Sega Genesis/Mega Drive Audio Quality Test

Sega Genesis/Mega Drive Audio Quality
http://genesisaudio.protoman.com/

Contents

Introduction
Method
Noise Reduction Profile Graphs
1. Data
2. Analysis
Subjective Testing
1. Listening Test
  1. Gunstar Heroes
  2. Streets of Rage 2
2. Placebo Elimination Test
Conclusion
File List
Contact

Introduction

In order to clear up some of the uncertainty surrounding the recording of Sega Genesis/Mega Drive audio directly from the unit, I have made sample recordings from each North American Genesis model except the Genesis 3.

Genesis 1 (1601) serial number: 021225211
Genesis 2 (MK-1631) serial number: 140036139
Nomad (MK-6100) serial number: 050046583
(Note: Pictures are not of my units and are intended only as a representation of their appearances.)

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Method

For those models with 1/8" stereo miniplug/headphone ports, I recorded two samples at approximately 50% of the maximum volume of the port, then two more samples at maximum volume. The approximate 50% volume level for each unit was identical for each recording.

The samples were recorded starting before the system was turned on. Navigation to the desired song in the sound test was also recorded. One recording from Gunstar Heroes and one recording from Streets of Rage 2 (Bare Knuckle II) were made with each configuration. The track selected from Gunstar Heroes was the Main Title theme by Hanzawa Norio. The track selected from Streets of Rage 2 was the Boss music ("Never Return Alive") by Koshiro Yuzo. Additionally, for Streets of Rage 2, Stage Clear, also by Koshiro Yuzo, was used to bring the end of the recording to silence.

The waveforms were recorded using the purple RCA input adapter for an All in Wonder 9600 capture card. The 1/8" miniplug audio output of this card was in turn plugged into a SoundMAX Digital Audio motherboard-integrated sound "card." The All in Wonder's sound output was plugged into the SoundMAX's line-in port, and the recording level of the port was set to 1 unit above silence using the Microsoft Windows mixer.

The recording software used was Cool Edit Pro 2.0. Two channels of 16 bit samples were recorded at 44,100 Hz.

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Noise Reduction Profile Graphs

Data

Five seconds of "silence" were selected from near the end of each recording in Cool Edit Pro 2.0, then captured for a Noise Profile. The right and left channels of this Noise Profile are displayed below. (Hint: To easily compare the graphs, try opening them in new tabs.)

Genesis 1 Headphone Port Approximately 50% Volume
Gunstar Heroes
Left Channel	Right Channel


Streets of Rage 2
Left Channel	Right Channel

Genesis 1 Headphone Port 100% Volume
Gunstar Heroes
Left Channel	Right Channel


Streets of Rage 2
Left Channel	Right Channel

Genesis 2 Stereo AV Cable
Gunstar Heroes
Left Channel	Right Channel


Streets of Rage 2
Left Channel	Right Channel

Nomad Headphone Port Approximately 50% Volume (AC Power)
Gunstar Heroes
Left Channel	Right Channel


Streets of Rage 2
Left Channel	Right Channel

Nomad Headphone Port Approximately 50% Volume (DC Power)
Gunstar Heroes
Left Channel	Right Channel


Streets of Rage 2
Left Channel	Right Channel

Nomad Headphone Port 100% Volume (AC Power)
Gunstar Heroes
Left Channel	Right Channel


Streets of Rage 2
Left Channel	Right Channel

Nomad Headphone Port 100% Volume (DC Power)
Gunstar Heroes
Left Channel	Right Channel


Streets of Rage 2
Left Channel	Right Channel

Nomad Stereo AV Cable (AC Power)
Gunstar Heroes
Left Channel	Right Channel


Streets of Rage 2
Left Channel	Right Channel

Nomad Stereo AV Cable (DC Power)
Gunstar Heroes
Left Channel	Right Channel


Streets of Rage 2
Left Channel	Right Channel

Analysis

The noise profile graphs do not show a clear winner, only that the nature of the noise is different between different units. One can only expect from looking at these graphs that the audio will sound different on different units, not make any conclusions about which unit should sound the best.

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Subjective Testing

Listening Test

Because the Cool Edit Pro 2.0 noise profile graphs did not seem to show a clear winner in terms of audio interference, a subjective listening test was necessary. I made the subjective evaluations of each recording's audio quality while listening to the test files using stereo headphones.

Note: I was originally only going to compare the 100% volume headphone jack recordings with the AV cable recordings, where applicable. However, after I noticed that the recording of the Nomad's headphone port at 100% volume was overpeaked, I decided to normalize the approximately 50% volume level recording of Streets of Rage 2 and compare it to the AV cable recording of the same. The Nomad audio sounded so similar through its headphone port and AV cable that I wanted to make sure that I was judging them fairly.

Gunstar Heroes

Genesis 1 Headphone Port 100% Volume

Overpowering noise throughout intro. The texture of the noise covers the textures of all instruments in all ranges. No true bass is apparent. Incredibly altered sound effect in the finale.

Genesis 2 Stereo AV Cable

Vastly improved high ranges, but bass still suffers. Intro is much better than the rest of the track due to the intro being mostly free of bass. Bass distortion also affects other low ranges. Better finale.

Nomad Headphone Port 100% Volume (AC Power)

Music sounds slightly overpeaked. High ranges brilliant and clear. Dramatically better bass. Remaining distortion does not affect other ranges.

Nomad Stereo AV Cable (DC Power)

Level sounds correct, much better than previous example. Better balance between bass and treble. Very little audible noise in finale.

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Streets of Rage 2

Genesis 1 Headphone Port 100% Volume

Severe distortion in many ranges, especially bass, which is reduced to a kind of rapid clicking. Hiss is omnipresent. "Silence" is marked by noise mostly audible at high frequencies.

Genesis 2 Stereo AV Cable

Higher frequencies clearer than previous example, but bass is still badly distorted. "Silence" is much clearer than the previous example, with noise only a quiet whisper in the midrange.

Nomad Headphone Port 100% Volume (AC Power)

Bass much cleaner than previous two examples, and other ranges remain clear. "Silence" sounds like AC hum (60 Hz). Very loud, clear noise.

Nomad Stereo AV Cable (DC Power)

Less noise during opening sequence. No noticeable distortion in the bass. "Silence" sounds like a much quieter AC hum, very distant and difficult to pick out.

Nomad Headphone Port Approximately 50% Volume, Normalized (AC Power)

No audible distortion in intro. High range crystal clear. Noise very audible during "silence," same distant AC hum-like sound as with the AV cable.

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Placebo Elimination Test

In order to make absolutely sure that biases were not interfering with my ability to subjectively grade the music, a test was done to eliminate any chance of the Nomad winning via placebo. Three Streets of Rage 2 test files (the Genesis 1 headphone port at 100% volume, the Genesis 2 AV cable, and the Nomad AV cable with DC power) were renamed M81aA{$}.wav, uA0}(h=8.wav and )K{w-)rt.wav, respectively, by a third party. I was not able to view the process of renaming while it occurred.

I then burned the renamed files to a CD and listened to them. I was able to correctly identify which system produced which audio track, even though the Genesis 1 and 2 had sounded so similar to me in the earlier Listening Test. Again, the Nomad audio was clearly superior to the other two: I identified it instantly. The Genesis 1 and 2 files were more difficult to tell apart, because they were both severely distorted.

I interpret this as conclusive evidence that my Nomad offers far and away better audio quality than either my Genesis 1 or Genesis 2.

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Conclusion

Though it is possible that the results of these tests do not accurately reflect those of average Genesis consoles, I believe that they present a very convincing case for the superiority of Nomad audio output. I implore you to at least try recording with a Nomad to see if the sound quality is appreciably better to your ears.

I recommend that you try recording first with a stereo AV cable, then switch to an 1/8" miniplug only if you have problems with overpeaking. If it is true that the volume control on the Nomad is a digital one, then you will want to always record with 100% of the available volume (an AV cable's volume level is always 100%). However, because I was not able to discern a significant difference between Nomad audio from an AV cable and from its headphone jack when it was recorded at approximately 50% volume, I believe that there would be little harm done by switching to the headphone jack if necessary (and turning it down to avoid overpeaking). Of course, it is always important to check that the signal is not overpeaking your equipment.

Both Nomads and stereo AV cables can be purchased on eBay. As of this writing, fully functional Nomads were selling for about $100 US, while stereo AV cables were selling for about $10 US. However, one can sometimes find Nomads with one or more problems, e.g. a broken screen, which might make them significantly cheaper. (A nonfunctional screen is no problem for recording, as you can simply plug the composite video cable into a TV or capture card and see what you are doing that way.)

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File List

Genesis_1_Headphone_Port_About_50_Percent_Volume_Gunstar_Heroes.wav
Genesis_1_Headphone_Port_About_50_Percent_Volume_Streets_of_Rage_2.wav
Genesis_1_Headphone_Port_100_Percent_Volume_Gunstar_Heroes.wav
Genesis_1_Headphone_Port_100_Percent_Volume_Streets_of_Rage_2.wav
Genesis_2_Stereo_AV_Cable_Gunstar_Heroes.wav
Genesis_2_Stereo_AV_Cable_Streets_of_Rage_2.wav
Nomad_Headphone_Port_About_50_Percent_Volume_AC_Power_Gunstar_Heroes.wav
Nomad_Headphone_Port_About_50_Percent_Volume_AC_Power_Streets_of_Rage_2.wav
Nomad_Headphone_Port_About_50_Percent_Volume_DC_Power_Gunstar_Heroes.wav
Nomad_Headphone_Port_About_50_Percent_Volume_DC_Power_Streets_of_Rage_2.wav
Nomad_Headphone_Port_About_50_Percent_Volume_DC_Power_Streets_of_Rage_2_Normalized.wav
Nomad_Headphone_Port_100_Percent_Volume_AC_Power_Gunstar_Heroes.wav
Nomad_Headphone_Port_100_Percent_Volume_AC_Power_Streets_of_Rage_2.wav
Nomad_Headphone_Port_100_Percent_Volume_DC_Power_Gunstar_Heroes.wav
Nomad_Headphone_Port_100_Percent_Volume_DC_Power_Streets_of_Rage_2.wav
Nomad_Stereo_AV_Cable_AC_Power_Gunstar_Heroes.wav
Nomad_Stereo_AV_Cable_AC_Power_Streets_of_Rage_2.wav
Nomad_Stereo_AV_Cable_DC_Power_Gunstar_Heroes.wav
Nomad_Stereo_AV_Cable_DC_Power_Streets_of_Rage_2.wav

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Contact

Nathan Jahnke
njahnke@gmail.com
Last updated 9 June, 2005

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