Crossover questions

Thanks for all the responses. Sean, I think I will contact Clayton for his expertise and opinions on series crossovers. I will probably also get in touch with Bud Fried. Herman, I will check out Gizmo's ideas. I have considered horns, but have never really fell in love with them. I do have a pair of horn speakers in my living room that my father built in the mid 1960's. They are exactly as you suggested. The sound of them is pretty good. Perhaps, I will give higher quality horns more consideration.

I am not at all interested in a 5 channel HT setup, and expressed these feelings explicitly to my girlfriend. She has no problem with this, and basically just wants to have a nice looking setup in the family room. One where we can watch tv and she can sing karaoke. Whether my woodworking skills are up to the challenge(to make something "attractive") is the question. Her reasons for wanting a good amplifier/speaker arrangement are completely to appease her boyfriend, who happens to be waaaayyy too serious about audio.

As far as the excellent speaker questions that were raised, here are my rapid fire answers(sorry for my lack of clarity in the initial statements)... I was stating that the midranges(or mid/woofers) be run flat out(no caps, coils, or resistors), and wired in series in an overall parallel crossover network. Wiring the entire loudspeaker in series would preclude me from keeping components out of the path of the midrange drivers. Rgreene2, Triangle(glad you mentioned them) is one of the speakers(along with Eggleston and personal experience) which have proven to me the benefits of running the midrange or midwoofer with no crossover components in the circuit. In my parallel crossover approach, the tweeter would have a film and foil capacitor wired on its positive leg, and a resistor(if needed). As far as woofers(in the strict sense of the word) go, I am still undecided. They suck a good deal of current. I may just build these speakers with nothing larger than 6.5" drivers. If I later decided that I really needed to have that last octave, I could go with a pair of subwoofers.
Still have a lot of thinking to do... Things like do I use a REALLY dead cabinet, or more loosely damped(that everything old is new again thing)? I'll decide that after I figure out the crossover, but have always felt a dead cabinet was the way to go. Double thick walls(featuring MDF and plywood), with a layer of something between them(Swedak, viscoelastic, or other polymer), corner braced internally, and BlackHole 5 on the inside walls.

Joe, apply your "deader than a door nail" speaker cabinet theory to the horns / horn bodies on your dad's speakers. Keep in mind that some horns have some type of screen / mesh "diffusor" in the throat near the driver. If that is the case with those specific speakers, remove them. Most of the glare / ringing that you hear from horns can be directly attributed to the resonance of the two culprits i just mentioned.

As to using "Black Hole" (which is quite expensive in large quantities) for damping / deadening / mass loading, try using "damping sheets" from Parts Express. MUCH, MUCH cheaper and it will do at least 80% of what you're looking for. I'll snag a part number later should you or anyone else need it. Sean
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Thank you Sean! I will think about horns in a more thorough light. The cabinets of my father's speakers(horns with cone woofer), while excellent for their day, can be improved in several ways. Also, the quality of the passive parts(coils, caps, resistors, and wire) have improved quantum levels since those speakers were built. I will also take your advice about the "diffusors" to heart.

You are quite correct about the cost of BlackHole 5. I once made a few "sound boxes" at my previous company. We manufactured EL(electroluminescent lamps), for use in cell phones, pagers, night lights, etc. The whole technology is simply a capacitor that lights up when supplied with AC voltage. There was a lot of noise generated via the AC voltage(coming from the inverter)/lamp. My job was to get rid of it. I looked into anything I could. The sound boxes were just basically speaker cabinets we built(minus the speakers, but with a window to view an inserted SPL meter), which insulated the lamp/meter from the ambient noise of the plant. Got lots of wonderful experience with sound insulation materials. Things like acoustic foil, SoundCoat, foams of every sort, viscoelastics, rubbers, silicones, polymer formulations I developed(applied via screen or pad printing). In the end, the best solution was to simply screen print a third electrode(using my carbon resistor paste) which served as a "shield".

The experience of building those boxes and insulating them(with foams, SoundCoat, foils, BlackHole Pad, BlackHole 5, Swedak, etc.) was invaluable in teaching me about quieting down a box. Materials were free(either sample or out of the company's money), and I was being paid. BlackHole 5 proved to be an excellent product(I like the viscoelastic/multiple foams combination), and we did end up buying a bunch.

To be honest, I can(and probably should) build that BlackHole 5(or better) using viscoelastic sound panels(probably the same as the sheets you are getting from PartsExpress), and two kinds of foam(from Foamex or whoever) for a fraction of what Orca's retailers charge for it. Even incorporate some acoustical foil(very effective stuff) in the my homebrewed insulation.

Now I get to use all of that information! Speakerbuilding is an immense subject, and no one has all the angles covered, but it sure is fun to play this game. If you are going to be undertaking a similar project in the future, it would be great to bounce a lot of ideas off each other. Again, thanks for your help.

Sean by the way, I just came across a thread on Tweaker's Asylum from 'Clayton Oxendine' regarding a series crossover question(via web search on "series crossover"). So, I now have found at least one person in the world who has knowledge of this mostly forgotten technology. Again, thanks for your help in steering me toward this person!

Trelja, e-mail me and we can discuss speaker design sometime, if you like.

My opinion is that series crossovers aren't a "forgotten technology", it's just that they are difficult to design, and are very unpredictable (very difficult to model with computer programs). I believe Joseph Audio's legendary x-overs are series, and his are supposed to be the steepest in the industry. The Stereophile review measurements confirm it, too. You can bet he hasn't "forgotten the technology".

I have two suggestions for you to check out:

First, if you like connecting speakers directly with no crossover, consider building a system with Fostex full-range drivers from Madisound (similar to Lowther, but much cheaper). At least visit their site and take a look at the drivers, and their flat frequency response. I've never heard them myself, but I bet they're worth the money, wheras the Lowthers are insanely expensive!!

Or second: Consider the Bottlehead.com speaker kit. They connect a bunch of aluminum coned midwoofers in series-parallel, use a high sensitivity tweeter (looks like a Focal clone), and the sensitivity is around 95 dB. It's an easy load to drive.

If I didn't already have several speaker projects going, I'd have bought the Bottlehead one immediately. I'm actually trying a project of parallel midwoofers. it will be a more difficult load to drive, but with these particular ones, it might work. I hope to use two tweeters in parallel per channel, and the sensitivity should be around 96 1w/1m. The catch is that the cabinet will be quasi-dipolar, and I'll augment with whatever powered subwoofers I have on hand...currently the Sunfire.

I just bought some Infinity Emit ribbon tweeters from Speakercity.com for only 40 bucks a piece, and they're simply incredible! I bet they're 99% of the performance of the Raven R-1's, at least until you get closer to their thermal limit.