Gazdatronik
Super Member
AKA...What is this noise I'm hearing?
I have been worried lately about gain staging and modern computer soundcards, and changes in way things are.
I have long known that some newer computer soundcards use a new standard of volume control. 100% used to be a fairly consistent reference voltage that worked fine on auxiliary inputs. But these days, the cheap soundcards change their output digitally as it eliminates(for cost reasons) the "need" for a analog output amplifier that can change via computer control, the speaker icon/slider on the taskbar. Nowadays, I find 50% to be the old 100%, and anything over 50% is digitally boosted by manipulating the 1's and 0's, SQ be damned, at least it is "louder."
My friend got a pair of Klipsch Sixes, which have an internal DAC, as his computer speakers, and told me via text that after he hooked the digital input up, it was much better, that the analog feed from his computer sounded quite bad. I am of the persuasion that while DACs vary, they should only vary based on output stages, and that variance should not be so markedly different across brands to be unpleasant unless something is very wrong.
I didn't get to pay him a visit until yesterday, and we worked on that problem. At first, I couldn't hear a difference, but my source material didn't have a whole lot of treble. So I went to my old standard, https://www.szynalski.com/tone-generator/ to test the sweep and his sub crossover point. Not the best Tone Generator, but enough to show a serious flaw.
Back to my friend's setup-
So as I slide the frequency slider up and down past 15khz, all hell breaks loose and nasty shortwave-sounding artifacts start coming through his speakers. The digital feed from his computer through the same speakers sounded perefct above 15khz, only the analog input seems to have the issue.
So I reduce the analog volume to about 68% (which is 0.5v reference on my newer Dell) and run the sweep up again. The foldback artifacts are still there. I reduce the volume to 50%. The issue disappears. Not only that, the digital and analog input gain now match. He had written a script that could change the speaker inputs and computer outputs on the fly so we were able to A/B it more effectively. Everything now sounds as it should.
I knew this exact test could be used on my own computer as I was not sure what sort of volume control my newer Dell used, there was no documentation on the onboard chipset. So I ran the frequency sweep again at full volume and sure enough, my soundcard had identical distortion. Only difference was my artifacts went away at 68% volume. Whether that has to do with the 0.5v reference previously established, I have no idea, but at least I know what I am working with.
My OLD Dell I still use for music production, a 2002 Optiplex 260 with a bog standard Creative Soundblaster PCI128 and analog buffers had no issues at all with any of the above tests, whether or not the volume was maxed out. This was something we didn't have to worry about as much 20 years ago I suppose.
As I read this sometimes I think its just worth it to buy an outboard DAC just so you don't have to worry if the thing is set right or not. However, it is nice to figure out why some computers sound fine, and some don't. Its even nicer to find out it can be easily fixed by reducing the output volume.
I have been worried lately about gain staging and modern computer soundcards, and changes in way things are.
I have long known that some newer computer soundcards use a new standard of volume control. 100% used to be a fairly consistent reference voltage that worked fine on auxiliary inputs. But these days, the cheap soundcards change their output digitally as it eliminates(for cost reasons) the "need" for a analog output amplifier that can change via computer control, the speaker icon/slider on the taskbar. Nowadays, I find 50% to be the old 100%, and anything over 50% is digitally boosted by manipulating the 1's and 0's, SQ be damned, at least it is "louder."
My friend got a pair of Klipsch Sixes, which have an internal DAC, as his computer speakers, and told me via text that after he hooked the digital input up, it was much better, that the analog feed from his computer sounded quite bad. I am of the persuasion that while DACs vary, they should only vary based on output stages, and that variance should not be so markedly different across brands to be unpleasant unless something is very wrong.
I didn't get to pay him a visit until yesterday, and we worked on that problem. At first, I couldn't hear a difference, but my source material didn't have a whole lot of treble. So I went to my old standard, https://www.szynalski.com/tone-generator/ to test the sweep and his sub crossover point. Not the best Tone Generator, but enough to show a serious flaw.
Back to my friend's setup-
So as I slide the frequency slider up and down past 15khz, all hell breaks loose and nasty shortwave-sounding artifacts start coming through his speakers. The digital feed from his computer through the same speakers sounded perefct above 15khz, only the analog input seems to have the issue.
So I reduce the analog volume to about 68% (which is 0.5v reference on my newer Dell) and run the sweep up again. The foldback artifacts are still there. I reduce the volume to 50%. The issue disappears. Not only that, the digital and analog input gain now match. He had written a script that could change the speaker inputs and computer outputs on the fly so we were able to A/B it more effectively. Everything now sounds as it should.
I knew this exact test could be used on my own computer as I was not sure what sort of volume control my newer Dell used, there was no documentation on the onboard chipset. So I ran the frequency sweep again at full volume and sure enough, my soundcard had identical distortion. Only difference was my artifacts went away at 68% volume. Whether that has to do with the 0.5v reference previously established, I have no idea, but at least I know what I am working with.
My OLD Dell I still use for music production, a 2002 Optiplex 260 with a bog standard Creative Soundblaster PCI128 and analog buffers had no issues at all with any of the above tests, whether or not the volume was maxed out. This was something we didn't have to worry about as much 20 years ago I suppose.
As I read this sometimes I think its just worth it to buy an outboard DAC just so you don't have to worry if the thing is set right or not. However, it is nice to figure out why some computers sound fine, and some don't. Its even nicer to find out it can be easily fixed by reducing the output volume.