VictoriaGuy said:
Actually this is the point where a driver has the most output for a given power input. Most graphs are done with a constant voltage amplifier, and the power output is inversly proportional to the impedance (ie the measurement technique has a built in EQ adjustment to keep the FR flat). Drive the same speaker with a constant current amplifier and that big FR peak reveals itself.
This resonance is special as well as it marks the transition from one kind of operation to another and we use this to our advantage by designing boxes around this information.
dave
". . .Actually this is the point where a driver has the most output for a given power input. . . . "
Which is why I prefer drivers that have well behaved impedence with small impedence peak at Fs.
While some may consider the driver with a high impedence peak at Fs to be a good thing (less input but equal or more output) , I believe there is no thing as a free lunch.
That huge impedence peak (some drivers are over 100 ohms at Fs) just means (to me) that the driver will be less controlled and is basically excited to the point of being out of control at the Fs. Poorly damped at Fs, which causes ringing/oscillation. No thanks.
While Morel doesn't make FR units, I am always on the lookout for drivers that have such well behaved impedence characteristics as they do.
I think the key is to use as many shorting devices as possible during motor design/construction, as this reduces the resonances of the motor , allowing for a more linear impedence . This translates into better control and an easier load for the amplifier to drive.
The only downside I can see is that the use of shorting devices in the construction of the motor tends to reduce the efficiency .
Choose your poison.
After looking at those Lowther charts, I can only scratch my head and wonder why anyone would even consider using their drivers. Horrible impedence response, horrible frequency response, horrible frame/basket design , etc.
I didn't intend to insult anyone with this, sorry if that happened. I just DON'T get Lowthers .
..........................Blake
Which is why I prefer drivers that have well behaved impedence with small impedence peak at Fs.
While some may consider the driver with a high impedence peak at Fs to be a good thing (less input but equal or more output) , I believe there is no thing as a free lunch.
That huge impedence peak (some drivers are over 100 ohms at Fs) just means (to me) that the driver will be less controlled and is basically excited to the point of being out of control at the Fs. Poorly damped at Fs, which causes ringing/oscillation. No thanks.
While Morel doesn't make FR units, I am always on the lookout for drivers that have such well behaved impedence characteristics as they do.
I think the key is to use as many shorting devices as possible during motor design/construction, as this reduces the resonances of the motor , allowing for a more linear impedence . This translates into better control and an easier load for the amplifier to drive.
The only downside I can see is that the use of shorting devices in the construction of the motor tends to reduce the efficiency .
Choose your poison.
After looking at those Lowther charts, I can only scratch my head and wonder why anyone would even consider using their drivers. Horrible impedence response, horrible frequency response, horrible frame/basket design , etc.
I didn't intend to insult anyone with this, sorry if that happened. I just DON'T get Lowthers .
..........................Blake
VictoriaGuy said:
Look at any response where the impedance is shown also. There will be a corresponding blip in the response due to the phase inversion since each one represents a mechanical XO. Are they audible? Big ones are and can be as fatiguing as an electrical XO. Little ones can be too if they're up in our sibilance BW, so where modest cone treatments have the most effect.
GM
Cheers Greg. I'm ashamed to say I got a lump of Aberdeen Angus caught in my throat which blocked most of the airway for an hour or so.
Not something I'd care to repeat.Yeah, I'd take more numerous, smaller resonances too over a couple of large ones. Seeing Dave's overlays, the AN's don't come out badly in comparison to the Lowthers. TBH, I can't say I'm a fan of Lowthers generally. I've tried; I've failed. My mate Steve's EX4s with supporting woofers on OB are extremely impressive & it's always good fun to hear them for an evening, but I couldn't live with them. To each their own.
what about ....
now what about the 8inch modified fostex?
DECWARE Full Range Driver DFR-8. ... <-- check out the white paper link on that page ...
and its $300/pr .. cheaper than the $450/pr for the fostex ... alnico is a interesting bonus but i am trying to decide which way i should go first ... ?
now what about the 8inch modified fostex?
DECWARE Full Range Driver DFR-8. ... <-- check out the white paper link on that page ...
and its $300/pr .. cheaper than the $450/pr for the fostex ... alnico is a interesting bonus but i am trying to decide which way i should go first ... ?
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