Absolutely. We aphiles nearly all try to cram too much bass into too small a room. With treatment (the room, not our neurosis!) measurement and best of all, high quality equalization for the listening position, it can be done, but it ain't a "set it and forget it" deal.
Jeff |
The first thing you need to determine is how low your sub is going to operate. Room modes occur higher 80-200 (mid-bass) region in smaller rooms. Check the internet on how to determine where room modes occur based on the distance between two walls. So it will be your main speakers that will excite room modes. The sub if it operates below 40Hz with a XO of 24dB/octave won't really cause a problem but may even help smoothen out nodes that may occur with proper placement and being a bit frugal with the sub's volume control. |
Don't know your price point but I use a small Velodyne SPL800 in a small dedicated room. It took some experimentation but after I realized the sub wasn't going in the corner things got a lot easier. I don't know how people get their subs to sound good in room corners. Click on my system page for a pic of what I mean. |
Athipaul, I may have this wrong, but doesn't frequency doubling occur with room modes? That is, a given mode will be excited by a wave at half its length?
Thanks for any help with this. |
Small rooms are the hardest to get smooth bass in. If you are really serious about getting good bass in a small room, there is a solution but I must warn you - at first glance is seems insane.
First a bit of background. You may have noticed that moving the speakers, or moving a subwoofer, changes the bass at the listening position. This is because how the low frequencies interact with the room depends not only on the room's dimensions, but also on the location of the low-frequency source(s) in relation to the room's boundaries as well as the listening position.
Using multiple subwoofers will result in smoother in-room bass because where the response of one sub is "zigging" due to its room interaction, the response of another sub is "zagging" - so the net result is smoother than any one sub could be. This isn't my original idea; I learned it from Earl Geddes, but it is also supported by Todd Welti.
"With enough subwoofers, it is theoretically possible to cancel out all modes in a room." - Todd Welti, "How Many Subwoofers are Enough". In a small room, the problem is modes that stick out like a sore thumb, and using multiple subs is the solution. Small subs though - we don't need big ones.
"The spatial variations, and to a certain extent the frequency response variations, will go down (get smoother) as 1/N, where N is the number of independent sources." - Earl Geddes, Speaker Asylum Post 10-30-05. This give us an idea of how much improvement to expect from each additional sub.
As a practical matter, Welti suggests four subs as enough to get a significant smoothing of the bass. Here is a paper he wrote on the subject:
http://www.harman.com/wp/pdf/multsubs.pdf
Whereas Welti recommends symmetrical placement of the subs, Geddes advocates asymmetrical placement:
http://www.gedlee.com/downloads/sub%20study%20.pdf
I suggest using four small subs that have a steep-slope low-pass filter (4th order, rather than the more common 2nd order) to allow greater flexibility in sub placement. If you can't hear the location of the subs, you have more freedom to experiment. I use a four-sub setup in my listening room when I'm using speakers that call for subs (like hotrodded Maggies).
Duke |
Small rooms are the hardest to get smooth bass in. If you are really serious about getting good bass in a small room, there is a solution but I must warn you - at first glance is seems insane.
First a bit of background. You may have noticed that moving the speakers, or moving a subwoofer, changes the bass at the listening position. This is because how the low frequencies interact with the room depends not only on the room's dimensions, but also on the location of the low-frequency source(s) in relation to the room's boundaries as well as the listening position.
Using multiple subwoofers will result in smoother in-room bass because where the response of one sub is "zigging" due to its room interaction, the response another sub is "zagging" - so the net result is smoother than any one sub could be. This isn't my original idea; I learned it from Earl Geddes, but it is also supported by Todd Welti.
"With enough subwoofers, it is theoretically possible to cancel out all modes in a room." - Todd Welti, "How Many Subwoofers are Enough". In a small room, the problem is modes that stick out like a sore thumb, and using multiple subs is the solution. Small subs though - we don't need big ones.
"The spatial variations, and to a certain extent the frequency response variations, will go down (get smoother) as 1/N, where N is the number of independent sources." - Earl Geddes, Speaker Asylum Post 10-30-05. This give us an idea of how much improvement to expect from each additional sub.
As a practical matter, Welti suggests four subs as enough to get a significant smoothing of the bass. Here is a paper he wrote on the subject:
http://www.harman.com/wp/pdf/multsubs.pdf
Whereas Welti recommends symmetrical placement of the subs, Geddes advocates asymmetrical placement:
http://www.gedlee.com/downloads/sub%20study%20.pdf
I suggest using four small subs that have a steep-slope low-pass filter (4th order, rather than the more common 2nd order) to allow greater flexibility in sub placement. If you can't hear the location of the subs, you have more freedom to experiment. I use a four-sub setup in my listening room when I'm using speakers that call for subs (like hotrodded Maggies).
Duke
dealer/manufacturer |
Duke offers a lot of "sound" advice. 2 subs are almost minimum, but you can sometimes get away with one sub depending on where it's crossed over and the use of a good parametric EQ. Quite often in small rooms the crossover point may be as low as 35 Hz, which may be lower than the first 1/2 wavelength of any axial mode (roughly 17 feet). Thus you really aren't exciting any of the modes in that application.
We used a Talon Thunderbird and Rives sub-PARC at RMAF and won an Audio Oasis award. This was nearly the case in that we did not really need the parametrics in the sub-PARC because we crossed over so low. |
Tobias,
Its not frequency doubling that occur with room modes but amplitude doubling or cancellation i.e peaks and dips.
Duke,
Multiple subs would only work in a large room. In a small room this would only create nodes (peaks/dips) at mid-bass and higher frequencies. So the result without any other form of control e.g EQ as suggested would be mid-bass prominence.
Samuellaudio,
Can I suggest you plot your room (Rives CD2 plus RS SPL meter) to know where you stand currently and then do it again with a sub i.e a loaner. You will then know for sure how much the sub affects the room. |
Rives, thanks for the kind words - you could so easily have accused me of double-talk!
Seriously, my apologies for the double-post. I thought I was editing (instead of double-posting), and then my connection failed and I couldn't get back online.
Duke |
Athipaul, I don't see how multiple subs in a small room "would only create nodes (peaks/dips) at mid-bass and higher frequencies".
The subs are not contributing at mid-bass and higher frequencies, so they do not "create nodes". They do smooth the in-room response in the region where they are contributing, as I will explain.
The problem in a small room is not too many room-induced peaks and dips; the problem is too few! In a large room you will have more room-induced peaks and dips bunched up closer together, and the ear tends to average them out across 1/3 octave intervals (called "critical bands) so the individual peaks and dips don't stand out - just the broader trends. In a small room, the room-induced peaks and dips are too far apart for the ear to average them out so they tend to stick out like a sore thumb. But by using multiple subs spread around in a small room (each contributing its own unique peak-and-dip pattern at any given listening position), we approximate the more dense peak-and-dip pattern that exists in a large room, and the ear's smoothing mechanism can work in our favor. I have done some simplifying in this one-paragraph explanation; you might want to take a look at Welti's paper.
Equalization is not necessarily the panacea it seems to be at first glance. Equalization can smooth the response in one listening position, but actually make it worse elsewhere in the room because the peaks and dips move around as the listening position changes, so from a different listening position the equalization may well be boosting a peak and/or cutting a dip. Multiple subs gives a more uniform response throughout the room, so that any equalization still called for will probably be beneficial throughout the room rather than in one location only.
Duke |
Lot's of good advice above (I am now inspired to add a second sub!). To relay a little personal experience, for the past couple of years I had ported monitor speakers in my 11'x 22' room. I have my setup on a short wall, which effectively requires that I use a near-field approach. I wrestled with excessive bass "boom" for some time, but after some experimentation I noticed that I could plug the ports on the monitors and control the bass very effectively. Based upon this experience, I have recently decided to go with a sealed monitor (Merlin TSM) and added a Martin Logan Dynamo (10") sealed sub. Like Timrhu, I found the corner didn't work well and I have my sub positioned just as he does in his system pics (sorry my pics are not up to date). I get great bass response with no boom - except occasionally on poorly recorded material. So, the moral of my story, you can get good bass in a small room, but I would highly recommend sealed enclosures both for the speakers and sub. Also, experiment a lot with your crossover and volume levels (get an spl meter) and fight the temptation to turn the volume levels up. The goal, I believe, is not to hear the sub per se, but rather to miss it when you turn it off. |
11 x 22--ouch. This is as bad as my office, which is 10 x 20. However, it works good for testing worst case scenarios. You will need something with a parametric and depending on the crossover point 2 subs can make a significant difference for both the peaks and nulls in your case. |
Why I like a bass horn with its one massive null. Easy to work arround this sit 8-10ft from bass horn;) But dukes got a point.Under his hat;) And is right about the swarm of subs... |
I suggest bass traps at the very least. You'll never achieve acceptable response without room treatment. As Rives said, a parametric EQ is also recommended but I would start with good quality bass traps, at least in the 4 corners of the room, add more later for even better results. |
If things are getting too exciting, try a few Vallium. that should work.
Add in a few more and setup will get pretty interesting too.
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