Half scale La Scala built and tested

[Neandertal]

Hello,

I have finished my small fit of madness and have completed a one-half scale (give or take) La Scala. This was the result of having all the odds and ends left over from my custom center speaker project, plywood in hand, and a real desire to play with a "folded horn" The attached picture compares the results with one of my Heresy IIs.

I had the following orphaned parts looking for a home:

Woofer: Klipsch K-1008-KV (from KG2.2V) 6.5" cone at an estimated 88 to 90db/meter, 50hz to 2200hz

Mid: Electro Voice MR-10 4"x10" metal horn at a 101db/meter, 1000hz to 3500hz (best range per EV)

Tweeter: Radio Shack 2"x6" "Tweeter" at 92db/meter, 1,800hz to 30,000hz (pretty cheap but useable)

L-Pad from EV 12TBRX for reducing the mid horn output

3-way crossover: Radio Shack "Universal" with modifications for 750hz and 4500hz points

Several sheets of 3/8" plywood (hey!...half scale to 3/4" plywood...go figure!)

I used the La Scala dimensions and I scaled them down 50% for all the base bin construction. All measurements were within 1/16" of the half scale numbers for the base bin. The upper section had to be taller than half scale to fit in the two horn components. The final speaker is 20" tall, 12" wide, and 12" deep.

I have been listening to it all day and can comment.....intersting. It has a definate different sound than the Heresys but not too bad. My first surprise was that it had a strong output. I do not have any technical equipment to make measurements, but it sounds volume output to be the equal of the Heresy II at the same amp input. The base was loud! Considering the driver is 6.5" in size, I had hoped the folded horn design would up the output and was very impressed that it matches the volume output of say 94 to 96db/meter?

Now the draw back....it fails at 80hz. I input test tones and spot the roll-off at about 75 to 80 hertz. Output is real weak at the 50 to 60 hertz range. The small mouth size of the half-size base horn would and should have an output low limit of about 80hz, so no big surprise. I have tested it with a full range of input values and DO NOT find any output "holes" in the upper base. No serious drop in the 400hz to 750hz range. (Remember I am testing by "ear") Base output sounded like it had a minor peaked at about 250hz with maybe another one at 500hz. From 80hz to up to the mid horn....no noticable dips.

The mids are very sweet. The EV MR-10 has the same basic horn proportions as the K700 and sounded very matched to a Klipsch K-53. The tweeter held it's own as supporting the overall combo but fell on it's face at 12,000hz (or at least my ears do!).

To describe the sound....airy...sweet in the mids but lacking strong definition at the lower range. When listened with my sub set at 80hz to support the low end...it sounded OK but not a real equal to the Heresy. The Heresy is strong and "velvety" and rich (I like Heresys) and my creation is airy, "lite", less defined. I will say it sounded very good with female voices and strings, but was lacking on good old rock-n-roll. It is a good match for "mystical" type sounds and real good with the "blues". I do speculate that some of the lack of definition in the lower tones may be coming from the thin plywood walls of the base bin "flexing" and thus smudging the base a bit. Does sound good with the "dirty blues". Examples:

Good: Judy Collins "Send in the Clowns", Moody Blues "Nights in White Satin", real good with B.B. King "The Thrill Is Gone", and Led Zeppelin "Stairway to Heaven"

Bland: Santana "Black Magic Women", Elton John "Levon", and David Essex "Rock On"

Poor: Iron Butterfly "In A Godda Da Vida"

Overall...anyone who wants good, "small" speakers should stick with Heresys and a small sub. The end result is that this experiment will work well in my garage. A lot of work with interesting results but no great break-throughs. Maybe this example will keep others from trying what I am sure Paul Klipsch probably tried and discarded 50 years ago.

I will also be posting a few construction pictures for your review.

Bert

[Neandertal]

Woofer being sized in the "dog house" of the construction.

[Neandertal]

Back of the flare to be hidden with the outer shell of the base bin.

[Neandertal]

Individual upper components before installation.

[Neandertal]

View of the crossover with the recycled L-pad for mid tone control.

[Neandertal]

A better view showing the relative size of the mini-scala with a Heresy II.

[Neandertal]

A back view of the two spaekers.

[mobile homeless]

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[maxg]

Looks like a very interesting experiment. The 80 Hz lower limit is a bit high and unfortunate - seems that PK was right after all in his heresy of using a woofer rather than a folded horn in the smaller box.

Of course taking into account the sealed box of the Heresy we still have the limited bass problem (around 50Hz) but it is not as limited as your creation in that department.

When I set about building my own speakers it was also with the Heresy in mind. I worked on the theory that using a smaller woofer in a larger box would allow more "room to breath" and therefore a more extended bass. To an extent this has certainly worked although I am getting rather more variation in output levels than I had hoped. For some reason I am yet to fathom 40Hz is something of a black hole playing 5 dB lower than 35Hz and 8 less than 45.

Other than that there are various troughs and peaks up to 1000Hz - although non as heavy as the one mentioned.

I guess there is more to this building speakers lark than meets the eye.

Still the use of real wood, as opposed to MDF / plywood etc has given a fabulously warm flavour to the sound that makes the Heresy sound seem thin and light by comparison. I now use these as my main speakers with the Heresy's being piled in the corner.

One day I will have another go at persuading myself to sell them, along with the REL Strata 3 sub which is no longer used.

[maxg]

Thought I would include a pic that I posted some time ago. If this works the speaker should appear below: