So I dont subject drift Thomas’s fab thread as he builds his dedicated listening room. I thought I would start this thread on my journey to make my very not ideal living room sound better…how close can I get? lets see.
So following in the footsteps of so many I have downloaded a copy of the free REW software and purchased a calibrated microphone.
Below you will see a sketch of my room and my initial measurements. I can post more if any experts out there would like to see. To be honest I am suffering data overload already!
I took measurement’s of each speaker alone and then combined. I also then moved the sub around to see how that affected things.
WAY WAY too much bass energy!
LH side of the room seems to generate a nasty spike at 40Hz, made worst when the sub was there, removed when the sub was moved behind the RH speaker.
Significant null around 300hz
Yes, far too much VLF energy with the sub on - in normal phase this is shown in the blue trace and in inverted phase this is shown by the slow decay in the waterfall plot.
The purple trace (without sub! ) is actually a very good response curve in the frequency domain.
The black trace (sub @ inverted phase) is the worst, as it shows a lot of destructive interference in the lower midrange. I suspect this is also the cause of the ragged lower midrange in the waterfall plot.
If you show the waterfall plot for the main speakers only, I suspect it will look a lot better, however I also suspect that it’ll still show that you need more absorption 35 to 90Hz.
Incidentally that’s not a ‘terrible listening room’, for a largely untreated room it’s actually quite good.
After the waterfall plot with just the main speakers, we’ll need the minimum phase and impulse plots for L, R and L&R. These plots will tell us about reflections. (By working out the path differences, we’ll be able to make an educated guess at which surfaces are causing problems and whether diffusers or absorbers are the best answer.)
From the waterfall, you definitely need more absorption 35Hz to 55Hz
The 80Hz may do with a bit more, but it’s not that critical, leaving it will probably be fine.
The abrupt shift from the left speaker at 75Hz is problematic and suggests significant issue with a reflection (probably from the left wall) and that solving that would be of considerable benefit.
The issues with the Right speaker are far more complex and at higher frequency, indicating that there are multiple structures causing the issues these are much closer to the speaker. These could be associated with the closeness of the speaker to the ‘box’ containing the door. Bringing both speakers further into the room is likely to help this (but no guarantees! ).
Please could you rescale the impulse plot to more clearly show the first 5ms after the impulse. Currently it shows a good RT60 time profile, but the time resolution isn’t sufficient to clearly identify reflections.
Ok will read the REW manual as i suspect the frequency sweep i used was incorrect for impulse response measurement.
GIK have advised their biggest bass traps and a 100mm thick absorber on the back wall. I have ordered a 100 x 1200 x 600mm art panel with scatter plate for the back wall. That was the easiest to get past Mrs B as she got to choose the image!
I think once that arrives i will do another set of baseline measurements and then see what effect adding just 1 panel has. I kinda know by now it won’t be enough!
I was also thinking about that 40hz spike on the lhs, could it be the bookshelf next to the speaker acting as a tuned resonator?
I know what you mean and it may be. I slso tried the RK 120s a very small floor stander. They kinda sounded ‘small’ whereas the 150s are effortless. Its always a compromise and i am ok with slightly oversized speakers most of the time!
Coming back to this thread although i havent, added it all up my system is probably worth around 10k so spending a few hundred on room treatment seems a sensible investment for potentially big gains.
But i didnt want to just start buying stuff and judging by ear when, again for a very small outlay of £130 on a microphone and some free software will allow me to measure, make decisions based on data rather than my cloth ears!
Don’t forget that Exposure amps are built using similar principles to Naim amps. The combination of Exposure 3010 pre and XM9 mono blocks is £3k worth of amplification, so similar in performance terms to a SuperNAIT. Yes the K150s could make use of better amplification, but the Exposure system won’t be troubled by them.
That’s easy to check. Try tapping it and see if it resonates @ 40Hz!
I think it’s more likely to be a fundamental room resonance, 3.75m corresponds to a resonant frequency of 45.6Hz, and the shift down to 40Hz could be caused by the slowing of the sound wave by the sofa.