Stereo left and right crossed

[retrosega]

I just noticed something really wierd. I decided to use one of those compact disc laser cleaners in my megacd 1. It went though the cleaning tracks fine. On the cd are a few more sound test tracks. When it came to testing sound from the right speaker the music came out of the left speaker on the tv, and when it tested for sound on the left, music came from the right speaker.

im using a cable from the stereo headphone socket on the megadrive 1 to the rca sockets on the tv. I checked the plugs, and the white was plugged into the white (for left) and the red to the red (for right). I checked the sound tests again....and still the left and right mixed.

edit... I just tried the same lens cleaner in my megadrive 2 / megacd 2 combo and the same thing happened. the left and right were mixed up. I tried different av sockets on the tv (brand new panasonic lcd) and same thing happened. So not the tv at fault. The lens cleaner tests fine in my hifi/surround system so not the cd at fault. the right comes from the right, and the left from the left.

So what is happening with the megadrive? are the inputs crossed? it cant be possible all this time that stereo sound from the megacd has always been mixed up???

[Joe Redifer]

Sounds like the CD is backwards, not the hardware you are playing it on. There is a good way to test with Thunder Force 2. You must go into the sound test and play track 05 I think it is. If you hear a constant instrument (like a synth string) coming out of the LEFT and only the left, then everything is hooked up correctly.

[retrosega]

The CD is fine. I've had it for at least 10 years and have used it on many different stereos, hi-fi, computers and the right and left sound tests are definitely correct on the CD. Thunderforce 3

I dont think there is a problem with the megadrive. but could there possibly be something thats causing the L and R to mix up in the megacd???

Thunderforce played fine.

[evildragon]

you know, i noticed this too! so it ISNT just me!

I have my Red in white, and my white in RED, on the TV, using REAL Sega Stereo AV cables, and the sound is CORRECT... I thought I was going crazy, but it did this on my model 1, and model 2...

[Joe Redifer]

Thunderforce 3


No, Thunder Force 2.

[retrosega]

yes....I tried Thunderforce 2.

Now some developments..... instead of using a cable straight from the headphone socket to the TV, I used the connector cable that comes with the megacd1 to connect from the headphone socket from the megadrive1 to the mixer input on the back of the megacd1. then used normal RCA lead from the megacd 1 to the TV. Guess what!?!?!?! The sound came out from the correct speakers! L from L and R from R. But when I unplugged the mixer cable and used the cable straight from the megadrive 1 to the TV the sounbd was mixed again!

Could it be that Sega knew of this problem and released the megacd 1 with the mixer cable and used the megacd1 to correct the problem? But then the problem also exsists in the megadrive2/cd2 combo, and there is no mixer cable to connect between the 2 units. But the obviously made no attempt to fix it in version2.

Hopefully other people can test their units and comment on this.

[David J.]

if I could get an iso to test for audio channels, please let me know, so I can test it. :)

[retrosega]

Any CD audio cleaner should have sound tests on them. Even the really cheap ones in the bargain bins. Otherwise Ill try and put the iso up.

[Joe Redifer]

Download the zip file linked below to get an uncompressed WAV file you can burn to an audio CD to test your channels. As a zip file it is only a little over 3 MB. I'll post back soon with my findings as I just burned it to disc myself.

Click to download (http://pixelcraze.film-tech.net/crap/stereo_test.zip)

[Joe Redifer]

OK I just checked my systems. All is fine. Left is left and right is right even when I unplug the mixing jack and take the audio straight from the headphone jack. I am using a US Genesis 1 and a US Sega CD 1. Do you live in the UK? I have heard that companies mess things up for the UK on purpose because they don't like how ugly Prince Charles is.

Maybe your wire is at fault. Also, I checked Thunder Force 2 and it is music selection 03 and not 05 that I meant. When playing track 3 in that game, the proper true left should have it's own constant instrument that is not in the right.

Evildragon, if there is indeed a problem with the Sega CD or Genesis, then you only have it hooked up properly for the Sega CD... the Genesis will be backwards.

[retrosega]

I had the same crossed results with

Megadrive 1 (Jap) & MegaCD 1 (Australian) (no mixer cable)
Megadrive 1 (Australian) & Megacd 1 (Australian) (no mixer cable)
Megadrive 2 (Australian) & Megacd 2 (Australian) (I dont believe there is a mixer input)

The only time the L and R worked was using the mixer cable.

Is there a site i can upload the ISO of my soundtest cd?

[David J.]

I checked my Model 1 Genesis + Model 1 CD, it's fine. I checked my Model 2 system (Model 2 Genesis + Model 2 CD + 32X) and it's fine also.

At least the front tires aren't on the back, and the back tires aren't on the front.

[evildragon]

OK I just checked my systems. All is fine. Left is left and right is right even when I unplug the mixing jack and take the audio straight from the headphone jack. I am using a US Genesis 1 and a US Sega CD 1. Do you live in the UK? I have heard that companies mess things up for the UK on purpose because they don't like how ugly Prince Charles is.

Maybe your wire is at fault. Also, I checked Thunder Force 2 and it is music selection 03 and not 05 that I meant. When playing track 3 in that game, the proper true left should have it's own constant instrument that is not in the right.

Evildragon, if there is indeed a problem with the Sega CD or Genesis, then you only have it hooked up properly for the Sega CD... the Genesis will be backwards.
i tried through the Sega CD's output, and it is CORRECT.. but through the Genesis, it's backwards for me... I noticed in Colums (Genesis version), it's backwards too.. when switching the blocks on the left side of the screen, it's sound is on the right.. so freakin weird!

but when i went to the flea market today, and they had Columns playing on a Genesis 1 there (looked EXACLTY the same as mine), and with headphones it was CORRECT.. (mine was incorrect with headphones too)..

how freaky is that?

[retrosega]

Maybe, its a problem only with Australian megacd1 and cd2????

I think the megadrive itself is ok with its output, and the audio only crosses when its coming from the cd unit to the megadrive

[Joe Redifer]

Someone has some wires crossed somewhere, like I suggested before.

[David J.]

I played Thunder Force 2, and track 3 played just like it should have. I have my Genesis hooked up to a TV also, and it's fine. Maybe your TV has a reverse stereo function or something? I dunno.

Well, this is important if you drive an automobile. If you have the left tires on the right, and the right tires on the left, bad things can happen. Now, if you have the left tires on the right, and the right tires on the left, AND the front tires on the back, and the back tires on the front, then you're fucked!

[Joe Redifer]

I'll never rotate my tires again!!!

[evildragon]

the wires would be crossed internally then.. because i've never seen this issue happen, especially on UN-MODDED systems... I'm talking RIGHT from the headphone jack even gives backwards sound...

but also of interesting note, some AV cables have them backwards too! (either to compensate, or because of an oops).. seems like no one really cared then about what's left or whats right..

[Joe Redifer]

I sure did. I'm anal that way. Most people wouldn't have cared. But if there aren't at least some people who care about simple details, then I think the world would be a whole lot more sloppy (best word I could think of).

[evildragon]

oh i care about the left and right myself.. but what sucks, most of the gamers then, didn't even know HOW to hook a system up, and mostly used RF...

I noticed the sound was backwards when i played Chaotix.. I played it on the emulator, and was used to a specific drum beat on the right channel.. then when i got the game and heard it on the LEFT channel, I was like "WTF!!".. and ever since then, it seems to be left, right, left, right.. And the Sega CDs are affected by it especially..

I personally think this was an audio amp chip error, because the circuitry looks virtually identical.. i wonder if there was a bad batch..

[David J.]

I bought some el-cheapo phono cables at the dollar store, and aren't wired wrong. I use them with my Model 1 Sega CD, and no complaints. I bought some $3 ones at big lots, and they are OK, except one of the plugs gets easily stuck.

[evildragon]

ok, i think this needs to be tried.. and WITH a Sega CD..

The Test, using Columns, and Joes WAVE files on an Audio CD...

Using AV Cable:
Check which channels with Joes CD.
When in Columns, makes sure the "swooshing" sound when changing the columns, with the piece on the far left, happens only on the left speaker...

Using Phono cables on the Sega CD itself (without mixing cable):
Check which channels with Joes CD.

Using Phono cables on the Sega CD itself (WITH mixing cable):
Do the same test as with AV cables..

Mark a "check" if they are correct, mark an "X" if the channels are wrong.. It doesn't matter which version of Columns you use, because the Cart, and CD version still use the Genesis sound hardware (I think PSG for the "swoosh")

[retrosega]

Hi all, Ive done some extensive tests with different combinations and different leads and I've discovered that it was my 3.5mm to RCA cable at fault with the megadrive 1 / MegaCD 1 setup, and the stereo AV cable for the megadrive2/cd2 was at fault.

I didn't bother with columns.

I checked the hifi and tv and sound tests were correct with my CD and Joes wavs.

Now on to results.

Test 1 - Megadrive 1 (Jap)/ MegaCD 1 (pal), 3.5mm to RCA cable no.1, from headphone port. (no mixer cable) - left and right were crossed

Test 2 - Megadrive 1 (Jap)/MegaCD 1 (pal), 3.5mm to RCA cable no.2, from headphone port. (no mixer) - left and right were CORRECT!

.....this indicated the cable no.1 was at fault and was wired incorrectly at the factory. Yes I checked the white and red were matching.

Test 3 - same hardware, 3.5mm to RCA plug adaptor and stereo RCA cables from headphone port. Left and right were CORRECT!

Test 4 - Megadrive 1 (PAL) / Megacd 1 (pal). I tried both 3.5mm to RCA cables and got the same result as above - hence I can conclude that my original 3.5mm to RCA cable was at fault.

Test 5 - Megadrive 2 (pal) / Megacd 2 (pal). I used a stereo AV cable that I got off ebay. The sound tests were crossed!

Test 6 - Megadrive 2 (pal) / Megacd 2 (pal). Stereo RCA cables from RCA sockets from MegaCD 2. Left and right were correct!!

.....Conclusion is that the stereo AV cable that plugs straight in the back of the megadrive 2 (which I got off ebay) was wired incorrectly!


EvilDragon ..... most likely it is your cable at fault!


I have uploaded the soundtests of my cd here

http://www.esnips.com/web/megadrivesoundtest

Cheers!

[evildragon]

retrosega: It wouldn't be MY cable at fault if I hear the fault directly from the headphone jack on Some Genesis (and not on others with SAME headphones).. That's an internal wiring problem..

[Joe Redifer]

Maybe you are wearing your headphones backwards when plugged into some Genesis's but not others? :)

[evildragon]

Maybe you are wearing your headphones backwards when plugged into some Genesis's but not others? :)
ha-ha, very funny ;) (they can't go on backwards, the way they are designed wouldn't allow it)

[retrosega]

Evildragon - is your audio only crossing in some of the cartridge games, or also in megacd games?

I will test columns. Maybe its your Columns cartridge????

[evildragon]

it happens to almost everything.. i doubt a cartridge will cross the audio like that...

im telling you, it's a bad genesis..

[David J.]

I tested the ISO with my Model 1 Sega CD when I modded my transcoder (since you won't get audio with the Genesis 1, I used the Genesis 2) and I can tell you I modded correctly. :)