Rivendell61 Posted March 24, 2005 Share Posted March 24, 2005 I am looking to combine two speakers in a way which will effectivly mimic--in a room--a single speaker mono system. Two Heresys (Heresies?) stacked..... Two Fortes side by side.... Now I know there will be some interaction between these speakers-- But is there anything happening which--in the real world--would create an audible problem? Are there any 'rules' for this sort of construction? Like...placing drivers certain distances apart to minimize problems? Inverting one speaker.....? Any help will be much appreciated!! Mark (By way of explanation.... I am trying to put together a true mono--single speaker--system. Mainly for playback of mono CDs. There are 'issues' with all the possible ways to sum/fold the two CD channels. Electronically summing via Y cords/mono switches.... I am considering as perhaps the least-likely-to-screw-things-up alternative to be simply acoustically summing--with what effectivly would be a large single speaker) Quote Link to comment Share on other sites More sharing options...
tonygeno Posted March 24, 2005 Share Posted March 24, 2005 If you stack two Heresys, they will work best stacked top to top. Quote Link to comment Share on other sites More sharing options...
joessportster Posted March 24, 2005 Share Posted March 24, 2005 i have cornwalls stacked atop my la scalas, and the sound is simply awsome, i also have heresys stacked atop my second pair of cornwalls, and they sound great also, have had no problems at all, the sound gets much larger IMO Joe Quote Link to comment Share on other sites More sharing options...
Rivendell61 Posted March 24, 2005 Author Share Posted March 24, 2005 Thanks guys-- Tony says: "they will work best stacked top to top" That would place the tweeters in the center of the stack....woofers top and bottom. Now why is that? I'd like to understand what the theory is here.... Are we trying to get the tweeters closer...woofers farther...? My initial instinct is tweeter on top just for better dispersion. And to maximize separation of drivers. But I know nothing of the acoustic principles.... Mark Quote Link to comment Share on other sites More sharing options...
tonygeno Posted March 24, 2005 Share Posted March 24, 2005 They will sing as one if placed that way, tweeter to tweeter. There are many designs that use a similar layout. Quote Link to comment Share on other sites More sharing options...
WMcD Posted March 24, 2005 Share Posted March 24, 2005 It seems to me that the tweeter to tweeter set up is very much like a D'Appolito - MTM array. You'd have to find more on the Internet and why it is good. Some of that is crossover effects and phase. I think that is only part of it though. The typical MTM set-up has only three drivers in the totem pole stack. It is probably equally applicable to a six driver (three pair) totem pole. (No offense intended to those whose cultures make totem poles.) In any event, you can see what happens with relative spacing of the members of the pairs of drivers if you imagine spacing in terms of wavelenghts in which they operate, say the middle of their operating band. This wavelength thing is very, very important in conceptualizing any wave mechanics problem. You have to recalibrate thinking to wavelenghts and not absolute distance. Without doing the math . . . the tweeters are spaced about 1 or 2 wavelenghts apart; the mids are spaced about 1 or 2 wavelengths apart, and the woofers are spaced about 1 or 2 wavelenghts apart. This is because the wavelenghts in which they operate vary the same as their spacing. This is true even though measured physical distance between the pairs of drivers is increasing as we move from tweeter to mid to woofer. Therefore, the inversion of the top unit actually creates a great deal of symetry in spacing of the individual members of the pairs, as compaired to the others. Gil Quote Link to comment Share on other sites More sharing options...
Rivendell61 Posted March 24, 2005 Author Share Posted March 24, 2005 Thanks Tony and Gil, I've seen speakers with the vertically symetric drivers (I think some JMLabs too?)--I can see how it makes sense. But then again I've seen speakers in just about every configuration (I have some Allisons with top firing woofers....). I'm never sure what is fashion and what is valid function. At least no one thinks the stacking (or Fortes side by side) proximity is a priori a bad idea--with too much cancellation, reinforcement, etc. Thanks, Mark Quote Link to comment Share on other sites More sharing options...
michael hurd Posted March 25, 2005 Share Posted March 25, 2005 Placing two speakers side by side, will result in lobing - sound hotspots as well as nulls. Inverted stacking with the tweeter to tweeter is the best way to acomplish what you are looking for. Quote Link to comment Share on other sites More sharing options...
Rivendell61 Posted March 25, 2005 Author Share Posted March 25, 2005 Oh boy! Stacking those Fortes should be interesting.... (I did find some other interesting info tonight including an early Absolute Sound article by Harry Pearson advocating stacking Advents, double and even triple stacked!) Thanks Michael, Mark Quote Link to comment Share on other sites More sharing options...
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