Drubin: One set of my F's are "smoked" and awaiting a "full tilt" driver rebuild as per Bill at Millersound's suggestions. The other set is packed up. I am currently down to using what was primarily my HT system for both music and movies now. After relocating, i hope to have everything up and running, but i'll have to install a new AC system. My latest purchase ( 450 lb iso transformer / voltage regulation / surge suppression system ) should be here next week or so for that house. Only problem is, i don't know where i'm moving to as of yet. I may end up becoming a Hoosier and moving out of the "Land of Lincoln" if things keep going the way they are here. Illinois is becoming more and more of a "police state" as each day goes by.
Viridian: I hear what you are saying about each individual "layer" of material within the F and / or A, but this is completely different than how a whizzer cone works. The whizzer cone has a completely separate level of output / radiation pattern / frequency response than the main cone. On the other hand, the segmented Walsh design uses multiple types of material that pass signal from one into the other. If any one of the segments didn't pass signal into the other in a relatively uniform manner, you would end up with a loss of surface area. When you lose surface area, you end up with the associated reduction in low frequency extension. As anyone that has ever had a decent running pair of F's or A's know, weighty bass is definitely not their problem.
As to the Threshold 400A that you had, i looked up my notes on this amp. As most of you know, i'm a pretty vocal supporter of Nelson Pass designs, so what i have to say about this amp may come as somewhat of a shock.
First of all, the 400A is definitely not a stable amp. That is, it changes frequency response / transient response / distortion characteristics as impedance varies does so to a pretty noticeable degree. Sonically, the bass is solid so long as the amp isn't pushed. Once you start to throttle the amp, the bass gets soggier. This has to do with the lack of power supply reserve ( not enough filter capacitance ). While the warmth region and lower midrange are pretty decent, as frequency climbs, the upper mids and treble regions were noticeably forward and bright. This tends to highlight any type of lean recordings, exacerbating the problem. With most SS preamps, this amp would tend to introduce a very noticeable sibilance and glare problem.
Once into the top octave, the treble response fell off sharply. This was not as noticeable as one would think though due to the high frequency emphasis just below this point. A definite lack of brass shimmer to cymbals with more of a pronounced "raw & steely" sound.
Due to the increased upper midrange / treble output, transients seemed to be "in your face". The harmonic structure seemed slightly disjointed because of the lack of balance between the lows and highs.
Much of this could have been DRASTICALLY improved by working on and improving the power supply. After all, everything that the amp is capable of ( or doesn't do well ) starts in the power supply. This is why so many aftermarket modifications center around cleaning up / stiffening ( increased reserve ) / improving speed in the power supply of gear. If you've read any of the overly long AC based threads that i've posted, i've commented time and time again about how important the proper design of the power supply is.
As a side note, Nelson Pass has an article about how important the power supply is on his website. As to the Dayton-Wright's, Nelson also used these speakers to test various loudspeaker cabling on. He mentions these speakers in another article on his website, as they used to send some amps into convulsions. Using such a reactive / high demand speaker provided an excellent test bed to see how an amplifier would respond to changes in the load that it saw via altering the speaker cables & their electrical characteristics. As mentioned in that article, some cables allowed the amp to drive these speakers with no problems whereas other cables caused the amp to shut down. As such, there's an obvious audible and measurable difference there i.e. sound from the speakers with some cables and no sound with other cables : )
As far as ribs go, i'm trying to cut down on eating meat. When it comes to good barbecue though, i don't know how i could turn down either beef or pork. That is, until i get serious about my health and dining habits. My midsection is starting to protrude and as hot as it gets in the summer, i'll only be miserable if i don't lose some weight. Either that or convert some of that "mid section speed bump" into muscle on other parts of my body. Can anyone else relate??? : ) Sean
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Viridian: I hear what you are saying about each individual "layer" of material within the F and / or A, but this is completely different than how a whizzer cone works. The whizzer cone has a completely separate level of output / radiation pattern / frequency response than the main cone. On the other hand, the segmented Walsh design uses multiple types of material that pass signal from one into the other. If any one of the segments didn't pass signal into the other in a relatively uniform manner, you would end up with a loss of surface area. When you lose surface area, you end up with the associated reduction in low frequency extension. As anyone that has ever had a decent running pair of F's or A's know, weighty bass is definitely not their problem.
As to the Threshold 400A that you had, i looked up my notes on this amp. As most of you know, i'm a pretty vocal supporter of Nelson Pass designs, so what i have to say about this amp may come as somewhat of a shock.
First of all, the 400A is definitely not a stable amp. That is, it changes frequency response / transient response / distortion characteristics as impedance varies does so to a pretty noticeable degree. Sonically, the bass is solid so long as the amp isn't pushed. Once you start to throttle the amp, the bass gets soggier. This has to do with the lack of power supply reserve ( not enough filter capacitance ). While the warmth region and lower midrange are pretty decent, as frequency climbs, the upper mids and treble regions were noticeably forward and bright. This tends to highlight any type of lean recordings, exacerbating the problem. With most SS preamps, this amp would tend to introduce a very noticeable sibilance and glare problem.
Once into the top octave, the treble response fell off sharply. This was not as noticeable as one would think though due to the high frequency emphasis just below this point. A definite lack of brass shimmer to cymbals with more of a pronounced "raw & steely" sound.
Due to the increased upper midrange / treble output, transients seemed to be "in your face". The harmonic structure seemed slightly disjointed because of the lack of balance between the lows and highs.
Much of this could have been DRASTICALLY improved by working on and improving the power supply. After all, everything that the amp is capable of ( or doesn't do well ) starts in the power supply. This is why so many aftermarket modifications center around cleaning up / stiffening ( increased reserve ) / improving speed in the power supply of gear. If you've read any of the overly long AC based threads that i've posted, i've commented time and time again about how important the proper design of the power supply is.
As a side note, Nelson Pass has an article about how important the power supply is on his website. As to the Dayton-Wright's, Nelson also used these speakers to test various loudspeaker cabling on. He mentions these speakers in another article on his website, as they used to send some amps into convulsions. Using such a reactive / high demand speaker provided an excellent test bed to see how an amplifier would respond to changes in the load that it saw via altering the speaker cables & their electrical characteristics. As mentioned in that article, some cables allowed the amp to drive these speakers with no problems whereas other cables caused the amp to shut down. As such, there's an obvious audible and measurable difference there i.e. sound from the speakers with some cables and no sound with other cables : )
As far as ribs go, i'm trying to cut down on eating meat. When it comes to good barbecue though, i don't know how i could turn down either beef or pork. That is, until i get serious about my health and dining habits. My midsection is starting to protrude and as hot as it gets in the summer, i'll only be miserable if i don't lose some weight. Either that or convert some of that "mid section speed bump" into muscle on other parts of my body. Can anyone else relate??? : ) Sean
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