Total bass suck out at 40hz

So I'm a little slow, but it occured to me today to see if there were test tones recordings on Tidal of Qobuz. Yes there are. I have a radio shack SPL meter so I went to work playing them to see what I had in my room. I was shocked to find a total lack of audible bass at 40hz. At first I thought they must have made an error in the recording. Then I went to a different set of test tones and wow same thing. I never dreamed something like that would take place. I have read a lot of discussions about bass peaks and nulls and always thought it would just be slightly less in volume at the null, not completely gone. So Am I imagining this and if not what do I do to remedy it. I am apparently missing a lot of music and never knew it. I am currently listening to my freshly refinished Yamaha NS 1000m speakers(just put them in the system Wednesday after work) with a Modwright KWI 200 integrated amp and a Lumin streamer/dac. I also have stereo Rythmik  F12 subs. Thanks, Allen.
I've had some pretty nice systems throughout my lifetime.  When COVID struck and I had some time at home I decided to get a digital sound processor.  I fiddled for weeks and tri-amped my speakers with a relatively cheap Rotel 6 channel SS amp.  I got a microphone and some software to record the frequency response.  WOW, what a learning experience!  There were a lot of peaks and valleys in the frequency response.  I did some correction with the DSP, and did a time delay to align the speaker drivers.  Adjusted the location of speakers in the room, and did some room treatment.  The results were incredible.  This is the best sounding system I've ever had.  And I can still tweak it to sound better.

Before you spend $2K on those speaker cables, think about measuring your frequency response and making adjustments to get it flatter.
Three cheers for rvnye2! Isn't that something? People just do not realize what happens to an anechoically flat loudspeaker when you put it in a room. Millercarbon would vomit if he could see how his system measured. Actually everyone would. +- 10 dB peaks and valleys is par for the course. That is twice or half as loud! Whatever you think the degradation in your signal might be converting it to 24/192 digital the improvement made by digitally equalizing and timing your system drastically out weights it. You see this comment time and time again in reviews of the best room control units over the years. It reminds me of when cycling was moving from manual to syncro shifting back in the late 80s. "Real cyclists don't need syncro!"

When I figure out how to photograph my computer I will display measurements of ESLs in a 16 X 30 X 8 foot room along with pictures of the system.
A little bit of an update, I added a fourth sub to the room. I now have very audible bass from approximately 26 hz up. The fourth sub was not as big a jump as going from two to three but it is an improvement. I now a a slight peak at 40 hz instead of no sound at all but overall the results are vastly better than what I had before. Thanks, to all who chimed in with actual advise, Allen (Mizike).
Good work! If you play with the phase of the rear (or side) subs you might be able to kill that slight 40Hz peak too.