Room correction room system vs ears….

@lemonhaze : great post! And spot on.

 

Those who think they can fix their room with some Roon EQ and able to get "perfectly flat frequency response" are just fooling themselves. 

@lemonhaze

OK, some good advice here. All rooms need treatment, it is paramount for good sound. EQ/DSP may help after getting the room sorted out. The problem with room correction electronics is they can’t reduce the overly long decay of sound in an untreated room, how can they? They also can do nothing about the full nulls created when low frequencies recombine out of phase. It does not matter how much power you pump into the speakers the sound will just cancel with the same power. Partial nulls can be boosted but if you try and correct for example a 15dB dip you will not have enough power. It requires a doubling of power to achieve a 3dB boost. Try doubling your amp’s power 5 times!

That’s what Krell is for: you too can break your speakers.

When sound is left to decay naturally in a small space (the average room) detail is obscured by the confused and smeared sound. So determine the required time it takes for your sound to decay by 60dB across the full spectrum, known as RT60 or T60. The average room needs T60 to be about 300 to 400ms.

RT60 (and T60) is somewhat ambiguously named. The 60 dB decay thing is the original Sabine equation. T60/T30/T20 are methods of measuring the decay time (they all return the same result, the lower numbers just extrapolate from a smaller drop in level).

Typically mixing rooms have a lower decay envelope and preference for a listening room will depend on music preference. I like electronic and studio-assembled stuff so I’ve no use for added warmth or envelopment from longer decay times (which benefit classical, for example) so my room is closer to a mix room, around 200 ms. Regardless of preference you also want consistent decay across the frequency spectrum (there’ll be an increase in the lowest octaves).

The thing to do is download a great free program REW and measure your room. You will need to buy an inexpensive mic. for the job. This can provide a CSD plot of your room showing the peaks and nulls. Yes, you will need bass traps. REW can help you best position your speakers and show the effect subs have on the performance.

Smaller rooms (most people’s listening rooms) complicate things a bit as decay to a uniform diffuse field doesn’t happen and RT60 isn’t super-accurate, so listen and judge accordingly. REW has a new method for smaller rooms, so try that.

Multi -subs can and should be used to smooth out the bass response. The optimum would be to treat the room in combination with 2 or 3 subs and you will get to hear, probably for the first time, the music info that has been ’black-holed’ by the nulls. Some who have heard of multi-subs envisage thunderous bass but properly placed and dialed in they enhance the entire spectrum from top to bottom. Think of them as tuning units.

WARNING: place a cushion between your feet in case your Jaw hits the floor 😁

Careful positioning of full-range stereo speakers to minimise nulls followed by judicious EQ to tame peaks at the listening position will often work (or it does for me, in an open timber house but will depend on your room characteristics, so quite different in a concrete apartment block) and yes the difference is dramatic. I don’t need bass traps specifically (approximation of reverb time rises to ~400 ms in the 31 Hz band which is still fine) but I need to reduce a 15 dB peak at 50 Hz (from the room’s second longitudinal mode) at the listening position. Subs give bass extension for limited-range speakers of course, and two or more subs can be located to give more even bass response over a wider listening area. Setup is more complex in that case.

One of the best articles describing small room acoustics in reasonably simple terms is this one, covering decay and the different frequency ranges (specular, transition and modal) to consider when setting up gear and a room.

No preamp? Dac straight to amp I’m guessing? 

@mesch I am with those recommending to treat the room 1st.  I made my own panels using rockwool 60 in 2x4' sheets 2" thick framed with 1x2" pine and covered with fine burlap fabric.. To start I would place them at the 1st reflection points on side walls, behind speakers and behind the listening chair if the back wall is close. another 1+ regarding room treatment and locating speakers in the room before buying DSP or whatever.

+1 with Mesch regarding building your room treatments on your own. Much less expensive and you build just what is needed for your individual hearing. 

+1 on working on speaker location. Never had a perfect room that fit with a golden triangle, etc. You can google this stuff and it is just a place to start. Would recommend checking out Zu Audio speaker placement. They have a slightly different approach and I thought it helped me. Right now, one of my speakers is within two feet of the side and front walls. The other speaker is further out in the room and actually closer to my listening position. The sound is balanced with a wide soundstage. Small tweaks until it is "perfect". 

Thanks for listening

Dsper 

 

 

 

 

 

 

=-

 

 

 

 

 

 

 

 

 

 

 

 

=+

I've used digital room correction for years, first as a plug-in to Foobar2000, and now with Minidsp's Dirac Live box. I rent and am a fixed-income. The former means I deal with rooms that are sub-optimal, acoustically. The latter restricts how much I can spend. The Dirac Live box corrects both frequency and time domains, and for my application, it's well worth it.

The weakest link in most stereos I've heard has been the room. I'd do room correction before I upgraded anything else, but budgets and rooms vary, so YMMV.