Hello, I need some basic info about setting up the Dayton DSP-408 between my Marantz DAC\/preamp using the DAC's variable outs (for final system volume control), and my 2 power amps vertically (one amp runs mid\/highs and other runs low of both speakers, respectively, but it seems to me all channels are the same (fungible) and for this each can be thought of as completely independent, so in this case vertical = horizontal, i.e. I can also run one amp per speaker, one channel to mid-hi the other to low, and same with other amp for the other speaker, it is a "same-difference", horizontal versus vertical setups with identical amps in a biwired 2 way system degnerate to equivalence, as if there were always just 4 physically separate mono amps, 2 channels filtered to the highs, 2 channels to the mid-lows, just don't accidentally port the signal thru the right filter for the wrong drivers with their passive networks disabled, poof go my tweeters). \n\nMy speakers, 40 year old Snell Type A's, no's 705 and 706!!!, were apparently the first speaker model ever designed to be vertically bi-amped, which I plan to do later with a Dynaco ST-70 (original refurbished) and one of my NAD C270's (other amp is a C370, same power stage, integrated preamp bypassed, although I can run my DAC in fixed output mode too, and use the NAD 370's preamp instead, but this doesn't change my configuration or questions really, it is simply something I could try to see if it makes my sound different, errr, I mean BETTER, lol). \n\nNow, I have no issues with setting up the routing and crossovers and physical cables, and largely want to get this active biamping going in a flat (EQ off) and minimally ideal gain configuration, just for proof of concept in terms of hearing the expected improvements, before I dare to use 2 different amps (here I might pay someone to help with gain matching and tuning). I do still need to actively prefilter both a low pass on the 2 woofer output channels and also a hi-pass for the 2 mid-high outs (and have the numbers recommended by Snell to do so). \n\nAlso, as recommended by Snell, I am only disabling\/bypassing (with provided shorting plugs) the woofer filter network to start (just a bass driver, not a sub, but 10 inches and downfiring, nominal by-pass point for this 2 way to 3 driver set up is 275 Hz, with a 4 times overlap correction factor, I am instructed to set the hi pass to 69Hz, the low pass to 1100 Hz, again as per the manual for these speakers when biamped). This, at the very least, gives me the 3dB bass channel gain improvement and should improve bass noticeably all by itself. I did try with a used analog crossover first, but it or the XLR to RCA adapters had issues, the crossover ate all the bass power somewhere (it cut in and out when changing the volume from the DAC\/preamp, and I had to go higher, not lower volume, the opposite of what was expected), but the mids and highs did sound more transparent, so that was encouraging). Unless I am sure the settings on my DSP match those of Snell's hard to find custom active crossover (so the question is whether the specs in the doc are also what the custom active crossover is physically set too, or are these settings just meant for 3rd party active crossovers, this remains ambiguous???). \n\nSo, I am clearly advised to keep the mid-hi passive network active (I am trying to buy the custom one used, there is one out there, but I haven't heard back from the seller, using this I can bypass both filter networks without using a DSP, somehow, not sure why I can't with a DSP set with the same hi and low pass 2 way values??? I am guessing the tweeter has something that can't be bypassed in front of it for meshing with the custom active crossover in place and the passive mid-hi network bypassed, but it is very hard to find that info now). So be it. \n\nMy issues start with trying to understand how to set all the (3 levels of) volume control, both on the 4 output channels, on my DAC\/Preamp to set the DSP up, and finally on the master volume in the app. I have no standard external gain adjustments on my NAD's as car amps have, they are fully on power amps (the 370 does have a variable RCA input too, but not the 270).\n\nSo FIRST: I am unclear if my preamp or the DSP app ends up controlling the final listening volume, and SECOND I am looking for some way to set all these controls to some standard sort of ideal defaults (output channels at full, master app volume at 0 dB???), i.e. minimally configure the DSP just enough so I can safely connect my speakers and make small real-time adjustments with actual music instead (try different filters, slopes, slightly tweak the filter frequency settings, etc.). This is where I am stumped. Do I really need extra testing equipment here, I have a tone and pink noise generator on my PC, and given my amps are identical should have no need to gain match, EQ, or adjust delays, just set the overall system to some flattened and safe ideal to start, so I can finally connect my speakers safely and do minor tweaks from there. Thanks! Brian.