Sub to complement KEF LS50s: SVS vs. Rythmik

I am just going to chime in, please take my advice for what it is, some random guy on the internet:

1)  Noble 100 is absolutely right, the more subs, up to 4 (more than 4 provide marginal improvements), the better off you are in terms of smoothing out response and improving sound quality.  There is no amount of DSP that can make up for doing this acoustically.  

2)  Most room treatments provide minimal help for frequencies less than 100hz.  To effectively work, they must be large, and to remove large peaks must have a very narrow bandwidth (look up a Helmholtz Resonator).  GIK has excellent room treatments for reasonable prices and will, if you provide your room information, make suggestions.  

3)  This a controversial point, but in my experience high passing your main speakers makes a big difference, as it removes their trying to reproduce bass frequencies that increase distortion of the bass driver in your main speakers.  For some reason, people will argue against this, but I don't see them arguing you should remove the cross-over between your woofer and tweeter?!!!

In the case of your KEF's, that driver goes well into the midrange.  I also agree with Richard Vandersteen, that to fully integrate a subwoofer, your mains should have solid extension one octave below the cutoff frequency.  Your KEFs are close enough that using a high pass with them at 80 hz will work.  

4)  The vast majority of what we perceive as "slow" or "bloated" bass are room nodes and slow room decay.  Unless so poorly designed (generally a vented enclosure tuned to get maximum output) that transient response (really group delay) is so high it becomes audible.  Virtually no well designed home subwoofers suffer from this.  (As a note, most people perceive vented subs as tubby, because they have greater output: until recently, many, even high end, sealed subwoofers had a roll off starting in the 40hz range, now fixed by DSP).  

My two cents, get two or three less expensive subwoofers, carefully place them, and cross over your mains.  Rythmik offers the excellent L12 (white for $619 if you want that color) or LV12F, SVS the SB-1000 or PB-100, HSU the VTF-2 or ULS 15, or the RSL Speedwoofer 10s for $399, which gets you 3 for $1200.  

mcreyn, a random guy who seems to have considerable knowledge coupled with wisdom.

Hello mcreyn,

     I agree with almost everything you posted.  I mainly agree with your 3rd point but would just add that any achieved overall system performance gains, made from high passing your main speakers, are dependent on the degree to which your main amp(s) and main speakers benefit by being relieved of deep bass duties. The higher the main amp's power and the higher the bass extension limit of the main speakers, the smaller I believe the overall system sound quality performance gains will be.


Hello dancub,

     Adding a 2nd properly positioned and configured SVS SB-1000 sub to your system, in my opinion, would result in the bass being perceived as sounding roughly twice as good as a single sub even in your relatively small room.  You'll notice a general sense of ease to the bass, an increase in maximum bass output and an increase in the realism of bass dynamics due to the total bass duties being shared between two subs   
 neither of which is operating near its limits and both having ample reserve power for reproducing the powerful bass dynamics of music heard live at a small venue.  
     You'll also notice the psychoacoustic benefits to the sound that result from the use of multiple subs in any given room, that come into play beginning with two subs producing bass in a room and that are further enhance perceived bass quality in degrees up to a practical limit of four subs.  The clearly noticed progressive bass quality improvements noticed with multiple subs in any given room are an increase in perceived bass detail, speed, smoothness and improved blending or integration between the bass reproduced by the sub(s) and the midrange to treble reproduced by the main speakers.  The overall sound will sound progressively more cohesive as subs are increased from one to four in degrees.
     I know the SVS SB-1000 subs are small in size but very good performers that are a steal at the current price of $499 each.  My opinion is that buying and trying a 2nd one is a low risk and bargain price to experience bass response performance that I'm confident you will consider approaching state of the art even in a smaller room such as yours. Worst case is you try it out for 30 days, don't notice the improvements and return it for a full refund. Best case is you try it out, discover you suddenly have exceptionally good bass response in your room/system and begin thinking of the further gains possible by adding a 3rd or the ultimate fourth sub.  Other important qualities of your sub is that it's relatively small, has all the important configuration controls and overall is an ideal sub to be used in multiple sub systems.
     I should also mention it's very important to precisely position and configure each sub once you enter the wonderful world of multiple subs. I have a lot of useful experience and knowledge positioning and configuring 1-4 sub bass systems gained through research and using them in my own system as well as setting the up for friends' and relatives' rooms/systems and I enjoy spreading the word on how well the concept works and assisting setting them up.
       Of course, the decision is yours but I'm also willing to help you out with the optimum positioning and configuration if you'd like (I'm retired and have the interest and time).  But I'm also sure SVS's call in support could also assist with this if you'd prefer.    
        

nobel100
Wow, thank you for the input. Your last point is one I've wondered about over the two years I've had the SVS...positioning. I recently read...who knows where...that in spite of traditional wisdom (i.e. you can't tell where those frequencies are coming from), that location can make a serious difference. What I remember is that they should be side ways from the primary speaker and behind. My current one meets the first but not the second criteria...if I'm remembering correctly....but bass integration in my room is pretty reasonable.  Actually, what I have been paying attention to most recently has been the lack of crispness or depth of voices (particularly female singers). This may be source material but the ones I love (Holly Cole, Siri Svale, Patricia Barber) have typically been well regarded productions. I'm going to take a rain check on your kind offer to help with the bass things until after I try out your recent suggestions (above) for bass management and play around with positioning to see if that helps with this "crisp" issue.  In between my own over abundance of retirement hobbies.  Cheers and thanks!

@mcreyn 
Point 3. Right?

@noble100 
Thanks for the help. My system currently costs less than a pair of KEF LS50s.

KEF Q150s - I paid $300
Monoprice Monolith Stands - I paid $75/pair
Peachtree Decco65 - $400 craiglist special
Google Chromecast Audio - $35
Sub - $20 craiglist special

I initially thought the sub would degrade from the definition in the Q150s, but it enhanced everything. Having some sub was better than having none. The casing of the sub says it is a Jensen JS1000-A. But looking at the driver underneath, I see the driver was swapped out for a Kenwood--possibly a car driver. Sorry for any heart palpitations this may have caused, but this is the reality of budget Fi. You'll be happy to know that I could hear the difference between Spotify and 16/44.1 once I placed the Q150s on stands. And know I can't go back! (Spotify and 16/44.1 sounded identical with the mains on a desk.)

I currently run speaker cable from the Decco65 to the speaker level input on the sub, then speaker cable to the Q150s. But I bet the Decco65 pre-out doubles as a sub out. Have to double check, though. Still, the Decco65 only puts out 65w, so allowing the sub to take over the probably helps free up power for the mains as you described, noble100. 

I have the crossover on the Jensen set to 50hz since that is the 3db falloff on the Q150. And I have the volume set appropriately on the sub to achieve a flat sound signature. 

The only way I would it would appear that I could daisy chain subs with the Jensen is through the speaker level input. 

As far as a sub upgrade, I have considered both the Rel 5Ti and SVS 1000. Rel seems to be of the high level input persuasion.