Best place to put a single subwoofer?

Hello Fellow Audiogoners, been out of town for a few days, just rolled in at 10:00pm (P.S.T.) from a concert at the ORACLE Arena in Oakland, California. Mrdecibel, no new developments or news to report as of yet. Probably do some experiments n' stuff this weekend. Despite the fact that I think I have done alot/exhausted all the options...there is SO much good stuff here! Much of it worthy of my efforts and full attention. Several of you have offered me help and input far beyond what I would ever have imagined! Thank you all. I have had several direct emails from folks (who haven't even participated in this discussion), and Mrdecibel I WILL be emailing you- for sure. I definately want to gleen more input from you. So far good stuff. Very informative indeed. Stay posted folks. Something WILL happen. I will get to the bottom of this bass "situation" with all yer help. Then I'll have a big party and invite everybody over for beer, cigars , and music listening! You think I'm bullshitting right? I'm not. Love to share the joy with everybody!

My best 2-channel placement was located after I placed large carpet sliders under my SVS Ultra 13 with an adequate length of cable to reach all possible locations. Sliders made it very easy to relocate and re-evaluate the responce.

All the routinely recommended locations were tested. I found one position 4 feet outward from my left main to sound best. Both mains (sealed) and the Ultra are nearly against the walls. A REL also sounded best in the same spot by far. This location was definately best for my room design.

When I tested it 4 feet from the opposite right main, it wasn't nearly as musical, tight and precise after readjusting the set-up.

A side note: I run my Ultra in the sealed mode for 2-channel to minimize port noise, performing somewhat like a rumble filter. The sealed mode helps minimize low frequency artifact from different sources, too.

Sthomas12321. FYI . This sub question was for a dedicated 2 channel music system, as indicated in the op. Thank you

Under the center channel! It will blend PERFECTLY!

Martinmobile, anything new to report ?

Martinmobile, microphonics are the result of unwanted vibrations via acoustic (airborn) or mechanical feedback, usually re-amplified through the system. These can enter (or exist in) the preamp chassis and screw things up. IME tubes are more prone to this, although, it is everywhere and in everything. I believe heavily in "tube dampers", as I feel the sound is cleaner and tighter. BAT might have included them with the pre amp. They look like garden hose washers (as an example) and come in different shapes, sizes and colors. There are so many tweaks available to "tighten" up the sound. You are free to email me and I can discuss some of these with you. Taking panels off the speaker wall would be an experiment to see if " slam" is increased (brightness too, unfortunately). Let me know. MrD.

Hello Everybody. Hello MrD, Thanks for the feedback. I am not rolling off the last octave and I am in fact running the MBL's full range. I am not a big fan of routing the audio signal through Hi-pass filters in the subs crossover. I have found that to degrade the sound to the main speakers, in my experience, so I run my sub straight from my preamp, X'd-over at between 50 and 65hz. My MBL's run full range. (I did the same thing with the Martin Logans and the plethora of subs that I mated with them. Allways full range).
I agree about the running of stereo subs as I have indeed done that. Dual Velodynes, Dual Bagend Infrasub 18's, Dual Von Schweikerts, and even Dual Sunfire "True" Subwoofers-God forbid! (which by the way were absolute pieces of shit for music. I refer to them as "nuclear bombs in a small box"- No pitch definition, 1 note bass pieces of poop that they were!). Yes it is difficult to make a pair of stereo subs integrate properly, and does not take much to overdrive the hell out of the listening room.
I have given some thought to the fact that maybe I "over-damped" the wall with all those big panels I had made, and have considered taking a few of them down, like maybe 2 of them. Leave 3 up? But I have not done that yet. The one thing I am mindful of is how much that wall behind my MBL's reinforces the sound, making the overall musical presentation rather "bright" and "strident" sounding. Not a good thing IMHO. Been there, done that, didn't really like the effect. Room definately sounds better with a "dead" wall behind the speakers. But I should try taking a FEW of them down and see what the effect is. Good suggestion MrD.
As for the tubes in my preamp going "microphonic"?? I haven't a clue. How would I know? What is "microphonic" anyway? (showing my tube ignorance now. This B.A.T. preamp is the first AND only piece of tube gear that I've ever owned. Always had solid state my whole life.) I have heard the term "microphonic" used, but wouldn't know if something like it is occuring with my toys. Please enlighten me if you would?

Martinmobile, imo/ime, all seems in order, except for two things. Because of the omni pattern of the MBLs, much is being absorbed by your panels, although I do tend to like a "dead" wall behind the speakers. As an experiment, try removing some to see if the slam comes back, even though the brightness will return. Second, the level of your equipment deserves a second sub. Room coupling is always better balanced with a pair, ime. However, as I stated, getting the "right" subs to match the mains (coherence, speed, tone, etc.)is a bitch, and much harder as the system gets more "refined". This is why many people (Audiogon type) do not like subs. Much of the "slam" you are looking for is above the subs crossover point, so it might not be the sub issue. Are you running the MBLs full range, or rolling them off at the last octave ?(again, very tricky if you are). I am not one to think the BAT gear to be the most "ballsy", ime, but your amps are great none the less. Are your tubes (pre amp) experiencing microphonics ? I would love to listen to your system, as I am huge MBL fan (although I own horns, which is another thread altogether). Keep us posted. MrD

MrD, no offense taken. At this point in time I am sponge and I am open to all input, suggestions, questions.
My system is as follows, (and is a mulligan stew of stuff):
Amps: B.A.T. Vk600se monoblocks (solid state) 600w/4ohm
Preamp: B.A.T. Vk51se (tubed)
Digital: Theta Digital Carmen 2 transport
Theta Digital DSpro Gen.5a dac
Analog: Linn Sondek LP12 w/Akito arm & Linn Adikt m.m.
PS Audio GCPH (solid state) Phono pre
F.M.: Magnum Dynalab MD102 tuner
Magnum Dynalab MD205 "signal sleuth" f.m. amp.
Speakers:MBL 101e Mk2's
Sub: JM Lab/Focal Utopia (Berrillium series)
Cables: All sorts of different shit. AudioQuest,Nordost,
Cardas,AcousticZen,Transparent. Some of it older
versions, but all of it either reference caliber
and/or top of the line in their respective brand.
(too many to list, too many to remember)

I have 5 dedicated 20amp circuits, 2 for the front end, 1 each for the B.A.T. amps., and 1 for the Subwoofer

The custom wall panels are 24"wide x 8feet tall x 3"thick (the frames that is). They are stuffed with "auralex-type" open cell foam that is 2" thick, then wrapped in in 1/2" thick batt insulation. The panels are then covered in a loose, open weave wool/polyester fabric. (Gotta look pretty for the wife. WAF is super important right?)

As for SPL's I am trying to "achieve"? Not particularly interested in any such maximum SPL's. Just want it CLEAN. And it is. Using my "hokey" little Radio Shack sound meter, it is entirely possible to reach a continuous 100db. NOT that I sit in the room and subject myself, or others to that for any length of time. But it will play loud as hell, as would be expected for MBL's. I have actually seen the spl meter hit 108 to 110db peaks. I know, friggin' crazy huh? (I don't know how entirely accurate a $35.00 Radio Shack meter is, but the sound pressure in the room is devastatingly "unbearable" at those extremes).
To reiterate my thoughts from earlier- it's really quite good. NO, actually it sounds KILLER. Just not KILLER enough, at least where bass is concerned.

Martinmobile, what is the rest of your system ?, amp/equipment, etc. My experience with MBLs have always been with Krell monos, and, a Crown Macro Reference. They love lots of power and lots of current, especially at a louder volume. I am not sure what spls you are trying to get, but you should use you Radio Shack meter and find out. Maybe you are taxing the MBL's to beyond their limit of staying clean and controlled. What are the panels you had built made of. They might be sucking out some of the bass punch and slam. Do you have dedicated outlets for your amps/equipment ? This all makes a huge impact (no pun intended) on what you are looking to achieve. I also want to add that sub woofer matching and set up is one of the hardest things I have encountered in all my years in this hobby. No offense meant in anything I have stated. MrD

You folks are all great! Thanks so much for all the input. Now my head is SPINNING! Oh where to start? Sounds like I have a few projects that lie ahead. In response to Mrdecibels input- I used to have stereo subs, (Von Schweikert Towers of power), And they DID mate very well with my Martin Logan Quest z's, but they didn't have that hard hitting "slam" factor I love. I suspect the MBL's would overshadow them alot. I have since sold the VS subs.
I HAVE given consideration to selling my JM Lab/Focal Utopia sub and perhaps replacing it with a couple of JL Audio subs. However, I want to optimize what I already have. I want to arrive at some type of solution to my current situation...and not just throw MORE MONEY at the problem, or buy more stuff. I have done that already. Gone through subs like Charmin toilet paper (15 different subs owned, and sold in the last 15 years). Don't get me wrong, my sound is KILLER right now. I just know it can be better. It's that never-ending Audiophile quest to improve what we hear. Kinda like a drug addiction if you will. I know there are many variables here, and I recognize the differences between MY system, and those that MBL sets up in hotel rooms at CES each year. The 101e's absolutely slam. The bass is powerful and punchy. I LOVE that stuff. My bass is....NOT SO MUCH. Kind of "lacking" in authority. A bit "soft" if you all know what I am getting at? So I have been disappointed. I am clearly looking for a much higher leval of quality in the bottom end.
I do not have any testing equipment, or room equilization software. Not yet. I do have one of those cheapo Radio Shack sound leval meters-works alright I guess? I have in fact moved my sub all around the friggin' room, and discovered where NOT to put it, (cause it integrates like shit). Maybe my listening room is too small? Maybe I have "over damped" it with sound absorbtion stuff? Maybe my expectations are too high? Nah! that's not it. Things can ALWAYS be better.
I will no doubt continue to try and improve upon what I already have. Anybody want to come hang out for the weekend? I'll buy the beer! I have some great Scotch and fine cigars too. I'll order pizzas and you can impart your Audiophile wisdom upon me, help tweak my set up, and then lounge around all weekend long and listen to tons of great music! No shit! I would do that. The learning experience continues. Thanks everybody for all your advice and input so far!

Hello,

For a single sub in a 2 channel setup the proper position is between the L/R speaker center front.

regards ,

For high end 2 channel systems, my experiences have always lead me to a pair of matching subs, as opposed to one, set up equally from the listening position as are the mains. Of course, serious time and tweaking are expected for good to excellent results.

A friend of mine read in the book 'Get Better Sound', that the best location is just in front of the speakers, in-between them, for a single sub. I moved mine there from the wall, and will never move it back. Blends so much better!

I'm not an expert, just know what sounds good in my room. Give all the ideas a try and see what works for you.

Rule of thumb. Place on left or right hand side of listener against the wall. Position sub 4 to 6 feet in front of main speakers. I find this position tends to help fill in any suckouts left by the mains and room modes.

Your best approach, however, would be to take some measurements to confirm what is going in with your room modes.

The first thing to learn about bass is that if it is consistently big, impressive and heavy then Houston you have a problem - your bass is crap.

IME, the two simplest and most effective techniques for subwoofer placement that require no equipment other than a SPL meter are:

(1)

1. Place the sub at the listening position.
2. Walk around the room and listening for the location where the bass is *consistent* across low frequencies. You can do this by ear or with an SPL meter.
3. Once you find the location in the room that has the smoothest frequency response (by ear or meter), place the sub in that location.

(2)

1. Flip the polarity of either the sub or the mains (but not both).
2. Play a test tone at the crossover frequency.
3. Use an SPL meter to measure the output level.
4. Adjust the sub position (or digital delay, if you have that capability) until you MINIMIZE the SPL at the listening position.
5. When the sub is in place, flip the polarity back so that the sub and the mains are the same polarity.

IME, it is usually best to find the general placement with procedure (1) and then go on to make fine adjustments with procedure (2).

The only caveat I would make about the above procedures is that neither one guarantees that the sub will be time aligned with the mains, and IMO, the best subwoofer setups are time aligned. But this is a controversial opinion. If you are interested in subwoofer time alignment, you can read about it in this thread. If that's too much information, then just following the procedures above should get you in pretty good shape.

Good luck.

Bryon

Oops! Forgot the first step before moving it around: adjust its phase to match the mains first. Final position then adjust the volume and cross-over to best integrate with your mains. You may still need to adjust the phase again.

Were I placing only one I would start out near middle of the room (though not exact, but off by a foot ot two) near against a side wall. Then take measurements at the seat, moving the sub up/down the wall length up to a few feet one way and the other at one inch increments searching for best room integration. And if not getting desired effect then up to six or eight inches further away from the side wall at one inch increments, again going up/down the length a up to a few feet.

Martin,

Your speculation about suckouts (due to room interaction) seems like a good place to start. Given the low end capabilities of the gear that you're using, I'd guess that room issues are the most likely cause of your disatsifaction with the low end performance of your system.

It's possible that you can position a single sub to address such problems, but that's a time consuming porocess of trial and error, and there's no guarantee that any position will provide a satisfactroy result. However, life is easier when you have the right tools. Either a stand alone RTA unit (like Room Wizard) or a RTA sub-woofer manager (like the Velodyne SMS-1 or Audyssey SVS) will provide a visual readout of in-room bass response. IME, this assistance will cut the effort significantly .

Or, you might see if you can find a dealer who'll allow you to do an in-home demo of any high quality HT pre-pro equipped with Audyssey (or similar) digital room correction. Substitute the pre-pro into your system in place of your existing pre-amp and A-B the system with Audyssey in and out of the loop. If Audyssey fixes the problem to your satisfaction, you can then proceed with whichever Digital Room Correction system best fits your preferences. There are a bunch of different DRC units available for you to choose from.

Just one more way to skin this particular cat.

Good Luck.

Marty

Shadorne, What? A singles bar? WTF?

A singles bar ?

Great feedback everybody. I agree about the corner placement being "overpowering". I have done that already and found that room boundries do boost the bass, but not in the best way, and the left side of my listening room where the sub was situated, was bass "heavy" despite the fact that bass below 100hz is supposed to be non-directional. I never set the crossover above 60hz and still it dominated the left side of the room. So I moved it inbetween my speakers. I have spent months pulling away from, and pushing it back toward the wall. Not sure if closer, or further away from wall matters. Doesn't seem to make too much difference. Currently x'd-over at 65hz. Spiked as well using 2 inch spikes.
Meiwan suggested 6 inches or so slightly BACK from the face of the main speakers. I have done that and can't be sure it made any difference.
A few more specifics: Sub is a JM LAB/Focal (Berrillium series) "UTOPIA". It has a 1000w. "bash" amp built in, a single, forward firing 16 inch driver, and is ported at the rear of the cabinet (transmission line I believe it's called). I am running it in balanced xlr mode. Not using the LFE input, but the L/R stereo inputs (summed bass??). My wall behind the speakers & S.W. are acoustically treated. 5 floor to ceiling absorption panels populate the ENTIRE wall. MBL radialstrahlers as you all know, have HUGE amounts of output in all directions, which made my wall VERY "live" and reflective. The sound was BRIGHT as hell. So I had panels built to "tame" it. Things are wonderful now. BUT. And that's a big BUT, it appears that my bass impact is suffering. Or does what I did to the wall not have as big a bearing than placement? This is why I struggle, and why I have turned to fellow Audiogoners for input and advice. So far alot of good advice given. Most of it I have already done before. So what do you folks think is REALLY going on? Is my JM LAB sub a piece of shit? Might I be better suited with 2 subs, instead of just 1? Run in stereo? Or do you think that my MBL's might just be overshadowing/outperforming my current sub?
I know I have posed a number of questions for your kind consideration, advice. But I am in sort of a quandry about this, and have (obviously) spent a fair amount of money on my system, and still I can't achieve the leval of "punch" and "slam" that I experience at C.E.S. in the MBL room. And they aren't even using a subwoofer. Ok, so that's what the meat of the matter is. More input please!

Try moving the chair you sit in and put the sub there. Then walk on your knees around the room with your head at about the same hight as you would be in your seat. Find where the sub sounds best to you and that is where you put it. There can be more than one locations so if you do not like the first place move around the room till you find another. I liked the location that had the tightest bass but not the lowest.
In a corner you will usually have the most bass. But it can be over powering with no detail or good decay and also hard to intergrate with your system correctly.

3 things:
1-Spikes should get you more bang regardless of where you put it, maybe even a sandbag on top of it.

2-Someone taught me a long time ago that if you don't have test equipment, a great way to find the best position is to start with the sub where it is and crawl around on the floor. Where ever in the room you hear the best bass, try moving the sub to that position.

3-Bass is power hungry. If you can adjust the crossover to a lower frequency, ie from 60hz to 40hz, you will maximize the sub's ability to apply the power where you need it most. On the other hand, if you are running it full frequency, try crossing it over at 60hz or so. Why waste it's power reproducing what the MBL's can do so easily.

My understanding is that the sub has to be set slightly behind the main speakers. I place mine beside the right speaker 6 inches or so back. Integrates very well. Centred between the 2 would be even better.

If you are having issues, it's likely the room or the sub itself - or the sub setting, many people volume the sub too high thinking it will give 'more' bass but instead it muddies everything.

Putting a sub in a corner, even if lifted off the floor, will result in maximal excitation of the major room modes. You will get maximum level output but it will be highly irregular and vary with listening position. This position is good only if you have some electronic equalization for those modes.

I checked out the book titled The Complete Guide To Hifi volume 4 at my local library . In it it suggested placing a sub as close to your listening position as possible in a 2 channel system. Corners are for home theater. Worked great when i had a sub in my system. I recommend checking that book out .

Experiment some and put it where it sounds best to you. After all, you are the one listening to it.

I have always put a single sub in the corner of the room on a stand. Depending on the sub if you can get it off the floor the better it will be. Also in the corner place it at a 45 degree angle