Join Date: Jan 2005
Location: Irwin, Pa USA 15642 (near Pittsburgh)
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If nothing else there is a small home built kit, led watt meter, a "Velleman K4307: Audio Power Meter Kit." It has 10 led over the range and therefore can at least give you a feel of power sent to the speakers, not just they ae clipping now so muyst be full power just before clipping. It connects across the speaker terminals at the speaker or at the amp and is otherwise not powered. Parts express as well as Velleman sell them for about $33 to $44 each plus shipping costs to your location. I got two of them to try to see what my front and surround speakers were actually receiving at normal and high listening levels. There are marked overlays for high power applications of 4 and 8 ohm speakers. The scale for 4 and for 8 ohm are provided in two levels depending upon a single resistor value. The high power scale 8 ohm version has an led at 5, 10, 20, 30, 60, 100, 200, 350, 550, and 1000 watts. All leds are red. For a 4 ohm driver there is an overlay which shows double of each of these values i.e., 20 watts thru 2000 watts. .
A lower power version of the settings resistor which I built for 8 ohm goes from 0.15 to 200 watts. If for 4 ohm you use the overlay from 0.3 watts to 400 watts. The kit contains an overlay for 4 and 8 ohms in both low and high range setup.
It is a great little unit and takes about half hour to build. The only precaution is to only remove each part from the tape in sequence as it is called for . They are in a specific order in the tape strip but nothing tells you that. Just looking at the end part you can pretty mugh tell the direction you go. This is not needed for resistors if you have an ohm meter but for diodes and capacitors and transistors there are a couple of values and types and usually the average person does not have any meter to see what part you have in your hand. The markings on the faces of the transistors are tough to read so it is more important there to remove each transistor in order from the tape and install it in the next location. Circuit board and all parts (except a case if you want one) come in the kit. My subs have internal amps so it is useful for my bass and midrange speakers only. I found that my large front main speakers which are cut off at 60 cps by my AVR, a 25 watt peak was a real loud level. Efficiency is decent at 94 db/watt at one meter. I know this does not do exactly what you want but is a lot more detailed then any on amps which purely show clipping and maybe one or two levels below that. This 10 led scale is quite informative. At under $50 it is a nice toy.