New top speaker system 
Sunday, July 18, 2010, 18:40
Posted by Anders
Following my 15 Tapped horn build (aka. the andershorn as named by William Cowan) some time ago I thought it might be time to finally put together a top speaker system to match them.

My favorite professional speaker manufacturer Turbosound once upon a time took the world by storm with their TMS range, amongst these there was the TMS-2 fullrange top speakers, these where fully hornloaded and carried a 15, 10 and one 1 driver.

These boxes and the technology they contain can still today (some 20 Years on) still hold their own against the current industry standard, and if equipped with modern drivers they might even come out on top, back them they specified 108dB/W/m halfspace with +-4dB in the 80-18kHz range, so you can imagine what might happen if they are loaded with modern drivers...

The heart of the TMS range was the 10 turbomid device, a 10 horn capable of spanning the range from 250-4kHz, covering the entire vocal range in one horn, giving a nice presence and extreme transient capabilities to the reproduced sound, simply put, a dream.

And as it happens, this particular device has now fond it's way into my new top speakers :)

It may be an old item, but so is physics, and that has not changed much in the past 20 years at this level.

Why build a box if there is no need for it ?

There is something to be said about DIY chaos, it usually looks rather funny :

the first frame is finished :

finally the first assembly tryout :

meanwhile in the batcave...

Slowly they take shape...

And while thee glue sets...

Right now only color, finishing touches and wiring remains :

That's it for now, the remaining touch up's and system tests will take place some 400km east of this location.

More pictures will follow, describing the final steps.

Br // martinsson

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Fostex FX120 DIY proposal 
Wednesday, June 30, 2010, 14:30
Posted by Anders
Following my small tapped horn sub build it is now time for a set of small (again) satellite speakers to complement them, making it a nice compact DIY sub/sat system with a visually pleasing properties as well as high sonic performance.

Intended for use in the above 150Hz range (approx.) these speakers will not be intrusive, and looking at the sensitivity one sub per pair of satellite speakers should be a good match.

(click images for larger view)

driver details - ... ries.shtml

My Fostex FX120 fullrange drivers (se link above) intended for this build has been staring at me for quite a while now, so I thought it may be time to give them a home, at least design-wise.

For this purpose I brushed off an old favorite design of mine, a thin wallmounted speaker design with nice stainless steel details, not entirely uninspired by Bang&Olufsen.

At no more then 64mm deep and containing only 3.6 dm3 (liters) of internal volume it may not seem as good idea for speaker, but instead of regarding the room in which they operate as a acoustical necessary evil it makes use of it to increase it's low range output, a sort of half-space horn loading one might say, and as an added bonus it also does free up floorspace.

The images below makes up the drawings for these speakers, bare in mind that it has not undergone serious simulations yet, this is so far only a "gut feeling" design proposal.


Sideview (including sections):

Topview (including section):

Connector details (view from below):

Font cover:

Stainless parts:

And finally some basic renderings courtesy of desault systems :

That's all for now, more will follow.
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Saturday, June 26, 2010, 15:35
Posted by Anders
Midsummer is upon us, and what better opportunity is there to give the new members of my DIY family a proper outdoor test in a true 2PI (half space) environment.

Seeing as the neighbors was away, and it being a day worth celebrating, the acceptance for noise pollution would be slightly higher then usual.

There is no chance, i remember thinking, that these minute 6,5" loaded tapped horns could offer up any kind of solid low end under these conditions, at best it will be noticeable, but beyond that probably nothing.

Outdoor "free field" environments are particularly demanding on the low end, and the lower midrange, it all has to do with the directivity of the frequencies reproduced, the higher the directivity is, the greater the free field efficiency will be, it will no longer rely on walls for support, as is the case indoors.

As it turned out I actually ended up lowering them down to a mere +6dB over the satellites to get a good balance going, when crossed over at 200Hz they gave the small system a warm, full bodied sound with a good low end thumph with no hint of being out of it's element.

It goes without saying that the SPL's was modest, yet still well enough for most garden events, easily overpowering the occasional traffic noise leaving you to hear only the music.

I have no good explanation for how this works, but it seems that the TH principle does have something going for it directivity wise, what and how exactly i can not say.

I'm very pleased with the results.
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DIY GBG 2010 
Sunday, June 13, 2010, 13:26
Posted by Anders 's yearly do-it-yourself audio event took place in gothenburg this weekend, this time in Chalmers facilities in Johanneberg.

The lineup was somewhat thiner the previous years, but there was some really nice contributions, and there was a lot of curious visitors which is always nice.

Here's an example of mixing old and new technologies in a nice but potentially harmful way (hence the sign) :

This integrated ipod tube amplifier (above) was used with these small fullrange speakers that sounded alot bigger then they would have you belive :

Another example shows outstanding craftsmanship, unique styling and striking sound, this is DIY at it's finest :

Others put less focus on exclusive materials in favour of the engineering solutions, the results sounded a lot better then the pictures may lead you to think :

We also had some testing equipment on hand for those wanting to give their homemade electronics a tuneup :

My own contribution :

The biggest highlight of these meetings is the chance to see all my friends in this community, some of which i only meet once a year.
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The small TH race 
Sunday, April 11, 2010, 17:59
Posted by Anders
Today I got a visit from my friends in the audio-nerd community, Johannes and Joakim and they had each brought along one of their own design solutions in the small tapped horn segment.

Each one of these have different priorities and preferences as it comes to the bass they produce.

The two larger ones are of the constant area or tapped "pipe" family, that is to say they do not expand area-wise along the length of the path.

The middle sized of these had the most low end thump, but came up a bit short in the attack area, this makes it perhaps more suited as a good movie sub rather then for reproducing hard hitting rock'n'roll.

This was a deliberate move made by the designer Johannes, the 8" Tangband driver used in this sub is difficult (to say the least) to even get working in a TH, the choice of driver was not his but he made it work fine anyway.

The largest model was put together and specified by Joakim, the design however is Johannes, this one can best be described as a nice compromise between depth and attack, equipped with a 6,5" driver from seas it reaches down to 30Hz with ease and can certainly impress when it comes to SPL and thump.

The last and smallest was my own, which was the most rock'n'roll of them all, but lacking in the depth area compared to the others, it integrated more easily with the top speakers and offered the most upper end punch.

The small size made it sound lighter then the others, and as we later found out it weighs only half of the next one up, 10Kg's.

They all managed to put out amazing SPL for their size and drivers, mine topped at 119dB at the mouth, and the others was right around there as well, it translates roughly to about 110dB at a distance of one meter, and remeber, we are talking about 6,5" drivers here.

This is nothing short of impressive and comparable to much larger drivers if using conventional surface mounted designs.

All in all it was a happy and not to serious (at all) learning experience for all involved.

More about the "race" (pictures, measurements etc.) can be found here (swedish hififorum thread) :

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