[DavidS]

I have a second system in my home office which is a relatively small square room - 13 x 13.  I have loaded up the room with my best gear but as much as I love my Ellis 1801s they are just too much for this small room.  So they are going back to my large living room (18x30) where they will be much happier.  So thinking about my small room the questions I have are:

1.  what qualities should I look for from a speaker for a small room like mine
2.  what is working for you in a small room
2.  speaker recommendations that will sound great but won't overwhelm a small room

Rest of gear in the room is modded PS Audio amp, Audio Note preamp, modwright Sony cd player, and squeezebox.

[MaxCast]

Buy some bass traps and panels for the wall and ceiling.  Put the 1801's back in and try again.

[95bcwh]

My Salk HT3 used to live happily in this small room


But heck, I have about 27 acoustic panels (4 inch made of 8lb/ft3 mineral wool each) 

[bpape]

Ellis' should be fine in that room with:

Proper seating and speaker positioning

Proper room treatmet

Bryan

[TONEPUB]

I second the motion to do as much room treatment as makes sense for you.
Small is tough and square is tougher, but with some experimentation you
should be able to pull it off!

[Duke]

Let me try to explain one problem of small rooms, and then propose a way to address this problem.

First a bit of background:  The ear doesn't distinctly hear every little peak and dip that you see in a frequency response curve.   Rather, the ear averages out the loudness over intervals roughly one-third of an octave wide, called "critical bands".   If over a one-third octave interval the peaks and dips more or less average out, that's good.  If on the other hand the peaks and dips are too large and too far apart for the ear's third-octave smoothing to average them out, then those peaks and dips are likely to be audible.

In most rooms, the effects of room reflections in the midrange and treble results in many narrow-band peaks and dips that usually average out over third-octave intervals.  But in the bass region, the room-reflection-induced peaks and dips are large enough and far enough apart that they stand out audibly.

Let me explain.  Imagine you're listening to a single subwoofer placed along the wall in front of you.  There will be one path length from the subwoofer to your listening position.  There will be another path length from the subwoofer to the wall behind you, and back to your listening position.  At the frequency where the difference between these two path lengths is equal to one-half wavelength, the reflection will arrive 180 degrees out of phase with the direct sound and cancellation (a frequency response dip) will occur.  At the frequency where the difference between these two path lenghts is equal to one wavelength, the reflection will arrive in-phase with the direct sound and reinforcement (a response peak) will occur.  There will be other peaks and dips associated with other reflection patterns, and/or with the room's standing wave modes.  The smaller the room, the higher the frequency at which these too-widely-spaced peaks and dips begin to intrude. 

Now we can move this pattern of in-room low frequency peaks and dips around by moving either the subwoofer or the listening position, or both.  But we cannot eliminate them - we can only hope to find positions that are a better trade-off.

But what if instead of just one low frequency source, we have several?  And, what if we sort of scatter them around the room so that no two of them generate identical peak-and-dip patterns?  Several researchers have studied the idea of using multiple low frequency sources, and they have found that this significantly smooths the in-room bass response not only in the "sweet spot" but also throughout the room.  At least one researcher recommends four subwoofers spread around the room.   And the smaller the room, the more of an audible difference multiple subwoofers is likely to make. 

Now it sounds crazy to contemplate cramming four subwoofers into a 13 by 13 room, but is there another way to get multiple low frequency sources into a small room?  Well, as a matter of fact there is.  You see, a dipole speaker can be thought of as two monopoles operated in opposite phase.  So in effect, a pair of dipole speaker interacts with the room as if it were four low frequency sources, from an in-room bass smoothness perspective. 

My suggestion of a speaker type that would work well in your room would be a dipole, such as Maggies, Quads, Emerald Physics, Gradient, Linkwitz, and so forth.   I'd suggest setting them up slightly asymetrically - neither square with the room, nor diagonally positioned, but somewhere in between.   You may have to diffuse the backwave energy in order to get good image depth.

It is also likely that a bipolar speaker (older Mirages, bipolar Omegas) would work well in your room, as the same principles apply.  Once again, diffusion of the backwave would probably be beneficial. 

Getting down to a specific speaker, you might want to try the Maggie MMG and see how it works in your room.  I have a friend with a cube-shaped room roughly 12 by 12 by 12 and the MMG worked well in there.  That's my suggestion.

The low-frequency peak-and-dip pattern isn't the only acoustic issue in a small room, but it's a start.  I can talk about others if you'd like.

Best of luck to you.

Duke

[DaveC113]

Hi,

I just moved into a small space, and its not as good as the old larger space was. As a temporary solution for bass issues, I put some blankets in the rear corners of the room, and this helped. What other room treatments can help a small room? I am using Omega XRS and a 10" down-firing sub.

Thanks,
Dave

[Ethan Winer]

As a temporary solution for bass issues, I put some blankets in the rear corners of the room, and this helped. What other room treatments can help a small room?

Dave, blankets are not useful for bass frequencies. You need bass traps. You can either build them or buy them, depending on how much your time is worth to you.

Start here:

http://www.ethanwiner.com/acoustics.html

There's also a lot of non-sales information - articles, videos, and downloads - on my company's web site, linked under my name below.

--Ethan

[Ethan Winer]

The ear doesn't distinctly hear every little peak and dip that you see in a frequency response curve. Rather, the ear averages out the loudness over intervals roughly one-third of an octave wide, called "critical bands".

That's true at mid and high frequencies, but below about 300 Hz you do indeed hear the effect of deep nulls, even if they're very narrow. At higher frequencies the nulls in one ear are not present at the other ear, so you still hear that frequency. But in the bass range the wavelengths are longer and a deep null is often present in both ears. If that null happens to align with a musical note currently sounding, you will not hear that note. You may hear the harmonics though, which is why nulls don't sound like a total dropout.

In most rooms, the effects of room reflections in the midrange and treble results in many narrow-band peaks and dips that usually average out over third-octave intervals.  But in the bass region, the room-reflection-induced peaks and dips are large enough and far enough apart that they stand out audibly.

Exactly. But it's important to point out that those peaks and deep nulls are different for each ear, which is why they kill imaging.

Now it sounds crazy to contemplate cramming four subwoofers into a 13 by 13 room

Indeed, especially since bass traps do a better job and cost less. Adding bass traps also reduces modal ringing, which multiple subwoofers do not.

--Ethan

[TheChairGuy]

Just a personal note regarding this.....I have a 12 x 15 x 8-12' room (somewhat irregularly shaped, with too many windows )

The (now completely modded) MMG on full stands, outboard crossovers and re-wire has never sounded right in my room.  While my room could certainly use considerably more treatment (besides thick berber rug, some egg crate foam pieces about, cloth window shades and some drapery) I believe Maggies of any size need more space than many rooms can offer.  I cannot enjoy my MMG's at a distance of 8-9 feet that I have in my room's current setup.

I'm not here to disagree with Duke, as he seems far more knowledgeable than I on acoustic matters, but my experience in the last 3 small'ish rooms that have housed my audio system has been less is more. Stand mount monitors have worked best, or small floorstanders with limited low frequency extension (my current one has some output below 50hz, but not a lot).  I owned a medium sized transmission line speaker (Terpischore, then made by Landes Audio in New Jersey) long ago in a room smaller than I have now, and it worked quite well - perhaps that's an answer for you for fuller range sound? 

Transmission line (or quarter wave) designs have tendency to excite room nodes less, I've since read. 

The ported Ellis 1801's, with those fantastic, bass rich SEAS magnesium drivers, may in fact be more than your 13 x 13' room can handle. You can certainly try absorptive panels of various types (with some aesthetic penalty, of course), but you can't push the boundaries of your walls further and it may or may not be enough for your Ellis' to co-exist peacefully in that room 

John / TCG

It is also likely that a bipolar speaker (older Mirages, bipolar Omegas) would work well in your room, as the same principles apply.  Once again, diffusion of the backwave would probably be beneficial. 

Getting down to a specific speaker, you might want to try the Maggie MMG and see how it works in your room.  I have a friend with a cube-shaped room roughly 12 by 12 by 12 and the MMG worked well in there.  That's my suggestion.

[DavidS]

Yep - beginning to think this room is an audio nightmare.  Besides being 13x13, it has 10 foot ceilings, 4 full sized windows, a full window door, restored hardwood floors, and a brick fire place.  On top of that it looks great in a 1920's fully restored way (will try and post a picture - camera is out of batteries right now) and man would I be in trouble if I started hanging foam from the walls.  I will say my Ellis' sound much happier back in the much larger living room.  Ethan and Duke I will read more about the treatment stuff but was wondering whether high efficiency speakers with lower powered amp might work better in this room.

David

[WEEZ]

What I would recommend you consider is a smaller sealed speaker. Less 'boom'. I realize that they are harder to find these days, and I don't know what your budget is, but you might have a look at www.nsmaudio.com for some ideas.

WEEZ

[bpape]

13x13 with lots of windows and a hard floor is certainly a very live, difficult room.  I'm not sure you'll have much better luck with a different speaker - sorry.  You definitely need to get the bass under control in the corners and probably something behind your head on the rear wall.

The Ellis may be too much but I wouldn't think so if the room was done properly.  Placement of seating and speakers in a room like that is also critical.  A couple inches here or there can make a ton of difference.  I'd also seriously consider a nice heavy rug between you and the speakers.

Bryan

[zybar]

HEADPHONES!!   aa

George

[macrojack]

Once again, Zybar provides the best advice. State of the Art headphones will cost less and sound better than fighting a bad room situation. Just the treatments alone will cost more than a good pair of cans and an amp to drive them. The savings might allow you to upgrade your source. A state of the art recliner is also recommended as a primary component in this system.

[Carlman]

I agree with the headphones and recliner suggestions...   However, being a non-headphone-enjoyer....

Can you add some folding wall-things?  I used an 'oriental screen' to divide my 11x13 room from a hallway.. and added foam and fabric to that... It looked pretty nice and did a good job of creating a little barrier and providing some absorption... not huge.  I agree about adding a rug... that helps a little.  Also, do something with the primary reflection points if you can.

I heard a pair of Era Design 5's yesterday and was pretty impressed.  They make a 'Design 4' that might be perfect for that room.  They don't over accentuate the highs like most monitors.  

All that said... If you have all hard surfaces, in a small cube, and aren't able to add treatments of any kind, I think you're out of luck... try another room.  Seriously, I'd give up on trying to do anything but background music... You'll just argue with your SO and get frustrated with the lack of performance. (likely from both )

-C

[Duke]

To Ethan Winer:

Thanks for your comments.

Regarding the imaging being "killed" by reflection-induced frequency response differences at the two ears, I'm not so sure. The ear/brain system derives directional cues primarily from the first .68 milliseconds (corresponding to roughly 8 inches path length) of a sound impulse.  After this, the precedence effect, or Haas effect (after Helum Haas) kicks in, suppressing directional cues from reflections of the original sound.  That being said, a strong, distinct ("specular") early reflection can still skew the apparent direction of a sound source - which is why diffusion or (if necessary) absorption of first reflection energy is desirable.   The Haas effect continues for 40 milliseconds or so (if I recall correctly), after which a reflection is distinctly heard as an echo.  During this interval the ear/brain system is still picking up timbral and loudness cues, but that's a different topic.

Research published by Todd Welti and others shows significant smoothing of in-room bass, including modal peaks and dips, from using multiple subwoofers.  I diverge from Welti's conclusions in that I advocate asymmetrical rather than symmetrical subwoofer placement, drawing on Earl Geddes as my source.  I see bass traps as definitely beneficial as long as they don't soak up too much midrange and treble energy; I don't like dead rooms.

By the way, your article entitled "Acoustic Treatment and Design for Recording Studios and Listening Rooms" is excellent.   I like your concept of having a mixture of "hard and soft" surfaces in the room, and agree that rooms should be more absorptive in the bass region than they typically are. 

Just for the record, I didn't advocate using multiple subs in that 13 by 13 room - instead, I advocated a principle that that can be applied using a pair of dipole speakers, and used the concept of multiple subs to introduce that principle.

TheChairGuy mentioned good results with a transmission line in a small room - note that a transmission line enclosure has two physically separated low frequency sources, the cone and the line terminus.  So this is in effect an application of the multiple low frequency source principle.

Dave Ellis experimented with front and rear firing ports on the 1801, and found the bass to sound tighter and more natural with the rear-firing port (I came to most of the same conclusions he did, and also use rear-firing ports).  Perhaps one reason for this is that the rear-firing port's location is different from the cone's in three dimensions (assuming some toe-in), whereas the front-firing port's location is only different in one dimension. 

To DavidS:

If the problem is too much bass in your room, you might consider lengthening the port and/or reducing its diameter, which will lower the tuning frequency.  Buy a smaller-diameter section of plastic pipe at Home Depot, cut it to desired length (I can help with the calculations if you e-mail me), and wrap it with electrical tape at one or both ends to get a snug fit in the existing port.  The result will be a shallow bass rolloff starting higher up in frequency.  In fact, if the box size is sufficient, a low-tuned reflex system's frequency response characteristic more closely mirrors typical room gain than does a sealed box's frequency response, so I would suggest you try this before switching to a sealed box speaker (which I think would not work as well in the bass region in your room as a dipole or transmission line). 

Now if you have midrange or high frequency issues in your room, those have to be addressed in some other way - probably either room treatment or loudspeaker radiation pattern control, or both. 

Duke

[WGH]

To DavidS:

If the problem is too much bass in your room, you might consider lengthening the port and/or reducing its diameter, which will lower the tuning frequency.  Buy a smaller-diameter section of plastic pipe at Home Depot, cut it to desired length (I can help with the calculations if you e-mail me), and wrap it with electrical tape at one or both ends to get a snug fit in the existing port.  The result will be a shallow bass rolloff starting higher up in frequency.  In fact, if the box size is sufficient, a low-tuned reflex system's frequency response characteristic more closely mirrors typical room gain than does a sealed box's frequency

Duke

That is exactly what I was thinking (sort of) but simpler - like "stick a sock in it" (the port that is). But then I re-read the original post and it looks like the speaker is the 1801s (not 1801's) which is the smaller sealed design. Am I correct?

[DavidS]

My speaker is stand mount 1801 with rear port.  They do lots of bass but whole sound spectrum seems to just overwhelm the room and being relatively inefficient it takes some volume and power to get them going.  They do sound great from the next room - which is the kitchen.

I am trying out a pair of small Audio Note AX2's today.  More efficient speakers, much less deep bass, more polite sounding in the room - not sure if its just different but scale seems more right for the room.  Will play around with some of the room treatment and positioning ideas and see if this makes a difference with my Ellis'.  Lots of options here including moving all the good gear back to the living room.

[Duke]

Hi DavidS,

Thanks for the additional information.

Okay, my guess is that your room is overly reflective.  While obviously you can't treat every reflective surface in the room, can you treat one of each pair of opposing surfaces?  For instance, put a tapestry on the wall opposite the windows?  You might instinctively balk at the asymmetry of this, but see my post above on the Haas effect.  Also, a physicist specializing in acoustics that I'm friends with built his dedicated listening room with one side wall of irregular rocks and the other panelling partially covered by a tapestry, and the sound he gets is superb. 

In a highly reflective environment the power response (summed omnidirectional response) dominates over the on-axis response, such that a speaker designed for smooth power response will probably sound better in such a room than a speaker designed for smooth on-axis response.  The classic example is the BBC's LS-3/5a, a mini-monitor designed for use in small, highly reflective mobile recording studios (vans packed with electronic gear).  The problem is a blooming of the loudspeaker's radiation pattern at the lower end of the tweeter's range, and the fix is a dip in the lower end of the tweeter's on-axis frequency response so that the total output in that region remains smooth when the reverberant energy is factored in.  Another beneficial approach is a loudspeaker with a well-controlled radiation pattern so that there aren't large off-axis peaks and dips to skew the power response.  Most of the speakers I carry (or build) have fairly well controlled radiation patterns, so I'm a believer in this concept for a variety of reasons. 

You mentioned high efficiency speakers.  Many high efficiency speakers have fairly well-controlled radiation patterns, and in that regard at least they'd be a step in the right direction in my opinion.  They also tend to have good liveliness even at low volume levels.  Omega comes to mind - I used to be an Omega dealer, and think very highly of the line. 

Duke