Sunday, December 28, 2008

Development Project

There are many things to consider when working on your dream loudspeaker system. Physics, technology, the cool factor. Another one is living around the thing. In my case, after moving to a new house, the system is proving too large to be practical. I am using LaScala bass horns (filtered to have flat response to 40 Hz) and horns with fullrange drivers for midrange and (some) treble. Due to the layout of the room, we have to sit pretty close and the integration between bass and the rest is hard. It also looks imposing and my girlfriend and I keep bumping into the things.

I have come to the conclusion that it's better to change my approach and my system. I'm looking towards cutting edge and vintage answers to this problem. Some of the legendary hornsystems were cornerhorns and some of the arguments for using corners were that they provide opportunities for excellent bass response and are convenient use of space. (See Klipsch for reasoning.) In my personal case, I only have one corner available and I am not about to go mono. Luckily, there's plenty of material that suggests that at a cutoff of 100Hz or below, it's impossible or at least very hard to locate a sound source, so going with something other than stereo below 100 Hz is OK.

Based on this, I have decided to take a new approach to my system. I will build a horn, to be placed in a corner, for frequencies below 100Hz and will have to stretch the mid/high sections' response down to that point. Exactly how, I don't know yet.

Now, a horn in a corner is still a wide concept. I can go for a frontloaded cornerhorn (Klipschorn, Jubilee, Hartsfield), a rearloaded cornerhorn (Jensen, Tannoy, Schmacks), I can stuff a tapped horn in a corner, I can design a frontloaded, rearloaded or tapped horn myself for in a corner. The DIY (do-it-yourself) and DIY (design-it-yourself) options sound good, so I hereby announce my horn design project.

I will have to work out parameters to work with. I need to decide on desired cutoff and acceptable size. We may simply end up with the conventional tapped horn coffin, but we might end up with something very different. Of course I have ideas cooking. One hint: think Olson...

Thursday, November 20, 2008

Thread on Klipschorn center channel

By coincidence, the Klipsch approach to a fill-in center channel has led to a sub-thread on Audio Asylum. I seems my memory was all wrong, there is no subtraction of the two channels to produce a center channel, the two are simply added and reduced in level.

I think I mixed up the Klipsch center channel with a Dolby Pro-Logic decoder matrix...

Saturday, November 15, 2008

Chance find, vented frontloaded horn

I was looking for something completely different, but came across this article of the German loudspeaker DIY magazine Klang&Ton. It showcases four horndesigns, including some measurements and the construction plans. I was particularly interested by the page shown here, mainly because of the unusual and pleasing shape of the design. When I dug in deeper, I found that the basshorn is quite short, basically LaScala-like and the rest of the bass cabinet is a vented rear chamber. Very similar to what I showed earlier, in a very different form. Cool!

Scans of the full article are in this thread.

Saturday, November 8, 2008

Comprehensive list of Klipsch plans, vintage/heritage line

I see there are a lot of people looking for construction drawings of all the vintage Klipsch horn systems. I list plans for all of them here. Note that various versions of each model are in circulation, as are various derived designs. If you are serious about making an elaborate Klipsch design, you should really take some time to research the various available versions. There are differences (panel thickness for instance) and they might matter in your situation.

Original vintage Klipsch:

The Klipschorn is the big one, the design that PWK first released and that formed the Klipsch reputation. Other all-horn systems by PWK were conceived to offer Klipschorn technology in smaller or less placement-dependend packages (LaScala/Belle) or technological refinements (Jubilee). It is one of the most copied and home-built horns around. Obviously, with its long lifespan and many occasions of publication, there are bound to be many versions out there. They are all basically the same, although there seems to be a preference for older versions. The plans available online are often tied to a 1949 version of the Khorn. Due to the massive amount of plans and the apparently limited amount of differences, I list two: a full version and only the bass section.

Interestingly enough, the LaScala started out as a PA-speaker, supposedly used to fire speeches off a campaign-truck in an election. It turned out to work well inside the home as well and was taken into production by Klipsch. I list two versions. One is Klipsch authorized. It was originally in metric and published in Germany, there is also an update in inches available here. The other is a later reconstruction by a member of the Klipsch forum. Plans are here. This has been reconstructed from measurements on real life LaScala's. I think they measured dimensions that they could reach, and deduced the others.

Belle Klipsch
Basically, the Belle is a LaScala in different aspect ratios. It is the same height, less deep but wider. Horn/expansionwise, it should be more or less the same. There are some differences to be found, but these are fairly minimal and uncritical. The Belle was designed as a third, center speaker, to go between two Klipsch horns. At the time it was intended to fill a sonic gap, if the two Klipschorns were placed too far apart. There was a filternetwork to go with it, which summed/detracted the left and right channels and filtered out the center channel information out of it. I don't know where that filter schematic is, it would be nice to add it here. I think it was in the Dope from Hope series. I'll look it up for you. In any case, the plans I found are recently inferred from an actual specimen, by a Klisch forums member.


The Jubilee is either an update, or a replacement to the old familiar Klipschorn, it depends a bit on your perspective. PWK started the Khorn as a 2-way, but with increasing bandwidth of source material, stretching the midrange driver more into treble territory was unfeasible and the Khorn evolved into a 3-way loudspeaker. PWK was apparently unsatisfied with this and as his final act of speakerdevelopment designed the Jubilee, together with Roy Delgado. Under Related Material below, you can find the patent of the Jubilee, explaining the design considerations and strategy, I won't go into great detail here. Suffice to say it has equal or lower bass response and a significantly higher cutoff. The Jubilee is mostly found in DIY versions, since Klipsch is not selling a consumer edition. They will deliver the PA edition to private buyers. This is a fairly rough cabinet though and not livingroom friendly. There is an inferred set of plans online, which has been traced and reconstructed from the original patent.

Vented LaScala
I covered this area in an earlier post, which you can find here.

Related material:
  • Klipschorn paper, which is the patent paper in which the original Klipschorn was described.
  • Jubilee paper, featuring the design of the new cornerhorn, and a comparison to the old Klipschorn.
  • Dope from Hope, a periodical from the Klipsch company, in which PWK himself wrote about the things he thought were essential for high fidelity reproduction. Besides solid information from respected audio-engineer, it is also an amusing read. PWK was a unconventional thinker, and writer.

You will notice many of these files come from The maker of that website has his own Klipschorn-based system and loads and loads of horn-related literature online. Well worth checking out. Most of the other stuff comes off the Klipsch forums. I think Klipsch is great to acknowledge their rich history by keeping the heritage line alive. They are also wonderful for providing the vintage fans with this much information about their "old stuff".

MIA- no more Jubilee build report

I am doing maintenance and updating. I was checking some external links and read the link in this post:

"Deleted due to unethical people trying to use my work for profit!"
I'm not sure what happened. I certainly hope there isn't a misunderstanding involving myself. This blog is strictly non-profit and I hope the publication and use of these pictures wasn't the cause for taken the content down.

Again, it is a wonderful build report.

Thursday, August 21, 2008

"An Almost Round Horn"

Or, as the weblink is called in German, Ein fast rundes Horn (article in English, though). This is an oldie, it must have been pre-2000 when I read first read this. There is some really good practical stuff in here. It leads to a highly specific way of building a horn, that I never copied exactly nor directly. At the same time, every step and procedure gives lots of ideas for my own DIY-projects. I think you should read it and at the very least appreciate creative engineering. I bet some readers will get some ideas for their own projects.

The basic idea behind the article is that a round horn is good and a square horn is bad. But to make round horns requires a lot of effort and materials (moulds or lathes). Curved panel horns on the other hand are somewhat easier to make with more conventional home tools, like saws and the like. The further away your design is from square and the closer it gets to round, the better it is. The solution that this artical offers, is to use more than four curved panels.

Basically, you are making your own version of the classic petal horns of early grammophones. Of course, by choosing your own design parameters and materials/drivers, it will turn out rather differently in terms of looks and sound.

The reason I get back to this old article, is that I am building a set of petal horns myself, which I hope to showcase here occasionally over the next few months. Some aspects of my design and building processes are interesting as well. I will show and illustrate them here.

We are back and we are moving forward!

Monday, July 21, 2008


Just a note to explain the hiatus in posting. I have a new job which absorbs a lot of energy. But... I'll be back...

Tuesday, July 8, 2008

YouTube find: Tractrix Wood Horn For hobbyist And Technician

Speakerbuilding is about sound. As a consequence, I never really looked for speakerstuff on YouTube. Granted, there's some funny videos about hooking woofers up to the wall outlets, but seriously, why look at a speaker when you should really hear it. (The soundquality of YouTube gets in the way as well.)

Well this video shows why YouTube turns out to be really valuable for us: for showing practical techniques.

The creator of this video shows how he makes an adapter to mount a given driver to a given horn. Interesting to see him do it, and a very relaxed approach.

Monday, June 16, 2008

Extensive build report - Eyecandy

The Grand Klipsch Post is still being edited. In the mean time, we need something to get excited about, so I post this:

The URL is aptly chosen, in many ways. It is a build report of the Klipsch Jubilee, one of the horns that will be featured in the Grand Klipsch Post. It was sort of the anniversary version of the Klipschorn, hence the Jubilee name. The craftsmanship displayed does the design and legacy justice, which is also cause for jubilation. Finally, the builder/owners look very happy with the finished product, so I bet there's some jubilation in that house!
There are dozens, if not well over a hundred, photos there, that show the entire build process. He starts with raw ply and ends up with a furniture quality horn. Respect! You also get excellent views of the structure of the horn which, combined with the plans (upcoming in the Grand Klipsch Post!), allows better 3D visualisation of the horn.
Note that the Jubilee is considered an "easy build" compared to the traditional Khorn...

Saturday, May 31, 2008

Horns and the Google search algorythms

I'm working on a monster Klipsch post, compiling links to plans of all the fully hornloaded PWK designs. This will go from the original Klipschorn all the way to the Jubilee and should provide interesting references for anyone designing their own horn cabinets. In terms of creative design and cabinetry, PWK was in a class all by himself.

I thought compiling this list was going to be pretty easy. There's lots of stuff on Klipsch out there, the plans for all of these designs have been published in print and online and there's enough buzz to keep it around. So just type in the words "Klipsch", "horn" and "plan" and they should pop up, right?

Well, they didn't pop up so easily. What you mostly get is threads on the various speakerboards, discussing plans of Klipsch horns. So, more search terms. Try out "LaScala", "Belle", "Klipschorn", "Jubilee", "DIY" and whatever else you come up with. It doesn't really help...

What happens, is that Google ranks the search results, following a weighting system. Listing the actual words is important, of course. But also how many times the word is mentioned in the text. Also, how often the page is read. Perhaps how many pages refer to that page. In the end, the original design, website or post is completely lost in the forest of forum activity about the topic, simply because the forum activity is much more and highly conspicuous.

We've been generating so much talk and so little content, that it becomes increasingly harder to find the actual, relevant information. By this post, I am actually adding to the clutter... I decided to post this anyway, because it illustrates the need for a few online places that are about focus and content. The HornloudspeakerMagazine aims to be such a place. I can't produce expert technical literature about horns, but I can point you to some excellent stuff. It might save you a week of Google nightmares... How does Brainiac put it? "We do these experiments, so you don't have to"...

So, stay tuned for that monster Klipsch post, because I have very nearly found everything I am looking for.
(Image from the Klipsch Forums)

Monday, May 26, 2008

Preserving the Knowledge of the Ancients

I know that all of you technical minded horn-fans are looking for Harry F. Olson's book called Dynamical Analogies. This is one of the most, if not the most cited reference for in-depth understanding of the functioning of horns. As the title indicates, Olson illustrates analogies and describes the acoustic interactions of soundwaves with alternative principles, like electronics. My background in math and engineering is ...... limited (cough)..... so this book is over my head. Although I do browse in it from time to time and I understand more every time. Some day. In the meantime, long live Bruce Edgar for making horn design more accessible to me with his popular style.

Anyway, here's a link to an online library of technical books, mostly audio-oriented. You can find it at Technical Books Online. These books are decades old and their copyrights have not been renewed. The maintainer of this website (webrarian?) is therefore free to offer them online. The direct reason that makes it elligible for a post here, is that it provides Olson's book. However, there are many more interesting books at this site.

Among the very interesting things that I found, are Magnetic Recording - Wire and Tape by M. L. Quatermaine, a wonderful little book with lots of diagrams and illustrations. Anything you never knew you wanted to know about your tapedeck!

There are also a lot of audio textbooks, of varying level. I am an educator myself and am of course interested in both "vintage educational material" as well as in improving my knowledge of things audio. I can tell you that some of this vintage material is still excellent textbook material, if you can look through the outdated graphic work. Didactically, there isn't much wrong with them and I enjoy reading them.

Happy browsing!

Monday, April 28, 2008

Dynamics To The People - Bjørn Kolbrek's Private Website

A few posts below, I linked to the articles "Horn Theory: an Introduction" by Bjørn Kolbrek. I forgot to add a link to his private website. I have actually known about Kolbrek and his horns for years, he's had his system up online for years now. It has been fun to follow his developments and I was extremely jealous of the "Kolbrek Sub Horn". I didn't realise his engineering background, the papers published in AudioXpress took me sort of by surprise.

In any case, it is interesting to see what kind of stuff is built by someone who knows what is important and what isn't.

Friday, April 18, 2008

Hornresp 19.00

I passed announcing the release of versions 18.20 and 18.30, because I thought it was getting a little too much, announcing updates almost every other day. This is a fully new version, however, so I am glad to announce it.

I am even more glad that I had something to do with it. David McBean is open to suggestions for his software and many DIY-ers give them. I took the opportunity to ask for off-set driver mounting. This means mounting the driver not at the throat, but at some other location along the horn path. This alters response and can therefore be used to tune the horn in a specific way. Just one more tool in the toolbox. The trick itself, off-set driver mounting, is also known from transmissionlines and TQWTs.

Anyway, David refused initially, but suprised me by releasing version 19.00, with the off-set driver mounting. Thanks David!

Hornresp download site.

Chance Google Find: Horn/Dipole Hybrid

I was looking for Onkens, go figure... :)

Published on diyaudio, by CLS. The midhorn is an Oris 150 by BD-Design, in this case not used with fullrange drivers, but with a focal midrange driver. This system really struck me, because it's an interesting combination between a few things.

First of all, I am a fan of the Oris-style tractrix/fullrange approach to midrange. I have been sold since hearing various Oris systems at the BD-Design showroom and in private homes. A hornloaded fullrange driver gives an excellent overall combination of range, dynamics, resolution and easily achievable coherence. The compressiondriver loaded Oris horn takes it a step further, but the price reflects that as well. I don't have the budget for real Oris horns at the moment, but I have been able to get at least some of the magic with DIY horns, which is proof-of-concept to me. Clearly, the maker of the featured system took a different approach and uses separate midrange and treble drivers, which is fine too. In general, the directional nature of a tractrix horn reduces negative room interactions in a domestic environment (less reflections off side walls), which is useful.

Next is the dipole section. Dipoles are very hot for bass at the moment, partly because they excite roommodes less. The front and rear waves are out of phase, they meet at the edge of the baffle and cancel each other out. In a normal box speaker, the sound is radiated in all directions, but in an open baffle speaker the radiation towards the sides is much reduced. With less sound going into your room, there is less chance of room resonances and other room interactions. Dipoles are also much less efficient than basshorns or box speakers. Overall, people that use dipole bass seem to value the reduced room interaction more than efficiency. You can read more about dipoles at Linkwitz's site or, if you can read German, at dipol+. Also note that dipole is also used for midrange and treble applications and there are strong points to be made for that as well. Linkwitz is a particularly good source for that.

In any case, considering midrange horns are appreciated for their reduced room interactions, and dipole bass sections are appreciated for their reduced room interactions, it seems logical to combine the two. This full blown approach, with three 18" woofers per side, also seems to aim to "fix" the lower efficiency of the dipole section compared to the midrange and treble section. It's large (the television is 53", for reference), I wouldn't readily put it in my own living room, but I see the how and why behind the design.

Finally, it reminded me a lot of the Western Electric theater horns with dipole bass sections. Their obvious strong point was the elaborate and finely designed HUGE midrange horn. Their obvious weak point is the extreme time delay caused by the very long midrange horn. The added path of the soundwaves makes them arrive much later at the listener's ears than the soundwaves from the woofer. According to the Lansing Heritage website (also the source of the image), the delay issue was so serious, that the click sounds from tap dancing could be heard twice; once from the woofer and once from the midrange horn! The featured system is a nice iteration of the Western Electric style system. It features a midrange horn with a fairly low cutoff, mated with a dipole bass section, without the tremendous time delay.

Saturday, April 12, 2008

More wood/DIY multicell horns

I knew I had a nice link somewhere in my bookmarks...

This is a French effort, from the website, showing audio gear by Jerome and Thierry Prevost. I havn't had contact with them, but I assume they are brothers sharing a nice hobby. :)

They have several pages detailing this and other horn developments and show some of the design and construction steps. It's all in French so might be a problem for some, but the pictures alone are worth more than a million words.

(Note: although this horn consists of cells, due to its general lay-out and expansion style, it would probably be more accurately described as a radial horn. Examples of this style follow later.)

Thursday, April 10, 2008

CH Audio Design - beautiful craftmanship

I just came across the CH Audio Design website, through a link posted on Audiotreff. This company (or person?) offers spectacular wood reproductions of the Altec 1505B multicell horns. This style of hornbuilding, splitting the horn into smaller segments and pointing them in a radiating style, is intended to prevent beaming. These smaller segments are the multicells. In the usable pass-band, the wavefronts of the individual horns combine well and a smooth response and wide dispersion is achieved. At higher frequencies, each individual multicell exhibits beaming.

There is more than just pretty pictures there, including a set of drawings for an adjustable base assembly, allowing variable tilting. If, like me, you are used to adjust the position and angle of your midhorns by adding books to the stack underneath your driver (...), you will surely appreciate this feature. :) Also interesting to see is Dietmar of Germany's system. Clearly a Big Rig.

Tuesday, April 1, 2008


I am pleased to announce that this blog has had over 10,000 pageviews since it's start. It's a real joy when people read what you collect/write for them, so thanks for stopping by every now and then!

Sitemeter offers a lot more information than just pageviews. It also shows entry pages, referrals, what search words were typed in Google to get to this page and also, interestingly, how you *left* this site. I set out to make this page a place that could direct you to the information about horns you want to find, good quality stuff that you want to read. It seems that many of you do indeed follow the links and look at the stuff. I am happy to reach that goal.

Also, a lot of people look for stuff on JABO horns. I will endulge and string together some JABO stuff.

Otherwise, just thanks and I'll try to keep it up.

Sunday, March 30, 2008

Wow... Hornresp 18:10...

McBean is a fast and enthusiastic worker. As far as I've checked, the update entails a compression chamber option for tapped horns.

Hornresp download site.

Saturday, March 29, 2008

Kolbrek on horn theory, an introduction

The audioXpress magazine has a couple of articles out, an introduction to horn theory by Bjørn Kolbrek. This introduction has a more theoretical approach than the papers bij Bruce Edgar in Speakerbuilder magazine. You can download these files at:

Part 1
Part 2

Tuesday, March 25, 2008

Hornresp update: version 18.00

David has put more options in the tapped horn wizard. It is possible to shift driver position with a scroll bar and see the frequency response chart change in real-time. This makes it much easier and quicker to find the right driver position. A great update!

Find it here.

Monday, March 24, 2008

Schmacks Sub in Sketch Up

This is just a quick one with some pictures.

Before I made this horn, I made a Sketch Up model to see where all the panels went. When I started the model, I wasn't sure yet, but when I realised how few panels there are and that most are pretty easy to cut and position, I decided to go ahead. Here are two depictions of the interior, that make it easier to visualise the internals of this horn:

Next is what I believe is the standard, intended placement of this horn, in a corner.

Finally, this is the way I wanted to put it in my room. You can see it's put on its side. This makes no difference to the functioning of the horn, as the boundary loading is exactly the same. The footprint is a lot smaller though, so this positioning takes up less space.

The corner Schmackshorn, a subwoofer

A familiar classic backloaded horn, is the Schmackshorn. While I can't precisely trace back the maker of the original design, I do know that the most widely known versions are from the Klinger book of loudspeaker designs. I mentioned this book earlier in reference to the Dinohorn, anyone interested in European horn DIY will come across it a lot. I know of at least two other derivations, which take the original design elements a step further. One is the Isophon version, with lots of reflectors, the other, is the Side Vivace, an adaptation for Lowther and other fullrange drivers, which uses helmholzresonators to smooth response.

The Schmackshorn is famous for being a fairly large and uncompromised horn. Its size enables it to have a low and efficient bass response. This is something that many fullrange drivers need help with, so the Schmacks was often used with such drive units. Combinations by Philips/Norelco, Coral, Lowther and Fostex are known, probably many more. An added trait of these horns, of larger horns in general, is that their hornmouth/radiating surface is very large and therefore closer to the size of a natural low frequency soundwave. Most backloaded horns have fairly small mouths. While small-mouthed horns can sound good, large mouths generally tend to help a lot.

A fascinating combination of both (large mouth and lots of driver surface), is this version of the Schmackshorn. Click image for a higher resolution. This comes from an Italian website and there are more Schmacks-plans there.

It is a design for a 12 inch driver. It was also featured in the loudspeakerbook by Klinger. This is another backloaded horn, with a rather simplified but clearly Schmacks-style folding. As far as I know, this is a bottom-firing corner horn. The only illustration (drawing, not a photo) of an application I saw, was two of these firing in corners. I haven't found more details on placement. I think it is very likely that it is a corner horn, or is suitable for corner placement, based on length and mouthsize calculations.

The Schmackshorns are "old-style" horns, which means they are designed around a number of standard rules of classic horn theory (the type by Olson). These horns generally had a quarter wavelength of the lowest intended frequency, and a mouthsize appropriately reduced for room placement (1/8th for corner placement, 1/4th for wall placement, etc. etc.).

After measuring the internal length of this horn in a few different ways, I always end up with a hornlength of around 280-290 cm. The quarter wavelength of a 30 Hz, is 285 cm, so I have decided that his horn is very likely a 30 Hz horn. Reverse engineering the mouthsize is somewhat harder, as its bottom firing. A general rule of thumb I have seen for bottom firing horn mouths, is that the final mouth size is about two times the mouth coming out of the cabinet. However, I have also seen suggestions of 1.6x to 3x as large. Also, making the final hornmouth smaller is a trick to modify/repair the acoustic impedance of the horn, so relating the mouthsize to a cut-off frequency is tricky. I come up with estimates between 6,000 and 9,000 cm^2, of which 9,000 cm^2 would be expected with a 30 Hz flare rate (throat size is 400 cm^2). Pretty good approximation, if you ask me.

Simulation in Hornresp shows that the difference is rather insignificant, leading to only minor differences in the simulated response. These are most likely smaller than the accuracy of Hornresp, so from here on, I consider this to be a 30 Hz horn, with a mouth of roughly 9,000 cm^2. Considering I model this in a corner, and considering some designed-in extension of the horn using room boundaries, this is not unlikely at all.

Furthermore, we can see a cancellation dip around 100 Hz, which is where the directly radiated sound interferes with the horn sound. It is interesting to note the cabinet design has parallel surfaces between the floor and the (inside) top of the cabinet. The distance between them is about a quarter wavelength of 100 Hz. A possible occurring standing wave will attenuate the horn sound at 100 Hz and the cancellation dip may be greatly reduced by this. This is a feature also known from the Olson backloaded horn and a suspected factor of succes in the Fostex recommended enclosures. By either placing these standing waves at a single frequency or spread out over a larger area, response anomalies can be controlled acoustically. A very interesting feature of this design. I have no measurements of the horn, so I don't know if it works the way I see it.

Now, I used to have one and I liked it, but threw it out when I moved to a new home. I regret that now. It had a really nice low bass range. It was a bit messy in the crossover region to midrange horns (220 Hz), but then again I had no measurements and therefore the crossover was messy. I'd really like to build one or two again and do measurements, a good crossover, apply it in an appropriate range. It really deserves it.

(Note: I posted this a day or two, three ago, but because I started writing on this post earlier in March, it was posted way below. Apparently you give it a date and time of posting when you start the draft. I moved it back up, since it's the most recent message. )

Sunday, March 16, 2008

Lowther Voigt Museum

Here's a really nice link!

Paul Voigt was the developer of what we now know as the Lowther drive units. These are developed a bit further, but much of their design is as it was in the thirties. While there are other strategies for fullrange drivers with high efficiency (ie smaller or larger diameter, without whizzer cone, different materials, different suspension characteristics), the Lowther school is still highly respected and led to other drivers following a similar strategy. AER and Fostex come to kind, Feastrex as well.

Paul Voigt initially put these drivers in large frontloaded horns. There were large, ready made, furniture grade cabinets, but also a DIY kit to be built from plans, pictured here. Whether he designed the drivers to be placed in horns, or designed the horns to make the drivers work, I don't know, but the end result is the same. This type of drivers has a response curve and a suspension type that works best in a frontloaded horn. By this, I mean that there is more treble and a general decline in lower frequency response. The horn boosts the lower frequencies and restores balance. The horn also reduces distortion, damps resonances in the driver, and gives that horn flavour that counts (even if only psychologically). In principal, you can apply this to any low Qts driver with a tilted frequency response.

Modern examples of large horns for these drivers, are the Oris range of horns by BD-Design. I have used Lowthers in "official" backloaded horn designs and was quite happy with the results, but after hearing a full-tilt Oris system at the BD-Design audition room, I started making fronthorns for my Lowthers as well. The positive effect of front hornloading was strong, expect a more dynamic, relaxed and controlled sound.

Back to the Lowther Voigt Museum. Basic horn formulae haven't changed much since the days of Paul Voigt, the application of these rules has. Nevertheless, it is very interesting to see these old designs and meditate on the creative use of knowledge of the time. Even if you don't build a Home Constructor Horn, it is noteworthy that Voigt obviously saw an advantage to using a large frontloaded horn, as opposed to say a backloaded horn, or use a smaller fronthorn to go with the TQWT/resonant pipe. Apart from this, it's just cool to see some pieces of historical significane.

The website offers some history of the company and persons, it gives pictures and descriptions of products and. apparently, the museum also sells copies of brochures and plans.

Tuesday, March 11, 2008

Collaborative Tapped Horn Project

Posting here has been low, but there continues to be a constant flow of hits and views to this magazine. There are loads of people interested in hornloudspeakers online and they clearly want more stuff to read. This, I can provide, through a bulky link...

By now, a lot of horn enthusiasts will be familiar with the Tapped Horns of Tom Danley. In tapped horns, the driver is placed in such a way, that both front and rear are inside the hornpath and contributing to the final frequency response. is hosting a thread by a number of DIY-ers, who have been reverse and forward engineering the tapped horns. Tom Danley even pops round to offer advice and hints!

This entire thread is interesting reading material. With the aid of hornresp and some background knowledge, a functional tapped horns is easily designed and constructed (think folded TQWT and you're 95% there). Those who have tried it, are generally over the moon.

Here is the link, knock yourself out with some excellent, innovative, exciting and yet accessible reading material. I start on page 1, the thread has grown to 136 pages by the time I am posting this...