Questions about capacity on 30g

You may be encoding your songs at a higher bitrate than normal, e.g. instead of 128 kbps, you use 192 or 256 kbps encoding. It also depends on the codec you use; AAC is generally a bit smaller than MP3, in my experience.

When a hard drive is advertised as 30GB, that is the raw space, before it is formatted. The ACTUAL space differs greatly.
Example: A retail 200 GB hard drive is approximately 190 GB, and a 512 MB flash drive is approximately 498 MB.

27.8GB is correct for an empty iPod. The difference is due to the way hard drive manufacturers measure hard disk capacity. (Binary vs. Decimal) You can read more about that here:
http://docs.info.apple.com/article.html?artnum=60955

How are you encoding your songs? 350 songs taking up 5.8GB is a lot which leads me to believe you are using some sort of lossless encoding scheme such as WAV, AIFF or Apple lossless.

You can check your encoding scheme in your iTunes / Importing preferences. ( Preferences > Advanced > Importing > Import Using: )

First off the difference between 27.8 and 30g is this read here:

http://docs.info.apple.com/article.html?artnum=60955

Also if the IPOD is in disk mode you can set the amount of space that is reserved for this use.
Under "Edit" and "preferences","Advanced" then "Import", what encoder are you using to import your CDs with? If it is set to the WAV Encoder this is the largest file size and should be avoided unless you are trying to keep the original quality as on the CD.

Here is some guidelines on which encoder to use when importing:

Encoder Formats On the IPOD

AAC (Advanced Audio Coding)
An up-and-coming compression format for digital audio. In terms of sound quality and data efficiency, AAC solidly beats the still-popular MP3 format — not surprising, since AAC is a newer, more advanced form of compression. According to some listening tests, AAC files encoded at lower bitrates (like 96 Kbps) sound as good or better than MP3s encoded at higher bitrates (like 128 Kbps) despite their notably smaller size.

AIFF (Audio Interchange File Format)
An audio format for Macintosh operating systems commonly used for storing uncompressed, CD-quality sound (similar to WAV files for Windows-based PCs).

Apple Lossless
Apple Lossless Encoding (also known as Apple Lossless, Apple Lossless Audio Codec or ALE) is an audio codec developed by Apple Computer that provides full, uncompressed CD-quality audio in about half the space of the original file.


MP3 (MPEG1, Audio Layer 3)
The most popular codec for storing and transferring music. Though it employs a "lossy" compression system which removes frequencies judged to be essentially inaudible, MP3 still manages to deliver near-CD sound quality in a file that's only about a tenth or twelfth the size of a corresponding uncompressed WAV file. When creating an MP3 file, varying amounts of compression can be selected, depending on the desired file size and sound quality.

WAV
A standard audio format for Windows operating systems, often used for storing high-quality, uncompressed sound. WAV files can contain CD-quality (44.1 KHz/16-bit) audio signals. However, CD-quality WAV files require relatively large amounts of memory — roughly 10 MB per minute of music.

First off the difference between 27.8 and 30 g is that space is partioned off for the IPOD software as well as other files.

Actually, Barbara... that's not correct. There's no partitioning at all on the iPod hard drive.
The difference is due to the difference between measurements of a gigabyte. A decimal gigabyte is considered 1000 Megabytes, while a binary gigabyte is 1024 Megabytes. Hard drive manufacturers and computer manufacturers are always at odds in the way they measure capacity.
http://docs.info.apple.com/article.html?artnum=60955

First, make sure that your files in .mp3 format (each song should be between 2 to 5 mb) not in .aiff format (each song should be between 20 to 50 mb).

1- In iTunes-->Preference-->Advanced-->import tap-->choose mps
2- Select the files in your playlist-->Advance menu--> convert selection to mp3
3- Delete the .aiff files
4- Sync to iPod
5- Enjoy it.

PS: My 60 GB iPod is only 55GB actul capacity and this is normal (System).

I corrected my post Rich, used an old answer that was not corrected.

When a hard drive is advertised as 30GB, that is the raw space, before it is formatted.

No, that's not correct. Formatting takes up a very very small amount of space. That's not the reason for the "large" difference.
Please read my posts below for a more accurate desciption of the capacity discrepancy.

The Geek Answer:

Understanding Advertised vs. Actual Drive Storage Capacities

Introduction

At some point in time, most users have come across a situation where a drive or disk being used run out of space even though there is thought to be plenty of space. A lot of times, this is the rude awakening for the consumer that the device they are attempting to store data on is not as large as it was advertised.

Bits, Bytes and Prefixes.

All computer data is stored in a binary format as either a one or zero. Eight of these bits together for the most commonly referred to item in computing, the byte. The various amounts of storage capacity are referred by a prefix to represent a specific amount, similar to the metric prefixes. Since all computers are based on binary math, these prefixes represent base 2 amounts. Each level is an increment of 2 to the 10th power or 1,024. The common prefixes are as follows:
• Kilobyte (KB) = 1,024 Bytes
• MegaByte (MB) = 1,024 Kilobytes or 1,048,576 Bytes
• Gigabyte (GB) = 1,024 Megabytes or 1,073,741,824 Bytes
• Terabyte (TB) = 1,024 Gigabytes or 1,099,511,627,776 Bytes
This is very important information because when a computer operating system or program reports the available space on a drive, it is going to report the overall total of available bytes or reference them by one of the prefixes. So, an OS reporting a total space of 70.4 GB actually has around 75,591,424,409 Bytes of storage space.

Advertised vs. Actual
Since consumers don't think in base 2 mathematics, manufacturers decided to rate most drive capacities based on the standard base 10 numbers we are all familiar with. Therefore, one Megabyte equals one million bytes while one Gigabyte equals one billion bytes. This isn't too much of a problem with fairly small numbers such as a Kilobyte, but each level of increase in the prefix also increased the total discrepancy of the actual space compared to the advertised space.
Here is a quick reference to show the amount that the actual values differ compared to the advertised for each common referenced value:
• Megabyte Difference = 48,576 Bytes
• Gigabyte Difference = 73,741,824 Bytes
• Terabyte Difference = 99,511,627,776 Bytes
Based on this, for each Gigabyte that a drive manufacturer claims, they are over reporting the amount of disk space by 73,741,824 Bytes or roughly 70.3 MB of disk space. So, if a manufacturer advertises an 80 GB (80 billion bytes) hard drive, the actual disk space is around 74.5 GB of space, roughly 7% less than what they advertise.

Now, this isn't true for all the drives and storage media on the market. This is where consumers have to be careful. Most hard drives are reported based on the advertised values where a Gigabyte is one billion bytes. On the other hand, most flash media storage is based around the actual memory amounts. So a 512MB memory card has exactly 512 MB of data capacity, but this leads to the next area of reported space.

Formatted vs. Unformatted
In order for any type of storage device to be functional, there must be some method for the computer to know which bits stored on it relate to the specific files. This is where formatting of a drive comes in. The types of drive formats can vary depending on the computer but some of the more common ones are FAT16, FAT32 and NTFS. In each of these formatting schemes, a portion of the storage space is allocated so that the data on the drive can be catalogued enabling the computer or other device to properly read and write the data to the drive.
This means that when a drive is formatted, the functional storage space of the drive will be less than its unformatted capacity. The amount by which the space is reduced will vary depending upon the type of formatting used for the drive and also the amount and size of the various files on the system. Since it does vary, it is impossible for the manufacturers to quote the formatted size. This problem is most frequently encountered with flash media storage over larger capacity hard drives.

Now that's what I call thorough.

The import settings are only applicable to tracks that you import directly from an audio CD.

The large files that are in .wav format... were they imported directly from CD using iTunes, or were they perhaps already .wav files that you simply imported into your iTunes library?

Highlight all of your WAV files, right click on one of them, and hit "Convert to AAC". It'll apply to all of them.

Ok... you should be able to convert those tracks within iTunes.
Since your prefs seem to be set properly now, just highlight the tracks you wish to convert, and choose 'Convert Selection to AAC' from the Advanced menu in iTunes.

This will create a new track, preserving the .WAV encoded track.
It's your choice if you want to delete the .wav track after the conversion.