TOPIC:

I am getting a little distortion in a couple of tracks at certain frequencies, have I somehow caused this through the calibration process?

Take the DDRC out of circuit and see if there is still a problem?

Do you possibly have DDRC's master volume at 0 dB? Dirac can add up to 10dB boosts so you need to consider digital headroom for this, especially with digital sources where they music signal can reach the 0 dBFS level. 

No distortion without dirac running.

Ultrasonic wrote:

Do you possibly have DDRC's master volume at 0 dB? Dirac can add up to 10dB boosts so you need to consider digital headroom for this, especially with digital sources where they music signal can reach the 0 dBFS level. 

 

I do have the volume output at 0db, I will lower this when I get home at the weekend. 

Whether having the master volume at 0db is a problem or not will depend on how you are controlling the overall volume. If you are feeding potentially 0dBFS signals into the DDRC, and controlling the volume downstream of the DDRC, then as Ultrasound has said, there is a potential headroom problem because Dirac can (does) boost some parts of the signal. If (like me) you are controlling the overall volume upstream of the miniDSP (I feed signals from streamers into my miniDSPs and control the volume via the streamers) and are therefore feeding signals into the DSP that are well below 0dBFS, then the Dirac boost won't be an issue unless you like to crank the volume up to 11.

Tony_J wrote:

Whether having the master volume at 0db is a problem or not will depend on how you are controlling the overall volume. If you are feeding potentially 0dBFS signals into the DDRC, and controlling the volume downstream of the DDRC, then as Ultrasound has said, there is a potential headroom problem because Dirac can (does) boost some parts of the signal. If (like me) you are controlling the overall volume upstream of the miniDSP (I feed signals from streamers into my miniDSPs and control the volume via the streamers) and are therefore feeding signals into the DSP that are well below 0dBFS, then the Dirac boost won't be an issue unless you like to crank the volume up to 11.
 

I feed the signal from my streamer via optical into the minidsp then from the minidsp optical into the Audiolab 6000a DAC, so unsure if this could be causing distortion?
 

Which device in the chain do you use for volume control? Streamer, miniDSP, or amplifier?

If you control volume using your amp, then turn the Master Volume on the miniDSP down by 10dB (i.e., set it to -10) and run your test tracks again.

I didnt get a chance to try it last weekend, but I have another question possibly related to the distortion, when I originally took the speaker sound sweep the replay volume was too low, so I changed the minidsp volume to 0 and raised the mic level from -10 to 0, would this cause distortion?
sorry I am new to this:(

Gazza1101 wrote:

I didnt get a chance to try it last weekend, but I have another question possibly related to the distortion, when I originally took the speaker sound sweep the replay volume was too low, so I changed the minidsp volume to 0 and raised the mic level from -10 to 0, would this cause distortion?
sorry I am new to this:(

I'm fairly certain you'll find reducing the master volume setting on your miniDSP will fix your problem. What you've experienced is basically expected behaviour that is warned against in the miniDSP manuals for both the 22D (page 23) and Dirac Live (page 51). I'd stop spending time worrying about this until you've tried what is very likely the solution. 
 

Yes, good advice, will check this weekend