Stereo ... the ins and outs of a stereo cab.
will there also be a stereo Matrix 212 cab in the (near) future?
One of the things we get asked all the time is "Will you be doing a stereo version of xxx". It may sound a simple question, and it may even appear there is a simple answer, but from where we sit there are some issues with producing a stereo cab. I thought I would share with you some of our reasoning and company ethos on this.
Lets first talk about stereo itself as a concept. We've all sat at home with a hi-fi, two speakers arranged 15 feet apart, and a comfy chair in the center, making something akin to an equilateral triangle. The basic stereo concept is that for optimum stereo effect, you need to be about as far away from the speakers as the speaker are apart. You may have stereo speakers on each side of the computer monitor, and you sit around 18" away. However it is arranged, the basic triangle is maintained and you get a pleasing stereo effect.
As you have probably noticed, if you move the speakers closer together, narrowing the triangle, the stereo effect is reduced. If you take this concept into the guitar world and a typical 2x12" cabinet, assuming it was stereo, then the optimum listening distance would be around 18" away. Certainly, 30 feet away in the audience, any stereo effect would be negligble. In our humble opinion, if you want true stereo, the best solution is to buy two cabs, put one on each side of the stage and give your audince at least a fighting chance of hearing the effect.
OK, so maybe you say "OK, yeah, I get that, but I'd still like the sort of 'pseudo-stereo' option, it gives the sound a lot more space and air". That may be true close up on stage. But heres the thing; on an FRFR cabinet, that would involve providing two bass and two HF units. If you look at the stereo content of a typical guitar signal, most of it is in the upper registers, in other words its the HF unit that will be carrying a lot of the stereo information. If we provide 2 HF units, one each side of the cab, firstly the audience wont really get much in the way of stereo effect. Both signals will arrive in both ears, with equal loudness, similar timing.
What you will get is massive phasing issues, particularly when the cab is used in mono. Given that not all patches have stereo content, even if wired up in stereo, you would end up actually playing mono for a lot of the time. You now have two HF units producing the same signal, your entire audience is now hearing your sound from two, closely spaced sources. Depending on where they are standing, they will hear peaks and dips as the sound arriving at the ear either cancels or re-inforces the sound form the other driver. With peaks and dips at regular intervals up and down the HF spectra similar to the teeth on a comb, this is referred to as "comb filtering". Forget +-3db flatness on the signal, +-20db peaks and troughs are the order of the day. Dispersion figures become meaningless as the constructive and destructive interference creates dead spots all over the soundscape.
Theres no magic that will solve that. No DSP or amusing arrangement of drivers can get around the phyiscs of the matter.
One option would be to build a unit with THREE HF drivers, a pair at the sides for "pseudo stereo", and a centre one for mono mode. Thats not a route we have chosen to go just yet, and it would need an amount of DSP trickery to make it work properly.
To our minds, there is little point in providing the flatest possible response, the most carefully controlled dispersion and then pretty much destroying it by providing two HF drivers. The correct way to do stereo is to buy two cabs, and try and get some spacing between them on the stage. The more distance you can get, the better the effect will be to your audience. If you are restricted in space, use a mono FRFR cab and at least all you audience will get the same carefully crafted, evenly dispered, high quality sound.
It would be simplicity itself to make a "pseudo stereo" FRFR cab, but we'd feel like we were cheating you. Its not the right way to do it, we build our products with passion and integrity. No short cuts, no snake-oil. Its not that it can't physically be built, its simply that deep down, we know its not the right thing to do. Maybe one day we'll just call "uncle" and give in to the requests. For now we have enough on our plate delivering products like the FR212 which really do deliver an impressive and accurate response and let your audience really feel the energy and clarity.
I am sure there are other arguments, but thats our current thinking anyway, we hope it helps explain our position. Its not that we don't listen, its that we want to "do it right", even if that means turning away a little business in the process.