Question about Amp Strength & Equalization.

[Mkilbride]

Alright so I recently picked up a Soundblaster G6 after looking around a ton. Mainly got this for playing on consoles which are a pain in the ass with headphones. After the recommendation from a friend, I decided to try the Harman Curve by Oratory. I have the Sennheiser HD600. Part of his recommendations are -11dB Pre-Amp gain.

So doing this, obviously things got a lot quieter on my G6. But strangely, it didn't really raise the volume when I moved the dial up, I mean it did, but only certain things got louder really, not everything. At least it felt that way, kind of mechanical, hollow. I don't know the proper audiophile term for this. So I grabbed my old Fiio A5, which has more power than my G6. (.111mw at 300Ohm vs .85mw at 300 ohm). I used it as the amp and the G6 as just the dac. It sounded like volume got marginally louder, but not significantly, and still it sounded a tad hollow. Which is wild, because without the EQ, without the SB6 and plugged into my AVR's lineout, the A5 can make my HD600 earblisteringly loud to the point of pain, on *low* gain. Which maxes out at .45mw. Of course that's with no pre-amp of -11.0dB. Yet even on High Gain like this, it can't get painfully loud and would sometimes pop.

Thing is even with the EQ disabled, it seems to still fail to get that loud. It's connected via Optical to my LG TV and my PS5 into my TV's HDMI port. I'm wondering if it's a PS5 thing? I'm using optical so I can get the Dolby Digital 5.1 track for VSS. Can't do that via USB.

Thinking this was a "more power" situation, I found a Topping L30 II Amp on sale for 100$ Open Box, still had the plastic seal wrap on it. Far better Amp than my other stuff I own, so it seemed like a fair bet to buy regardless. Using the Line out to connect to the topping, I plugged it in on low gain. I mean, it has .600mw at 300 Ohms. Far, far more power than my other devices. I remind you I'm not an audiophile, this is just what I thought the more power meant = more volume. So I turned it on and heard nothing at low gain, even with the volume 100%. Turning it to Medium gain and slowly rising I could hear it until I hit 100%, where it was almost at the right level, but sadly not quite yet. So I switched to High gain, and around the 3 o clock portion of the dial, I got to the just about perfect volume level. But at high gain...and this thing drives over 6x the power of my other Amp. Very shocking, I started with Low, knowing it was -12dB because I figured it'd barely sip at this thing, makes me realize I really don't know anything about all this.

The sound with the Topping L30 II however is no longer robotic or hollow, which honestly doesn't make sense here as it shouldn't affect audio quality at all, and generally the high gain on my A5 and the Q6 were around a similar position in the volume dial.

All in all, leaving me confused. Does not having so much more power, even with the easy to drive HD600, mean it'd get louder? Like I can fully high gain, 100% volume, and it hurts to listen to, but not like hearing damage instantly level, which is what I'd think so much power versus the others would do.

Or with a -11dB pre-amp gain is it normal to need so much more power? From what I read, every 10dB is like twice perceived loudness, but even with it off it's still not pushing anything insane.

 

[IAtaman]

I am not sure what exactly your question is so I will try to throw information at you in an effort to help clarify whatever it is that you find confusing

Very simply put an amp takes an input voltage, multiplies with its internal gain, and produces an output voltage. It tries to keep the output voltage inline with the voltage at its input no matter what is the load impedance. So for example, if you supply an amp with 2Vrms, and if it has a gain of 14dB, it would produce roughly 10V at its outputs. If it is driving a 300ohm headphone, it would need to deliver ca 300mW of power to do so, and if it is driving a 32ohm headphone it would be supplying 3.2W. If you supply the same amp with 0.5V, its output voltage would be 2.5V and can maximum produce ca 20mW with 300ohm load.

Coming back to your case, when you apply 11dB attenuation to your input signal, you are effectively cutting it by a 3rd. If your DAC was producing 1Vpp at its output terminals, now it is producing roughly 0.3Vpp or 0.2Vrms. Even if you have an amp that can deliver enough power to your headphone, if its gain is not high enough to produce enough output voltage to do so it will not be able to drive your headphones loud enough. To do the math, 0.2Vrms produces ca 0.1mW power at 100% volume at unity gain and according to its specs HD600 produces ca 85dB SPL at 0.2vRMS which is normal listening levels and aligns with your experience.

Hope this was useful.

 

[castleofargh]

A lot to unpack here.
First, I personally would not boost a HD600 by 10dB at 30Hz. You're going to add a lot of distortions (when listening loudly) while really not getting to hear much of the boost itself. If you enjoy more bass (which for gaming is a double edge sword, it pulls us in but only reduces our ability to locate things by ear), I would suggest boosting somewhere in the 50 to 80Hz area where we're more sensitive and most of the boom boom content is found. For the same amount, 80Hz is felt more, but then I personally dislike any boost above 100Hz, so I either have another EQ point to counter the 80Hz boost above 100Hz, or I just boost around 50Hz with a Q that goes down to almost zero near 100Hz. Anyway, that's entirely personal, do whatever you enjoy.

So, my main idea would be to end up with maybe between +3 and +6dB around 50Hz instead, so now you can afford to lower the main gain on the EQ to -6 instead of -11dB.

To be clear, I take that type of liberty because even if you or your friend is a hardcore fan of Harman target, there is an entire paper from Harman on that very project explaining how different people will prefer different amount of bass boost(most of it was apparently explained by differences in placement and seal quality). So Even Harman doesn't tell you to get stuck on the bass boost they suggest.


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Next, your screenshot shows no Q value for the filters, is it somewhere else or is it that you don't have the possibility of setting it? If you have no Q control and the creator of that EQ did, the odds are that what you're hearing is not what you're supposed to.
So maybe one aspect of the sound not feeling right is that it isn't?

Another possibility is simply that you in particular have a head that's not a good fit for the Harman target. The issue with statistical targets is that they're in fact not for everybody because we're not all clones of each other.

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G6. Amir measured it and if my very quick overview didn't fool me, the line out is distorting bad at full scale, and you'd seriously benefit from lowering the output by 2dB to avoid distortions.
Could it be that what feels wrong to you was that? Or the sum of all of the above? IDK.

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Power, well I don't know what's what for your other gears, but beside what @IAtaman explained, maybe a more straightforward reference for you would be +10dB requires 10 times the power.
Otherwise, sometimes gain is expressed as a multiplier of voltage, and sometimes the value is a dB increase. Obviously, we need to double-check that because one is linear and the other logarithmic, so the misunderstanding can become real big, real quick.
So this,

So I grabbed my old Fiio A5, which has more power than my G6. (.111mw at 300Ohm vs .85mw at 300 ohm). I used it as the amp and the G6 as just the dac. It sounded like volume got marginally louder, but not significantly, and still it sounded a tad hollow.

85 VS 111mw, if those are the correct amounts into 300ohm, marginal difference in loudness is normal(maybe a little over 1dB).

 

[tomb]

A few rules of thumb here:

• 3 dB is the quantity that approximates a Doubling in power. This is logarithmic based by 2, meaning that 6 dB is 4 times the power, and 9 dB is 8 times the power required. It just so happens that 10dB falls out at approximately 10 times the power, but adding 3dB to that (13dB) results in 20 times the power! (And so on to infinity ...)
• Used incorrectly, equalizers can easily blow out an amplifier or speaker. This is probably the reason for the -11dB overall gain adjustment prior to adjusting gain on the individual frequencies. As you can see by the first point above, increasing dB at specific frequencies can sometimes present a brick wall to an amplifier.
• Yes, the HD580/600/650 family is easy to drive ... with voltage. If you're applying a typical battery-powered, portable, solid-state amp, it will struggle to provide sufficient voltage swing at 300 ohms.