MP3 in the House

A few years ago, I converted all of our CDs to 320kbps MP3 files. I considered using a lossless codec instead of 320kpbs, but I read about a very interesting blind test where 256Kbps MP3 files could not be discerned from the original CDs. What made this study special was not the number of participants but the fact that they were sound engineers from famous music studios, symphonies, and hifi manufacturers. So I bumped up the sampling rate to 320Kbps, just to be sure since I didn't want to rip 1000 CDs twice. I also decided to use constant bit rate (CBR) instead of variable bit rate (VBR), because the greater compatibility of CBR was more important to me than saving disk space.

We have more laptops than people in my house, so I set them all up on the kitchen counter, and the ripping went pretty quickly. By the time I loaded the CD into the last one, the first one ejected because it was finished.

The next decision was the best way to playback the music. First I connected one of my old laptops to the stereo using the line out from the laptop to the line-in of the receiver. The music collection is over 80GB, so the old laptop didn't have enough disk space, so I tried to store all the files on my file server, and connect to the file server over the wireless network.

Unfortunately the wireless network was just too unreliable for long stretches of listening to music, and there was no easy way to install a wired network to the audio cabinet. Larger hard drives are pretty cheap though, so I upgraded the laptop for less than $100 and stored the entire collection locally. The sound was picking up obvious interference, so I added a PCMCIA soundcard with optical output to the laptop (Creative Sound Blaster Audigy 2 ZS Notebook sound card). This completely eliminated the interference problem that was caused by either the cheap DAC in the laptop or the interference picked up by the line-level signal on the way to the amplifier.

For portable music players, the 320Kbps is a bit much, so I downloaded Easy CD-DA Extractor from download.com to run as a batch to down sample the music to 160Kbps. I have to admit ignorance of the inner workings of the MP3 algorithm, but in most codecs downsampling by a factor of two produces a cleaner result than fractional downsampling.

Now that I am in a house with a wired network, I am using the Playstation 3 as the MP3 library interface instead of the laptop. The PS3 connects to the server, which uses Windows Media Player 11 music sharing to send the music on demand over the wired network, and the HDTV is the interface for selecting the music instead of the laptop on top of the audio system. The ease of use, the HDTV interface, the wireless controllers, and quality audio make for the perfect setup.

The next challenge was to get the audio to the speakers in the ceiling. The new house had five pairs of speakers in the ceilings on the first floor, with a Niles VCS100R volume control in each room. I decided I could avoid buying a new piece of audio gear since my Model 7700 7-channel Balanced Amplifier has 7 channels and I only use 5 channels for my surround system (Axiom 4 x M80, 1 x VP150 v2, 1 x EP500 v2) in the living room.

The speakers in the ceiling are 8 ohms, and the amp can easily drive 4 ohms (it is designed to work at 2 ohms for head room according to the engineers at Outlaw Audio). However, when you attach five 8 ohm speakers in parallel to a single channel, you are left with a 1.6 ohm load, which would kill the amp. The VCS100R volume controls have a switch to double (or more) the impedence, which makes the load 3.2 ohms - well within the capabilities of the amplifier.

If you are connecting ceiling speakers, the heavy gauge wire required for the long runs won't fit in an off the shelf solution like the Niles VCS HUB8. I used two six-speaker wall plates in a 4 gang j-box to connect the heavy gauge wire together in a parallel circuit (you could also use one larger unit like the Niles HTP-7.1 ). The binding posts can be be jumped together on the rear using stripped speaker wire, and all of the speakers can be connected to the binding posts on the front, along with the 2 pairs that connect to the 2 amp channels.

The ceiling speakers are configured as a second zone in the receiver ( Model 990 Preamp/Processor ), so they can either play the same thing as the living room, or they can play music while the sound system in the living room is used for watching a movie.

Now we've got MP3 in the house.