DIY Academy from KG4 components?

[jtnfoley]

Any thoughts on making an Academy-equivilent from KG4 components? I've got some KG4s (and 2s, FWIW) that are definate donor candidates: All the usual abuse... water stains, scratches, cigarette burns...

The specs pages list different years of manufacture, different drivers (but close efficiency) but fail to list an HF crossover poing on the KG4 (or 2.)

[theplummer]

I think your on to something. I've often wanted to experiment creating a Chorus Center, It's tough to do though.

A KG4 might be perfect for that. What if you used the existing cabinet, but cut the motor board out, leaving about 1/2 to 1" of motorboard intact, then made a new one and split the woofers apart and place the horn betweeen them, rotating it 90 degrees. Screw some narrow strips of plywood on the inside of the motor board you just cut out, leaving half of the strip visible from he outside, then screw the new motorboard to the strips, fill with wood putty and paint.

Take the riser off the bottom, paint it black and set your television on top of it, Voila, Academy on Steroids.

[dougdrake]

Guess I'm wondering how it would be an Academy-equivalent with different drivers, specs, etc....?

[theplummer]

Guess I'm wondering how it would be an Academy-equivalent with different drivers, specs, etc....?

Huh???

[dougdrake]

Guess I'm wondering how it would be an Academy-equivalent with different drivers, specs, etc....?

Huh???

The OP said he was considering making an Academy-equivalent, but using KG4 parts, so I'm wondering how it would be equivalent to an Academy if it were made with parts from a KG4, which are different than the parts in an Academy.

[theplummer]

My best limited educated guess would be to say, If a cabinet built to the exact diminsions of the Academy were built and KG4 components were installed, then No it would not compare to an Academy. The values of the woofers are different and require a volume of air inside the cabinet that has already been engineered by Klipsch.

That's why my first post was to just cut the existing motor board and Re-orient the woofers and rotate the horn, in just as an Academy is configured. This also retains necessary cabinet volume and also allows the passive radaitor to continue to be used, an Academy size cabinet won't allow for a 12" Passive Radiator to be used.

[DrWho]

What is the goal here? A center channel between some KG-4's or between some other mains?

[dougdrake]

What is the goal here? A center channel between some KG-4's or between some other mains?

Sorry, that's far too logical a question to pose and we will have to ignore it. [*-)]

[jtnfoley]

I'd like to get as close as is reasonably possible to the performance of an Academy for something like a reasonable price...

One just went on eBay for nearly the cost of my mains, which are designer La Scalas in laquered birch.

I have two KG4s in poor physical condition (poor enough that I would probably not be inclined to keep the carcases and replace the mortorboard.) Seing the responses so far, I guess I can phrase the specific question: What kind of performance should I expect from a KG4 crossover, woofers, and horn, in a sealed enclosure of arbitrary size made for the purpose? (And, what size enclosure?)

I'm more than handy enough to make a nice, stiff speaker box in birch ply and match the finish on the La Scalas (I'll even try to match the 1983 original mint-condition cane grills )

I had, of course, planned to turn the horn 90 degrees to orient its' output correctly, but running the KG4 woofers (normally backed by the 12" passive) in a sealed enclosure is the question.

[DrWho]

One quick comment: the horizontal configuration for a speaker (as if often seen for center channels) is a compromise. The ideal driver configuration (especially for a center) would be to have a vertical array of speakers (aka, the stock KG-4). This has to do with the fact that a horizontal speaker has narrower horizontal polars (think focusing of a spot light).

That said, no matter what you do with your KG-4, it's going to sound like a KG-4 (or worse if you screw something up). Since you already own a pair, have you ever just tried one of them as your center channel to see how it sounds between your lascalas? If you like the sound, then all you need to do is build an enclosure with the exact same internal volume. You can even reuse the passive radiator if you have enough room behind your speaker (or if you want a smaller port, you're already aware of that other thread). For what it's worth, the passive radiator is gonna perform better than a port...

[jtnfoley]

A KG4 (even horizontally arranged) is too tall. It'll be sitting on top of a large subwoofer between the La Scalas, directly beneath my front projection screen.

I've tried the KG2, and am currently using a 2.2 (which will become my rear surrounds if i ever get around to fabricating brackets.) I'll have to try an unmodified 4 for a while to see how I like it, video obstruction notwithstanding.

I looked into DIY speaker construction before finding my current sub, and am familiar with the benefits of PR versus ported. I wonder whether reaching that low on a center channel is even needed (i.e. the poor bass response of sealed might not be a factor for the mostly voice content of movies.)

Your comment about a KG4 clone with the same volume has me thinking... I wonder whether a smaller visual cross-section can be achieved by making a box on feet with the PR downward-firing. This would allow me to use the depth of the box to accomodate the 12" diameter of the PR and then limit the height to the 8" woofers + material thickness and trim.

Of course, IIRC a portion of the effectiveness of a PR is the fact that it is out of phase with the woofs... or am I overthinking this? (A very distinct possibility... very low freqs don't tend to be directional...)

[DrWho]

Yea, I doubt reaching that low is really required either. I wouldn't mount the PR to be down-firing though because it's gonna cause it to sag a bit and introduce non-linear movement. Down-firing will require space too and make the cabinet taller.

Since you've got a height restriction, I would probably go with sealed or vented.

[Releaf1]

I appreciate DrWho's response and direction to my thread on this subject from the other day, but I was left with similar questions. I understand that the bass will suffer by going from the rear PR to port(s), but am not as concerned on a center as I would be with the mains. I'll live with that trade-off to be able to build into the wall. So if I'm not concerend with the bass, why not just seal it? What can of worms does that open? And I've read threads indicating that on a horizontal center, the woofers should be mounted on each side of the horn and other threads stating that they should be mounted next to each other and not seperated. And that the wall of the cabinet can be a wall of the slotted port and others that say the slotted port should be at least 2" from the cabinet wall. Does it matter? And how would a modified kg4 perform with the PR mounted in front? It would obviously be a taller and therefore need to be thinner to keep the internal cabinet volume constant. But then the mains could also be mounted into the wall.

Certainly appreciate the advise/direction here, just seem to have more questions the deeper I get.

[DrWho]

This is one of the reasons being able to measure DIY projects is so convenient. You'd be able to tell if the sealed enclosure was affecting the performance above 80Hz.

I suppose you could just give sealed a try and if male vocals (particularly the deep voiced announcer types) sound a bit thin, you could just add the port.

[theplummer]

I'd like to get as close as is reasonably possible to the performance of an Academy for something like a reasonable price...

One just went on eBay for nearly the cost of my mains, which are designer La Scalas in laquered birch.

I have two KG4s in poor physical condition (poor enough that I would probably not be inclined to keep the carcases and replace the mortorboard.) Seing the responses so far, I guess I can phrase the specific question: What kind of performance should I expect from a KG4 crossover, woofers, and horn, in a sealed enclosure of arbitrary size made for the purpose? (And, what size enclosure?)

I'm more than handy enough to make a nice, stiff speaker box in birch ply and match the finish on the La Scalas (I'll even try to match the 1983 original mint-condition cane grills )

I had, of course, planned to turn the horn 90 degrees to orient its' output correctly, but running the KG4 woofers (normally backed by the 12" passive) in a sealed enclosure is the question.

Ok, Now we have a little more info.

First let me qualify that I respect and trust Dr Who's opinion without question. He has great theoretical knowledge about which he speaks, but, I think sometimes he (we) get wrapped up in the proposed issue, without first knowing the ultimate goal the question is ultimately trying to achieve.

I see in this post you finally identify what your mains are (Lascalla's), and that you want to use a sub between them, and height is an issue as you want to set your new center on top of the sub.

Now that I know what you want to do, I believe you want an Academy equivelent at a lesser price. Let me say without a doubt, you DO NOT want an Academy (or anything like it) to be a center for Lascalla's. This speaker is not a good match for Lascalla's Niether is any of the KG series.

Khorn, Lascalla, Belle, Chorus I & II, and Heresy I & II are the only speaker in the heritage speakers that actually match each other with any degree of "family" sound. I believe the Academy fairs better with Forte I & II, Quartet, Kg's, and KLF's. If you temporarily install one of your Kg's in the center, then do a surround test from any DVD that contains the test generator from Lucas film THX optimizer, I think you'll agree that the Kg is not a good match for the Lascalla's. And in the words of IndyKlipschFan, "Timbre does matter".

Your best bet would be to find a split Lascalla and place the bass bin on the floor next to your sub, and mount the upper section above your screen, pointing at the "money seat". That's the best scenario that I can see. Your next bet would be to find a new spot for your sub and install a Heresy I or II with a slant back riser, directly on the floor in the center of your screen. Or, If you just gotta fiddle with something, sell your Kg's and try to find a Chorus II, create a new motor board for that speaker, lay it on its side and build a similar slant back riser for it and place it in the center of your screen.

The spl's of the speakers I've suggested will more closely match what you already have, and I believe the options I've given will be more economical than that elusive Academy that everyone thinks that they have to have.

I think Doc will agree about what I've said here due to the fact that he has personally heard my Chorus/Academy/Chorus soundstage and he realizes that the timbre match is not good.

[DrWho]

I think sometimes he (we) get wrapped up in the proposed issue, without first knowing the ultimate goal the question is ultimately trying to achieve.

lol, that's why I asked him to put the KG-4 up as a center temporarily to report back on whether or not he finds it to be an acceptable match []

I think Doc will agree about what I've said here due to the fact that he has personally heard my Chorus/Academy/Chorus soundstage and he realizes that the timbre match is not good.

lol man, that's harsh! It's just not a perfect timbre match - doesn't mean it's "not good"... []