Sandy West

Suggest using "old concepts" 12 gauge stranded copper speaker wire.

Neither the 811 nor the 511 require a tweeter. Both are useful to 20,000 Hz and every crossover point degrades the sound, because you have two different drivers reproducing the same frequencies. Eliminating the midrange to tweeter crossover is one of the primary benefits of wide range horns.

As to comparing receivers and seperate pre-amps, the latter should be considerably better, as they are not sitting inside a metal box with tuner and power amplifier circuitry. Also, if you spend, say, $1000 for a receiver, that money must be divided between a pre-amp, AM tuner, FM tuner and power amp. Each part has received maybe 1/4 to 1/3rd of the design time and money. Spend $1000 for a pre-amp and it can be designed and built with much greater care. In this sense, less for a given amount of money really is more.

I have always thought that pre-amps make more difference in a stereo system than power amps, assuming that the latter are not driven into clipping. All amplifiers should be 100% accurate and thus identical, but the variations in design insure that this is not the case. Some are better (handle audio signals more accurately) than others and I have found that pre-amps are the most likely to vary. Perhaps this is because they are handling relatively low level signals, where a small change is more noticeable than it would be in a higher level signal.

Actually, that old saw about H-D vibration has not been true for many, many years. Ignorance keeps this kind of rumor alive.

Don't remind me. I just gave away (to a friend) my A7/500's and replaced them with RF-7 II's, having decided that Altec was never coming back. Now Klipsch . . .. Do you remember Sparkomatic?. They purchased pieces of Altec Lansing when it went under. Now everyone can afford an Altec system.

Your woofers should be a matched in stereo (two channel) loudspeakers. The best replacement, unless you intend to change the woofers in both speaker systems, is whatever the loudspeaker system originally used--a direct replacement rather than a substitution.

In my opinion bi-wiring is a waste of money, as you are putting the same full range signal from the same amplifier into both sets of speaker terminals, just as you are with one set of speaker wires and the (supplied) copper jumper strips in place. I have never heard any sonic improvement from bi-wiring. The drawbacks are increased complication, additional connections (never a good thing) and additional expense. I think bi-wiring was primarily devised to help retailers sell outrageously expensive speaker cables.

Chris, Sure, I'd agree with you if the qualifications you mention are in place. Someone with the education, experience and requisite test equipment is essentially a qualified engineer. These are not the people to whom I was referring when I wrote "basement inventors and shade tree mechanics" and I suspect that qenuinely qualified speaker modifiers are quite rare in the general population of Klipsch (or any other brand) loudspeaker owners.

I was bi-amping Altec Lansing (12" woofer w/3000 Hz horn), two-way monitor speaker systems with the crossovers between the stereo pre-amp and (2) stereo power amps. My crossover was custom built by an EE engineer friend of mine with a 12 db/octave slope and adjustable output to all four power amps. For several years I used a 40w stereo power amp on the woofers and a 10w power amp on the horns. (Both solid state.) It worked fine. Later I moved the 40w stero power amp to the horns and used a 75w stereo power amp for the woofers. This also worked fine. Later still I acquired Altec Lansing Voice of the Theater speaker systems (A7/500's) and drove them conventionally with a 125w/channel power amplifier (no bi-amping). This also worked fine and reduced the cable clutter. These pro Altecs are very easy to drive, with a 102-104 db SPL from 1 watt input at 4 feet! Two days ago I ordered a pair of Klipsch RF-7 II's and I will run them with the same Marantz 250M power amp, using the built-in passive cross-overs (no bi-amping). The A7/500's are off to a friend with a big house! These were and still are two channel, stereo music (only) systems. Hope that helps.

I owned a Sony deck--forgotten the model number. However, the best were generally considered to be: (1) Crown, (2) Revox, (3) Tandberg in stereo reel to reel tape decks.

According to Klipsch the RF-II's are improved, which makes sense, but I suggest you let your ears decide for you. Certainly the story about magnetic structures breaking is BS of the purest ray serene.

Twelve gauge stranded copper speaker wire should be more than sufficient for any home audio application. Exotic and expensive speaker wire is primarily a profit enhancer for the retailer with no measurable benefit to the consumer. Most exotic speaker cables don't hurt, but you'd get a lot more enjoyment by spending your money on CD's to listen to on your new speakers. Just my opinion, of course.

I think your basic question is a valid one. Any product can potentially be improved, but I wonder how many users have the technical expertise to change (in a positive way) a highly researched and developed product like modern Klipsch loudspeakers. My inclination is to trust the professional engineers more than the basement inventors or the shade tree mechanics.

Bi-wiring accompllishes practically nothing if you use good speaker wire in the first place (16 gauge or heavier for reasonably short runs, 12 gauge or heavier for longer runs). True (active) bi-amping with an external x-over between pre-amp and the power amps does, but you've got lots of power there and, if I were you, I'd use a single stereo power amp and conventional speaker wiring. The KISS principle applies.

The improvement in distortion is measurable. Intermodulation distortion is greatly reduced, almost to zero, as each amplifier is handling different parts of the frequency spectrum.

Trey, For years I bi-amplified a stereo pair of large, two-way, Altec-Lansing loudspeakers. However, I used a stereo pre-amp and external cross overs between the pre-amp and two stereo power amplifiers. I could trace the signal path and understand why this worked. I would love to read your description of why bi-wiring works (if it does). Let's use an RF-7 II loudspeaker as an example, since I'm purchasing a pair of them, driven by a typical stereo power amp (mine is a Marantz 250M). To my simple mind, running a two-conductor speaker wire carrying a full range signal from (for example) the right channel (plus and minus outputs) of the stereo power amp to the right RF-7 II's plus and minus cross-over input terminals (shorted with a jumper to a duplicate set of cross-over terminals) is electrically identical to routing the same full range signal from the amp's plus and minus outputs to both sets of the RF-7 II cross-over's duplicated plus and minus terminals using a "V" or "Y" speaker wire harness (without the jumper in place). Either way, it seems to me, the two "positive" input terminals on the cross-over see the same signal, as do the two "negative" input terminals. Where did I go wrong in this analysis? Thanks in advance for your thoughts!

Thank you! Excellent article on driver break-in. Confirmed my guesswork on the subject.

The A7/500's are spectacular, but I've already given them to a friend!

They more than hold their own. These sectorial horns were designed by James B. Lansing and are the best high fidelity horns ever designed. (Also the most expensive to produce!) Frequency response is 800-20,000 HZ in the case of the horns you need. You don't need the full range A7/800 system (800 hz horn plus 15" woofer) for your application, since you already have the 12" woofers, just the high frequency horn and its associated driver. I've had a pair of Altec A7/500 loudspeakers (500 Hz horn and 15" horn loaded woofer) in my Grade-A home stereo system for over 20 years. They bring out the best from my made in USA Marantz and McIntosh components and simply blow the socks off most high end home speakers. I am passing the Altecs along to a friend who can use them and downgrading to Klipsch RF-7 II's to free up a little space in my overcrowded living room, but I know that, as ultimate speakers, the Altecs are better. Closest to equivalent in the Klipsch line would be the La Scala theater speakers or the KHorns, which are also very fine full range systems.

If you want an 800 Hz crossover from 12" speakers, I'd suggest an Altec Lansing 800 Hz horn (#811B). Very efficient, extremely well made in the USA and used in many commercial theaters. The appropriate drivers are in the 800 or 900 series. You can buy one, or as many as you want on the used market. This is Altec Professional equipment, not the home entertainment line. Here is the online reference: http://www.altecpro.com/products/vintage/index.htm#horns

I'm pretty familiar with the PAT-4A, having used one for many years. I think that a C-12 and a PAT-4A would be fine together.

Complete words, what a concept! Gee, the content might even make sense . . ..

I read that Bestcovery selection in the course of researching RF-7 II's before I ordered them. I used Altec A7-500's in my 2-channel stereo system for the last 20 years, so the new RF-7 II's needed to be good to replace them. FYI, an audiophile friend of mine has a most unusual 7.1 system that uses Bose 901's as the side speakers. He uses Magnapans for the rear speakers, Snell floorstanders for the front right and left and an Altec A7-800 for the middle and subwoofer role. The 901's, which I don't like in 2-channel stereo mode, work well in his system.

Yes, they are good. I remember them as being the same power (60w RMS / channel) as the Dynaco Stereo 120, but probably better made. Definitely worth the price if working correctly.