Friday, December 7, 2007

Klipsch LaScala and Belle, original and modified

Due a series of posts on a Dutch forum, I remembered an interesting mod to the Klipsch LaScala. This is as good a reason as any to feature the LaScala in itself.

It came after the famous Klipschorn and was initially designed as a public adress speaker for an election campaign. It turned out to work well in the home as well, not requiring perfect corners for proper placement. Due to its simplicity, it was also cheaper to manufacture. Of course there is no free lunch, the Klipschorn has lower extension.

The LaScala was or is popular amongst first-time horn builders. This is not suprising when comparing the Klipschorn plans and LaScala plans. The LaScala has fewer parts and less extreme cuts.

There are several drawings floating around online. There are old drawings in metric measurements from a German source, apparently based on original Klipsch plans. I think I have seen English versions of this as well, in inches. Then there are newer private drawings, made by someone over at the Klipsch board. The Klipsch board keeps rearranging its messages, so my link is dead. They were very nice and insightful drawings, though. When I feel like it, I will dig in deep into the Klipsch archives and find it.

For DIY-ers, I link the German plans, from Audiotreff:

The Belle Klipsch is a squished version of the LaScala. It is essentially the same horn, but it is folded into its enclosure differently. As a result, the cabinet is wider and shallower than the LaScala. It makes it easier to place in the home. As I understand, Paul Klipsch recommended it as a centerchannel to use with Klipschorn. Mind that this was as a fill-in between stereo speakers that were spaced too widely apart. This was before surround sound. However, these days the Belle Klipsch is indeed used as a center channel (and surround channels) in surround set-ups with Klipschorns, as is the LaScala. There are private plans of the Belle somewhere at the Klipschboard, if you can find them.
Finally, we get to the thing that sparked this post. I read a thread on a Dutch forum about Altec Voice of the Theatre-like (VOTT) enclosures. These have a horn in front of the driver and a bass reflex box on the rear. One remark to another and eventually I remembered an interesting mod to the LaScala. It was pioneered by djk, who hangs out here and there on the usual high efficiency loudspeaker areas online.

It assumes that the driver is underutilized by the tuning of the horn and backchamber. By enlarging the backchamber (also known as 'doghouse' in Klipsch designs) and porting it, the cutoff is lowered. Note that this mod essentially turns the LaScala into sort of a VOTT, because the front of the driver is hornloaded and the rear is in a bass reflex box.

You can find more info about this mod at:

Wednesday, December 5, 2007

Next step in hornresp, contribution by Horst Möller forthcoming

Just wanted to let you know that the next step in the hornresp-series is coming up, planned for this weekend.

I have also had some contact with Horst Möller, a German horn designer. He uses some tricks to make very small backloaded horns. He has a cult-following and a counter-cult, so it will be interesting to read some of his ideas. We're not negotiating deadlines yet, we just agreed that he is willing to write something and I am willing to edit and post it. More info is forthcoming, in the meanwhile you can check out his designs here.

Tuesday, November 20, 2007

Monday, November 19, 2007

The Dino Horn

Something to break the Hornresp series.

This is a vintage design. It was featured in the Klinger loudspeaker book, and that's about all I know about its origins.

This picture comes from the World Tune website, an art project that travels around, placing these giant horns in large space or the open air to play soundscapes. Thanks to the persons in the shot, you can appreciate its formidable size.

A noteworthy feature of this horn, is its floor-firing mouth. Actually, the mouth is formed by the opening at the base of the cabinet, but the cabinet itself is firing downwards. This folding topology is used in the Edgarhorn slimlines and Seismic sub, as well as the older Monolith design. The classic Swedish Klason horn also has a down-firing mouth. By letting the mouth be part of the horn, the enclosure itself can be reduced, which makes the horn seem a lot smaller. Considering its current size, imagine what it would look like when folded in a more traditional way!

I can't find any listening experiences of it, but literally everyone that ever writes about it online is fascinated by it.

You can find the plans at Note they are all in metric.

Saturday, November 17, 2007

Getting started with Hornresp - #2

This time, we're adding a driver and entering the new driver's name and parameters. To get started, you must have installed Hornresp by now. If not, now is a good time to do it. When you are done, you can start it up and when it is ready for use, the screenshot below is what you will see:

Note that the software starts at a default screen, or a default driver and horn. If you want to work with other drivers, you can click "Add" to open a new section. I have marked it red in the above screenshot.

The resulting frame is given below. At this point, it is just a copy of the default frame, with all the driver parameters and horn parameters copied from the default. You can modify this new frame to the new parameters, without losing the default settings.

You can enter your own driver data, by selecting a field and typing in it. You select it by left-clicking it's textfield. When it is properly selected, it lights up blue.

In the following image, I have already changed the driver name (bottom of image) and now I have selected Sd, or driver surface area.

Finally, there may be some parameters that you don't know about your driver. Hornresp can calculate Cms, Rms, BL and Mmd out of other parameters. You can activate these calculators, by double-clicking on the parameter that you need to calculate. A small window pops up and asks you for one or two Thiele-Small parameters. Simply enter them and click OK, the calculator will produce the right value *and* enter it into Hornresp, then disappear. The calculator looks like this:

These are the basics for driver entry in Hornresp.

Wednesday, November 7, 2007

Getting started with Hornresp - #1

The first thing you do, is download it... Man, that's so bad. But as it's an essential step anyway, here's the link.

Next step will be entering driver data and simulating your first standard horn. This will feature screenshots of every step and location. I admit that it only starts getting interesting from there...

Saturday, November 3, 2007


Blogspot/Google suggests placing AdSense advertisements in your blog. Google makes money, bloggers get a financial incentive to create content, the readers get more to read. It seems a win-win situation. I looked into it, both for this blog and some other blog-activities I have running. The end conclusion can only be, that this blog should not, and will not be commercial.

This blog basically runs on theoretical and practical material that is published by horn enthusiasts and professionals online all over the world. Some of the best stuff that's out there, has been around for 10 years or more and came out of a desire to simply share information and turn people on to an interesting hobby. These days, everything looks flashy and makes the owner money, without actually offering much. Well that's an exaggeration, but you get my point.

This blog wants to bring together good solid stuff, whether published here or elsewhere, and get some of that horny caring and sharing spirit back. So I dig up interesting horn theory and context from all kinds of sources and present them here.

So. Most of it isn't mine and I fondly remember the day when people shared their hobby for free. Could I make money off it? Of course not.

The Hornloudspeaker Magazine blog will remain AdSense-free. Not a statement against AdSense or commercial blogging at all, but in keeping with the spirit of this blog.

Friday, November 2, 2007

Midrange horns/the Edgar Midrange Horn

The first annotated link. Starting with Bruce Edgar's midrange horn article in Speaker Builder Magazine (cover illustration linked from A famous horn-diy-er named Volvotreter has the article scanned and posted on his website. He has a lot more on there, both horn theory articles in general as well as spectacular projects of his own. I give you a general link to his website instead of links to all individual pages. His pages are worth a visit, you navigate from there. (scroll down to articles/the Edgar Midrange Horn)
In this publication from 1986, Edgar explores characteristics of midrange horns using cone drivers and arrives at strategies and guidelines for midrange horn designs. These are still the basis of his own product range, so heads up if you want to learn.
An interesting feature that Edgar refers to, is that you can tune the horn to give a different response characteristic. You can tune a horn to compliment a specific driver's response peculiarities. Given time and dedication, you can squeeze the most out of whatever potential your driver has.
Next time, a first episode in the series about Getting Started with Hornresp.

Wednesday, October 24, 2007

Horn Hits

I am still working on the infrastructure for this magazine, but I saw in the statistics of Sitemeter that this site is already getting quite a lot of visitors. From all over the world, as well. I am sorry that I aroused anticipation without delivering!

I am planning ahead some posts/issues. I am going for hard content, because there's already enough sites that link to sites that link to sites that link to sites.
  • I have noticed that first-time users of the excellent hornsimulation program Hornresp (by David McBean) often find it hard to get started, so I want to write a short tutorial, with some screenshots. This will start with your basic frontloaded horn, get to backloaded in a later post/issue and the series will probably end with tapped horns.
  • I am after permission to publish some famous patents and papers by the horn giants, on whose shoulders we (try to) stand.
  • I have invited one horn-professional to author on this blog, I am considering a few more.
  • Of course, any of you who showed an interest in this blog so far, is welcome to send in copy!

The copy deadline for the first issue is november 1st 2007, publication shortly thereafter.

Sunday, October 14, 2007


And bear with me, as this is my first attempt at editing and publishing a magazine. :)

Statement of intent

A blog about hornloudspeakers.

  1. Anything from all-horn multiway fronthornloaded monsters, to tiny single drivers in backloaded horns
  2. Tech stuff (theory, designs, plans, filters, calculators)
  3. Reviews (listening experiences and measurements)
  4. Lust (pretty pictures etc.)


  1. Periodical bigger features, like reconstructing a vintage design and simulating its response with modern drivers, or introducing a DIY-design by a contributor (hence the 'Magazine' in the title)
  2. Incidental, though possibly frequent shorter news flashes, like referring to an interesting new thread on an audioboard

Single/multiple authors:

  1. While this is a hobby venture of one person, contributions and collaborations are appreciated
  2. Contributors and collaborators can be both amateur and professional

External horn stuff:

  1. This magazine will support and endorse good external information anytime. Inform me, I will link to it!
  2. I have a large folder on my harddisk, with lots of horn designs and articles. Eventually, most will be posted here, but if you are missing something and need it quickly, you can ask about it and I will try to find it for you.