A smaller sub proposal 
Saturday, February 20, 2010, 13:00
Posted by Anders
Another loudspeaker project, this time a much smaller 6.5" based version, but still it relies on the same tapped horn principles as the larger 15" version posted earlier in this blog.

On a side note I'm happy to announce that the 15" bigger brother design was built in Australia, Brazil, France, 2x USA (NYC and other) Macedonia and Sweden, and perhaps (probably) even more places that i do not know about yet.

Now it's time for a more domestic friendly version on the same theme, hopefully this, the baby version, will make for a small and easy weekend DIY project for those of you seeking to build a small sub for the computer or home theater system without upsetting the balance and harmony of the household.

This design has not been built to date, but the results of the design phase seems good enough to post for others to take part of.

Here's what it looks like as a 3D CAD representation :

(click the images to enlarge them)



Please note that the size of this sub is only 47x44x20.4 cm, yet it holds a 2,4 meter long horn path inside.

This is achieved by using 12mm thick plywood, and cleaver tweaking of the inner layout, the small surfaces also allows for a design entirely without inner brace panels.

Front view :


Section A-A from front view :


And then we have the Hornresp simulation input data :


The driver is the 6,5" Audes 40W65-8 that seemed to to the best job in the simulation of this very compact design, but there might be others out there that work just as well (as we found out with the 15" bigger brother).

The simulated SPL/frequency graphs below are made with several different placements in a room in mind, the input level in the simulations are 2.83 Volts or roughly 1W.

When placed in a corner :


When placed by a wall :


When placed in the middle of a room :


The intended range of this sub is 40-110 Hz but as we have seen before, the lower end range may extend further then that of the simulation by approx. 10Hz, this has been the case in many builds before, so with a little luck this small sub may reach down to 30Hz in room response.

The prefered driver for this design is the above simulated Audes 40W68 (previously known as 40W65-8), but I have looked at some other drivers that might work with this design as well.

The Seas H1224 L18RNX/P (corner):


The Seas H1215 CA18RNX (corner) :


The Peerless HDS PPB 830874 (corner) :


The Silver Flute W17RC38-08 (corner) :


18sound 6ND430 (along a wall) :


Beyma 6P200Nd (along a wall) :


If you want to build it please keep in mind that the mounting of the driver may pose a challenge but there are several ways to cope with this, either pre-mount it, or drill four holes on the cone facing outer piece large enough to fit the shaft of a screw driver, then mount the driver using nuts held in place by hand though the horn mouth, you'll figure it out.

Good luck with the build, please let me know what you think.

Br // Anders Martinsson
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Guildford - London 
Monday, November 23, 2009, 20:28
Posted by Anders
Last weekend we payed a visit to Maria's sister Ulirika and her family in Guildford, Robert, Lilly and Liv.

Guildford is a village of some 120.000 inhabitants, I use the word village due to the nice small town feel of the town's center.



It was very nice to take part of the lighting up of the christmas decorations, complete with fireworks and speach by the mayor.

We also checked out the small village of Shere (true village this time) just outside Guildford, very nice indeed I can recommend a visit, if so be sure to check out the White horse Pub from 1425, it's like walking in to a harry potter movie.

London was also on the tour, where we took a nice walk from oxford street via soho to picadilly circus, not far but very nice.

When passing D'arlby street we took a look at the BM soho record store where i picked up some of the following records:



Counting from the top left we have :

Sub focus, Nookie, Blu Mar Ten, Seba & Paradox, chronicles of the deep (compilation), Dat:music.

These where brought at BM Soho.

The rest are more mainstream and was found at HMV on oxford street, taking over from above we have :

Future sound of London, Boards of Canada (x2), and pendulum (x2).

A nice trip it was, and the BM soho shop was an musical oasis, manned by specialists in my type of music, helpful and fun to deal with, especially Rachel (the blond one :).

I'm still listening to the music, but sofar the nr6 track of the chronicles album CD1 Kantyze - Good riddance is my favourite, along with the entire Blu Mar Ten album - Natural history.

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high end mid/high end 
Friday, August 14, 2009, 21:31
Posted by Anders
Since the low end was updated it seemed only fair to take care of the rest of the speakers as well, i.e the mid and high frequencies.

And why not go all out hornloaded in the process you ask, well i concur, why not.

So let's borrow the mid horn device from the turbosound TMS range and pair it up with the 2386 40X20 deg 2" dispersion high range horn from JBL, and what do you get ?



The drivers are B&C (as allways), in this case it's the familiar 10MD26 / DE75P combination found in my (previous?) top system.

The result was another one of those "laughing-out-loud-I-can't-believe-it" moments, and that was only the quick & dirty test result, now all i need is another channel...



Looking at the how the two horn sections of each top speaker stack up it is easy to see why i went for the larger JBL horn, the dispersion angles are nearly identical, at least to the eye.



They sure knew what they where doing those guys at turbosound, the sound quality at the '95 Pink Floyd Pulse concert stands testament to that, now i have the same stuff at home, although be it in a much, much smaller scale.



Now it's time to take measurements, analyze, and program the DBX driverack unit accordingly, my guess is that this will turn out very well indeed.

Quick messurements shows that the sensitivity should be in the 108dB/W/m range, the response should be within 4dB from 200Hz to 16kHz, and the sound is simply amazing.

Not bad at all...
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high end low end - the field trails 
Sunday, July 26, 2009, 12:31
Posted by Anders
After some two weeks of so and so weather we finaly got some time in the sun, an entire afternoon no less, so what could be a better use of this opportunity then to stage an outdoor listening session.



This is the first time i use the new subs as they where meant to be used, in a free "field" environment, and it was mediately apparent that this is the way they preform the best.



I used them between 25-200Hz, wich sounded very nice indeed, and when listening to them they did not seem to have any of the peaks and dips that the simulations showed (below).

The RTA messurements for the two subs at approx 4m distanace showed a response between 40 and 300Hz with no explicit variations but 40-150Hz is the recomended as usable range.



Dreadzone, Yello, Leftfield, Covenant and Pink Floyd amongst others made up the proving ground, and the new system passed with flying colors.

These new subs has brought the entire system to a new level, rich, effortless, powerful and hi-fi like sound stage on a grand scale, and even at lower levels like in this case they are still massive enough for one to feel it in the ground and chest area.
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high end low end - diy notes 
Tuesday, July 21, 2009, 11:04
Posted by Anders
If you would like to build the subs shown below in the "hig end low end" entry then these simulations and drawings will be of help.

Using the hornresp analysis and simulation software provided for free by David J McBean i finaly arrived at a good enough result, shown below.

Some of it's in swedish, but the graphs and dimensions (mm) are of course international.





this is the link to download hornresp:
http://mywebsite.bigpond.com/dmcbean/

These sumilations are based on some very basic 2D AutoCad drawings, shown here :










Just print them out and get to it, or simply hand them over to your local expert along with the money, either way i think you will be happily supprised at the result once loaded with the correct drivers, i certainly was :)


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