REL Classic 98

@gdaddy1  Two stacks needed, or does one suffice?

@hickamore  Since its non-directional one stack works just fine. I took RELs advice and started in a corner location. I ended up about 30" out from the corner along a side wall. Bass sounds like it's coming out of the middle of the sound stage image.

It's important to note that in order for this to work properly both subs should be the same make and model. Prefer high level inputs for dynamics and easy linking them together. For music I much prefer a sealed box. They should be stacked as close together as possible. With feet removed and a thin layer of drawer  liner so they don't move. The concept is to 'couple' them together as one unit. Takes two single subs and turns them into one super sub.

Again, this is NOT about making them louder. There's a misconception that it will be so loud it will over power the room. Your comfortable bass level is what you set it at. This is about effieciency through physics and taking the stress off the speaker.

When my subs were set in stereo the gain control knob was set at around 1:00 once they were stacked  the boost in gain of 6db required the knob be turned DOWN to around 10;00. I couldn't believe it!

Low level listening is also improved. When the music is turned down there's still a pleasing 'thump' to the music.

The movement of the cone will be LESS. The voice coil will operate closer to it's center point where it's most effiecent with less distortion. (the longer the throw the more distortion.) The bass will be more effortless, cleaner and well defined because it's not working as hard. Same goes for the amp. The availablity to now adjust the crossover differently on each sub improved the entire bass spectrum.

It took a total of a half hour to stack them as an experiment and cost nothing. If you don't like it just put them back. This simple experiment yielded the biggest improvement in sound I've ever done.

Thanks!

I have a single Classic 98 I would be happy to part with, as I’d really rather have a 99…which was announced the day after my 98 arrived!  I have no complaints with it but bigger is better and I have room. My sub is in pristine condition with original box & packing. I will list it on USAM. 

Despite the opinions here, there are no rules when it comes to speakers, and subs are speakers. Speakers are always room dependent. One sub or two, stacked or separate: it’s all room dependent. Years ago a friend bought two REL Gibraltar G1 subs and REL sent a technician to install them in a large irregular space. I was there as he moved a single sub around the room using a test disc. He found two spots that worked well, one better than the other. He stacked them in the first spot, then put them in two different spots and the latter worked better. Then he adjusted the crossovers and level controls to make each integrate best with its main speakers. The controls were set differently from on another. He ended up with a near perfect balance despite the asymmetry of the placement. Why, because the ROOM!!! Room shape and size matter!