Does 4ohm Speaker Make My Amp More Powerful?
default -- Tue, 06/02/2009 - 12:38
I currently own the B&W 805 Signature speakers (8ohm/88dB). My integrated amplifier is the Mark Levinson 383 w/ 100w at 8ohm and 200w at 4ohm. If I changed my speakers to Dynaudio Confidence C1 (4ohm/86dB) will my amp, in real world terms, sound more powerful?
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The above post is mine.
In a word, no. The new 4 ohm/86db speakers you seek are less sensitive than the 8 ohm/88db speakers you already own, thereby requiring your amp to work much more harder. The amp will run hotter with the lower db sensitive speakers than it do with the higher db sensitive speakers. If you want your amp to sound more powerful, buy an even higher sensitive speaker at around 93db up. Good Luck.
I'm looking for a two way that will work in a smallish room, but one with good bass extension. I can't think of a speaker that meets that criteria, offers performance beyond my current B&W 805 Signatures, AND has >90db sens.
A more basic question: how do I know if my system would benefit from more power or, alternatively, more sensitive speakers?
Have you considered adding one of the b&w 800 series subwoofers to your system? It would allow the 805's to play slightly louder and faster while adding the bass you want. It should be a very good match in both appearance and sound quality. Adding the subwoofer would also ease the power output burden of your amp making it sound more powerful. This could become a two for one deal for your system. This way is a more sure thing than trading out your speakers for another small two way and maybe not gain much of anything. Remember, there are no absolutes to this hobby. Just the love of music.
I haven't considered this much, but.....
Hello,
As you literally phrased your question "Does 4ohm Speaker Make My Amp More Powerful?" ... No. Here is why. Your amplifier was designed to be able to continuously output a certain amount of RMS Watts per channel at a given (and nominal) impedance value of either eight or four Ohms (regardless of and completely indepent of the speaker's voltage sensitivity or efficiency value). The only way that the amplifier could become more powerful (as you phrased your question) is if it were modified or redesigned by the manufacturer or a competent technician to be more powerful. Sometimes that can be done by adjusting the bias on the output tubes or transistors, adding more output tubes or transistors and all the other circuitry that it would require, changing resistor values as needed, upgrading the power supply with a larger transformer, increasing the high voltage supply rail voltages for the tubes or for transistors, higher values of storage capacitors, etc. A nominal imedance rated four Ohm speaker (versus and eight Ohm one) will (for solid state only) typically double the output power of the amplifier due to halving the nominal impedance which in turn doubles the current flowing through the output devices and through the speaker. In a tubed amplifier, that having of the speaker's nominal impedance halves the damping factor (the ratio of the amplifier's output impedance to that of the speaker) and there is a resultant halving of power transfer that way. The reverse is true for doubling the nominal impedance of a speaker for a tube amp (i.e. going from a four Ohm speaker to an eight Ohm or an eight Ohm to a 16 Ohm one, etc.) I hope this helps.
Tom