Headrush Impulse Responses
Birch115
Inspired by Ashdown® 1x15 (Bass Cab)
Typical interpretation:
- Birch → cabinet in birch plywood
- 115 → checkout 1x15” (one 15 inch cone)
Sound character
This type of IR is very different from 4x12:
- deep and round bass
- less aggressive
- softer mids
- wider response
Typical for:
- clean
- jazz
- ambient
- bass guitar
- vintage / doom / stoner guitar
Recommended Parameters
Gain (dB)
Adjust the IR level
With IR 1x15: often more “full” → less gain is needed
Examples:
- Clean: -4 dB
- Environment: -5 dB
- Doom: -7 dB
Rule: avoid saturation on the low end
HiCut (Hz)
Cuts high frequencies
The Birch115 already has few highs → DO NOT cut too much
Realistic range:
- 4kHz → 8kHz
Examples:
- Clean jazz: 5 kHz
- Environment: 6 kHz
- Doom: 7 kHz
Rule: too low HiCut = “muffled” sound
LoCut (Hz)
Cuts low frequencies
This is CRUCIAL: the 1x15 produces a LOT of bass
Realistic range:
- 80Hz → 150Hz
Examples:
- Clean: 90 Hz
- Environment: 100 Hz
- Doom: 110–130 Hz
Rule: too low = mud too high = you lose body
Mix (%)
Blend IR / direct signal
Standard use:
- 100% → always for guitar
Creative Use:
- 70–90% → ambient / texture
Pro Tips
Great starting point:
- Gain: -5 dB
- HiCut: 6 kHz
- LoCut: 100 Hz
- Mixes: 100%
If the sound is:
- too “boomy” → raise LoCut
- too dark → raise HiCut
- poorly defined → lower Gain
Setup Examples
Clean Jazz / Warm
Gain-4 dB
HiCut5 kHz
LoCut90 Hz
Mixes100%
Sound:
- warm, round, natural
Ambient / Shoegaze
Gain-5 dB
HiCut6 kHz
LoCut100 Hz
Mixes90–100%
Sound:
- wide, soft, spatial
Doom / Stoner
Gain-7 dB
HiCut7 kHz
LoCut120 Hz
Mixes100%
Sound:
- big, dark, powerful
Bass (alternative use)
Gain-6 dB
HiCut4.5 kHz
LoCut70–80 Hz
Mixes100%
Sound:
- deep and controlled