Rebuilding Heresy's - - - Please read and be gentle!!!

[boonaroo]

I am new to building speakers , but I am ready to give it my best effort. I have built furniture before and have access to a complete woodshop, so having proper equipment won't be a problem.

So here is what I would like to try as my first speaker building project. I picked up a very good pair of Klipsch KMS stage monitors for a bargain price of $5 for the pair. These look exactly like Heresy's minus the tweeter. I have removed everything from the cabinets, cleaned them up, and both the woofer and midrange horn work perfectly.

I removed the crossover, which looks impressive, but I have no idea about reusable parts.

Instead of trying to scavange from them, I took advantage of Parts Express free shipping and have these things on the way:

260-235 50 Watt Control Panel
270-050 Pioneer AHE60-51F 3-1/2" Horn Tweeter
260-210 Crossover 3-Way 8 Ohm 800/5,000 Hz 100W
260-309 Gold Speaker Terminal Rectangle

The control panel will be used for balancing the horns, the Pioneer tweeter has good specs and hopefully it will integrate well. As I said, I know nothing about building a crossover, so I went with one that had cut offs similar to specs I researched on Heresys. The terminal box speaks for itself.

I would like to build a floor standing speaker with enough volume to allow the woofer to overcome the Heresy's limitation on low end extension. A ported design would be fine if it will improve performance.

Here are some crude paintshop drawings of what I am thinking.
Front

Topview

I will be using 3/4 MDF and plenty of bracing. I don't know how I will finish these yet, but I am thinking a black piano finish.

These will be a gift for my father-in-law so I want them to be something he will cherish and use.

Thanks for reading this longish post, and I look forward any of your comments and help. Remember I am a speaker building novice, so go easy on the technical terms.

Kendal

[Groomlakearea51]

Welcome to the Forum. You might have problems with the crossover points vs the size of the cabinet, etc. Check with Bob Crites (BEC) as it may be better to use the current crossovers (with new caps and possibly a different crossover point). The Heresy-II drivers were designed for a specific cabinet volume, and the crossover points are 700 Hz and 6000 Hz. As far as experimenting, why not!! That's half the fun!!! Good luck and tell us how the project comes out at some point.

[colterphoto1]

arrrrggghhh, which KSM monitor cabinet did these come out of and what are the part designations on the Klipsch components? Those look like K43 woofers and K58 mids which have the same horn as a Cornwall. Those are some great stage monitors,we call them the 'drummer's dream' because they kick so hard. The K58 extends very high and there is nothing in the network to filter out the high end. I've used the KSM2 as main speakers because of their frequency response. If these are the smaller KSM1 they are still great speakers. In any case the higher wattage woofers sometimes don't go as low as their residential counterparts and that could be an issue with your cabinet design.

If you are definitely going to build some type of tower cabinet, an easy design ploy is to stay within 10% of the original interior volume in the cabinet and maintain the same port size (port has volume, not just two dimensions).

Or go to one of the guys here with box building programs and get the T/S parameters of the driver you have.

I would NOT change the network other than to perhaps add the HF section which can be as simple as a capacitor and choke (perhaps another resistor to pad down the output).

[Groomlakearea51]

As Colter said. Stay within the same volume more or less.[Y]

[boonaroo]

If I was to use the existing crossover pulled from the cabinet, help me design a high freq. filter that I can integrate to the same board. Remember, I am a novice. I know that I can rewire the crossover to accept a single input, but from there I would be lost.

Again, thanks for your help.

Kendal

[colterphoto1]

without a test facility it's tough to design sight unseen (unheard).

First- what components exactly do you have?

[boonaroo]

Well, I don't have one available, so I will have to experiment with what sounds best to me.

I should be getting the tweeters in today, so I am going to do a test run in the front baffle that I have built. It won't be in a sealed enclosure, but it should give me an general idea about where I am going.

The crossover from PE seems to be of average quality.

More to come later.

Boonaroo

[boonaroo]

I checked out the tags on the woofers and they are K42's. From what I have read this is a more robust woofer that was used in stage monitors and cinema speakers.

The mid horn is a K59K. I haven't done any research on them yet.

Where can I get the specs on the k 42 so I can better design the enclosure. I still want them to be a floorstand speaker about 40-42" tall.

Thanks,

Kendal

[colterphoto1]

K42's are a pro Heresy woofer, I don't think you'll be squeezing much low bass from them. They're designed for punishment, not deep LF.

K59 is long obsolete, it's replacement is the K52KP. I'll surmise from your components that you have the parts from KSM-12 monitors.

[colterphoto1]

Here's the spec sheet on the speakers that those components came from.

KSM-12 &15.pdf

[boonaroo]

Thanks colter. It looks like I may be out of luck getting much LF extension out of the K42's. I guess that I should rethink my design. Do you know where I can get the TS parameters?

Another thought is using a pair of JBL 123A driver. That might not be the best thing to suggest around here.

Thanks for the help.

Kendal

[Marvel]

You are the second person who has talked about th JBL123 woofers. They should work well, but they don't really need a very large cabinet. You would definitely get lower bass out of them, with sn Fs of 25Hz.

Bruce

[Rockets]

Since my K-24's were blown I went with the JBL 2213H woofers (higher watt replacement for the 123a ) and ported the boxes. The good news is you will get lower frequency extension. The bad news is, the Hall effect I've encountered at high volume. Most noticable is the vocals. I've also heard the K-24 will also do this, but w/o one to plug in I can't give you a first hand account.

[PrestonTom]

Kendal,

Glancing at your comments, I am concerned about a couple of things.

First there are various descriptors that describe the electrical and mechanical properties of a particular woofer (T/S parameters) These in turn can be used to design the cabinet. Two very important design elements are the cabinet's volume and whether it should be ported (and how). These are not trivial issues. Fortunately there is free software that can help you get good first approximation of a proper cabinet. The folks over at DIYaudio forum do this regularly. The second thing is your comment about doing this "by ear". Let me steer you away from this notion. It would be a never ending cycle. You would get differences in the sound but it is unlikely that you would ever get their best performance. Let the software (or tables) help you out. One exception to this would be if you cloned someone else's design - if it was a tested and proven version. There are various threads in this forum that you can search. However, if you copy one of these, you need to do it exactly.

Good Luck,

-Tom

[TBrennan]

Hell Tom, this hobby IS a never ending cycle. Most of us old timers started DIY speakers by ear and I'd hesitate to discouage a fella on his first project by making things seem so complicated he might say "to Hell with it". Sure there are nice tools and resources out there now but they're generally more useful to the fella that's getting pretty involved, it's still possible to make yourself a pretty good sounding speaker just messing around with simple methods and acting on your own notions. And don't forget Berenek's Law.

Regards