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Thanks, guys... this is all very interesting. I'm learning from everyone's comments. I was able to put the driver in a cabinet and test it out. I tried running it as you would with a conventional one amp/2 speaker setup- left and right channel from amp feeding separate voice coils. And, I tried running the voice coils in series with a mono input and lastly I tried the running the voice coils in parallel with a mono input. I used the same amp (M1.0t mkII Opt 2) for each setup. Honestly, there was very little difference in sound quality. If I had to pick one setup over the other, I'd pick the conventional setup for a 2 channel amp feeding the separate voice coils. So, I think that's how I will setup the final configuration. I'll post pictures of my project once I get to finishing the cabinet....... that may be a while down the road. I've got lots of projects starting to back up on me, lol! Thanks again for all the help.

There's nothing to debate. You just compared opinions to actual science, and that's apples and oranges. Audio myths die hard, and DF as a basis for quality is one of the most prevalent myths there is.

Sorry for not replying sooner but I have been away. Judging by the links you have provided and your well referenced reply we can probably both agree that the topic of amplifier-loudspeaker interaction is very complicated and perhaps one of the least understood areas of audio. So its a great topic to debate on the forum. After reviewing your first reference which takes a position to debunk the connection between DF and controlling cone movement I may have a tendency to agree with you on that particular point. However that does not mean DF is unimportant to the perceived sound of a loudspeaker or subwoofer. The following is taken from the Wikipedia link you provided on DAMPING FACTOR: "John Atkinson and Stereophile have recognized the importance of amplifier damping factor, and have made the use of the simulated loudspeaker load a routine part of their measurements of amplifiers. It is clear from the various amplifier frequency response curves that low damping factor values result in significant changes in the frequency response of the amplifier in a number of frequency bands. This will result in broad levels of sound coloration that are highly likely to be audible. "the amplifier with the low damping factor is acting more like a graphic equalizer than is the amplifier with the moderate damping factor." "Some amplifier designers, such as Nelson Pass, (of Threshold) claim that loudspeakers can sound better with lower electrical damping, although this may be attributed to listener preference rather than technical merit." The fact that both Atkinson and Pass take up opposite positions on the DF issue seems to indicate that despite their differences they at least each believe it is very important to the sound produced by the amp-speaker combination. I too have heard the bass related difference they talk about between low damping factor and high damping factor amps. Tube and transistor amps have widely different DF characteristics (yes, among many other differing characteristics) . Although this may have nothing to do with the effectiveness of an amplifier to tightly control cone movement the DF related EQ coloration is nonetheless still present in the amplified signal and therefore audible to the listener. One might even go as far as to say that perhaps the 'graphic equalizer effects' or 'tone alteration' produced by low damping amps might tend to make the listener hear or perceive a less tight bass response than a high damping factor amp due to addition bass coloration peaks that are artificial and an artifact added to the original bass output in the low DF amp. Unless you have something else to add I'll respectfully stay with my original statement to Kurt ..." However, the damping factor of the amplifier may play a bigger role in the SW sound than the number of channels you drive it with."

Sorry - amplifier DF plays very little role in the response of a mechanical driver. The method of calculating DF (driver impedance/amp output impedance) has been debunked many times as a reliable statistic in determining the effectiveness of an amplifier to 'control cone movement'. There is almost no difference between a DF of 20 up to Infinity as far as the entire system is concerned (cable resistance, internal impedance, variable frequency impedance, imaginary resistance, etc). http://linea-research.co.uk/wp-content/uploads/LR Download Assets/Tech Docs/Damping factor debunked -01a.pdf https://en.wikipedia.org/wiki/Damping_factor It's also easy to 'fudge' an amp's rated damping factor with negative feedback, which can make the output impedance look vanishingly small, but in real world applications can cause significant distortions and non-linearities. Furthermore, it's typically desirable to drive a loudspeaker with a system that looks more like a current source (high output impedance) since the motor driver of a loudspeaker is an inductor, which responds well to current, not voltage - ergo 'the tube sound'. All this should help indicate how complex the relationship between amplifier and speaker really is. There just isn't any specs that will break it down so you know what amps should drive certain speakers. There's a general idea, but in no way can one simply rely on such things as 'high DF' to determine if a certain amplifier can effectively drive a certain configuration, or that by adjusting the DF somehow you can you expect a better response.