2006 Nov 15 - Wed

Sennheiser HD 600

A little while I was involved in a battle of stereos. I moved into a new apartment, one with kinda thin walls. I was without a music center at the time. My neighbor would play his TV/Stereo/Whatever and I'd hear the bass and side affects. I should have done the right thing and talked to him at that moment. But naah. I decided to play along. I picked up a 6 speaker Logitech system. My neighbor is an early to bed, early to rise sort of guy. But he would go to bed with his system on and let it play through the night. Aargh. I started coming home late at night and turning my system up. Half way through the night, I'd turn my off. He must have turned his down in the meantime as well. We kinda reached a happy medium. Then one day he turned his on at 6 in the morning. That got me to the point of getting on speaking terms with the guy.

So we reached a compromise. Naturally. He'd keep his down and I'll keep mine down.

However, keeping my music down just doesn't give me the quality and depth I'd like to see, or rather, hear. So a search for a good set of headphones ensued. I ultimatedly landed on HeadRoom's web site. They do high fidelity headphones. They bring everything together in one place. And talk about their products. No holds barred.

I ended up choosing the Sennheiser HD 600 series. I don't own a $2500 CD player, but I'll play high quality MP3's. From a audioholics perspective, I can't really say by how much they beat the pants off anything else in the audio sphere, but I will attest to a few things. But, yes, they do deliver great sound. One obvious physical characteristic is their open air concept. As such, they aren't good for completely isolating you from someone close to you. But they keep you quiet from someone in the next room. But that same characteristic redeems itself in another manner. They let your ears breath. They also let in some ambient sound just to balance things out.

The things are darn light as well. Couple that fact with the design of their open air concept, I can go for two, four, and sometimes six hour extended listening tours while working through simulations or software development projects.

Just thinking about their sound quality again. I'm wearing them as I write this. It is hard to get the true heart rending bass out of them I can get from my Logitech surrounders, but the headphones are still respectable in that regards. The midrange and highs are indeed superb.

To go along with them, I splurged on the 15' Cardas Replacement Cable. I can walk around my bedroom, sit at my desk, or recline in bed with them watching a movie.

I'll go into more details in another entry, but I also picked up the HeadRoom Total BitHead amplifier to drive the headphones.

All in all, I'm really happy with this setup. The only change would be to try out the HD 650 headphones and see if they are as good as they say they are.

[/Personal/Technology/AudioPhonics] permanent link

Backups With Mondo and LVM

Mondo Rescue is an excellent backup for Linux based boxes. With Debian, it is a one line install:

apt-get install mondo

As the existing partitions on the machine I needed to backup did not have enough space for the backup archive, I used LVM to create another partition out of spare drive space, created a jounalled ext3 filesystem, mounted in a directory I created for Mondo backups, and then started the archive program.

mkdir /var/backups/mondo/src
mkdir /var/backups/mondo/dst

lvcreate --size 20G --name lvBackup vg01
mke2fs -v -j /dev/vg01/lvBackup
mount /dev/mapper/vg01-lvBackup /var/backups/mondo/dst
mondoarchive

As part of the backup process, an image of /root/images/mindi/mondorescue.iso should be made to a CD. This will be used in the initial part of the restore process.

One more trick having to do with the LVM (Logical File Manager) has to do with snapshots. Since databases are typically being updated during the backup, the backup process will have obtained files in an inconsistent state. Use LVM to make a snapshot, use Mondo to backup the snapshot, and then use LVM to delete the snapshot.

lvcreate --size 500M --name lvBackupSource --snapshot /dev/vg01/lvVar
mount /dev/mapper/vg01-lvBackupSource /var/backups/mondo/src
mondoarchive
umount /var/backups/mondo/src
lvremove /dev/vg01/lvBackupSource

For the size parameter in the lvcreate command, use a size that will readily accomodate any changes made to the primary partition during the backup phase.

[/OpenSource] permanent link

Kernel Upgrades

I recently upgraded to Debian 2.6.17-2-686. A bunch of packages were held back. A few that subsequently need to be installed manually include:

• apt-get install lvm2
• apt-get install ntp

Without the upgraded userspace lvm2, the system will hang when trying to lvremove a snapshot. The system will need to be restarted to bring things back to life.

For NTP, I see they have changed the configuration file from using multiple instances of pool.ntp.org to assigning specific numbers, such as 0.debian.pool.ntp.org, in order to guarantee unique addresses from dns.

[/OpenSource/Debian] permanent link