Originally Posted by nonsupremous
Ya, even with the Denon AH D2000 will clip if the precut is on 0db and you REALLY crank the bass. I tried my PK2's and it no clipping a little bass boost made mince meat out of them. The Earpods can handle much more low end.
Clipping is a digital effect. It has nothing to do with the headphones. If you take a signal thats already at max and try to digitally increase it, you get clipping. Doesn't matter if you have headphones, an amp, or a toaster hooked up. The signal will clip.
Thats what precut is for in an EQ, it lets you lower the overall gain enough that you have headroom to pump up certain frequency bands. So if you want to add +3dB more bass, you must apply some precut (the exact amount is harder to calculate, but -3dB is a good estimate).
Originally Posted by nicholars
Sorry but whilst the clip+ is a good little DAP it is not exactly a powerhouse and saying that any lack of bass is the headphones and not the DAP is... well wrong..
This is a common misconception. The amount of power a device can deliver into a given load actually does not in general say anything about how much bass it can drive. To understand why, you need to know a little bit more about how an EQ and a headphone amp actually work.
First, the EQ. Basically the combination of EQ + precut results in the selective attenuation of some frequencies relative to others. Since you're adding at least enough precut to cancel out any gain, your EQ on average makes the signal a little more quiet. So an EQ that "boosts" the bass frequencies actually leaves them more or less alone but cuts mids and higher frequencies. The overall sound is then a little quieter, but you can compensate for this by just raising the volume (that is, applying analog gain to compensate for the digital attenuation - its analog so no clipping).
So once you realize that an EQ is basically just attenuating some frequencies, you can see where power comes into play: it determines the maximum volume you can use from the amp. In rockbox we try to make this clear by expressing volume in units of dB relative to peak. So if you're listening at -10dB, you're listening at 10% of the amp's max power. At -20 dB, you are at 1% of the amp's max. So if you listen at -10dB in rockbox, and want to apply 4 dB of bass gain, you would precut -4dB (very roughly) and then raise the volume to -6dB. The end result is that your bass is now 4dB louder then it was before, while your mids and highs haven't changed at all. Thats the magic of a parametric EQ.
Of course, there is a downside: you're now 4dB closer to the maximum volume level. However in practice this isn't a huge issue, particularly with IEMs because you rarely use much of the amp's power due to how efficient they are.
Originally Posted by nicholars
Every pair of headphones / IEM I have ever owned has sounded bass light on the Clip compared to a proper amp.
Not a problem. The clip is a directly coupled, low impedance amp with very zero low frequency roll off or distortion. This is precisely the scenario where an EQ will fix your problem, just be sure to use it correctly.