What do you guys think of adding a subwoofer to this system?

Yes, you need a sub.

The tapered vaulted ceiling is a nice touch. You could go either end one is going to sound different from the other. I use GRs OB servos, they use Rhymik's modified (per app) plates. The issue with either company. There are supply problems with some of the plates.

But if you want a very fine complement to your existing system, servo is really the best. Decouple your speakers and do the same with any speakers you use. No spikes. Spring, Pods, or air ride.. It also add a perfect start for a TT. They actually address driver pumping with built in rumble filters and a few other goodies.

Regards

You are certainly a prime candidate.  Just do it right.  Use a sound meter app and white noise to get it integrated initially then tune from there with various music. 

Use a pair of subs. e.g. REL 7x/9x at $2200/$3000 a pair.

Definitely get two subs — the difference will be substantial. 

+1 for two subs.

At least two subs. 

Get an active sub or two, and use them just to augment the bottom octave. Don’t feature them. Keep the gain low enough so that you barely notice them, and set the low pass frequency at its lowest frequency setting. I prefer to drive subs using the speaker output connected to the high level inputs.   Work on placement and the phase setting until it sounds right to you.

I have tried subwoofers in the past but have always been disappointed.  I know subs have come a long way and would be interested in your thoughts especially people who have a similar system.

It's not really the sub as much as the room and the integration. The question isn't can you get a good sub, it's can yo make the room accepting of one.

Due to my  listening preferences I'm not a big subwoofer guy but they do add some heft and meat on the bones of your music. I don't have to have the lowest depths plumbed so I'm happy with a good eight inch that is both quick and articulate. 

I just ordered a SVS Micro 3000 sub. What sold me beside the good reviews is the ability to control the sub with a iPhone app. It also has an auto setup mode using a microphone. You have the ability to save different curves for different sets of speakers and because I'm old and screwed up, I don't have to kneel down or bend over to check settings. All controlled from my listening space. It's also not expensive at $899. 

It is best to use a crossover with low pass to the subwoofer and high pass to the mains. That means preamp/amp instead if integrated. Try just low pass to a subwoofer and complete signal to mains. If you cannot get a good integration then you know what is needed. Use two (or more) subwoofers, not one. I am using two JL Audio E112 (build-in crossover) with Quad ESL 63 mains, xover 80 Hz. In my room, 17’x35’ with high ceiling, I have bass flat to 28 Hz and no significant bass boost (at main listening position) in my setup with REW and a UMIK-2 microphone.

Which subwoofers disappointed you and where / how did you position them?

Have you considered B&W's own DB1 or DB2? 

Bob, unless you go to the extreme of buying a digital preamp with bass management and room control bypassing the low pass filter in the subwoofers, and get two very high quality subs you are always likely to be disappointed if you are critical with your bass. But, done right it would add greatly to your system increasing head room, lowering distortion and extending the bass down below 20 Hz. People will say the it is unnecessary to go below 20 Hz because you can not hear it. This is dead wrong. You can't hear it but you sure can feel it. Big venues breath at very low frequencies and with digital playback you can feel this in good live recordings. One problem with vinyl is that the very low bass is confused by record irregularities and to prevent your woofers from flying across the room you have to use a high pass filter below 20 Hz. 

+4 For two subwoofers.

Thank you to everyone who has replied.  I apologize for not responding sooner.  I am still digesting all the responses.  It feels like the solution maybe  more complicated than I anticipated.  

To: m-db

Sorry man, I do not recall what subwoofer was tested.  I do remember that it had an integral power amp .  It probably was at least 10 years ago so the details are a bit fuzzy.  I do remember it being really sloppy.  It was loaned to me from my local Audio shop (Listenup) for an at home audition.  That shop has always carried decent audio equipment.  I'm not blaming the shop or the equipment. I'm pretty sure I did not set it up properly.

Forum and responders, Thank you again.  This place is awesome wealth of information.

I have much studying and work to do on this subject.

Cheers!

Bob-

Foolish to even have a sub  if you do critical listening !

If you are a rocker makes zero what you do.

Kind of interesting how this thread has examples of the best and worst experiences with subs.

I believe all of them, and it is that variety of experiences with subs that I find curious and try to talk about.

@delm, Said:

It is best to use a crossover with low pass to the subwoofer and high pass to the mains. 

       I agree!

+1 Mr. Squires.

Bob, if you are overwhelmed by all the varied responses of models, brands and settings don't despair. Until you have heard your system with a properly set up subwoofer/s you may decide against even using them.   

Even though a subwoofer system takes the music signal and the volume setting from your H390, subwoofer/s are located and tuned independently of the main system. 

Powered subwoofers can have as few as three adjustments as well as a seemingly limitless amount of both internal and external processor control, memory presets and monitoring. Low frequency can be as simple as set-it and forget-it to affordable remotely controlled interactive excitement. 

You seem to have a good relationship with your local dealer. It may be worthwhile to have the dealer do the subwoofer setup process unique to your system and your room as a starting point. Have fun.

Hi guys, thanks again for the help and advise.  So I’m doing some YouTube homework and I find this.

Holy crap!  I need to get out more!

Cheers!

Bob-

Bob, your new system is probably fabulous sounding as is.

I'd go another way and tell you to drop $2400 on four SVS older SB-2000 self-powered sealed subs and do a distributed bass array for low even smooth bass when dialed it. It'll be a whole new world down there.

I'd also recommend high passing the 805s if possible or they'll spend a lot of excess cone movement trying to put out the deep bass they don't need to.

Good luck however you go. I'd recommend a sub, or more, in general.

+1 musicaddict

Ok here is quick update on my progress.  I have done a fair  bit of homework.  Mostly reading this and other audio forums and watching lots of YouTube videos.  Yesterday I visited my local audio shop and listened to a Rel s/510 to try and get a sense of what  I might expect adding a subwoofer or 2 to my system.  This is the subwoofer that Rel recommends pairing with my equipment.  This sub was coupled with McIntosh MA12000 amplifier and a pair of B&W 802 D4.  The audio source was Tidal streaming thru a Node 2i.  We were using the MA12000's DAC.  I listened to a couple of tracks that I know very well and have to say I was not impressed.  The mid range was ok but the upper was not good and the lower end was down right crap.  We turned the Rel on and off and I was still not impressed.  I'm not sure if it was the speakers, the amp, the DAC or the sub.  But together it was not good and very difficult to evaluate what, how or if the sub was contributing.  I do recall listening to that specific McIntosh amp previously and was not impressed.  I did follow up with the rep who auditioned the equipment and he agreed with me that it was less than good. He also said that it was possible the subwoofer was not set up properly.🤣

In any event, I am still working on this and truly appreciate the forum input.

Best,

Bob-

Hi Bob,

Subs can make a substantial difference to most any system if they are set up correctly.  The addition of a high pass filter between the sub and your mains goes a long way in helping with that set-up. Unfortunately it does not appear that your Hegel is capable of integrating a high pass filter (i.e. crossover) into your system. I would look into subs that contain a high pass filter, such as the JL Audio “e” series or the Audiokinesis Swarm.

Talk with Duke at Audiokinesis to see if the Swarm will work with your system. Duke offers some of the best customer service in the industry and imo, the Swarm may be the best value available in subwoofer systems.

Also, read this.

https://www.soundoctor.com/whitepapers/subs.htm

(Full disclosure; I do not own a Swarm system)

Yes, a pair of subs will help your system immensely. 

Not only will they fill in the lower octaves of music you are missing, that provide a lot  of visceral impact. But there is a lot of ambient information carried in very low frequencies, so imaging and soundstage will improve, too. 

+1 @simonmoon 

+2 @musicaddict 

The most important part of extracting great performance with subwoofer(s) has been touched on by a couple of others. It is not only proper integration with your main speakers, but more importantly, with your room. Getting bass "right" can be challenging due to how the room reacts when adding a subwoofer or subwoofers. Proper phase setup along with physical location in the room relative to your mains and listening position is critical. Getting that proper integration can take days or even longer with experimentation of not only the settings on the subwoofer, but also its position within the room. Even moving the subwoofer a foot in one direction or another can have big impacts on peaks, nulls, "boominess" etc.

But with patience, it can lead to a whole new experience.

only a rocker needs loud noise, nobody else does not need a sub .

@jim5559 , Listening to 95% of the subwoofered systems out there I can understand how you would have that opinion. Most people only go 1/2 in when they get subwoofers. If you are critical it has to be an all or none proposition. To do this correctly you need at least two very sturdy subwoofers, digital bass management including selectable crossover points and slopes, phase and time alignment and room control, at least 1000 watts/subwoofer and decent room acoustics. If you could hear a system set up this way your opinion would change. Shoving one sub under a system with nothing but a low pass filter is a sure recipe for inferior sound. Doing it the same way with two subs is also a dismal approach. You are correct in stating there is a music preference for this kind of an approach. However, listening to a large symphony orchestra through a big system with SOTA sub bass is a thrilling experience.

I've had sub(s) for many years now and highly recommend them.

Having said that, sometimes I've found it really difficult to integrate them to the room.  I purchased a miniDSK UMIK-1 calibration microphone and the REW (Room EQ Wizard) software to help integrate the subs with the room and full-range speakers.

In our last house, my listening room had terrible bass acoustics, eventually I had to install 10 bass traps to tame the extraneous bass the room added to the music, and could have used more, but my wife was referring to that room as my "padded cell".

We moved to a new home and I had a customized listening room done as part of the build and I'm loving life in the new digs!  This room has some sloping intersections of the walls & ceilings (a good thing in my case).

I have a pair of JL Audio F113V2's (otherwise known as "overkill") and one of the sub's amps died, and while the amp was being repaired by JL Audio I was not a happy camper, as I not only missed the little bit of bass augmentation, I mainly missed the "visceral" experience that the subs add to the music.

@mijostyn +1. You nailed it, as did the @ejr1953  using calibration mic and software

I finally sold a 10+ YO pair of SVS powered subs; an Ultra and a Plus (the tall round cylinders). I was never able to get a seamless blend, mostly due to the volume control settings being too coarse, virtually impossible to dial in. In fairness they were not designed for quality 2 channel systems. May be better now, but...

One of the biggest issues I had was because polarity on many discs is out (especially with greatest hits, or multi- recording studios) compared to the rest of the frequencies, and while they have phase/polarity adjustment, it is manual. IMHO, having remote control over volume and polarity is essential to get seamless blending. IMO to achieve great sub bass, you need a separate beefy amp + active XO=$$$$+ SIGH

@tweak1 , I am a fan of passive subwoofers. Most of the amps included with subwoofers are of inferior quality and they interfere with the rigidity of the enclosure. All of the digital preamps that include bass management have separate level controls for all four channels and they all operate by remote. Mine is unique in that I can change crossover frequencies and slopes by remote, very useful.

I too am not a fan of built in woofers, or powered subs. I am currently using Emerald Physics 3.4s (open baffle), which have a 12" mid-bass with 1" concentric polyester tweeter. These would be sufficient in most rooms, but mine is ~35 x 21 with an 12’ open beam vaulted ceiling; front and rear walls are mostly glass. I am long awaiting Emerald Physics 2.8s (open baffle), same 12" mid-bass with 1" concentric polyester tweeter, plus a total of 4 @ 15" carbon fiber woofers. Should they ever arrive, they will present a new integration challenge. Im hoping the OB will mitigate the cabinet resonance issues inherent in most/all box speakers.