Those magical days when the HVAC is off

I have a very small floor fan @20 feet away (on low, circulating that cool air),  and a hepa filter on low @ 10 feet away.  You’d swear you can’t hear them while running.  BUT,, put some music on,, then turn air movers off.  Huge improvement in clarity.  It’s like adding a new component.  In my house thru my ears,, but universal I bet.  I don’t think it’s an electrical issue. It’s the quiet rush of air. 

The last 2 mornings, it been mid 50’s outside when I wake up!  Kansas in August!  Windows open, AC off.  Nice

You could run your system from a simple 'plug in' battery back-up. Companies, like Ecoflow,  will bypass your electrical grid completely.

They have batteries to power everything including your whole house. You just need a small one for your stereo. 

People assume its only quality of power impacting the audio systems when in fact its just as likely or more likely ambient noise levels are being affected. Furnaces/AC add both mechanical and air movement noise in your listening room. To what extent depends on type and placement of these systems. In any case higher ambient noise levels mask or cancel out low level information on recordings to some extent, and some FREQUENCIES more than others. Some have argued I make a mountain out of a molehill with this issue, and sure if you only listen to highly compressed pop/rock at high volume levels no problem. But if you listen to less compressed, quality recordings at moderate and lower volume levels perceived resolution and transparency of your system is being negatively impacted. I'd suggest the biggest reason people state their systems sound better with late night listening sessions is due to lowering of ambient noise levels as the world settles down.

Here's some examples of noise levels in db,https://noiseawareness.org/info-center/common-noise-levels/

My heat pump / air handler is about 25 feet from my audio system in an enclosed room that is well sonically insulated. I also have a variable speed air handler and pump so, is if the house is only slightly warm… it is on very low and barely running.it is not at all obvious it is running.

That said, when running at all it increases the ambient background noise from the high 20db range to the mid-thirties… and negatively effects listening. What is amazing is that it does not just effect really quiet passages… it effects all but really loud ones. I am not hearing any electrical effects, just the increase in the background noise level.

My air conditioning system can be remotely controlled on my iPhone. So, I will temporarily turn it off while listening. Or even pre-cool a bit before a listening session.

I use an oversized iso transformer (10kVa) for my main system, which draws very little current. The AC system also has variable speed compressors, not just variable speed fans, so once set temperature is reached, the compressors wind down and function as dehumidifiers. I’m in Central Texas, where air conditioning runs pretty much constantly. Until the building boom here, the grid was not only more stable, but very quiet. It is still quiet compared to where I lived in the lower Hudson Valley (old infrastructure) but much more "iffy" with the demands now being placed on it. FWIW, the outdoor air compressor units are at the opposite corner of the house from the listening room. 

We just finished installing a large 26kVA back up generator, and I had the contractors wire it in such a way that the electrical subsystem for the main hi-fi is not connected to the ATS for the generator (in other words, the system will not be powered by the generator if the utility power goes out). None of this came cheaply, but was worth it in my estimation for peace of mind. Given that my speaker system is 104db sensitive, I can hear any power or grounding anomalies and it is dead quiet.

The other aspect is ambient noise in the listening area. I measure around 32 db C weighed during the day. I can do more to quiet the room by using soundproofing, not just acoustic blinds, on the dormer windows facing the street, but usually don’t bother. I do not use "power conditioners" or noise trapper type tweaks, as such. The house is also very well constructed, old, longleaf pine and when it was restored, the insulation used (shredded denim in netting) was installed. Room to room dialog is almost impossible because of the construction/insulation methods. (Walls are shiplap, not just drywall).

PS: AC Infinity makes duct fan silencers if you hear air rush through your vents. I first got onto that company when I had a silencer box built for the air compressor that drives my tone arm. I was able to put together a relatively inexpensive fan cooling system with central panel and sensor for inflow and exhaust fans for the silencer box. Now, it appears that they are big on leaf growing equipment. Go figure, as they say in Jersey.

Same here.  I shut down all the ac systems when I listen.  I don't know if it is the sound from air through the vents or noise on the AC lines.  Big difference.  Same as GHD, I cool down (or heat) the house before listening then shut it all down.  

I have VVT dampers in ducts. Air handlers are in the attic (2 story house) listening room is on the 1st floor. avg 38db with AC on. quite in comparison to some. 

The lowest ambient noise levels I can achieve in listening room is low 30's on quiet nights, this living on relatively quiet street, traffic is the worst for ambient noise levels. Daytime 50's and above. I can only imagine what I'd hear with something like low 20's. I'd suggest using resources to improve one's home and listening area to achieve lower ambient noise levels is equal to or better than using those resources to purchase a new higher resolving component.

I fully understand and appreciate the HVAC sound issue you have raised. Here are some tips I offer, after having 11 new home constructions in Southern California, Northern Virginia, and the South Carolina Low Country. (1) During construction, specify your preferred location for the air handler, intake and output vents, and thermostat. (2) During construction, insist on knowing the wall, floor, and ceiling insulation grade. (3) For a second floor, insist on a sealed wood floor with “glue and screw” versus a nail gun. (4) Investigate carpet padding, material and method of installation before choosing the flooring. (5) In an existing room, ensure that the HVAC access points to the attic or side walls have an insulation blanket affixed to the door/crawl space. (6) Select HVAC filters that balance your need for purified air and the noise generated by air flowing through the intake vent. (7) Have your HVAC system professionally checked for air output flow and balance.  (8) Ensure your windows are well insulated to minimize outside noise and your neighbor’s HVAC systems. (9) Have your roof treated with an environmentally safe sticky substance to deter pigeons and ravens from cooing, squawking, and bouncing off windows and metal exhaust vents. (10) If all else fails, put on your best headphones and enjoy the music.   

I see some of Paul McGowen listening rooms use Mini-split AC units. They are extremely quiet. 

I don't have AC.  Love it.

Increase the # of grilles in your room if possible.  If you have 300 cfm coming out of one grille it is quite a lot louder than 2 grilles at 150 cfm.

Oversize Return air.

Keep dampers adjusted at plenum, not at grilles. 

Excellent variety of approaches - I had assumed someone would recommend a robust power filter or regenerator, or power factor correction, etc. though a few have mentioned getting off the grid via battery power- I assumed I was enjoying less stress/usage on my section of the power grid with my neighbors and myself turning off the A/C for a bit - interesting that the majority see the improvement related to the absence of excess air circulation and the noise from the movement of circulating air and the associated noise created by the various motors, fans, pumps, etc. which makes sense. I figured someone had maybe installed a giant/expensive power conditioner/stabilizer/regenerator to fend off the myriad HVAC noise creating nasties, but not so, not yet.

@ostemo8- your original post and the comments it has generated have raised a number of different issues relating to different kinds of "noise." When I was doing the whole house generator, I was looking at the current draw of air conditioners- some of the older type units pulled a huge amount of current on start-up- in the neighborhood of 100 amps! Newer units are not only far more efficient but depending on the type of compressor for the air con, can vary significantly in start up power and running power draw.

You have gotten some good input on noise reduction within the listening room relating to HVAC and overall noise reduction in the listening room. You may not have the luxury of starting from scratch in terms of construction--my room was done within an existing 1880s house that had been completely restored to high preservation standards circa 2004. Some of the things--insulation for example- were done by the previous owner, but the air conditioning units (and furnaces, along with electrical work) were all done by us after we purchased the home in 2017.

One thing I suggest before people get spendy on power accessories for hi-fi is to have an electrical system "audit" done, preferably by a commercial level electrician. I have had the meter pulled by the utility to check the meter block (corrosion can be an issue), and to go over the main service panel, both for integrity and wiring. When I did the electrical "subsystem" for the hi-fi, I specified a sub panel with copper buss bars. That is what feeds the big iso transformer, via 4 gauge wire, which can help with some electrical "noise."  This additional service is then fed from the output of the iso transformer to the listening room in 4 gauge to another service panel adjacent to the listening room, where the dedicated lines (10 gauge) are fed.

It is certainly possible that the HVAC system is contributing to electrical "noise" on your hi-fi but it probably depends on the particulars of the HVAC units, their age and how they are wired, all in relation to how the hi-fi electrical is wired. Most modern houses are 200 amp service, but the reason I like an "audit" is that a lot of problems start with corrosion, bad wiring, deteriorating service panels (in Texas, it is not uncommon for the service equipment to be outside, not in a basement), placing further demands on your electrical system given the elements.

When I had the back up generator installed, I also consulted Rex, one of the guys who helped Fremer sort out the electrical system nasties in his system. Rex can do this remotely, for a modest fee, using photos, drawings and phone calls.

Otherwise, I think you’ve gotten some good input here, including from the contractor @rock-on for all the different factors that go into new construction.

I’m no guru, I’ve done a number of dedicated rooms over the years and learned from each experience. A lot of this is know how, rather than just buying a black box. Because my house is old, and the floors are all longleaf pine (stuff that is now quite costly to find and replace), I also stiffened joists and added a subfloor where my turntable and front end is located. I still needed better isolation for a very high mass turntable (245 lbs), so had to resort to a big Minus K isolation system, which sits under an HRS platform. That does not seem to be an issue for you, so it is irrelevant but it does show the lengths to which you might need to go in some existing situations where you don’t have the luxury of starting from scratch.

Bill Hart

It is listening bliss when it’s chilly enough to have the windows closed, but not cold enough to need to have the furnace running.

Some great ideas given! 

I had planned to wrap my upstairs air handler in soundproofing blankets and I bought Dynamat to line the inside of my air handler access wood door. But at the lower air grille intake/electrostatic 23.5"x23.5" air filter is where the majority of the noise is generated. I turned down my handler's pull power but still. About 30db. I don't know how to mitigate that.

I like the simple idea of pre-chilling the house before any serious music playing. My house is concrete bricks so the helps with temperature regulation. 

This is an interesting thread.  We also are enjoying cooler weather in Chicago and yes it does sound like my system has kicked it up a notch.  My house is is 110 years old and my listening room is in the upstairs which is routinely 10 degrees warmer than the lower levels.   The tubed equipment in the listening room also pumps out heat which makes me further crank the ceiling fanI tend to listen to my HT system in the basement in July and August for that reason but it’s great to be fully enjoying the main system with the window open!

In my house of stereo, I use a whisper quiet in wall AC/heat unit. Since the construction is ultra insulated, all I usually ever use it is on the dry setting. I can't hear it even with music off. Meaning I enjoy comfort and ultimate sound no matter what the outside temp is. And I'm around Austin, Texas, no relief from heat yet, 103. It did cost a lot to build the house of stereo though. Like the saying goes, you get what you pay for.

Not going to argue whether or not a system sounds better without the AC/furnace running , but it would seem that sitting in an uncomfortable room as the temp rises would create a distraction in an of itself from enjoying the music. I live in a suburb of Memphis and it has been hot as hell and humid here the majority of the summer, I’ll take the AC with the music and deal with whatever the marginal listening impact, if any, there is.

@rock-on amazing comments you have.

Also incredibly disturbing to hear is Leaf blowers and revving of such, being used during the summer all over the place even though there’s no leaves. Very important to remove every single piece of grass on a sidewalk so it’s not too cause something unslightly.

Leaf blower use causes environmental issues where birds are less frequent in areas where use of Leaf blower use proliferates. Which is just about everywhere. Also pollen count kicks up with all the blowing in the bushes for those who have those types of problems. And it also damages hearing because it’s really really loud for those being outside.

@ostemo8 I didn't mean to hijack thread from your electrical concerns to the noise issue, AC quality is an important issue, its just that its common to see threads attendant to electrical noise on AC grid and or home AC, I see very few threads on the environmental noise issue. Outside of the audio equipment itself, AC quality, listening room treatment and noise pollution (both home and external generated) are equally important for maximizing system potential.

The most irritating thing about ambient noise levels is often one has very limited control over it. Rock-on has great ideas for minimizing it, but many of us don't have option to implement all of those ideas. You can turn off your HVAC at certain times, but other times you just have to put up with it, the issue is once you've experienced those magical listening sessions when ambient noise levels were at their lowest, subsequent listening sessions with higher ambient noise levels may impact your enjoyment.

Doesn't bother me at all.  Equipment is manufactured to be so silent that the sound quality is not compromised.

Happy Listening.

My system is on all day for my wife's background music. The HVAC runs around the clock in summer (southern Nevada). One benefit of class D that people overlook is the much lower amp draw. I had an electrician look over my 500 watt class D system and he said it was nowhere near unsafe or needing any special wiring. We're on a solar net metering plan trying to go net zero. 

We demand space, price, and energy efficiency from all our residential systems including audio. It is producer degree of difficulty, technology, simplicity. Our Yamaha NS-5000's are an example: 3.5 pound woofer coils with proprietary carbon fiber in all three drivers in a 600 watt studio monitor built and painted in a piano shop.

@bigkidz +1

On another site a member was chest puffing about all the money he spent on his dedicated listen room, dedicated lines, and equipment, but then stated that he needs to disconnect his refrigerator to maximize his listening experience. Obsession for some

As a lighthearted note regarding home music rooms and protecting against external noise, even the best plans go awry. I had carefully reviewed the blueprints being used by the prime and subcontractor team. Since the architectural design, construction, and amenities were largely inflexible and I was unable to be on site, I was compelled to restrict my personal inspection to designated phases. The bottom line is that the construction manager took it upon himself to change location of attic and wall access points, air ducts, and electrical power outlets. He also decided it would be easier to locate the bi-level HVAC unit adjacent to the only long wall and place the air compressor right under the listening room window. He also informed me that the parent construction company did not authorize glue and screw for upstairs composite flooring and only used nail guns. And by the way, the high grade padding and bur-bur carpeting was no longer available, since negotiations with their supplier had broken down. [NOTE: The cautionary statement: "We reserve the right to change specifications and construction materials... " is there for a reason.]

So my wife and I moved into our new "dream" home in Summerville, SC. Shortly thereafter, I noticed a high level of humidity and musty odor in the upstairs music and collectibles room. "Whoops!" The window and room vent exhaust contractors forgot to seal the units and the incessant rain and humidity quickly saturated the wall and ceiling board. And the upstairs floor creaked and squeaked with every step, which the contractor remedied by pulling up the cheap pad and carpeting and yanking out the nails with a crowbar.

However, there is good news. When the house was hit by lightning, the strike was largely diffused by running to ground. Unfortunately, I had failed to unplug my audio equipment from the wall and the amps went into protective mode. But that's another story.        

Three years ago we purchased a 30+ year-old, custom-built home.  Last month we replaced the windows - with 'unbalanced-pane' windows. These unbalance windows have a 2mm pane of glass on the exterior-side and a 3 mm pane of glass on the interior-side.

Our home is MUCH QUIETER now.  Unfortunately, new windows cost as much as a high-end component (or even system).  Still, if you need or want to have new windows installed, they can significantly reduce the ambient-noise floor.  I hope the 'unbalanced pane' tip is helpful to those considering a renovation.

@gdaddy1 

You mentioned the mini splits that PS Audio has in their listening rooms.  Paul hates them and turns them off when giving demonstrations.  We just added a room to our house and put in a highly recommended Mitsubishi heat pump. On its regular settings, it’s pretty quiet, but it’s still loud enough that I would still turn it off during a listening session.  However, it does have a whisper mode and I can’t hear it when standing in the doorway.

To the OP..make sure ( if possible  ) those “ multiple dedicated lines “ are on tge same phase of the panel ANd opposite the big motor loads…

A high end Mitsubishi mini split is 42 db…. 

Don't think it's a power issue at all, but noise floor issue.  In the cooler mornings, I open all the windows, and doors. Trying to air out the house to cool it down for the hotter days. With my from door open, I have to turn up my system, with the door closed I turn it down to get the same sound level to my ears. I live on a dead end street, with almost no ambient noise. 

In my HT room, the HVAC is on the other side of the wall, with a big air return in the ceiling. In there, the HVAC does affect the sound, but as above, it's a noise floor issue, and not a power issue. 

Good call out, with adding damping material to the heater ducts. Think I'll give that a try.

When it's 100+ outside, I ain't turning AC off for even a second, but lately the mornings were cool and nights too in Ohio!

Ah, we all just try to tune out the noise from HVAC systems, but I was taken aback last year when I tried some noise cancelling Sony Bluetooth headphones a friend had brought to work. Wow, such a calming reduction in ambient noise was amazing.

Hearing all this noise all day long working in an office adds to stress and yes, affects our perception of how "good" music sounds. While I never bought any noise cancelling headphones, at least I know they can be a benefit. I just didn’t want to pop $349 for them.

I live in NC. Fortunately, there are about four months out of the year that no HVAC running is needed for heating or cooling at home. Ah, peace and quiet.

Everything that is plugged into an electrical wall outlet,is drawing electrical power....whether it's turn on or not...it's drawing power,check you elect bill...then start unplugging devices.People have,coffeemaker, toasters,blenders,Stereos Receivers ,amps,turn tables,cd players,vcrs,cassette decks,all your audio equipment, TVs,Microwaves,they have clocks in every rooms Unplugging will reduce your electric bill by alot.Also reduce watts used.

@moonwatcher I lived in Durham and only needed heater few times in the winter. Luckily my neighbor on the floor bellow was extremely warm loving so he'd run heater that would heat my floor sometimes to the point that I had to open windows even in January. Other than that, I'm perfectly fine if the temperature inside my home drops to 58.

"Power Conditioning" is a catchall term that can mean just about anything.  Many will disagree with me, but they are the same people I see arguing because they mean one thing by the term and the other person means something else.  I think of power conditioning as an attempt to filter our the noise and leave the 60hz sine wave intact--a fools errand.  

Power regeneration is the process of rectifying the incoming AC to DC, then inverting it back to a perfect AC 60hz sine wave using a very high quality inverter.  However, they aren't always called that.  PA Audio calls them "power plants" for example.  

So a regenerator is what you need and what I use.  that said, not all components benefit from the regenerated power.  I have very damaged power waveform coming into my home, usually running 2 to 4 % THD.  This isn't caused by my own load, or the load of my neighbors, but by the combined load on the neighborhood 12Kv circuit and perhaps even on the higher voltage transmission line.  

The output of my regenertor has  0.1% THD.  That said, some components seem to sound the same on wall power or regenerated power, because they have an excellent power supply that deals with the imperfect power.

My main complaint about air conditioning is the ambient noise.

Frankly, I think the widespread belief that stereo sounds better at night because the power is cleaner is a myth.  I've checked my power many times in the middle of the night and it is just as dirty (3-4% THD) as in the day time.

Jerry

Night time is the right time.

@carlsbad2 correct. Just turning off AC, what about all the other contaminating electrical devices still running in your home, all of it continuing to contaminate AC. And then think about the entire AC grid, we increasingly live in a 24 hour world, I suspect for vast majority of us, grid contamination pretty much same day or night.

The biggest variable day to night is both home generated and externally generated background noise. Also, I can understand why some dismiss this as cause so easily, many live 24/7 in  high ambient noise level environments, we subconsciously block much of it out. And think about epidemic levels of hearing loss today, likely many of us suffer from it and don't even know it. Not only certain frequencies can suffer, but low level info and micro dynamics simply unheard. Think about how many of us not really hearing full potential of our systems, between ambient noise and hearing loss, could be a lot!. people simply don't know what silence sounds like anymore. Go to an anechoic sound chamber, you'll be freaked how loud just your breathing is.

@sns 100% agree that I think the big difference is background noise, both inside and outside the home.  For a second I thought I was accidentally reading my own post.

Late night is great 'round here. '20's background until MOMA flies over...but somebody's getting saved potentially....  my ambient is low otherwise..

Night temps are drifting down into the '60's. so the AC can get shut down...

I’m not sure if this has been mentioned already, but I’ve had this exact experience and my sister pretty much always sounded better after 8 o’clock at night.

I do use conditioner and that helps some.  Pretty good success with running my stereo off a large battery.  It’s worth experimenting with both of these Options.

I would say the most dramatic results that I’ve heard are with a DC blocker.  DC current alter the sound by adding noise and distortion typically caused by HVAC solar panels and so on and I think it’s going to continue to be a bigger problem with being noisy and dirty and electronic devices as those devices proliferate throughout our homes and neighborhoods.

but not all DC blockers are created equal.  There’s a synchro Uni that I’ve settled on for a price that I can live with and it works wonders.  There are also cheap blockers which claim to do the same thing, but do not.

As always trust your ears.

I may Ido a YouTube video on this. It’s a good topic. It’s worth it.

 - American audiophile 

A couple months ago,,,,,plugged vacuum into kitchen wall outlet.  Dead outlet with no warning.  2 plugs on that wall both show dead.  Original 30 year old contractor grade,, so I replace with commercial grade.  Still dead.  One plug is end of circuit and the other feeds that one, and is fed (shows hot), and a second line out that goes ?   Isolating with breakers shows those plugs are part of adjoining bedroom circuit which tests out fine.  From the basement view it appeared kitchen fed bedroom.  After a week of mulling this over, I called a commercial electrician friend to look at it.  Didn’t make sense to him either.  He looked at the breaker box which looked superficially looked fine.  While gently probing neutral bar with a wooden dowel we saw very fine arcing around connections.  He recommended residential electrician…soon.   Hang in there, this story goes somewhere.   All bedroom plugs tested fine, but gotta start somewhere.  I removed the cover off of plug that appeared to be connected to kitchen.  Ok ,, bedroom feeds kitchen.  Neutral wire from kitchen still attached, but scorched, insulation gone, with the metal on the plug scorched.  That plug still functioning and tested good.  Replace that plug and incoming neutral wire.  That was that.  But,, that arcing neutral bar in breaker box.  Yup, very fine static like arcing still there.  I threw the main breaker and began to retighten all the screws on the neutral bar.  Many needed 1/4 to 1/2 turn to snug down.  No more arcing.  Nice.   So finally here’s the payoff.  The next day I resume my daily music ritual.  The improvement in audio was amazing.  Bigger cleaner wider, and especially airy.  Like upgraded equipment.  Weeks later, it’s still there. The wiring is the only thing in the house that changed.  

After reading through the comments here, I have some work to do.  My no HVAC baseline noise level, C weighted, is ~ 40 db!  I can't avoid the white noise of HVAC on, as there is are two ducts and one return in the room, plus the system is in an adjacent room.  Like many of you, I just try to avoid listening when it's running.  But getting another 10 db of quiet would be nice......

My problem is with the darn fridge running, seems noisier than most. I could turn it off, but then the beer would get cold.

My whole apartment is on a single, 20A breaker.  When I added a Ametek Powervar 8.3 my audio was way cleaner, and the background was black (silent).  It did not make my music clinical, which I've heard people complain about with some "audiophile" power conditioners.  My Ametek unit is a medical grade power conditioner, which is meant for protecting the life and longevity of electronic devices, which I feel more comfortable with.