Some basics for the dumbheads, including me.
Fs – (free air) resonance frequency of driver (Hz)
– frequency at which the combination of the energy stored in the moving mass and suspension compliance is maximum, which results in maximum cone velocity
– usually it is less efficient to produce output frequencies below Fs
– input signals significantly below Fs can result in large excursions
– typical factory tolerance for Fs spec is ±15%
This is the correlation between efficiency and stored energy that I referred to.
A loudspeaker system (a woofer in a box) is usually more efficient above Fs.
Fs – (free air) resonance frequency of driver (Hz)
– frequency at which the combination of the energy stored in the moving mass and suspension compliance is maximum, which results in maximum cone velocity
– usually it is less efficient to produce output frequencies below Fs
– input signals significantly below Fs can result in large excursions
– typical factory tolerance for Fs spec is ±15%
This is the correlation between efficiency and stored energy that I referred to.
A loudspeaker system (a woofer in a box) is usually more efficient above Fs.
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Of course you can store energy, e.g. in a car battery, but that's a different thing. To trace energy stored in a loudspeaker driver, drive it with a short impulse and see how long it takes for the all moving parts to decay their motion. That is the energy stored in the driver - all in mechanical (and electromagnetical) resonances, including the vibrating modes of the cone, spider, etc. If there were no losses it would oscillate like that forever. All of that typically manifest iftself in the frequency response as a non-flatness (except what Earl mentioned - I never saw that in practice however).
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So you also see why sentence like "...That gave an extremely flat frequency response, but also a lot of energy storage." really makes no sense.
There's energy stored in the resonance, so the more pronaunced it is (the higher the total Q), the longer the decay. I'm not sure about the absolute amount of energy "stored" - that's not correlated in any way I think. That depends on other things about the driver.
There's energy stored in the resonance, so the more pronaunced it is (the higher the total Q), the longer the decay. I'm not sure about the absolute amount of energy "stored" - that's not correlated in any way I think. That depends on other things about the driver.
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WE TA-7331-A
I am not sure if this baffle was already mentioned. I heard it at High End fair in Munich two years ago and was very surprised about the good sound. Simply use a proper horn on top of this and you have enough bass for private purposes.
ElectraVolt: Western Electric TA-7331-A Baffle
I am not sure if this baffle was already mentioned. I heard it at High End fair in Munich two years ago and was very surprised about the good sound. Simply use a proper horn on top of this and you have enough bass for private purposes.
ElectraVolt: Western Electric TA-7331-A Baffle
Let me put it this way: let's suppose the fraction of energy stored is the highest at Fs, as stated:
"frequency at which the combination of the energy stored in the moving mass and suspension compliance is maximum".
Then below this point efficiency usally decreases and vice versa.
If that isn't a correlation (relation/connection/link) between the two of them, I don't know what is.
"frequency at which the combination of the energy stored in the moving mass and suspension compliance is maximum".
Then below this point efficiency usally decreases and vice versa.
If that isn't a correlation (relation/connection/link) between the two of them, I don't know what is.
If there is any hint of correlation in practice, I'd say that less efficient drivers tend to store more energy at the resonance because of the weaker electrical damping (lower Bl). But I wouldn't call it a correlation as there are other things involved. Or I don't follow. Are you just saying that below Fs the efficiency decreases? Yes, it does, but that can happen without any enery storage at all (like for Q < 0.5).
The ETF guys are (alsmost) exclusively dealing with high efficiency drivers/horns/systems.
On several occasions my brother played electronic (as well as other) music through the loudspeakers shown below, and commented:
"Sounds better than any club system, even the Funktion One install of the Berghain."
Funny, because the G.I.P. 9700 is only 1/3 of the price
The cut off frequency of the big radial horn is 120 Hz.
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However, you really need a big room to get the most out of the 9700 system. The owner of the setup in the picture purposely built the space around it.
This G.I.P. system includes a similar baffle as the Western Electric TA-7331-A in docali's link and is better suited to a medium sized room:
This G.I.P. system includes a similar baffle as the Western Electric TA-7331-A in docali's link and is better suited to a medium sized room:
The folks at G.I.P. likely had their reasons to leave those out. Their systems are inspired by WE, not necessarily identical/perfect clones.
The G.I.P. 555 driver is based on the WE-555 with some subtle mods. According to the people who've used both, the G.I.P. units measure and (therefore) sound better.
The G.I.P. 555 driver is based on the WE-555 with some subtle mods. According to the people who've used both, the G.I.P. units measure and (therefore) sound better.
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store verb
\ ˈstȯr \
stored; storing
Definition of store (Entry 1 of 3)
transitive verb
ACCUMULATE
resonant adjective
res·o·nant | \ ˈre-zə-nənt , ˈrez-nənt\
Definition of resonant
intensified
intensify verb
in·ten·si·fy | \ in-ˈten(t)-sə-ˌfī \
intensified; intensifying
Definition of intensify
transitive verb
to increase
accumulate verb
ac·cu·mu·late | \ ə-ˈkyü-m
ə-ˌlāt \accumulated; accumulating
Definition of accumulate
transitive verb
to increase
there was some discussion of using a round horn to match vertical directivity at XO with a round woofer, thus justifying use of round horn rather than elliptical. Here is an elegant, albeit more complex and larger, alternative. Now that may not have been one of the design constraints, but clearly this approach could be followed to achieve that.
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