Subwoofer advice

@audiotroy  As posted above, I also have Harbeth m30.2s. 

I solved the Harbeth bass issue by adding dual HSU ULS15 mk-2s. (My listening room is (a) 12 x 14 for near field, which opens to (b) 20 x 30 which is why I upgraded the HSUs from VTF1 MK3s to the ULS 15s.

Also, having recently added the HSU High-End External Crossover I have a question:

I have been told that inserting a crossover between amp and pre will degrade the preamp output with noise, distortion, phase-shift, etc. when you go through the crossover electronics.  Also, that an external cross-over will also defeat any benefit of high-end after-market interconnects in the pre/x-over/amp path. 

Do you have any thoughts about this?
Thanks for any input.

(PS Audio BHK 300 monos, Audible Illusions L3A line stage, DSPeaker Anti-mode 8033, Modwright-modded Oppo Sonica DAC, Fidleizer Nimitra S server; cables - Syn Res; Wywires; Wireworld), 

Actually I sold the Harbeths.. sorry 😅

@d2girls Congrats on the 30.2s. I just upgraded from 30.1s recently to the .2s and love them. I had the same issues with Harbeth as you are having re bass.  My solution was as several have suggested here - adding sub(s). I started with one HSU VTF-1 MK2, then added a second. Each add was an improvement. I then upgraded to dual HSUs ULS-15 mk2s as the smaller sub was not adequate from my larger listening space. To my ears and taste the ULS-15/m30.2 combination equals virtually anything I have heard in a showroom (except the $175K Naim/Focal system at my local dealer's open-house last week.)

I then added an external HSU High-End Crossover unit. Despite what is IMHO a miserable build quality, the external crossover adds a bit of magic to the bass while allowing the Harbeth to shine where it does best - in mids an highs.

I do have a question about inserting an external crossover unit into a high end system which I will post in this thread. But in all, subs do the trick with the m.30.2s

Dave and Troy (audiotroy) just posted "the Rythmik (correct spelling ;-) subs I don't think can derive their signal from an amplifier." Look two posts above theirs, where I said Rythmiks do exactly that. The A370 (in the F12 sub) and H600 (in the F15HP and other models) plate amps have hookups for BOTH line level (from say a pre-amp) and high level (from a power amp) sources---your choice which to use. Dave and Troy---got it now? ;-)

Thanks all for the help, I am looking to get a full range speaker to replace the harbeths with. Seems like the better, simpler solution than trying to round it out with subs. Honestly, I didn’t even want to change anything, its my significant other who seems really keen on it.

I was seduced by Harbeth marketing! I shoulda gotten something different, something better. Shoulda Woulda Coulda. You guys know I haven’t even been in this hobby for longer than a year right? Plus I’m 1/3 of your guys age. I’ve got plenty of time to learn more. Let this be a lesson learned... at least I didn't blow $30k on a single component like some of you guys... also I'll be able to sell the Harbeths for pretty much 90% what I bought em for. Got lucky there, I guess.

And all this said and I haven’t even really said anything about how I like how my Harbeths sound. I love them to bits. Obviously when you read a thread like this it seems I’m not 100% pleased with the bass output in my system. But I’m mostly pleased. As I said before, I'm not the only person who has a say in my system. It’s as simple as that. If it were up to me I’d stick with things as is, maybe add a sub.

And yeah I guess thanks Audiotroy for your suggestions and pointing out that I bought a speaker that doesn’t do bass. I actually knew that buying them. Blame the boyfriend for putting thoughts of upgrading into my head...

This thread has served its purpose. See: the new thread I’ve made, titled Deadalus Audio speakers Muse or Muse studio?

D2girls, you purchased a speaker that has limited bass, which will not really do that kind of music well, and due to its light weight cabinet it tends to be more warm and melodic then tight and punchy in the bass, which also makes intergration with a subwoofer more difficult. 

Harbeths are very musical midrange oriented loudspeakers like we have said in many a post. Shadorne is correct. 

Also a 10 by 14 room is really too small to really get two subwoofers in.

However, the correct way would be using two small very fast subwoofers, to provide a more even wave launch into the room and smooth out nulls, SVS woofers are a bit too boomy, and the Rethmik subs I dont think can derive their signal from an amplifer. 

Two Rel subs should do the trick. Put some Isoacoustics isolation footers under the Harbeths. Try to find a Rel dealer and borrow two of their smaller subs. You do not need a lot of output your room is tiny. 

If you try to roll off the bass to the Harbeths and put an electronic crossover in line with the speaker you may lose much of the musicality that you love out of the Harbeths. 

If you just augment the bass you may find that the extra output from the subs coupled with the Harbeths will just add that little extra you are looking for. 

Dave and Troy
Audio Doctor NJ

Def 2 subs.  Everyone says this.  Can't go wrong with Rythmik or Power Sound Audio (PSA)  or SVS.  Folks who own the sealed SVS SB-2000s 12" give them lots of praise.  They are $1300 for 2, five year warranty.  The Rythmik F12 is a 12" sealed servo-controlled sub (the boss has a Ph.D. in EE), in a larger enclosure, and digs deeper.  More expensive, but, yeah, digs deeper.  About $1800 for a pair.  PSA is more of a home theater sub maker, but they do make sealed subs.  SVS has the best trade up policy, but they all have their own.  Bottom line, you can't go wrong with any of the 3 companies, but get 2 subs.

@furiouslyadrift is very right about the Rythmik subs. Their plate amps have far more controls for achieving integration with main speaker than do most others. Not just the adjustable crossover (frequency and slope), but continuously-variable phase (not the insufficient 0/180 degree toggle switch found on many), damping (high / low / medium, at 14 / 20 / 28Hz), both line (from pre-amp) and high-level (from power amp) inputs, and 1-band PEQ.

You can’t fix Harbeth bass with a subwoofer. It has a highish Q with resonance around 100 Hz from the woofer/cabinet and further port resonance at 50 Hz. This adds a permanent warmth to the bass much like a tube preamp. You really can’t get rid of it as it is a fundamental aspect of the design.

The bass will never be tight like you would hear on a low Q sealed box speaker playing Billie Jean.

I strongly suspect this is your problem- you have discovered a little weakness in the design (which is a strength viewed from another perspective). That said, the speaker is superb for jazz trio, pop and classic rock and any laid back female vocal piano stuff. Just don’t expect thumping disco or funk band or full orchestra to come out superbly articulate in the bass.

The best you could probably do is to gently roll off at around 110 Hz with a filter and hand over to a sealed JL style subwoofer at 90 Hz - this should give you an improvement in articulation.

+1 for upgrading the speakers. That is the path to better sound quality without the complications of integrating subwoofers that will be slightly out of phase with your main speakers, despite all efforts. 

My SO wants us to just get better speakers... anybody know anything about Daedalus audio? Specifically the Muse

I agree with Steve. Go, with SVS and set the SVS to slightly overlap with the bottom active of your main speakers. I use two SVS, one on each channel and and have experimented with their digital interface to achieve
excellent results with my full range B and W speakers. When set properly,
two subs will significantly improve your sound stage.

I have 2 REL T7i subs in a similar sized room and they made a huge difference in my SQ. 

Rythmik's are extremely easy to integrate into the room. One sub in between your mains is easiest as you will (probably) have the least issues with phase and timing. Two is generally diagonal in the room.

Integrating more than one sub is really hard without some sort of room correction, though.

Go with SVS and save some bux.

What about replacing your speakers with Harbeth 40.1 or 40.2 instead of adding subs ? Too expensive ?
Not that I am against subs, I just view them as a last resort solution.
Yes, I would start with one REL, though two identical RELs should be better even in smaller rooms.

if I were to get two subs, what would be the bare minimum to integrate them into my system? hook up the subs to the outputs of my pass labs preamp? i think i understand that if i did that, my speakers would still be going 'full range' and i would adjust the subwoofer crossover manually. right?
what would be the next step above that?

 I am not saying  Mr. decibel is wrong, you may find that you notice the woofers on the Harpeth struggling. But I would doubt it given the size of your room.   If you do you can just add a simple capacitor in line to your main speakers to accomplish and earlier rolloff  

I run my mains full range and only run across over to my subs to fill in the bottom. I don't notice the mains struggling at all, they just naturally roll off below 50 as they normally would.
 Given the OP has such a small room I would suggest to start with one and just run it off the second pair of outputs on your preamp.   Go with Vander Steen or REL. 

d2girls, I hope you allow my opinion. If adding a subwoofer or 2 to your system, it will definitely extend the last octave to your systems presentation, but, unless you cross over the main amp ( Pass 30.5 / Harbeths ) from running full range, and keep the higher spls the same when listening to Daft Punk, you will still hear the struggles of the Harbeth woofers you speak of. Hopefully, others will jump in with their experience and expertise. This has been my experience. Enjoy ! MrD.

Aside from the rapidly falling price of subwoofer room correction what is your issue with the likelihood of improved system and room integration over simple crossover and two position phase adjustments?

With integration factors as varied as the rooms and systems, you might opt for a manufacture that offers a convenient return policy. While your level of success maybe entirely subjective my experience with room correction with some level of manual adjustment has always yielded quicker and better integration as well as any other perks that a particular processor might offer.

Depending on the room the 30.2 appears to begin rolling off at 60Hz and down 4-5dB at 45Hz. I don't think one need to be a "bass head" to appreciate the potential overall improvement that most users gain with the addition of a more seamlessly integrated subwoofer/s.