Hi Guys

I have a lynx Hilo unit connected to a SPL Masterbay S and returning to the Lynx Hilo unit through a pair of Prism Overkiller Barrels.

I believe the input on the SPL Masterbay S is configured at +4dbu. Therefore I am setting the output trim to +4dbu on my Lynx Hilo unit feeding the SPL Masterbay S.

The output of the Masterbay S is connected to the Prism OverKiller Barrels which are configured to +18dbu which are then connected to the Lynx Hilo unit input. Therefore I have set the input trim on the Lynx Hilo to match the Prism Barrels at +18dbu.

When sending a test signal through the chain using these settings the returned signal is somewhat lower than unity gain. If push the output fader to max on the SPL Masterbay so that Prism Barrels are limiting the signal I would have thought the returned signal would be pushing the 0db mark on my DAW but the signal is somewhat lower.

I was always under the impression the input output trims on an AD DA converter should be set to the kit it's feeding and being returned from.

Am I just being dumb here? any advise would be much appreciated.

Can you specify what you exactly mean with "somewhat lower"?
I took a look at the Lynx Hilo manual and I couldn'd find a +4dBu output trim setting that you mention.

I'm under the impression that the in-/output trim levels on the Lynx are not the operating levels, but the max i/o levels, which make more sense (+18dBu, +20dBu, +22dBu, +24dBu).
If so, it means that depending on the amount of headroom you desire, you can set the trims to +18/+20/+22/+24dBu.
Assuming that your soundcard/DAW operates at +24dBu max input (this means that '0'dBFS = +24dBu), you should set, at least, the output trim of the Hilo to +24dBu.

But since you'll be limiting your signal at +18dBu with the Prism Overkillers, I expect your signal to hit at around -6dBFS in your DAW anyway (18dBu = 6dB lower than 24dBu/0dBFS).

I hope this helps.

Success.

Great stuff and thanks for taking the time out to reply on this