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Line Level Attenuation and Volume Dial position - Discussion

I've just been looking up how to understand decibels in electrical engineering terms, because that's the last main thing left on this topic that I'm still unclear on, that I know of at least.
Anyway, I came across one of Dave's EEVblog videos and true to form, barely a minute in, Dave made me chuckle with one of his random comments, so here is the video in case anyone comes across this later and needs to understand decibels too.
 
Right, I think I understand how to calculate db reduction now.
So the formula is, (when converting voltage reduction to db reduction):
db = 20 * log(v1/v2)
so in my case, (based on the 12k, 1k scenario, (or 6k, 500 ohms):
v1 - 154mv (resulting voltage drop at input of receiver aux rca connectors)
v2 = 2v or 2000mv, (from cd player)
v1/ v2 = 0.077
log(0.077) = -1.113
20 * -1.113 = -22.26 db
So if I've understood correctly and if my math is correct, by attenuating the 2v from the cd player, down to 154mv, I'm creating a 22.26 decibel drop.

And now armed with that new found knowledge, I'm off to bed, lol. Night.
 
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I always try to set input levels so that my listening level is between 10 and 2 on the volume control. This seems to give me the best compromise between in room volume and adjustability. IME between 10 and 2 volume controls have better channel balance and seem to be more responsive to small and large level changes.
 
JoeESP9 said:
I always try to set input levels so that my listening level is between 10 and 2 on the volume control. This seems to give me the best compromise between in room volume and adjustability. IME between 10 and 2 volume controls have better channel balance and seem to be more responsive to small and large level changes.
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Thanks for your input @JoeESP9. Using the resistor combination that I mentioned above, 12k and 1k, it would seem that is the area of the volume control that I've ended up at too, although I can actually turn it all of the way around to the 3pm position and although it's loud, it still isn't uncomfortable to listen to. This may make you laugh, but I'm actually really nervous turning the volume control that far around. I mean, I know that by design, the receiver shouldn't have a problem with it, or the designers wouldn't have allowed, (correct speaker ratings aside that is), but I've never needed to go beyond the 11 o'clock position on anything before and the one and only time I did that, it was in my teens and I blew an internal fuse on the all in one system I was using at the time.

I agree that it's giving me far greater control to make tiny volume adjustments, because I'm having to turn the control much further to affect the same amount of volume change compared to previously. I'm actually wondering though if I might have just given it slightly too much attenuation. I mean, the mv are about what I expected them to be and that is what the aux input on my receiver is rated at, but I'm wondering if that's a nominal rating, rather than an absolute requirement? If I have it as it is now, my Turntable is going to be a lot louder than my cd player and I'd like all of my inputs to be roughly the same level, so I don't switch between them and get jump scared when the one I've switched to is much louder.

The more difficult one to work out what to do with is going to be my DAC. That is supposedly also rated at 2v out, but because it's coming from my PC and because I use a volume control that's built into my keyboard, the DAC won't be outputting a voltage value that is knowable in advance and I like to have the receiver volume set so that the computer volume is generally at around 60%, to give some headroom to turn it up via the keyboard volume control if I need to.

Edit: I momentarily forgot that I'll be connecting my turntable via my if Zen phono, not directly into the receivers built in phono stage, so I guess I'll just need to attenuate that also, to ensure it's roughly the same volume as the cd player. Therefore it's just the DAC that's going to be more of a pain.
 
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Whatever application on the PC you're using to drive the DAC should have a level control. All the ones I'm aware of do.

I use Music Bee for pop/rock/jazz and AIMP for classical and opera. I've also tried Foobar, JRiver (Jukebox), Win Amp, Tune Browser, VLC and Media Monkey. They all have a volume control.

I leave the level control on my apps at maximum. My DAC has remote analog volume control. No bit dropping done.
 
JoeESP9 said:
Whatever application on the PC you're using to drive the DAC should have a level control. All the ones I'm aware of do.

I use Music Bee for pop/rock/jazz and AIMP for classical and opera. I've also tried Foobar, JRiver (Jukebox), Win Amp, Tune Browser, VLC and Media Monkey. They all have a volume control.

I leave the level control on my apps at maximum. My DAC has remote analog volume control. No bit dropping done.
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Actually, yes, I agree that the DAC has a level control. I just didn't explain very well. When I'm using the DAC as the output device from my PC, the volume control on my keyboard, controls the DAC output level. Using the same cable that I made for my cd player though, my DAC has almost no volume at all, even with the output level turned up all the way. I think though that is possibly because my DAC, which is a Topping D10 currently, has an output impedance of 100 ohms, compared to the (I think) 800 ohms of my cd player. If so, I'm thinking that a different resistor combination, to get the load that the DAC will see, down to around 1k, instead of almost 13k. For that matter, I could probably tweak the resistor values in the cable I've already made, to help my cd player out a little. Make that closer to 8k, instead of almost 13k. Unless I've misunderstood how that works.
 
That's because in your first configuration the PC is controlling the level going to the DAC.

FWIW: I have a Topping D-10. It's in my bedroom system. It drives a Little Dot MKII and a pair of HiFi Man HE-4xx. To prevent a digital volume control from reducing the bit depth, I keep the level on my music player at max. I use the volume control on the Little Dot for all level adjustments.

What player are you using? IIRC many of them install with the volume control set at 50%.
 
JoeESP9 said:
That's because in your first configuration the PC is controlling the level going to the DAC.

FWIW: I have a Topping D-10. It's in my bedroom system. It drives a Little Dot MKII and a pair of HiFi Man HE-4xx. To prevent a digital volume control from reducing the bit depth, I keep the level on my music player at max. I use the volume control on the Little Dot for all level adjustments.

What player are you using? IIRC many of them install with the volume control set at 50%.
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I've got a few different music players, but the one I use the most if Music Bee. The volume on that is set to max though. However, even with the Topping D10 volume set to max, (via the Windows control), it's still really quiet when connected via the attenuated cable, unless I turn the amplifier volume to around the 3 o'clock position. With normal cables it gets loud by the 9 o'clock position and stupidly loud and distorted by the 10 o'clock position, which is why I'm making attenuated cables. Both it and my cd player, output 2v, but the difference is that the cd player has a load impedance of 800 ohms and the D10 only has an output of 100 ohms. I can only assume that is why the sound level is quieter with the same 13k load. It's only a guess though.
 
Try using the volume control in Music Bee.

Also, turn off the resampling that Windows does automatically. Use the Windows sound control panel do it. Then make sure Music Bee is setup properly. You want it set for WASAPI in exclusive mode. You also want it set to not resample anything but play it as it is.

Using WASAPI bypasses the Windows mixer. It's known for reducing the sound quality. You could also use ASIO. It was written for Win7,
 
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JoeESP9 said:
Try using the volume control in Music Bee.

Also, turn off the resampling that Windows does automatically. Use the Windows sound control panel do it. Then make sure Music Bee is setup properly. You want it set for WASAPI in exclusive mode. You also want it set to not resample anything but play it as it is.

Using WASAPI bypasses the Windows mixer. It's known for reducing the sound quality. You could also use ASIO. It was written for Win7,
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Okay, thanks, I didn't know that and will give it a try. When I'm using my PC for audio, actually I mostly watch and listen to stuff online through youtube, netflix, amazon and disney plus. I do sometimes use Music Bee, but most of the time, if I want listen to music, it's on cd, tape or vinyl.
I've remade my diy attenuator to have 1.2k and 100 ohm resistors for the divider now, instead of 12k and 1k and it's definitely improved the volume level through the DAC. Currently the receiver volume is set to the 11 o'clock position and the PC volume is at 100% and is just about at my normal listening volume. The only caveat is that normally I'd have the PC volume set at 60% so that I can easily turn it up with the keyboard volume control, on quieter stuff and down for louder stuff. Currently I can't do that and would have to adjust it via the receiver, which is not what I want to do, especially for watching movies etc. Anyway, I'll have a play and see if I can improve it.
 
@JoeESP9, you're suggestions regarding WASAPI exclusive mode when using Music Bee, has definitely made a noticeable improvement on the sound quality when playing music through Music Bee. It's a shame those music files are all mp3 will never be high quality to begin with, but even so there's a difference.

Shame I can't get everything else to sound better. I've tried a few variations of attenuator, but I can definitely say with 100% certainty that when attenuating enough to allow the volume control on my receiver to be set to the 11 o'clock position, without bursting my ear-drums, the signal definitely loses resolution. At that point, everything sounds veiled and the sound stage disappears up its own backside. Without attenuation, the receiver is incredibly shouty, but really clear, unless it's turned up to above the 9 o'clock position.

I'm actually starting to think there just isn't a solution for it, which after spending so much time, effort and money restoring it, really sucks.
 
PJuddery said:
I've got a few different music players, but the one I use the most if Music Bee. The volume on that is set to max though. However, even with the Topping D10 volume set to max, (via the Windows control), it's still really quiet when connected via the attenuated cable, unless I turn the amplifier volume to around the 3 o'clock position. With normal cables it gets loud by the 9 o'clock position and stupidly loud and distorted by the 10 o'clock position, which is why I'm making attenuated cables. Both it and my cd player, output 2v, but the difference is that the cd player has a load impedance of 800 ohms and the D10 only has an output of 100 ohms. I can only assume that is why the sound level is quieter with the same 13k load. It's only a guess though.
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Wow - just no.
 
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