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tubesandhorns

LaScala port- rear or front?

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I have been toying with making what I call SuperScalas- ported La Scala bottoms, CP25 tweeter, and a BMS4592 coupled to probably either a Volti FC260, a Eliptrac, or a Stereo-Lab CF250... as illustrated. If I seal off the top and port that, I can put the tweeter on that section and put the mid horn on top. This looks pretty much perfect to me. Only remaining question (yeah, right) is to port out the front or port out the back. Dave touched on that briefly a couple of years ago, but I was wondering if any of you have any experience with playing with that variable.
Any thoughts out there?
Also, if I have drastically missed something, when you get up off the floor from laughing I would love to hear what that is.

post-50085-13819830457844_thumb.jpg

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Welcome to the forum. If you have been here for a while but not a memeber for long then you already know what a great place this is. As to your vent question you have a lot of options available. Consider the frequency of those vents and the wavelengtn and you can see that from a loading point of view thatthey canbeplaces anywhere and work just fine. You need to consider where and how the speakers are to be installed as that may impact your choice of port location. Of course there are the standard physical considerations of cabinet dimensions and your vent dimensions that you will have to consider. Remember that a clear unobstructed distance of at least the vent length should be provides on either side of the vent (that's inside and out).

I am curious why you have not considered turning your LaScala into two way rather than three ways? Given the bulk of the LaScala which can be imposing in many domestic situations it seems to me a good choice to ensure sonic intigration of the mid/hi horn and woofer horn over the shortest possible distance (to the listening position). There are lots of members who have hands on experience and I hope that you getall of your questions answered. Best regards Moray James.

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I have seen where some here have ported out the bottom by adding a box to bottom. Makes it easier to return to original seems to me this is the way to go. Just my thought...Rick

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I asked the same question before I vented out the backs of the tops. The short answer seems to be that it makes no difference sonically. At least any sonic differences are way less significant as compared to issues of appearance, ease of mod, ease of reversal, etc.

Forum member djk, who first proposed the most often copied mod, seems to believe it makes no difference. Forum member Dr. Who applied his academic credentials in agreement. At least that is how I interpreted their comments.

There are many threads regarding the La Scala bass bin mod. In some I started there are links to others. Search this forum and Google for "djk bass mod" and you'll get more results than you're likely to absorb.

IMO, if La Scalas alone don't satisfy your need for bass, try the bass reflex mod or add a sub, preferably not a direct radiator.

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If the area where the mid horn is normally installed will only contain the tweeter and ports, you may be able to make the height a little smaller, as the K400 horn would not be taking up space. The ports could also be a single slot, but the dimensions work out a little differently.

Bruce

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I have been toying with making what I call SuperScalas- ported La Scala bottoms, CP25 tweeter, and a BMS4592 coupled to probably either a Volti FC260, a Eliptrac, or a Stereo-Lab CF250... as illustrated. If I seal off the top and port that, I can put the tweeter on that section and put the mid horn on top. This looks pretty much perfect to me. Only remaining question (yeah, right) is to port out the front or port out the back. Dave touched on that briefly a couple of years ago, but I was wondering if any of you have any experience with playing with that variable.

Any thoughts out there?

Also, if I have drastically missed something, when you get up off the floor from laughing I would love to hear what that is.

Front vs. Rear Port:

The other guys have more experiance with speakers and are probably right. From a Mechanical Enginnering standpoint they are correct. There would be verry little, read no difference, in total output/damping factor front versus back - Not enough tight bends to change damping if port area is the same.

The only variable would be if ported out the back, distance to rear the wall could be an issue, if too close the flow of air could be slowed enough to affect the sound.

Mids on Top:

Sounds like you have seen posts from indyfan and checking out what Volti audio is doing.

One of best mods for La Scalas. For two channel it puts the vocals etc. at the correct height. For movies on my system the sound is more realistic - comes out the screen instead of below the screen.

Also allows bass bins to point along the wall and mids to be toed in towards main listening position. Speaker placement and getting lucky with room geomerty has almost eliminated my need for porting, but I do have a sub. Sub is mainly for movies but does help on some music.

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I have been toying with making what I call SuperScalas- ported La Scala bottoms, CP25 tweeter, and a BMS4592 coupled to probably either a Volti FC260, a Eliptrac, or a Stereo-Lab CF250... as illustrated. If I seal off the top and port that, I can put the tweeter on that section and put the mid horn on top. This looks pretty much perfect to me. Only remaining question (yeah, right) is to port out the front or port out the back. Dave touched on that briefly a couple of years ago, but I was wondering if any of you have any experience with playing with that variable.

Any thoughts out there?

Also, if I have drastically missed something, when you get up off the floor from laughing I would love to hear what that is.

Interesting.

Trying to think this through. What would be the design goal?

A port is

typically used to extend bass response. I got that. But compared to a seal box

the woofer output is substantially reduced at a given resonance and replaced by

the vent output. In this case though the woofer is horn loaded. Would the vent

also be horn loaded to maintain overall sensitivity from both outputs?

In

other words, aren’t you going to lose some already-limited horn bass response and

replace it with the vent response at a substantially lower output level?

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No. At its low frequency limits, La Scala is already functioning as a sealed box. Adding a tuned port enhances the low frequency output, while still functioning as a horn from ~50hz to 400hz. The tradeoff is slightly reduced efficiency. To my ears, the bass is still "La Scala" fast and tight.

Altec's VOT, and others, have utilized horn/reflex hybrid bass for years.

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the lascala design is OK the way it was designed - you forget the experience that Klipsch had undertaken while designing the lascala speaker -and even more considering the industrial lascala setup -

-the factory had divised a setup where one could add a second lower bass bin - or even a second tweeter mid section on top - you could go as high as you wanted as long as the bass bins were at the bottom stacked and the same for the mid-tweeter sections -

-the separate crossover section for the LF and HF used in the lascala II - is the other improvement ala KHORN -

-the first error of your design is to mess with the tweeter position - as the sound dispersion will be off - you will be searching for the sound caracteristics like a mad man -

-the new lascala II have a seperate components bass bin and mid-tweeter section design - even Volti designs had a lascala section reversed ala Khorn which according to the creater was very good sounding -

- you design is very interesting in the choice of higher quality components - but in order to properly create a superior sounding speaker versus the original Paul Klipsch Lascala design - you would need an anechoic chamber to measure what you are really achieving as an improvement if any -

-purchasing the newer klipsch made components - crossovers -midrange-tweeter is a sure way to realise your goals - These alone will make you not want to modify the current lascala setup for years to come - and the whole improvements were tested in an anachoic chamber - this factor alone is how sound engineers work today - you can spend a lot of money and be back at square 1 - we have all tried but only a few have succeeded in creating a better lascala speaker since investing in an anachoic chamber is prohibitive- microphones alone can cost 50k -

good luck with your project -please send us pics of your creations - as we are all drooling to see more - take care

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"purchasing the newer klipsch made components - crossovers
-midrange-tweeter titanium upgrades is a sure way to realise your goals
- These alone will make you not want to modify the current lascala
setup for years to come -"

No titanium here:

La Scala II Floorstanding Speaker


  • BUILT FROM:
    2006

  • CROSSOVER FREQUENCY:
    HF: 4500Hz
    MF: 400Hz

  • DIMENSIONS:
    38.5" H (97.79 cm) x 24.25" W (61.60
    cm) x 25.25" D (64.14 cm)

  • ENCLOSURE MATERIAL:
    Birch Plywood and MDF

  • ENCLOSURE TYPE:
    Fully horn-loaded

  • FINISHES:
    Walnut Lacquer, Cherry Lacquer, Black Lacquer

  • FREQUENCY RESPONSE:
    51Hz-17kHz +/- 4dB

  • MAXIMUM ACOUSTIC OUTPUT:
    121dB SPL

  • MID FREQUENCY HORN:
    Exponential Horn

  • MIDRANGE:
    K-55-X 2" (5.08cm) Phenolic diaphragm compression driver

  • NOMINAL IMPEDANCE:
    8 ohms

  • POWER HANDLING:
    100 w max continuous (400 w peak)

  • SENSITIVITY:
    105dB @ 1watt/1meter

  • TWEETER:
    K-77-F 1" (2.54cm) Phenolic diaphragm compression driver

  • WEIGHT:
    175.5 lbs unboxed

  • WOOFER:
    K-33-E 15" (38.1cm) Fiber-composite
    cone / folded horn-loaded

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- indeed the Atlas sound PD-5VH Klipsch outsourced midrange driver - and the Phillipines made K77 F tweeter for the Lascala II - both diaphragms are constructed of cloth-based phenolic - my error - my mind was wondering at the same time with a cornwall III upgrade that I was doing -

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