P5GD2 Deluxe Sound
 

Can I connect speakers to the gray (LS/RS) socket without an amplifier? I
have tried this and the sound is almost inaudible. The same speakers, cables
etc. are fine when I use the green (L/R) socket.

Thanks
Martin

In article , "Martin Chatfield"
wrote:

Can I connect speakers to the gray (LS/RS) socket without an amplifier? I
have tried this and the sound is almost inaudible. The same speakers, cables
etc. are fine when I use the green (L/R) socket.

Thanks
Martin

I downloaded the datasheet for the CMI9880 chip, and the
datasheet claims there is 32 ohm headphone drive available
on each port. What is unclear, is whether the software
will enable all of them at the same time, or has the
notion of only supporting that drive on one selected
pair of channels at a time.

In the "old days" of AC97, the stereo Lineout had 32 ohm drive,
while the other four channels of a 5.1 configuration only
have 600 ohm drive. The 32 ohm drive is stronger than the
600 ohm drive, and the 600 ohm is only suitable for amplified
speakers. Even the 32 ohm is not that strong.

It could be that CMedia doesn't really want all the channels
to be using their 32 ohm drive at the same time, if it caused
the chip to get hot. Since you have the mixer control panel
in front of you, take a look and see if there are any
tick boxes in the interface, to enable 32 ohm drive on
more of the channels.

In any case, driving speakers directly is not going to work
that well, as you cannot squeeze a lot of power out of a
1Vrms signal into 32 ohm load. In the motherboard manuals
I've read so far, I've never seen a 2 watt amplifier added
to the sound subsystem, but I understand that it is done on
some computer products. Since the quality of such a solution
would suck, it is much better to connect computer sound to a
stereo or computer speaker system. And, for that matter,
any sound chips right on the motherboard, will have
an inferior noise floor, making it difficult to listen to
classical music with a wide dynamic range, without hearing
"mouse noises" in the backgrounds of quiet music passages.
That is where the Audigy or other PCI sound card comes in,
as they are better in that respect.

HTH,
Paul

"Paul" wrote in message
...
In article , "Martin Chatfield"
wrote:

Can I connect speakers to the gray (LS/RS) socket without an amplifier? I
have tried this and the sound is almost inaudible. The same speakers,
cables
etc. are fine when I use the green (L/R) socket.

Thanks
Martin

I downloaded the datasheet for the CMI9880 chip, and the
datasheet claims there is 32 ohm headphone drive available
on each port. What is unclear, is whether the software
will enable all of them at the same time, or has the
notion of only supporting that drive on one selected
pair of channels at a time.

In the "old days" of AC97, the stereo Lineout had 32 ohm drive,
while the other four channels of a 5.1 configuration only
have 600 ohm drive. The 32 ohm drive is stronger than the
600 ohm drive, and the 600 ohm is only suitable for amplified
speakers. Even the 32 ohm is not that strong.

It could be that CMedia doesn't really want all the channels
to be using their 32 ohm drive at the same time, if it caused
the chip to get hot. Since you have the mixer control panel
in front of you, take a look and see if there are any
tick boxes in the interface, to enable 32 ohm drive on
more of the channels.

In any case, driving speakers directly is not going to work
that well, as you cannot squeeze a lot of power out of a
1Vrms signal into 32 ohm load. In the motherboard manuals
I've read so far, I've never seen a 2 watt amplifier added
to the sound subsystem, but I understand that it is done on
some computer products. Since the quality of such a solution
would suck, it is much better to connect computer sound to a
stereo or computer speaker system. And, for that matter,
any sound chips right on the motherboard, will have
an inferior noise floor, making it difficult to listen to
classical music with a wide dynamic range, without hearing
"mouse noises" in the backgrounds of quiet music passages.
That is where the Audigy or other PCI sound card comes in,
as they are better in that respect.

HTH,
Paul

Thanks for that, I was just wondering why they bother to put all those jack
sockets on the motherboard if you need an external amplifier anyway. I have
a Creative DTT2500 speaker system but the spdif inputs have never worked (I
get stereo or nothing and I have never seen the Dolby light come on, this is
on 3 different systems), so I thought I would connect the speakers directly
to the jacks as an experiment. Time to get a new speaker system.

Thanks
Martin