Post by MattB on Jul 6, 2022 7:05:09 GMT -5
Back in January I decided I wanted to build a cab sim. I couldn't find one that I thought would give me the sound I was looking for, so I ended up designing my own. It took a lot longer than I wanted, but after several redesigns and rebuilds I'm finally done. I'm really happy with the end result. It gets very close to the sound I wanted, and it has enough adjustability to get lots of other good sounds as well.
Schematic:
Layout:
SW1 selects between the two basic flavours of sound. SW1 down is the Dark Peak setting. This is the sound I was originally aiming for. The wide mid scoop gives it a more open, clear sound. SW1 up is the White Peak setting. It bypasses the first Bridged-T filter and reduces the gain to partly compensate for the increased level. The net result is less bass and more upper mids. It's a little brighter and more aggressive.
The purple line is the Dark Peak, blue line is the White Peak. All pots are at 50% and the bass and mid switches are in the middle position.
The Lo Freq pot is basically a bass roll-off. The low peak can be varied from aorund 75Hz to about 170Hz. At the lowest setting the -3dB point is below 60Hz, so there is some extra low end available for a baritone or 7-string if you want it. In standard tuning there isn't any point going below about 30% rotation.
This shows the Lo Freq control stepped in 25% increments.
SW3 boosts or cuts the bass by about 2dB. It's a small change, but I find it useful for balancing the bass level of different settings. It also slightly affects the mids- the boost setting deepens the mid notch and the cut setting reduces it. The change in mid level is too small for me to hear- it's just over 0.5dB in either direction.
SW2 controls the depth of the second Bridged-T filter. It has 3 settings spaced just over 3dB apart.
The first chart is in Dark Peak mode, the second is White Peak mode.
The Hi Freq control varies the high end peak from about 3kHz to 4.2kHz. The Hi Lvl control has about 10dB of adjustment range. Between the two there are lots of good sounds available. The Hi Lvl control has a bit more range than it needs, but I think the extra sounds can be useful even if some of them aren't all that realistic.
First chart shows the Hi Freq stepped in 25% intervals with the Hi Lvl at 50%. Second chart shows the Hi Lvl stepped in 25% intervals with the Hi Freq at 50%.
And finally, a comparison between the Kinder Trespass and the frequency response charts for two real guitar speakers.
