I have the DNA 800 and I found a NA NS 4-10 locally for sale here at a good price BUT it is 8 ohms. Lot I have read was to use a 4ohm cab with this head (BTW I understand all the power fx of 8 vs 4 Ohm) I do not expect to add a second cab, so would the DNA 800 and 8ohm cab work for medium sized club work? (Mostly prog rock not mic'd/DI) Mainly Fender passive and Ric basses used.
Since almost nobody really runs these heads to the max, I think you'll find you have more than enough power with an 8 ohm cab. Yeah, it will be about half of what the amp will put into a 4 ohm cab but it's still 400 watts. That's more than enough for a medium size club. Plus, you can always add another 8 ohm cab to it to give you the extra power and more speaker coverage.
A lot of "how loud" depends upon the sensitivity of your cabs too. I used to gig through a 410+115 stack. The 410 in that stack had a sensitivity of 92 db at 1-watt at 1-meter distance (2.83V@1W/1M). That means 1 watt would produce 92 db at 1 meter distance. That is NOT an efficient cab. The formula goes that you need to double the power to get a 3db increase in sound. Although 3db is technically twice as loud, the human ear hears a 10db change as twice as loud. Here's a quick chart showing you the progression presuming everything is working perfectly (example is from an acoustic B410 cab that will handle 400-watts - newer ones handle 600-watts rms):
1 watt 92 db
2 watts 95 db
4 watts 98 db
8 watts 101 db
16 watts 103 db
32 watts 106 db
64 watts 109 db
128 watts 112 db
256 watts 115 db max on this cab is about 116db with power handling of 400-watts rms.
512 watts 118 db
1024 watts 121 db
120 db is a loud rock concert and pain begins at 125 db.
Now, by comparison my DNS410 cab has a sensitivity rating of 106db. So 106 db is where "barely on" starts whereas the other cab requires 32-watts to get there. Here's a chart showing how that progresses (again presuming everything is perfect) with the DNS410:
1 watt 106 db
2 watts 109 db
4 watts 112 db
8 watts 115 db
16 watts 118 db
32 watts 121 db already louder than my other cab's maximum
64 watts 124 db
128 watts 127 db
256 watts 130 db
512 watts 133 db
1024 watts 136 db
1400 watts 137 db -137db is the max rms power this cab will safely handle. Ohterwise 2048 watts would get it to 139.
So the DNS410 will be as loud using 1-watt as my acoustic B410 is using 32 watts. Using 32-watts with my DNS410 will produce 121db and would require 1024 watts on the other cab IF the other cab could handle it. So sensitivity has a LOT to do with how loud your watts convert to. I gigged for years using that acoustic B410 with a GK-115BLX underneath it. Adding the 115 got me about 2db more and I was supplying a maximum of 240-watts to each cab (each was in its own channel). I typically ran the master up around 10 to 11 o'clock depending upon the size of the room. So I wasn't pushing near the limit of power to those cabs. This even worked fine for outdoors too. So all told, I was sending a total of less than 400-watts to those cabs.
Now using that same amp with my DNS410, I run it bridged with 800-watts available. I rarely run the master above 9:30 because it's just too loud. The sensitivity of the cab has a lot to do with how loud you can get but really, 800-watts even with a low sensitivity cab is plenty. It will be MORE than loud enough for a medium size club.
