I have questions about stereo subs and their placement, and would appreciate any comments or suggestions.
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I should mention that I have plans to treat my front wall with bass traps, and the 1st reflection points with acoustic panels.
I’m thinking of replacing my single Rythmik sub with stereo REL S/510’s. My current sub is normally placed near the left corner of the front wall, fairly close to the left speaker. I thought it’d be useful to do a sub crawl to test other locations: I placed the sub in my listening chair and played two tracks while listening at various positions in the room. The tracks I used were track 7 of The Audiophile Reference Disk Vol 1 (Room Bass Response), and Holly Cole’s recording of The Train Song. After this process I had two conclusions:
The sound in the front corner was the worst: obvious boundary interference resulting in boomy notes. I note that front corners are where that REL suggests for subs, and this puzzles me.
I listened in three other locations. The bass sounded better in these places (smoother, more balanced). None of these three was clearly better than the others.
It did not surprise me that my sub crawl demonstrated that placing a sub in a corner may not be the best choice (am I missing something here?). Even with room treatments, won’t this result in unnecessary boundary interference on the front wall? When I placed my sub elsewhere, the front wall had much less boundary interference — and there was less boundary interference in the room overall.
Since bass is non-directional, are stereo subs ever placed on the same side of the room? Or, somewhere towards the center of the room and and also to one side, or otherwise arranged asymmetrically? This seems counterintuitive to me, but I thought I’d ask.
FWIW, I have never preferred a single subwoofer placed in a corner. Always overpowered and over “drove” the space at any useful volume in my experience.
I have a pair of stereo subs in my office system (REL Tzero’s) and, like my single subwoofer placement (in my rooms), I have found that pulling them away from the side walls and out about 1/3 into the room provides a pretty even bass response.
Each room will be different depending on its dimensions and related acoustical properties, so you will have to experiment with a pair of subs just like you did with a single sub to find a good location.
Also, it has been my experience that properly integrated subwoofers are not necessarily non-directional. There is plenty of LF energy in frequencies that can be reproduced by good subwoofers that can prove to be directional, especially if set to run at a high enough gain. Since LF material may be present in both channels, my experience suggest that you will need some semblance of a left and right placement to get a smooth bass response with two subwoofers.
That is not to say they cannot be placed more toward the center of the room or otherwise pretty far apart from the main speaker locations in order to sound good.
I went from a single Hsu, near a corner of the room, to a pair of REL T/7xs, placed left and right, so they’re just outboard of the main speakers. It’s tamed some of the more severe room nodes I had with the single sub, but it didn’t eliminate them. I might be able to get more even distribution if I played around more with placement, but since it sounds great at my listening chair, and that’s the only place I listen from, I can’t work up the motivation to mess with it further.
Not trying to be noisy, but need more info to try and offer possible solutions:
What is your Rythmik sub’s LP (low pass) frequency and output level settings?
Are the SS3’s playing full range or HP (high pass) at a similar setting of the sub’s input frequency?
Are you driving the sub with a high level speaker input signal or a bass management low line level signal?
What is your room dimensions and front wall system arrangements?
I can only comment on what I’ve discovered so far in my journey. I’ve been moving from one rental house to another over the past decade, ultimately (hopefully) to finish up in my own place which I’ve designed with my own rig in mind. I have B&W 800 Diamond main speakers, augmented with a pair B&W DB1 subs. These are powered by Electrocompaniet AW600 monoblocks. I can’t afford and don’t wish to have a dedicated room for the system. I want to be able to enjoy the music not only when I sit and listen but also while I’m doing other things around the house.
What I’ve learnt so far is that, even with the best laid plans for an acoustically ‘good’ space (room) in which to play your system, you’ll most likely have room modes (peaks and troughs) at different locations and at different frequencies, particularly for low frequencies where the wavelengths are ‘of the order’ of the room dimensions. Since I’ve been in rental accommodation, I’ve chosen not to invest in room treatment that may not be ultimately used in my own place. Fortunately I’ve been able to get a satisfying sound from the 800s by careful set up. Predictably, the DB1s have been problematic. In one of Paul McGowan’s posts or videos he mentions the idea of near-field sub placement. I experimented with this with very satisfying results. I have the subs to the left and right and just behind my listening position. I was most surprised how well they integrated with the 800s. They aurally disappeared! If there is a time-alignment issue, I certainly can’t hear it but that may be because my 800s are located quasi-near-field (about 2m) from my listening position with zero toe in.
If your room allows it, I recommend you at least try it out. I think this near-field placement idea works because I guess it kind of ‘defeats’ the room mode issue (because your ears are so close to the speakers).