CMI 8738 AC3 Playback Problem

[Budginator]

Hi all,

I have a Cmedia 4 channel card with the 8738 chipset. I also have a few problems! :(

I am running Win98SE.

Q1- In Power DVD v3.0 i can select either '4channel output' 'wave out' or 'directsound'. 4 channel works, as in, it is surround sound, but the rear channels are slightly fuzzy. Fuzzy enough to be annoying. Wave out works, but its not surround sound, and its WAY to quiet with all volume controls on my PC maxed. Is there any way to fix this problem? The speakers are ONLY fuzzy in 4 channel mode.

Q2- I have an AC3 on my HD (i am using an ac3 extracted from the first 25mins of SPR for testing). I can play this AC3 just fine in windows media player. It was only using the cyberlink audio decoder and this only had 'dolby surround' which i could tell, was not working in full 4 channel surround. If i play the AC3 in power dvd set to 4 channel mode (fuzzy rear channels) it plays fine IN surround sound.

So i read up in the forum and installed the intervideo filter from doom9's audiofilter pack. It installed fine, but AC3 playback was choppy, and when i went to properties i could only select 2 channel mode, with the rest being grayed out (SPDIF included). What else can i do? I'm sure people with 8738 cards can play AC3 DivX's in 4 channel mode...

Thanks for any help

budginator

[zedstrange]

Originally posted by Budginator
I have a Cmedia 4 channel card with the 8738 chipset.

Hi, i cant help the problem, but i have one of these cards. what sort of hardware have you connected this up to? to get the 4 channel surround output?

also FYI there is now a 6 channel version of this card from computer supermarket.com.au for $25 - not bad. should be able to pick one up from a computer store,its avery common line for OEMS.

spec is here http://www.protac.com.au/product/Audioexcel/index.html

[Budginator]

My mate has one of these 6 channel cards, I might see if he will swap it over for a day to test...

To answer your question zedstrange, I have a 'cheap' 5.1 surround system hooked up. Two normal cables running from the 'rear' and 'speaker' outputs on my soundcard, to the front and rear inputs on my speakers amp.

Maybe I should change my question a little, can anyone here play AC3 audio (DivX or on its own) on a CMEDIA 8738 4-chan card in 4 channel mode?

[zedstrange]

Originally posted by Budginator
I have a 'cheap' 5.1 surround system hooked up. Two normal cables running from the 'rear' and 'speaker' outputs on my soundcard, to the front and rear inputs on my speakers amp.

interesting. i will soon hook up my system to my Yamaha Rx520 as soon as i get a TV out card. (the cook wont approve any computer in the living room- but i will get away with just the box );)

then i might be able to help with the question.

hang on - i got a spare Teac Surround system (sony clone) collecting dust in the corner, and its got an AUX input (single 3mm plug). might have to give that a go when i have some time (next weekend) and i will let you know.

[Budginator]

Originally posted by zedstrange
might have to give that a go when i have some time (next weekend) and i will let you know.

Thanks zedstrange, that'd be great :)

[zedstrange]

Originally posted by Budginator
Thanks zedstrange, that'd be great :)

i finally had some time to have a good look at my 8738 card. it is a better one than i thought. it was just a crappy cheapest thing i bought 18 months ago. whilst its not the 6 channel 8738-LX one that is at the Protac site, mine is the 8738-MX (you can only tell this by looking at the chip on the card) with the following external connections
Line (blue) Mic (pink)
SPK (green) rear (black)
Spdif OUT

so my complete config is a CMI8738-MX running on WinXP, Duron1gb/256mb ram.

I hooked it up to my very ordinary surround amp, by connecting to SPK out with a adaptor converting what i think is called a 3.2mm pin to 2xRCA and connected to an Input (ie Left/right) on the amp.

without changing any setting at all (the Soundcard properties were still default as 'stereo' speakers) and it seemed to give me what seems very good surround sound on a DVD ripped to DIvX with an AC3 sound file. cant wait to hook this up to my Yamaha DSP amp.

i had a look at the sound properties and changed speaker type to '5.1 surround' and then played a Divx with MP3 sound track and still gives good surround sound. (as an afterthought i dont beleive the speaker type needs changing from stereo as i am outputting the sound into a Dolby pro logic amp)

now i had a look at Power DVD 4.0 playing back a DivX with AC3 sound. on default audio setting of '2 speaker' and 'stereo' the surround sound is still quite good. i then changed it to 4 speaker and the surround sound became very passive, and some of the sounds i expected to be behind me were not. changing the settings under the '2speaker' setup didnt seem to make any difference.

i wonder if you would experience any difference if you hooked up two sets of powered PC speakers directly to the SPK and REAR outs on the card, and see if it makes any difference, maybe its just the AMP thats causing the issues for you.

I havent installed the intervideo pack, and i dont want to :-) everythings working fine for me so it seems, so i dont wanna wreck it.

BTW every time above when i mentioned surround sound, i am referring to the rear channel and relating it to what i expect.
cheers mate

[Budginator]

Hi zedstrange, thanks for having a look at your card for me :)

http://members.optusnet.com.au/~big_em/budge/cmi8738_chip.jpg

I have looked at mine (the pic is of the cards CMI8738 chip) and it does not say whether its an MX or an LX...

Anyway, when you say you hooked your card up to your pro-logic amp does that mean that its reproducing the front left and right channels and putting them throught the rear speakers? Not plugging in the two front channels and two rear channels seperatly?

I plugged a pair of headphones directly into 'rear out' on my card, and i got the same shitty 'fuzzy' sound as i was getting with the rear speakers, so its not my amp... it must be the card itself.

I'm starting to think its my drivers... I have version 4.06.1096 installed, but the install of 98 i'm currently running dates back over a year and i have updated the drivers a few times over that time. I think something has gone wrong along the way. Its time for a complete format and reinstall of the OS anyway (i'm on uni holidays so i've got the time :)) Hopefully this will fix it, and I will be dual booting 98SE and XP so i'll have to get the newest drivers for each OS.

I'm sure i have a $125 speeding fine on the way as well, so there goes my planned new 6ch card upgrade :(

thanks again mate

[zedstrange]

you must have the older version of the chip.

i connected two sets of PC speakers, one to SPK and the other to REAR outs on the card, and exactly the same sounds were reproduced from each (i proved that by removing the SPK connection and there was no loss of sound) so there was actually no 'rear' effect even though i did change the Speaker properties to surround, and also no quality loss.

to be honest i dont think its your drivers, i reckon the REAR connection is RS. if it was the drivers the other outputs would be the same.

i didnt plug in the front and rear channels seperately from the card. i just connected the SPK out (green) direct to an RCA (left/right)input on the Amp. you just need an adaptor, might be just the thing for ya. i was actually surprised this worked, as i was only expecting a left and right stereo effect.

cheers

[Budginator]

Ok thanks you for your help zedstrange.

I will be testing the 6 channel version of this card soon, i'll see if i get any change.

Also... what DVD did you test with? One with alot of surround effects (like SPR?). I still don't really understand how you got 'surround' sound from only using SPK out.

Do you have any AC3 DivX's? If so what application do you play them with?

cheers again mate

[zedstrange]

Originally posted by Budginator
Also... what DVD did you test with?

Independence Day. it has a good exploding Title shot at the opening credits that goes from front to rear.

I still don't really understand how you got 'surround' sound from only using SPK out.[/B]

i wouldnt have a clue either. i am just a monkey see monkee do person in this area.maybe its becuase i am outputting via dolby decoder amp that does the trick

Do you have any AC3 DivX's? If so what application do you play them with?

Yes, i have done most of mine in Ac3, and i do the kids movies in MP3 and even they are in surround.
I play them in media player 8

[Budginator]

Thanks for answering my questions again zedstrange, i'm trying to encode The Blue Planet now, which is only 2channel audio so surround doesn't matter for the moment :)

cheers mate

[zedstrange]

i just picked up another soundcard for $18 from my local supplier. the Brand name is Mercury and it sells as a 6 channel card. There is also a 4 channel for $14.

when i got it i was impressed that its the lasted cmi8738 chipset. it has no SPdif out, but has 3 outputs as follows

normal speaker or front surround
rear
centre/Lfe.

havent set it up yet, but i assume its going to be ok to connectdirect to my amp in the 5 channel direct input connections. dont know who the combined centre/lfe output will work though but i can only try

[MaTTeR]

Originally posted by zedstrange
dont know who the combined centre/lfe output will work though but i can only try

Typically you can just use a mini-jack 2channel cable and it seperates the center and LFE. I think almost all Cmedia cards are setup like this.

[zedstrange]

Originally posted by MaTTeR


Typically you can just use a mini-jack 2channel cable and it seperates the center and LFE. I think almost all Cmedia cards are setup like this.

thanks. i dont really know what a mini-jack 2 ch cable is, but i have some adaptors that are single 3.5mm plug to twin RCA. is that what you meant?

i just figure when i hook that up one will be for Centre and the other for LFE

[MaTTeR]

Originally posted by zedstrange


thanks. i dont really know what a mini-jack 2 ch cable is, but i have some adaptors that are single 3.5mm plug to twin RCA. is that what you meant?


Sorry, I should have mentined that mini-jacks are the 3.5mm plug that you mention. Sounds like what you have should work fine.

[bond]

Q1- In Power DVD v3.0 i can select either '4channel output' 'wave out' or 'directsound'. 4 channel works, as in, it is surround sound, but the rear channels are slightly fuzzy. Fuzzy enough to be annoying. Wave out works, but its not surround sound, and its WAY to quiet with all volume controls on my PC maxed. Is there any way to fix this problem? The speakers are ONLY fuzzy in 4 channel mode.

Q2- I have an AC3 on my HD (i am using an ac3 extracted from the first 25mins of SPR for testing). I can play this AC3 just fine in windows media player. It was only using the cyberlink audio decoder and this only had 'dolby surround' which i could tell, was not working in full 4 channel surround. If i play the AC3 in power dvd set to 4 channel mode (fuzzy rear channels) it plays fine IN surround sound.

So i read up in the forum and installed the intervideo filter from doom9's audiofilter pack. It installed fine, but AC3 playback was choppy, and when i went to properties i could only select 2 channel mode, with the rest being grayed out (SPDIF included). What else can i do? I'm sure people with 8738 cards can play AC3 DivX's in 4 channel mode...dunno if its the same issue, but i found the reason for potential cracking sound with this setup described here (http://forum.doom9.org/showthread.php?p=699605#post699605)

[HalfHuman]

loose that 8738 sound card. it is only good if u use it like a stereo sound card. i have a sound card sold out like yamaha724. based on the same chip they made yamaha 744 and 764 and guess what they were 4 and 6 channel. but what sound did they produced. it wasn't quadrophonic and neither 5.1 it only was a stereo sound doubled or tripled.
i haven't read the entire post but the model of the chip caught my eye.
so as a work of wisdom: do not expect to have surround sound with 15$ sound card!!!
get a card made by a true audio card manufacturer like cretive, hercules etc and u will be able to get a true surround card for 50$ or higher. else use the onboard sound.

and another thing the marvelous card that i own and that sounds quite fine in stereo was recognised ok by win me. when i went to win xp pro i had a little surprise. there were no drivers for win xp and boy did i had a good time searching for drivers. ifinally found out that my audio card was not manufactured by yamaha, but by some noname party wich modified the drivers so the sound card appeared to be made by yamaha. just needed to share my oppinion with you.

[zedstrange]

If you look around you will find that the CMI 8738 is a card highly recommended.

Somewhere on this forum is also a topic,post or FAQ that creative is one that you shouldnt buy - particualarily for recording.