Thank you for your interesting observation and contribution.
But I didn’t understand.
Do you mean that a 300 is not enough?
What do you mean with “very strong destructive mode at around 60-70Hz”?
Also about your observation on 4 ohms: do you think 8 ohms are better for a 300?
Should the PMC Fact 8 on paper less expensive speakers be better than the Proac D48R?
In free field, the sound pressure falls off with distance by an inverse-square law. There are many calculators online, they give approx 9 dB less by going from 1 to 3 meters. As dBs are logarithmic, this is roughly half subjective volume. However, in a closed room the fall-off will be less as much of the sound is reflected and hence the same for different distances from speaker.
I already have an SVS Sb13-ULTRA which I sometimes also switch on for the hi-fi with a different setting than the one I use for the Denon amplifier for the video projector 100 inches.
It is also controlled by an Antimode II.
But I wanted to try to find a pair of speakers that are an upgrade of the Proac D48R in the price class up to 15,000 euros regardless of the help that a well-integrated subwoofer can give.
So a value of 80-86 db at 3 meters (with 252 at 12 o’ clock) in my case is normal and not abnormal
I don’t know, aristoweb. However sometimes it’s just a matter of a surprisingly good match, to room and gear. Someone on another thread here has them and loves them with Naim, so I thought I’d suggest them.
My ol’ professionally refurbished Kef R107’s sound very good, and I believe I’d have to pay a lot to beat them, and they’re probably only worth a few grand. I will be trying the active route in the future to try to improve on them, although probably with a pair of speakers that lend themselves to an active setup.
It seems low to me because, as mentioned, I get similar values at 9-10 o’ clock with 3 meters distance in my room. My speakers have 89 dB/1m/1W sensitivity and my room is also similar in volume, a bit smaller but higher ceiling. (With NDX2/252/300). I never dared to go to 12, as 10 alarms the neighbors and anything clearly above 10 is way too loud for myself (and I am a Swans and Sonic Youth fan, so not afraid of volume 
). I am sure that I would get much more than 80-86, provided that my speakers would not explode.
But like I wrote, phone apps on different phones are not very comparable
I can not compare with the Proacs. Never heard them let alone owned them. My SF’s match very well with the 300. No problem there. But that’s just me,others may disagree.
And like I said,my room is big too,76 m2. And the 300 has absolutely no problem with it. And I am sitting also about 3m away from the speakers. And speakers are also 3 m apart. But I live in an appartment so can not play very loud. That’s why I upgraded from 250 to 300. Much more detail on moderate sound level. 250 was up to the job too btw. Same room same speakers. SF Olympica.
And btw,I also have a calibrated dB meter and that says about 85-90 dBa with volume at 9 oclock. If I would try 12 I think my neighbour would be at the door banging and eventually also kicking it in because now way I would hear him banging at the door.
See below. Something seems to be very wrong. Time for a call to your friendly Naim dealer.
Best, BF
It may not help, but I used to have my SN2 in our lounge, which is a similar size to your room, and it had no problems driving Totem Forest Sigs to about 11:00 on the dial.
I do not understand
PeterR explained above [quote=“PeterR, post:55, topic:15673”]
. You have a very strong destructive mode at around 60-70Hz, and I do wonder if this is exacerbated by a Nap 300 driving a 4 ohm speaker at a high listening level resulting in simply loosing control of the speakers bass drivers. So many variables as always… Good luck Peter 
[/quote]
Not sure that this is a problem. From https://www.naimaudio.com/product/nap-300:
The NAP 300 delivers 90W per channel into 8 ohms and is capable of prolonged output into 2 ohms with no discernible impact on performance. The result is both superior purity of tone and immense power.
In another discussion about this 2 Ohms limit I asked Richard about it, and he confirmed that what it states is indeed the case.
But I agree that something is odd if the 80-86 dB at 12 o’ clock are a somewhat correct measurement on this particular phone
You should post these comments to the OP , which is PeterR. Personally I have no idea of what is wrong.
A picture of the system could help. We should remember that the room is 56 m2, which is very big. And without seeing how is the set up and where are the speakers and listening position, it’s hard to discuss.
I know, I didn’t quickly find the original post because your link was broken Whoever said it, it was just my input on this as I know that line from the manual and discussed it with Richard in the past.
Nobody knows what is wrong, we are all guessing, but something seems odd. Agreed that a picture may help, but I hope you won’t get into hot water again for suggesting it 
I will post the pics later no problem
This is my listening environment.
On the left side of the wall there is a large sound-absorbing painting (New York) and usually when I listen to the curtain it covers the glass.
On the ceiling there are various absorbent / reflective panels and behind the speakers there are two large bass traps with reflective bars: one in correspondence with the left corner and the other behind the right speaker for uniformity.
The phono stage for the Vprime 21 is the 2-module TeddyPardo with separate power supply.
There are linear power supplies for routers, Lan Switches, NAS with Audioquest cables.
My listening position is the center of the red sofa.
I hope the numerous photos do not bother you.
I preferred to take every angle to give awareness of my listening environment.
Breathtakingly beautiful and no reason why it should not work! Looks bigger than I thought, and there is the added volume of the staircase as well. Could you kindly tell us the measurements again please?
In any case, from the pictures it looks like a lot of volume, maybe that’s the simple reason for the dB measurement. As everything works fine at normal volume, I still believe you are asking for too much from conventional-design hifi speakers at 12 o’ clock, and I do not believe that the 300 is the main problem - even with more power, I don’t think the speakers could take it. If I had the desire for this and no neighbors, I would still look at a suitable speaker design - which might possibly need more power but maybe not. (Horns wouldn’t)
Beautiful room and system!
I see that the speakers have not enough space around them, they are constrained , they can’t breathe and open themselves.
I would place them at minimum 50 cm distance of the rear elements, so closer to the siting place. Just to try first, even if the WAF will be higher.
Some pics show the right set up:
On the short wall in my 16
x 25-foot listening room, a wide sweet spot is achieved with the speakers about 8 feet out in the room and four feet from the wall, with my listening chair 11 feet from center soundstage. The ribbon generates enough HF energy to not require any toe-in in an un- treated or slightly live room, but in my listening room with GIK absorp- tion panels at first reflection points, three degrees of toe-in made for the best balance overall.
The two 6 1⁄2 inch woofers pro- vide plenty of heft, possessing no upper mid bass hangover, bloat or other anomalies, mating perfectly to the ribbon tweeter. (continued)
ttom
ProAc lists the LF frequency limit at 20Hz, but without a +/-dB qualifier. In a 16 x 24-foot room this proves ever so slightly ambitious, but test tones reveal solid output at 30Hz diminishing rapidly after this. Real-world music listening proves that unless you
are listening to a consistent diet of EDM tracks, you’ll never need a sub, as the D48Rs offer plenty of low frequency oomph. Whether listening to the heartbeat at the beginning of Dark Side or your favorite Dr. Dre cuts, these speakers deliver.
Because the pair of 6 1/2-inch woofers are so fast, those not familiar with these speakers might misinterpret the lack of mid bass bloat for lack of output. A nearby pair of vintage JBLs appeared to have a warmer, fuller bass response until we started playing tracks with real bass information. Immediately the tables were turned in favor of the D48Rs, with impressive results. (continued)
FROM TONE AUDIO MAGAZINE
