Don't Set Your Subwoofer On The Floor! Part 2 - www.AcousticFields.com 

Managing low frequency energy distribution within a room is a large challenge. We have tried all of the multiple speaker approaches but find them lacking in definition and separation. The money spent on multiple LF drivers can be better utilized with treatment for all frequency ranges,

@@AcousticFields - completely agree with your comment.

Thank you for your support and following.

There is a definite improvement on response.

But if they’re close to the ceiling isn’t that the same as being close to the floor?

@@isaacleedrums It is EXACTLY the same, of course the ceiling might be different structure. But it is the same. Best place for subs is definitely on the FLOOR right next to mains. If it flush mounted mains, just below them.

​@DrSamE you don't like change that's why they call you dr. same.

@@DrSamE most high end restaurants also have them on the ceiling. the sound is always top notch.

Glad it was helpful!

Shout it out. People need to change their belief systems.

Nice work!

I do not like to use the word common sense but I think it is appropriate here. Why would you place a low frequency energy producing device next to a room boundary surface ?. Why would you fire energy into a physical structure that is a few inches away from the source? Does the interplay with the room surface produce more distortions that are audible?

@@AcousticFields I agree with your assessments. Love your videos. Very informative. Keep up the great work!

Elevate,attenuate, isolate. These are the goals and design parameters of our sub woofer platforms.

It is always better to keep any energy producing source away from any room boundary.

I had a 69 gold w/black top. My favorite of all was a 327 Chevy II, blue with black interior. Yes, found memories indeed.

Never place a low frequency producing device next to a room boundary surface. You are creating more room distortion when the goal is less. Fill out the info. in this link and include pics of the room with the form. www.acousticfields.com/free-room-analysis/

Look at Emotiva for economical power.

This.

I seriously doubt it will happen, because it will show that lifting the sub off the floor makes very little difference. I've tried it and measured it and listened to it. What does make a difference if you are selling a product that lifts the sub and you can convince people they need it.

What does make a difference is real world testing in multiple facilities not just your living room.

You will get more variation in performance with different placement in the room. Corner no corner , placement. These make a difference height. Not so much

I put only one subwoofer on some unused pair of Dynaudio speaker stands and my results personally was I actually got a substantial improvement in sound quality versus using two of the same subwoofers on the ground. This was with the SVS-SB3000’s. I’ve moved on to Rythmik F18SE’s and I am pretty sure I need to raise the 120lb subwoofer at least 18 inches off the ground…. Not sure what I’m going to use since my subwoofer has the dimensions of a garage ready freezer.

The room only sees energy. It does not care about the method of delievery.

Here is our sub platform: www.acousticfields.com/product/subwoofer-platform-absorber/

Your room response will improve.

Subs should be elevated, they should be placed upon technology that absorbs their excessive energy output close to source and as you point out they should be isolated from vibration transmission.

Glad you liked it!

Our sub platforms perform three functions. They elevate for smoother response, they attenuate or absorb energy and they minimize vibration transfer from the sub to the floor.

Thank you, much appreciated.

It is more important to locate low frequency producing devices in the proper room position rather than using a particular mounting methodology.

Foam will not be able to support the weight of the subwoofer. It will also not provide any vibration isolation or absorption.

@@AcousticFields i didnt express me well, sorry! i meaned i will build a wood platform with fiberglass inside to the sub and would like to know about position the mid/high monitors on top of the sub or in a stand beside? Thank you very much!

Start with 12" and work your way to 18"

Outside venues benefit from raising the sub on the stage. We have placed our carbon technology in the sub risers.

I do not understand your question.

You have described the problem. What treatment do you prescribe?

@@AcousticFields Every room can be like a big jar, the audio energy is like placing various sized solids in the jar. Big rocks are like Bass, medium stones are like mid range sounds while the treble, high frequency sound is like sand in the jar. There is a maximum amount of solids the jar will hold and the same goes for sound energy in a room. Measuring the limit of sound capacity of a room is the first step in every analysis. When the sound energy exceeds the ability for the room to contain it, you either have to reduce the amount of sound (volume) or find a way to transform it. The sound energy remains (reverberation) until it is changed to heat energy since energy cannot be created or destroyed only changed in its form. This transformation can be the room structure and contents or by adding materials within the room to do the transformation.

The direct the sub woofer fires, whether from the cabinet side or bottom, the room only sees the energy coming from. The energy it produces, in all directions, are waves of energy that oscillate through our rooms. Sub energy is emitted in a 360 degree pattern.

What is your acoustic goal? Are you trying to reduce noise transmission? Are you looking to build low-frequency absorption into the walls? What is your sonic strategy? Using tactics without a strategy is a waste of time and money.

@@AcousticFields The entire house is noisy, when someone uses the water in the bathroom, hair dryer. House is 1590 sqr ft upstairs and downstairs (each floor) nice 12 inch studs on the floor, walls are all 6 inch thick but the bathrooms measure at 8 inches. But yes, I would like to reduce general house noise, completely separate from my listening room. When mentioned it to my contractor he said that NO I shouldn't do anything like that in the bathroom. I'm looking at this gap of air??? At a loss. I live 3 streets away from HWY 67 Kids outside often. And during the day I never, or very rarely get under a 37 or 38 db of noise using one of the android apps. I haven't left it sitting there for 24 hours but a average over the 12 hr day, with me talking was at 49db in my living room. I should just move.

Yes, it is the dynamics of pressure.

The isolation that feet provide is only one element of the equation. We have found with our recent subs that the cabinet moves as much as the driver does. We have taken measures to reduce the vibrational signature of the cabinet.

This has been going on for years. Speaker manufacturers are constantly trying to minimize room impact on their products. It will never happen. Once the energy leaves the speaker, the room owns it and will do with it what rooms do, they distort.

@@AcousticFields I agree that first and foremost you have to fix the room and treat the room down to the flattest response you can obtain. But I'd encourage you to check out the system in person if you get a chance, I was shocked by how well it mitigates problems that a conventional sub would typically introduce into the room, it felt like soffit mounted like performance but in free standing speakers without needing to mount, settle on and hope the studio designer picked the correct position for the soffits to obtain maximum performance.

@@JD-qf8ov the problem with genelec w371a is that is used as a speaker stand without height adjustment. So it is tricky to place tweeters on a listeners ear level.

@@adelkharisov I can see how this could be a problem for someone with a very small room that is working extremely close to the system. Otherwise you'd just sit the speakers back far enough while also having your chair at the right height. The three ways you pair the w371 with can also be placed horizontally with no impact to performance or tilted, etc

You're very welcome

Glad you like it!

We do not subscribe to audio gimmicks. We are all about resolution.

Sub woofers radiate energy in all directions. Elevate it off the floor 12" as a start point. Listen to the improvement across all your music sources. Raise it 18". Listen again.

@@AcousticFields thanks for quick response

We will be doing a series of videos on this effort.

@@AcousticFields I used 10” ~10mm xmax woofer in sealed enclosure (could be ported but that was not the case) with crazy lowend correction to be able to see phase and FR below 20hz. Helped to avoid spots in the room like -30dB at 25Hz. looking forward to see comming videos!!! 👍

It depends on the design of the floor. Was it designed as a low-frequency barrier?

Raising the sub is not to reduce noise transmission. Its goal is to smooth frequency response. A floating floor is one method to reduce noise transmission. There are many other options.

You want to elevate, isolate, and attenuate. www.acousticfields.com/product/subwoofer-platform-absorber/

Think about why a sub fires into the floor. It is the same principle as corner sub placement. The goal is more amplitude or strength using the room as a part of the overall sound . This is also the quantity versus quality paradigm. If you elevate, you can improve room response. You can also attenuate or absorb energy close to source and also minimize the floor to subwoofer vibrations.

Don’t fret, down firing subs are great. Everything is a trade off. One great benefit is you hear less of the drivers non linear distortion

If you pressure balance the room, the sub will sound good almost anywhere. The room does not care what you want to do or where you want to place this sub or that speaker. it. It will react to that energy you put into it. It will like some frequencies that correspond to its dimensions, most frequencies below 100 hz. it wll not like.producing pressure and reflection issues. It only sees energy. The room dimenions and how they relate to each other mathematically, will tell you where to position the low frequency generating source.

Always liked that car. I remember trying to get it started in -20 weather. When it did start, the warm up took awhile but you could tell when it was warm by the tone of the engine.

This has been our experience.

The subwoofer is a low frequency producing source. The room does not want it. It will do everything within its physical power to fight with each wavelength that the sub produces. This fight goes on full time at all pressure levels. Finding the proper position is a good first start. Place the sub in the center of the room as a start position. Move 1' forward and then 1' back. Repeat with sidewalls. Elevate at least 18" off the ground for this testing. Spend at least 2 songs listening at each position change. Play a full range song with lots of low end then play a "regular" song with strong vocals

@@AcousticFields In a home theater Subwoofer setup...If sound quality and imaging is the #1 priority...There is only one way and one set of inputs to use...High level inputs directly from your front 2 main channels amplifier terminals. Shared with your two main speakers. I use banana's that allow for second banana to be plugged into them. Whatever "stank" your main two channels amp is sending to your main speakers is the exact same "stank" you want going to your subwoofers (yes, you will need 2) as stereo subwoofers Image as much as any two main speakers...the magic happens when, a quality pair of sub's work together with high resolution speakers to paint the soundscape. Keeping the drivers smaller makes for quicker bass and quicker recovery of the driver. Pair of 12's for impact...absolutely. Sound quality, pair of 8's will do nicely. No, not the 100.00 specials on Amazon unless budget dictates. Stick to the bigger names. Rel performance can be had for less money in say the Martin Logan Dynamo 400. As an example. Most (let's say enough) of the bass signal is contained in the front 2 channels to satisfy the bass needs of any home theater. Switch to 2 channel for critical listening and marvel at the imaging and sound quality. Stay away from RCA inputs. Don't sacrifice any sound quality just for convenience, you don't have to. Having said all that...2 sub's running in stereo are the foundation of the soundscape. Subwoofer's at different height levels would abstract the foundation of every soundscape that is rendered. Unbalancing the stereo image...No staggering subwoofer height's and always (without exception) run stereo sub's. I'm all for getting them off the floor but at the same height for any listening evaluation. Ear level might be interesting.

@@lexicon612 You are forgetting about the room impact. Low-frequency energy is a pressure based event. You are using middle and high frequency ray image logic on a low frequency pressure wave. This is a false comparison. A low frequency producing device is room dependent and must use the physics within the room to produce the proper pressure balance that contributes to the managemnt of omni-directional energy. Have you tried elevating your subs?

@@AcousticFields I'm not going to argue with you till you have set it up and listened to it. 2 sub's in stereo cannot image properly at different height levels. That simple. The image will have weight and the distance between instruments will be palpable. Depth will also be better defined. After you have listened to it how I describe, then respond. My subs are 6 " off the ground down firing.

@@lexicon612 No argument from me. We actually test various methods and are open to new ways. This line of thinking produced the most powerful low frequency absorption technology ever created in any commercially viable product and the smoothest rates and levels of absorption for music and voice ever created using an open celled foam. If you are not open to the physics of sound and how it works in small rooms, you will never understand. You should come to our research facility and I will demonstrate to you the falseness of your assumptions. I will pay for your flight and hotel costs. When would you like to visit?

Sounds great!

Thank you for your support and following.

Yes he does, and I just want to NOT make things worse.

Did you notice an improvement in lower frequency pressure sound quality? Always seperate low frequency sources from each other. The distance apart will depend on room volume along with usage.

@@AcousticFields I will have to check this upcoming weekend. I was too distracted getting used to the new Presonus StudioLive 32SC console.

@@AcousticFields and THANKS!

Place low frequency absorption under the sub woofer. The best place to absorb energy is close to the energy source.

Its not the surface area of the floor that is the issue. It is the structure of it.

Reducing the transfer of vibrations from one source to another will improve overall resolution. Now, carry this thinking further and add mass to your subwoofer cabinet.

@@AcousticFieldsWhat about Acoustic Science sub traps.Do you have any thoughts on those?

@@user-uh1rv2dn5c A low frequency absorption device that one can easily pick up and carry into the room is not a "bass trap". It may go low enough but it will never get enough. Sadly, the story of the industry

LOL yes. I had a Chevelle 396. I remember when gas was 19 cents a gallon. We use to pool all of our cash to get 2.00 so we could get 10 gallons to go 100 miles for an evening of driving around.

You must calculate the proper position for the subwoofer first and foremost. Elevation will improve response if you find the proper location. One attempt when positioning a low frequency source is never enough. It is a process like everything else in acoustics due to the many varaibles involved.

Its not the surface area composition. It is the distance from the driver to the floor the creates the distortion.

Stay tuned.

@@AcousticFields I will.

LOL. I built a cobra 427 kit car. The thing weighed 2200 lbs. with 500 HP. When you jumped on it, the tach and the speedo would move together at the same rate. Miss those days.

Subwoofer manaufacturers recommend placing the sub on the floor for two reasons. The first is liability and the second is quantity versus quality in sound presentaion value.

Glad you liked it

It will depend on ceiling height and room volume.

We have found that multiple subs are not cost effective for the improvements granted. If the cost of multiple subs, which only deals with lower frequencies is spent on treatment, you can impact all frequencies, not just a small group. Stay away from room boundary surfaces. The goal is less room distortion not more. Placing a sub in a corner produces room gain not sub woofer sound quality. It is best to hear the speaker first instead of the room distortion. Quantity is not quality.

Acoustic fields, you don't understand that when you move from the wall the reflection is what causes problems with the direct sound so by limiting the distance of one boundary you get less interference and more of the direct sound. Having the sub in the wall is actually ideal as the reflection is then zero for that boundary. Multiple subs are not a requirement for a single listening chair but as soon as you have multiple seats it is the only way to achieve a uniform response at more locations by breaking up nodes to get even pressure areas in the room. I suggest that you consult the many resources available on the subject. Audioholics has good videos on the subject that site the research sources and explain in detail how bass interaction works in a room.

Once again, quantity is not sound quality. Multiple subs are an expensive way to realize only a 3-5 dB improvement. Most rooms need +1 0 - + 3 dB improvements. This method is an expensive bandaid. Spend you doolars treating the room response. It is the most effective way to produce measurable results over a broader frequency range.

It depends on the dimensions of your room. Ceiling height is a large factor. Start at 300 mm.

@@AcousticFields my ceiling height is about 4 meters.

You are not positioning the sub in the correct place within the room. Move your sub around and try different places elevated.

Is this option available on iphone 12. All of our u tube videos are shot on the 12

@@AcousticFields I’m not sure, but I think the real issue is light source. It *appears* you are using a “natural light” source which is seems to be variable. FWIW, the quality of the light source is really nice - the colour and contrast are great. A fixed exposure would not fix variable light source issues. I can live with it the way it is.

Probably worthwhile to get the iPhone 13 pro max! Cheers and thanks for all the good information regarding audio fidelity and room acoustics that is easier to understand with your usually spot on analogies that help me grasp and understand the concept instead of just hearing it and not actually knowing the how and why. Cheers

I guess it depends on preference. I didn't notice any issues with the video. Nothing distracted me from the information i was seeking

Treat your room and keep your existing gear. You will be amazed on how good it will sound in a treated room.

Did you ever upgrade?

Don't forget elevation in your analysis.

@@AcousticFields that will be the Floor deflection mentioned above. I am currently elevated 2 feet on a wooden floating shelf for a cheap small sub

Acoustic Control measurement mic

It is always best with low frequency absorption to place it as close to the source as you can.

@@AcousticFields why not just build a large box around 5 sides of the sub box filled with insulation?

OMG!! I had thought about subwoofer being suspended in the air with cable to alleviate floor vibration and I'm surprised someone has done this too.

No, subs radiate energy in 360 degree arrays.

@@AcousticFields So is it possible to turn the downward firing sub upside down so firing toward the ceiling. Would that help?

Elevation, isolation, absorption all provided by the chair if it has cushions.

Elevating any low frequency device away from a surface boundary will improve response.

Yes, radiating low frequency energy into room from forward firing drivers minimizes the driver to floor issues.

With subs you must elevate, isolate, and attenuate.

I would not like this at all. It goes against everything we know about sound quality.

This is an easy fix, remove the room out of the equation just use headphones.

@@lorindamikaela I just play out in my yard XD

@@lorindamikaela lol omg

Climb to the highest building in your town and shout this for all to hear.

@@AcousticFields Is this real or sarcasm? I'm thinking of trying to place my sub on a shelf slightly above and to the right of my speakers. Do you think this would work? Otherwise it has to be under my work desk which is not ideal either.

@@sampsalol Keep all low frequency producing devices away from shelves and walls. With low frequency energy, the room does not care what you want.

Thanks for sharing!!

www.acousticfields.com/product/subwoofer-platform-absorber/

You can elevate, isolate, and attenuate with our carbon sub platforms. Here is the link: www.acousticfields.com/product/subwoofer-platform-absorber/

@@AcousticFields Thanks for the link. So essentially it is an absorbent-stuffed box (Roxul 80 or similar). For energy management, there is a volume control on the back of a sub. Absorption up to 200 Hz is quite high, and the vast majority of subs have a crossover frequency adjustment. 30 Hz is not terribly low, as some subs go well below 20 Hz. Re elevation, I can see that removing it from a surface (1 dimensional corner) may be advantageous. But why not an open frame? Maybe slats, as a form of a diffusor? An absorbent-stuffed box can simulate height, but it also will have non-linear frequency response. I am tempted to make an open frame and see what that does. Fun little woodworking project. Looking forward to part 3 with some comprehensive measurements. Will be pretty complex as it involves 3D soundlevels, frequency response, plus room characteristics and then with sub on floor, on your stand, suspended, open box. Will be difficult to generalize. 3D statistics to show significant difference will also be complex. I've done linear series with nested MANCOVAs, but never looked into 3D data stats. Bottom line: conceptually interesting, questionable implementation.

How does it sound? Is there more definition and clarity? Can you hear more of each note?

@@AcousticFields well u get tighter 20-40hz it seems to me

Elevate, isolate, and attenuate with subwoofers.

@@AcousticFields I can't afford your platforms. But I may try Auralex Isodude platform. Thanks!

MLV - mass loaded vinyl

@@AcousticFields interesting, never heard of that product before, I'll have to look it up.

Start your tuning process at 12". Move to 18". Then try 24".

@@AcousticFieldsHow about ear level?

Isolation from vibration transfer is a good start. Now, elevate and attenuate.

Send us your room response curve.

Report back to us your findings.

Study wave versus ray energy

I like the term "air cannon". That is exactly what it is. Why would you shoot an air cannon into the floor or worse yet, put it in the corner of a room.

@@AcousticFields 😂 I was told by a guy. Lol All joking aside; the room is the dictator of the sound. Might work for some one that has the room for it? IDK. Good topic.

It does not provide real gain with real acoustic quality to it. All you have to do to listen to this is to elevate your sub to ear level and listen to the sub away from room boundary surfaces. Compare the attack and decay, definition, and separation of the lower frequencies with this approach to placing it next to a room boundary surface. They are as different as night and day. It is all room distortion.

@@AcousticFields I have done stepped sine distortion measurements. Even at 105 dB at the listening position, the sub distortion is less than 1% THD and the response flat. Provided the sub flooring and walls are rigid enough, you get substantial gain. I put the sub in question into a corner where the floor is concrete and it can attain up to around 115 dB despite being relatively low cost and only a 10 in driver. If the flooring and walls allow it’s worth experimenting with. But as you imply if they move a lot then he sub has to be out of the boundary condition.

@@AcousticFields FWIW I have also done waterfall and spectrogram measurements and the room modes take far longer to die out than anything from the sub.

@@AcousticFields And I have heard what you are referring to, and it sounds terrible. But it’s worth trying the boundary condition if the room permits. In some cases it does, but others not. I would not want to confine myself to doing it one way or another.

Try it and report back to us.

Wow, thanks

I concur with the above. I am 33 years old.

Quantity is not quality.

Firing a sub woofer into the floor no matter what the material composition produces quantity (distortion) not quality.

Thanks for watching!

Give it a try and report back to us what you hear. Try and raise off the floor at least 12".

LOL Yes. That would work.

Make sure it is a free standing plant stand away from the wall.

The floor material type could be an issue but in the overall presentation value, it is a small variable of concern.

I am not familiar with these.

Yes, why would someone place a low-frequency producing device next to a room boundary surface. Manufacturers do this to increase room distortion and gain. They believe that quantity is quality. I have been told many times by manufacturers that raising the sub off the floor creates liability issues which I can understand. What I can not and will not accept that you place a large surface area, low-frequency driver, 3" from a floor or wall.

There is no one size fits all rooms. What will work inside a certain room volume, will not work in another.

Todays subs have come a long way. The drivers are stronger and can move faster. The electronics to manage all of this mechanical energy have improved and cabinet design also. Now, if I could get people to pay this level of attention to their room, I will indeed have accomplished something.

@@AcousticFields I know. If only. Easier said than done.

It could sound better. If you are happy with the level you have reached, then mission accomplished.