Not getting line levels into & out of Daisy Seed

Troubleshooting and Support
1

Hey guys,

I am currently working on a multi-fx device with a custom hardware design based on the Daisy Seed. I’m still on the breadboard & mostly doing coding for the firmware which is coming along nicely.

Unfortunately I am having problems getting line levels into the Seed and also getting line levels out of the Seed. For my testing routine I am sending a 80Hz sinewave at -0.1dBfs out of Ableton Live trough a line output of my audio interface & finally into the left audio input of the Seed. For testing, I loaded a simple passthrough patch onto the Seed. When I compare the signal I am sending into the Seed with the signal I am getting out of the Seed with an oscilloscope plugin in Ableton Live, the signal is clearly clipping.

It stops clipping when I attenuate the signal going into the Seed by roughly -14dB. Now the signal that’s coming back into Live from the Seed is pretty quiet, obviously. I then need to amplify that incoming signal by roughly 20dB to get it back to the level the sinewave had from the very beginning (before the attenuation).

What am I missing here? I feel like the problem must be at my end cuz I’ve read multiple times that the inputs & outputs of the Daisy Seed are line-level.

Any help would be much appreciated!
Louis

2

Hi I can’t answer directly, but as this mkght interest others, Ijust tested this with a function generator and an oscilloscope. If I input a sine with 1 VRMS I get exactly 1VRMS out, this results in floating point values within the range of -1.0 to +1.0.

But professional line level is +4dBU (or ca. 1.273 VRMS or 3.6 Volts peak-to-peak). The datasheet says this is the maximum level for the inputs, but for the outputs it specifies 1VRMS at a digital maximum level of 0dBFS. I am unsure whether this means values above 0dBFS or ±1.0 are hard clipped at the output as it is in the column “typical”, but this could be tested easily by generating high values on the daisy and see what comes out.

This would however still not explain your needed 14dB of attenuation to avoid clipping. Do you have a multimeter with AC/RMS measuring capabilities? That would be a good start to verify your audio interface is actually running at the expected levels (Note that the RMS measurement only outputs useful readings with sine waves tho). Of course you will have to get into the weeds with all these conversions between Volts RMS, Volts peak-to-peak, dBU and how that maps to the digital dBFS scale, but hey.