Have you tried the Tap Tempo feature? It's new in the T4S/T8S and it let's you set the tempo for delay by tapping the center button in the delay settings. The T1 didn't have this feature.
A friend asked me why he couldn't tap in anything slower than around 125 BPM (Beats Per Minute).
Here's the answer
The maximum delay is 500 milliseconds. This is 120 BPM (Beats Per Minute). If you tap anything slower than that, it won't register. If you are working at a tempo slower than 120 BPM, try tapping eighth notes.
I just spoke with two Bose technical support people one from Pro-Sumer and one from Pro-Audio and neither was able to answer my question.
For as long back as the very first outboard digital delays by DBX and Lexicon, the Tap Tempo feature has been around. The most musical way to use delay in a sole or ensemble /band setting is to have the delay setting shared by all tracks that are using delay. Same holds true for reverb, that way the instruments and vocalists don't appear to be in different spaces (rooms). In most mixers including digital, reverb and/or delay can be routed from an effects or aux bus, so that the same settings apply to all channels in varying amounts based on the channel's effects or aux send. Industry standard stuff, right.
Well for reverb on the TS8, Aux 1 can be used. So you assign a nice reverb for each Scene to Aux 1 and you're good to go. Same should be true for Delay. Maybe you want to have delay on the effects bus Pre-Reverb, Post-Reverb or in parallel each creating different ambiences. A single delay setting shared by all channels that require some delay. Then the Tap Tempo can be used as described to set the delay to a quarter note, quarter triplet, eighth note, eighth triplet, and so on. Anyone who has done live sound for any length of time has used this technique at one time or another.
Unfortunately, this is not achievable using the T4S or T8S. There is not a delay effect available on Aux 1, only reverb. There appears to be no way of routing each channel through a bus to a global delay where the same delay tempo can be shared across multiple tracks.
This is such a common technique in live sound reinforcement, that I am dumfounded that the Bose engineers who designed the T4S and T8S could have missed the boat on this one! There are SO Many digital mixers where this common signal routing is available in a small form factor mixer including:
Allen & Heath (All)
Behringer X Air
Please let me know if there is a workaround for this. Tap Tempo is a must for any mixed that I purchase and a deal-breaker if this effects routing flexibility doesn't exist on the T8S.