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<blockquote data-quote="John Roberts" data-source="post: 145747" data-attributes="member: 126">Re: Damping Factor - Actual listening tests?Not to quibble but if you look at that article&#039;s electrical model the voice coil resistance and inductance is in series, so the ability of amplifier output impedance to damp that motor mass could indeed make a difference between high output impedance tube amps, but low Z&nbsp; solid state amps will all be similar and dominated by voice coil impedance. Of course if you use 4-8 ohms worth of wire resistance it should matter. Peavey (Sondermeyer) got a patent for an amp that used a feedback trick to deliver silly high damping factor. In fact we could actually deliver a negative output impedance, which could compensate for wiring losses outside the amp too. I didn&#039;t even try to market this (I was power amp PM at the time) since I feared Peavey customer&#039;s heads would explode. I am not smart enough to do this myself but think there might be some tricks possible inside a powered speaker to drive individual drivers from a negative source impedance, but that was even further from Peavey&#039;s sweet spot in the marketPeavey (Sondermeyer/Brown) also patented amps with variable damping factor for use inside guitar amps to help solid state guitar amps mimic tube amp&#039;s interaction with driver/cabinet resonances. IIRC the peavey guitar amp feature had separate HF damping and LF damping adjustments (while they didn&#039;t call it DF). So if you want to hear really low DF maybe check out one of those Peavey guitar amps. <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f642.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":-)" title="Smile&nbsp; &nbsp; :-)"&nbsp; data-smilie="1"data-shortname=":-)" /> (Audibly these circuits would enhance speaker voicing resonances, a part of guitar amp design, but now with a &quot;more&quot; knob.) I didn&#039;t read that paper word for word, but since it comes from a power amp company I suspect they are promoting their amps as somehow better in this regard. Crown was notorious for hyping DF well beyond useful amounts.With the exception of Tom Danley&#039;s old servo woofers loudspeaker driver position is not strictly controlled, just accelerated in one direction or the other. Remarkable they work as well as they do.&nbsp;&nbsp; JR</blockquote>

[QUOTE="John Roberts, post: 145747, member: 126"] Re: Damping Factor - Actual listening tests? Not to quibble but if you look at that article's electrical model the voice coil resistance and inductance is in series, so the ability of amplifier output impedance to damp that motor mass could indeed make a difference between high output impedance tube amps, but low Z solid state amps will all be similar and dominated by voice coil impedance. Of course if you use 4-8 ohms worth of wire resistance it should matter. Peavey (Sondermeyer) got a patent for an amp that used a feedback trick to deliver silly high damping factor. In fact we could actually deliver a negative output impedance, which could compensate for wiring losses outside the amp too. I didn't even try to market this (I was power amp PM at the time) since I feared Peavey customer's heads would explode. I am not smart enough to do this myself but think there might be some tricks possible inside a powered speaker to drive individual drivers from a negative source impedance, but that was even further from Peavey's sweet spot in the market Peavey (Sondermeyer/Brown) also patented amps with variable damping factor for use inside guitar amps to help solid state guitar amps mimic tube amp's interaction with driver/cabinet resonances. IIRC the peavey guitar amp feature had separate HF damping and LF damping adjustments (while they didn't call it DF). So if you want to hear really low DF maybe check out one of those Peavey guitar amps. :-) (Audibly these circuits would enhance speaker voicing resonances, a part of guitar amp design, but now with a "more" knob.) I didn't read that paper word for word, but since it comes from a power amp company I suspect they are promoting their amps as somehow better in this regard. Crown was notorious for hyping DF well beyond useful amounts. With the exception of Tom Danley's old servo woofers loudspeaker driver position is not strictly controlled, just accelerated in one direction or the other. Remarkable they work as well as they do. JR [/QUOTE]

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