Your experience of moving to two subs

Thanks to everyone for their input! I have yet to play with my Rythmik and SVS together, but I'll report back when I do, since at least one person was interested in hearing about it.

I think it's unlikely I'll stick with a single sub forever. Conceptually, two just makes more sense, just based on the info provided in this discussion. 👍🏼

@gladmo Assuming your 7T's have a fairly flat frequency response down past 50Hz fugetaboud stereo.

The only time I didn't need to use the crawl test (you don't actually need to crawl but it won't hurt to do both walk and crawl) to map out my listening rooms bass mode / standing waves was when I used four subwoofers. Once you've mapped the room you'll know exactly, or at least near the optimal subwoofer/s locations.

There's a rub. Your going to need some long interconnects to do the crawl test and most likely a longer pair for the location. You don't need anything exotic. Blue Jeans Cable custom makes economical cables for this purpose.

Since both your subs come with a modicum of equalization you can adjust them individually to your taste then use the one with the remote control as the master to control the volume of both. You'll most likely run them together at a lower volume. They absolutly do not need to match. Good luck with the reward.  

One man's datapoint.

Hsu VTF2 Mark IV subwoofer. (Out of production.)

In TV system: one sub off to one side opposite main speakers but not in corner..

In audio system: four subs behind main speakers.

No difference between one sub and four. 

Subs make your main speakers sound better because they don't have to work as hard with the sub handling low bass duties.

This Hsu sub has two ports which I have plugged with the foam plugs that come with the sub. Less bass but tighter compared to leaving the ports open.

https://youtu.be/_7ZGLrOpCQo

https://youtu.be/xUMDlpVu98w

One sub is fine, two are always better. More is better in the case of subs. As others have said, multiples really can better fill out the sound stage and give a really full and balanced experience. One huge fallacy is that subs are for movies and not music. That is an opinion that is completely baseless, proven wrong consistently, and only held by insane "2-channel only" types and possibly deaf sheep herders.

What sounds good to me is what’s optimal in my system.

For me, the saying is,

What sounded good to me is what was optimal in my system, until I learned about how to improve it.

While I don’t want to be on an endless hamster wheel, this is a hobby for me precisely because I am striving to see if I can make things better.

I have been able to improve the sound in the past, and that motivates me to keep trying -- because it’s fun, not because I have a "grass is greener" dysfunction.

@dean_palmer said
“That is an opinion that is completely baseless, proven wrong consistently, and only held by insane "2-channel only" types and possibly deaf sheep herders.”

I say….

Thank you making me howl. That is so freakin’ funny!

I completely agree that by seamlessly integrating a sub or two (or four?) the listening experience can be taken to a level that is far more difficult to achieve relying on stereo “mains” alone. With subs added, it won’t be 2-channel anymore, by definition, but it will 110% still sound like it, meaning the sub(s) will not be discernible as a source of sound.

Coincidentally, my goal has always been for the main speakers to be undetectable also. Having 2, 3, 4 boxes in your room, but the illusion that the sound is not originating from them is central to the illusion for me. Speakerless-ness, I call it. If the illusion of speakerless sound is achieved, designations such as 2-channel, 2.1 or 2.2 are, for me, unimportant labels.

Of course the specific qualities of the “speakerless” sound (e.g, tone, dynamics, etc.) one pursues is a matter of personal taste and ever-evolving.

good rule of thumb on this subject

if you are listening to music (leave aside home theater movies booms and rumbles) and can hear and localize your subs, you are doing it wrong

the bass should just be in the room, coming at you like waves of energy

Update with a few notes on my short journey here:
(@soix, tagging u since u asked about my findings)

1) Reconfirmed more thoroughly my claim about aural locatability of my Rythmik F12G sub. Anyone can believe me or not, but when it’s only the sub playing music with a very low crossover setting, I can instantly locate where the sound is coming from in the room while facing any direction and standing almost anywhere in the listening room... except when I’m behind the vertical plane made by the sub’s cone. Then it’s a diff story and it’s not locatable. My ears have to be in front of the driver somewhere.
2) I had placed the single sub in the middle of my speakers because I needed the SPL from that single, relatively low output Rythmik, which is focused on speed, not loudness. So that position was necessary (you could say optimal... or not) because I really needed two of these subs to begin with in a room of this size, but only had one. AND, the extra low crossover point sounded the best in that position because of the directional effects I’m hearing with this single Rythmik sub, and how having it pointing right at the listening position affected the sound in the 40+ hz bass range.
3) Having the two subs in play (Rythmik F12G and SVS SB2000) far apart from each other totally alleviated both the directionality/locatability problem, and the issue with needing to use an unusually low crossover point.
4) The Rythmik is a totally different animal. I listened to both of them with speakers off while doing test tones for phase adjustment and with music. There’s actually music and details coming through the Rythmik, both in the lowest frequencies, and up through top of the audible range as it diminishes through the end of the crossover slope. The SVS is just blub, blub, blub, blub, and you really can’t make out musical details anywhere in its output. In comparison, it’s a bunch of noise and sounds really distorted. The Rythmik has so much more purity in its sound. I wasn’t able to get the SVS to blend in with my speakers, blubbing along like that. The Rythmik just disappears.
5) I bought another Rythmik. :)

Ther seems to be an assumption that bass is omni-directional.  It is not.  There is a point of origin for the original signal and two subs can resolve that reality.  It is like two ears helping locate the direction of a sound or two eyes resolving depth perception.  The only instance I can think of that might give false clues as to imaging is if the bass is recorded using a DI [direct in] input to the recording soundboard.  In that case, the bass is wherever the recording engineer decides he wants it to be.  "Prndlus" seems to be closest to this reality when he discusses soundscape and says, "And we want every directional cue we can get for the best soundscape ".    I agree !

I've got two subs run off miniDSP.  I think some kind of DSP is almost essential with subs. I am also running the subs left and right channels. At that point, the subs completely disappear. What I really hate is being able to locate the subs in space. 

If I run the subs by themselves, they're really not loud. but if you run the mains without the subs it's very clear that the music is lacking.  That, to me, means something is right. 

It's worth doing some kind of room eq and dsp to tune in the subs, and while one sub is good two, run left and right channels is what works for us. 

Thanks so much for the update. As a fan of Rhythmik subs and an owner of an SB2000 (for home theater only) I especially appreciated your observations comparing the two subs — most enlightening! Glad to hear you found benefits in using two subs, and I’d love to hear your thoughts once you get the second Rhythmic set up and dialed in. I have no doubt it’s gonna be great and color me a little jealous, and there will be a pair of Rhythmik subs in my 2-channel rig as well at some point.

I had two SVS subs but was not happy with the quality of the bass for music. I moved to one F12 and I feel the quality is better. However, like the OP, I sense its location in the room and others can too, even though I left one of the SVS subs on the other side (my two svs subs were located R and L of the speakers) and only the F12 is hooked up. If I had only 1 sub it would have to go in the middle but with my set up it can’t. I don’t know how 1 sub in the center would sound having not done that but I think two would sound better at the R and L.  I will order another F12 in time.  

Question: Does the R and L channels get different bass in songs? Thus is there is right channel low freq signal that differs from the low freq left channel in music from my DAC which outputs as line level right channel and a line level left channel.

Thanks.

@soix I’ll let ya know.

@12many Yes, bass is mixed using L and R just like anything else. But the higher frequencies certainly give much more soundstage positioning cues. Often, the low bass sounds are set evenly between L and R, which is the same as center. Like, for electronic music’s synth bass lines. But recorded upright bass, or a large tympani could be set in the mix more to one side.

One thing that could lead to being able to locate subs could be that they're causing nearby objects to resonate at higher frequencies and you're hearing that.  I'd play around with tone generator a little to see if you can isolate anything.  

Long ago in my obsessive phase I made an extremely dead sounding room in my basement.  I made dozens of insulation bass traps, got equalizers and measurement mics and found out what accurate was, at least from a frequency response perspective.  One thing I realized is that if I clapped near one of my components it made a very audible resonance sound.  If something coming out of the speakers set that off it would have been a lot more added distortion than the component put out.  

@gladmo wrote:

Hi all, I have a 2.1 system with the sub sounding best in the center between the loudspeakers. My speakers have substantial, deep, and detailed bass for their size and with the SS amp I’ve chosen. Thus, the sub’s optimal crossover setting is only at about 28hz. I have plenty of bass amplitude going on -- don’t need "more" bass.

Rather than more bass it’s about added headroom via more bass capacity for a given SPL (i.e.: less excursion = lower distortion = cleaner, more effortless bass), as well as smoother frequency response from an addition of spread-out bass sources (the latter with a potential proviso, to my ears, certainly with 3 or more sources asymmetrically placed).

You always dial in the sub section for overall balance, irrespective of capacity, but when given more headroom and a smoother FR the perceived bass quality takes a leap ahead. Which is to say: oftentime poorer bass reproduction is sought counter-acted with less gain to "hide" a more obvious character of bass, but at the expense of proper, clean bass balance and fullness. So, in effect a cleaner bass can/should be dialed hotter.

I’ve taken advantage of the design of my pair of tapped horn subs, symmetrically flanking/positioned behind my mains, both with regard to smoother FR and even higher sensitivity in a single move - literally: by more effectively using boundary gain as a means of extending/enlarging the horn by firing into the concrete side walls (instead of straight ahead) at a fitting, calculated/simulated distance. That translates into a sensitivity of 108-110dB’s/1W/1M from 25Hz to >100Hz and a more even FR - win-win.

Many already lower sensitivity and direct radiating subs are only operating in a 1/2 space environment (vs. a 1/8 space ditto mentioned above from a sub principle easily 10dB’s more sensitive in itself), meaning they’ll have to work much harder for a given SPL. This is not without sonic implications, I might add, but few really consider the importance of headroom.

I’m wondering about soundstage effects of having two subs on the outsides of my speakers, though. Having my sub in the center does result in some apparent compression of the low frequencies towards the low-center area. The L and R channels from my preamp are combined at my sub. I know some people may disagree and think that the source of frequencies below 60hz can’t be located by human hearing, but my experience tells me differently.

I absolutely agree with you on this, and this is why I find a pair (and no more, unless placed on top of each other for towers) of symmetrical-to-the-mains placed subs to be paramount. It’s also one of the reasons why I’ve never fully warmed to a DBA sub setup, not least when asymmetrically placed throughout the listening space.

Does anyone have an opinion on the benefits of 2 subs vs only 1 when there’s no need for more bass oompf?

Again, it’s not (as much) about "oompf" than it is a cleaner and smoother bass response with more headroom, but to my mind the addition of radiation area only adds to the realism of sound with better physicality; you can’t really overdo capacity, it’s with you do with it and the advantages it can provide you.