MP3 (and All “Lossy” Digital Compression) Sound Enhancement and Restoration Getting Nice Vacuum Tube Sound out of Digital Compression
BBE MP (Minimized Polynomial Non-Linear Saturation) Process improves digitally compressed sound, such as MP3, by restoring and enhancing the harmonics lost through compression. BBE MP works by re-generating harmonics from the source material, effectively recovering warmth, details and nuance.

BBE MP extends the upper frequency range of MP3/WMA files to CD-range and a CD’s frequency range to Super Audio CD or DVD audio range. This is accomplished through over-sampling.
MP3 Player, MD Player, CD Player, Headphone Stereo, Mini-Component Stereo, Portable Stereo, Car Stereo, TV, Satellite Radio (XM, Sirius),
Internet Radio,Telephone, etc.
All Digitally Compressed (Lossy Compression) Audio and CD (PCM) MPEG Layer Audio (MP1, MP2, MP3), mp3PRO, MPEG4 Audio, AAC, ATRAC (MD),
AC-3, DTS, Sirius, XM, IBOC, CD (PCM), Telephone, etc.
Restores and enhances harmonics lost through compression.
Restores harmonics’ phase alignment.
Restores stereo image reduced by compression, and regain full-stereo performance.
Reveals the delicate and aesthetically delightful details in the music.
Restores warmth to the spoiled digitally compressed sound.
Expands the upper frequency range by over-sampling
Very Simple Digital Software (1/10 to 1/100 of comparable processes)
The digital compression is mainly performed in frequency domain. The above left waveform is sound wave seen on a scope. Sampled at the instant “A”, the spectrum of the sound is mapped like the above right, indicated as “Original”. This is essentially the sampling process. The sampled spectrum appears to be very complex. However, it is generally accepted that smoothing this complex curve does not greatly affect the sound, while reducing substantial amount (more than 90%) of data. The result is a smooth curve indicated as “Compression”. This is the core of digital compression. The sampling continues in the time domain at about 40KHz, generating the series of spectrum datum displayed below.
Besides the main frequency domain compression, the digital compression is performed in the time domain as well. After the both frequency and time domain compression processes, the spectrum datum are simplified as illustrated below. (Note: The illustration is overly simplified for easier understanding.) Thus, a huge amount of information is removed and permanently lost. (This is the reason why this type of compression is called “Lossy” Compression.) Moreover, MP3 often uses a lower sampling rate than a CD, which creates a total loss of information above the specific frequency (1/2 of the sampling frequency). Note the sudden information loss over the specific frequency in the illustration below. The specific frequency also varies depending on the contents of frequency spectrum.
The sound reproduced from this data file sounds okay, a piano still sounds like a piano and a trumpet sounds like a trumpet, but the details, nuance, and musicality are lost. The sound becomes rather dull. BBE helps to restore and enhance the sound by detecting the reduced harmonics, boosting them and correcting the time alignments. However, if the harmonics are completely lost, they must be regenerated.
The MP (Minimized Polynomial Non-Linear Saturation) Process effectively generates harmonics indicated as “ Generated Harmonics by MP Process ” from a “ Fundamental ” note in the illustration below. The even order harmonics create harmonized, warm and comfortable sound, while the right amount of odd order harmonics makes the sound brighter and sharper, when they are added to the original sound. The result is a warm and comfortable, yet distinguished sound. [This mechanism is similar to a vacuum tube amplifier, which also tends to generate even-order and odd-order harmonics, which is why a vacuum tube amplifier sounds warmer and more comfortable than more advanced modern solid state amplifiers.
This MP process performance covers the entire audio bandwidth, evenly from low to high frequencies, without enhancing or coloring any particular frequency range. The spectrum file, after adding the regenerated harmonics, is shown below. By using a higher sampling rate, the MP process can even regenerate audio signals to fill the once completely-lost high-frequency range.
The BBE Process, which provides a linear phase advance in proportion to the frequency, is placed before the MP process. The MP process evenly generates higher harmonics from the entire audio bandwidth. Since the BBE-processed sound has a tapered time alignment (the higher the frequency, the more time advance), the generated harmonics are time-advanced in the higher frequencies. This allows the brain to analyze the sound more easily with the least amount of added harmonics. (It is common knowledge in the psycho-acoustic studies that time-advanced harmonics, compared to fundamentals, make the brain’s interpretation of sound easier.)
The BBE process progressively enhances the higher frequencies. The harmonics generated by the MP process tends to have more elements in the higher frequencies compared to the lower frequencies. The degree of this contrast is optimized by the BBE process gain.

The BBE MP process turns digitally compressed and spoiled sound into a warmer and richer sound with more details, clarity and sharpness.
MP3 data contains a minimum amount of information attempting to reproduce the sound in an acceptable quality. A mere 1/20 of the original information is kept and the rest is permanently discarded. (Instead, you can store 20 times more music in the same media.) The narrowed frequency range is another tactic to compress the file size. It is noticeable that the MP3 music obviously has less high-frequency information compared to CD music. This is a common problem to any digitally compressed audio including WMA.
The BBE MP process not only restores the harmonics within the band but also extends the high frequency bandwidth up to 24KHz or 48KHz, as shown below, through over-sampling at 48KHz and 96KHz respectively.
The pictures below show a part of the frequency spectrum of “I Remember You” by Dianna Krall, illustrating the effect of the BBE MP process. The upper picture shows the test material with no information above 16KHz. The higher frequencies were removed by down-sampling the original CD at 32KHz. The lower picture illustrates the BBE MP process regenerating the harmonics over 16KHz when it is applied to the frequency-limited test material. The effect is obvious at the beginning of every beat. The center of the picture indicates a large amount of harmonics over 16KHz being generated from the 6KHz-8KHz information.
The pictures on this page are details (one beat) of the previous illustrations. Although it is not clearly visible (due to display and/or print quality), even the darker regions of the lower illustration have very subtle regenerated harmonics. This is true throughout the entire song.
The following three pictures, corresponding with the pictures on the previous page, show the frequency analysis at the same time-position. The first picture shows the frequency response of the original CD in which the upper frequency limit is 22KHz. The second picture is the frequency limited MP3 test material which contains no information over 16KHz.
The third picture (below) shows the result of the BBE MP process. All signals over 16KHz have been regenerated by the MP process. The upper frequency is thus extended to 24KHz which is even higher than the original CD’s 22KHz limit. In respect to the original CD, the frequency response is well restored.
This result is similar to mp3PRO decoding. The difference is that the mp3PRO decoder works only on its own encoded materials whereas the MP process works on both MP3 and mp3PRO materials, as well as on all digital audio formats including WMA and AAC.
The CD provides good quality sound for normal audio applications. However, the new Super Audio CD or DVD audio exceeds the CD’s quality by far. This is because of its higher sampling rate (wider bandwidth) and greater number of audio bits.
BBE MP extends the high frequency response of CDs to the level of Super Audio CD or DVD audio. This is realized by over-sampling. The figure above shows the CD’s upper limit of 22KHz being extended to 48KHz by over-sampling at 96KHz. The sound becomes smoother with the increased details.

The waveforms on the next page are details from Emmylou Harris’s “I Still Miss Someone.” The upper picture shows a WAV file obtained by re-sampling the CD at 44KHz ? an exact copy of the original CD. The bottom picture shows the result of the BBE MP process, slightly over-sampled at 48KHz. Quite a few high frequency elements (small vibrations) are seen riding on the large waves. These are the harmonics generated by the BBE MP process.
This is an example of vintage recording restoration using the BBE MP process. The first picture is Peggy Lee’s 1941 original recording (recently digitally re-mastered for CD) “On the Sunny Side of the Street.” The part in detail is a few beats of Benny Goodman’s clarinet. This old SP recording has absolutely no information above 10KHz. The second picture illustrates the BBE MP process generating the higher harmonics all the way up to 20KHz. Perhaps Benny Goodman’s clarinet sounded like this originally, but it had never been recorded.
The following two pictures, corresponding with the pictures on the previous page, show the frequency analysis at the same time-location. The first picture shows the frequency response of the original recording. No information above 10KHz were recorded. The second picture shows the result of the BBE MP process. All signals over 10KHz have been regenerated by the MP process. The upper frequency is extended to 20KHz.
The distinctive sound of a telephone is caused by its narrow bandwidth, especially by its relatively low 4KHz frequency limit which degrades its clarity.
The MP process extends the 4KHz upper frequency limit through over-sampling. The figure above illustrates the 4KHz upper limit being extended to 8KHz by re-sampling the signal at 16KHz instead of the normal 8KHz. The normal 300Hz ? 4KHz bandwidth is expanded to 300Hz ? 8KHz. By combining the MP process with the BBE T2 (Telephone Technology) process, both clarity and intelligibility are dramatically improved.