The Navvy

Thanks, speakerfritz. Your web page has been very helpful too.

There. http://www.theavspot.com/atlas-sound-pd-5vh And I can find a red one too. What gives?

"$100 online" Atlas Sound PD-5VH Compression Driver 40 W, 16 Ohms Model PD-5VH is a 40-watt driver with 2" voice coil machined to optimum tolerances. Model PD-5VH has an Alnico V-DG magnet which offers maximum temperature stability and optimizes output for yielding the lowest amplifier power requirements. It also provides terminals for matching direct to the 16 ohm voice coil. PD-5VH offers a plane wave frequency response of 110 - 4,100 Hz (+5dB). The durable compression driver mounts easily to large format horns that terminate in the standard 1 3/8"-18 male coupling thread. Trying to upload image. With fins. Help?

Why do some Atlas PD5VH drivers look different from the grey metal ones that are exact replacements for Klipsch K-55V or K-55X? Are they different in any way other than aesthetically? Some have fins (heat sinks?), some are red (looks like plastic body), some are grey metal body, some are black... All 16 Ω, 40 Watt. My question is: ARE THEY ALL THE SAME? OR IS THERE SOME DIFFERENCE other than cool looking fins or red or black or grey color?

It seems I have not defined my question clearly, or else terminology is all that is confusing me. I'm looking for a horn that can reproduce a (high-pass) frequency range above around 600Hz. I am only concerned with the horn's ability to reproduce this frequency. Given that: A high-pass cut off frequency of 400Hz needs a larger horn than a high-pass cut off frequency of 600Hz (the lower the cut-off target freq, the larger the horn). And: A high-pass cut off frequency of 400Hz needs an acoustical cut-off of the horn to be around 200Hz, and a high-pass cut off frequency of 600Hz needs an acoustical cut-off of the horn to be around 300Hz (always a factor of 2), should I be looking for a horn with a 300HZ cutoff listed in its specs, (that's a big horn, larger than an Altec 511B) or are the specs NOT showing me the horn's ACOUSTICAL cut-off, but the lowest recommended frequency the horn can reliably reproduce?

Say I'm building a 3-way CornwallScalaThing with a crosover from the woofer and midrange arond 600Hz, using a K55M (Atlas PD-5VH) driver. Forget about everything else but the midrange driver and horn. I have K55M drivers. What horn am I going to use with them (Bob asks)? Good question. I don't have an answer. The Corwalls used a K600 horn, but wht does the "600" designation really mean? A lot of people seem to be looking for the Pyle Pro PH2380P horn for these drivers, as a replacement for a K600, but they're no longer available. The PH2380P's specifications state: Cut Off Frequency: 500 Hz Mounting Type: Copper Screw Insert 1 3/8" - 18 UNEF Throat Diameter: 25.40 mm (1") Dimensions: 8 11/16'' (H) x 17 5/16'' (W) x 10 3/4'' (D) (are these dimensions close to a K600's? It is my understanding that a high-pass cut off frequency of 600Hz needs the acoustical cut off of the horn to be around 300Hz. (factor of 2). So, when I am reading a horn's specifications, it seems to me that it would be its acoustic cut off frequency that's in the specs, and this PH2380P horn would only support a crossover frequency at around 1KHz or above. Hopefully I am interpreting the specs wrong. Don't say "Ask Bob Crites" because he's already helped me enough already. ( Read ENOUGH ALREADY! ) He's really been great, and he has used this Pyle horn (but can't get them any more). The cut off spec really perplexes me. I found and bought a Pyle Pro PH2380P for this project, but the 500Hz cut off in the specs is confusing the heck! out of me. What the Heck! ?

The schematic you sent is an AA . Substantially different from A? Is there a library of Klipsh Heratage crossover schematics available somewhere in the Klipsch community? I'm going to need at least B, E and A schematics to do the conversion. Thanks for your attention.

Once again, speakerfritz came through with greatly useful information. Thanks again. If I stick with converting my B and E xovers to A type and stick with K77or K77M, will it nullify the whole 16 ohm HF driver problem? What will be my xover frequencies if I convert to type A? 600Hz and 6000Hz? And I may be asking a dumb question, but are E, B and A networks all Butterworth filters? 6 dB/octave roloff? Did Klipsch use any L-R networks with a sharper rolloff in the Heratage line?

For mid drivers I have one extra aluminum horn from a Heresy and I plan on buying a K55V. That will take care on one of them. Same for the other, hopefully. But this brings up the difference between a Cornwall horn and a Heresy horn. Cornwalls are a bit bigger. Is bigger a better match for a 15" woofer and a 600 Hz xover point than the Heresy's 700Hz horn crossover? Oh, you say "convert the Type B and Type E to a type A crossover." Easy peasy, or send it to Crites? The B and A look VERY similar. I think I could do it myself with the right parts.

I plan on adding a squalker and a tweeter to two EV design folded horns (15" speakers- well blown out) that I built 36 years ago. I'll probably go with Crites for the woofer. I have one each (extra) Type B and Type E crossover. So I'm looking for compliant mid and high drivers. So what I'm really asking is: Will a 16 ohm driver damage my old Klipsh xovers? My mid 70's Heresys are great, but I need to have a lower low frequency reference (I know-- buy Cornwalls-- I've been looking!).

Wow! Now THAT'S expounding! Thank you. Now I'll have to look inside my 1975(?) Heresys for the first time. What I'm eventually driving at is adding a squalker and a tweeter to two EV design folded horns (15" speakers- well blown out) that I built 36 years ago. I have one each Type B and Type E crossover. So I'm looking for compliant mid and high drivers. So I guess what I'm really asking is: will a 16 ohm driver damage my old Klipsh xovers? Maybe I should post a new post. Thanks for taking the time to answer in such detail.

ATTENTION: speakerfritz answered all my questions and more re T85, T85B, T85A, K77 and K77M. Amazing. So I started a new thread re connecting 16 ohm T35B to my two extra Klipsh xovers. ------------------------------------------------------------------------------------------------------------------- I think I have read on a post here that the K77 and T35B are the same thing (although quality may differ, as there seem to have been some rejected and returned to EV by Klipsch). The contemporary T35B's I've seen are 16 ohm. Weren't the K77 and K77M 8 ohm drivers? I've also read (somewhere else, I think) that the T35 (no "B") was a real ugly sounding HF screamer, compared to the "B". Can someone expound on this (mis)information?

Thanks, oldmako and oldtimer, for your replies. Can either of you direct me to a cabinet plan or pic to show how and where the passive is mounted? May be a good experiment to boost some bass out of 10" woofers. I do not have the KG4, just the KD12 passive.

Passive Radiator KG4 KD-12 Can someone please help me understand what this is? I thought it was a 12 inch woofer that I would have use for sometime somewhere. But I'm starting to find out that it is not a driver, and may be a sympathetic resonator of some kind for the KG4 line of speakers. But they had 8" speakers, I think. I have two Heresys (1's E xo), an extra E xo, and a B xo. I'd like to build (or find) a Cornwall (or two). I need something w/a 15" woofer for mono reference or reverb chamber. The Heresys could go to the chamber if I find two Cornwalls, but I'm getting off the subject. What is the function of a KD-12, and should I cut my losses and just resell it or is it something I can use experimentally? BTW, I'm a newbie to this forum, so if I'm in the wrong place, let me know. Tom the Navvy