Newbie question: My room BOOMS at 146Hz. I started noticing it today and it's now ruined listening.

[robo]

I'm pretty new to nice audio equipment, but have been assembling a decent-ish desktop setup in my home office. Right now I have an Allo Volt D+ amp and KEF Q150 speakers, and am using the analog output from my MacBook Pro. The speakers are on my desk on foam wedges.

I was fairly happy with the setup for a few days, until the track 'Gone Gone Gone' (Robert Plant and Alison Krauss) came on. It has a low drum tuned to a D which absolutely overwhelmed the song. I thought that sounded strange, so put on my headphones - and the drum was barely noticeable. Then I played some other music on my speakers, and yep, that low D just booms. All I hear now is D D D, and it's really ruined listening for me.

I started playing around with a sine wave generator and determined that the room seems to just resonate at 146Hz, which is unfortunately a common frequency in music. I also found a trough around 172Hz. Between 146Hz and 172Hz, there's a 33 decibel difference according to a decibel meter app on my phone (80dB vs 46dB) when I hold it near my ears in my normal listening position, which seems pretty crazy.

What can I do about this? It's I've tried moving my desk a bit but it hasn't made much difference. There's carpet on the floor, a bed, but not a whole lot of other furniture. My desk is in the corner facing out, so there are walls behind me.

I haven't delved into room acoustics at all before, but would be keen for any advice here.

Thanks!

robo

 

[suttondesign]

My room resonates strongly at 79hz when I use speakers 3’ from the front wall. I can easily EQ that. What I cannot EQ is a null at 63hz. I therefore use a sub to fill that in from another location.

 

[Matias]

Try moving the speakers too, and if you want to invest 100 usd, as the Mandalorian would say, This is the Way:

 

[escape2]

Try moving the speakers too, and if you want to invest 100 usd, as the Mandalorian would say, This is the Way:

+1

Hopefully there is similar software available for a Mac.

I use EQ APO as well as MathAudio Room EQ with Foobar2000 - they help smooth things out quite a bit.

 

[robo]

I see, so the solution is to actually EQ the music to basically lower the amplitude of frequencies around that 146Hz problem area?

 

[escape2]

I see, so the solution is to actually EQ the music to basically lower the amplitude of frequencies around that 146Hz problem area?

Start with placement, but if that doesn't help, then yes, apply EQ. I have a large peak around 150 Hz as well. But if you truly have a 33 dB peak there, then that's pretty crazy - my guess is your phone app is wrong and it's not as large in reality. Still, it should be correctable.

 

[digitalfrost]

That's pretty normal in a lot of rooms I think. See mine.

 

[Bear123]

I see, so the solution is to actually EQ the music to basically lower the amplitude of frequencies around that 146Hz problem area?

In part.....ideally you need to measure in order to see what your response is like. You will need eq in various places below about 300 Hz or so in order to have accurate sound. A small, decent sub will help greatly as well in order to not be completely missing some frequencies.

 

[wwenze]

The best part about room peaks? They, at least the ones that are audible, are easily more than 10dB, which means even if you have an uncalibrated mic, you can still easily spot them in the frequency measurement.

 

[Rock Rabbit]

Maybe not a good position for speakers to face a near wall. Try the sound with desk against the wall or at least speakers facing out. The reason...:
http://arqen.com/acoustics-101/speaker-placement-boundary-interference/
P.S.: use better headphones...that track has heavy drum

 

[MrPeabody]

Maybe not a good position for speakers to face a near wall. Try the sound with desk against the wall or at least speakers facing out. The reason...:
http://arqen.com/acoustics-101/speaker-placement-boundary-interference/
P.S.: use better headphones...that track has heavy drum

That's a good article. It explains why a dominant issue with speaker-room interaction is the interference/cancellation between the direct wavefront and the reflection from the wall immediately behind the speaker. For a typical distance (from the speaker baffle to the wall), there will be a sharp dip somewhere between 100 Hz and 150 Hz.

Robo reports a pronounced peak in this range, which is unusual and difficult to explain from the perspective of room effects. I am inclined to speculate that the observed peak in the response at this frequency may not be due to a room effect. I would be inclined to move the speakers to a very different kind of room, or outdoors if possible, or to the middle of an auditorium, and repeat the measurement, to see whether the effect vanishes or remains. If it remains, it most likely is not a room effect. It is conceivable that the driver's fundamental resonance is this high in frequency. Wherever the driver's fundamental resonance is, the impedance of the driver will be much higher at the resonance than elsewhere, and when driven by a low-cost Class D amplifier with output impedance roughly in the same ballpark as the speaker's impedance, the net effect will be a pronounced rise in response at the driver's fundamental resonance. I would be inclined to consider this possibility, unless I had a very good reason to think it is a room effect per se, and partly because there should be an apparent rise in response at the frequency of the resonance, which begs the question of why it wasn't heard, if it isn't the peak that was heard.

If the observed response peak happens to be due to this other, common effect, then EQ is the obvious solution, more so than when a room effect is to blame. The difficulty, though, is that whether it is a room effect or this other effect, the Q of the EQ notch may need to be sharper than what can easily be realized with any typical graphic equalizer. I don't know about parametric EQ, but at least with parametric EQ you can place the notch right where it belongs instead of an octave (or more) above or below the peak.

 

[earlevel]

I see, so the solution is to actually EQ the music to basically lower the amplitude of frequencies around that 146Hz problem area?

(First, I don't want to start a fight, don't know if this is a sensitive subject on this site, and I'm not against room correction—I helped develop the auto room correction for a studio monitor line some years back....)

As suggested, start with placement, but you've already tried that to a manageable degree it seems. Room treatment is probably the biggest thing, and when you say not much furniture...(geez, I'm lucky to have a room with no parallel walls and ceiling tilted for runoff, floor to ceiling brick corner fireplace, tall book shelves...). One simple thing you might try is maybe a couple of acoustic panels. I realize this may be a living space more than a studio space, but they can look nice and can be made pretty cheaply with corning fiberglass panels, a simple wood frame, and cloth.

Maybe not a lot of helpful info, but as I think you suspect, if you're hearing "D D D", significant time is involved and even eq'ing for the listening position isn't going to fix that. You need to dampen that standing wave.

 

[Scholl]

In my opinion, a resonant peak at around 145Hz looks a lot like the second axial mode of the room height, if the listening position is at half the ceiling height (which is quite possible).

Ceiling height : 2.35m
Speed of sound : 344m/s

Second vertical axial mode = (344/2.35)Hz = 146Hz

If this is the case, then in order to avoid this peak you need :

1) Either having your listening height below or above the middle of room height, like 30% to 40% of room height (which may not be practical)
2) Or treat you ceiling with thick absorption above your head and speakers (which may not be practical either).

If you want to experiment you can use this online room mode calculator. You enter your room dimensions and it calculates which modes it should have. You could try to listen/place you speakers at different heights to see if the 145Hz peak remains.

Here is an example of my former home studio listening room (2,4m celling height, listening position height at 1.2m). Before and after heavy absorption on all the walls and ceiling. No EQ. Among other things, the 140Hz resonant peak completely disappears after the treatment. You will probably not be able to use as much treatment as I, or even at all, but this shows that, in my case, the problem came from the room, not the speakers.

 

[escape2]

In my opinion, a resonant peak at around 145Hz looks a lot like the second axial mode of the room height, if the listening position is at half the ceiling height (which is quite possible).

My listening position is at a height of 3.5 feet in a 9 ft tall room, and I get a peak around 140 Hz as well, although not a 33 dB peak like the OP.

 

[Scholl]

That peak amplitude is maximum when placing speakers/listening position hafway, but it may still be there at other heights. Other modes may also have the same frequency and add-up, it is always a big mess.

Often it is recommanded to avoid integer multiple relations for room dimensions, when placing speakers, listening position etc. 38%, or golden ratios are good mean values for that. But it is just a guideline and not a rule. In your case you are at 39% of your room heights but the peak is obviously still there. Acoustic treatment is still the best way to deal with these problems.

 

[robo]

Thanks for all the responses so far - you all are super helpful and informative!

I haven't had a chance to play around too much, but I swung my desk around the other way, so I no longer have my back to the wall, and immediately that changed things. There's still a peak around that low D but it shifted about 10Hz down and was a bit less intense, so it does seem like this is the room, not the speakers and amp.

I'm not sure the best software to do this with, but I found a Mac app called Boom (ironically) which has a graphic equalizer which lets you adjust in 20Hz increments. Not ideal, but by playing with it I've definitely improved things. I'm basically just using a tone generator (this one https://www.szynalski.com/tone-generator/) and adjusting by ear. I can't get it perfect due to the wide bands the equalizer adjusts in, but it's certainly more listenable now.

If anyone knows of a better equalizer for the Mac that would be great.

 

[escape2]

If anyone knows of a better equalizer for the Mac that would be great.

Take a look here:
https://www.audiosciencereview.com/...ows-linux-macos-ios-ipados-and-android.18450/

 

[robo]

Thanks - I've now got the Soundsource trial installed and the built in AUNBandEQ plugin in use... right now just using a 2 band eq to try to flatten two low frequency spikes. Definitely doesn't sound perfect but it's better.

Thinking about getting a calibrated mic...

 

[dasdoing]

I started playing around with a sine wave generator and determined that the room seems to just resonate at 146Hz

do it again and find out where it builds up.
also use this: https://amcoustics.com/tools/amroc?l=408&w=293&h=243&re=EBU listening room

you can optimize LP, but at the end you will have to absorb where it builds up. good thing is that this frequency is not too hard to absorb (compared with below 50Hz stuff)

 

[robo]

So, bumping this for a bit more advice.

I've been holding off on purchasing a calibrated mic because I'm wondering if I should bite the bullet and get it bundled with a miniDSP 2x4 HD, and then from looking at that, wondering if I should pony up a further $160 to get the version with the Dirac Live license (branded as miniDSP DDRC-24).

I understand amrim's review of the miniDSP 2x4 found it's DAC quality to be wanting but I suspect the defects there are less than what I'd notice, while the EQ improvments to sound should be very obvious. I believe the 2x4 HD's hardware would also let me later add a powered subwoofer to my system via it's crossover functionality, so I'd kind of be killing two birds with one stone.

So... 1. does that sound like a good plan, vs just getting a mic and doing it via my Mac, and 2. Would paying the extra $160 for Dirac Live be worthwhile over using the free REW? Convenience is definitely worth something to me, especially as I'm currently moving my desk around not infrequently so if it saves me significant time each time I re-calibrate that would be worth it.