Klipsch's best midrange sound quality

[Marvel]

You can read this explanation of autoformers from the Community Light and Sound document. Basically, it's a single coil with multiple taps.

On Klipsch crossovers, the autoformer is used to change the levels on the midrange driver (ofter alled the squawker in Klipsch terminology).

http://www.communitypro.com/files/literature/tech%20notes/AUTOFORMER_TECH.pdf

Bruce

[SebastienL]

Hi Bruce,

The text you provided is concise and clear. From it, I retain this: "...Autoformers have performance advantages, too. They have increased power handling capability, flatter frequency response, lower insertion loss and lower distortion than conventional transformers of similar size and cost..." It's easier to understand such use in a speaker.

Sébastien

[erik2A3]

I also have my crossovers outside the la scalas, which are positioned next to our klipschorns. As you have read, the autoformer is just a way of balancing the output of the squawker relative to that of the woofer and tweeter. As mentioned above, it is essentially a multi-tapped choke, since it does not have a true primary and secondary winding. Most loudspeaker systems do NOT use autoformers, but rather single series resistors or a so-called L-pad, one in series and the other in parallel with the voice coil of the driver. More recent Klipsch speakers do not, to the best of my knowledge, still use the autoformer - some have indicated it was a choice based on higher cost of the autoformer.....an assumption with which I do not necessarily agree.

There are often debates over whether resistor based L-pads or autoformers are better, though it's my opinion, based on extensive listening to identical networks -- where one provided midrange attenuation with an autoformer and the other using non-inductive resistor based L-pads -- that the autoformer seemed somewhat opaque or veiled compared to the network using resistors. ALL of our listening impressions are entirely subjective, however, and I can only speak for myself. Some systems use variable L-pad controls, which function by maintaining a constant impedance load for the amplifier, but make it very easy to turn the squawker up amd down just like a volume control.

It needs to be said again that changing positions for the squawker output from the autoformer causes a change in impedance. Since crossover frequencies and subsequent values of capacitance are based on the impedance of the drivers in question, one ideally should not simply change taps on the autoformer without also altering the value of capacitance appropriate for the resulting change in impedance, such as would be found if changing from tap 4 to tap 3 on a type A network.

We have Klipschorns in corners about 22 feet apart, with La Scalas to the insides, about 18 feet apart from one another. As others have indicated, I also agree that the K-horns offer a more comprehensive snd balanced frequency response, but I prefer the La Scalas on some genres of music, such as classical guitar and Baroque, jazz trios, and so forth. For me, the most transparent of the Klipsch crossover networks for the Klipschorn and La Scala has consistently been the type A. Doing some experimenting with much more power than I normally ever use, I found the type AL extremely satisfactory, yet very dull and lifeless when the same network was used with our usual diet of sub 5 watt single ended triode or OTL amplification.

Have fun on this journey! Erik

[erik2A3]

I would like to,also mention that, using the same Crites tweeter often mentioned here, I have experimented not only with the 4,500 cycle crossover point, but also wound my own, precisely measured inductors, for crossover points of 2,500 and 3,500 Hz. I used third order networks in these lower ranges to provide a sharper cutoff and protection for the tweeter, but maintained a simple bandpass and variable or fixed L-pad for the squawker.

There are a number of ways of mildly altering the overall tone of these speakers, such as methods of making them sound less bright . I have done some of the published changes that have been posted over the years, And agree that some of the brightness was reduced, but unfortunately so was much of the character that first captivated me when I heard a pair of Heresies in college but couldn't afford at the time. What sounds good to one person, whether a brand of capacitor, a crossover design, or anything else -- might be a completely different story for someone else. Erik

[SebastienL]

Hi Erik,

Could you tell me some precisions on the "type A" network (particularities, years in use, etc.)?

Thanks,

Sébastien

[erik2A3]

Good morning, Sebastien

There is extensive information here regarding the type A network, which I believe was in use from the early 1960s to early 1970s. That is a rough estimate. It is among the most simple Klipsch Heritage designs, and seems to be favored by many who have low powered amplifiers -- as in the 1 to 10 watt range. It uses the least number of parts, with just a couple of capacitors in the Mid / HF branch of the network, for a crossover point around 6 kHz, and a single series inductor for the low-pass section. Because of the low order slope, there is greater overlap between the drivers, however there is also less insertion loss, which is a benefit if one does not have too many watts to begin with. I have also had excellent results with this network sans inductor on the woofer, for an even simpler design.

Because of its simplicity, it is also an extremely easy network to use as a basis for experimentation. Many enjoy modifying the original design with like-value modern capacitors of various brands and construction. One can season to one's taste as far as that goes.....the "which-capacitor-is-best" battles of past forum history are rather silly (including my own contributions) though entertaining.

The type AA is slightly more complex, but also very much liked by some owners. If you do any DIYing, these crossovers make very good first build projects; they involve only a small handful of connections. They are also available new and well-priced on ebay from a very capable gentleman. You can also find used ones that are not too expensive. Apologies for the lack of paragraph breaks in my text. By the way, the lower crossover points mentioned above are NOT suitable to the stock K77 tweeter. They are used with the tweeter sold as a drop in replacement.

[Chris A]

KPT-402-MF, driver of your choice, various Klipsch EV or TAD, I'll let others with a little more experience with the 402 chime in with the specifics on that.

If Kudret still owned his Jubs, that would have provided a set of K-402s w/TADs to hear in eastern Canada.

Chris

[psg]

KPT-402-MF, driver of your choice, various Klipsch EV or TAD, I'll let others with a little more experience with the 402 chime in with the specifics on that.

If Kudret still owned his Jubs, that would have provided a set of K-402s w/TADs to hear in eastern Canada.

Chris

Amazed that he sold them... And amazed I didn't buy them... The timing wasn't right for me.

I pointed the OP to Formica; let's hope he's around and willing.

[SebastienL]

Hi Erik,

Thanks for your detail on the type A network. I better understand why some people may prefer the older version of Klipsch.

Sébastien

[ClaudeJ1]

Sébastien,

Welcome to the Klipsch forums! Since the LaScalas and Khorns share the same mid and tweeter, they can both sound delightful. With the LaScalas, the mids and tweeters are often attenuated a little by adjusting the crossovers. On the LS, this makes the mids not seem as harsh/forward, and makes the bass seem a little more 'there'. In other words, the balance on the LS can be made smoother by pulling down the mids a little.

The autoformer on the crossovers allow for this adjustment to be made.

Bruce

I have owned 2 pairs of Khorns 5 pairs of LaScalas, Cornwalls, MWMs with various horns, including upside down LaScalas (what you are about to hear about) about 8 pairs of Heresy I i.5, II's etc. KG2's, 2.5, KG4's (in house and CAR), on and one

The BEST sound for midrange (assuming you stick to ALL Klipsch components) is the LaScala with a K-43 woofer (not the K33 that comes with it).

[ClaudeJ1]

Regardez ma recommande s'il vous plais! Je suis nee a Montreal.....demenage a Detroit dans l"anne 1964. Klipsch depuis 1977.