over simplify. Cone speed will depend on 2 things: frequency of the material being played (its cycles per second) AND on the excursion its moving. I say this because if you compare different woofers, one with twice the excursion as the other... one will have to move twice as 'fast' to maintain the same number of cycles per second. Understand? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
But yes, when comparing the same sub (or two identical subs) playing 40hz, if one's cone were to 'slow down' while maintaining the same excursion, in effect it would be playing a lower frequency... because its moving something less than that 40 cycles per second (from your example).

Hope that explains it better for you. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Gotcha'.

So, a subwoofer can indeed be "faster" at the same cycle/sec because we're talking the amount of time it takes to reach excursion...not the actual cycles.