6 replies to this topic

[Iceman_jkh]

Hey all,

Just been looking at some specs for my intended CarPC.. and I came to the specs of the PXAH701.

Question is:
Is there any point in getting a soundcard that has a SNR = 140dB when the PXA only has SNR of about 100dB?

Sounds cards with such high SNR get exponentially more expensive, thats why this could be a good place to save money, if its not going to add much to SQ

I'll be using the Toslink output on the card into the PXA, but I couldnt find any 'detailed' PXA specs about the digital vs. analogue SQ.

I might as well just get a cheaper card that has a SNR = 100dB aswell. In saying that... should ALL the gear I get have similar SNR's as that of my amps - cause ultimately they will also limit the system (if my thinking is correct).

Just curious for some opinions.
Thanx

Edited by Iceman_jkh, 02 October 2005 - 10:39 AM.

[gooki]

Quote

Is there any point in getting a soundcard that has a SNR = 140dB when the PXA only has SNR of about 100dB?

No

[MADTRAV]

PXA H701 gets my vote, much simpler to obtain/fit/wire. relatively inexpensive for what it can do

[Iceman_jkh]

I mean.. using a soundcard with a SNR of 140, to feed into a PXAH701 (which has an SNR of 100) to control EQ/TA/etc...

Does the SNR of the PXA bring the entire system SNR down to 100dB anyway....

If it does, I should just get a soundcard with a SNR = 100 not 140.

[Ascension24]

The SNR refers to the analog output of the card, not the digital (i am pretty sure, but get a second opinion)

So having a two cards with different specs doesnt really matter if your going to be using digital out, because the digital out is a digital signal, will be the same no matter which card you use. (the card just gives a plug with digital, doesnt do anything to the signal)

Check if you can buy an adapter for your motherboard for a digital plug, but if you cant then then just get any card with digital out.

And also, the differnece between 100 and 140 SNR is no big deal, and anyone here will also tell you the SNR is really no measurement of the actualy quality of the sound, something with a 140 SNR could still sound ALOT worse then something with a 90 SNR. Its a measurement of how much noise is introduced into the processed sound, you could have no noise introduced to the processed sound, but if the sound is processed craply (cheap DAC) then its still going to sound bad.

Edited by Ascension24, 02 October 2005 - 03:35 PM.

[Dogo]

definitely use the digital from carpc to pxa, theres no need to add an extra layer of DAC in there.

You might find the carpc has worse specs in a car than on a desk due to the unstable 12v power supply

[Iceman_jkh]

Yes, i agree that using a digital output is a good idea if possible.

It 'protects' the sound stream from electrical noise induced by the sound card DAC's, the cars electrical system, cable runs... etc.

So I was just curious if having such a high SNR is worthwhile, as the item with the lowest SNR in the system (HU, CarPC, Amps, processor) will ultimately determine the overall maximum SNR of the system...

Having said that, I think I can save myself some money in some areas, and still get good sound as long as I look for a card that gives good (low) THD, (high) Dynamic range and (high) Channel Crosstalk rejection figures.

Basically, I just want to ensure I'm matching my devices as best as possible (without any overkill)... no point putting F1 status HU with Dicksmith 4" coaxials .

Ascension> I believe the SNR is a function of "the re-construction of sound data by the processing device", not a function of the transport medium. The medium may determine how much additional noise is induced/rejected during transport to another device (ie: from the cabling). Also additional noise is added during conversion from D to A - This is why the analogue outs "should" have a worse SNR.

So I dont think that just because something has digital out, thats means its 'got' to be good, it might just be 'better' than the analogue signal from the same chipset.

The Digital Out should have its own SNR, which should hopefully be higher than the analogue output, due to not having to go through another set of processors/converters.

(as can be seen in some www.digit-life.com reviews).

Edited by Iceman_jkh, 03 October 2005 - 04:41 PM.