THE D'APPOLITO SPEAKER

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

This is a group of D'Appolito speakers. They can be used as bookshelves for the left and right main channels horizontally and for a center channel, vertically.

----------------------------------------------------------------

The top speaker to the left features a 5 way design which includes two midranges,two woofers and a tweeter. The company,Definitive Technology created a design I had conceived myself as a center channel.

-------------------------------------------------------------------------------------------------------------------------------

Recently, I made a discovery in a Optimus center channel

speaker in its wiring versus the Garrard units I possess and

some time ago possessing Koss M80 dynamite speakers. The Garrard used two 12 ohm speakers wired in PARALLEL giving an impedance of 6 ohms. The Koss had two 8 ohm speakers wired in PARALLEL giving 4 ohms. The Optimus and a Klh that I possess had two 4 ohm speakers wired in SERIES. My preliminary test of the Optimus and KLH seemed to throw a complete 5.1 speaker system into a MISPHASED circuit. I need to retest this speaker along with my others and switch the phase of the subwoofer to 180 degrees and see what happens.

-------------------------------------------------------------------------

Below is a piece of info from JIL subwoofers about subs being wired in series and the result from it. I am not quite sure what they mean other than this was the only piece of literature I could find on series wired speakers on the net.

-----------------------------------------------------------------------

IF I FIND AFTER THE TEST THAT I MENTIONED THAT

THE 5.1 SYSTEM REMAINS MISPHASED, I WILL WRITE A

NOTE ON ANY HOME THEATER FORUMS I BELONG TOO.

THE REASON WOULD BE THAT IF I AM CORRECT ON

WHAT I SAY, THEN IT IS POSSIBLE THAT MANY HOME THEATERS ARE NOT WORKING PROPERLY BECAUSE THEIR CENTER CHANNELS USE LOW IMPEDANCE WOOFERS WIRED IN SERIES INSTEAD OF HIGHER IMPEDANCE WOOFERS WIRED IN PARALLEL.

---------------------------------------------------------------------------

It is far less desirable to make subwoofer to subwoofer connections in series. Because of slight and unavoidable differences between speakers and because of the high likelihood of uneven loading between different speakers in a car, there will be slight differences in the mechanical behavior of the two speakers in series. These differences in movement result in induced voltage (called back EMF) being created by the speakers across the series connection. This effect causes a problem when two speakers which >behave differently are connected in series because the speakers can modulate each other (cause each other to move), resulting in distortion. The problem becomes more serious as more speakers are >connected in series. A good experiment to show the effect of back EMF is the following: >connect four speakers in series and short the positive and negative input leads of the series circuit. Push down on one cone with your >hand; you will notice that the three other speakers will move in the >opposite direction of the one you are pushing. Now, reconnect the >speakers in parallel, short the inputs and push down on one cone. The speakers will not modulate each other because each one is shorted directly.

SNELL CENTER CHANNEL SPEAKER

Expensive except for those who have the bread. What bothers me is the horizontal D'Appolito center of this speaker. I wish that part of the speaker was mounted vertically(W-M-T-M-W) Although I was never able to do a speaker experiment of the kind, it was my opinion that the ideal center channel speaker would be one like the Snell with a complete vertical mount. I have seen some main left and right horizontally standing speakers built that way(W-M-T-M-W) but personally I am not a lover of the D'Appolito design in any form as horizontal main speakers, but as a center channel vertical design, the D'Appolito is made to order in the handling of dialogue and center channel audio material. At this time however, I have only played with the W-T-W versions. However, it should be noted that there are two types of these speakers out there. One is a system with two woofers of either 16 or 12 ohms wired in parallel or two-4ohm speakers wired in series. Unfortunately, when you buy center channel speakers, you do not know what wired version you are getting. I have experimented with both forms and believe me, you want the former and not the latter.

A center channel tow in a unique design

When it comes to center channel speakers, some systems use a TOW(tweeter over woofer) set-up of a speaker that is the same as the satellites meaning their height is greater than their width.

In this case we have a TOW speaker center channel set-up where the width of the speaker is greater than the height so it is a vertical type system. The dialogue being reproduced by the speaker is reproduced over the width of this cabinet much like the tweeter-woofer-tweeter setup whose speaker cabinets are width greater than height.

The question to my mind is whether the above shown system can work as effectively or perhaps better than tweeter-woofer-tweeter systems. It might.