Subwoofer placement

[DLS]

After a several year, covid-caused hiatus, I took my family to the Metropolitan Opera last night for the final 2022 performance of Mozart’s Le Nozze de Figaro. The performance was wonderful, most especially Ying Fang in the role of Susanna, an incredible young talent. But I write here to share a reminder that NOTHING compares to the real thing: unamplified, world class orchestra and astonishingly talented singers in a venue allowing magnificent sounds to bloom and fill the space. It got me thinking more about my system, which from the mid-range up conveys the openness and transparency of real music in real space. I’m convinced that I’ve reached where I need to in the choice of sources, cabling, pre-amp and amplifiers. The shortfall is in the very lowest registers, which are there, but unable to breathe in the same manner as the real thing. Somehow the ease of conveying the power in those low frequencies, wherein it is both heard and felt, is just so difficult to replicate at home, where space constraints simply increase the obstacles to faithful reproduction. I have to believe the signal is there, but the combination of room and speaker limitations get in the way of getting this “right.” So, I return to the question of adding a sub-woofer and the myriad choices available. The quality, speed and power must match my twenty-five year old Sonus Faber Extrema speakers. For many reasons I can’t or won’t position one along the line between or just beyond the speakers. If what I really want is the very lowest registers, and the speed of the sub is sufficient, should I not be able to place it anywhere in the room as the frequencies I want to address (20-40hz) are truly non-directional? I know this subject has been discussed in multiple forums here and I’ve read until I’m dizzy from multiple approaches, but I’ve not come across anyone who has placed a sub 15-20 feet from the stereo pair of mains. Please let me know what folks are thinking these days.

 

[schlager]

Bass in small a room is a physical issue and should be treated as such, no way around it. To get at proper subwoofer bass, it needs to be properly integrated to the main speakers and then the total bass response should be dealt with, according to the room, placement of speakers/sub and listening position.

If one is lucky, you can "eyeball" the subwoofer integration, but often it leads to suboptimal results and wrong conclusions can be made. One of them is the perception that the bass is lagging, often referred to as slow bass.

Through use of delay, gain and EQ, most of the severe bass problems can be dealt with. Most active subs has at least a phase and gain knob. But DSP is a much better tool to use.

Again "eyeballing" such problems is not optimal, you will need to measure your in-room frequency response and see how that FR is behaving over time in your room, seen in a decay plot.

Basically all severe bass problems comes down to frequency and time/decay issues.

 

[DLS]

Bass in small a room is a physical issue and should be treated as such, no way around it. To get at proper subwoofer bass, it needs to be properly integrated to the main speakers and then the total bass response should be dealt with, according to the room, placement of speakers/sub and listening position.

If one is lucky, you can "eyeball" the subwoofer integration, but often it leads to suboptimal results and wrong conclusions can be made. One of them is the perception that the bass is lagging, often referred to as slow bass.

Through use of delay, gain and EQ, most of the severe bass problems can be dealt with. Most active subs has at least a phase and gain knob. But DSP is a much better tool to use.

Again "eyeballing" such problems is not optimal, you will need to measure your in-room frequency response and see how that FR is behaving over time in your room, seen in a decay plot.

Basically all severe bass problems comes down to frequency and time/decay issues.

Thanks for the response. My room is problematic – it’s a 14x30 living room with three 4.5’ openings. What I’m after in low frequencies – below 50hz – has to do with a sense of ease, not low end punch or room pressurization so much as a complete lack of false bass. I’m sorry I don’t have a better handle on the right language to describe what I know is missing. The instrument in real space that epitomizes what I’m referring to is a tympani, but also multiple double basses in an orchestral venue.

Can you recommend what measuring devices I might consider using to get a better handle on this?

 

[MTB Vince]

For me, several decades of experimenting with one or two high-end subwoofers in four different listening spaces consistently failed to provide both effortless low frequency extension and a seamless transition to the mains. It was always the one attribute or the other and endlessly frustrating. It wasn't until about a decade ago when I moved to a four subwoofer "distributed bass array" and DSP based EQ of the subwoofers that I began making meaningful progress towards both goals.

Optimal subwoofer placement (within practical constraints) was determined iteratively using a calibrated microphone and Room EQ Wizard. Once I'd identified the best (least worst?) measuring (but still practical) locations for the four subs, I employed a Xilica pro audio DSP "loudspeaker controller" on the subwoofers to further tidy up any response peaks that the modal averaging of distributed placement had not completely addressed. The Xilica also facilitated time alignment of the front and rear subwoofer pairs at the MLP. Then two years ago the purchase of the JL Audio CR-1 subwoofer crossover proved to be the final piece of the puzzle. IMHO the CR-1 truly is the current reigning king of stereo analog subwoofer controllers. After using many over the years, the CL-1 is the first genuinely sonically transparent crossover I've come across. It also sports a *nearly unique* crossover "damping" adjustment for both the high and low pass filters that proved to be very useful when it came to perfecting the hand-off between mains and subs.

*One of Marchand's premium electronic crossover models also offers this feature. However after trying two different Marchand models over the years I was never satisfied with the transparency of their high-pass sections.

 

[stehno]

After a several year, covid-caused hiatus, I took my family to the Metropolitan Opera last night for the final 2022 performance of Mozart’s Le Nozze de Figaro. The performance was wonderful, most especially Ying Fang in the role of Susanna, an incredible young talent. But I write here to share a reminder that NOTHING compares to the real thing: unamplified, world class orchestra and astonishingly talented singers in a venue allowing magnificent sounds to bloom and fill the space. It got me thinking more about my system, which from the mid-range up conveys the openness and transparency of real music in real space. I’m convinced that I’ve reached where I need to in the choice of sources, cabling, pre-amp and amplifiers. The shortfall is in the very lowest registers, which are there, but unable to breathe in the same manner as the real thing. Somehow the ease of conveying the power in those low frequencies, wherein it is both heard and felt, is just so difficult to replicate at home, where space constraints simply increase the obstacles to faithful reproduction.

Join the club as I imagine it's a very large membership. But you should be able to achieve what you're looking for.

I have to believe the signal is there, ...

Sure it is. Well, at least it's as much there as for the other frequencies.

... but the combination of room and speaker limitations get in the way of getting this “right.”

Exactly. But again this is true for every last one of us.

So, I return to the question of adding a sub-woofer and the myriad choices available. The quality, speed and power must match my twenty-five year old Sonus Faber Extrema speakers.

I've heard nothing but good things about the Extremas. But most any reasonalbe subwoofer should easily be able to match the quality, speed, and power of perhaps any speaker. Assuming of course that the subwoofer is properly positioned and/or fine-tuned to generate a seemless integration with the Extremas.

For many reasons I can’t or won’t position one along the line between or just beyond the speakers.

Your best bet is to have the subwoofer driver's dust cap in alignment with your Extremas bass/mid driver dust cap. For example. If your Extremas bass driver dust cap is 5.5 ft out from the front wall, then so should your subwoofer's dust cap. At least as a starting point.

If your Extremas are toed-in toward the listening position then I'd ensure the subwoofer(s) follow that same toed-in angle. If you're unwilling to work with a superior starting/ending subwoofer position, it's possible you just may not be able to achieve the type of bass you're seeking.

If what I really want is the very lowest registers, and the speed of the sub is sufficient, should I not be able to place it anywhere in the room as the frequencies I want to address (20-40hz) are truly non-directional?

No. It has nothing to do with non-directional sound. Rather it has to do with standing waves, room modes, as well as a superior alignment / tuning between sub(s) and main speakers. Besides low frequencies are not as non-directional as many purport.

Also, there are many places where sub(s) should not go, including room corners. Subwoofers need space / air to breathe just like speakers.

I know this subject has been discussed in multiple forums here and I’ve read until I’m dizzy from multiple approaches, but I’ve not come across anyone who has placed a sub 15-20 feet from the stereo pair of mains. Please let me know what folks are thinking these days.

Well, this is probably as good a time as any to finalize your priorities. If a superior level of musicality for this system and room is your number 1 priority, then all other priorities must suffer including aesthetics, conveniences, etc..

I'd suggest the following steps.

1. If budget allows consider two subwoofers rather than 1. However, a finely-tuned single subwoofer should more than suffice but two does allow for even greater sonic opportunties and potentials. Then again, finely tuning a single subwoofer ain't no picnic and fine tuning 2 subs ain't no picnic and then some. Two subs is also more comforting from a symmetrically aesthetic perspective.

2. Determine the size of the sub(s). I would not entertain anything smaller than a 12" inch sub and of course 18" subs are definitely larger cabinets, etc. In my case, I settled on a single 15" subwoofer and eventually became extremely pleased with its performance after much dialing in. Last summer I intended to purchase a pair of 18" subs just to ensure I wasn't missing anything but at the last minute I chose to just purchase a 2nd sub identifical to the first.

3. Ensure the interconnects you intend to use for the subwoofer(s) are identical as the interconnects you use elsewhere in your system. Many don't do this and many don't realize that interconnects have a speed and sonic signature. So your best hope is to start off on the right foot by allowing your sub(s) the best opportunity to sonically mate with your Extremas. Integrating subwoofers to mains is a rather daunting task. Why make it more daunting?

4. Before giving subwoofers another thought, focus all of your time and attention on the Extremas' limited bass response or best level of bass musicality. This is done primarily by speaker positioning. I can't prove it but I suspect for most every room, there is a supreme position for most every speaker. Find it. It will take time but once you do, then you'll have a much better idea where you'll place your sub(s).

5. Once the sub(s) arrive, read the set-up manual about 20 times and try reading between the lines as well because as with anything we can't entirely trust that manufacturers know everything there is to know about superior bass.

6. Your speaker positions within the room should be symetrically identical to within say 1/4-inch. As should your subs if you purchase two.

There's a few more notes / cautions but the above should at least get you off on the right foot and might even get you 9/10th's of the way there. Because, like most anything worth doing in life, it all really boils down to how much due dilgence we're willing to perform.

Also, when the above steps are not taken, chances are excellent any bass from the Extremas and/or from the subwoofer(s) will sound disjointed, slow, sloppy, wooly, anemic, etc. and just plain so-so at best. Presumably, you're seeking a superior, well-defined, musical bass that goes tighter, faster, and deeper, and just plain more naturally musical.

If you've not yet chosen a subwoofer, FWIW, on a whim I purchased a $1300 Rhythmik E15 subwoofer back around 2015 and last summer I added a second E15 and I find them to be tremendously musical - once dialed in. But the E15 also has maybe 11 - 15 individual switches and knobs to better fine-tune or perhaps to better throw things outta' whack?

As for music to test with, I'd suggesting sticking with just a few music tracks that you know the bass regions with span both the sub(s) and the Extremas. If you did your homework in find a superior (or the supreme) location for the Extremas, then chances are good much of your work is already done and now you may only need to sync the sub(s) to the mains, since supposedly the mains are already synced to the room.

I'd suggest a few music pieces like this one below since much of the bass falls in the 28 - 45 Hz range and one of your primary goals is a seemless integration with your Extremas. Plus the bass is tight, quick, and overall rather well-defined. Which are exactly the same attributes you should be seeking when fine-tuing things.

 

[DLS]

Join the club as I imagine it's a very large membership. But you should be able to achieve what you're looking for.


Sure it is. Well, at least it's as much there as for the other frequencies.


Exactly. But again this is true for every last one of us.


I've heard nothing but good things about the Extremas. But most any reasonalbe subwoofer should easily be able to match the quality, speed, and power of perhaps any speaker. Assuming of course that the subwoofer is properly positioned and/or fine-tuned to generate a seemless integration with the Extremas.


Your best bet is to have the subwoofer driver's dust cap in alignment with your Extremas bass/mid driver dust cap. For example. If your Extremas bass driver dust cap is 5.5 ft out from the front wall, then so should your subwoofer's dust cap. At least as a starting point.

If your Extremas are toed-in toward the listening position then I'd ensure the subwoofer(s) follow that same toed-in angle. If you're unwilling to work with a superior starting/ending subwoofer position, it's possible you just may not be able to achieve the type of bass you're seeking.


No. It has nothing to do with non-directional sound. Rather it has to do with standing waves, room modes, as well as a superior alignment / tuning between sub(s) and main speakers. Besides low frequencies are not as non-directional as many purport.

Also, there are many places where sub(s) should not go, including room corners. Subwoofers need space / air to breathe just like speakers.


Well, this is probably as good a time as any to finalize your priorities. If a superior level of musicality for this system and room is your number 1 priority, then all other priorities must suffer including aesthetics, conveniences, etc..

I'd suggest the following steps.

1. If budget allows consider two subwoofers rather than 1. However, a finely-tuned single subwoofer should more than suffice but two does allow for even greater sonic opportunties and potentials. Then again, finely tuning a single subwoofer ain't no picnic and fine tuning 2 subs ain't no picnic and then some. Two subs is also more comforting from a symmetrically aesthetic perspective.

2. Determine the size of the sub(s). I would not entertain anything smaller than a 12" inch sub and of course 18" subs are definitely larger cabinets, etc. In my case, I settled on a single 15" subwoofer and eventually became extremely pleased with its performance after much dialing in. Last summer I intended to purchase a pair of 18" subs just to ensure I wasn't missing anything but at the last minute I chose to just purchase a 2nd sub identifical to the first.

3. Ensure the interconnects you intend to use for the subwoofer(s) are identical as the interconnects you use elsewhere in your system. Many don't do this and many don't realize that interconnects have a speed and sonic signature. So your best hope is to start off on the right foot by allowing your sub(s) the best opportunity to sonically mate with your Extremas. Integrating subwoofers to mains is a rather daunting task. Why make it more daunting?

4. Before giving subwoofers another thought, focus all of your time and attention on the Extremas' limited bass response or best level of bass musicality. This is done primarily by speaker positioning. I can't prove it but I suspect for most every room, there is a supreme position for most every speaker. Find it. It will take time but once you do, then you'll have a much better idea where you'll place your sub(s).

5. Once the sub(s) arrive, read the set-up manual about 20 times and try reading between the lines as well because as with anything we can't entirely trust that manufacturers know everything there is to know about superior bass.

6. Your speaker positions within the room should be symetrically identical to within say 1/4-inch. As should your subs if you purchase two.

There's a few more notes / cautions but the above should at least get you off on the right foot and might even get you 9/10th's of the way there. Because, like most anything worth doing in life, it all really boils down to how much due dilgence we're willing to perform.

Also, when the above steps are not taken, chances are excellent any bass from the Extremas and/or from the subwoofer(s) will sound disjointed, slow, sloppy, wooly, anemic, etc. and just plain so-so at best. Presumably, you're seeking a superior, well-defined, musical bass that goes tighter, faster, and deeper, and just plain more naturally musical.

If you've not yet chosen a subwoofer, FWIW, on a whim I purchased a $1300 Rhythmik E15 subwoofer back around 2015 and last summer I added a second E15 and I find them to be tremendously musical - once dialed in. But the E15 also has maybe 11 - 15 individual switches and knobs to better fine-tune or perhaps to better throw things outta' whack?

As for music to test with, I'd suggesting sticking with just a few music tracks that you know the bass regions with span both the sub(s) and the Extremas. If you did your homework in find a superior (or the supreme) location for the Extremas, then chances are good much of your work is already done and now you may only need to sync the sub(s) to the mains, since supposedly the mains are already synced to the room.

I'd suggest a few music pieces like this one below since much of the bass falls in the 28 - 45 Hz range and one of your primary goals is a seemless integration with your Extremas. Plus the bass is tight, quick, and overall rather well-defined. Which are exactly the same attributes you should be seeking when fine-tuing things.

Thank you so much for your thoughtful reply. While I don't have a dedicated listening room, given the WAF and a living room placement, I believe I have optimized my system. It is balanced, produces a wonderful soundstage, is extraordinarily transparent, and produces wonderful, tight and tuneful bass, whether it's from Mahler, Jennifer Warnes, or Daft Punk. My conundrum has to do with this damn obsession to get that last few percent, and that, not in relation to any rational analysis of the system per se, but only in comparison to the the Metropolitan Opera - I know, I know... this is insane and its simply not possible to get that at home, no matter what you spend on room or equipment.But I got home the other night and couldn't get that completely transparent ease of bass produced by that orchestra in that room out of my head. So I started thinking that what is missing from my system is the very lowest register, not the vast majority of bass between 80-200hz, but the stuff below 40-50hz. I posted initially to getting current thinking on reproducing this range in, which I suspect to be truly non-directional. If it is, getting one of the bigger REL subs, and placing on the other end of the room, might be able to reproduce that sense. I guess what I was thinking was that placing the sub 20+ feet from the listening position could improve the very lowest register given the length of the waveform.
In any case, no one sees to think so and I'll probably back away from spending another $5k+ just to test the theory.

 

[schlager]

As you say, you can't compare a small room in a home to a large opera scene. There is practically no standing waves or room modes in a opera scene and the decay/reflection time is so much different.

Actually you can place a subwoofer 20 feet away from your main speakers and have a nice integration in your SS. Again it's about implementation.

A UMIK-1 and REW, a pc and a soundcard will get you started. Doesn't cost much either. This is not hard to do, but there is a learning curve, which we all must climb. Ones you get the hang of taken measurements and how to interpret them, you will easily be on your way for better sound.

Placing the sub or subs in a corner, will give more headroom to the system and you will get rid off SBIR (speaker boundary interference response).

More subs is better but brings other problems to the table. Cost, where to put them, amps and a lot of cables. But it works wonderful.

Going full range with your mains SF, they can probably go down to 30 hz or so and then crossing the sub at 80 hz, will give you 3 distributed bass sources. That is enough to get rid off most severe bass problems.

If you want to take this full out, then play with Multi-Sub Optimizer freeware program. But start with REW and a microphone. There is lot of help (tutorials) on the net. Good luck!

 

[schlager]

DLS I can totally understand your confusion, because you are given very different direction pointers Focused work on things that matters, will yield results. Follow the laws of physics and you are on your way.

 

[heihei]

I'd agree with a lot of what is written above. Start with UMIK and REW and spend time with your main speaker placement to get the most even bass response. Then start playing with sub(s).

The game changer for me was using a mini-DSP unit to build a custom cross-over just for the subs (doesn't interfere with the main speaker signal). This then feeds a pair of class-D monoblocs for the Torus subs, which I can place either side of the main speakers. I'd love the ability to move the custom filter into an analogue set up some day, but not sure how achievable that is.