[Ultralight]

Been asking a lot of questions on this journey I just began a short while ago.  Realizing that the most important part of the audio equation is probably my room so it is not just a matter of getting better equipment, but getting better synergy starting with the room limitation.  Hence my question below.

Question. 

For small rooms around 1000-1300 cubic feet (11x13x8 feet),  is musical deep bass down to 20 hz possible. I'm not sure why but I keep reading about larger bassy speakers 'overloading' a small room.  So is that even a fool's errand to try to get the bass underpinning? I'm not looking for accentuated bass but musical appropriate bass as reflected in the recording. 

And if possible, how does one achieve that? 

If not possible, then I'll just give up on the idea and settle for extension down to 35hz but I would like that final octave.

I find bass to provide the foundation/weight for music.

Apologies if this is a redundant question but I've done a search and did not find a thread on this question.

Thank you.  Audiocircle has been absolutely fantastic in helping my wife and I on this journey to get better music reproduction.
UL

[Hipper]

Most speakers don't go down to 20Hz so presumably you will need subs to achieve this. My speakers go down to the high 20s and in fact, using an equaliser, I start rolling the frequency response down around 35Hz. There are apparently only a very few musical instruments that go down as low as 20Hz (a church organ is the obvious one) so I don't know if it is really necessary to go this low.

The key to good musical bass in a small room is room treatment, and speaker/ear positioning. Using bass traps is essential. What they do is absorb bass energy in the room corners that add or subtract to the bass you hear at your listening position. With good bass trapping you actually hear more bass, but it is the bass of the music, not the room. It really does make a marvellous difference resulting not only in better bass but better all round sound.

The reason why bass is a problem in small rooms is that the wavelengths of these frequencies are of the same order as the room dimensions. For example a note with a wavelength of 11' has a frequency of 102Hz. Usually it is the half wavelength that is the problem so you may well have issues for a frequency with a half wavelength of 11', namely 51Hz, for 13' - 43Hz and 8' - 70Hz (a 1,000Hz frequency has a wavelength of 4"). These problems translate as boomy bass or no bass. You can hear this for yourself by playing some bass through your speakers and walking round the room, including the corners. You will hear different levels of bass in different locations.

http://www.sengpielaudio.com/calculator-wavelength.htm

Some info on the subject is here under 'Education':

http://www.gikacoustics.com/

...and here:

http://realtraps.com/

This gives one idea on speaker positioning:

http://www.barrydiamentaudio.com/monitoring.htm

[Tone Depth]

To hear a clear 20hz tone you need a room with a length of at least 28.25 ft, which is half the wavelength of a 20hz tone.

With a 13 ft room length, you should hear clear tones down to about 45 hz. You should be able to hear lower tones, but they will be distorted by room resonances caused by standing waves. Read about the basics here: http://www.acousticfields.com/wavelengths-in-our-rooms.

"Sound treatment" in rooms attempts to decrease the volume level of the resonances at your listening position so the resonances won't interfere as much with your hearing of the pure tones.

Been asking a lot of questions on this journey I just began a short while ago.  Realizing that the most important part of the audio equation is probably my room so it is not just a matter of getting better equipment, but getting better synergy starting with the room limitation.  Hence my question below.

Question. 

For small rooms around 1000-1300 cubic feet (11x13x8 feet),  is musical deep bass down to 20 hz possible. I'm not sure why but I keep reading about larger bassy speakers 'overloading' a small room.  So is that even a fool's errand to try to get the bass underpinning? I'm not looking for accentuated bass but musical appropriate bass as reflected in the recording. 

And if possible, how does one achieve that? 

If not possible, then I'll just give up on the idea and settle for extension down to 35hz but I would like that final octave.

I find bass to provide the foundation/weight for music.

Apologies if this is a redundant question but I've done a search and did not find a thread on this question.

Thank you.  Audiocircle has been absolutely fantastic in helping my wife and I on this journey to get better music reproduction.
UL

[galyons]

That is tough!  The length of a 20Hz wave is 56.50’.  You need at least one half wavelength distance to propagate the wave by reflecting off of the back wall.  When you do not have at least half a wavelength distance, then the room builds resonances, (room modes), and standing waves.  This affects not only the bass, but the entire spectrum of audible frequencies.  Some frequencies get emphasis, some get sucked out.  Using the half wave as a rule-of-thumb and your longest room dimension, 14’ as the half wave length, theoretically, 43.5Hz is your bass limit before you start having major room size issues.

You can "treat" the room, but doing it correctly is costly and time consuming.  You cannot defeat physics with foam! Match your speakers to your room. Use placement, treat for early reflections and nodes created by reflections of the 6 surfaces.  Don't create unnecessary problems.

Of course, YMMV!

Cheers,
Geary

[*Scotty*]

Check out Duke Lejeun's Audio Kinesis Swarm subwoofer array in the Designer's Circle.
Also see the Industry Sponsored Threads for HAL's MS-3 PC Music Server and dspMusik 6x8 DSP crossover and Hi-Rez DAC.http://www.audiocircle.com/index.php?topic=132170.0
This DSP crossover/Hi-Rez DAC can, by the use of digital delay, fit well defined bass response into smaller rooms.
Either approach or a combination of the two can probably yield the results you want.
Times have changed and you can have your cake and eat it too by applying the proper technology.
Scotty

[poseidonsvoice]

Check out Duke Lejeun's Audio Kinesis Swarm subwoofer array in the Designer's Circle.
Also see the Industry Sponsored Threads for HAL's MS-3 PC Music Server and dspMusik 6x8 DSP crossover and Hi-Rez DAC.http://www.audiocircle.com/index.php?topic=132170.0
This DSP crossover/Hi-Rez DAC can, by the use of digital delay, fit well defined bass response into smaller rooms.
Either approach or a combination of the two can probably yield the results you want.
Times have changed and you can have your cake and eat it too by applying the proper technology.
Scotty

To augment what Scotty has said...to the OP, please read parts 1,2 and 3 (in that order) of this:

http://www.hifizine.com/issues/bass-integration-guide/

Best,
Anand.

[galyons]

One can process the crap out of any music signal to get it to measure the way you like. But, IMO, you are listening to the process and not the music.  Kind'a like 'Auto-Tune' for your room.  Make it sound anyway you want, but, again, IMO,  you are no longer in the world of high fidelity audio reproduction.  But, the only ears you have to please are your own!

Cheers,
Geary

[Pete Schumacher]

You don't need a room of a certain length to hear 20Hz.  Below the standing wave length of the room, the room will pressurize evenly, an effect known as cabin gain or room gain.  That's why it's so easy to hit 20Hz in cars.

Once you get below the half wave length of the room, the room "lifts" the bass response at 12dB/octave until room leakage (doorways, windows, air vents) causes the pressurization to flatten out.  The smaller the room, the earlier the effect kicks in.  The nice thing about the 12dB/octave room lift function is that it compliments the roll off of a sealed woofer.  That's why sealed woofers in cars produce the highest sound quality.  Vented enclosures with extended bass response will produce pronounced humps in the frequency response below the knee of the room lift function.

In your small room, a sealed woofer of proper displacement will easily produce audible 20Hz as long as you seal off the openings.  I'd recommend dual 10" woofers to accomplish the task.

If you have Excel, Jeff Bagby has an excellent simulator that calculates baffle diffraction and boundary effects for speakers.

http://audio.claub.net/software/jbabgy/BDBS.html

It's all based on Allison's work.  Great tool.

[JohnR]

You don't need a room of a certain length to hear 20Hz.

I wonder why people think this. It seems to be repeated again and again when both the evidence and even an intuitive look at it would quickly dismiss the notion. No offence intended to any posters above.

[poseidonsvoice]

I wonder why people think this. It seems to be repeated again and again when both the evidence and even an intuitive look at it would quickly dismiss the notion. No offence intended to any posters above.

Yup. And what Pete S just said. Low bass is definitely achievable. But low bass that is flat without peaks and valleys? That takes some work but is also achievable by learning from Paul Spencer's article I referenced. I would rather have a non lumpy bass response than extension to 20Hz that is lumpy any day.

Best,
Anand.

[brother love]

To augment what Scotty has said...to the OP, please read parts 1,2 and 3 (in that order) of this:

http://www.hifizine.com/issues/bass-integration-guide/

Best,
Anand.

Very thorough, informative reference material.  Thanks for posting this! 

[JLM]

20 Hz is an arbitrary goal that the industry set in the 1960's to be applied to electronics.  Since then it's been latched onto by marketers.  HT and the largest pipe organs can reach below that.  But the only musical instruments that can reach below 30 Hz are contrabassoon, harp (!), organ, standup bass, and tuba.  Rock and roll bass is typically centered around 60 Hz.  The untrained ear can be easily fooled into believing that it's hearing deep bass.  For example the famous cannon fire heard in Tchaikovsky's 1812 Overture (recordings using actual 19th century cannon fire) is actually centered in midrange frequencies.

Again, recommend searching Audio Circle for "swarm" and reading Floyd E. Toole's "Sound Reproduction" to learn more about how to best reproduce bass in residential rooms.  Rooms have acoustic "split personalities".  Higher frequencies behave as rays, like billiard balls bouncing off the walls.  Below the Schroeder frequency (unique to each room, but roughly 140 Hz) sound behaves as waves and the room as a resonator (where the size of the sound waves match the primary room dimensions).  This wave behavior makes for uneven sound pressure levels (volume) throughout the room. 

[Pete Schumacher]

Yup. And what Pete S just said. Low bass is definitely achievable. But low bass that is flat without peaks and valleys? That takes some work but is also achievable by learning from Paul Spencer's article I referenced. I would rather have a non lumpy bass response than extension to 20Hz that is lumpy any day.

Best,
Anand.

Multiple subs at proper locations to create peaks at the listening position is what you're after.  Peaks can be EQ'd to flat.  Dips (nulls) cannot be EQ'd.

I like having the sub in the near field if possible.  I did an installation of a quartet of 15" woofers placed less than 2' behind the seating positions.  The enclosure was a raised platform behind those seats.  With those subs literally playing into your back, there was no discernible lumpiness in response.  Visceral!!!

[harley52]

 WhenI started reading the info at acousticfields.com I thought to myself, have I had this wrong all these years!!! And the outfit with this opinion is giving out advice on room acoustics. The first thing I thought was how is it possible to get deep low end in a car. Then I read the rest of the thread and I see that acousicfields.com is nutty. Where, oh where do people come up with this idea of junk science/audiophile silliness. This isn't the only misinformation out there. Some audiophiles just make up crap that is oh so wrong. The sad part of all this is that some people believe what they read w/o any research and they turn around and wrongly inform others of this quackery  and they never get to the truth. 
.

[bladesmith]

You can produce 20hz in a small room. It will just bounce all over or it can be absorbed/deadened with some acoustic materials. I haven't gotten there yet with my system, but, I believe there is a lot of credibility in adding quality sound proofing/acoustic materials to your listening rooms.

[*Scotty*]

Low bass in cars is actually very easy to achieve. I used an 8in. sub in a sealed box that was flat to 50Hz, then with the 12dB/oct. acoustic gain you get from the tiny space you are loading I hit 20Hz and below with no problem. I did however have better bass extension with the window open to give the pressure somewhere to go.
Scotty

[bladesmith]

Low bass in cars is actually very easy to achieve. I used an 8in. sub in a sealed box that was flat to 50Hz, then with the 12dB/oct. acoustic gain you get from the tiny space you are loading I hit 20Hz and below with no problem. I did however have better bass extension with the window open to give the pressure somewhere to go.
Scotty

I find that opening several windows in my listening room helps, too....

V...

[Tyson]

A swarm approach can work and work very well for dealing with room modes.  The downside is size and cost - 3 to 5 subs, plus main speakers is a lot of real estate, and a lot of cost.  That's why I like Open Baffle for subs and bass in general.  You only need one or 2 and they work by minimizing room modes, which is the opposite of the sealed sub swarm approach, which seeks to excite as many room modes as possible.  Very different approaches, but they both work well and are both FAR better than just putting a sub in a corner and calling it a day....

[Rob Babcock]

I wonder why people think this. It seems to be repeated again and again when both the evidence and even an intuitive look at it would quickly dismiss the notion. No offence intended to any posters above.

True, it's a common misunderstanding.  If it were true then headphones would only reach down to 400hz or so!

[Glenn Kuras]

True, it's a common misunderstanding.  If it were true then headphones would only reach down to 400hz or so!

BOOM!! That is enough proof right there. 

WhenI started reading the info at acousticfields.com I thought to myself, have I had this wrong all these years!!! And the outfit with this opinion is giving out advice on room acoustics. The first thing I thought was how is it possible to get deep low end in a car. Then I read the rest of the thread and I see that acousicfields.com is nutty. Where, oh where do people come up with this idea of junk science/audiophile silliness. This isn't the only misinformation out there.

I read misinformation daily on room acoustics. Sad but true.