DVC and Preamp Gain

[Serendipity]

Hello, PA community.

I'm applying heavy EQ to my bluetooth headphones with a large negative preamp gain (~ -7dB) following Jaakko Pasanen's AutoEq settings list.

My inquiry: If I have DVC enabled, Can I increase the preamp gain (making it less negative) while still preventing any audio clipping and maintaining audio quality, or does it not work that way?

I'm asking this because some of the older tracks I have require that I max out both phone and BT device volumes (with Absolute Volume Disabled) to get to enjoyable levels of listening with the preamp setting I have, and I'm not too fond of having to adjust the volume many times through a session.

Thank you!

[MotleyG]

The -7dB preamp isn't an excessive amount of negative gain, especially if the equalization you are applying has several bands that have been boosted by an equal amount or more. This isn't the same as idea DVC, but they can be used in combination if your device supports it. However with Bluetooth devices, including headphones, usually DVC is not available. But there are an incredible number of potential mixes of mobile devices and connected speakers/headphones/dongles/DACs. You will need to determine this yourself for your combination and tuning preferences.

[Serendipity]

Thank you for the reply, @MotleyG 

So, I get that I probably shouldn't increase the preamp gain or I may run into clipping issues as you've said DVC is not related, so I'm assuming it's not giving me extra headroom, right?

Also, DVC with BT does actually work with my device and I prefer it enabled. It's actually only some of the older tracks from the 70s and 80s that I'm finding quieter than I prefer. But I think that's probably more an issue of their older mastering than anything else it seems.

[MotleyG]

55 minutes ago, Serendipity said:

It's actually only some of the older tracks from the 70s and 80s that I'm finding quieter than I prefer. But I think that's probably more an issue of their older mastering than anything else it seems.

You can use Replaygain to adjust for this. You will need an external app (usually on a desktop rather than a mobile) to analyze your files and add the tag data. But once you have this, you can tell Poweramp to use it to automatically balance the levels between tracks at the Album or Track level.

[andrewilley]

ReplayGain is a useful tool if the digital file you are dealing with has been encoded at a particularly low level, but it's not a very clever system in that it only tracks and adjusts based on the single peak moment in any given track. So one very loud drumbeat in an otherwise quiet song could fool it. Also, there's a lot more to how 'loud' a recording is perceived by the ear than just its technical volume level, some recordings have much wider dynamic range than others for example, and there may have been some compression introduced in the studio mastering process. But it's a good start at least.

DVC generally does provides more headroom, but it's still not a good idea to be pushing beyond 100% digital anywhere in the audio chain.

Andre

[Sean Garette Gajitos]

I'm still a bit confused. When doing PEQ adjustments, do I still need to put the appropriate preamp levels even when DVC is on? Thanks!

[andrewilley]

@Sean Garette Gajitos There is no "appropriate" preamp level, it's just a volume control. But if you set it too high, and then you also ramp up even more volume in some bands using the EQ sliders, you could introduce distortion and clipping at peak moments in your music by pushing the signal beyond 100%. DVC does help by offering greater headroom though.

Andre

[Sean Garette Gajitos]

 

14 minutes ago, andrewilley said:

@Sean Garette Gajitos There is no "appropriate" preamp level

So if let's say I have a 6db boost in a certain frequency, I can let DVC handle it? Thanks again!

[MotleyG]

9 hours ago, Sean Garette Gajitos said:

 

So if let's say I have a 6db boost in a certain frequency, I can let DVC handle it? Thanks again!

You can try it and see if you have any noticeable distortion. It would depend on how high the levels are in the file itself, if you have Replaygain enabled, and the hardware capabilities of your devices DAC and headphone amplifier (if this applies).

In my personal experience, it is ideal to lower the preamp by an amount equal to the highest EQ boost applied. This will ensure that nothing should exceed the digital maximimum, again assuming the file itself doesn’t already have clipping. 

[Sean Garette Gajitos]

I see. The headphones I'm using maxes out my phone's volume when using EQ with preamp

8 minutes ago, MotleyG said:

In my personal experience, it is ideal to lower the preamp by an amount equal to the highest EQ boost applied. 

Yes this is what I was referring to. I was hoping that I can ditch the preamp and just have DVC so I can have a bit higher volume available (and avoid the annoying volume change when using other apps, destroys my ears). I'll try it out and see if I notice any distortion, thanks.

[andrewilley]

Volume for volume's sake is never a good way to go unless you're at a Heavy Metal concert. Like car speedometers, just because the knob goes up to 11 doesn't mean that's what you should aim for. However I do see your logic with wanting all of your apps to output at similar levels. If you over-boost the gain you will not experience problems most of the time, but if you encounter a peak-level segment in a recording, and then try to boost it beyond that 100% digital level, there is nothing to do but clip the peaks. If you enable the Limiter then such over-level peak sections will be attenuated rather than clipped, so that's one way to audibly detect if it happens.

Internally PA uses 32/64-bit processing, so should have plenty of headroom for whatever you throw at it, but sooner or later the signal path has to get back into the normal world.

Andre 

[hypomaniac-eric]

On 10/21/2022 at 3:47 PM, MotleyG said:

You can use Replaygain to adjust for this. You will need an external app (usually on a desktop rather than a mobile) to analyze your files and add the tag data. But once you have this, you can tell Poweramp to use it to automatically balance the levels between tracks at the Album or Track level.

I use MP3Gain since the early 00's.  works good most the time.  sometimes i have to manually tweak some songs with it with a diff setting.