Sub Question. One higher quality sub or two lesser quality? (Rythmik vs HSU)

When I was looking into a second sub, REL themselves told me that getting identical subs was important. Others here have agreed and disagreed with that view. 

Via Audioholics: "Ideally you should use identical subwoofers for the best overall performance, but it is possible to mix and match subwoofer brands and types if you're willing to do the extra work. If using mismatched subs, bear in mind that systems with different low frequency cutoffs may well be in phase and additive over most of their band, but at or below system resonance may well be out of phase. This can put us in the position of having the sub with a higher cut-off frequency reducing overall system output below its cutoff frequency.   This is why we usually recommend using identical subs all around."

I asked Brian at Ryhthmik about the F12 and he didn’t think they have enough output to match the cornwalls in my room.

Oz

I’d start with a single sub assuming that the subs used if two are not as good or well matched to the system. Getting the right sub to match is paramount. Best to start with one. That’s all you need if listening from a single sweet spot. Then, if needed to balance out other parts of the room, add more later. I’d stick to a single sub model that matches well though different models might work as long as all match similarly well but I would get one right first then add more of same if needed.

One question I have is how are people connecting multiple subs to their two channel systems not necessarily designed to output to multiple subwoofers out of the box in a manner that maintains proper load?

@mapman asked: 

"One question I have is how are people connecting multiple subs to their two channel systems not necessarily designed to output to multiple subwoofers out of the box in a manner that maintains proper load?"  

I can't speak for others, but the Swarm and DEBRA systems use four passive subs which are normally driven by a single amplifier, and optionally by two amplifiers.   

The amplifier has line-level inputs, and if that won't do, then a voltage divider network can be built to derive a line-level signal from a speaker-level output, with the line-level signal then feeding the subwoofer amp.  

The amp we use is the Dayton Audio SA-1000. 

Duke

I would NOT add subs to those Cornwalls, with 15" woofers, ports, and high efficiency horns.

You could easily mess up what you have, it's very hard to add just the lowest ...... down to ....

You are looking at specs that say down to 34hz. that is in a test space, open air, your's are in a room, sound waves contained, reflected, your bass is maintained below 34 I suspect.

I strongly suggest you buy a decent sound meter, see what you are actually getting, and where. Look for any weak/too strong spots, standing or cancelling waves.

With that sound meter, if you add subs, (or change speaker placement) you will be able to measure/adjust the crossover/blend from your listening spot.

2 channel system: 1 pair of subs, directional, located next to the cornwalls, forward facing. Bass is stereo, and the overtones of all low frequencies also give directional cues.