Are 8's the new 12's?

[CBFryman2 5,000+ posts]

As I said you have never sat in my CRX //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif I'm sure Chevyaudio will this spring at upcoming shows and verify this...I'm wanting to hear his truck...and I know his will be impressive as well //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif I hate we are in the same competition class...but we seldom make the same shows anyway...As far as one note wonders...no one is even close to my street beat numbers same as bass race.....read my signature for how it works...30secs playing a store bought CD isn't a one hit wonder...You need to know a speaker before running your mouth about the unknown....I'm sure your speakers are decently loud...I'm just saying my two 10's can do the same...in a fraction of the room....

//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

Not only have I played with 3500 series but I highly doubt you are +- 3dB 30-60Hz.

 

[CBFryman2 5,000+ posts]

Mine's a one note wonder and it will still beat you in street beat or bass race, with a store bought CD. As a matter of fact, I've done bass boxing with it for 60 seconds on music. Moral of the story, you CAN have a one note wonder in bass race, as long you find a disc that plays your note, as I have.

And what he said.

the DJ Magic Mike CD that was banned from Bassrace is basically tones and music on top of a 50Hz tone....reall hard to to stay loud with that. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

 

[NoviceGuru]

also in the world of "subwoofer" i realise there are many different variables but a 8 still doesn't have the ability to play as low as a 18 with the same motor, power, etc.

 

[CBFryman2 5,000+ posts]

okay i don't want to cause any more debate but i agree that the larger the sub the lower it well play. my reasoning?
mother nature......

when a small power full airstream is moving you hear high pitch whislte sound.

a small area of air moving.

now when there is large stream of air moving (such as a storm) you hear a much deep pithched sound.

a large area of area moving.

no if the area of air being moved had NOTHING to do with it why would i not hear the same sound.

.....that my friends is as technical as i get

worst reasoning ever.

 

[NoviceGuru]

maybe true but can you explain why that happens if area of air being moved has nothing to do with it?

 

[NoviceGuru]

besides i made that post mostly because my odd humor thought it was funny

 

[audioholic 5,000+ posts]

The difference is small, and the difference is large. You just don't get it do you? It has nothing to do with the fact that one is an 8 and the other is a 15. I've already explained 3 times how the suspension is a huge factor in the Fs and how easily the Fs can be changed based on that alone.

Its funny you say Im not getting it, yet I am, and you aren't. Hello, different model subs compared, you can find all sorts of smaller subs that when compared to a different brand/model sub, exhibits the same (or similar) Fs and F3 results. Wow, newsflash. But uhm, that's beside what Ive said, all along. If you are gong to be condescending, at least be accurate.
And after all this, after you demanding I explain "WHY", and after I state I dont know why (only that the relationship exists), and specifically ask YOU to explain, you do not. Instead you say you've explained 3 times. You are stating suspension is a huge factor in Fs. Again hello, I already stated I know this. That does not explain the "WHY" that you were demanding from me earlier. So, if you are gonna badger me to do something, I should be able to expect you to be able to do it. Please, feel free to re-read my previous post where I stated I knew it was related to suspension compliance but didnt understand why suspension stiffness contributes to LFE, and answer the question. Otherwise, get off my back for not having done so.

I'm quoting everything you say in my response, don't even try that "things I didnt say" crap.

Oh, so you've quoted me in this thread said why Fs changes? You've quoted me stating 'moving mass' affects LFE? No, you haven't, and yet you continue to accuse me of saying these things. Then tell me Im the one not 'getting it' here. Until this trend ceases, I will continue to ask you (and anyone else) to stop placing words in my mouth I did not say.

My guess is you have little real world experience with a lot of subs, but do spend a lot of time looking at mocked up graphs. So, let me put this in terms you can understand.

What does your 'guess' on my background have to do with this discussion beyond you trying to attack me on some personal level now? You dont know me or my experience, dont presume to. Your little experiment with a 5.25 speaker in a T-line... I did the same experiment in the early 90's while attending installer institute. But yes, I really needed you and hoss to explain this to me, today, in this thread. //content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif Im not the brain dead noobit you keep trying to portray me as.
Why the hostility? Ive already stated I do not fully understand the relationship between Fs and LFE, yet instead of taking that opportunity to tell me/us, you instead chose to attack me in this manner. If this continues, I will not. Im not interested in some petty personal attackfest.

Go under Bass Box Pro, pick the RE RE8 and plot it using the "suggest" button on a sealed box. It will make a box with a Qtc of 0.707 (which is the "accepted" standard). The RE8 has an Fs of 22.8 hz. It will show an F3 point of 48.95 hz. Now plot an Image Dymanics ID15 D4v2 the same way. That is a 15" driver with a Fs of 21 hz (1 hz lower than the RE8 if you didnt catch on). It will show an F3 point of 49.09 hz. If cone size determines the F3 point, even with a Fs only 1 hz off, why does the 15 have an F3 point of 1 hz higher than the 8 which has an Fs of 1 hz lower?

Nice example, yet another one comparing different drivers. Again, I get it. //content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif Eventhough that is not the situation I have been talking about (Fs lowering as cone sizes increases on same model subs), I acknowledge the point you are making, and have been continually making for like 3 pages now. Are we clear yet? That still does not explain the "WHY" you have asked me to discuss. Now Im asking you, again.

 

[ibanender 10+ year member]

okay i don't want to cause any more debate but i agree that the larger the sub the lower it well play. my reasoning?
mother nature......

when a small power full airstream is moving you hear high pitch whislte sound.

a small area of air moving.

now when there is large stream of air moving (such as a storm) you hear a much deep pithched sound.

a large area of area moving.

no if the area of air being moved had NOTHING to do with it why would i not hear the same sound.

.....that my friends is as technical as i get

What air streams are you comparing? It seems like you are comparing different velocities of air, which is not air displacement. There is also no control in that example.

 

[ibanender 10+ year member]

also in the world of "subwoofer" i realise there are many different variables but a 8 still doesn't have the ability to play as low as a 18 with the same motor, power, etc.

No, the 8 is less likely to have the ability to play AS LOUD as the 18 given those conditions. You are talking about air displacement, not frequency response.

 

[ibanender 10+ year member]

Its funny you say Im not getting it, yet I am, and you aren't. Hello, different model subs compared, you can find all sorts of smaller subs that when compared to a different brand/model sub, exhibits the same (or similar) Fs and F3 results. Wow, newsflash. But uhm, that's beside what Ive said, all along. If you are gong to be condescending, at least be accurate.
And after all this, after you demanding I explain "WHY", and after I state I dont know why (only that the relationship exists), and specifically ask YOU to explain, you do not. Instead you say you've explained 3 times. You are stating suspension is a huge factor in Fs. Again hello, I already stated I know this. That does not explain the "WHY" that you were demanding from me earlier. So, if you are gonna badger me to do something, I should be able to expect you to be able to do it. Please, feel free to re-read my previous post where I stated I knew it was related to suspension compliance but didnt understand why suspension stiffness contributes to LFE, and answer the question. Otherwise, get off my back for not having done so.

Oh, so you've quoted me in this thread said why Fs changes? You've quoted me stating 'moving mass' affects LFE? No, you haven't, and yet you continue to accuse me of saying these things. Then tell me Im the one not 'getting it' here. Until this trend ceases, I will continue to ask you (and anyone else) to stop placing words in my mouth I did not say.

What does your 'guess' on my background have to do with this discussion beyond you trying to attack me on some personal level now? You dont know me or my experience, dont presume to. Your little experiment with a 5.25 speaker in a T-line... I did the same experiment in the early 90's while attending installer institute. But yes, I really needed you and hoss to explain this to me, today, in this thread. //content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif Im not the brain dead noobit you keep trying to portray me as.

Why the hostility? Ive already stated I do not fully understand the relationship between Fs and LFE, yet instead of taking that opportunity to tell me/us, you instead chose to attack me in this manner. If this continues, I will not. Im not interested in some petty personal attackfest.

Nice example, yet another one comparing different drivers. Again, I get it. //content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif Eventhough that is not the situation I have been talking about (Fs lowering as cone sizes increases on same model subs), I acknowledge the point you are making, and have been continually making for like 3 pages now. Are we clear yet? That still does not explain the "WHY" you have asked me to discuss. Now Im asking you, again.

Finally, you just said you didnt understand. If you don't understand why you see that relationship, then how can you preach it to people as fact?

I compared different subs because that is what you have been doing all along by making the generalization of 15's will play lower than 8's because the cone is bigger. Given the same line of drivers that use the motor and coil (which will probably require a 10 and 12 comparison) where the only variable is the cone size (which directly has a result of a higher MMS with a larger cone) the 12 will have a lower Fs. The reason being, the higher MMS. If you added weight to the 10" cone to equal the 12 MMS, you'd get the same Fs as the 12.

If you are going to try to generalize something, you have to play with 1 variable, not many. Why no response to getting the Fi subs with different spiders? Scared to admit you can add moving mass to the SAME WOOFER and the Fs go up?

Maybe if I dumb this down really far it will make sense to those who don't quite get it. Fs is the resonant frequency of the speaker. That is the most efficient and loudest frequency it will reproduce in no enclosure, and ironically also have the highest impedance rise. A number of things can change that result, but the most effective changes are the moving mass and the suspension tightness (which also has to do with Vas as mentioned before). You can demonstrate this to yourself by knocking on a small piece of metal, then on a larger piece of metal (presuming both are the same thickness, type of metal, etc). The larger piece will have a lower tone. That is a perfect example of changing ONLY mass.

 

[NoviceGuru]

What air streams are you comparing? It seems like you are comparing different velocities of air, which is not air displacement. There is also no control in that example.

okay, air from an air compressor. say you have 700psi with a pin size hole nozle. that would hurt your ears like hell. high pitched. now say you had 700psi coming out of a nozzle 4 times the size. the sound would be much low in pitch

 

[CBFryman2 5,000+ posts]

That has to do with bending air.

How low a sub plays is dictated by how much air it can displace. a 12" sub that can move 30mm one way and a 15" sub that can move 15mm one way displace about the same ammount of air and, therefor, can get equaly loud as low taking the enclosure out of the factor.

 

[helotaxi 5,000+ posts]

You are all arguing two different things. A larger sub will play the low freqs louder and will play ALL frequencies louder. That doesn't mean that the small sub can't play the lows. That general statement just can't be made. Volume is totally relative. Normalize the response curves to a reference for each driver and it's quite easy to find a small driver with a lower F3 than a large one. That the F3 at max SPL is 15dB lower that the larger driver is irrelevant. 8's can have usable output down to subaudible freqencies but since they move less air they won't have the same volume at that low freq. That can be compensated for with more drivers to move more air.

Low Fs also does not automatically equate to good low frequency extension. There's a lot more to it than that. Cone size and Mms are also only part of the factors determining Fs.

The long and the short is that being able to play flat down to 20hz is not a function of cone size. Being able to play loud at low frequencies (not the same as flat response) is a function of cone size.

 

[audioholic 5,000+ posts]

Finally, you just said you didnt understand. If you don't understand why you see that relationship, then how can you preach it to people as fact?

No, not finally. I stated it previously, aparently you missed it. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

How can I 'preach' it as fact? Are you saying the -3 dB frequency (F3) of an enclosure is NOT proportional to Fs?

If you are going to try to generalize something, you have to play with 1 variable, not many. Why no response to getting the Fi subs with different spiders? Scared to admit you can add moving mass to the SAME WOOFER and the Fs go up?

Scared of what, admitting I dont understand the relationship? //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif You just cant help trying to make me look bad, can you?

Maybe if I dumb this down really far it will make sense to those who don't quite get it. Fs is the resonant frequency of the speaker. That is the most efficient and loudest frequency it will reproduce in no enclosure, and ironically also have the highest impedance rise. A number of things can change that result, but the most effective changes are the moving mass and the suspension tightness (which also has to do with Vas as mentioned before). You can demonstrate this to yourself by knocking on a small piece of metal, then on a larger piece of metal (presuming both are the same thickness, type of metal, etc). The larger piece will have a lower tone. That is a perfect example of changing ONLY mass.

Dumb it down eh? Im sure those who read your words and learn from it will apreciate you calling them dumb, myself included. Guess what... I didn't know, as I said before. Now I understand better. Im sure others will too. Thats the good part. The sad part is, no matter how much Ive tried reasoning with you to calm down and act mature, you continue to insult. I may need to learn more in order to fully understand this topic, but I will... you sir, will always be an ***.

You are all arguing two different things. A larger sub will play the low freqs louder and will play ALL frequencies louder. That doesn't mean that the small sub can't play the lows. That general statement just can't be made. Volume is totally relative. Normalize the response curves to a reference for each driver and it's quite easy to find a small driver with a lower F3 than a large one. That the F3 at max SPL is 15dB lower that the larger driver is irrelevant. 8's can have usable output down to subaudible freqencies but since they move less air they won't have the same volume at that low freq. That can be compensated for with more drivers to move more air.
Low Fs also does not automatically equate to good low frequency extension. There's a lot more to it than that. Cone size and Mms are also only part of the factors determining Fs.

The long and the short is that being able to play flat down to 20hz is not a function of cone size. Being able to play loud at low frequencies (not the same as flat response) is a function of cone size.

Good info there, thanks helo. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[80INCHES 5,000+ posts]

Go under Bass Box Pro, pick the RE RE8 and plot it using the "suggest" button on a sealed box. It will make a box with a Qtc of 0.707 (which is the "accepted" standard). The RE8 has an Fs of 22.8 hz. It will show an F3 point of 48.95 hz. Now plot an Image Dymanics ID15 D4v2 the same way. That is a 15" driver with a Fs of 21 hz (1 hz lower than the RE8 if you didnt catch on). It will show an F3 point of 49.09 hz. If cone size determines the F3 point, even with a Fs only 1 hz off, why does the 15 have an F3 point of 1 hz higher than the 8 which has an Fs of 1 hz lower?

u never mentioned the size of the box each sub was in

the 8 could have been in a small sealed box and the 15 could have been in a small box as well

put them in real world applications and results will be different

80