Funny thing Atmasphere: I've got that very paper saved on my computer. I've never liked negative feedback loops, probably what endeared me to David Hafler(his early ideas). I wondered if there was a connection between your name in here and the OTLs. The lack of a hyphen threw me(not so hard to do at my age). |
I'd bet the farm that those rooms utilized speakers of high efficiency and extremely low mass. Can you be more specific(amps/speakers)? There are a lot of designs out there that cater to the SET lovers for instance. Speakers that(by design) don't require a lot of power or damping factor. |
Audiokinesis- It's been a few years(like maybe 26) since anyone threw any Thiele-Small parameters at me, so I'm still picking up the pieces of my shattered brain here! From what you're describing: I'm going to guess the woofers are about 8" based on the Vas? If that's so: with a fairly high mechanical(11.69) and electrical(.35) system loss, they sound like they might have a relatively stiff compliance. The moving mass isn't all that high, so I'm thinking a fairly short throw(or single/flat wound) voice coil. If I'm all wet here, I'm certain you'll let me know. I don't expect any mercy!! |
Damping factor is is an amplifier's ability to control a woofer's motion after the drive signal has ceased. For example: if you drive a loudspeaker with a bass drum whack, the woofer's inertia and resonance in the enclosure will cause it to keep moving after the signal has died away. a This is a form of distortion that alters the music signal's dynamic envelope. The diaphragm of the Maggie is so light, and it's excursion so short(because of it's surface area) that the damping factor of your amp is virtually a moot point. The MMg's are only rated down to 50hz anyway(they're already rolling off at 80hz). Bottom line: Don't buy an amp to go with your Maggies based on damping factor. I'm using a Hafler TransNova 9505(255wpc) to drive my subs because of it's high damping factor(1000) and fast slew rate(150v/ms). Not an expensive amp at all(for high power and damping factor). BUT- I love tubes for my Maggie mains, and my Cary SLM-100s do a wonderful job. I've driven the Maggies full range with the Carys(and the Hafler for the heck of it) and they don't sound bad at all. Nothing beats the dyanamic range and transparency I get by bi-amping though. One more thing- Damping factor is related to the amplifier's output impedance. The lower the output inpedance, the higher the damping factor. The impedance of the cable between the speaker and amp decreases the effective damping factor of your amp. Keep you speaker cables short. |
While Back EMF is not completely irrelevant in this discussion, I didn't feel it warranted inclusion in the definition. For a better understanding of "damping factor", see these: (http://en.wikipedia.org/wiki/Damping_factor) Particularly pg 1, para 2,3 / pg 4, para 1 (http://www.classic-audio.com/marantz/mdampingfactor.html) Notice how often the word, "control" is used. Tube amps almost invariably have low damping factors. To say that Maggies need a high one, but that they sound best with tube amps is contradictory. Here's an interesting little article on the MMg's you may enjoy Hlgoh: (http://www.enjoythemusic.com/magazine/viewpoint/1199/donibbles.htm) |
It's interesting how those three different URLs came out with the same "wikipedia" addy in the post! Hlgoh- The main point is: Don't be confused by peoples' opinions. Most only have those and not much in the way of truth. Do the research, and make decisions based on facts. If you want truth in your music reproduction: Listen to/get familiar with a lot of live music(amplified AND acoustic), and base the judgement of your system's reproduction on that. Enjoy your listening!!! |
Atmasphere- The URLs that I mentioned above contain sites and papers written by engineers in the fields of audio and electronics. Are we to believe that their understanding of damping factor as it relates to speaker control is wrong,and you are right? |
Atmasphere- I'm re-reading your posts in these forums and trying to get a handle on your resistance to the idea of damping factor and speaker control. In another thread you advised the poster to avoid his "very long" speaker wires because his system would be negatively affected. What is your understanding of the effect that long cable would have if not raising the impedance of the amp/speaker interface, thereby lower the damping factor? Perhaps our semantics disagree? |
Atmasphere- I've based my belief in my understanding of electro-magnetic fuction and Newtonian physics. Inertia= When a body is in motion, it tends to stay in motion unless acted upon by an outside force. Yes- the music signal from the amp is driving the speaker(electro-magnetically). While this speaker is going through the motions of reproducing sound, it's mass is also trying to continue to move in the last direction(large transient) it was told to go by the amp(inertia). Of course- the higher the mass, the greater the inertia. The amp's ability to counteract this tendancy determines how faithfully the signal is reproduced. The effects of back EMF(and, perhaps, quantum physics) not withstanding- Is there something flawed, or mythological to this? If I am wrong(unlike some), I like to be corrected. Truth is more important to me than holding stubbornly on to a misconception. Please- enlighten me. |
Not exactly INefficient though, are they? So tell me: Were you, by any chance, using any kind of auto-xformer between the OTLs and your speakers? Gotta keep digging for factors here before I give up any ground! |
