How to drive a passive subwoofer with a 7.1 receiver ?

You want to drive a passive subwoofer or amplify your Hi-Fi system with real Bi-amplification? Then this little trick will explain you how to do it with "Zone 2" option.

Most of 7.1 receivers have a Zone 2 option which enable them to work in 5.1 + 2.0 for another set of speakers located in another room (really ?)


We'll use that second embedded amplifier to power the bass !

I connected the LFE to DVD IN but any analog input should work.

My subwoofer uses two speakers so there is two ways to drive. You can easily solder a custom cable or buy one in your favourite online store :

Now we are ready to go ! Let's set up everything

I'm using another amp to drive my front speakers

Go in your receiver's menu :
For the main zone, make sure LFE is enabled and your speakers are set to small (setting your front speakers to large will automatically disable LFE when listening to music)

Switch on the "Zone 2" mode. Assign DVD IN (or the other input you plugged in) to Zone 2 and turn the volume up ( not too much ;-)

Here you go, you subwoofer is now powered by your receiver!

How to build a pre-out on Pioneer VSX-921

Yesterday I opened my brand new Pioneer VSX-921. The goal was to build a pre-out connector to connect a real amplifier : a Rotel RA-820A.

Rotel RA-820A taking care of the Front Channel over Pionner VSX-921

Let's look inside the beast :

• The green PCB is the Digital I/O board
• On the upper left corner, when can see the power supply.
• Of course the large radiator is covering the power amplifier board.
• The audio Signal processors and analog I/O are under the green PCB.

Let's find the pre-out signal !

We are looking for the pre-amp signal in order to extract it and feed a better amplifier. So we just have to find the wires between the DSP/Analog board and the amplifier...

Bingo ! Too bad we can't exactly see what's written ... But sure it's here !

Now let's find a convenient way to solder a bunch of RCA plugs... You will have to unscrew one support board and remove three plugs to access it ... no big deal!

Found it! A quick soldering and here we go, the left channel is available !

FYI : 

1 : Front Left

2 : Gnd

...

9 : Front Right

10 : Gnd

The two main channels are extracted, let's pu everything back in place and enjoy the cristal clear sound out of a real amplifier !

Here we go !




Next post will be a small but usefull tip how to use Pioneer's VSX-921 integrated amplifier to drive a passive subwoofer (or bi-amp).

Review : Bigfoot Networks Killer Wireless-N 1102

Few days ago, I've decided to buy a new WLAN controller for my laptop because the embedded one does not support 5GHz Wi-Fi aka 802.11an

After having read a quick review on Anandtech , I decided to replace my Intel Centrino Wireless N 1030 adapter by the wall breaking Bigfoot Networks Killer Wireless-N 1102.

It cost me around 30€

Here is the mini PCI-E module with the two antenna connectors.

Fits perfectly inside my DELL Vostro 3350 next to the Crucial C300 

Driver Installation
I downloaded the driver (40MB) for Windows 7 x64 on the official website and installed it as my Intel WLAN Module was still in place.

When I installed the Killer Wireless-N 1102, it was automaticcaly recognized by Windows and ready to fire :)


Signal Quality
This is before, with Intel Centrino Wireless N 1030

17 access points !

At the same place with the Bigfoot Networks Killer Wireless-N 1102

44 access points !

Good news, I can reach a lot of new networks I never saw before.

Channels 
However, there is a weird thing, my home network use the channel 13 and I can't see it on the graph... This is probably due to the regional Wi-Fi  channel configuration (11 channels for USA, 13 for the rest of the world)...

I tried to find this parameters in the Windows settings but I was unsuccessful. Anyway, after few seconds, my laptop connects to my home network on the 13rd channel... I need to go deeper

Still writing this article

Reinstall Grub after Windows 7 erased it from the MBR

You just reinstalled Windows on your dual boot computer and it removed Grub, now you can't access to your Linux (Ubuntu in my case)... Here is how to fix that :

Boot on a Linux live CD/DVD or USB Stick

Let's assume my harddisk will be called /dev/sda

Make yourself root :
sudo -s


List your patition to identify the one which contains your Linux system
fdisk -l /dev/sda


Create a folder and mount your Linux on it
mkdir /mnt/mylinux
mount /dev/sda1 /mnt/mylinux (where 1 is the partition number of your linux system I identified before)

Check if you recognize your system :
ls -l /mnt/mylinux

Now we have to bind sys, dev and proc
mount -o bind /dev /mnt/mylinux/dev
mount -o bind /sys /mnt/mylinux/sys
mount -o bind /proc /mnt/mylinux/proc

Chroot to your system by typing
chroot /mnt/mylinux /bin/sh


Reinstall Grub properly
grub-mkconfig > /boot/grub/grub.cfg (menu.lst is you are using old Grub)
grub-install /dev/sda


Done !


Unmount everything and reboot :)
exit
cd /
umount /mnt/mylinux/dev
umount /mnt/mylinux/sys
umount /mnt/mylinux/proc
umount /mnt/mylinux/
sync
reboot

Use ICC Color Profile on Windows 7

My Dell Vostro 3350 screen is very bad calibrated. Everything looks ugly and cold by default!

Unfortunately I don't have any Color probe to create a custom ICC Color Profile but I found one on this excellent website : http://www.notebookcheck.net/Review-Dell-Vostro-3350-Subnotebook.54680.0.html

Anyway, the point is, I got my ICC color profile and I want to use it on Windows 7 but when I install it, it doesn't want to apply !

Here is how I got it work :

Go to the color profile panel

In the advanced tab, click on change system defaults.

The same windows appear, but as Administrator. Again, go to the advanced tab and check if the "Use Windows Display Calibration" is thicked.

Now go back to the Devices tab and import your Profile.
You will also import another profile, pick any of the default ones.
Select it and Set it as Default profile

Then select the profile you really want to apply and set it as default. At this point, the profile should apply in real time. If not, try calibrating your screen with Windows tool and re do all these steps.

Potentials issues :
If you are using Intel HD Graphics like me, the igfxpers.exe process might reset the profile to a bad value each time your screen is blinking or the UAC is prompted.

Is this case, juste disable it from the boot with msconfig.

Fix Windows 7 boot and remove Grub

Just removed my Ubuntu Linux and decided to restore Windows 7 boot manager

Boot on Windows 7 USB or DVD


First try :
Bootsect /nt60 C:


Second try :
bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd
bootrec /scanos

Third try :
bcdboot c:\windows


Should work :)