Just wanted to get some feedback regarding connecting two subwoofers to my integrated amplifier. The amp is a Musical Fidelity M6si and the subs are SVS SB 2000's. The Musical Fidelity has a single pre out. My question is whether there is any advantage to having both left and right channels going to each of the subs via dual Y-adaptors?I am not setting the subs up as distinct left and right subs, but will have one to the right of the front right speaker and the second sub will be diagonal from it in the back left corner of the room. Placement is as per SVS's advice, along with limited options in a small room.
No advantage. Doesn't matter. All the bass the subs get is mono anyway so it really does not matter if you split one channel to two subs, run one channel to each, or whatever. No difference. So use whatever is easiest/cheapest with whatever wire you have. (Subs are also remarkably unaffected by interconnect quality.)
Locating them asymmetrically like that is also the right approach. If you add more later that's exactly what you do, keep putting them along the walls different distances from the corners. I have five and more definitely is better.
Two subs typically perform and sound about twice as good as a single sub. You'll notice more solid and powerful bass with more realistic bass dynamics, a greater sense of ease, better detail and more seamless integration of the bass with your main speakers. Two subs have a basic advantage over just one primarily due to bass being cumulative in a given room; since there are two they can share the total bass demands between them with both operating optimally at outputs well within their limits. Here's the most useful advice I can give you for your scenario:
1. Most humans cannot localize (tell exactly where the sound is coming from) on bass sound tones below about 80 Hz, which means all bass below this threshold will most likely be perceived by yourself as mono. Since your integrated only has one set of l+r preouts and each of your subs requires a l+r channel input, however, I believe the connection method you described (using a couple of y-adapters) would work well. There's no real advantage or disadvantage of using this dual y-adapters method. You're going to perceive the bass below about 80 Hz as mono no matter how you connect your subs. The good news is that you'll still perceive a sense of stereo deep bass in your sound stage presentation due to the deep bass harmonics or overtones of the fundamental bass tones, which extend beyond 80 Hz and can be localized, being reproduced through your main stereo speakers.
2. If your goal is optimum bass performance at a designated listening seat in your room, I would also strongly advise against placing your subs in predetermined positions within the room, such as diagonally or any other convenient or predetermined locations. The reason is that bass sound waves have an omnidirectional radiation pattern and their lengths are so long ( a 20 Hz deep bass sound wave is about 56' long), it's unavoidable that bass standing waves will exist at specific spots in your room no matter where you position each of your subs. These spots are easily identified since the bass at your listening seat will sound overemphasized (a peak), underemphasized (a dip) or even non-existent (a cancellation) if your seat happens to be positioned by one of these bass standing waves. The only methods I'm aware of, to ensure bass standing waves don't exist at your listening seat, are to position each sub sequentially using the 'sub crawl' method (google it) or using mics and other room analysis and correction hardware/software. I think it's important to note that the above are not merely my opinions but are based on acoustic research and knowledge that can be readily verified online.
stereo subs are wonderful, transformative of many systems
good for you!"
Just for the record and your edification, there's no such thing as 'stereo bass' or 'stereo subs' beyond my description in my last post of the bass fundamental bass tones below about 80 Hz being reproduced by a pair of mono subs, which we cannot localize, and the bass harmonics or overtones of the fundamental bass tones, which often extend beyond about 80 Hz that we can localize,being reproduced by the main stereo speakers. Our brains are able to associate the bass harmonics or overtones, that are above 80 Hz and coming from the main stereo speakers, with the fundamental bass tones, that are below 80 Hz and coming from the subs, and create the perception of stereo bass. I suspect some individuals confuse these stereo bass perceptions created by our brain's amazing associative abilities with the results of simply physically configuring their system with separate l+r channel subs in their systems. They just don't completely understand the true cerebral associative forces at work and believe their "stereo sub" configuration is responsible for them perceiving stereo deep bass. In my opinion, this is a common and understandable mistake which, ultimately, is not that big a deal. No matter whether we configure our subs in stereo or mono operation, the final result is the same: we're all actually listening to mono deep bass from the subs and stereo harmonics from our main stereo speakers while our brains are doing the heavy lifting and creating the perception of stereo deep bass.
Tim is of course absolutely correct. This is something I was able to confirm by running my DBA both ways, stereo and mono. Makes no difference because even connected to L and R channels the signal is the same. Nevertheless, it sure does sound like stereo! It shows how very different we hear very low bass compared to 100Hz and up. When higher frequencies are played mono it all seems to come from right between the speakers. Mono recordings everything is in a sort of sphere dead center. But with bass its not like that at all. Low bass is mono and yet sounds stereo. The bass from a DBA is 3D and has location just as real as the rest of the stage. This can only be because somehow we integrate the higher with the lower frequencies into one holographic 3D soundscape. Really wish more people would do this, so more than a half a dozen like me and Tim would know what we're talking about.
I use MB Columns, 100-300 hz, VERY stereo.. 48-74" tall. Changes the whole way thing sound.. Took most of the little ripples out of the neighbors swimming pool. No kidding.. Wife’s not yelling turn down the music or BASS. I turned OFF two of my 300 lb bass bins, I use 1-3 smaller bass units, full DSP, depends on the music.
BUT I can get serious...Waves in the neighbors pool!!!
... there’s no such thing as ’stereo bass’ or ’stereo subs’ beyond my description in my last post of the bass fundamental bass tones below about 80 Hz being reproduced by a pair of mono subs, which we cannot localize, and the bass harmonics or overtones of the fundamental bass tones, which often extend beyond about 80 Hz that we can localize ... No matter whether we configure our subs in stereo or mono operation, the final result is the same: we’re all actually listening to mono deep bass from the subs ...
This canard has been around the audio world for generations, and it’s easy to see why. The fact is that it is extremely difficult to localize LF, and it’s much easier to integrate mono bass into a stereo system than stereo bass. As a result, monophonic subwoofer systems often sound better than many attempts to do stereo in the same system. (Indeed, when using mono bass, you can use multiple subwoofers - as @noble100 has touted many times - placed around the room where the effects of bass nodes can be best managed. That wouldn’t work with a stereo subwoofer system.)
But let’s be clear: Just because it’s difficult to localize monophonic bass, and just because installing satisfactory monophonic bass systems is easier and more practical than keeping the bass stereo, does not mean that all bass is mono. It isn’t, and the biggest clue that it isn’t is the audible result of phase differences in the stereo LF signal. (This is where stereo bass deniers often chime in with, "But all records and CDs are pressed with mono bass so it doesn’t make any difference!" And with those recordings, they’re correct.)
I’ve previously posted links to original research on this topic. In particular, studies done into lossy compression and hearing perception revealed this truth about stereo bass, as well as accepting that as a practical matter, it doesn’t really matter most of the time.
Wanna hear stereo bass? Get some good recordings with lotsa LF- it’s best if you use your own for reference - and listen to them on truly full-range speakers in a proper system. I’m talking about something such as the Infinity IRS Beta system, or Genesis Quartet. Then you’ll understand that stereo bass can be real, even if it’s elusive and, frankly, often of dubious practical appeal.
My introduction to stereo bass was by the late Mike Kay at Lyric using the big Infinity IRS V system. He loved demonstrating the reality of stereo LF.
@erikt No you aren't missing anything. Just semantics. When I said "single pre out" I meant a single left/right output.@noble100 Tim. My speakers are Vienna Acoustics Mozart Grand SE's and their rated response is 30Hz – 22kHz. The SVS sub low pass filter range is 50Hz - 160Hz. When setting the sub, do I set the filter at 50Hz or is it something done by listening?
Start low (50-80 max) and increase until it booms and back off a bit, (50-80). The "Gain’ at the 11-12 o clock position. Reading the book is alway a good idea. Less is better, not more, when it comes to bass.
Though 10-100 hz is NOT directional, 80-300 IS. There is a left and right channel of BASS. NO they are not recorded the same on the left and right channels, IT DOES make a difference whether you hook them up backwards, and or only use one channel. ALL the bass is not on one channel. You may have kettle drums on the left and a double bass on the right. Depends on the people that made the recording, I would separate the two.
tony1954: " @noble100 Tim. My speakers are Vienna Acoustics Mozart Grand SE's and their rated response is 30Hz – 22kHz. The SVS sub low pass filter range is 50Hz - 160Hz. When setting the sub, do I set the filter at 50Hz or is it something done by listening?
I think it's odd that the SB2000's low pass filter control only goes as deep as 50 Hz. Your subs have a rated bass output extension down to 19 Hz and I would expect the control to have a lower setting that's closer to that. Strange but we'll need to work with what you've got. I usually suggest to set the low pass filter about 5 Hz above the rated bass extension of the main speakers and then lower this setting as low as possible,in small increments, without noticing any negative impacts in the overall bass sound quality. For example, my main speakers have a rated bass extension of 35 Hz and I initially set the low pass filter at 40 Hz on my 4 subs. I auditioned the overall system sound quality at slightly lower, and even slightly higher, low pass filter frequency settings and determined that I perceived a setting of 38 Hz to be the optimum setting in my system and room. I also want to inform you that I run my main speakers full range and suggest you do the same. With your main speakers, my guideline would translate into setting the low pass filter on your pair of subs initially at 35 Hz and slowly lowering the setting from there until you notice a decrease in overall sound quality. Obviously, you can't do this since you're limited to a lowest setting of 50 Hz. The best solution I have thought of thus far for your situation is to try 2 alternative configurations and utilize the one that sounds best to you:
Option#1- Run your speakers full range and set the low pass filter controls on your subs to 50 Hz. Then initially set both subs' volume controls at 50%, or even higher, and slowly decrease both settings as low as possible, in small increments, until you perceive any negative impacts in the overall bass sound quality.
Run your speakers full range and set the low pass filter controls on your subs to the "LFE" position. This will effectively result in your subs operating full range, which means enough sound above 80 Hz may be reproduced by the subs for you to localize them. Then initially set both subs' volume controls at 50%, or even higher, and slowly decrease both settings as low as possible, in small increments, until you perceive any negative impacts in the overall bass sound quality.
My current belief is that Option#1 will sound better to you but I'm not certain. There is a 3rd solution option I've thought of but this would involve purchasing a Mini DSP unit, linked to below and not very expensive, that would be inserted between your integrated outputs and the subs' inputs.
Thanks for your input and suggestions. I believe option 1 will be the preferred option as well.So, if I am understanding option 1 correctly, I would run a cable from the left pre out to the "left" sub and then use a "Y adapter" to connect it to both the left and right line inputs. The right pre out would be connected the same way to the right sub.
Yes, you would need two y-adapters, one for the left channel and one for the right. You may also could check the SB 2000 manual and see if it's possible to connect the l+r channel pre-outs on the MF integrated to sub#1's l+r channel inputs and then piggy-back sub#2 to sub#1 via l+r channel outputs on sub#1 connected to the l+r channel inputs on sub#2. This would also result in both subs receiving identical signals just as dual y-adapters would. I'm just not sure if the SB2000s have this ability. I still believe that precise locating of each sub in your room, and in relation to your listening seat, are the primary factors in achieving optimum bass performance in your system. I used the 'sub crawl' method to sequentially locate the 4 subs in my room and it proved to be extremely effective.
@noble100 Tim. That would be my preference, but I was trying to avoid running dual cables between the two subs. I have talked to SVS, who were very helpful by the way, and I think I will be just running a single cable to the right/LFE line input on each sub for now and see how that works. If bass is non-directional and monaural below 50Hz, then the SQ will more dependent on the sub placement than the signal.
Yes, bass below about 80 Hz is non-directional and monaural. I think you're plan is good but I'm just concerned about whether or not frequencies above 80 Hz may also be sent to the subs and be reproduced.
I'm not certain but I believe the LFE inputs on the SVS subs have no filtering at all, which means your subs might reproduce frequencies above 80 Hz and you would be able to localize these as coming from the subs. If SVS can't clarify this issue, then you would likely need to try this setup to find out for yourself.
@noble100 Tim,As below, I have been assured that the low pass filter will always be functional regardless of which way I go."On our subwoofers, running the RCA into the LFE port doesn't disable the
ability to use the Low Pass Filtering Functionality. Actually running
to any of our subwoofer's ports doesn't disable the ability to use LPF. So,
feel free to just plug one RCA into the LFE port of each subwoofer and
back to the pre-outs of your integrated amplifier. Then just adjust the
That's okay but you still have the issue about whether 50 Hz is going to be the optimum crossover setting for your main speakers. I tend to think the optimum crossover freq would be closer to 40 Hz but you should check it out and make up your own mind. If 50 Hz is not low enough , I'd ask SVS why the heck did they make a sub with a rated bass extension down to 20 Hz and limit the crossover to 50 Hz. Then listen to their lame excuse and buy a Mini DSP to rectify their mistake and solve your issue.
Sounds good. I know from fairly extensive experience setting up my own and other systems with dual subs, that precise positioning of sub#1 and then sub#2 in relation to your designated listening seat are the key factors in achieving best results. I suggest taking your time to ensure accuracy and using the sub crawl method if you lack the more expensive room correction gear alternative. Assuming you don’t currently have the room correction gear, here’s the sub crawl procedure:
1. Hookup sub#1, place it directly in front of your designated listening seat and play some music with good and repetitive bass. Set the Volume level on each sub to 50%, the Phase to in-phase ("0") and the Crossover Frequency to 50 Hz. 2. Beginning at the right front corner of your room, slowly walk in a counter-clockwise direction around the perimeter of your room closely listening for an exact spot where the bass sounds best to you (powerful, solid, smooth, detailed, dynamic and natural). Remember to take your time, move slowly, listen closely and repeat from the beginning until you find the exact spot. 3. Once you’ve found the exact spot, move sub#1 to this specific spot. 4. Hookup sub#2, place it directly in front of your designated listening seat and play some music with good and repetitive bass again. 5. Beginning at sub#1, slowly continue walking in a counter-clockwise direction around the perimeter of your room closely listening for the next exact spot where the bass sounds best to you (powerful, solid, smooth, detailed, dynamic and natural). Remember to take your time, move slowly, listen closely and repeat this step from the beginning until you find the exact spot. 6. Once you’ve found the exact spot, move sub#2 to this specific spot. 7. Sit in your designated listening seat, play the music with good and repetitive bass again and verify the bass sounds very good to you overall.
If the bass does not sound very good to you, unfortunately, you’ll need to repeat the above complete procedure. If the bass does sound very good to you, the normal next steps are to optimally set, or fine tune, the Volume, Crossover Frequency (Low Pass Filter) and Phase controls on each sub. Since you’re going to set the Crossover Frequency at its lowest available 50 Hz setting, you’ll just need to optimally set the volume and phase controls.
Thanks Tim.I am busy for a few days, followed by a 4 day golf holiday at Predator Ridge in Vernon, BC, so the crawling will have to wait for now.It sounds good in theory, but in a 700 sq ft condo there is not a lot of actual spots to put two subs. Hopefully the stars will align and I don't end up with one sub in a door way and the other next to me on the couch.
Have fun and good luck. Remember, sometimes a little rearranging of your room’s decor is necessary for good home audio, just like a little covert rearranging of your ball’s decor/lie is sometimes necessary for good BC golf shots.
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