Constructie boxe, 2 difuzoare,1 tweeter

A652 The Signature Series by Vance Dickason
		Crossover parts
Inductors L1= 0.68mH, 0.17 Ohms, 14g air-core L2=0.47mH, 0.13 Ohms, 14g air-core L3=0.33mH, 0.10 Ohms, 14g air-core Capacitors C1=10.0uF, polypropylene C2=5.1uF, polypropylene C3=24.0uF, polypropylene Resistors R1=5 Ohms, 10 Watts R2=1 Ohms, 10 Watts
Dimension of box
Internal Dimensions=24.875"x7.5"x9" External Dimensions=26.375"x9"x10.75" Front Baffle=1" MDF Sides/Top/Bottom=0.75" MDF Brace All Members= 0.75"x 0.75" Construction=Butt Joint

A652 The A652 is a 2-way design using two Audax HM170C0 6.5" woofers and a TW025M0 1" soft dome tweeter, mounted in the popular D'Apollito configuration with the tweeter placed between the two woofers. Using this technique produces a smoother vertical frequency response above and below the listening axis. This enclosure is computer optimized for a modified vented QB3 type of response yielding an F3 of about 53Hz. This volume provides a well damped group delay profile for bass detail and produces an output of 105dB, remaining linear down to 37Hz. The advantage of using the double 6.5" woofers in a 2-way speaker is higher efficiency and lower distortion in the lower frequencies. CROSSOVER DETAILS The crossover is computer optimized (using LEAP 4.51) as a 4th order Linkwitz-Riley type at 2.8kHz which yields an overall efficiency of about 90dB. The crossover utilizes a modified 3rd order topography for the low-pass section which provides multiple break points in the transfer function at about 200Hz and 2.8kHz. This configuration produces an anechoically flat response up to the 2.8kHz crossover frequency followed by a between 3rd and 4th order acoustic slope at the crossover frequency (necessary to produce a flat summation with the drivers mounted in the same plane). The high pass section also requires a 3rd order topography to produce a 4th order acoustic slope, with the circuit resistance adjusted to produce as shallow a transfer function "knee" as possible. When both sections are acoustically summed together, the final response of the speaker is 60Hz - 20kHz +/- 2.2dB with a very flat off-axis response profile. SPEAKER LOCATION The A652 speaker is designed to be placed on a high quality well-damped speaker stand approximately 22" in height. This places the tweeter at 39" above the floor. As with any high quality 6.5" woofer, the low frequency response does not produce much output in the lowest octave between 20Hz - 40Hz. For this reason, this speaker makes and ideal satellite speaker to be used in conjunction with a powered subwoofer, of bi-amped with and electronic crossover, separate amplifier and subwoofer. CONSTRUCTION INSIGHTS The enclosure is damped internally using acoustic foam (ACl foam or equivalent) placed directly behind the upper woofer covering the top, back and side walls from the area above the internal brace (which is placed between the lower woofer and tweeter) to the top of the enclosure and directly behind the lower woofer covering the back and side walls from the area below the internal brace to about 1" above the port location. Additional damping material suck as Dacron or Acousta-Stuf is placed directly behind each woofer (use enough material so that it is held in place by the foam and does not fall downward and interfere with the operation of the port). The port tube should be constructed of 3" ID ABS plastic pipe. Vance Dickason