How quiet is your room?

rockadanny · « **on:** 13 Feb 2021, 07:22 pm »

Curious ... What is the measured noise in your room at your listening seat?
1. System OFF
2. System ON

Measured with SPL app on my phone I took a 30 second average in my room while A/C cycle was off, no UPS trucks whizzing by, and no cargo planes buzzing my roof (which is a periodic occurrence as I live near a military air base):
1. System OFF: 20.2 dB
2. System ON: 22.6 dB

The app I used says that is the volume of a mosquito. Ha!

timind · « **Reply #1 on:** 13 Feb 2021, 09:50 pm »

Man, that's quiet!

Which app are you using? What is the weighting the app uses?

I've measured mine with A-weighting and it only gets down to 30-32 db. If I breath, it moves up 4-5 db.

rockadanny · « **Reply #2 on:** 13 Feb 2021, 10:11 pm »

Sound Meter app on my Samsung Android phone.
Not able to specify any settings so not sure how weighted.
Was going to use my Rat Shack SPL meter but it does not measure that low.
Basement room, well treated with GIK panels.

JLM · « **Reply #3 on:** 14 Feb 2021, 01:22 am »

Good point. Lowering the background noise allows hearing a greater dynamic range and at lower spls (to preserve your hearing). My dedicated listening room is completely insulated including ductwork and door. Unfortunately I only have Radio Shack spl meter.

timind · « **Reply #4 on:** 14 Feb 2021, 02:12 am »

https://www.healthyhearing.com/report/47805-The-best-phone-apps-to-measure-noise-levels

I use the NIOSH app listed in the article. It's loaded on on my iphone 11. My system is also in a quiet, well-treated basement.

Listening in a quiet environment is very helpful to getting the most of your system. I find I can hear much deeper into the recording if all is quiet.

rodge827 · « **Reply #5 on:** 14 Feb 2021, 02:53 am »

timind- thanks for the NIOSH app suggestion. I just loaded on my iPhone 11 and I works a lot better than the other app I was using.

So my room averaged 27.7. Quieter than a library but noisier than a mosquito.

I have always used a sound meter app while listening to keep the SPL in check. I find the longer I listen the more I turn up the volume. Sometimes I just don’t know how loud the sound is being all immersed in the music. I try to keep it around +/- 80db-85db with peaks in the low to mid 90db range.

MTB Vince · « **Reply #6 on:** 14 Feb 2021, 05:27 am »

Hey guys, I hate to burst your collective bubbles but smartphone SPL meter apps are totally inaccurate at the extremes of their measurement ranges. I guarantee you that when compared against measurements taken with an accurate high quality dedicated meter, your respective noise floor measurements are a minimum of 10db worse than your cell phone apps suggest.

toocool4 · « **Reply #7 on:** 14 Feb 2021, 10:39 am »

The last time I took the reading in my room, I borrowed a friends proper SPL tool. If I remember correctly I was getting a reading of around 35db, I wish my room was quieter.

My music listening level is between 63db – 77db.

MTB Vince · « **Reply #8 on:** 14 Feb 2021, 04:27 pm »

That 35dBA reading is actually very good in my experience @toocool4. In the evening doors closed and gear switched on or off, my dedicated room manages 34-35 dBA according to the Reed R8050 SPL meter. Measurements taken with my Cross Spectrum Labs calibrated EMM6 measurement microphone and my Macbook running Room EQ Wizard confirm both the accuracy of the Reed SPL meter and the inaccuracy of much lower measured results taken with my wife's Iphone running a popular sound measurement app.

I should add that back when my room was still connected to our 3000 sq foot loft's 10 ton forced air HVAC system I actually had to shut the HVAC off entirely to achieve a sub-40 dBA reading. This certainly wasn't a practical solution for the rest of the household (or the occupants of my music & cinema room). I recently disconnected, sealed up, and patched over all the forced air HVAC feeds and returns to my room and then installed a dedicated Mitsubishi mini-split for cooling and a dedicated ERV (Energy Recovery Ventilation) system for fresh air circulation. With just the ERV on and set to minimum and solo stereo listening, in-room temperatures remain comfortable without additional HVAC from October through April over extended multi-hour listening sessions. Best of all, the ERV set to minimum has no measurable effect on my room's noise floor.

However during the warmer months or multiple occupant listening sessions, rising temps eventually necessitate switching on the mini-split in it's 19dBA "whisper mode". Switching on the Mitsubishi raises the room's noise floor by a trivial 1.5 dBA. With a house-call and expert knowledge of a silver haired engineer from Mitsubishi's nearby Canadian HQ, we sized the 9000 BTU mini-split so that even with seating fully occupied, the projector on, and all the 7.4.4 multi-channel gear powered during the warmer half the year, the Mitsubishi mini-split still gets the job done in it's quietest whisper setting. Contrast that with the 48-50 dBA noise floor numbers I was achieving back when my home's forced air HVAC was still connected to the room and switched on!

Mike-48 · « **Reply #9 on:** 14 Feb 2021, 07:12 pm »

Using the Dayton OmniMic2, last time I measured I got about 29 dB with "A" weighting. Subjectively, the room is very quiet, most of the background noise being below 40 Hz.

I should mention, the room was specially built to be quiet, as it's in the basement with an HVAC system and power-vent water heater on the other side of the basement.

Big Red Machine · « **Reply #10 on:** 16 Feb 2021, 05:24 pm »

I wasn't going to drag out my room measurement gear for this activity. I did use an iphone and an iPad with 2 different aps because I was curious. All off and trying to breathe shallowly, the best I could hit was 37 db. I don't have any real heating duct whoosh but maybe it is more than I can notice right now.

I'll try it again with the gear on, but I don't expect much delta.

Danny, that is one low number.

mcgsxr · « **Reply #11 on:** 16 Feb 2021, 05:48 pm »

iPhone app shows high 30’s for me.

Room was built with an eye on sound transmission prevention but nowhere near soundproof. I have pot lights and other no no’s from that perspective.

It does what it is supposed to do though, and I can listen down there whenever I want at volumes I enjoy.

Still has HVAC serving it so it won’t ever be super quiet but I’m happy.

Longandstraight · « **Reply #12 on:** 17 Feb 2021, 05:20 pm »

I am at 31 in my purpose built room with all equipment on . Above grade 2x6 construction, double 5/8, Green Glue, yada yada. Would love to be in a below grade space.

rockadanny · « **Reply #13 on:** 17 Feb 2021, 05:45 pm »

@Big Red Machine -

Quote

Danny, that is one low number.

Yeah. I was shocked. I've done it a few times to be sure.
Three walls are concrete/insulation/drywall and the room is below grade. And there is a definite, notable silence when you enter.
And I did it at night - when the leaf blowers all go to bed.
Maybe my phone sucks?

Or I am one very lucky audio dude.

If I am able to borrow some real equipment I'd love to check. But I'm not going to lay out $hundreds for a real mic and measurement tools.

nathanm · « **Reply #14 on:** 17 Feb 2021, 05:47 pm »

My room is below grade, which I modeled after my high school algebra performance. I haven't measured, but it's very quiet. I'm a firm believer in absorption. I think this is the best thing you can do for your room. Maybe because it's all I know and I can't afford diffusion, but I still like it a whole lot. Yes, I know that absorbing bass requires big mass and big dollars, but covering the walls with foam and notching out 40Hz with my fancy Roon DSP hasn't steered me wrong.

Knocking down that RT60 in the mids and highs is a huge bonus. You don't have to have any music playing, just walking into the absorptive room from a reverberant one will put you in a better mood. It's like, "Yes, my body is ready. I am ready to listen to smooth jazz." My front and side walls are completely covered in 2" foam and the wall behind me has got some. I'd like to do the ceiling too. Lowering the noise floor makes everything better. Although noise does mask things so you might hear hums and buzzes you otherwise ignored.

MTB Vince · « **Reply #15 on:** 17 Feb 2021, 06:04 pm »

Quote from: rockadanny on 17 Feb 2021, 05:45 pm

...Maybe my phone sucks? Or I am one very lucky audio dude.
If I am able to borrow some real equipment I'd love to check. But I'm not going to lay out $hundreds for a real mic and measurement tools.

As I stated earlier on in this thread, the built-in microphone in all smartphones are hugely inaccurate when it comes to attempting to measure the noise floor of a quiet room. They will typically measure 8-10dBA low in this range when compared against a high quality SPL meter or a calibrated measurement microphone, mic preamp, and a laptop audio measurement suite like Room EQ Wizard.

That being said, even if @rockadanny is actually achieving an accurately measured noise floor in the vicinity of 30dBA, that is a seriously excellent result.

Bill O'Connell · « **Reply #16 on:** 17 Feb 2021, 06:18 pm »

On phone from app NIOSH SLM I registered a 27.2 dB (A )

I guess those 24 GIK assorted panels I picked up locally for $1K has paid off.

rockadanny · « **Reply #17 on:** 17 Feb 2021, 06:50 pm »

@MTB Vince -

Quote

even if @rockadanny is actually achieving an accurately measured noise floor in the vicinity of 30dBA, that is a seriously excellent result.

Sweet!

MTB Vince · « **Reply #18 on:** 17 Feb 2021, 07:08 pm »

Quote from: Bill O'Connell on 17 Feb 2021, 06:18 pm

On phone from app NIOSH SLM I registered a 27.2 dB (A )

I guess those 24 GIK assorted panels I picked up locally for $1K has paid off.

Several of the thread participants here have attributed the action of their room acoustic treatments to their measured noise floor result. This is factually incorrect. Your acoustic treatments have no impact on your room's noise floor measurement whatsoever. Room acoustic treatments primarily effect the sounds generated within the room. A low noise floor is a result of the isolation of your room from external noise pollution and as such is a function of a bunch of factors completely unrelated to your interior acoustic treatment efforts:

First how quiet your surrounding neighborhood is. If you live next to a busy highway or heavy trucking route, airport, or railway yard it will require heroic (and ridiculously expensive) construction methods to isolate your room from the low frequency noise pollution you are experiencing.
Next the construction of your AV room's walls, ceiling, floors, doors, and any windows has a tremendous bearing. Room-within-a-room construction, doubled and Green Glued drywall hung from resilient channel, airtight seals around massive solid core doors, triple pane windows if you must have windows, etc.
The specifics of how you have handled HVAC, air ventilation, and through-wall electrical as all of these holes through your walls will otherwise act as conduits for noise pollution into and out of your room.

Does this explanation all now make sense to everybody whom may have been confused about this?

Mike-48 · « **Reply #19 on:** 17 Feb 2021, 09:34 pm »

Quote from: MTB Vince on 17 Feb 2021, 07:08 pm

Several of the thread participants here have attributed the action of their room acoustic treatments to their measured noise floor result. This is factually incorrect. Your acoustic treatments have no impact on your room's noise floor measurement whatsoever. Room acoustic treatments primarily effect the sounds generated within the room. A low noise floor is a result of the isolation of your room from external noise pollution and as such is a function of a bunch of factors completely unrelated to your interior acoustic treatment efforts.

Well said and accurate. Getting the noise floor down is ridiculously difficult, especially given factors like road noise or even the noise of a refrigerator on the floor above. Structure-borne low-frequency sound is almost impossible to avoid within most people's constraints of space and cost. Fortunately, low levels of low frequencies (<40 Hz) don't obscure musical detail significantly, IME.