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:

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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high end low end 
Friday, July 10, 2009, 16:12
Posted by Anders
So it was time to finalize the project started on one year ago, my new subs.

These fairly unremarkable little boxes are the result of the top 3 audiophile brainiacs in the tapped horn category in sweden today, and my self.

They each house one B&C 15TBX100-8 2kW 15" woofer loaded on a tapped horn device, they should be capable of producing some 130dB och output over the 40-250Hz range.

Considering their size 500x680x550 mm (BxHxD) this output and range capacity is certainly impressive.

They do indeed sound bigger then they are, by a mile or so.

Another nice feature of the tapped horn design is that the cone excursion is very modest in comparison to the output power, the sensitivity for one of these boxes if put on an open field with no support from nearby walls would still amount to some 100dB/W/m.

The above image shows a quick test we did to check how the soundpressure desipates over distance, at some 8m away you could easily feel the impact in the chest, at approx 20W of input power, that's pretty sensitive, and considering that each box can take up to approx 2kW each the output capacity of these subs are quite impressive.

Many thanks to Johannes and petter for helping me along.
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Home Theatre PC Project 
Sunday, February 1, 2009, 15:45
Posted by Administrator

After using the XBOX I found in the garbage room of my apartment for 3 years it was time to graduate. The XBOX did a very good job as a media player, however the lack of CPU power made it impossible to play any HD material. With the latest development of the XBMC (XBox Media Center) and the portable code enabling it to run on several platforms there were more options to choose from. The choice was a Linux based platform using the Ubuntu 8.04 distribution. As size and power efficiency (to keep the temperature low) the choice of hardware was a motherboard with built in Nvidia graphics and a low power Intel CPU capable of decoding 1080p material. Please find full Hardware listing below:

Montherboard ASUS P5N7A-VM
- This was chosen for it's size, built in Nvidia 9300 graphics and HDMI output.
CPU Intel E8400
- This is low power CPU fast enough to decode any material up to 1080p quality.
HTPC case Antec NSK1480
- Small case which had a big enough power supply (350W) and speed controllable fans.
CPU Fan Scythe Shuriken
- Low profile CPU cooler with big quiet fan
Hard disk Samsung/Keian SSD 32Gb
- Cheap and fast SSD hard disk
Memory 4Gb DDR2 800
Remote control and display iMON IR/VFD PAD

Total cost was less then 500 USD for all the above.

The hardware installation was quite straight forward and all things basically worked as planned. The iMON have a good feature that enables it to turn on the PC via an IR remote control (it's connected to the HW power switch on the motherboard). Also the iMON's display is supported through LCDproc in XBMC and will display information while playing media.
To control XBMC I'm using the wireless XBOX controller I had before (a Logic 3 Freebird controller bought at Julia Sweden for 199SEK). A simple soldering exercise and the interface was changed to a USB connector. If you don't already have a controller I would recommend getting an XBOX360 controller and a USB receiver as then there's a quite straight forward installation and you do not need to become a C++ programmer again (see below).

The software installation was also quite simple. Basic installation of Ubuntu 8.04 (I didn't go for the 8.10 version as there were a number of problems reported using XBMC with 8.10). After installing the OS I manually installed NVidia drivers version 177.82 and ALSA 1.0.18 in order to get HDMI and sound over HDMI to work correctly (sound over HDMI also require a BIOS setting). After this I setup the software sources in in order to get apt-get to find XBMC and install the latest stable version. There are a lot of very good information including step by step instruction on how to setup XBMC on the hardware used available on the forums on xbmc.org and ubuntuforums.org. Also do use Google and search for "P5N7A-VM XBMC" for a lot of good information. In order to get support for the iMON I had to install LIRC and LCDproc. Both SW fully support the iMON, however there were a little hands on needed.

The XBOX wireless controller I had I finally got working using the xboxdrv software and a few hours C++ programming. If you use a XBOX360 controller it should however be a rather straight forward exercise.

In addition to the above I'm running CygWinX on my PC and use gdm/xdmcp to get a graphical environment to access and administrate the media box.

The whole setup probably in total took ~30 hours, however then I was playing around ans testing quite a lot. The only problem was with the standby power used by the iMON. For some reason the motherboard though the voltage was off at power on when the iMON was connected to the standby power. This which caused the PC to refuse to start. The workaround was to connect the iMON power after the standby power had come on. I'll make a small delay circuit do fix this later. Also to ensure maximum cooling of the graphic chip which can get quite hot a simple paper barrier in the case directed the airflow better and reduced the temperature with about 5 degrees.
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