Searching for matching(?) Subwoofer solution

They are the 5s, I missed that. Are the enclosures closed in the back?
You certainly to need subs with those. If you could answer my other questions?

I use my office set up for only music and not HT.

mijostyn -
They are sealed cabinets. Not sure about if they are dipoles. Hardwood floors. Speakers are about a foot from the walls and about 6 feet apart.
Rocket 88 speaker cables.
I am in Reading. Are you close by?

Thanks to rauliruegas for the great resource and to bdp24 on the Rythmik suggestion.

Tim and millercarbon - Thanks for your explanations. Things are starting to become more clear to me.

Looks like I still have quite a bit of (enjoyable!) homework to do before making a purchase.

Hans

Hello Hans,
     I thought you might like a description of what bass performance to expect in your office by adding between one and four subs.  This is all based on my personal experience in my 23' x 16' x 8' room and my system but I believe these results are attainable in virtually any room, system and with any pair of main speakers utilized.
      I've discovered that one sub is able to provide good bass performance at a single designated listening seat if located properly utilizing the 'crawl' method but you may find it difficult, depending on the main speakers utilized, to configure it so that the bass seamlessly blends with the sound performance of your main speakers' reproducing the mid-bass or midrange on up to the treble. The bass may sound as if it's lagging behind and/or disconnected from your main speakers, especially on fast, smooth and detailed speakers such as electrostatic and planar-magnetic panels. I don't know much about your Olege speakers so I'm not certain if they're fast, smooth and detailed enough to cause integrating seamlessly with a single sub an issue.
    I understand most individuals would prefer to buy a single top-notch sub and be done with it but, unfortunately, the truth is that attaining good in-room bass response is not that simple no matter the price or quality of the single sub. The reason this is true really has more to do with the quantity of subs in a given room and how they're positioned, than the quality of the subs utilized. Better quality of subs never degrades from good bass performance, it's just not as important as most would assume. I'll try to explain why.
      Two properly positioned and configured subs in a given room typically provides bass response at a designated listening seat that's approximately twice the quality level of utilizing a single sub. Two subs provide increased bass output capacity and impact as well as increased bass dynamics due to the sharing of total bass requirements between two subs operating well within their limits and stress free with ample power reserves for sudden bass output dynamic demands.
    Psychoacoustic principles also begin to be applied beginning with the use of two subs in any given room that results in the bass being perceived as smoother, more detailed and better integrated with the main speakers.  
    To understand how this psychoacoustic process works, it's important to understand how bass soundwaves behave in a room with a single sub. Soundwaves increase in length as the frequency decreases and deep bass tone soundwaves are very long. A full cycle soundwave of a 20 Hz deep bass tone is 56' long, a 30 Hz is 36', a 40 Hz is 28' and a 50 Hz is 23'. For reference, a full cycle soundwave of a 20,000 Hz high treble tone is a fraction of an inch long. This mainly explains why humans are easily able to determine the originating source location (localization) of the shorter soundwave and higher frequency tones above about 80 Hz and are unable to do so on the longer soundwave and lower frequency tones below about 80 Hz.
    It's also important to know three facts:
1. Our brains can't even process the presence of a deep bass tone until the full cycle soundwave exists in the room and our ears have inputted this information into the brain.
2. Our brains require the input of at least three full cycle bass tone soundwaves before we're able to recognize a change in bass volume and pitch.
3. Our brains cannot localize deep bass tones (detect where the sounds are coming from) with frequencies below about 80 Hz.
    With the deep bass soundwaves being longer than any room dimension in many individuals' rooms, this means the soundwave will leave the single sub and need to travel as far as it can in the room and then reflect off the first room boundary (floor, ceiling or wall) it meets then keep traveling in the reflected direction until it meets the next room boundary. This process continues until the soundwave runs out of energy and with each subsequent bass tone launched into the room by the single sub. 
     These numerous bass soundwaves of various frequencies launched into the room by the single sub, and reflecting off room boundaries, inevitably run into each other at various angles causing what are called a Bass Room Mode at each specific room location at which they meet or collide. Depending on the specific angle at which the soundwaves meet, we perceive these bass room modes at specific spots in the room as either a bass overemphasis (bass peak), a bass attenuation (bass dip) or even a bass cancelation (bass null). The result is an overall perception of the bass from a single sub as uneven, not detailed, somewhat disconnected and not natural.
    However, when a second sub is properly deployed and positioned in the room, the very interesting and useful principles of psychoacoustics (how our brains process sound and our perceptions of it) begin to come into play, which results in a perception that the bass is smoother, more detailed, better integrated with the main speakers and more natural or realistic.
      Unexpectedly, this is accomplished through the second sub actually significantly increasing the number of bass room modes (bass peaks, dips and nulls) in the room. Our brains naturally and fortunately process the presence of multiple bass soundwaves below 80 Hz, by adding them together by frequency and averaging them out. This results in fewer bass modes being perceived in the room and a perception overall that the bass is smoother, more detailed, better blended with the main speakers and more natural.  
    Acoustical experts, such as Dr. Earl Geddes, Dr. Floyd Toole and others, have proven scientifically that in-room bass performance perception improves as more subs are added to virtually any given room, beginning with two subs and with improvements continuing up to the theoretical limits. Of course, there's a practical limit to the acceptable number of subs in a domestic room.
    I'm fairly certain the exact number of subs considered acceptable in a domestic room is higher for most men than most women but, interestingly, the scientists found significant bass performance perception gains were attained with each additional sub up to four but smaller more marginal gains were attained with each additional sub beyond four.
     Three properly positioned and configured subs in a given room typically provides bass response at a designated listening seat that's approaching the optimum quality level attainable at a single listening position. Three subs provide even further increased bass output capacity and impact as well as further increased bass dynamics due to the sharing of total bass requirements between three subs operating well within their limits and stress free with very large power reserves for sudden bass output dynamic demands.
     Psychoacoustic principles are more strongly applied with the use of three subs, as opposed to two subs, in any given room that results in the bass being perceived as even smoother, more detailed and better integrated with the main speakers.  
    My opinion is that the SVS SB-1000 (a small sealed sub with bass extension down to 24 Hz) and the PB-1000 (a slightly larger ported sub with bass extension down to 19 Hz) subs are ideal for utilizing in two and three sub bass systems because they're both very good quality, are relatively small, have all the necessary features/controls and are currently great bargains at about $500/each (slightly more for gloss black or white finishes).
    The larger and more expensive Olege,Seaton, Rhythmik, HSU and JL Audio subs may be better subs with more features but, remember, the critical factor for in-room bass performance is the quantity of subs used in the room and the quality and features of each is much less important. Besides, the reality is they're all high quality subs and room correction is not required for optimum performance on bass systems utilizing two or more subs.  
      However, if you prefer the best in-room bass performance, the Audio Kinesis 4-sub Swarm distributed bass array (DBA) system is definitely the ultimate bass system that I'm aware of. This is a complete $2,800 kit that includes four 4 ohm unamplified subs that are each 1' x 1' x 23", weigh 44lbs and have a 10" aluminum long-throw driver and a 1,000 watt class AB amplifier/controller that powers all four subs and controls the volume, crossover frequency and phase of all as a group.  
The use of a 4-sub DBA system will provide near state of the art bass performance not only at a single listening position but throughout the entire room. This is very useful if you have multiple seating positions in your room and prefer having very good audio at each position for both music and HT.
    Of course, only the designated listening position will be optimized for bass, midrange and treble response along with stereo imaging but very good full-range audio will still be provided at each seating position.
    They're also other benefits of the 4-sub Swarm DBA system. Absolutely no bass room treatments are necessary. You'd just need to incorporate room treatments for the midrange and treble response on your main speakers (first reflection points on each side wall and possibly some treatment on the front and rear walls). And these subs look very stylish in the room, kind of like hi-end wooden art gallery pedestals, since the 10" drivers face towards the nearest wall and have connections hidden on the bottom so all that's visible is three wood sides and the top in the wood of your choice. My wife usually has a small vase with fresh flowers sitting on one of the two that are visible in my room. They also make good end tables since they're an ideal height of 23 inches.  
    You also have the option of creating your own custom 3 or 4-sub DBA system, rather than using the complete Swarm system, by utilizing three to four SVS SB-1000 or PB-1000 subs at $499 each, or any three to four subs you'd like. I also believe adding one or two PB-1000 subs (that extend down a bit further than the SB-1000's 24 Hz to about 20 Hz) to your system would extend the perceived bass in your room down to about 20 Hz.
    The only down side of using a custom 3-4 sub DBA system is that you need to configure the volume, crossover frequency and phase settings individually for each of any self-amplified subs used rather than once for all four subs as a group on the Swarm system.
    As I've stated, I use the 4-sub A K Swarm system in a 23'x16'x8' room with Magnepan main speakers and it works like a charm. But, while I haven't personally tried it to verify, I believe three subs would perform nearly as well, especially at a single designated listening seat.

Hope this helped you a bit,
                Tim

Dear @bdp24 : I have to say that never had the opportunity to listen the
Rythmik subwoofers but I like that are servo controled and the manufacturer has a lot of models.

As any other audio items the manufacturers of subwoofers build and put in the market for sale at a very carefully choosed price point for a specific market segment.

Any audio item designed in specific at a market price point comes with the respective quality level performance. Not all " similar " subwoofers comes with the same quality level performance.

In my case quality level resolution with very low distortion levels is a main subwoofer characteristics because I use it for two channels listen MUSIC only inside a system very hard tunned to very high resolution with very very low room/distortions.

Normally with subs what we pay for is what we get on quality level performance.

Example: https://systems.audiogon.com/systems/615

do you think that the owner of this two channels room/system could " live " with 2-4 or what ever number of subs you name it of Rythmik subwoofers/DBs instead those self powered/active subwoofers towers that can go down to 3hz with almost no distortion levels at full power?

Certainly not no matters what.

If the name of the game on each one of us room/system is Quality then we have to pay for ( obviously not of what offers that dream link system. ), especially if we are talking of two channel system for listen MUSIC.

But even at your price point or my price point there are differences in the quality level of subwoofers and we have to understand that fact.

Some of the gentlemans that post in this forum and that posted here always recomend the same kind of subs and the same number of susbs no matters what: it’s a no-sense advice because there are many things to take in count that are importan to the different OP needs that we must know before give any advice. With all respect to them seems to me that their attitude is not a human been one but a " robotic " one.

Of course that we are in a free world and we can say whatever we want, it’s our privilege to do it.

Btw, @leeid if your subs are to listen MUSIC then you need only two of them and this is a very good offer and alternative for you:

https://www.audiogon.com/listings/lis9a30g-velodyne-subwoofers-dd-12-subwoofers-2-pair-near-san-subwoofers

its THD at 120dbs is only 0.5% ! ! ! . Well, my subs came from Velodyne too and I know exactly what I’m talking about but as any thing in audio is only an opinion and could be wrong.. Who knows? The best opinion is yours that will be the gentleman whom will live with what you decide: 1 or 2-4-6 subs. What you decide is important only to you.

lways is difficult to understnd and talk about subwoofers subject and as you said needs a lot of homework for a newcomer, well maybe not a lot. My advise is that first try to define your priorities at the MUSIC/sound quality level.

Quality level for you could means something different for other gentleman depends of each one of us live MUSIC experiences, what we like and the best way to enjoy it.

Good luck with your quest/hunt and enjoy it, always is a learning lesson.

R.

I am going to suggest something different than the distributed array given the size of your room. Tim (Noble 100) will undoubtedly have a meltdown, as he is a member of the distributed array church and no others are allowed to suggest there is any other way to add subwoofers to a system. With that disclaimer, here are my thoughts:

1) Your room has a good distribution of nodes, with your major bass nodes at 40 & 47 hz, followed by 70 and 80hz. In the case of your 40& 47 hz, they are located immediately against the walls, an unlikely seating position.
2) One failure in Tim’s analysis of rooms is that while a distributed bass array is better at providing more uniform bass throughout a room, for a single seating position, you can virtually always get as good of response with two subwoofers. He seemingly ignores that it is the literature he relies on for the basis of his belief of a distributed array that also studied a single listening position.

3) Run an active crossover to relieve those 5" drivers in your main speaker from bass duties. By reproducing deeper bass, especially as the volume level increases, the driver will experience increased distortion. Marchand Acoustics builds some excellent active crossovers.

4) I would use 2 Rythmik F12 subwoofers (or even due to your room size two F8 Rythmiks) which have a built in single band parametric EQ’s that can address if you still have any issue with you 40&47 hz nodes after careful setup.

5) Setup, Setup, Setup- Spend time getting the subs setup. You will need to place each carefully and phase each to integrate with your main speakers. There are many guides on how to do this. I personally suggest using Room EQ (free) with a calibrated microphone ($60-80) as you can run sweeps and see what is going on in seconds and the effect of any adjustment. It makes placement and phasing much faster.

All in this puts you at $2,500 for excellent sounding subs that will blend in perfectly with your mains.