dbreggin

Can you help me ID this mystery (well, its a mystery to me) woofer? I thought I had Peavey Black Widows... 15" 5.2 Ohm DC resistance cast aluminum basket paper-like cone rubber guard around edge of magnet wire mesh screen inside magnet vent solderless quick connects imprinted with 7601001s or 76010019 Found inside a circa 1976 La Scala

DJK, WOW, and Thanks for the great info! Its a lot for me to digest at one quick sitting. [8-|] I do have a question about what you meant by this: Is this the XO spec for the low end? 35 to 400 Hz as follows: 400 Hz XO w/ 24 db/octave slope and 35 Hz Hi pass filter? Dan

John, Thank you for your response. Duly noted as things to look out for, and perhaps things to go and buy. In the mean time I have what I have (purchased as such at a really good price) and I am looking to make the most of it with what I already have. I may not have expressed myself clearly in my original post reagarding some points about what I am trying to do and my specific questions related to that. Tri-amping the system. From the top down it would look like this (XO in DBX DriveRack PA+): tweeter / squawker (200 Watts) Hi passed at 400 Hz 15' woofer (500 Watts) band passed between 125 and 400 Hz (this box not ported) 15" woofer (500 Watts) low passed at 125 hz (this box ported) Bi-amping the system. tweeter / squawker (200 Watts) shelved at 400 Hz 15" woofer (500 Watts) low passed at 400 Hz (this box maybe ported) 15" woofer (500 Watts) low passed at 400 Hz (this box ported) Note that the DBX DriveRack has a 28 band Real Time Analyzer and multiple eq's (28 band graphic and multiband parametric eq's) to start the fine tuning. it also has compressor / limiter functions, sub harmonic synth. I also will be using a Aphex 104 Aural Exciter in the chain just ahead of the DBX. The usual venue will be 300-500 seat theatres (high schools). The music will be live Bollywood dance music (think pop- top 40 instrumentation & vocals and effects), as well as some pre-recorded music for classical dance performances. Here are my most pressing questions: When I detach the 15" woofer from the crossover network, and change the injected signal from full range (to the hi pass 400Hz and up signal), is there anything I need to do to preserve the integrity of the passive crossover behavior for the squawker / tweeter pair still attached to it? How would anyone recommend the physical layout of stacked FH-1's if they are both ported. What else do you think I should know, or how else should I consider setting up the system?

DJK, Thanks for the feedback (pardon the pun). I know there is a boost in the lower frequencies (that's why I am looking to port), however a ported horn is less efficient overall than a true horn, to the point of some posters padding down their squawkers up to 6dB in reaction to thier porting activities. That is the loss I was referring to... and I think 2kw in the low end will allow me to make up the difference without padding down my squawkers. Are you able to run a sim with the Black Widow's spec to see how it might work?

My biggest question is whether or not I need to modify the type AA x-over when I detach the woofer from the network? If so, in what manner? Re-load the network with an 8 Ohm resistive sink? Should I just go for an aftermarket xover for just the mid-tweet network? Here is the proposed set-up: 2 stacks each with a La Scala full range cab plus an additional La Scala woofer cabinet. All 4 cabs are circa 1976. The tweeters are K-77s. Mids are original horns with new drivers: EV 1832 (2" voice coil, 110W continuous, 4 Ohm DC, 7 Ohm AC 800Hz- 1300Hz pink noise). Woofers are Peavey Black Widow 15", 8 Ohm, 400 Watt. specs below [8-|] Re is DC resistance of the voice coil in ohms Fs is free air resonance of the speaker cone assembly in Hz QTS is total quality factor in free air QMS is mechanical quality factory QES is electrical quality factor VAS is equivalent volume compliance of suspension in liters No is efficiency in percents VD is volume of air displaced in milliliters Xmax is T peak-to-peak maximum cone excursion in millimeters Model# Re Fs QTS QMS QES VAS No Xmax VD 1505-8DT 5.2 44.2 .37 7.8 .39 198 3.9% +/-4.8 385 Power is 2 ea. Crown XLS 802 (500 watts @ 8 Ohms direct to each woofer driver), Crown XLS 202 (200 watts per channel for mids and tweets through the type AA passive x-over). DBX DriveRack PA+ for the crossover My next questions are about the port-mod. Since I have more than enough power to withstand the reduction in efficiency [6], I'd like to port-mod (at least) the woofer only cabs. Based on the driver I am using, is there a different CU IN volume to be used, or just build as designed? I ask this because of the large volume displaced by the driver, and I remember this being mentioned in a thread as one of the variables in the calculations. How about tuning the ports? Anything different here? If I also port-mod the full-range cabinets, How should I deal with the 2 ported cabs in one stack? Ports in the middle, ports below each woofer? Another thought is to tri-amp the system, port only the woofer cabs, and x-over at around 125 Hz, perhaps in mono at these low freqs. Your thoughts on this could be most helpful and influential...