(By Mastering The Mix Contributor: Nick Messitte)
It started with a text from Jonathan Birkholz, a musical genius who plays in two of my favorite indie bands (Soul Cannon and Super City): Could I mix and master a solo project in a week?
There were many reasons to decline, chief among them the idea of mixing and mastering a project; I firmly believe one should either mix or master. To do both is almost an impossible task, especially in that limited timeframe.
But I love working with Jon. Even more than that, I love a challenge.
If I were to say yes, I’d need every tool at my disposal to stay impartial. I had to preserve the mixing and mastering mindsets as distinct entities, and never lose perspective.
Around this time, I heard much ado about a plug-in called BASSROOM, and I was intrigued: I’d moved into a new studio six months prior; I was still feeling out how bass felt in my room. Any tool to help me balance the low end would be welcome—especially one with the good press of BASSROOM.
Beyond wasting a modicum of time if the plug-in didn’t work, and plonking down $61.17 if it did, what was there to lose?
Turns out nothing. So I’d like to walk you through the process of implementing this plug-in on the master channel and show off some practical reasons why the plug-in works so well. Think of this as part client testimonial, part tutorial, and part technical explanation.
But first, a brief word on the conditions of the mix, so you can understand how I implemented BASSROOM in this instance.
The Project and the Mix
Jon’s project is called Synthscape, and it consists of four synthesizers and a hard-hitting gospel drummer. Think Sonic the Hedgehog played by jazz musicians, and you’ll have a good idea of the sound.
I used nothing fancy for the mix—just channel strip plug-ins, delays, verbs, parallel compression, and my analog chain (broad tonal shaping, a little widening, and glue). Once I got my analog chain right for the first tune, I didn’t touch a knob for the rest of the record. No plug-ins were used on the stereo bus during mixdown.
Prepping for BASSROOM Implementation
As I had already gone through a colorful analog loop, I decided to master in the box. I also opted to postpone using my trusty Sennheiser HD 650s till after the mix.
This would help me maintain perception during the mastering process; In these situations, I find it necessary to avoid mixing and mastering on the same playback systems.
That isn’t to say I worked exclusively on headphones. My secondary pair of loudspeakers, which I hadn’t used during mixdown, were employed in mastering to combat common headphone issues.
Before any EQ decisions, I raised the level of the first mix and chose a limiter. I always shoot for the final level at the beginning of the mastering process, for how can I make accurate EQ adjustments if I’m not hearing them at the level of delivery?
In shooting out a limiter, I asked myself the following questions: Which one did the least harm? Which limiter preserved the instrument relationships? Which preserved the integrity of a kick, a snare, a synth, a cymbal?
Once that was sorted, it was on to EQ choices, starting with BASSROOM.
Playing with BASSROOM Outside Genre Conventions
BASSROOM allows you to utilize target presets for many genres, but “Sega Genesis meets gospel” is hardly typical. Luckily, the plug-in also lets you import custom targets from your own files, so I loaded “Parsec” by Stereolab, the most appropriate reference Jon had sent me.
Next, I ran BASSROOM across the loudest passage of the mix. I noted the suggested target indicators wouldn’t keep still; was this the norm?
I rushed to the forums for the answer: apparently, it takes a few passes; after a minute, the indicators settled down. I dragged each band to the suggested target and tuned everything by ear a bit further.
What did I notice? A/B’ing between bypassed and processed signal revealed subtle changes. Whatever was going on, the integrity of my low-end balance was preserved.
BASSROOM’s guiding hand didn’t force me into a bad tone, in other words. But was it beneficial? Did it translate to other playback systems?
I left the HD650s and checked BASSROOM on a variety of playback systems, and that’s when I became a convert:
On every system, from studio monitors to earbuds, I heard an appropriate low-end, one that didn’t bloom in unwelcome frequency bands. The kick and bass rang independently and cleanly, all without messing with mix’s cohesion.
Remember, the only processing at this point had been a level boost, BASSROOM, and limiting, in that order. Now I had the confidence to start using this plug throughout the mastering process.
For the rest of the mixes, I placed BASSROOM second in my chain after a gain boost. This was followed by DMG Audio’s Equilibrium, and occasionally (depending on the tune) a compressor for 1 dB of clean gain reduction. Gullfoss for sweetening came next, followed by limiting.
Another important order of operation:
As I mastered each song, I loaded each finished track back into BASSROOM for target analysis. Now each new master could benefit from the sound of the previous tune.
I believe this helped me achieve tonal congruity across the album.
Why Did BASSROOM Work?
To answer this question, let’s look under the hood, using DDMF’s Plugin Doctor for analysis. At flat settings, everything is unaltered:
Boost the band between lowest band by 4 dB, and you wind up with this:
Note we’re not seeing smooth movements as we slope up and down from the 4 dB boost around 40 Hz. We see palpable “wiggling” as we hit 0 dB.
This might look weird compared to a similar boost in FabFilter Pro Q 3—a gold standard EQ if ever there was one:
This looks a bit “smoother”, but therein lies the rub: the all-important phase shifting. Here’s a plot of BASSROOM’s phase-shifting at these settings: 
And here’s FabFilter Pro Q 3:
Pro Q 3 gives us noticeable phase shifting, and we don’t necessarily want that. Why?
Phase-shifting alters the timing of the affected frequencies in relation to everything else. So we’re changing the perception of when the bass frequencies arrive at our ears—which means altering the integrity of the mix ever-so-slightly.
Now, this can often be good. Phase-shifting is part of what makes colorful EQ’s sound colorful.
But in mastering, color is sometimes not desired—especially if we already like the color of the mix, as was the case here.
FabFilter can also operate in linear phase mode, and this should fix the phase-shifting issues. Indeed, it does:
But is this really better?
See, linear phase EQ can introduce a transient-smearing issue called “pre-ringing.” It’s difficult to explain, so let me demonstrate the issue:
Here’s a programmed snare with a sizeable, narrow boost at 166 dB (courtesy of Pro Q3).
And here’s that same snare, but with the EQ operating in linear phase mode.
Note the “whoosh” sound anticipating the snare hit. This is pre-ringing, made exaggerated so you can really hear it. Mastering engineers tend to avoid pre-ringing as much as possible, especially in the bass, where it can be more audible.
Music is filled with thousands of moving parts—frequencies that bounce all over the spectrum, instruments moving in dynamic ways. Use linear phase EQ across a master, you risk introducing weird artifacts (pre-ringing); go with other kinds of EQ, and you risk altering the timing of the whole mix.
It’s quite the compromise!
Here’s where BASSROOM really shines: not only is it easy to use, it also gives us a “best of both worlds” scenario for broad-strokes tonal shaping in the low end.
Let me show you:
This is the mix of “Punisher” with gain and limiting applied—but no BASSROOM.
And here’s the tune with BASSROOM employed:
This isn’t the final master—you can hear that here. These examples represent the first step I took in EQ’ing the sizeable low end of this mix.
Let’s look at the settings:
And here’s what these curves looked like in Plugin Doctor:
The phase response?
I was able to match these curves pretty much exactly in Pro Q3:
Though it took 15 different nodes:
Even so, the phase response of FabFilter Pro Q doesn’t match up to BASSROOM:
There is noticeable phase-shifting between 50 and 200 Hz. It could alter the inherent feeling the mix, because it’s changing the timing of bass frequencies ever so slightly.
I could switch FabFilter Pro Q 3 into linear phase mode, and it would chart better on a graph:
But then we introduce the possibility of pre-ringing.
Would it be audible? With so many moving parts in this mix, it’s not something I’d want to risk—especially if I didn’t have to!
Now, who’s to say that BASSROOM isn’t causing pre-ringing? Well, my suspicions tell me it doesn’t. For one thing, even the narrowest Q values aren’t that narrow, and for another, you can only boost around 4 dB in a single instance.
But let’s push the limits just to be certain; let’s see if we get audible pre-ringing when piling three, narrow instances of BASSROOM on a sampled snare. This test attempts to mirror the settings we achieved with FabFilter Pro Q3–the test that clearly showed what pre-ringing sounds like.
Here’s what we have with 16 dB of a BASSROOM boost:
That doesn’t sound like pre-ringing to me.
Conclusions
I’m pleased to welcome BASSROOM into my arsenal of EQs. But I’d like to offer a final word on its operation:
You would not be blamed in thinking that this plug is a “matching tool”; indeed, that’s one of the ways to use it.
I totally understand if matching EQs go against your mastering morals. I’ve never used one that worked for me.
Nevertheless, I would advise you to check out this plug-in for its curves and for its phase response. No one is ordering you to use the EQ with its targets, though you might indeed find them helpful.
You might find within them a room of choices for your bass equalization needs.
Forgive the pun!
