CMVS sound issues with B&O MX7000

[metoo3]

Hi all,

Just received my first CMVS some time ago. Very happy so far but two little issues.

Once I connect the CMVS via Scart RGB to the MX7000 the picture is very good, no interference whatsoever.
When I connect it to my Panasonic Plasma via Scart the picture is as expected but every few seconds there is a horizontal interference on the top portion of the screen. Other Scart RGB cables make no difference.
Once I activate "intelligent frame creation on the TV, this problem disappears.
Any ideas what may cause this use?

Actually I would go for a XRGB-Mini anyway but it seems impossible to purchase at the moment.

Once I connect the CMVS to the MX7000 the music is very good. Sound effects e.g. gun shooting in Metal Slug, voices or high pitch sounds seem overdriven. When I connect headphones to the MX7000's headphone jack, it's the same problem.
This same problem may not appear on the Plasma.
Cartridge Pins and MVS slot shiny without any issues.
Integrated sound test is fine. CMVS is MV1A.

Any ideas? These issues really bug me since I already spent way to much time on Internet to solve this...

Many thanks.

[LDigital]

I'm no expert but consolised my Own MVS so have a bit of experience. I think the issue you are seeing is due to the slightly off spec refresh rate of the mvs hardware. It won't show an issue on the analogue crt as it can handle it but the plasma is picking it up. The intelligent frame creation is probably filling in the gap

[metoo3]

That's also my expectation. I guess the Framemeister will solve this in case it will be available ever again...

Regarding the audio. How is it on your MVS? Do you know if Windjammers and Metal Slug voices and sound effects seem a bit overdriven? Maybe that's just the way it's supposed to be?!

[LDigital]

It's fine on mine. I reworked my 1fz to run off 5v by disabling the on board amp and rebuilding the audio for stereo. If you are using the stock circuit it could be over amplifying/driving it before it's reaching the tv amp

[Makinx]

Maybe you need to adjust the treble setting on the MX7000, although I suspect you already tried that.

[metoo3]

I already adjusted the treble settings.

However my Plasma set is doing some "magic" to get rid of this issue.

This afternoon I'll try on my PVM with external audio.

If no luck after all, I consider to take apart the CMVS to adjust the volume control knob.

[gray117]

er

Sound:

... anything else exhibit similar sound issues on mx7000?
Does the mx have any strange surround/stereo options? ... nicam? ...turn these off.

To try and circumvent; use and scart audio breakout (or audio phono out if cmvs has that) and hook up to some separate speakers.

I'd be skeptical that the plasma is 'fixing' anything audio wise, more that the mx is messing it up BUT depending on what mvs board (?) is inside there and how the audio is being tapped there is an off chance you're either getting unamplified audio ... though iirc audio from jamma edge on neo should be amplified.... or that something is wrong with how the the amplified audio is being taken back down to line level [presuming the cmvs is doing this]?

... If the cmvs is taking audio from jamma edge and not reducing to line level that's probably a bad thing, and the mx may be reacting to this differently than may be expected...

what cmvs is it exactly?



Interference on plasma:

The mvs has a slightly wierd refresh rate - like 59.2 vs the typical 59.9 or 60 iirc. I'd *guess* the tv is re-syncing and/or (attempts) to carry over a portion of one frame to another ... it's a shame intelligent frame creation fixes it since that'll increase lag (and looks wrong imho)... are there any other refresh rate options on the tv? What model is it exactly? ... there might be some kind of 60/100/144hz options that similarly circumvent the issue...

I take it the cmvs doesn't have a component output to test/compare?

It'd be interesting to see if a scart passthrough (+ maybe introduction of blanking signal) would help the issue... but that's not a guarantee... euro person? Try a vcr / dvd recorder with a scart passthrough, or any other similarly powered cheap device with scart passthrough.

Beyond that, yep investigating rgb upscanners like xrgb would be the (likely more expensive) route to explore.

[metoo3]

Thanks for getting back to this.

Sound:
My Dreamcasts on the MX7000 seem to be fine, no issues whatsoever.

The Scart audio breakout boxes I have tried are even worse. I could only find cheapo plastic stuff, causing lots of interference.
Board is MV1A, I don't know how the audio is being tapped. It should be possible to use the volume knob to modify the sound level.
The integrated audio test: "right" and "left" is similar in volume. "Center" is louder.

It's a very nice CMVS from a guy in Germany. This is his channel and the CMVS in the video seems similar to my one.
https://www.youtube.com/watch?v=iEzAe0YyXFQ


Plasma:
Panasonic TX-P50V10
No other refresh rate options, I couldn't even check the refresh rate. Tried both Scart inputs, game mode etc. no change.
CMVS has RGB Scart, no component output.
Passthrough would be interesting. I'll try to arrange an old VCR unit.


Tonight I'm gonna try the Scart to BNC with integrated Sync stripper and audio breakout on my PVM...

[gray117]

It's a very nice CMVS from a guy in Germany. This is his channel and the CMVS in the video seems similar to my one.
https://www.youtube.com/watch?v=iEzAe0YyXFQ

haha - Galaxy Fight - the German choice !?!

... Anyways ... well at 6:23 you can see him soldering audio to scart but can't work out if it goes via anything from the mvs edge. My only guess is that maybe the mx is has some kind of peak/tolerence if this is amplified audio - but that's purely guesswork. By rights it should just effect all your sound, but maybe there's something about sfx levels that I'm not grasping.

Beyond that I'd try my luck on getting finding a decently made audio break-out for use with mx. Unless anyone can recommend one they got recently...?

Good luck with it!

[metoo3]

Thanks for your reply.

I'm now using the CMVS on my PVM with audio breakout. On my external PC speaker it's less obvious.
Although on the MX7000 it depends on the general volume as well. It's getting more obvious once I raise the volume.

[gray117]

Well *assuming* I'm not totally off track, and everything's wired right...

... If it's still not as good as could be across everything I'd probably recommend this as a no-solder-user-friendly fix:
http://www.ebay.co.uk/itm/AAS40ASCRCA-4 ... SwPgxVLjaf

*I'm assuming audio break oout is rca, there are various other 2.5mm headphone input/ouput versions about too probably... And of course if solder-happy you can make yourself cheaply.

Minimum adjust is about -15dB (max @-40dB will probably kill off the audio ). Ideally something like this would have been part of the cmvs but to be fair unless as the creator you encounter a problem it's easy to overlook I suppose.

The suggestion is that about -20dB is about what you want:
http://www.neo-geo.com/forums/showthrea ... ALL-Sorted

[metoo3]

Many thinks for your efforts.

I'll order this attenuator straight away.

I'm still looking for a high quality RGB Scart cable with rca breakout but it seems complicated...

[EDIT]
I'll try these from Amazon since they would arrive during tomorrow. They offer -20db which schould be fine I guess.
https://www.amazon.de/IMG-21-2840-Pegel ... elminderer