I didn't mean this topic or any member in particular. I was just replying to the comment that it's odd for a member of the DIY forum to reject the usefulness of a frequency response measurement. It is weird, but it's far from the weirdest unscientific thing I've seen here.
most here put a lot of value on a flat FR, i surely do. i dont think a speaker is well designer if its not flat.
dont mis judge the entire community based on a couple of people opinion....
i think the right term is dynamism. Which is probably more related to the real bass performance from the big speakers vs smaller ones
maybe id love big inneficient speakers as well
the first thing that jump at me when comparing small vs big speakers is always the impact, the drama, the feeling of a orchestra is about to explode in the room.
big drivers are faster then smaller ones, generally.
“
What is "faster"? Can we define it as a technical quantity?
My definition of "fast" is BL (in N per A) divided by moving mass.
Say moving mass of 215g and a BL of 21.8N/A means 21.8 Kg/ms^2 / 0.215kG = 101ms^2 per Ampere.
So 1A will produce a momenung of 101ms^2 per Ampere in the voice coil.
Let's compare to a "High End" 5.25" Woofer. It has 5.7N/A and 13g. It indeed has 438ms^2 per Ampere. So 1 Ampere will accelerate the cone 4.3 times as much as the 18" Cone.
BUT, for a given SPL, the 5.25" woofer with 95 sqcm cone area has to move nearly 14 times as far compared the 18" with 1320 sqcm cone area.
So for a required 14 times increase in moved distance, we will have only a 4.3 times increase on acceleration.
So if take acceleration times cone area (in sqm) are we get a "speed factor".
101 * 0.132 = 13.332
438 * 0.0095 = 4.161
Conclusion, relative to the required movement the "slow" 18" Woofer can accelerate 3.2 times as fast.
Another technical quantity may be the total Q of the LF system and LF group delay.
Well, that is woofer diameter independent and only a question how you design the acoustic system.”
I think what you might be missing here is that for some of us, myself incuded, who are dealing with rather small rooms the mid and high end is far more important than the low end.
And so while we recognize that it is possible to have more base with large drivers we are very content with what we have, and don't wan't to make the investment in 15"-18" drivers. Not just due to the cost, but we really don't have a good place to put them. Or to possibly get them to sound as they should.
That doesn't mean we would never invest in them. But it's a somewhat complicated issue and just makes the decision a more difficult one.
While your calculation is probably correct, the conclusion is wrong. If both those woofers you describe has the same FR, the move equally fast. If by fast you mean "the time it takes the cone to reach its desired position" it shall be as fast as the input signal demands - no faster. The "speed", as you call it, required have to do with the signal steepness - steepness = frequency reproduced - higher frequency = steeper signal. So again, if 2 woofers have the same upper BW, they are equally fast.
It has benn said several times on the forum so nothing new. If I hear a person talking about "fast" or "speed", its a safe sign of rookie thinking. You dont say "faster", you say higher upper frequency limit.
//
The speed is the time needed to reach a distance.
At iso spl target between say a 5" and 15" : let say 95 dB spl at the same frequency. The 15" if my understanding is correct, due to its surface will need to move less far VS the 5" that will need to move more to push air to make the same spl at the same frequency.
You will hear both driver at the same time. But the littliest driver will have to reach the required greater distance at the same time as the big driver for the same spl. That means the little driver needs to move its cone faster that the big just due to the greater distance to reach the spl at the same moment!
They have equal tempo from a listening perception side. As said above, different perception may occur because different pattern radiation. I also surmise without being sure about that, bigger Sd means less off axis power response so less reflected acoustic sound that arrive delayed to the ears which could be translated as less clean, less dynamic, so less "speedy" feeling as you say ? Humm I do not know here, but for speed, sure that is the littliest driver that move faster for the same result than a bigger one.
At iso spl target between say a 5" and 15" : let say 95 dB spl at the same frequency. The 15" if my understanding is correct, due to its surface will need to move less far VS the 5" that will need to move more to push air to make the same spl at the same frequency.
You will hear both driver at the same time. But the littliest driver will have to reach the required greater distance at the same time as the big driver for the same spl. That means the little driver needs to move its cone faster that the big just due to the greater distance to reach the spl at the same moment!
They have equal tempo from a listening perception side. As said above, different perception may occur because different pattern radiation. I also surmise without being sure about that, bigger Sd means less off axis power response so less reflected acoustic sound that arrive delayed to the ears which could be translated as less clean, less dynamic, so less "speedy" feeling as you say ? Humm I do not know here, but for speed, sure that is the littliest driver that move faster for the same result than a bigger one.
Last edited:
Can you explain why this speaker sells very well for over $200k and has good reviews?
Must have terrible comb filtering and lobing issues.
https://www.audiogon.com/listings/l...-best-will-do-certified-w-warranty-full-range
No, I know.
yes, thats correct - same FR, same "speed". (Within the linear ranges of drivers)
//
TNT, you are talking about the wave length of the frequency while YNY is talking about the speed of the cone, this is not the same, see my post above.
At iso medium and constant medium speed (here air in a room) for illustration : 100 hz has always the same speed related to its wave length period But if we say a driver is faster : i.e. the driver (not the music), it is about its cone mvt and here for reaching the same frequency, the cone speed will be different according the distance the cone has to reach for a same spl ! If my understanding is correct.
At iso medium and constant medium speed (here air in a room) for illustration : 100 hz has always the same speed related to its wave length period But if we say a driver is faster : i.e. the driver (not the music), it is about its cone mvt and here for reaching the same frequency, the cone speed will be different according the distance the cone has to reach for a same spl ! If my understanding is correct.
Last edited:
So explain why https://www.diyaudio.com/community/...gns-why-go-for-3-way-then.391639/post-7167527 is not correct .
For me this is you that mix up the speed of a related frequency (its WL) and the speed of a medium pushing air VS another of a different size to reach this same frequency at iso spl ! The percieved frequency has for sure the same speed as it is related to the WL frequency.
Notice it is not a problem to me to be wrong as far I understand the mistake for the proper reasonment.
For me this is you that mix up the speed of a related frequency (its WL) and the speed of a medium pushing air VS another of a different size to reach this same frequency at iso spl ! The percieved frequency has for sure the same speed as it is related to the WL frequency.
Notice it is not a problem to me to be wrong as far I understand the mistake for the proper reasonment.
Last edited:
https://www.diyaudio.com/community/threads/18-sub-driver-recommendation.391290/page-2#post-7157595
https://www.diyaudio.com/community/...rease-sound-stage.382407/page-20#post-6941810
https://www.diyaudio.com/community/...-driver-parameters.389859/page-3#post-7113403
https://www.diyaudio.com/community/...ion-with-a-2-way.334757/page-434#post-6824946
https://www.diyaudio.com/community/...-go-for-3-way-then.391639/page-9#post-7167534
//
https://www.diyaudio.com/community/...rease-sound-stage.382407/page-20#post-6941810
https://www.diyaudio.com/community/...-driver-parameters.389859/page-3#post-7113403
https://www.diyaudio.com/community/...ion-with-a-2-way.334757/page-434#post-6824946
https://www.diyaudio.com/community/...-go-for-3-way-then.391639/page-9#post-7167534
//
??? your sentenc has no sense imho, at least it demonstrates nothing.
You mean a 5" cone moves the same distance than a 15" cone to reach the same spl at the same frequency ? (because that same distance is the condition for us to have the same speed you are reffering to)
In real life : the 5" has to move for instance twice more distance to reach the same spl you will hear at the same moment ! It simply means it has to reach this distance at the same time (moment) than the 15" that moves twice less distance cause its bigger surface. And how you do to make the same time to cross twice the distance ? You simply need to move twice faster, that is what is the speed ! Simply as that !
If we talk about the speed of the cone, that is related to that for a spl targett. Speed is the distance divided by time. And of course for YNY it has nothing to see with the speed perception, or it is out of phase or group delay which is something else not related to the speed of the cone but the filter.
Hummm, better to see Rick and Morty on Netflix !
You mean a 5" cone moves the same distance than a 15" cone to reach the same spl at the same frequency ? (because that same distance is the condition for us to have the same speed you are reffering to)
In real life : the 5" has to move for instance twice more distance to reach the same spl you will hear at the same moment ! It simply means it has to reach this distance at the same time (moment) than the 15" that moves twice less distance cause its bigger surface. And how you do to make the same time to cross twice the distance ? You simply need to move twice faster, that is what is the speed ! Simply as that !
If we talk about the speed of the cone, that is related to that for a spl targett. Speed is the distance divided by time. And of course for YNY it has nothing to see with the speed perception, or it is out of phase or group delay which is something else not related to the speed of the cone but the filter.
Hummm, better to see Rick and Morty on Netflix !
Last edited:
all the cited example relate to bass speed
i was not only talking about bass speed.
high efficiency speaker system sounds fast, top to bottom. I hear this from big 2 ways with horns and a 15", wideband drivers, HE big 3 way systems, ect
in your opinion, their is not such thing as speed differences when comparing a wideband 95db 8" vs a 4 way 85 db efficient speaker?
Last edited: