That lovely PRAT

I’m no expert with regards to subwoofer integration, but certainly have been playing with them since the early nineties- and learned over the decades that follow that mains sans sub is a much more coherant system sound.

Until I played with REEQ and things like XT32 (with multiple subs) and Anthem ARC…

ARC is a cut above, but XT vs XT32 can come down to ‘number of subs’…

Top to the tree room re-eq stuff (eg Lyndorf etc) is out of my price point, but certainly going beyond making a frequency sweep smooth, and having setups that can ‘remove room factors’ from the playback- is incredible.

I put the Anthem ARC capable setup into the den to see if loosing preamp quality (absolute) and ADCing my DAC were worthy sacrifices on the path to ‘better audio’

yes and no…

lost a lot of fidelity from one point of view, and gained a stable reference (that was a lot less motivating to listen to, even though it sounded technically brilliant).

My often recommended trick is to ‘steal’ (borrow) the re-requalising surround processor from the lounge room and to briefly install it in the ‘den setup’ (hifi rig)…

Using the rendered graphs generated after a room measure - I can adjust speaker positioning and ‘levels’ using the visual feedback VERY EASILY.

Once I have the speakers and sub integrated to the best they can do -sans modifiying the audio signal- then I consider that the baseline setup for the room… (those playing with REW software would be asking a LOT LESS from it to achieve its’ goal-)

Sometimes it is amazing how much a ‘rear ported’ speaker can alter its lower frequencies with a little extra distance from the wall (happens with toe in, too),…

A room read and reset the speakers will never equate to phase/timing adjusted THROUGH THE FULL FREQ RANGE that modern front end processors can achieve…

but can massively lower the the fatigue- but of itself will not reveal second reflections and ‘brightning’ of sound though unoptimised room layout structure.

Some of the best installs I have ever had the fortune to listen to have been ‘pure math’ affairs, having been designed on paper (calculating reflections/decay) and are brilliant.

A lot of the math, once we digest it, is straightforward.

Our ears need around a metre of space (timing difference) between reflection ‘layers’.

The second harmonics I hear from the side walls are not time aligned with the ones from the ceiling.
Having my chair forward of the rear wall at least ‘half a metre’ (factoring bounce is greater than a metre), adds another ‘clarifiying’ harmonic…

They clarify the sound if the brain can isolate and identify them… they need to be 1m+ further away…

Once we see a room as a number of surfaces and distances to ‘play with’ this can be quite fun…

And is generally a ‘set and forget’ aspect to hifi setup (work done once and then ‘many years of enjoyment’)

I use Vanessa Maes Butterfly lovers concherto (or whatever name is ‘similar’) for toe in changes as the stage in this piece of music (first track) is so ‘back’ and room reflections really can muddy or clarify this stage setup.

I spent many many hours ONCE listening to the stage change with a few millimetres ‘more’ toe in (/‘less’ toe in)… could change the depth of the stage beyond my rear wall, and with that imaging change, comes a sense of perception as to how wide the stage is etc… when toe in changes the stage dimensions so noticably… reaffirms the value of ‘why we need to set this’.

It is better as a two person task/‘panel’, so long as the testers can be fully relaxed (and have the time) to do the due dilligence…

TL: DR - I love to cheat; and use surround amps in my hifi setup to ‘check the room’/‘speaker and subwoofer integration’ and adjust using the visualised graphs that the room test/calibrate function of modern surround processors allows.

Toe in is best done by listening to a familiar track (and maybe using notes to record findings and tape on ground to take note of the positions)

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It’s just incredible, I’ve had my SN3 for 2 years now and there’s no doubt in my mind I can never go with anything other the Naim now… I’m hooked :beers:


Same here. It’s just very very special

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But do remember as far as bass extension and port performance goes where the speaker is ported, front, rear or underneath has no bearing on performance, the only requirement on distance to a boundary is that it is equal or greater than the diameter of the port. Other considerations rather than port itself will govern how close or far from boundaries the speaker performs well at. At lower frequencies, and physically smaller speakers as used in most hifi setups radiation from a speaker is all around, not just front facing.
One consideration on port placement, and is dependent on speaker design, is the extent of frequency leakage through the port such as mids, which is why some designs prefer rear or especially underneath ports, so this leakage doesn’t interfere as much with the heard audio.

Absolutely, here the speaker tweeter and baffle design can help out with a more directional dispersion, perhaps especially in the Y axis from the tweeter. Tweeters tend to be more directional anyway


I might be wrong here but don’t speakers go towards this? There’s talk about Naim being all about PRAT but speakers play a vital role and they don’t all sound great with Naim.

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Indeed, for so called PR&T speakers are essential to bring out the pace rhythm and timing… the electronics certainly can’t do it on its own… there needs to be a synergy.
I can’t think how a speaker can’t sound appealing specifically with Naim in its own way… (it’s not all about PRAT) unless the speaker’s performance is simply not your cup of tea.


I had heard of PRT but didn’t actually hear it until I heard a CD5. It was one of those light bulb moments. What I was actually hearing was just a hint of what was possible, but I remember it well because it marked the beginning of my transition from listening to my Hi Fi to listening to my music.

Some years later I heard a prototype Naim streamer playing into 552/500/SL2/nSub. That was when I fully understood what all the fuss was about, particularly timing. Musical memory is fallible but it’s easy to remember how you felt when something grabbed you. That afternoon was memorable.


Thank you.
We’ve been saying that for years (and there’s nothing magical about vented - i.e. ported transmission lines either!).

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For us it’s simple:

Involvement in the music: we find this with Naim systems more than we do with most other systems.

Describe it how you like, but for us it’s about getting “pulled into the music”.


Naim PRAT usually (but not ALWAYS) comes from relatively simple, but very low-impedence and quick to respond power supplies.

If you ever heard a NAC32/NAP160 combination you will know exactly what I am talking about.

The relatively crude, but very responsive cursory PS built in to the 160 gave a tremendous sense of pace and dynamical tracking.

Simiarly the relatively crude PS of the NAP110 sounded ‘faster’ then the NAP140, inspite of the latter having a for more robust PS.

The Naim sound is sort of like stripping down your hotrod for maximum acceleration for mininimum torque. This is done by cuttting out all deadwood, even at the expense of occasionally useful deadwood.

By sacrificing absolute control for response speed, you got an exciting leading edge propulsion that was quite captivating, yet at the same time seemed to be anabolically enhanced.

Which is why a 32/110, or especially a 12/120 can render most modern amps dull and uninspiring.


I choked on my cup of tea literally when I read that… a bit of a gross generalisation I think. I can think of many quality modern amps that are exciting inspiring and / or exhibit PRAT with the appropriate speakers and source. (Sugden, DNM, Densen to name a few I personally believe provide great PRAT in addition to Naim)

PRAT is largely about timing and accurate dynamics. Timing is significantly about a good consistent phase response.

Powersupply regulation is a double edged sword and there are pros and cons. The less regulation the more you will likely require negative feedback to adjust the gain of the amp under load.

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Nice description Ron.

I also felt that sometimes the CB 32.5/160 took things a bit too far and was all about rhythmic drive and not enough of everything else, and probably why I prefer the 42.5/110 or the more laid back BD 12/160.

Speakers of that era could also make the situation you describe a little better or worse, but never enough to change my preferences.