I have been using REL subwoofers and Maggies in combination for a long time......... I find the sound very cohesive. Maybe you hearing the wrong sub???
The panels run full range. REL subs are designed to use a signal from the power amp and re-enforce the sub-bass below the signal of the main speaker. I have mine crosed over pretty low (around 32Hz if I remember right). REL's are known for their speed and musicality...... less so for their HT type dinosaur stomping/explosions, etc.
Mrtennis...One characteristic of my system which suggests that the SW and Maggies are well integrated is that, while playing a pink noise test signal I can sweep the X/O frequency between 40 Hz to about 300 Hz without any change in the sound. When playing certain kinds of music, loud organ and the like, I push the X/O up to 300 Hz or so to get that "slam" which Maggies lack. Chamber music is down to 50 Hz. Most of the time I am at 80-100 Hz.
Eldartford describes: "sw drivers mounted in the wall behind it" SO, you're "infinitely baffling" the sw?
If so, I assume you're equalising the s/w via the Behringer - no? Have you checked for phase?
Mrtennis notes "i still tend to hear both cone and panel separately ". That's often the case. Don't forget, panels are open baffle while sw are boxes.
BTW, someone describes using an open baffle SW system to pair with stats -- but can't find it.
My experience echos that of Cmo's. Low pass set very low, 40hz., and at low volume, I can get a pretty good blend and sub bass reinforcement. When I try to use the sub to recreate the bass of 1.6's for certain types of music, (rock, alternative) it just won't blend properly. But then again, my rock is usually played at volumes high enough that the room accoustics have broken down, destroying anything approaching sound coherence.
Active crossovers in front of the amps might make playing a wider range of bass through the sub more workable with the 1.6's.
MrTennis - I have a pair of Revel B12 subs (non-ported)with my Magnepan 3.6 r's and they are completely integrated into the system. That was NOT easy to do. I spent 6 months experimenting with placement of the subs and experimenting with subwoofer interconnect length and materials. I finally settled on custom made silver cables 1.5M long (the amplifiers are 3M of cable (Nirvana SX Ltd XLR) from the pre-amp and the main speakers use 4ft of (Purist Audio Aqueous Anniversary bi-wire)speaker cable. I have access to lots of cables to try and a lot of patience to get the system sounding right. To get a sub (or subs) to seemlessly integrate with planer or panel speakers isn't easy - it takes a lot of work, but I am here to tell you it CAN be done.
Gregm...My three SW systems are "sealed enclosure" which as you probably know is not the same thing as "infinite baffle". The enclosures (which are all the world like coffins standing on end) are embedded in a wall. Their front baffles, which go floor to ceiling, are covered with acoustic foam (for the Maggie backwave). Fabric goes over the whole thing, so the SW systems are completely camouflaged.
Phasing is easily verified using my spectrum analyzer. (Out of phase produces a deep sharp notch at X/O).
I tried running Running two Velodyne DD 10's subs with built in room correction. These are awesome subs IMO very fast and dynamic. But intergrating them in my system, at that time was to big a trade off for bass. Using the high pass in the subs made the speaker and sub intergration very very good. But it made the mids and highs sound electronic.
And by not using the high pass, and just using the room correction, I could never get the seamless intergration with the main speakers which were ML Odysseys. I ended up selling the two subs and the speakers and bought a better full range speakers. The Martin Logan Summits with built in Subs. Which are every bit as good as the Velodyne Subs. Now their is no trade off.
However, if you pre amp is processor based and your using that with the 2 Velodynes DD 10's it would intergate the bass very very well.
But in an all analogue system I don't think can be done. With good results
There's a basic rule of thumb that usually works very well: Cross over the sub one octave above the -3 db of the main's low end, e.g., if you're mains are -3 db at 40 Hz, set the cross over at 80 Hz. This counters the conventional wisdom of crossing over as low as possible. I had the same problems when I persisted in crossing over low. You will need an SPL meter, test CD, and some time to get both the sub's level and phase set properly for the flattest response in your room. I was even able to tame my room's 60 hz mode. I don't buy that subs can't be integrated well with stats or panels. It takes some time and experimentation. Don't assume just because an audio store or someone you know has plowed megabucks in their system that they know how to get a sub integrated properly.
Eldartford is correct in saying you need large diameter short excursion cones.Most mainstream subs using long excursion drivers with heavy rubber surrounds are going to sound slow and smeared.They are just wrong.
I can recommend the RCF L15 /554k 15 inch woofer[superb quality Italian pro speakers] as a great driver for using with panel speakers.Put these in a 100 litre box and port to RCF recommendations and drive with any half decent subwoofer amp and you will get that extra octave of bass[33-66 hz] that many panels lack.And it will integrate superbly and be fast sounding.Also this drivers high sensitivity means something like a 100 watt sub amp is more than adequate.
A couple more possibilities:
1) Consider stereo subs. IMO, even at low X-over points, stereo subs create more realism. See the 6moons article:
Also, consider a pair of VBT/TBI subs as an option. They're small and inobtrusive and can be placed anywhere and have short excursion drivers and I've found them to integrate well with several speakers.
2) If size doesn't matter, consider a pair of dipole sube to match your dipole speakers, and place them in the plane of your Maggies.
I first realized the value in dipoles when I had a square room and big Proacs. Couldn't get the bass right with any placement. Switched to Genesis V with integrated dipole subs and the bass improved dramatically.
I'm using DIY Linkwitz Phoenix dopole subs and can't say enough good things about them.
3) Consider Tact preamp room-correction. Maybe more than you want to spend, but I've not heard anything that integrates subs with the mains as well as this. I was astonished the first time I heard it. Nice and fast digital crossovers allow you to position the subs where the bass sounds best and corrects the bumps and valleys of the bass frequencies at your listening position.
When you see the aberrant bass measurements in your room with the Tact you'll understand why so many folks abandon subs---their loss. Low frequencies add spatial cues that add so much to realism, but they have to be tamed so they don't sound out of control (and muddy up the mids). The Tact does this amazingly well.
I think that most people buy subwoofers largely by the numbers, and the numbers aren't kind to transient response optimizing designs.
Consider two subwoofers, identical in size and price. The first one is -3 dB anechoic at 40 Hz, and second one is -3 dB anechoic at 20 Hz. Which one do you think most people are going to buy?
What the numbers don't tell you is that the 40 Hz subwoofer has much better transient response than the 20 Hz one. Good transient response is expensive in terms of box size and bass extension.
I'm involved in the development of a subwoofer designed specifically to work well with Maggies, and if the project is a success it will probably be marketed through Audiogon. The design will be optimized for transient response, rather than for loudest deepest possible bass in smallest possible box.
I do not think that the surround itself is a dominant factor in the sound of a subwoofer. Rather, those subwoofers you see with the donut-like surrounds are typically optimized for loudest deepest possible bass in smallest possible box, and transient response is the casualty. The prosound 15" woofer mentioned by Jtgofish has parameters more conducive to good transient response, assuming adequate box size.
Good to hear about your plans.You are right about the surrounds too.I have always preferred cloth surrounds to rubber.
I understand that many of the RCF woofers are now back in production.
I have mounted the L15/554k in a coffee table style box[firing down].This seems to sound best in the middle of the room.The gap at the bottom is about 100mm[4 inches].
This sounds superb with ER Audio stats as well as full range point source type speakers like Lowthers etc.
Many people swear by a high pass filter on the main speakers but I have found this is not really necessary unless they go below about 50hz-which most panels struggle to do.
Good luck.There is a real need out there for this type of low bass speakers that mainstream subs fail to address.
"crossed over at 35Hz" !!
IMHO, a subwoofer that can't go higher than that, unloading the main speakers, is just as bad as one that can't go lower than 35 Hz. Sometimes audiophiles seem to get into a contest as to whose SW is crossed over lower. It reminds me of a Hoot Owl that lived at the nearby Audibon park. It would hoot back at you IF you hooted at a lower pitch. The hoot would go back and forth until the bird was as low as it could go.
I have Ribbons/Hybrid the Superslim 1800se speakers from www.ambiencespeakers.com.au and the Castle Classic Active Subwoofer, it required patience and time to get them perfectly well-integrated, seamless spectrum. I think ribbons and dynamic Sub Woofers can match perfectly well, it is a matter of adjusting and regulating. Best, Antonio Machado.
Hmmm... I know this thread is a bit old, just for others reading this and if you haven't gotten anything yet, I recommend the Hsu HO. I may have some of the problems described above but it sounds pretty darn good to me! Using test CD (Stereophile #2) and Radio Shack meter it wasn't hard at all to make it flat with some fiddling.
Try Tarzan (Phil Collins version) track 1 first minute, or Dark Side of the Moon track 1 first minute, then tracks 2 and 3... The Hsu with Magnepans will blow you away! Anyone else using these two together who thinks the Hsu is too slow? It could be, but I can't find a track where it is obvious. It just blows you away!!!! If someone thinks these aren't a great match, what is a track where I can try to detect it?
thanks for your comments re the hsu.
i have been advised to use only a rel with a panel speaker.
i have not heard the hsu with magnepans. magnepan has designed a woofer, based upon the mg 20.1, for use with other magnepans. this panel woofer goes down to 40 hz. it is not a "sub" woofer, and perhaps magnepan will design a panel driver which goes below 40 hz. if so, problem solved.
I have been using MGllla's with a Vanersteen sub for a long time. The vandy is just as fast as the maggies, if not faster. The combo is seamless with added benifit of the bass panels being cut off at 80hz, letting the middrange panels open up. Panels and subs can and do work well together, just finding a "fast enough" sub is the trick.
I used to think that the problem in trying to blend a subwoofer with a planar was primarily a transient response issue (see my post above, dating back about 15 months). Now I believe that it is primarily a room interaction issue.
By way of introduction, consider the case of a single subwoofer located somewhere along the wall in front of us. There will be one path length from the subwoofer to the listener's ears, and then there will be another path length from the subwoofer to the wall behind the listener, thence reflecting back to the listener's ears. At the frequency where the difference in these two path lengths is equal to one-half wavelength, the energy reflecting off the back wall arrives 180 degrees out-of-phase with the direct sound and the result is a cancellation notch. At the frequency where the path length difference is equal to one wavelength, the reflected energy arrives in-phase and the result is a reinforcement peak. There will be other room-interaction-induced peaks and dips from other reflection paths, and from bass standing-wave modes if the listening position is near a node or an antinode. We can re-arrange these peaks and dips somewhat by moving the subwoofer or the listening position or both, but we cannot eliminate them by placement alone.
Equalization can smoothe the response at one listening position, but may well make it worse at other locations within the room. Whether or not equalization is the right choice depends on your listening style. I will be focusing on an acoustic rather than an electronic solution.
Now note that the problem is not that there are too many of these room-induced peaks and dips; rather, the problem is that there are too few! If we had a large enough room that the peaks and dips were more plentiful and therefore averaged out over short intervals (the ear averages out the sound across roughly 1/3 octave intervals called "critical bands), we'd have subjectively much smoother bass. It is the wide spacing of room-induced peaks and dips that makes them audible and objectionable in the bass region.
Research published in the Journal of the Audio Engineering Society by Todd Welti et al indicates that spaced mulitiple low frequency sources in a room will give smoother in-room bass than a single low frequency source. Briefly, the individual peak-and-dip patterns from each distinct low frequency source is unique enough that the average of several of them is considerably smoother than any one of them could be. We might say that having spaced multiple low-frequency sources "de-correlates" the low frequency sound field, and that is desirable.
Here's a link to a Harmon paper written by Todd Welti. It's not a technical as his AES papers, and is geared towards home theater applications, but the low frequency acoustic priciples apply to two-channel reproduction as well. In case you don't feel like reading the whole thing, Welti concludes by advocating four subwoofers arranged in one of two symmetrical patterns - either in all four corners, or in all four midwall locations:
How does this apply to dipole speakers? Well, a single dipole can be thought of as two monopole speakers back-to-back separated by a baffle, with the phase of the rearward-facing monopole reversed. So we might expect a dipole speaker's in-room bass smoothness to be comparable to what we might get from four monopoles. In fact, James M. Kates wrote a paper entitled "Dipole Loudspeaker Response in Listening Rooms", which clearly shows the superior in-room bass smoothness of a dipole compared to a monopole. Many dipole owners can attest to the superior bass pitch definition of dipoles, which can be attributed to their much improved in-room smoothness.
So when we try to match up a single subwoofer with two dipole speakers, we are trying to match up systems that have significantly different in-room characteristics. And in most cases the mismatch sticks out like a sore thumb - the low bass simply does not have the same characteristics as the rest of the spectrum. Those who have tried two subwoofers with dipole speakers seem to have a much higher rate of success, as we would expect if the foregoing discussion has merit.
The approach that I advocate is to use four small subwoofers and scatter them asymmetrically around the room. The reason for the asymmetrical scattering is to generate greater dissimilarity in the respective in-room peak-and-dip patterns from the four low frequency sources. I got this idea from Earl Geddes, and use it in a commercial system with his permission. Earl did a computer simulation study comparing four asymmetrically-scattered subs against four symmetrically-placed ones, using one of Welti's recommended configurations:
One final characteristic that the subs should have for this asymmetrical scattering is a steep-slope low-pass filter, so that none of the subs will betray their location by audibly contributing up in the midbass region. Also, good dipoles like Maggies and Quads already have superbly articulate midbass and the last thing they need is a subwoofer mucking that up.
While I do build a packaged multi-sub system (specifically intended to blend well with Quads and Maggies), these basic concepts can be incorporated into a multi-sub system that anyone can assemble themselves from subwoofers that are readily available on the market. The point of this post is to indroduce a new way of thinking about the problem of integrating subwoofers with planars, focusing on room interaction instead of subwoofer transient response.
as a dealer of soundlabs, wouldn't you think the problem of integrating dissimilar drivers is one of coherence.
regardless of where and how many cones you place in a room, a cone does not sound like a ribbon, electrostat or planar magnetic driver.
magnepan has the right idea. at ces 2007, i heard a prototype magnepan woofer. coherence is not a problem with such a driver.
it would seem that the best sybwoofer for a panel is another panel, rather than a cone.
As a SoundLab dealer, for many years I believed that cones could not possibly blend well with panels.
But is it panels and cones that sound so different from one another, or is it really dipoles and monopoles?
I've spent time with maybe a dozen different dipole panel systems and a half-dozen different dipole cone systems. I'd say that dipoles tend to have very similar bass (below 80 Hz), whether produced by a panel or a cone. Maybe not identical, but very similar - close enough to blend well if done right.
What I have presented in my preceding post is a rough sketch of a technique for getting dipole-like in-room smoothness from a judicious array of four monopole subwoofers. The line-source vs point-source discrepancy can be addressed at the same time by the four-piece subwoofer system (I can explain how if you'd like).
While a dipole panel or even cone subwoofer might be the theoretically ideal solution, how much would it cost for a dipole subwoofer that will give you significant bass extension and enough headroom to keep up with Maggies driven by a powerful amplifier?
Since you raise the question of cones & panels blending and I'm arguing that it can be done if done right, I hope it's alright for me to post links to online commentary about my prototype subwoofer system, one from a Maggie owner and the other from a Quad owner. This doesn't constitute proof of course, but I think it does constitute evidence:
Let me know if you have any questions.
Although it's not really a subwoofer/ribbon combi, I feel that Apogee has managed to combine a cone/ribbon succesfully around the '90's. I'm not saying my Apoge Centaur Major is perfect - it just isn't. But the transition between woofer and ribbon is flawless, even considering they're crossed at a remarkably high 350 Hz. Apogee has done several things to achieve this. The woofer is placed in a closed enclosure, which helps transients. The centre of the woofer is on the same height as the centre of the ribbon, so the woofer is not, like for instance Martin Logan, placed under the ribbon, but beside the ribbon. That also means the woofer is placed about one metre above the floor.
So all I'm trying to point out is that it is possible to succesfully combine a cone woofer and a ribbon/planar. It's just a lot of hard work.
I became really frustrated with trying to integrate subs with Maggie 3.5R's. About 6 months of trying with Carver true subs (they were poor, slow and had horrible overhang).
I spun them off for a brutal loss and moved on.
They literally had a delay before playing and 1-2 seconds of overhang afterwards. I guess when they glued a 4 pound hunk of steel to a passive radiator to calm it down that's what you should expect.
So I went on to smaller Velodynes (can't remember the model). Mass loading and spikes helped, but still seemed far too dissimilar to be acceptable. In either case with the Carvers or Velodynes, I tried every possible combination of electronics, internal XO and external Bryston XO, low pass/high cut frequencies, running the panels high passed and full range, different cabling, etc. None were acceptable to me.
I've heard REL subs in a few situations with Maggies and they were better, but still not great. I can say that I prefer 2 subs far more than one, regardless of location and implementation. Also, generally, that smaller the sub driver, the better luck you'll have.
I really can't believe that Harry Pearson in Absound recommended 3.6's and Carvers- shockingly bad IMHO. That would have been the point I stopped listening to reviewers as any reference other than anecdotal.
Just a thought - having never experimented - but could the issue be related to dynamics? A panel is not known for punchy dynamics (typically they compress audio signals and are preferred for classical listening)
...yet most subs are evaluated on their dynamic impact.
My suggestion would be to use an adjustable audio compressor on the sub signal so the sub can work in a "balanced" way with the rest of the audio frequencies from the panel....limit the dynamic range of the sub to match the panel.
A balanced sound will be correct at a variety of listening levels/dynamic ranges rather than over a very limited range or sweetspot.
This works if we assume that the panels bass roll-off remains consistent at different volume levels (like cone speakers generally do)....if the panel roll-off is also level dependent then I can't see a way to ever achieve a proper match.
Shadorne has a great point. Another thing I found during the Maggie subwoofer debacle is that Maggies seem to be very linear in output power (or sound pressure) relative to input power from the amplifier.
Subs (and most dynamic speakers in my experience), tend to
be more logrithmic, which happens to be more like the way we hear. Not that the comparison between panels and dynamic speakers is bad, just that they are different.
That difference seems to lead to an imbalance between
panel level and sub level with different source material
and differences in recording levels and different levels in individual songs. I found myself getting driven crazy adjusting the sub volume versus panel level even within
1 song or when I changed albums. That level problem even more than the dissimilar speaker mating problem led me to give up on the process and just listen to the panels full range.
Best of luck, I hope you have better results in your quest.
An electronic crossover is helpful, but has other issues that seem to go along with it (phas and staging issues mostly).
i owned the centaur minor. as soon as i heard the first note, it sounded like two different speakers.
the problem is a lack of coherence. a ribbon midrange and cone bass create a discontinuity. i have always been able to distinguish the difference between cones and panels.
i believe i can identify a cone driver when it is combined with dissimilar driver.
it may be possible to disguise the presence of a cone if the main speaker is not crossed over to the sub. if the sub rolls off with a steep slope at say 45 hz, you may be able to blend the two driver types creating a a seamless blend for most listeners. however, an experienced listener will probably detect the presence of a cone.
personally, i will wait for magnepan to design a panel driver capable of producing frequencies below 40 hz.
Harry Pearson and RF Gumby got very, very different results with the Carver subwoofer mated to Maggies. I suspect that neither one is deaf, and that neither one is incompetent, and that neither one is dishonest.
So, what happened?
Different room acoustics is what happened. The Carver's slightly pumped-up deep bass worked well in Harry's room, but not in Gumby's.
The room's effect is huge in the bass region - hence my preference for systems that are inherently room-friendly and have a wide range of adjustability. Dipoles are inherently room-friendly in the bass region; that is, because a pair of dipoles has the inherent in-room smoothness we'd expect from four monopoles (two of which are out of phase), their bass doesn't vary as much from one room to another, nor from one location to another within a given room (except of course if you stand in the side nulls).
Mrtennis, can you tell us the price of the 40 Hz Maggie subwoofer that you heard?
Do you know if Magnepan has plans to develop a larger version? Bass comparable to the 20.1 would be nice, assuming price isn't prohibitive.
Mr T....this may be what you are looking for Emperor (Check under products for Emperor loudspeaker)
Impractical perhaps but since when has esoteric Hi-Fi been practical.
20 electrostatic "woofer" panels should get you 110 db SPL down to 20 Hz!
i called magnepan today. the woofer that i heard at ces 2007 is not in production yet. it is still a prototype.
shadorne, thanks for the reference to abraxas speakers.
i think that for now i will live with the limitations of the magnepan and not purchase a subwoofer.
hopefully the martin logan clx has "enough" bass and is not too expensive.
Thanks for the information, Mrtennis. I appreciate your taking the time to call Magnepan. You know, maybe just maybe having a reviewer interested enough to call 'em up will help push the project forward.
If you'll be at RMAF, it would be nice to see you. I'm in room 1100. Not expecting to win you over, needless to say!
I will not be exhibiting in Las Vegas in January, though I plan to ogle & schmooze so we might bump into one another in the hallway. That show is geared towards manufacturers and dealers finding one another, and frankly I'm not looking for dealers. Besides RMAF is less expensive and imho a better show.
Mr Tennis - from your post 2 above - can you give me a specific track to listen to and what exactly should one listen for to identify that the woofer and panels don't blend seamlessly? I know when they sound really bad together - but when a system is pretty tuned (and has verifiable flat response at the couch from 20 to 200 Hz) - what exactly do you listen for?
The one thing I am aware of is some localization of the bass - which is obviously undesirable - I'm still trying to dial that in. I have a 20 ft cord and need a 25 to move it an inch from where it is, so I can't play with it too much right now.
the issue is not localization of bass but rather the timbre.
i would suggest that you listen to dave grusin, "keep your eye on the shadow", on sheffield. i have a cd called PRIME CUTS, and it is track 8.
panel bass and cone bass sounds different, just midrange reproduced by a cone and a planar driver also sounds different.
I would suggest that Shefield Drum track will highlight most of the reasons panels and subwoofers don't mix. Drums are some of the hardest sounds to reproduce convincingly, although other percussion instruments (like the piano) will work well too...Dave Grusin is a good choice.
My guess is you need a critically damped subwoofer which generally means a very large motor magnet structure within a sealed box and not the usual boomy kind (known for total movie noise capability). This means the woofer goes directly to the rest position when the signal drops to zero without any overshoot or additional resonant oscillations. Remember the panel will have good transient capabilities in the sense that it has very little stored energy...
Maybe its because my panels go so low by themselves, but I can't hear a thing that you guys are talking about!! I have the 3.6s. One thing I've learned since then is that my sub is *theoretically* not optimized for use with panels, the Hsu HO w/turbo has more venting length which slows down the sound. The current Hsu, which you can buy a couple of, should match even closer. But I honestly can't hear a thing you guys are talking about. Everything sounds awesome.
Oh - on the Rel only w/Maggies - some also use Martin Logan Depth as that is designed to be fast. But consider the new Hsu, which is not ported (and therefore not slow) at all. The ULS Quad Drive - crazy fast compared to my extra-ported VTF3HOw/Turbo. i have to think that would match really well.
Is there a physics term we can compare that tells us the 'slowness' of the sound?
Another track - with crazy dynamics and bass - The Serpents Egg, Track 9 (Dead Can Dance). You can't imagine it until you hear it.
I welcome anyone in the bay area to send a note through Audiogon and come over and try and show me what we are talking about and perhaps I can hear your system.
Ah, the term is "Group Delay". I am trying to find Group Delay numbers for some of the subs. It would be great if we could get:
Electrostatic panel itself Group Delay at say 300 Hz as refernce.
Group Delay from Sanders Systems integrated sub
Group Delay from Summit X Martin Logan integrated sub
Group Delay from Martin Logan Depth Sub
Group Delay from Hsu Quad Drive ULS-15
Group Delay from Stentor III REL
Group Delay from Stentor Studio III REL
Oh - and these things should be flat to 20, if I find out they roll off at 24, 22 or even 21 then I'm crossing them off, what is the point of all of spending that much money? Mine is pretty flat to 16.
Oh - and we have to put some sort of price limit on it, wasn't there a Krell Sub that used 30 amps circuits or something?
There is a guy 'CraigSub' on other forums and he is sub-crazy (in a good way!). Maybe I can get him to figure this out :).
I may sound like a broken record here: Room analysis, PEq, felexible x-over. I've used a Velodyne SMS-1 sub controller to seamlessly integrate a pair of Velodyne SPLR 800 subs with Maggie SMGs. It took a lot of time and a lot of tweaking, but I can't hear the crossover at all. Let me emphasize, I've always loved the IDEA of hybrid speakers, but, to my ear, even the best (IMHO - Eminent Tech) have had issues with the planar/dynamic x-over.
Using the SMS room analyzer, you can easily see how dipoles differ from forward firing speakers throughout the bass. The nature of the response irregularities in panels makes integration a real challenge - but it can be done.
IMHO, the key to good sub/speaker is smooth on-axis FR around the x-over point, so I follow the following procedure:
1) Use the room analyzer to find a smoothish chunk of bass and start with a frequency in the center of this area as your x-over point. Be sure that this "smooth area" is reasonably balanced w/the rest of the spectrum. A smooth plateau at + 15db doesn't work very well. You may have to move the sub(s) around the room a bit, 'til you find a good result.
2) Flip polarity (this will usually kill the primary suckout quite effectively) to see whether + or - works better.
3) EQ around the x-over point for further smoothing.
4) EQ below the x-over for best balance of smooth vs extended deep bass response.
IME, this procedure will get excellent results from subwoofers with a dipole, unidirectional, or omni speakers (I've tried all three).
BTW - I really doubt that your choice of subwoofer model is critical - looking "fast vs. slow" isn't likely to help. IME, integration trumps sub performance. I chose the Velos because of size. There are several other models at/near their price that return far better specs (group delay for speed and distortion for clean output) and will very likely outperform them. Yet, I still get great results despite the mediocre subs I use.