Sopra 2 Bass

The MA9000 is more than enough. Don’t let people tell you different. McIntosh is the red headed step child on this forum but their current line is excellent agents pretty much anything. The Mac is a great combo with Focal. The Sopras dips to 3 ohms at 100hz so try the 2 ohm tap. That amp will put out 300 watts at 2 ohms and you are only going to use 4-5 watts. The drive units in this focal will burst into smoke before that amp runs out of gas. For what it is worth I run a mc462 with speakers that are well into 2 ohms with good results.

Anyway the Sopra does not put out low bass without room gain. Just the way it is and most speakers are the same way. I am of the opinion that all but the largest (and I do mean largest) speakers need subs.

I would buy two subs and highpass them at 60hz (where the drivers take a dive and rely on the port). I have used JL subs with the focal electrica line before with good results.

A highpass crossover is the key to good integration. Just running them under your speakers without a highpass will result in poor integration most of the time. If you use something like a JL E112 there is a built in highpass. You would run the preamp into the sub then sub into the amp. In your case you would pull the cross bars on the back of your integrated amp and run the output from the #1 out to the sub and then run the sub back into the power amp input. You can then just adjust the crossover to where ever you want and the highpass and timing will be handled in the sub. There are a number of external crossovers too as most subs lack highpass crossovers.
The Sopra 2s with good subs would compete with pretty much anything on the market within sane prices.
Like others have said you can push your speakers toward the front wall. You need to be closer than 41” to not cancel bass below 80hz or more than 6.7’ out from the wall. Anywhere between those two boundaries there will be hills and valleys in the bass.
I personally would pull the speakers out as far as possible and run subs at less than 41” from the front wall. This way each speaker can run with minimized room effects.
Video on the subject.
https://youtu.be/T10_MLGOBfc

Assuming the acoustic center of the Sopra 2 is 18” off the floor (guessing, two woofers + port) then a 7.5’ ceiling would make a dip at 47ish hertz but one you sum in all the other boundaries (floor, front wall, side wall, back wall) it will fill in fine. 

Really the Mac is fine, more than fine. The output transformers don’t work like a tube amp (opposite actually) In tube amps the transformers are used to couple the low impedance of the speaker to high impedance tubes.  
In Mac solid state amps the transformers are use to reduce the load and let the amp put out the same wattage regardless of load.

if you end up with subs it sounds like your Mac has a built in highpass which will open up your sub options. 
There might be amps that give you more bass impact (pass labs probably) but bass smoothness and depth is a function of the room and speaker interaction. Focal’s can get a little edgy in the upper mids and highs and Macs get a little smooth in the upper mids and highs. They are a near perfect match imo. 

The right tap is the one you like best. The impedance curve of the Sopra is pretty wild (but most modern speakers are) so no tap is 100% the best.  
You can gleam some insight into the Sopra 2 by looking at the impedance curve vs frequency (link blow)
Each lower tap is a different contact point in the auto transformer output and as you go lower you cut voltage and bring up the current. It is best to match the load but when the load swings like crazy it can’t really be matched. 

the short version is if you run the 2 ohm tap you get more power where the impedance is low but less power where it is high. With the Sopra being all over the place I am not sure it matters what you choose. 
But really don’t over think it. If it sounded more open on the 8 ohm tap just use it. The Mac has enough power to plow through it anyway. 
On a side note I think crazy impedance curves are why large powerful amplifiers sound better. Not because you need the power (again only using 4-5 watts) but the big amps just freight train right through these impedance curves. Where lower powered amps can really get tripped up over them and get hot and compress. 
https://www.soundstagenetwork.com/index.php?option=com_content&view=article&id=1445:nrc-meas...

Izjjzi,

Interesting information on the different taps. Looking at the impedance graph of the Sopra 2 it looks like the 4ohm tap would be the right one. You want to match the lowest point of the impedance to the tap and the Sopra dips to 3.7-ish around 100hz. 
Going to the 2ohm tap will probably not change the tonal balance (because it is lower than the speakers so it will not add gain to higher impedance sections of the speaker) but it will reduce your power. I would guess by about 1/3rd. This is because you already have enough current and the 2ohm tap will reduce the voltage.  

But really the amp is powerful and runs cool so using the”wrong” tap will not hurt anything if it sounds good to you. 

If you look at stereophile’s measurements of the MC462 (link below) you can get some in-site as to why you want to match the lowest impedance. It will reduce the distortion and still maintain the full 300 watt output. For most speakers the 4ohm tap is the right one. 
“Figs. 6–9 indicate that distortion is extremely low, lying below the noise floor at powers below 30W or so. I therefore plotted how the THD+N changed with frequency from the 8 ohm output at a level of 28.3V, equivalent to 100W into 8 ohms and 200W into 4 ohms, where I could be sure I was looking at distortion rather than noise. The result (fig.10) reveals that the THD into 8 ohms (blue and red traces) and 4 ohms (cyan, magenta) rises above 1kHz, but still remains below 0.007%. I haven't shown the THD+N trace into 2 ohms from this output, because it was >2% in the midrange and treble and >3% in the bass at 28.3V, which is equivalent to 400W into 2 ohms. The moral: Match the MC462's nominal output to the lowest impedance magnitude of the loudspeaker used.”

https://www.stereophile.com/content/mcintosh-laboratory-mc462-power-amplifier-measurements


As for the the popping sound it could have been a driver bottoming out if it was super loud with deep bass. It probably will not break a well designed driver but it will be uneasy for sure. 

 If it was power related the Mac’s power guard lights would have come on (lights up orange like startup) and cuts the power. 

I would buy two subs even if you have to step down to a lower model due to cost. For music you will really not need that large or powerful of a sub. I would also use the highpass function of your McIntosh and 60hz is a good place to start… and probably end basses on the Sopra’s measurements. 

The lack of bass does not surprise me. The speaker’s bass drops like a rock after 50hz and steps down pretty hard even after 100hz (link below). Room gain will be very room dependent. Some rooms might even make it worse not better. 

I think izjjzi should measure the room at the listening chair. Does not have to be anything fancy. Even a DB phone app and a streamed test tone album would give you a good idea of the room. 

https://www.soundstagenetwork.com/index.php?option=com_content&view=article&id=1445:nrc-meas...

You will like the sub it will make a big difference. One sub can sound fine but it is a little harder to work with to get smooth bass. Two subs is much easier to get flat bass in room. But with a single sub you should be able to find a spot that gives you smooth bass for a single seat at least.