Rebuild Heresy for more bass?

[Mark Dyrbye]

I would like to improve a set of 1975 "unfinished" Heresy speakers with the 10 inch woofer to get lower bass. Has anyone done this or does Klipsch have some dimensions to try? I am prepared to build new enclosures with rounded edges, internal bracing, etc.

The current inside dimensions are 11" deep, 14" wide, and 20 " tall. My first thought is to make them deeper, and possibly taller, to get the horns to ear level when sitting. Years ago I added a 12 inch base to them which helped very much.

Also, I am wondering if aligning the drivers would make a difference, particularily the mid and high horns.

[soundog]

Speaker components and their cabinets are carefully designed to optimize the sound. Changing dimensions might actually produce an inferior sound. Heresys are terrific speakers as the are. Adding a base was a good idea, however, I would think it would be better to add a high quality sub to extend their lower limits.

------------------

Soundog's HT Systems

This message has been edited by soundog on 02-20-2002 at 08:04 AM

[Mark Dyrbye]

Hi Soundog, thanks for your response. I will agree that the Heresy is a good speaker, as I doing some extensive shopping to replace them, when I decided to take my old CD player (1979 Carver) to an Audio shop to compare it to an Audio Note DAC 1.1 that I had been impressed with earlier. The short story - I bought the later version of Audio Note DAC kit 1.2 and wow, the Heresy's sound so much better! The bass is now tight, the transients on any notes are immediate, the definition of instruments vastly better, and so on.

So now I am trying to improve the Heresy's in whatever practical ways possible. From the BB archives I have read about the P-trap (the squawkers are K-55-V), the crossover improvements, etc.

But I sure would like to explore the lower bass question further. Anybody else checked the technical possiblities? Thanks so much for your help!

[soundog]

Yea, Paul Klipsch and his team of engineers. Every design involves compromises. The Heresy is a compromise. Lower, clearer, more dynamic bass is avilable in the Klipschorns and some other folded horn designs. It is IMHO the best, most true to life bass attainable. However it requires a big heavy enclosure and some solid corners w/o obstructions.

A more practicle version of this design would be the LaScalas that don't require a corner but sacrifice some bass in the lower register. PWKs Heresy design sacrifices some of the clarity, realism and lower register in favor of a smaller enclosure. Because PWK beleived that the only way under the law of Physics to get real bass was the folded horn he named his non-folded horn speaker "the Heresy". He did the best he could with this design.

Every raw speaker has a set of specs that when fed into a computer (PWK probably used a slide rule and a pencil) yields optimum enclosure size for that particular speaker using one or more enclosure designs. I'm sure PWK optimized conditions for the speaker in the Heresy given the requirement that it not be a folded horn. That's why I'm sure you would have a near impossible time doing any better and it would be a very good bet you would do worse.

Modern speakers have acheived lower base using a number of alternative designs but while some go lower than the Klipschorn none are as true to life IMHO.

Sub woofers designed using space age materials and very powerful solid state amps AND LIMITED TO A VERY SMALL FREQUENCY RANGE have been able to produce some powerful low bass ideal for Home Theater. But would you be able to tell how distorted a sound effect such as an explosion or other noise might be? Would you care?

I have tried subs with my Klipschorns and they take away more than they add IMHO so I never use them with music, only for the LFE efffects in action movies.

However some owners of both LaScalas and Heresys have discovered some very good subs that are a very good compromises to a Klipschorn. They are not cheap but you can search this site or post a questions and you will get plenty of suggestions. I like the LH10s but I have read that the Reference subs are very musical but not as good as some on explosions (again a compromise which I happen to agree with).

BTW, P traps are not necessary on all K55Vs and yes many including myself have found that crossover upgrades can result in some improvement in clarity and "smoothness".

As you have already discovered, the Klipsch Heresy speakers are very true and revealing so the better your source components the better they sound. Many on this site (and other sites) have found that the addition of tube preamps and/or tube amps have produced great results.

Best Wishes in your quest for better sound. It's a great adventure. Keep asking questions - there is a wealth of knowledge (and a little BS) on this site.

------------------

Soundog's HT Systems

This message has been edited by soundog on 02-20-2002 at 08:08 AM

[Chris Robinson]

You might wish to do a search on contributions by "Jon M" ... He put an AR woofer (if my memory is correct) in his Heresies and really liked the result. Think it was back in the fall. Anyway, what he did was well-documented (he's an engineer's engineer).

------------------

If you don't like what is coming out, you wouldn't like what is going in." -PWK-

---------------------

HOME THEATER

Klipsch 1968 ALK Cornwall "II"s (LF/RF)

ALK Belle Klipsch (Center)

Klipsch Heresy (RR/LR)

Klipsch KSW-12 sub

Sonic Frontiers Anthem AMP1 (driving Cornwalls)

Sonic Frontiers Anthem AMP1 (driving Heresy's)

Denon AVR-4800

Toshiba SD-3109 DVD

TWO-CHANNEL SYSTEM

AES AE-25 "Superamp"

AES AE-3 Pre-amp

New Tube 4000 CD Player

1976 Klipschorns (ALK'ed)

[Ninja Nate Z]

Yes, we all well know the intricate miracle of speaker design is something that we mere miniscule mortals are not capable of achieving, but I think this thread was started with the intent of "FINDING OUT WHAT OTHER PEOPLE HAVE TRIED AND IF IT DID/DID NOT WORK FOR THEM AND ANY RECOMMENDATIONS THEY MIGHT HAVE AND/OR SUGGESTIONS"

That said, I have a set of beat-the=hell+up heresy II's that I would like to modify extensively, perhaps even forming molds and using concrete as walls, who knows, so any advice given would be more than welcome.

[JonM]

Chris -

Thanks for the kind words - I guess being an "engineer's engineer" means tinkering and playing! It was an Advent woofer, and it was an experiment. It worked, sort of. I've heard tons of commercial speakers with a better bass/mid blend than my Heresies had with the Advent woofers (no surprise - I really was just playing around). But they did have a low end that stock Heresies don't. The Heresy cabinet is about the right volume for a woofer like the Advent's - getting that blend right with the midrange is the challenge!

My restored-to-stock Heresies are for sale. (My K-horns get all the attention, and the Heresies are getting lonely :-) See separate note for details & pics.

[jerohm]

quote:

---

Originally posted by Mark Dyrbye:

I would like to improve a set of 1975 "unfinished" Heresy speakers with the 10 inch woofer to get lower bass...

Years ago I added a 12 inch base to them which helped very much.

---

I'm confused. I thought Hersey's originally came with 12" woofers. In any case, Eminence Alpha-12 would be a better match than the less efficient Advent woofers. Increasing the volume of the original cabinets will help with the bass. In many ways that is exactly what the Forte I is to the Hersey II.

This message has been edited by jerohm on 02-23-2002 at 11:58 AM

[Malcolm]

Just to set the record straight, Heresys do have 12" woofers.

I think the simplest, and best, solution would be to add a good subwoofer to your system, especially if you ever intend to use the Heresys as part of a HT system. I have a Decware WO32 that pretty seamlessly extends the bass quite a bit. There are a lot of other good options for a subwoofer, mostly non-Klipsch, as the powered subwoofer forum reflects.

If you are really intent on modifying your Heresys for more bass, you might want to look at the specs for some of the other Klipsch speakers that use the same tweeter and squawker driver for ideas. But I think you will probably have to at least replace the woofer and make some minor crossover changes to make the result sound right. I think you would probably have to build something like a Cornwall to get what you are looking for. And its already been done by Klipsch. I think it would be much simpler to buy a set of used Cornwalls, or other Klipsch speakers with more bass, and sell the Heresys, even if you still build new cabinets.

If you do decide to modify your Heresys, let us know what you do and how it turns out. Good luck!

[Klipschguy]

Heck, if your considering building a new box for the Heresy drivers, how about building a folded horn for the bass section? Maybe the University Classic? A W-bin would probably even work. The low frequency cut off is largely determined by the horn rather than the woofer size. I'm sure John Warren would know if the Heresy woofer would work in a folded horn application. Pretty radical, but just a thought.

Warmest regards,

Andy

[Mark Dyrbye]

Say, all the responses are great!

I have done a lot of reading of old threads since I started this one, so now I have much more insight into what fellow Heresy owners feel about their speakers and what tweaking is likely worthwhile.

Regarding the 10 inch or 12 inch size of the woofer, I had measured the baffle cutout, which is about 10 3/8 inches, so I mistakenly declared it to be a 10 inch woofer.

When I opened the enclosure and saw how small the volume is for the size of woofer, and how the two horns and crossover take up a fair bit of space, my first reaction was, hmm - lower notes cannot be formed in such as small sealed box, can they? So, I thought why not throw out the question to Klipsch as they must have made some tradeoffs to keep the size down. When I went to the Web page to find the email address, I noticed the forum, and rather than do the hard work of researching and reading, why not just throw out the question and see if someone has done some enclosure mods.

Now that I have improved my music source with the Audio Note DAC, the Heresy's sound much better and so much tighter. I have to revamp most of my old stereo, and have a upgrade plan. But the Heresy's are certainly worth upgrading - the two issues I have with them are the lack of low bass, and the "horn glare" or whatever I am hearing on intense higher notes which bothers me.

Anyhow, I absolutely appreciate the feedback I have received so far.

Mark

[Malcolm]

Check the archives for Dynamat/Moretite tweak for the horns. Or, you might just try turning down the treble, if you haven't already tried that.

[soundog]

I must be missing something here. Bass can not be formed in a small box? What about all the acoustic suspension designs such as the AR-1 & AR-3 so popular in the 60s. Or for that matter the KLH and Advent designs that followed. They were noted for the deep bass produced in a small enclosure. The acoustic suspension designs used a small sealed enclosure to act as a "spring" - compressed air pushed the cone back - expaned space pulled the cone back because of the slight vacuum created. A bigger enclosure might actually lessen this effect and reduce bass - the design involved the optimization of speaker with the sealed enclosure. Therefore, if you put an acoustic suspension speaker in a bass reflex enclosure it would sound poor because it depended on the acoustic "spring". Now if the Heresy's enclosures are not rigid enough that could be a good mod as would be metal horn dampening or a "p" trap if the driver is one of those one in five K55Vs that needs it. Anyway this is how I understand it, if I'm wrong I wait to be enlightened.

------------------

Soundog's HT Systems

This message has been edited by soundog on 02-25-2002 at 12:08 PM

[JonM]

Soundog's right. I used the Advent woofer because it fit (same screw holes and everything) and because I had a pair lying around. The Heresy cabinet is about the right volume (i.e., about the same volume as an old larger Advent), and the fact that it isn't as rigid or air tight as it should be didn't stop my experiment. I dropped the mid/high output by changing the autoformer connections - made for a better balance with the less efficient acoustic suspension woofer.

The result was okay, but hardly great. I got more lows, but the midrange blending wasn't as good as it could have been. I didn't try too hard playing with different crossovers (the choke and capacitor in the woofer circuit will affect things a lot), and I didn't go out looking for other woofers (I was playing around and didn't want to spend anything if I could help it).

But that's one beauty of the Heresy - you can get inside so easily to play around. A fun way to experiment and learn.

[Malcolm]

Villchur certainly proved you can get low bass from a small box in 1954 with the AR-1, which used acoustic suspension. The Heresy also uses acoustic suspension. The issue is the match of the woofer parameters to the volume of the box, which is fairly critical. A different woofer may require a larger volume box, or a smaller volume box.

BTW the Heresy box isn't really as leaky as it seems, although it could certainly be improved a bit.

As soundog points out, a woofer designed for an acoustic suspension cabinet won't necessarily work well in a reflex enclosure, and vice-versa.

As JonM points out, there are tradeoffs when swapping woofers. He lost efficiency and has crossover issues.

[Manuel Delaflor]

Mark,

I see two paths, a hard one and an easy one. The easy is to just add a sub, like a Sunfire (which by the way produce enormous amounts of bass from a REALLY SMALL box, but that's another story). The other way is to make new cabinets for your Heresy's, of course you need lots of calculations to do it right, but in principle is possible. I think the answer lies in the time and dedication you can give to your needs.

[SOUNDJUNKIE]

Mark, I helped my brother-in-law purchase these exact speakers some time back and he reported the same problem. Try porting the rear/bottom corners of the cab and install vents. I figured it worked well with small monitors, why not some larger limited LF speakers, it worked.