So, I was poking around in the T-RackS manual, and noticed that it says that the EQ PA band-pass filter "the filter high-passes the signal with a broad 4th order high pass at 100 Hz, while the low pass filter starts the 4th order slope at 5 KHz."
I'm curious why those frequencies were chosen for the EQ PA when the bandpass on the original hardware is set at 50Hz and 15kHz?
https://apiaudio.com/product_specs.php?id=106
The UAD version gets it right:
https://www.uaudio.com/uad-plugins/equa ... ction.html
@Peter, do you know?
T-RackS EQ PA
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- KVRian
- 1073 posts since 8 Mar, 2009
Unit they based their model on must have been old and the values drifted, or it was miscalibrated from the beginning?
I don't think it matters much anyways as a lot of the T-Racks EQ models aren't much better than some purely digital EQ's (most of em cramp apart from the Sontec if i recall correctly)IMO and not a scratch on something like EQuilibrium, which can do a decent take on the linear part of API stuff with its zero latency analog mode. The only thing none of them do is the per band nonlinearities for whatever reason, but API's EQ's have op-amps in every band, not just on the output. The preamp in the T-Racks model (a lot of plugins really)just stick it at the end as if it was half a passive EQ. You can't exactly drive the individual bands on the API into distortion like you can cheap desk EQ's at least not the 5500 i own(maybe with a lot of padding you could) but it definitely makes a big difference in the sonority of analog active EQ's i have found
I don't think it matters much anyways as a lot of the T-Racks EQ models aren't much better than some purely digital EQ's (most of em cramp apart from the Sontec if i recall correctly)IMO and not a scratch on something like EQuilibrium, which can do a decent take on the linear part of API stuff with its zero latency analog mode. The only thing none of them do is the per band nonlinearities for whatever reason, but API's EQ's have op-amps in every band, not just on the output. The preamp in the T-Racks model (a lot of plugins really)just stick it at the end as if it was half a passive EQ. You can't exactly drive the individual bands on the API into distortion like you can cheap desk EQ's at least not the 5500 i own(maybe with a lot of padding you could) but it definitely makes a big difference in the sonority of analog active EQ's i have found
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- KVRist
- Topic Starter
- 151 posts since 24 Mar, 2020
The API models cramp for sure. As does the Pultec. The APIs also have a resonant HP rolling off at 10hz always, even with the EQ button flipped off. Interestingly the Classic EQ also cramps but much less so than the APIs even though it's older. The Liner Phase EQ doesn't really, and the Master 432 doesn't cramp at all.
It appears IK have decided that cramping is desirable for some of the models of Analog EQs, since they came after they've built algorithms that don't cramp - but that doesn't make sense. There is a mystery to be solved.
It appears IK have decided that cramping is desirable for some of the models of Analog EQs, since they came after they've built algorithms that don't cramp - but that doesn't make sense. There is a mystery to be solved.
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- KVRian
- 1073 posts since 8 Mar, 2009
That's probably part of their attempts to emulate the transformers in the circuit. If you really wanted to simplify the model, or only focus on the linear properties of a transformer, it's a bit like a really wide bandpass filterart&sound wrote: Wed Apr 28, 2021 10:25 pm The API models cramp for sure. As does the Pultec. The APIs also have a resonant HP rolling off at 10hz always, even with the EQ button flipped off..
I don't think their is much mystery other than the fact that the modelling doesn't live up to their hype. Their tape model is really good though. Amps, comps and EQ's less so for me at least.
Horses for courses and all that
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