Q&

Q&A - #3 - March 11, 1997
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Q Could you please tell me what the difference is between a TV monitor and a computer monitor?

A A TV has a tuner in it and only one scanning rate (60 Hz in North America, 50 Hz in Europe), and the scanning lines are interlaced. That is, first the odd numbered lines (1,3, 5, etc.) are put on the screen, then the even numbered lines (2,4,6, etc.). A computer monitor doesn't have a tuner, and it can scan at numerous scanning rates (depending on your video card), called the refresh rate, and, for the most part, is non-interlaced.

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Q Could someone please explain how to match speakers & amplifiers? Watts seem to be the main measure of power, but I have been told 100 Watts of 'Bad' power are not as good as 50 Watts of 'Good' Power. How do you tell the difference? Also, I am told you need more power to drive 4 ohm speakers yet I see amplifiers rated at 55 watts @ 8 ohms, 70 @ 6 ohms which seems to mean you get more power with lower ohm speakers. If I have speakers that are 75 watts per channel @ 4 ohms do I buy a receiver that puts out MORE OR LESS than 75 watts at 8 ohms? These might seem like supid questions, but I have never quite understood it.

A Not stupid questions at all. It can be very confusing. An amplifier delivers power to the speakers based on Ohm's law, which states that the Voltage (E), in Volts, is equal to the Current (I), in Amps, times the Resistance (R), in Ohms, or E=IR. Let's rearrange the equation a bit, so that I=E/R. Say that the amplifier is putting 16 Volts across the speaker terminals and the speakers are 8 Ohms. This equates to 2 Amps of current (2=16/8 in the equation). Now, say you change your speakers to 4 Ohms. At 16 Volts, the amplifier has to supply 4 Amps (4=16/4). To determine watts, the equation is P=EI, or Power, in watts is equal to the Voltage times the Current. So, for the 8 Ohm situation, the amplifier is delivering 32 watts, and at 4 Ohms, 64 watts. Herein lies the problem. Mass consumer electronics (amplifiers) are usually not constructed to deliver high current. It would raise the price too much. High-end amplifiers are usually rated easily into 4 Ohms (can deliver high current), and many are rated into 2 Ohms, and even 1 Ohm. So, if you have 4 Ohm speakers, you have to be very careful about the amplifier (receiver) you purchase. Get one that states an rms rating into 4 Ohms, 20 Hz - 20 kHz, not just at 1 kHz. Get as much power as you can afford. Consider a receiver that has pre-out jacks, so you can add high power, high current, outboard amplifiers later.

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Q What a great find you were today! Had several recommendations for Sunfire Cinima Grand 200W x5 and the Sunfire True Sub, wham, bam, Gooollleeyy Batman here it is! You guys have the reviews and The Man, Mr. Bob himself, ready to read and download! Man, even my DP-870 from Marantz was dissected in living color. No AV-600 preamp though, but hey I did punch in your numbers and not the psychic friends number! Anyway thanks already. I have a pr. of the big boys, Klipsch LaScala's and I love 'um. For H/T what do you rec. as good matches? They (Klipsch) do the KV-4 center but for surrounds? Heard their KLF 20's/30's, the best sonic match to the LS's but boy are they big boys for rear surrounds. Any suggestions? And some say yes add sub, some purests say no they will not match the speed of the LS's and don't worry about the lows you'll miss. Their tech. rep, Nancy, said the Heresey would be good, big too though. Also said maybe their soon to be released 2.1/3.1 line but didn't have much info on 'um. Because of their brightness and 104db sensitivity all other speaker manufacturer's cross their index fingers at me and say gotta stay with the K family. Anybody on your side of the Quantum Foam have any good old ADVICE? I would be mighty appreciative! Again I thank you already for the info I found and in advance for your time with my current quandry! P.S. You folks really have your act together!

A For home theater, and with Dolby Digital (AC-3, DD) or DTS, big rear surrounds are in order, because the rear will have full range sound. So, probably best to get more Klipsch. I would recommend adding a subwoofer. A big one, too. Velodyne F-1800 or M&K MX-5000THX would do it for you.