What's baffel step effect?
You know how they ( home theatre salesmen/installers/manufacturers etc.) tell you that bass is non-directional (so having a single sub anywhere in the room in a stereo/surround system will work just fine)? ... but then they never tell you at what point exactly this happens.
The reason is that it is not a fixed universal frequency at which bass becomes non-directional. It is determined by the the size of the speaker baffle - the point where the shortest dimension (i.e. either the width or height of the speaker) = 1/8 of the frequency. At this point the sound waves wrap around the back of the speaker and radiate in all directions vs just forwards at the listener resulting in a -6db shelf (in terms of output; SPL) from that point down (and a -6db per octave slope down to that point). Putting a speaker right up against a wall (or soffit mounting it in a wall) reduces/eliminates this effect because the soundwaves can't go backwards (or not very far before they bounce back). Some speaker systems (notably pro studio monitors and hi end hifi) have circuits or other mechanisms (such as a duplicate woofer on the rear crossed over around the transition point) to compensate for this. This is another reason (aside from the oft-cited "larger cones move more air" thing) that smaller woofers tend not to produce as much bass (smaller woofer goes in a smaller box, with a higher transition point).
Anyway, the things to take away from this bit of info are:
- if your amp/speakers are too boomy, move them away from the wall *
- if your amp/speakers aren't bassy enough, put them up against a wall ... if already up against a wall try a corner *
- never buy a hifi/theatre system that has really really tiny main (L + R) speakers (we've all seen those little cubes, or superthin
towers poles) + sub and expect a nice smooth integration between them (unless you litterally put the mains right up on/in the wall). You likely will not be able to adjust the crossover point high enough, and if you did, the top end of the sub's response would be directional and make things weirder.
* Some amp/speakers (mostly studio monitors, as far as I have seen) have a room mode selection switch - you can use this instead (and not just as intended, if a weak bass speaker you may opt to have it up on a wall and set it for middle of the room mode for more bass). Labelling on the switch varies from the simple English "corner", "wall", "in room" (or similar) to the a more technical description of the dispersion pattern based on speaker placement: 2pi (forward only, i.e. up against or in a wall), 4pi (away from walls or other boundries), pi (corner), pi/2 or 1/2 pi (tri corner, like where the corner meets a floor or ceiling) or sometimes a middle of the road sort of thing (just to confuse people) of "full space" or 1 (out in room), 1/2 space (wall) , 1/4 space (corner) and 1/8 space (tri corner). Not all implementations have all 4 options.
Way back around 1982 when I had a TNT-130 with a single 15", I remember that you had to pay extra to get a "Black Widow equipped" amp. I did not pay extra. Was mine a Scorpion? Or were there other driver models?
They had other models that they used as well. Dunno what you had, but not all the speakers Peavey used had Metal names like these 2. I'm not sure whether all the speakers they used were branded Peavey or not, but another example of a Peavey-branded speaker is the Sheffield line.