Gyruss - Is it 'truly' stereo?

[myrmidon]

Hi Folks,

I am mulling over what I should do to my JAMMA cab (Midway / MsPac-style) for Gyruss. Currently I have a single speaker, so I am considering one of the following 3 options (from most to least effort):


Option 1 - Install an Additional Pair of Speakers (and sort out my adaptor)
My speaker is mounted in the center of the cab, so I could mount an additional pair of speakers to the left and right of it specifically for Gyruss. I already have a generic 'Konami JAMMA Adaptor', which has 2 pins for the 'second speaker', however, there is no way to 'disconnect' (via jumpers) the single (old existing) speaker, so I either need to modify the JAMMA adaptor so that I can disconnect it and optionally connect the 2 new speakers for Gyruss (this would need to be reversible seeing as I use this same adaptor for other Konami games that are 'mono' and they need to still work). Or, I simply build a 'Gyruss-specific' JAMMA adaptor with a dedicated 4-pin 2.54mm header for the stereo speakers and no connection to JAMMA pins L & 10 (the existing mono speaker on my JAMMA harness).

This option is the most work, but it provides me 'true' stereo for Gyruss and still proper support for all my other mono/JAMMA games.


Option 2 - Install a single additional speaker
For this option I would install a second speaker either directly in front or behind the existing speaker, but also along the 'center line' of the cabinet. I would then simply connect this to the existing 'second speaker' pins on my Konami JAMMA adaptor and hear all the sounds of the game (there would just not be any L-R separation to my ears)

This is the middle ground - I have the additional speaker for Gyruss, but do not touch my JAMMA harness or Konami JAMMA adaptor in any way.


Option 3 - Run Gyruss in Mono mode
This option is simply install the jumper onto the Gyruss PCB that merges all the sound and simply pipe that through my JAMMA harness to the existing center-mounted mono speaker.

This option is obviously by far the simplest, but these options lead me to the all-important question that I started off with in the subject field:


Is Gyruss 'truly' stereo?
In other words, is there any correlation between where stuff happens on the screen and which speaker one hears it through (eg: when things explode on the left (on the screen) do I hear that through the left speaker?) And if yes, is the effect so pronounced that it justifies my effort described in 'Option 1' above?


Cheers,

[eds1275]

For a true stereo sound, installing another speaker in line with the first will not help. You'd need to go side to side for the effect to be verynoticeable - and if the sounds are out of phase, then you will get some weird sound issues.

[opt2not]

You'll notice the music in Gyruss is truly stereo, but the sound effects aren't.

When listening to the music in mono, you'll notice some of the harmonizing chords are missing, at least that's what it sounds like on my setup, using a Jamma adapter that only puts out mono for this board.

[myrmidon]

Thanks for the responses opt2not & eds1275.

Based on this it seems that 'Option 2' is off the cards. I will take a listen to the music to hear the effect of the lost chords, but with the sound FX being mono anyway, right now I am leaning towards running the game in mono (unless the 'listen test' swings me otherwise) :-)

[eds1275]

Well there is a difference having a card that plays mono only, and one that sums to mono. If it is playing mono, then it plays only one channel of audio, hence missing some of the chords and harmonies etc. But if it sums to mono, then it combines left and right before playing it - if it was mixed well, you won't have any phase anomolies. You said you had a jumper option; seems like the safest, easiest place to start. Fire it up in stereo MAME and see if there's much of a difference.