Sound Skulptor forums

Build help and troubleshooting => MC624 Monitor Controller => Topic started by: audiosoldering on February 11, 2025, 11:04:34 AM

Title: No function of -12db over inputs ans outputs
Post by: audiosoldering on February 11, 2025, 11:04:34 AM

Finished the build and everything sounds great.  I'm just having two issue. 

The attenuation of inputs and outputs.  I can add +12db of gain on all i/o but I don't get any attenuation.  Also at -63 I have level louder than I would expect. 

The relays are not clicking,  Which relays and IC deal with the i/p and o/p attenuation? 

thanks

Title: Re: No function of -12db over inputs ans outputs
Post by: JPK on February 12, 2025, 12:07:32 PM

I can add +12db of gain on all i/o but I don't get any attenuation.
When you are at -63dB attenuation, it is not possible to add more attenuation. This is normal. The offsets are added to the main level but the main level cannot go above 0dB or below -63dB.

Also at -63 I have level louder than I would expect.
Do you have all the -1dB steps from 0 to -63?

Title: Re: No function of -12db over inputs ans outputs
Post by: audiosoldering on February 12, 2025, 03:53:40 PM

Understood on the attenuation.   

When I run a tone into the input of the MC624 and back into my DAW I observe the following.

-63 on MC624 set to -63db db on daw meter.  A 1db increase is observed until -5.  After this, there are no more level increases or relay clicks. 

Thanks

Title: Re: No function of -12db over inputs ans outputs
Post by: JPK on February 13, 2025, 04:26:11 PM

Check that the in/out offsets are set to 0.
If one input or output is offseted by +5dB the the max level will be reached at -5 on the display.

Title: Re: No function of -12db over inputs ans outputs
Post by: audiosoldering on February 13, 2025, 10:47:55 PM

Thanks for explaining the functions. 

Listening to a loud source, "Mastered Music," I find it to be 14db louder than some of my lowest listening levels when set to the maximum attenuation of -63. 

If I pull my DAW fader down an additional 42db then the signal is inaudible.  

Title: Re: No function of -12db over inputs ans outputs
Post by: JPK on February 14, 2025, 11:39:13 AM

To check that the unit is working do the following:
1. 
- send a low level audio signal (preferably a constant sine wave) to the input,
- set the level of the MC624 at 0dB, note the audio volume.
- bypass the MC624 completely and check that you get the same audio level.
2.
- send a strong audio signal (preferably a constant sine wave) to the input,
- set the level of the MC624 at -63dB, note the audio volume.
- Lower the audio signal by -63dB at the source,
- increase the level of the MC624 to 0dB and check that you get the same audio level than before.

Title: Re: No function of -12db over inputs ans outputs
Post by: audiosoldering on February 14, 2025, 04:24:00 PM

Thanks for the test method.  We are a db between in and out.  I'm sure lowest attenuation will be fine for mixing.  Could it be possible to add an additional Pad if needed.

Title: Re: No function of -12db over inputs ans outputs
Post by: JPK on February 16, 2025, 05:42:22 PM

Your amp has no volume control?
If not, you can place 2 attenuators between the MC624 and the amps.

Title: Re: No function of -12db over inputs ans outputs
Post by: audiosoldering on February 17, 2025, 10:42:32 AM

My studio amps never have volume control.  Quad 405, Bryston B4, and my Hypex, I always use the monitor controller for level control 

Thanks, nice clean sounding unit.