Mixing Sub Sonic Kicks In Hip Hop

Posted on Posted in Music Mastering
Written by Edward Vinatea.-

Why your monitor speakers matter for mixing sub sonic kick drums

The reality is that, while most kick drums used for Hip Hop, EDM or even R&B production will sound fine on most speaker monitors, what you hear in your studio room may or may not be necessarily a true representation of the sound of your kick drums or bass sounds, not even close.

Make sure you are mixing with speakers that have a minimum 38Hz low frequency response. For Club music, or for using kick elements which are heavy in the sub sonic range, use a sub woofer, one is all you really need. In addition, If it’s also loudness what you are after {due to the increased pressure by labels and music producers to sound louder than the next artist}, then keep in mind that the higher your kick sits in the mix, the lower your overall mix level, that is, until you start crunching the kick or bass sounds with a peak limiter, you start losing all dynamics and it’s no longer perceived as a kick or bass sounds but bass “distortion’.

This is a scientific fact, not my personal opinion. If you don’t believe me, then use a real time spectrum analyzer {RTA} to prove this point . If you are looking to have both; very heavy bottom end and a very loud mix, consider working the mix alongside a mastering professional. You will find his recommendations and ability to hear with greater detail than you, crucial to achieving a loud mix that packs a tremendous bottom end.

Why he can hear better than you?

Because he has the right acoustic environment and proper monitoring system to hear “better” than you. And if you consider that he probably has more years of audio experience than you, you bet that he can help you achieve the right sound for your mixes. If you’re composing music on your own, his advice would be critical and well worth the investment. Seriously, I am not saying this just so you can hire me.

If you ignore my advice the worst that can happen is, you will have a very unpleasant surpriseĀ  when you finally get a chance to listen to your dance music masterpiece in a big club setting but sounding like there is bass rumble problem all over the place which reduces the definition of the music. Or, if you had a big brake in your career and your music is played on the radio, there is the chance that things sound too ‘bassy’, or worst; the listener hears the dreaded bass distortion which causes him to adjust his radio’s bass knob.

How can you be certain the bass is on point?

Unless you have a professional mastering set up or a mixing room where you can render – time after time – exceptionally precise mixes, you just can never tell. Sure you can always ask your Dj friend who works at the local dance club to play your rough mixes {good luck with that}, or go to as many cars with sub woofer systems you can get into to listen and take ‘mental’ notes, but since you can’t really do good A/B comparisons, it will be more like shooting a mouse in the dark. šŸ™‚ Again, good luck with that. You may have a better chance to understand what’s happening with your bass frequencies and be aware of some excessive bass energy mass if you train your eyes and ears along side a RTA or any FFT analyzer. But there is simply no free lunch and your miles may vary, so the longer you study these analysis tools, the better the overall results you will get.

Yes, understanding visual correlations can save one a bundle of time and money, so most mastering and acoustic design engineers will deny this information and call it balderdash. They do have, after all, a bunch to lose if this information becomes common knowledge. Now, I am certainly not saying that with analyzers even deaf people can master a track {sorry, deaf people}, you definitely need to hear the changes you are making sound-wise, and, understand the acoustics in your room whatever they may be. That’s another article or chapter for another time, though.

Anecdotal Article

A good customer of mine ordered mastering for one of his hip hop tracks expecting that my mastering process will make it sound good on all playback systems {as usual}. It was a very cool hip hop recording with just one sub sonic element; an 808 kick drum with no synth bass lines in the arrangement.

After delivering the product to him, I received his feedback call and he was asking “what happened to the song’s bottom end?”. He also said that “the original mix sounded better because it was bassier”, and that the bass in the master I gave to him is all but gone.

Now, I am not used to feedback like that {and frankly, I am rarely asked to do further adjustments after I master anything} but, I’ve received similar clients’ mixes in the past, so I needed to investigate all this a bit more thoroughly.

The first thing I asked my client was if he was listening this master on studio monitors. He answered, yes. Then, I asked for the brand and model of his speakers. He said that they were Samson Resolv 40A’s.

Ah-ha! These speaker monitors have a frequency response from 70Hz to 24kHz which are great to check top end, but not reliable to hear sub bass frequencies.

A quick spectrum analysis revealed that the predominant frequency in his chosen kick drum was at about 48Hz. Clearly, that 808 kick drum was nothing more than a 48Hz sine wave, or tone, and it was too low band-wise, to be accurately represented with those Samson speakers. This also explained why my client had to push the level of that kick track so high up in his mix; he was only hearing the overtones, not the all fundamentals, and certainly not its predominant frequency.

Spectral data of the original mix

The pix with red arrow below shows the lowest frequency that he apparently was able to hear with the monitors in his studio {70Hz}.

How low he heard

As a matter of fact, this was a tough mix to master because, not only was the permitted maximum level {PML} almost all taken up by this 808 kick, my client’s specifications required ‘loudness war’ competitive levels. So, not only did this track had to be very loud, but also, well harmonically balanced. Without multi-band compression at the low end, the task is simply impossible.

To see how unbalanced in the mix his kick was, I simply boosted the mix overall level by about +4dB, and the 808 kick was sounding near the point of distortion. The mix may have been no more than a total RMS power at around -14dB, which still is a comfortable level to process, but it didn’t take much boosting to have it almost fall apart.Ā  It took a two-band crossover ‘bass compressor’ {a shelf type band compressor} which clamped down at 200Hz and below, and one very narrow band compressor at 48Hz {bell type almost like a de-esser} to bring that 808 kick drum under control. Then, the rest fell easily into alignment because when you reduce one area of density, the others {in this case, mids and highs} are automatically increased by default.

Thanks to the aid of a Waves PAZ spectrum analyzer {not shown on these screen shots}, it took 15 minutes to master an otherwise good mix featuring just one bad but crucial element {the 808 kick}. Since the 808 was all that was riding at the bottom end, its perfect level in respect to the overall sound of the mix was crucial. See the spectral data of the master. Notice how the kick drum remains pretty much at the same level and all frequencies at 200 and above are higher. From the look of the spectrum, anybody would probably think that I increased the mids with a regular shelf eq filter. But, listen to what happens if you do it my way {as explained above} and with a little limiting as the last touch.

Spectral data of the master


Having said all that, what I told my client was very simple; due to the fact that he can’t judge the sound of the master with those Samson speakers, he really needs to hear the master on a playback system that has ‘sub’ woofers. Or, he needs to ask for the help of a friend who owns a car with big subs, or, ask a DJ friend in a club to play my masters. And, if he can A/B it with the original, then even better. I also told him that if he wanted me to boost the bass by one or two dB, no problem {however, this depends on the source}.

The next day, my client emails saying that he tested the mix on a system with sub woofers and the master sounded good and that he was wrong for assuming something was not on point with the mastering. He didn’t think it needed more bass either. Phew, another satisfied customer.

I couldn’t have asked for a better resolution to this job problem. Not only I don’t have to adjust the master, but it translates on all playback systems as expected.

Conclusion: To all of you who are about to send mixes to your skilled mastering engineer, i.e., Hip Hop mixes that have as a bass element only a kick drum {which is nothing more than a 48Hz tone} please, make sure you are mixing with speakers that can reach at least that low in response. If you lack the right monitors, consider not choosing a kick drum that it’s supposed to be felt rather than being heard.

A very skilled mastering guy may still be able to fix the level of your sub sonic kick, but sometimes what comes out is something you never expected to hear out of your mix. As usual, your miles may vary.

Thanks for reading,

Edward Vinatea / Mixing-Mastering Engineer

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