HD600: My custom bass extension curves.

- EDIT: Curve Impulse Responses for convolvers now available (eg. Foobar2000 with Impulse Response Convolver plugin) - see below.

I got new HD600s a few days ago. I want them for mixing, so I ran my reference track on them (]The Cure - Open, from the Wish album) - it's super dense but also has rich low bass guitar.

I was struck how the lowest bass notes on that track roll off - not a disaster for listening, but not good for mixing. All the HD600 measurement curves show bass rolloff.

The pro-audio Sonarworks plugin (for VST/RTAS/AAX formats, 21 day trial available) has HD600 correction, and sure enough it corrects for some of the bass rolloff - but it also sounds weird to me elsewhere (at least on my setup & cans) so I started on my own curves, using Voxeng's GlissEQ plugin (free trial available). I found I can recover very low bass without bloating or faking - now my cans sound amazing, more enjoyable + closer to my studio monitors with sub, and much better for mixing (for me).

This is what Sonarworks does at the low end (in Mixed filter mode) - blue is the raw cans (note the bass rolloff), green curve is the correction:




My curves are mainly bass extensions, approximating that correction as a starting point (and then going lower). The thinking is that middle and treble are likely to vary more between cans, and anyway many pros consider the HD600 'reference' as they are. I did add a tiny treble slope to reveal a bit more detail, the Senn house-sound is a touch too laid-back to me (at least on my setup) - if you don't want that just zero the gain of the 10.1k node.

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Download the curves in GlissEQ preset format (the plugin can also export to CSV text format for porting to other EQs):

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NEW (May 18, 2016): v0.9b Impulse Response for Convolvers (eg. Foobar2k's Impulse Response Convolver plugin):

New:
- every sample rate
- 64bit versions for extra quality (if your convolver supports them)
- phase issues corrected, can now be faded out to reduce their intensity (eg. Foobar Convolver 'Mix Adjust').

64-bit float (refers to the audio format, not the OS):
r-i-l.net/_files/HD600/float64.zip

32-bit float
r-i-l.net/_files/HD600/float32.zip

source Voxengo GlissEQ presets (impulses were derived from them)
r-i-l.net/_files/HD600/GlissEQ_presets.zip

Foobar2k instructions:

The files can live anywhere - just install the Convolver plugin the usual foobar way, add it in Preferences->DSP Manager, and then 'Configure selected' and load the desired curve impulse:



New: Can now reduce the correction strengfth with Mix Adjust.

The plugin is slow to update, any changes seem to take a few seconds to kick in (audio usually glitches when it does).

Note: my impulses cause a deliberate 4dB drop in output volume, to avoid clipping/audio limiting on bass-heavy tracks. But with 'Auto level adjust' ticked this is cancelled out and you may hear strong limiting when it overloads on loud bass peaks. Untick it to avoid that.

If you still get occasional clipping/limiting, reduce Level Adjust a little.

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Curve 1: bass recovery approximated from the Sonarworks HD600 graph (Mixed filter mode) and my ears:




Curve 2: based on 1 but extended deeper.




Curve 3: recovers even more low bass, sounds very balanced to me.




Curve 4: (my favourite) as 3, but lowest node is 0.1dB hotter - great for listening, presence & kick (maybe too much for mixing?)




Note that the amount of bass probably partly depends on what's driving your cans. I use an EMU 1616m audio interface breakout box which is a little underpowered, so perhaps a little bass-shy. You may need to tweak the bass node gains a little to suit your source.

I love it, let me know how it works for you.

Just had a question about why I chose a 'dynamic' EQ.  The dynamics feature in GlissEQ is optional, you can disable it for each filter node (which I've done on my curves).  So they're just normal static EQ that you can copy to any other EQ that can match the curve.
 
Gliss actually has an Export to CVS text file feature, which dumps the filter parameters as text - that should make it easy to port the curves to other EQs.

I just noticed my presets used very CPU intensive Analyzer settings (to see detail in the low freqs).
 
I've updated the download in the 1st post.
 
Manual Fix: Spectrum -> Edit -> Block Size = 4096 (or 2048).

_gl,
 
  Would it be possible for you to simply post the settings from curve #4 above?  That would be SO much easier for me to try your settings in my graphic equilizer in foobar2000 without having to D/L and install other software.
 
I'm not sure I'm reading your curves correctly for the suggested adjustments.  It looks like  +7dB @ 37.5 Hz,  -2dB @ 115 Hz, etc.

bob a (sd) said:

  _gl,
 
  Would it be possible for you to simply post the settings from curve #4 above?  That would be SO much easier for me to try your settings in my graphic equilizer in foobar2000 without having to D/L and install other software.
 
I'm not sure I'm reading your curves correctly for the suggested adjustments.  It looks like  +7dB @ 37.5 Hz,  -2dB @ 115 Hz, etc.

Click to expand...

 
Yep, this is Curve 4.  But I recommend that you test it against Gliss so you can be sure it has translated as designed, I haven't tried but there may be Q/bandwidth differences that give different results?  Gliss has a free trial and foobar can host VST plugins with this or this.
 
(EDIT: Gain & Bandwidth headings were reversed)
 
 
CSV file:
 
 
If it's too heavy, try reducing the low shelf by 0.1db ( = Curve 3).  Let me know how it sounds.

ADDENDUM:   DO NOT do what I tried here with the graphic equilizer plugin.  Read above where _gl discusses the convolver approach.  Much MUCH saner!
 
Quote:

_gl said:

   
Yep, this is Curve 4.  But I recommend that you test it against Gliss so you can be sure it has translated as designed, I haven't tried but there may be Q/bandwidth differences that give different results? 
 
If it's too heavy, try reducing the low shelf by 0.1db ( = Curve 3).  Let me know how it sounds.

Click to expand...

Thanks!  Much appreciated.   Yes the graphics equilizer plugin in foobar2000 (foo_dsp_xgeq) has different adjustment frequency points (1/3 octave with smooth transition between frequencies) but I figure I can extrapolate your settings.  It doesn't have the filter options you have but still....
 
Here's my first attempt.  Obviously I'll need to spend some time listening with these settings.   Driving my HD600s with a Schiit "stack" (Modi2/Vali).
 

 
 
20 Hz  + 11.6 dB
25 Hz  + 10.7 dB
31.5 Hz + 4.9 dB
40 Hz  + 2.0 dB
50 Hz  + 0
63 Hz  - 0.2 dB
80 Hz  + 0
100 Hz  - 2.0 dB
125 Hz  - 1.0 dB
160 Hz  + 0
200 Hz  - 2.3 dB
250 Hz + 0.1 dB
315 Hz  + 0
400 Hz  + 0
500 Hz  -0.2 dB
630 Hz  - 0.5 dB
800 Hz  + 0
1 kHz    + 0
1.25 kHz  + 0
1.6 kHz  + 0
2 kHz  + 0
2.5 kHz  + 0
3.15 kHz  + 0
4 kHz + 0
5 kHz + 0
6.3 kHz + 0
8 kHz + 0
10 kHz  +0.2 dB
12.5 kHz + 0
16 kHz + 0
20 kHz +0
 
If you see any glaring deviations please let me know.  (Edited adjustments to try to compensate for your Q values).
 
Again thanks.  This is quite interesting!
 
Edited a second time:  Initial impressions are very favorable.  Bass is more realistic, deeper, smoother, and without boominess compared to the "brute force" bass compensation curves I had tried previously from "eyeballing" Tyll's measurements posted on InnerFidelity here:
 

 
 
Haven't voted in your poll because I don't do any mixing...just listening.

Edited a second time:  Initial impressions are very favorable.  Bass is more realistic, deeper, smoother, and without boominess compared to the "brute force" bass compensation curves I had tried previously from "eyeballing" Tyll's measurements posted on InnerFidelity here:

Click to expand...

 
That's good news, yep that's what I was going for, just correcting the can's bass rolloff in a flat way.
 
If your EQ can save a preset, can you attach it?  Love to try & compare.  I only recently set up foobar properly (did a custom touchscreen UI for my Surface Pro tablet) so I'm still finding my way around it.

Oh btw, looking at your curve it's not quite a match.  If you look at my graphs, you see that some of the filter nodes (circles) aren't always at the top/bottom of the white curve (or even on it), either because their influence combines, or because the 1st is a 'shelf', and so continues upwards + its Q value also makes it pointy.  So at 20 Hz the curve is actually over 12db.
 
With your graphic EQ you would have to eyeball that from my graphs (click them to zoom), you want to follow the white curve.  Shame your EQ doesn't go lower than 20Hz, but probably doesn't make too much difference.
 
But then with your amp it also might sound different than mine + small can variations, so if it sounds right... .

_gl said:

   
That's good news, yep that's what I was going for, just correcting the can's bass rolloff in a flat way.
 
If your EQ can save a preset, can you attach it?  Love to try & compare.  I only recently set up foobar properly (did a custom touchscreen UI for my Surface Pro tablet) so I'm still finding my way around it.
 
So at 20 Hz the curve is actually over 12db.
 
With your graphic EQ you would have to eyeball that from my graphs (click them to zoom), you want to follow the white curve.  Shame your EQ doesn't go lower than 20Hz, but probably doesn't make too much difference.

Click to expand...

 
Here's my settings for foo_dsp_xgeq version 0.3.7 :   
(The file is only 275 bytes which is why it is labeled as "0k .zip file.")  Auto leveling is OFF.
 
I also use foo_dsp_xfeed version 0.1.3 crossfeed plugin which is discussed here: http://www.head-fi.org/t/202365/best-crossfeed-plugin-for-foobar/62
 
The maximum adjustment is +/- 12dB so  although I thought I replicated your curve fairly closely.  From what you're saying I guess I need to go back and sanity check things.
 
EDITED to add:  Okay I went back and eyeballed your graph again and made the following changes:
 
20 Hz    + 12.0 dB
315 Hz  - 1.0 dB
400 Hz  - 0.6 d
500 Hz  - 0.4 dB
630 Hz  - 0.3 dB
800 Hz  - 0.2 dB
1 kHz    - 0.2 dB
1.25 kHz - 0.1 dB
 
and here are the revised settings     

_gl,
 
   Please let me know how your comparison of the foobar2000 graphic equalizer settings I've posted fare against your GlissEQ developed adjustments.

I have something similar with my HD650 - a simple 40hz low shelf filter really helps recover subbass in my opinion.

Sorry Bob, I didn't see a notification mail for thread updates, must check my ISP's spam filter.
 
I have a better idea, I will create convolution impulses of my curves that you can use directly using foobar's convolution plugin, that way it should be identical (and no tweaking required).  Will probably do it early next week, bear with me.

_gl said:

  Sorry Bob, I didn't see a notification mail for thread updates, must check my ISP's spam filter.
 
I have a better idea, I will create convolution impulses of my curves that you can use directly using foobar's convolution plugin, that way it should be identical (and no tweaking required).  Will probably do it early next week, bear with me.

Click to expand...

Not quite sure what you mean by "foobar's convolution plugin" though.  Are you talking about this?   http://www.foobar2000.org/components/view/foo_convolve .
But this sounds great.  THX!
 
ADDENDUM:  Just installed the foo_convolve plug-in and I see where it makes use of files like the one you're offering.  Again thanks... this should be quite interesting.

Yep, that's the plugin.  I haven't looked at it yet, but in general convolution can 'record' static effects like EQ or Reverb (and many other things).  It's sort of like taking a sonic snapshot, and you can then run any audio through it and it gets processed the same way.  So I will 'record' my EQ curves, and any convolution processor (like the foobar plugin) can then apply the exact same EQ without needing to mess with VST plugins.  Might have a play with it now ...

I've done the impulses for Foobar2k (see the first post for download & instructions).  Right now they're 44.1k only, so will probably only sound correct with 44.1k files.  I'll look into adding other sample rates later.  I like to upsample my CD rips 2x, if you do that then put the resampler after the Convolver (for now).
 
(the impulses might also work with other convolvers, but I'm not yet sure what a 'standard' source pulse is.  These use the 'Unitpulse2k' pulse which the foobar plug uses, there's also a Dirac pulse I can try if anyone wants it).
 
It's the first time I've done my own impulses, but they sound right compared to GlissEQ.  As I mentioned, I like Curve4 best, but the bass may be slightly over 'flat'.  If it's too much try Curve 3.
 
Let me know how it works for you.  I'm really into foobar now and have done my own touchscreen friendly skin with custom graphics & scripts.  Steep learning curve, but great for total customisation.