Preparing your audio files for working with a mix engineer / producer

Congratulations! You’ve decided that you want to take your music to the next level so you’ve hired a mixing engineer or producer. You’ve discussed how you want your track to sound, negotiated fees and worked out what particular brand of fairy dust the engineer is going to use… all you’ve got to do now is send over the audio so they can work their magic, right?


I decided to write this blog after reflecting on some of the experiences I’ve had working with audio brought to me by my clients. In some cases it’s audio they’ve recorded themselves – they may have even done a bit of editing or mixing on it too – or it’s come from another studio where they did the tracking. Either way, there is usually some work involved in getting it ready to mix.

Now I get it, as an independent artist you’re often on a tight budget and need to make sure you get the most out of your sessions. So let me help you with that right now: here are a few things you can do ahead of the session to ensure that whoever you hire doesn’t spend half the session tidying it up instead of mixing it for you.

Don’t get me wrong though, if you really don’t want to tackle any of these and are happy to pay someone to do it for you, then that’s fine. I for one will happily take on these prep tasks. But if you’d rather whoever you choose to work with can get down to doing their mix thing as quickly and easily as possible, then follow these steps:

Stems or Session files?

Determine if the mix engineer uses the same DAW as you and can thus use your session files directly. Most engineers will support a range of DAWs:  for instance I have Pro Tools , Logic, Ableton and Reaper. If they don’t, you will have to export audio stems for each track in your project. In some ways this is easier for the mix engineer as they don’t need to worry about deciphering someone else’s project setup, but most of the following observations will still apply before you render.

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Rendering stems in Reaper

Fade / x-fade your edits

Wherever you have edited audio clips, fade-in the start and fade-out the end of the clip, or where you have edited together audio clips, ensure there is a cross fade. I can’t emphasise this enough: I’ve had audio stems delivered with clicks and pops embedded in them as the edits hadn’t been cross-faded. It’s simple to do at the time and not doing it eats up way more time and effort further down the line – time that could be spent mixing.

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Using Fades on the boundaries of audio clips in Pro Tools

Name tracks meaningfully

Your mixer won’t have worked on this project with you for the last three years, so they won’t know the channel labelled ‘Bob’s wanger’ is actually a guitar part. So name the channels in a way that makes sense, and if a channel is labelled Peruvian nose flute then make sure there are only Peruvian nose flute parts on it. Obvious maybe, but it can and does happen, for instance when you’re recording through a single input channel and adding different instruments without creating new tracks.

Clear and meaningful track naming in Logic Pro X
Clear and meaningful track naming in Logic Pro X

Group your tracks by instrument

Keep all same / similar instruments together in adjacent tracks. So, all the drum kit tracks together, or multiple layers of guitar for instance. You don’t necessarily need to group them through busses or set up mix/edit groups as this is something the mix engineer may or may not do depending on their workflow.

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Track organisation in Ableton


Assuming you know the best takes for each instrument, assemble your various takes of a particular instrument / vocal into a single comp and consolidate it, making sure you check your fades / x-fades too. You can keep the old takes on a separate track in case you need to go back in there for something later on.

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Comping with playlists in Pro Tools


Generally, get rid of any EQ / compression / reverb added on the tracks, unless there are specific sounds you want to keep or illustrate to the mix engineer (for instance that gnarly delay you love or the way that filter sweep moves). Also remember that the engineer may not have the same plug-ins as you, so if there’s something you can’t live without, freeze / commit / bounce it down to a new track so it can be incorporated in the mix.

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Unless it’s an integral part of the sound, remove all unnecessary plugins


Unless absolutely necessary to demonstrate a particular effect or sound, remove all automation, especially channel volume / pan / mute automation as this can really confuse things. It’s usually not immediately obvious if there’s active automation on any parameters unless you specifically view the automation lanes. Make sure the automation settings are not in write mode either.

If you do need to automate volume (e.g. to balance gain between sections), ideally use clip gain (see the next point), or place a gain / trim plug-in in the channel and automate that.

Automation in Logic Pro X
Automation in Logic Pro X

Balance clip gains

Most DAWs support clip gain – use this to balance the levels of clips on each track so that the channel faders don’t need to be moved to extremes in order to hear something, and that all parts on a track are at roughly the right volume to be heard.

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Clean it up

Remove any unused channels or muted / unused audio from the project, unless it’s stuff you think you may need later in the mixing process (e.g. that banshee wail you’re not quite sure about, or those 50 extra guitar / synth layers that you might want in the mix but can’t quite decide on yet). There’s no point in transferring 120GB of data when 110GB of that is out-takes that aren’t going to be used. This especially applies if you are transferring your files over the internet.

Use the ‘strip silence’, ‘compact’ and ‘save a copy in’ features of your DAW if they have them to remove unnecessary audio and files. Most DAWs have good file management features these days.

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Use Comments / Labels / Notes

Help the mix engineer navigate the song by using labels / comments / notes. This is especially important if you are not going to be attending the mix session –any accompanying notes will always be useful.

Remove any tracking-specific routing

Sometimes the audio will have been recorded in a studio with a console or other hardware for monitoring, or you may have a quirky recording set-up at home, and the project will have its I/O routing set up for that specific system. Remove the routings and set them so that all the tracks play back to a single master bus, this ensures that everything that has been recorded will be heard.

Fade / X-Fade your edits

Did I mention this? Well let me say it again, Fade / Cross-Fade your edits!

Do all this, and your mixer will be able to spend their time doing what they do best – and you can get the most out of your budget.  

DIY Sub Kick

The concept of a sub kick is very simple, take a large speaker and use it in reverse as a microphone specifically for picking up low frequency information, from a kick drum for instance. This can be used in the mix to reinforce the sound of the kick alongside another kick drum mic,  providing additional depth to the sound due to it’s focus on the sub 100Hz frequency range. The subkick won’t pick up much spill from other parts of the kit either, and a good trick is to use it to trigger a gate on the internal kick drum mic, to get a very tight and clean kick sound.

Various companies make them, the  Yamaha SKRM100 for example, which is essentially a 6.5″ woofer mounted in a small drum shell, with mesh either side and a built in stand. The price, £350, quite a bit for speaker on a stand! Over the years I’ve seen various DIY versions in studios around the way including an NS10 woofer clamped into an old worktop vice as a base, all these incarnations functioned well, and cost significantly less than £350 to make. Time to get the tools out I thought.

This is an easy DIY project, it involves mounting a woofer speaker into a suitable frame (in this case a tambourine shell), and then a little soldering to attach an attenuator and a male XLR connector.


First start with a speaker, I went for an 8″ Wharfedale woofer of EBAY (approx £18), you can use anything from 6″ up, though some say it doesn’t work as well with larger speakers. I’m not sure about that, the 8″ seems to work pretty well. Most important is the speakers frequency response, it should go down to about 20Hz to get all those sub bass frequencies.


I thought a lot about how to mount it, I wanted something that would isolate it and look good, but not cost too much. The cheapest and most elegant solution I could think of was to use elastic hairbands to suspend the speaker within the circular frame of a tambourine (without the jingles of course). So I ordered a 10″ tambourine (£7 Ebay) and removed the jingles by pulling out the nails holding them in place.


Slip the elastic hairbands through the screw holes in the speaker, then feed each end through one of the slots in the tambourine rim and push the upper loop (the one that goes over the rim) round and under so the 2 loop ends overlap. Take the nail that used to hold the jingles in place, push it back through it’s location hole so that it pegs the 2 loop ends of the elastic in place. Push all the way in so it’s secure. That was probably the trickiest step in all of this, required a lot of patience to get the elastic and the nail to all go in the right place. Repeat this for the remaining screw holes.


The next challenge was figuring out how to mount the the subkick using a normal mic stand. I happened to have a broken mic stand lying around so I took the pivot mount from it (the bit that screws onto the top of the vertical part of the stand and allows the boom to attach to it and swivel up and down). The advantage of using this was that it had a standard screw thread on the end which meant I could attach it to a regular mic stand (as shown in the picture above). The pivot mount itself attached to the tambourine rim with a nut, bolt and a couple of washers (through one of the existing slots in the tambourine).

Next step is connecting it up to a mic pre-amp. The output of the subkick is pretty hot, an attenuator (or pad) is recommended to bring the signal level down to the region expected by most pre-amps. You can buy an inline attenuator that connects between the subkick and the XLR cable to the pre-amp, or you can knock together a basic potential divider circuit to do the job for you. I opted for the latter as you probably guessed. Another point worth mentioning here is that I’m going to use an unbalanced connection, providing the environment isn’t to (electrically) noisy and cable runs are short, this shouldn’t be an issue. If you wanted to go for a balanced connection, you would need to wire in an audio transformer, and to get one that has good sub-sonic frequency response isn’t going to be cheap. You could also use a DI box, again, a good quality one with good bass response would be preferable.

Circuit 1

The schematic for an attenuator circuit is shown above, I used a simple potential divider, the values I chose for the resistors R1 and R2 are:

R1=680 Ohm , R2 =150 Ohm

There are many combinations you could use and they also depend on your speaker, Google “attenuator for Subkick” if you want to get lost in that world!



With the resistor values chosen, I soldered them directly to the speaker terminals and covered them with heat shrink. Easiest way I found was to solder one end of R2 to the speaker – terminal, and one end of R1 to the speaker + terminal, slide a sheath of heat shrink over each resistor then twist the exposed ends together, before applying heat to shrink the insulation (see above).


I then soldered a short length of guitar cable to the speaker – terminal and the exposed resistor ends, ensuring I had a sleeve of heat shrink in place to insulate the connection.


Finally I soldered the male XLR connector onto the end of the cable, (Pin 1 to Speaker -, Pin 3 to the resistors, Pin 2 unconnected). I had a retaining clip lying around so I used that to secure the connector to the frame, so as not to put too much mechanical load on the soldered joints.

So there you have it, a fully functioning subkick that doesn’t cost an arm and a leg, doesn’t look to shabby, and is not to difficult.


Here is a quick audio example of the subkick in action. The audio is as follows

Bars 1-2 : Internal kick mic only

Bars 3-4 : Subkick only

Bars 5-6 : Internal mic + Subkick

Bars 7-8 : Internal mic + Subkick (with gate on subkick)

Bars 9-10 : Full kit, no subkick

Bars 11 – end : Full kit with Subkick

Recording a 9-piece latin band (in layers) – Timbaterra Salsa EP

This recording of the Bristol-based latin band Timbaterra comprises 4 tracks covering Reggaeton, Salsa Romantica and modern salsa styles with influences from Cuban Timba. Recorded in Bristol and featuring vocals of Indira Roman and Sandra Lord, and the piano and vocals of Raimundo “El Nene” Fernandes. Rhythm section features Rory Francis playing all percussion, myself on bass and the horns were played by Ralph Tong (Trumpet) and Dave Smallwood (Trumbone).

The aim of this recording was to get the full sound of a 9 piece latin band, but doing it in layers rather than everyone playing together live. The key to this is having a good, grooving rhythm section  foundation to build the rest of the tracks on.  Thus we first layed down bass, piano and percussion together, the percussion was done timbales first to get all the breaks marked out, then we overlaid the congas, bongos, guiro and cowbell. I borrowed a set of Audix drum mics for the percussion, mic’ing the timbales with a pair of overheads and 1 dynamic under each drum, then individual mics on the snare, kick and bell tree.

Vocals were done next, fantastic performances from everyone made this very quick and easy. I used an Electrovoice RE20 for all the lead and layered background vocals, worked very well on these voices.

Finally the horns were done, we couldn’t get both players in at the same time so had to go with layering each part individually. This makes things a bit more tricky in the mix when it comes to making it sound like a section, but not impossible. Again, the RE20 microphone did the job of tracing the horns, I used it about a metre away and it seemed to capture the tone nicely.

Once recorded, the mixing began in earnest. Although I’d played in latin bands for years, I’d never recorded and mixed latin music, the learning curve was steep! Thankfully Raimundo was there to bounce the mixes off, he patiently listened to a lot of iterations before he finally said, “yes, that’s it!”.

In a nutshell, the cowbell needs to be prominent (but obviously not too prominent, unlike here), the congas driving and the rest balanced. Obvious right? Took me a while to get it though. A lot of work went into gelling the horns together to sound like a section rather than individuals playing in separate sessions. I used sample replacement to reinforce the kick and snare drum sounds too, adding more punch than was available in the original recorded sounds.

I also go the opportunity to trial a Universal Audio Apollo system, and used the UAD analogue emulation plugins to mix the songs with. Specifically, I used the Studer A800 tape sims on each instrument bus, the EMT 140 plate reverb as a general reverb, the Neve 88RS channel strips for the percussion, Cambridge EQ and LA-2A and 1176LN compressors for vocals and horns. The overall effect was amazing, I got closer to that sound I was searching for than I ever managed with all the other plugins I’d been using. So blown away was I that I decided to invest and bought an Apollo and a bunch of plugs, haven’t regretted that decision!

I’ve been studying Mastering courtesy of Ian Shepards Home Mastering Masterclass (which I thoroughly recommend by the way), I thought I’d put some of that knowledge to the test and do my own masters on these tracks too. Still learning on that front, there is a lot information to absorb and experience to gain. During the mix process the band had a regular gig at a salsa club, so we had opportunity to test out the mixes on a larger sound system and get an idea of how people responded (they danced!)

All in all I’m very happy with the way this recording came out, it took a while but I had a lot to learn, I’m  looking forward to doing a lot more latin music in the future.