Are 8's the new 12's?

[80INCHES 5,000+ posts]

hmmm i know i mentioned vas and qts as taking part in this whole discussion

80

 

[CAMSHAFT 10+ year member]

When and were?


Jon

????

 

[ibanender 10+ year member]

"2. Small Signal Parameters
The three parameters that primarily determine the frequency response

of a loudspeaker are compliance, free-air resonance, and Q.

The compliance, Vas, is a measure of the overall stiffness of the

cone, surround (the part the attaches to front of the cone), and

spider (the part that attaches to the rear of the cone). It is

specified as the volume of air having the same compliance as the

driver. A small number corresponds to a small volume of air, which is

stiffer than a larger volume of air. Thus, compliance and stiffness

are inversely proportional. Optimum enclosure volume is proportional

to Vas.

Free-air resonance, Fs, is the resonant frequency of the driver's

voice coil impedance with the driver suspended in free air (no

enclosure). The -3 dB frequency (F3) of an enclosure is proportional

to Fs.

The Q, Qts, is a measure of the sharpness of the driver's free-air

resonance. It is defined as (Fh-Fl)/Fs, where Fh and Fl are the upper

and lower -3 dB points of the driver's voice coil impedance in free

air. Optimum enclosure volume is related to Qts but is not directly

proportional. It is accurate to say that the volume gets larger as

Qts gets larger. Likewise, F3 gets smaller as Qts gets larger, and

for the sealed box enclosure, F3 is inversely proportional to Qts." - LOUDSPEAKERS PRIMER - http://www.rdrop.com/~billmc/spkr.txt

And, I "aprently" dont understand the relationship? You aparently dont understand the english language very well. You still continue to try to beat on me for 1) spreading false info (that I have a reference to back up) and 2) acting as if Im some expert here, when Ive never said anything to that effect, and said (repeatedly) just the opposite. Aparently you have one serious hard-on for putting me down here.

And I liked the part where you say I keep making myself look bad. Hello, Ive been asking you to explain for a page and a half now. Do you think I care if people know I dont know everything about this subject? If so, please refer back a page or two when I stated, clearly, that I do not. The continuance on your part to try to pile on the insults isn't making me look any worse here, only the guy doing it.

"You then have an endless cycle of people saying they want low bass so they have to buy 15's to achieve it."

And for the very last time, I never once said you must have a larger sub to acheive low bass. Not one time. Seriously, Im trying to remain mature here, but Im finding it hard to when you talk down to me like this, and yet STILL cant get that extremely simple concept thru your head. Please try harder, thanks.

OK, you have 1 internet source that says that. Go build a few things, test it in a real world application and get back to me on that. Everything I know is from physically doing it, not what somebody told me or I read somewhere. There are A LOT of reference materials written 40 years ago that were true then, but with modern technology do not apply anymore.

You've been asking me to explain for the last page and a half, but I have been explaining for the last 5 pages.

You keep saying a larger cone has a lower Fs, which in turn has a lower F3, which means the response is lower. If the response is lower, it plays lower. So just drug out the long way of saying 15's play lower than 8's. What exactly is it that you are arguing anyway? It looks like you keep changing your mind on what you have been saying. It seems like it started with 8's don't play low and you've migrated through a few things all the way down to the F3 of a box is the point where you pick up chicks because your Fs hangs low.

 

[ibanender 10+ year member]

hmmm i know i mentioned vas and qts as taking part in this whole discussion
80

You did, a few pages back, like I said with all the suspension stuff a few pages back. Just give him some time to catch up, maybe he'll get it around page 16.

 

[audioholic 5,000+ posts]

You keep saying a larger cone has a lower Fs, which in turn has a lower F3, which means the response is lower. If the response is lower, it plays lower. So just drug out the long way of saying 15's play lower than 8's. What exactly is it that you are arguing anyway? It looks like you keep changing your mind on what you have been saying. It seems like it started with 8's don't play low and you've migrated through a few things all the way down to the F3 of a box is the point where you pick up chicks because your Fs hangs low.

I do not debate with people smoking crack. Call me crazy, that's a personal rule. Therefore, I will point out your BS one last time, then you are free to spew it forth from now until this thread dies... without me.

"So just drug out the long way of saying 15's play lower than 8's."

Maybe if I type it slowly, you'll understand it better?.... I was refering to the Fs difference in same model subs. You are the one extrapolating that out to me saying 8's dont play as low as 15's in general. Put the pipe down, and think about it. And 'long way of saying' is just a metaphor for 'Im putting these words in your mouth'. Am I getting thru to you yet? Hope so, cuz this is the last time I explain this to you.

"It looks like you keep changing your mind on what you have been saying."

So Ive always wondered, how does crack cocaine and beer mix... well? Its me making the personal assumption about you this time, your current stoned state of mind aparently. Yes, Ive just changed my mind over and over in this thread, which of course is fully backed up by comments Ive made throughout the thread, like: "How am I backtracking one bit? Let me point out wht I first typed:" and "I stated it previously, aparently you missed it." Not to mention me, more than once, having to restate my initial comments so they would no longer be misconstrued by you. Now here you are, accusing me of changing my story all the time. Even one or two other people have stated they understood my point, and that it hadn't changed. Let me refresh your very weak memory...

I don't think audioholic is saying 8's can't play low. He never said every 15 will get lower then every 8..

Even a bystander tells you the same thing Ive told you, over and over, and you are still accusing me of saying this, even in your latest post, another page after YET ANOTHER PERSON pointed it out to you? Changing my story? LMAO! Seriously, you really made me laugh with that logic.

It seems like it started with 8's don't play low and you've migrated through a few things all the way down to the F3 of a box is the point where you pick up chicks because your Fs hangs low.

Yes, that's exactly what Ive been saying, all along..... 8's just dont get low cuz they are teenie tiny small and **** all kinds of hairy ***. You really are great at following a person's logic. Seriously, you really nailed it.
Maybe by page 16 YOU will finally figure out what Im saying, and what Im not. I wont be there, however.

OK, you have 1 internet source that says that. Go build a few things, test it in a real world application and get back to me on that. Everything I know is from physically doing it, not what somebody told me or I read somewhere. There are A LOT of reference materials written 40 years ago that were true then, but with modern technology do not apply anymore.

The date on that source is 1999 not 1966, oh knowledgeable one.

 

[kballa422 10+ year member]

Ok, so let me get this straight, you (ibanender) are saying that a larger cone size has nothing to do with a lower Fs? And that by adding moving mass you will lower the Fs? I know it depends on a lot of other things as well, basically the entire design of the driver, but wouldn't having a large cone increase the amount of moving mass, thus lowering the Fs? I may be wrong but that just seems to make since to me. And remember, this debate is based on this...we are comparing the EXACT SAME MODEL SUB.

I know there are other factors, but if you look at the same model sub, and look at the 8 vs 10 vs 12 vs 15, it always seems the Fs goes lower as the sub gets bigger, whether by a little or a lot, and while it may depend on several factors, all audioholic is saying, is that cone size is ONE of the factors. He is arguing the statement that Cone Size has NOTHING to do with a lower Fs.

And if you still argue this, and defend that statement, that cone size has nothing to do with Fs, and state that adding moving mass effects the Fs, then I ask you, does increasing the cone size not in effect increase the moving mass?

 

[T3mpest 10+ year member]

I brought this up on page 3 //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif Bigger cone has more mass, hence lower resonance frequency, meaning it will potentially play lower. No woofer is going to have any real output below FS, just doesn't happen. Even when you use lots of smaller woofers to mimic the same cone area, the large drop in F/R they will all exhibit at F/S will inhibit their response down low. That doesn't mean 8's can't play low, but it is an inherent strike against them, all things equal. Go physics 101?

 

[GeeTEye 10+ year member]

I think it comes down to one thing when comparing apples to apples. Take your DD8" and a DD12" and see what has more AUTHORITY on the low end. Or an ID8" vs an ID12". I belive an 8 can drop as low as a 12 or even a 15 (within the same company, you guys are comparing apples to oranges) but will not have the "grunt" that a larger woofer will have. How many people do you see running a single 8". Not many... How about a single 10" many...and a single 12 loooots of people. If there was no difference there would be no point in buying a 15 or 18" driver.

 

[ibanender 10+ year member]

I do not debate with people smoking crack. Call me crazy, that's a personal rule. Therefore, I will point out your BS one last time, then you are free to spew it forth from now until this thread dies... without me.
"So just drug out the long way of saying 15's play lower than 8's."

Maybe if I type it slowly, you'll understand it better?.... I was refering to the Fs difference in same model subs. You are the one extrapolating that out to me saying 8's dont play as low as 15's in general. Put the pipe down, and think about it. And 'long way of saying' is just a metaphor for 'Im putting these words in your mouth'. Am I getting thru to you yet? Hope so, cuz this is the last time I explain this to you.

"It looks like you keep changing your mind on what you have been saying."

So Ive always wondered, how does crack cocaine and beer mix... well? Its me making the personal assumption about you this time, your current stoned state of mind aparently. Yes, Ive just changed my mind over and over in this thread, which of course is fully backed up by comments Ive made throughout the thread, like: "How am I backtracking one bit? Let me point out wht I first typed:" and "I stated it previously, aparently you missed it." Not to mention me, more than once, having to restate my initial comments so they would no longer be misconstrued by you. Now here you are, accusing me of changing my story all the time. Even one or two other people have stated they understood my point, and that it hadn't changed. Let me refresh your very weak memory...

Even a bystander tells you the same thing Ive told you, over and over, and you are still accusing me of saying this, even in your latest post, another page after YET ANOTHER PERSON pointed it out to you? Changing my story? LMAO! Seriously, you really made me laugh with that logic.

Yes, that's exactly what Ive been saying, all along..... 8's just dont get low cuz they are teenie tiny small and **** all kinds of hairy ***. You really are great at following a person's logic. Seriously, you really nailed it.

Maybe by page 16 YOU will finally figure out what Im saying, and what Im not. I wont be there, however.

The date on that source is 1999 not 1966, oh knowledgeable one.

You are comparing the "same model subs" then you posted your candidate for reasoning, when in the same model all the subs were different! THAT is the point I've been trying to make, just because its in the same line doesnt mean its the same design. They have different motors and suspension to support the use of a heavier cone because its bigger! THAT is why the Fs is lower, the mass is higher for the given suspension! The second you change ANYTHING other than the mass of the cone, your entire arguement is thrown out the window. Guess what? You WON'T find the same everything except cone on ANY line out there (except for a Funky Pup type deal, which I've seen once, had like a 20 oz motor on all of them). Have you taken apart every one of those subs in the same line to find it has the same exact suspension, coil, and motor?

Here is a direct quote from your first post on this thread:

Fs of a speaker is proportional to its cone size. 8's just wont have the same low end as a comparable larger sub.

Right there you said the 8" wont have the same low end as the 10, 12, or 15 when in fact I have shown you a line of subs from 8 to 12 that WILL in fact deliver the same low end.

Maybe your knowledgable source should go build an SPL vehicle and tell me the Fs of the sub determines the F3. Maybe in a perfect world where everybody uses sealed boxes with proper alignments he would have a point, but I know how it works when you build boxes outside of manufacturer spec. Besides, F3 changes based on the environment too, gonna argue that next?

 

[ibanender 10+ year member]

I think if given the choice, most people wouldn't filter out subsonic material, just because. Its only filtered if the system requires it. That inaudible shaking adds an amazing amount of depth to the deep bass notes, depth that would otherwise be missing. Subsonic filters filter out bass that would be too low for the system and would cause damage (usually for vented systems with high tuning).
There is no such thing as being able to run too deep in terms of musical performance. If I had a system that ran flat to 1hz, up to say 150db (//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif), Id be thrilled. Its tuning points, port gain points and unloading points that create a situation of 'too deep bass'. Limitations set by the stereo system, not the desired performance. If you are worried about that potential damage, run a sealed enclosure, or keep your tuning to 30hz or higher (approx) OR use a subsonic filter and that should never really be an issue in car audio.

Ok, so let me get this straight, you (ibanender) are saying that a larger cone size has nothing to do with a lower Fs? And that by adding moving mass you will lower the Fs? I know it depends on a lot of other things as well, basically the entire design of the driver, but wouldn't having a large cone increase the amount of moving mass, thus lowering the Fs? I may be wrong but that just seems to make since to me. And remember, this debate is based on this...we are comparing the EXACT SAME MODEL SUB.
I know there are other factors, but if you look at the same model sub, and look at the 8 vs 10 vs 12 vs 15, it always seems the Fs goes lower as the sub gets bigger, whether by a little or a lot, and while it may depend on several factors, all audioholic is saying, is that cone size is ONE of the factors. He is arguing the statement that Cone Size has NOTHING to do with a lower Fs.

And if you still argue this, and defend that statement, that cone size has nothing to do with Fs, and state that adding moving mass effects the Fs, then I ask you, does increasing the cone size not in effect increase the moving mass?

Yes, I am saying a larger cone has nothing to do with the Fs. I'm saying the added mass has to do with the Fs going down. If you use the same material to do a larger cone, yes, it will add mass. But, that doesn't mean it got lower because the cone got bigger. If you take a driver and add weight to it, the Fs will drop. When you break in a sub, the Fs drops because the suspension got looser, which leads to my other point..... you can control the Fs by changing the suspension. So, to recap that, the Fs is dependant on the suspension and the moving mass, working together.

 

[ibanender 10+ year member]

I brought this up on page 3 //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif Bigger cone has more mass, hence lower resonance frequency, meaning it will potentially play lower. No woofer is going to have any real output below FS, just doesn't happen. Even when you use lots of smaller woofers to mimic the same cone area, the large drop in F/R they will all exhibit at F/S will inhibit their response down low. That doesn't mean 8's can't play low, but it is an inherent strike against them, all things equal. Go physics 101?

That is exactly right, assuming the designer of the sub is a moron and used all the same parts on all the models. Moreso than not you need to change the suspension when you double the mass between a 10 and 15 (at least, any good design would) so that doesn't make all things equal. Yes a bigger cone will have more mass, but its a huge generalization to say it WILL have a lower Fs when the design could change that.

You CAN have real output below Fs, its box dependant. Go listen to a Wave Radio.

 

[ibanender 10+ year member]

I think it comes down to one thing when comparing apples to apples. Take your DD8" and a DD12" and see what has more AUTHORITY on the low end. Or an ID8" vs an ID12". I belive an 8 can drop as low as a 12 or even a 15 (within the same company, you guys are comparing apples to oranges) but will not have the "grunt" that a larger woofer will have. How many people do you see running a single 8". Not many... How about a single 10" many...and a single 12 loooots of people. If there was no difference there would be no point in buying a 15 or 18" driver.

You are describing greater SPL, not response. Yes, more cone area is more likely to be louder as it displaces more air. However, the amount of air displacement is not a direct relation to how well it can reproduce a given frequency.

 

[CBFryman2 5,000+ posts]

I have a box for a single RE8 which I used daily for a while, played 25 hz just fine, peaked 32 hz in my car, and metered low 130's. That was enough for me to drive down the highway with windows down and be comfortable listening to it. Displacement isn't everything, but it helps.

Infrabass is 20Hz and down. And that RE 8 isnt pushing 130+ at 25Hz.

 

[CBFryman2 5,000+ posts]

I brought this up on page 3 //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif Bigger cone has more mass, hence lower resonance frequency, meaning it will potentially play lower. No woofer is going to have any real output below FS, just doesn't happen. Even when you use lots of smaller woofers to mimic the same cone area, the large drop in F/R they will all exhibit at F/S will inhibit their response down low. That doesn't mean 8's can't play low, but it is an inherent strike against them, all things equal. Go physics 101?

The Ava 18 has an Fs of 16Hz but it played 11Hz quite nicely for the short time it was doing HT duty. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[CBFryman2 5,000+ posts]

//content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif The Fs discussion is going in 'round and 'round in circles.//content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif