SoundMAX Digital Audio

[lmaes]

Hi all,

We tried to install DRM Software Radio on a different laptop that has a SoundMAX Digital Audio soundcard.

After plugging the mini jack into the mic socket, all we get is the following on our screen.

Anyone has an idea how I can solve the problem?

Ludo

[simone]

Hi Ludo,
can you send a screenshot from DReaM showing the input spectrum?
Btw I also have a problem with this kind of soundcard, but that´s different.
Simone

[carknue]

Hi Ludo,

looks like the noise reduction function is enabled for the mic in. I also have Soundmax Chip in one of my PCs and can remember your screenshot. I think that you can disable the noise reduction only in the soundmax software and not in the windows control, but I'm not sure. The noise reduction cuts all high frequencies that are not needed for speech.

[mitajohn]

Hi all,

Yes, you MUST disable NR for the mic input from the soundmax settings panel and the mic gain boost also on Windows recording control!

John

[lmaes]

Hi Simone, Carsten and John,

Thanks for the advice. I have disabled the noise reduction and that gives the following screen.

However, no audio yet and max SNR of about 6.

It seems the signal is not low enough +/- 4.5 kHz.

Any ideas?

Ludo

[simone]

Hi Ludo,
looks like the input level is much too high, is the mic booster on that needs to be switched off?
Or just enable and disable the mic input a few times and move the slider for the input level, sometimes the behaviour is quite strange.
Simone

[carknue]

Hi Ludo,

now you need to disable Mic boost or mic AGC or +20db or whatever this feature is mostly in the windows rec sound settings and lower the input level. See attached screenshot

[carknue]

Hi Ludo,

the signal looks ok, but the input level is much too high. You should try to lower the record input level from mic or line input in windows control system. Maybe there is a software switch where you can change the inpupt type from mic to line, because notebooks usually have only one input conector for line and mic. And disable any mic boost,+20db boost or agc features.

You can send me screenshots from your sound settings and i will take a look.

[simone]

Hi Ludo,
we have the same sound card on our notebook, even with the mic slider close to zero the input level is a bit high, I think with your reeciver you have to solve it by hardware.
Simone

[carknue]

Ludo, try to install a different sound driver for your sound chip. If there are special sound software and drivers from your notebook manufractor, deinstall them and try windows standard drivers. Or download drivers direcly from soundmax or your notebook manufractor.

Does your Soundmax driver have the red marked feature? If not, it is enabled by default and you need another driver, where you can disable this feature.

[simone]

Hi Ludo,
I don´t think it will work with the standard Windows driver, use the soundmax audiomanager, there is an option where it adjusts the microphone input level automatically (you will be asked to count from 1- 10), this helped as lot, if it is still too high, try a hardware solution (resistor).
Simone

[FritzWue]

Same audio level problem with the DRT1 and a DELL Latitude here.
I solved it by using an attenuator cable with 10k Ohm in series in the DRT1 output plug and 200 Ohm in parallel in the notebook input plug.
I also have to run the notebook on batteries. As soon as I use any kind of power supply there is too much noise at the soundcard input.
Probably this noise is coming from the electronic circuitry in the battery pack itself.

[lmaes]

Hi Carsten, Simone and Fritz,

Thanks so much for your ideas and proposals. Enclosed is a screenshot of both incoming and recording mic level with the mic boost option disabled. Also, the picture was taken with the laptop on battery power, no mains connected.

It seems not possible to change from mic to line input level, at least we did not find it yet on the laptop.

Is there perhaps a possibility to attenuate the level coming out of the AOR 7030?

Ludo

[simone]

Hi Ludo,
I would not reduce the level at the output of t he AOR, better make yourself a special cable (with resitors in the plugs) so you can still use the AOR with the line in of a normal PC alternatively, that´s what I meant with hardware solution in my post yesterday.
Simone

[DG9BFC]

hello drm friends
i have also a soundmax in my notebook MEDION 9788 .... without ANY problems BUT i modified the notebook because i had some background noise ....
it came from the brigthness control of the display-backlight ....
i had a 200hz hum in mic and also in line out ... very bad if you hear music over your hifi equipment :-(
i opened the display and located the connector to the motherboard...
there was 1 pin with an analog voltage from 1-2 volts
1 volt max backlight and a little hum
2 volts min backlight and also hum ....
i could see the signal of the inverter when i had the probe of the oscilloscope near the inverter....
it is a 100khz signal with a 200hz pwm ....
so how get a solution??
i just cut the pin with the analog signal and my display now runs with full brightness for almost 3 years now ....
the hum is totally gone!!!
now every digital mode over shortwave (like rtty, psk and so on)
and also drm reception works superb
my record is 40.6 db with my icom trx and a mixerboard

[dk8cb]

... and my display now runs with full brightness for almost 3 years now ....

... but at full power consumption of the display background lighting which will drain the battery more quickly and probably also shorten the life of the backlight tubes.

Proper screening and grounding of the LCD backlight control and power wires or perhaps - if everything else fails - using an external USB sound adapter might be a better idea.

Roland

[DG9BFC]

... but at full power consumption of the display background lighting which will drain the battery more quickly and probably also shorten the life of the backlight tubes.

Proper screening and grounding of the LCD backlight control and power wires or perhaps - if everything else fails - using an external USB sound adapter might be a better idea.

Roland

battery life is no problem .... and the tubes doesnt run much brighter than before ... so life of the tubes is also no problem ....
the pwm signal was on the 5v rail ... because of the different current
when the backlight is switched on and off from the pwm signal....
and the onboard sound gets its power from the 5v rail too .....
connecting a capacitor didn´t help .... okay maybe a external soundcard would help but i had none .... so i searched for another solution
and my solution works now for about 3-4 years ! ! !
this should only be a little tip for others with the same hum noise....

greetz
sigi