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Practical (audible) implications between lower SINAD and heavy EQ with massive negative pre-gains

Merkurio

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Hi there! It’s me and my long-ass titles again.

I've had this question on my mind for a while, when I decided to use the Qudelix-5K not only as a BT dongle, but as a solution for all my needs (including desktop DAC) thanks to their DSP capabilities.

As some may know, the SINAD of the Qudelix-5K it's around 80-85 dB, nothing special but fine for their intended portable use, I suppose.

The problem comes when it's time to equalize and apply large negative pre-gain values to avoid clipping, just like in the case of the HD660S I bought a couple of days ago, I need exactly -14.5 dB of pre-gain to avoid clipping in the sub-bass region. Amir states in this post that a lower SINAD to begin with could be detrimental at an audible level after applying this type of aggressive EQ, to the point of being able to lose sound information within the 16-bit range.

I don't have any problem with the sound of the Qudelix, especially after equalizing, it's just a matter of peace of mind and knowing if I can improve my audio chain a bit, since I haven't had a DAC with SINAD higher than 100 dB for a long time to do a proper blind test and compare for myself.

Can someone elaborate more on this?
 
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AnalogSteph

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Does it still go loud enough? If so, the remaining dynamic range is obviously fine for your uses. (The Qudelix-5K manages about 110 dB unbalanced and 120 dB balanced.)

Now what about the distortion part? It is actually rare for half-decent electronics to generate enough IMD to become a problem. There also generally isn't an awful lot of signal in the subbass where most of your boost is. Also, the HD660S is likely to have much greater issues with this, open dynamic cans just have their limits down there...

If you want to be absolutely sure that the Qudelix-5K is not a problem, you could still invest in a balanced cable for the HD660S to use with the 2.5 mm output. With 6 dB more output and 4 dB lower noise floor, that's basically a no-brainer.

As an aside, if you already have ReplayGain or other volume normalization in action, you can probably trade off pre-gain there against EQ pre-gain to some degree and find a total attenuation that both keeps you out of clipping and still maintains a decent digital level. You may want to temporarily model the Qudelix PEQ on the PC (e.g. with Equalizer APO + PEACE) so you get a decent idea of actual digital peak levels encountered.
 
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Merkurio

Merkurio

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Does it still go loud enough? If so, the remaining dynamic range is obviously fine for your uses. (The Qudelix-5K manages about 110 dB unbalanced and 120 dB balanced.)

Now what about the distortion part? It is actually rare for half-decent electronics to generate enough IMD to become a problem. There also generally isn't an awful lot of signal in the subbass where most of your boost is. Also, the HD660S is likely to have much greater issues with this, open dynamic cans just have their limits down there...

If you want to be absolutely sure that the Qudelix-5K is not a problem, you could still invest in a balanced cable for the HD660S to use with the 2.5 mm output. With 6 dB more output and 4 dB lower noise floor, that's basically a no-brainer.

As an aside, if you already have ReplayGain or other volume normalization in action, you can probably trade off pre-gain there against EQ pre-gain to some degree and find a total attenuation that both keeps you out of clipping and still maintains a decent digital level. You may want to temporarily model the Qudelix PEQ on the PC (e.g. with Equalizer APO + PEACE) so you get a decent idea of actual digital peak levels encountered.

Thank you very much for the comprehensive response and an apology for the delay in responding so far, I've had a busy few weeks.

Indeed, I tried volume leveling with Roon (using ReplayGain) and was able to find the right balance between both pre-gains as you said, with satisfactory results, resorting in only -6 dB on the EQ pre-gain side for the HD660s. :)

However, I've been back to using IEMs lately and my amplification needs post-EQ haven't been nearly as saturated as with the HD660s, but anyway, thanks for the insight!
 
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