A diagnostic encyclopedia of the 15 most common mixing problems — with causes, symptoms, and fixes.
The mix sounds dull, unclear, and lacking definition. Instruments blend into a muddy wall of sound where nothing cuts through.
200-400 Hz Energy buildup in the low-mid range. This is the #1 issue MixDiagnose detects. Caused by:
• No high-pass filtering on non-bass instruments
• Too many tracks occupying 200-400 Hz simultaneously
• Bass guitar and kick drum both fighting for the same space
• Room modes in untreated studios boosting this range
1. High-pass filter everything except kick, bass, and sub at 80-120 Hz
2. Cut 2-3 dB at 300 Hz on tracks that sound muddy individually
3. Use EQ to carve space — if bass is prominent at 250 Hz, cut guitars at 250 Hz
4. Check if your room is boosting 200-400 Hz (untreated rooms almost always do)
The mix sounds piercing, especially at loud volumes. Listeners want to turn it down. Fatiguing after a few minutes.
2-5 kHz Too much energy in the harshness zone. Caused by:
• No de-essing on vocals
• Electric guitars with natural resonance at 3-4 kHz
• Synths with bright waveforms not filtered
• Microphone positioning too close to the source
1. De-ess vocals (target 5-8 kHz for sibilance, 2-4 kHz for harshness)
2. Cut 1-2 dB at 3-4 kHz on harsh instruments
3. If the whole mix is harsh, try a gentle 1 dB cut at 4 kHz on the mix bus
4. Check with fresh ears after 24 hours — ear fatigue makes you over-boost highs
Mix lacks warmth and body. Sounds like it's coming through a phone speaker even on full-range monitors.
Insufficient energy in 100-300 Hz. Usually caused by over-aggressive high-pass filtering or cutting too much from the low-mids.
1. Check your high-pass filters — are they set too high? Vocals at 80 Hz, not 150 Hz
2. Add warmth with a gentle boost at 150-250 Hz on bass and rhythm instruments
3. Don't confuse "clean" with "thin" — some low-mid energy is necessary for warmth
The mix has no impact. Drums don't hit. Transients are smooth but boring. Everything sounds the same level.
Crest factor below 6 dB — the mix is over-compressed. The dynamic range that makes music feel alive has been squashed out.
1. Remove or reduce mix bus compression
2. Compress individual tracks instead of the bus
3. Use parallel compression for drums — keep the uncompressed signal for punch
4. Target crest factor ≥7 dB (check with MixDiagnose)
5. Make sure your limiter isn't squashing transients — use true peak metering
Can't understand the lyrics. Vocal gets lost when other instruments enter.
Vocal is masked by other instruments in the 1-3 kHz range, or simply mixed too low.
1. Boost vocal 1-2 dB at 2-3 kHz for presence
2. Cut 1-2 dB at 2-3 kHz on competing instruments (guitars, synths)
3. Use sidechain compression on instruments that mask the vocal
4. Check vocal level — should be clearly intelligible at all times
5. Close your eyes — can you understand every word?
Bass and kick are overwhelming. On speakers, the room shakes. On headphones, the low end is fatiguing.
Too much energy in 20-80 Hz. Sub-bass is not controlled.
1. High-pass the mix at 20-30 Hz (remove inaudible sub-bass)
2. Sidechain kick to bass for clarity
3. Check if 808 samples have excessive sub energy — use a low shelf cut
4. Monitor on systems with subwoofers — phone speakers won't reveal this
Mix sounds wide on headphones but disappears or sounds weird on speakers. Elements sound "hollow" or "phasey."
Phase cancellation between left and right channels. Usually from stereo widening plugins, duplicated tracks with slight timing offsets, or poor mic placement.
1. Check mono compatibility — sum to mono and listen
2. Remove stereo widening plugins and check if the problem goes away
3. Keep low frequencies (below 120 Hz) in mono
4. Use a correlation meter — should stay above -0.5 at all times
5. Time-align duplicated tracks exactly (sample-accurate)
Harsh distortion on peaks. The master meter hits 0 dBFS. Audio sounds crunchy on loud transients.
Individual tracks or the mix bus exceeding 0 dBFS (digital full scale).
1. Gain stage: pull every track down so peaks sit at -6 to -12 dBFS
2. Add a trim plugin at the start of each channel strip
3. Check for clipping on individual tracks, not just the master
4. Use a true peak limiter set to -1 dBTP on the mix bus
5. Never let red lights flash on any meter — ever
Mix has no dynamic range. Quiet and loud parts are the same volume. The mix sounds "small" despite being loud.
Too much compression — either too many compressors on individual tracks, or heavy bus compression. Crest factor below 5 dB.
1. Bypass all compression and listen — does the mix sound more alive?
2. Keep compression on individual tracks where needed (vocals, drums)
3. Remove or drastically reduce bus compression (2:1 max, 2-3 dB gain reduction)
4. Target crest factor ≥7 dB
5. If you need loudness, achieve it in mastering, not mixing
"S" and "T" sounds are piercing. The vocal hurts on consonants.
Excess energy at 5-8 kHz from the vocalist's natural sibilance, amplified by compression.
1. Use a de-esser plugin (target 6-8 kHz, adjust threshold)
2. If de-esser isn't available, automate volume dips on "S" sounds
3. Cut 1-2 dB at 7 kHz on the vocal channel
4. Check mic technique — off-axis positioning reduces sibilance
Two instruments sound great alone but muddy together. Elements "compete" and neither is clear.
Two or more instruments have overlapping frequency content. The ear can't separate them.
1. Identify which frequencies each instrument occupies using a spectrum analyzer
2. Carve space: if guitar is at 2 kHz, cut the synth at 2 kHz (or vice versa)
3. Pan instruments apart to create separation
4. Use sidechain compression to duck one when the other plays
5. Decide which instrument is the priority in each frequency range
Mix sounds great in stereo but thin or hollow when summed to mono. Elements disappear.
Phase issues from stereo widening, mid-side processing, or duplicated tracks with timing differences.
1. Check mono regularly during mixing (most DAWs have a mono button)
2. Keep low frequencies mono (below 120 Hz)
3. Remove or reduce stereo widening plugins
4. Ensure mono compatibility before adding any stereo enhancement
Mix sounds distant, washed out, like it's in a tunnel. No intimacy or directness.
Too much reverb, or reverb on too many tracks. Reverb tails overlap and create mush.
1. Remove reverb from most tracks — keep it only where needed
2. Use pre-delay (20-50 ms) to maintain clarity before the reverb tail
3. Use shorter decay times (1-2 seconds for most genres)
4. Try EQ on the reverb return — cut lows below 200 Hz and highs above 8 kHz
5. Use less reverb on lead vocals — they need to feel "in your face"
Mix is already at -8 LUFS with true peaks at -0.2 dBTP. There's no room for the mastering engineer to work.
Mixing too hot — the mix is essentially pre-mastered. Limiter on the mix bus is crushing transients.
1. Target -18 to -14 LUFS for a pre-master mix
2. Keep true peaks below -3 dBTP
3. Remove the limiter from the mix bus — that's mastering's job
4. If you need to check loudness, use a separate limiter on a copy, not the main mix
5. Leave at least 6 dB of headroom for the mastering engineer
Background hiss is audible in quiet sections. Noise builds up across many tracks.
Analog gear noise, mic preamp hiss, or digital plugins adding noise floor. Multiple tracks each add a small amount of noise that compounds.
1. Gate or clip-gain automate tracks to silence during empty sections
2. Use noise reduction (RX, Denoiser) on noisy recordings
3. Check gain staging — low input levels require more preamp gain = more noise
4. Print stems with silence removed
5. Use noise gates on drums during gaps between hits
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