DIY Klipsch Heresy Baffle Seal

10 Sep

In light of the recent coverage on Klipsch Heresy capacitor replacement, I’d like to follow up with an even easier upgrade for your compact, sealed wonders that costs about $5 and takes less than 5 minutes to install.

Let’s first look back at the term “sealed.” The Heresy got its name because it was such a radical departure from the previous designs of Paul Klipsch, which revolved around large, ported cabinets, 15″ woofers and folded bass horns to improve low frequency response. With the Heresy, Klipsch broke many of his own design principles, achieving quality, full-range sound from a relatively small, sealed enclosure, housing a front-loaded 12″ woofer.

Now I can’t speak for the second and third generations of Heresy cabinets, but the original boxes have a removable rear panel, secured with eight Philips head wood screws. The panel simply butts up against a 3/4″ strip of wood around the perimeter of the box interior. While this does secure nicely when screwed down tightly, I’m skeptical of the wood on wood air tight-ness–an important detail for a sealed speaker design to adequately reproduce low frequencies.

Here’s the part where you go to the local hardware store and pick up some foam weatherstripping like you would use to eliminate drafts from door jams and window frames. You’ll need at approximately 136 linear inches of the stuff (11′ 4″) to seal one pair of speakers. It comes in several different widths. I chose the 1/4″ variety, which in reality is closer to 1/3″ wide. If you wanted to really go for overkill, you could spring for the 1/2″ or 3/4″, but the wider you buy, the more you should plan to spend. It does spread out in width a bit when compressed, so I feel the 1/4″ stuff does the trick. It also fits nicely between the edge of the cabinet and the existing screw holes.

Application, just pull the tape off the adhesive backing, apply a strip of the weatherstripping around the perimeter of the cabinet and replace the rear panel.

Don’t expect a night and day difference, but those who know the Heresy will welcome any help in the LF department. The expansive properties of the foam also apply pressure against the back panel, helping keep the screws tight and eliminating possible vibrations and rattles in the rear baffle.

Just another step to ensure your Klipsch Heresy speakers are operating at their highest potential for many more hours of listening pleasure.

Klipsch Heresy “Type E” Capacitor Replacement

8 Sep

Eight years ago I picked up a beautiful set of Klipsch Heresy speakers.  My dad used to sell hi-fi in the 80s and one day an old friend and former customer called him up to say he was moving to Florida and letting go of his stereo (apparently they don’t allow nice stereos there).  We went over to his house and auditioned what he had, which included this first generation Klipsch Heresy pair.  After a brief listening session I couldn’t help but take the speakers home with me.

There are some fairly heated debates among hi-fi buffs over whether or not the Heresys are worth a damn. Some listeners hate them, some love them.   I happen to be in the latter camp, so I’ve toted them along from place to place, most recently in my cross-country move to Montana.  They always manage to find their place in my primary listening system, driven by a Kenwood M2A at 220 watts/ch.

With a manufacture date of sometime in 1980, these particular speakers are now 33 years old.  They have been well cared for throughout their lives.  The cabinets are in excellent condition and all the drivers are original, with the exception of diaphragm replacements in both K-77 tweeters.  I had one die on me a couple years ago and opted to replace the HF diaphragms in both speakers for sonic consistency, with genuine Klipsch parts, of course.

Even when well cared for and used properly, the capacitors in the crossover network are bound to fail to some extent over time.  The “Type E” crossover network found in Klipsch Heresy speakers up to 1982 consists of two capacitors, two transformers and a wiring block.  All capacitors have a lifespan.  While in a few rare instances they die suddenly when overdriven, they usually tend to drift off spec with age.  Of course, as the caps drift off spec, so does the sonic character of your speakers.

Mine seemed to sound fine, but I figured they deserved some maintenance after several years of faithful service.  I’m a bit of a novice when it comes to replacement of electronic parts such as this, so I didn’t feel comfortable sourcing my own capacitors.  Luckily, a gentleman by the name of Bob Crites has replacement kits available on his website.  Within a few days I had four caps and a wiring diagram on my doorstep.  Time for some fun.


It’s pretty easy to remove the crossover, or “balancing network,” as Klipsch calls it.  Loosen the screws on the wiring block for the three pair of driver leads and the rear panel input, remove two screws for board the x-over components are mounted to, and the whole network comes right out.


Isn’t that steel label plate cool?  The two old capacitors are those oil-can looking things, located top center-ish on the board.  Note the rust starting to build up on the outside–yeah, pretty old.  Just clip the leads, unscrew them from the mounting plate and you’re ready to install the new caps.  Along with new Sonicap capacitors (rated at twice the voltage of the original caps), Bob also includes mounting blocks and zip ties, leaving you with everything you need to complete the task minus some solder and an iron.  Mount the new caps, consult Bob’s included wiring diagram (or take detailed pictures of the crossover before you remove anything), sling some solder and there you have it.


It took less than an hour to pull and update and reinstall the crossovers for both speakers.  Not a bad Saturday project–plenty of time left over for a bike ride, a drink or an extended listening session with your refreshed speakers–or all of the above.

Let me take a step back and say that I had no proof my old capacitors were “bad.”  Again, bad caps can continue to work, just not to their original specifications, so even though my speakers seemed fine, they may very well have strayed from their original sonic signature.  My personal stash of electronic testing tools is limited to a couple of multi-meters, so there was no scoping to be had.  However, I do own a cheap Dayton EMM-6 measurement microphone, a USB audio interface and a computer.

Before I even unhooked the speakers for their surgery, I downloaded a trial version of FuzzMeasure and set up a little measurement rig.


While the angle of the photo is a little misleading, I placed the microphone so its capsule was one foot off the grill, pointing about halfway between the tweeter and woofer–pretty much right at the K-55 midrange driver Klipsch lovingly named the “squaker.”  I put some tape on the floor to make sure got things back in the same place for my post-installation measurement.  I measured the speaker, swapped the caps as described above, then measured again.  Below are the two measurements overlayed.


As you can see the response stayed more or less the same.  A slight gain in HF output and a little change in the transition zone between the LF and MF drivers.  Of course these measurements aren’t perfect, but it is nice to have a visual representation.  But do they actually “sound” better?

Verdict: Experiments like this are often hard to judge.  You’ll read all sorts of ambiguous adjectives when looking at others’ accounts of capacitor replacement.  “The soundstage was vastly improved.”  “A sparkle was restored that I hadn’t heard in years.” “I discovered a 4th dimension after replacement.”  Yadda, yadda, yadda.  While I cannot say right off the bat this “upgrade” drastically changed my speakers’ sound, I can say the project was greatly rewarding.  These speakers have been with me for many years and have never let me down.  Day after day, night after night they enable me to listen to music.  If nothing else, this endeavour is an insurance policy that our relationship will last many years more.

Plaid Dragon – “SoND” Live @ Gillioz Theatre

26 Aug

Springfield, MO has an excellent music scene. The Bootheel, Someone Still Loves You Boris Yeltsin, The Spacetones, Lilly Bee & The Pollinators, Knife Death, Delta Sol Revival, Kids & Chemicals, Speakeasy, Ryan Spilken–I challenge you to find a Midwest college town, or even a larger, more mainstream market, with a music scene as delightfully diverse.

Before leaving Springfield and the Gillioz Theatre, where I hung my hat for many shows, I had the pleasure of working one last concert. Fittingly, the event featured SGF’s own Plaid Dragon playing by themselves, in my favorite “an evening with” fashion.

This show would be the final installation in a series conceived over a few porch beers by Gillioz media czar/talent buyer, Vance Hall, and I aimed at featuring local performing artist known as “First Firday Live.”

I handled the live audio production for the event, mixing FOH and multitrack recording straight to Logic from the Gilly’s Midas Verona 400. I used the direct outputs of each channel of the Verona to feed the line inputs of a Mackie Onyx 1640 for analog-to-digital conversion into Logic over Firewire. After the show I turned the tracks over to Plaid Dragon’s synth/guitar player, Sam Gibson, for a final mixdown.

The show was bittersweet, but 100% Springfield, Missouri live music. I could not have picked a better send-off from the town and venue that will always be “home.” Please enjoy a video featuring Sam’s mix of Plaid Dragon performing “SoND.”

Home Studio: Make It Happen

25 Aug

The decision to move 1300 miles for a new gig came with a good share of challenges.  MSU wanted me to start work as soon as possible and to expedite the move they offered me the option to rent a readily available, on-campus apartment in family and graduate housing.  The dwelling leaves plenty to be desired.  It’s about half the square footage of the house I moved from, but only a 3 minute bike ride from work, utilities are included and I won’t have to worry about snow removal come Winter (a big, big plus).

I moved in with the notion this would be a temporary fix until I could find a house with more space for my various projects and interests.  Operating under this idea, I avoided getting too comfortable and setting up my home “studio.”  Though the more I live here, the more I realize how much the space works for my current situation.  Time to get comfortable.

Before leaving Springfield, I sold most of my furniture, including the desk that was the center of my creative space.  I don’t really have a vehicle fit for hauling furniture, and do anticipate a move at some point, so for now I’d like to avoid collecting more baggage.  But I can’t go any longer without a place to mix.  Just make it happen.


Barely an hour of my time in the extra bed/storage room, some spare pieces of garage shelving and I’ve now got a place to mix and work on recording projects.

The motive behind this entry is to encourage anyone else looking for reasons to put-off building their home studio, or other creative workspace, to just go ahead and do it.  Those excuses are just another thing standing between you and dreams.  If you can’t exercise your talent, you’ll never reach your potential.

Sure, my setup leaves a lot to be desired–tiny room, zero acoustic treatment, extremely un-ergonomic desk/chair combo (see camp chair in photo)–but it’s my space.  The more I use it, the more it will improve.  And if you can practice working in less than ideal circumstances, just think of what you can pull off when the odds are in your favor.

Bose 1800 Amplifier aka Carver pm1400

22 Aug

The arena I work out of, the Brick Breeden Field House, has a fairly sizeable Bose (yes, I know) sound system.  I’m not going to get into specifics of the install, because it’s really nothing special.  However, one aspect that did impress me was the amp rack–a stack of ten Bose 1800s.

Image From what I can tell, this amp rack has rarely been powered down since installation.  These babies have been running for a solid 15 years and still function as designed.  Mentioned in previous posts, I’ve been cleaning out our tech storage areas and continue to find all sorts of goodies from previous installs.  In my findings have been several Carver professional amplifiers, including a pair of Carver pm1400s.


Now look at the above pictures and tell me the Bose 1800 and Carver pm1400 aren’t the same amp with different branding.  Turns out Bose subcontracted their amplifier production out to Carver for their professional systems at the time.  It seems the only real difference is the Bose version has an EQ module installed for use with their Panaray speaker systems, which can allegedly be bypassed for use with other systems.

At 450 watts per channel into 8 ohms, these are not wimpy units, and workhorses to boot.  For this post, I suppose the moral of the story is don’t judge a book by its cover, or in this case hold a prejudice against gear just because of a brand stigma.  Side note: such a prejudice getting lifted can be seen in the case of the Behrigner X32, with so many former haters now finding themselves behind one.

That’s all for now. Maybe I should go clean the fans in those amps.

Community XLT41 & XP502 Woofer Replacement

19 Aug

Once upon a time there was a dealer that loved selling Community loudspeakers to MSU Bozeman.  Long throw, 3-way mid/hi horns, “full-range” weatherproof public address units, portable monitor/utility speakers… the university bought them all.

The latter units still see regular use.  My department owns a pair of XLT41 12″ 2-way boxes and a pair of XP502s, also 12″ 2-way boxes (though I’ve only seen one of them, the other is still exists only in legend).

Both models are very similar, featuring bi-amp capability, NL4 interconnects, black carpet finish, pole-mount sockets and a form factor that allows them to be used as stage wedges.  The main difference upon visual inspection is the HF section.  The XLT41 features a “rotatable” (see also: square) 90×60 degree horn while the XP502’s horn is a rectangular, 90×40 degree.

In my last post, I mentioned my ongoing quest of testing the department’s tech inventory to get a better handle on what we have to work with.  Well, I already knew one of the XLT41 boxes had a non-functioning woofer.  Funny story, during my interview, they staged a small “practical” for me to participate in, which consisted of setting up a portable PA system in a presentation scenario with laptop, microphone and projector.  After completing the task and firing up the system, I noticed the woofer was out and informed those overseeing.

Now that I have the job and the woofer is still not functioning, I pulled it out, took a meter to it and lo and behold I metered nothing–an open circuit.  I took the woofer back to the office and started looking for a recone kit or replacement driver.  After typing in the numbers listed on the magnet, I realized the XLT41 and XP502 share the same woofer–which would explain why their performance is so similar on paper.

Given the XP502 is currently missing its significant other, I opted to pull the working woofer from it and drop it in the XLT to give us a matching, working pair.  Now, one detail confused me a little.  While looking at the spec sheets for each box, the nominal LF impedance was listed as 8 ohms.  However, the sticker on the woofer says 4 ohms.  This was discrepancy consistent between all woofers.

Here are the boxes next to one another, woofers out.  XP502 on left, XLT41 on right.


While I had the grille off, I figured I’d go ahead and use that “rotatable horn” feature of the XLT41.  The horn had been set up so that the wide dispersion was in the horizontal plane when being used as stage monitor, on its side.  I’d say 95 percent of the time it’s getting used on a speaker stand, so I turned the horn to get that 90 degrees of horizontal dispersion when upright.

By this time, I’d spent enough time with these speakers that they were growing on me.  Yes, they’re cheap boxes in the scheme of things, but they’ve obviously served their purpose over the years, fulfilling the needs of many, many events, all the while holding up to the abuse of tired student workers packing them up after long Friday night shifts.  Though, I will say I discovered a new level of cheap manufacturing when I pulled out that horn.


Notice the horn doesn’t actually have bolt holes for the driver.  Instead they opted to glue some pieces of fiber board to the horn, staple on a baffle and bolt the horn to it.  The staples were starting to pull loose, so it was only a matter of time before the driver fell off on one of those late-night strikes.  I grabbed some wood screws and secured the baffle back to its counterparts.

The XLT41 now has a working woofer.  Though I should still pull the horn out of the other box and reinforce it, as well.  Now regarding the empty hole in the XP502.  It seems Community no longer has parts for this 11-year-old box, but I do know from the sticker on the magnet the speaker is 4 ohms and was manufactured by Eminence.  Perhaps this replacement will do the trick.  Edit: I had inferred parts were unavailable judging by info from Community dealers on the web, however a quick call to Community support revealed that parts are indeed still obtainable.  A replacement woofer is $141–a bit pricey in my mind, but at least I know I’m getting the real deal.


31 Jul

I usually reserve this place to talk about gear, production and all the rest like that, but I must interrupt with a quick shout out and much love to my friends in Team HJ who joined me for seven days last week in the Des Moines Register’s annual great bike ride across Iowa (better known as RAGBRAI).  

I find few things as freeing as waking every morning with nothing to do but ride your bicycle.

Ride on, friends.  


Treasure Hunting

31 Jul

With football season fast approaching, my morning was full of production meetings to prepare for what’s to come. While such meetings are no doubt important, by the end I was ready to get my hands dirty with some tech. While de-prepping an event a couple weeks ago, I had noticed a closet outside the stadium’s control booth full of tangled cables and seemingly random pieces of gear, so what better time than the present to see what was hiding in there.

An hour later, I had filled a cart full with DVD players, DSPs, amps, wireless receivers and more–all in unknown condition. Jackpot!


After admiring my bounty, I grabbed a countertop, claimed it as my workbench and happily spent the rest of the afternoon testing all the gear, labeling each with its current condition and date of testing.

Tomorrow I hope to assimilate the working units into our inventory stored in the arena and begin developing a more comprehensive list of what we have to work with. Baby steps!

Here’s a shot of easily the coolest thing that turned up, an Altec 1592B mixer/amplifier.


QSC 1400 overheating at the new gig.

15 Jul

Hey there, trusty followers.  I’m sure you’ve been on the edge of your seat since my last post in…. uh… well, too long.  A lot has happened.

I’ve relocated to Bozeman, Montana to take a gig as Technical Director of Sports Facilities at Montana State University.  Yes, that’s a bit of a mouthful, but I’m excited for what the future holds.  I can’t say I could have predicted this move, but what the hell, sometimes you feel like getting a little crazy.  I’ll give you the rundown on this in a future post.  I promise it will be soon-ish.


Looking out my front door.

Anyhow, the second day on the job, a set of speakers in our arena, aimed directly at the court, purposed primarily for our basketball team (go Bobcats!) to crank their warm up jams(z) through, was cutting in and out.  We were listening to the radio at the time, so someone suggested perhaps our tuner was just losing signal.  However, only the one zone was being affected, so I greatly doubted that was cause.  I nodded my head and tried to keep an open mind, but kept thinking in the back of my head, “we’ve got an amp overheating.”

Sure, it could have been lots of things, but the overheating hypothesis just felt right.  Music would play through the speakers for a few minutes, then shut down for about 1/3 less time than it had played.  So a minute and a half-ish of playback, 30 seconds-ish of death. Give or take an ish.

Upon a visit to the amp rack, what else did we (my comrade Tom and I) find but a little QSC 1400 that was hot as Hell.  We were in the middle of something, so we shut down the amp, put a fan on it and went back to taking down some soft goods, figuring we’d troubleshoot when we had the time.

I used to have a QSC 1400, or rather “borrowed” one from my dad, and I was fairly positive they were forced-air cooled.  Today I had an extra hour to squeeze behind the amp rack and point my flashlight at the back of the amp.  Yep, there’s a fan.  And yep, upon powering up the unit, the fan didn’t budge.

I really love fixing broken audio gear, so I ripped that baby out of the rack faster than you can say “thermal meltdown” and pulled off the top.  HOLY CRAP–the fan was absolutely covered in black, super-dust gunk.  Of course, I was so excited to clean the thing at this point I forgot to take a picture.  I immediately removed the fan and started to flush the motor with WD-40.  The fan was still quite difficult to turn by hand, and wasn’t even close to moving on its own accord.

It took a full disassembly of the fan motor to clean out all the crap.  I reassembled the fan, put the fan back in the amp, the amp back in the rack, and got the jams(z) once again pumping.

While I completely understand how such a task can be overlooked in a fast-paced, event-driven environment, try and make a point to clean your amplifiers’ cooling systems, at least once every, oh, decade at least.  And if you’ve got amps fancy enough to have filters, don’t forget to clean those–I’ve seen a few too many filters full of “dryer lint.”  Great for campfires, bad for amplifiers.

I leave you with an interior shot of the QSC 1400, post fan cleaning.  These are great little workhorses.  When cared for, they can provide clean, reliable power for years and years.


By the time this needs cleaning again I’ll be mixing FOH for Peter Frampton.

Women’s History Month @ First Friday Live

19 Mar

The dream team is at it again.  Ben Clayton (with additional camera support from Bret Hoy) and I, put our expertise together once again for the folks at the Gillioz Theatre to produce and document the March edition of First Friday Live.  Featuring three Springfield based, X-chromosome-centric musical acts, The Eskimo Girls, Black Bonnet Ballyhoo and Lilly Bee & The Pollinators, the show was sponsored by Missouri State University in honor of Women’s History Month.

This morning I received the highlight video and couldn’t resist sharing.