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Looking to expand my knowledge re. impedance and control
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<blockquote data-quote="Ampdog" data-source="post: 51036" data-attributes="member: 144"><p>Oh dear ....</p><p></p><p>We must go right back to the beginning. Those twin 2-ohm coils always puzzled me in the past. I take it they are wound on the same form; bifilar or at least in some close vicinity. <em>Then connecting them in series - twice the number of windings - will yield 2(square) times 2 ohm, or 8 ohm each, not 4 ohm.</em> But the inductance is of quite a low Q, so back one goes to perhaps nearer 2 x 2 = 4 ohm. And the topology: Are they wound end-to-end, thus increasing Xmax? I would guess one on top of the other; but does someone know?</p><p></p><p>Back to your problem: As Frikkie hinted, there are many variables here, many of which would reflect in the impedance graph, which in turn could well be influenced by the room (and definitely smaller car interior) volume, particularly at low frequencies. It is almost certain that they will not 'see' the same external (acoustical) impedance. Further then, when connected in series, control over the pair becomes very different as these two different and varying impedances are now reflecting into each other - amp output impedance and cable resistance now being negligible.</p><p></p><p>As you see, intuitively the series version might well be worse ... but it is better! The mentioned 'worseness' might well be countered by easier amp drive as said. That for now; I must go; other contributions are sure to come. Interesting problem ...</p></blockquote><p></p>
[QUOTE="Ampdog, post: 51036, member: 144"] Oh dear .... We must go right back to the beginning. Those twin 2-ohm coils always puzzled me in the past. I take it they are wound on the same form; bifilar or at least in some close vicinity. [I]Then connecting them in series - twice the number of windings - will yield 2(square) times 2 ohm, or 8 ohm each, not 4 ohm.[/I] But the inductance is of quite a low Q, so back one goes to perhaps nearer 2 x 2 = 4 ohm. And the topology: Are they wound end-to-end, thus increasing Xmax? I would guess one on top of the other; but does someone know? Back to your problem: As Frikkie hinted, there are many variables here, many of which would reflect in the impedance graph, which in turn could well be influenced by the room (and definitely smaller car interior) volume, particularly at low frequencies. It is almost certain that they will not 'see' the same external (acoustical) impedance. Further then, when connected in series, control over the pair becomes very different as these two different and varying impedances are now reflecting into each other - amp output impedance and cable resistance now being negligible. As you see, intuitively the series version might well be worse ... but it is better! The mentioned 'worseness' might well be countered by easier amp drive as said. That for now; I must go; other contributions are sure to come. Interesting problem ... [/QUOTE]
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Audio and Video Talk
General Discussion
Looking to expand my knowledge re. impedance and control
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