1. A bus limiter still on the mix bus

The single most common issue I see. The mix bus has a limiter doing 3–6 dB of gain reduction so the artist can "hear what it sounds like loud." That limiter never gets bypassed before the bounce. The file that arrives is already brick-walled.

What it costs you: Mastering can't add dynamics that aren't in the file. If the limiter has flattened the transients, the master that comes back is flatter than the song should be. The limiter on the master also has less to work with — it's already pushing into a limited signal.

The fix: Bypass the bus limiter before you bounce. Leave the EQ, compression, and saturation on the bus. Just the limiter has to come off. Re-bounce. The bounce will be quieter than what you're used to hearing — that's correct.

2. Inconsistent head/tail silence

Your bounce starts with the first note (no silence) and ends mid-reverb tail. Mastering has to either fade your intended ending or accept a hard cut.

What it costs you: Either a faded ending that wasn't your call, or a hard cut that loses the reverb tail your mix earned.

The fix: Add 0.5–1 second of silence before the first note, and at least 2 seconds at the end (more if the reverb tail is long). The full reverb tail should decay completely inside the silence before the file ends.

3. The mix bounced at the wrong sample rate

You worked at 48 kHz; you bounced at 44.1 kHz because "that's what Spotify uses." The bounce went through a sample-rate conversion (SRC) inside your DAW that may or may not have used a high-quality algorithm.

What it costs you: A subtle quality drop from a low-quality SRC. Most DAWs do this fine, but not all of them — and unnecessary SRC is unnecessary risk.

The fix: Bounce at your project sample rate (44.1 or 48 kHz, whichever you worked in). Let mastering handle any final SRC if needed for the delivery format. If you're delivering to a distributor, 44.1 kHz / 24-bit WAV is the standard.

4. The mix bounced in mono by accident

This happens more than you'd think. The stereo bus is set to mono for soloing a vocal, the artist forgets to switch it back, the bounce comes through as mono-summed even though the mix has stereo information.

What it costs you: A mono-summed bounce loses all the stereo work the mix put into placement, depth, and width. Mastering can't widen a mono file back to stereo without faking it.

The fix: Before the bounce, confirm the stereo bus is in stereo. Check the output meter — it should show distinct L and R levels (not identical). Bounce, then open the file in your DAW and check the channel count.

5. DC offset and stuck subs

A persistent low-frequency signal in the file that shouldn't be there. Caused by an automation move that didn't return to zero, a sub-bass synth left soloed, or a plugin output that drifted DC.

What it costs you: Eats headroom invisibly (peaks appear higher than they should), can make a track sound subjectively "muddy" without obvious cause, can cause speaker damage in extreme cases.

The fix: Most DAWs have a DC offset removal option on bounce — turn it on. Listen for any persistent low rumble below 20 Hz in the bounced file. If you hear nothing but the meter shows energy below 30 Hz, that's likely DC offset or stuck sub.

6. Inconsistent stem export for stem mastering

Only relevant if you're sending for stem mastering. The stems are bounced at different sample rates, different bit depths, different starting times, or with wildly different output levels.

What it costs you: Mastering has to fix the stem-level inconsistencies before doing the actual mastering. That eats time and adds risk of misalignment.

The fix: Bounce all stems from the same start point (the project's bar 1 / beat 1, not from the first note of each stem). Same sample rate and bit depth as the project. Same export settings. Stems should sum back to your stereo mix when played together at unity.

7. Hidden clipping on individual tracks

Your stereo bus output is below 0 dBFS, so you assume nothing is clipping. But an individual track inside the mix is hitting +3 dB and clipping its insert chain — that clip propagates through the rest of the mix bus quietly.

What it costs you: Distortion that's hard to hear in the bounce but obvious to mastering when the limiter pushes the signal up. Often shows up as a "fuzzy" feel on certain transients.

The fix: Run a quick scan through every channel in the mix at the inserts level. Any channel showing clip lights or output above 0 dBFS gets gain reduction added to its first insert (or its trim) until the clip light stops triggering. Re-bounce.

The 60-second tool that catches most of this

The free Mix Readiness Checklist is the catch-all I built for exactly this situation. It runs 11 automatic checks on any audio file in the browser:

• File format and sample rate
• Bit depth
• Sample peak
• True peak
• Clipping (sample count above 0 dBFS)
• DC offset
• Head and tail silence
• Channels (mono/stereo)
• Channel balance
• Bus-limiter signature (catches issue #1 above)

Plus 7 manual self-check toggles for the things the tool can't measure (e.g., "did you bypass the bus limiter?", "did you check head/tail silence in your DAW?"). Run it on your bounce before you send for mastering and the most-common issues never make it to the engineer's inbox.

The half-hour you save mastering is hours of compromise you avoid

These checks take an hour on your end — most of it just listening to the bounce front to back at a normal level. The cost of skipping them isn't always visible in the bounced file. It shows up later, when mastering returns a master that's flatter than the song should be, or a limiter on the master can't push as far as the song wants.

A clean pre-master gives mastering more to work with. More to work with means a better master. The math is simple.