Not to derail this thread too much, but on the same lines - I'd love to see a two-way crossoverless El Camino with an efficiency more like Zu Audio speakers, approaching 100db.

I think that sounds like what you guys are talking about as well.


So, I've been beaten up by work a bit this week - software update didn't go that well, and I'm still helping pick up the pieces today. Last night I fired up the ZMA with the El Camino speakers for the first time in a few days, and WOW! I don't know what changed...maybe further break in...maybe taking time away from music for a few days, or the planets were in alignment...but damn these sounded good! I went through my whole "demo tracks" folder that I test gear with, same tracks I treated people to at Decware when Steve let us sample the OTL amp, which I had connected to the prototype El Camino speakers - usually I get bored after a couple tracks and dive into my digital music collection; often grabbing something that a friend gave me or something I picked up on a whim or recommendation but never got around to listening to. But last night I dug in and listened to my whole demo tracks selection, from beginning to end...not just the good parts of tracks, or certain songs, but beginning to end...even all the way through The Planets Mars and Fanfare for the Common Man.

It's nice to have your system surprise you just when you thought it was getting kinda "been there and done that". The only thing I can figure is the speakers are still breaking in and last night was a step in the right direction. Seriously, it was such a great change in upper mids and treble, that I had to ask myself if I swapped out tubes on the ZMA and forgot that I had. LOL

Dry fitting the parts, making sure we're on target, and getting a feel for the layout. Lookin' good!




Laying out the carpet lining for the horn throat. Not sure how this helps honestly, but as the saying goes, In Bob We Trust.




Looking good here as well.





Tops and bottoms, keeping everything super straight and perpendicular. Again, Bob's cuts are beautiful.




Getting parts glued in place on one side. You can see the main chamber ports into the throat of the horn. I got the binding posts and wiring in. I used 10awg Zen Styx for the short run from the posts to the Xover.




Here I'm getting the sides put together. I've stacked the two cabinets so they help press each other flat, and I've added some 2X4 on edge to help spread the pressure from the clamps.

Dry fitting the braces, and sizing up the speaker baffle.




This is all the stuff that goes inside the speaker chamber. I'm not familiar with this buffalo board - I've never seen it before this build. Bob says it's key to getting the speakers to sound right.




Getting there!

Again, I have a lot of respect for Bob's skills as a woodworker, designer, and builder. These speakers really sound great now that we have them dialed in. I really do look forward to seeing "finished" production models. Maybe at the next Decfest I'll bring mine and compare them to Bob's production models and see how close to his they sound. I followed his guidance as much as I could (remember, we basically built these over the phone! LOL), Bob's cuts are beautiful, and I was really careful with my assembly - everything just lined up if I was careful. It's obvious from his finished products he knows what he's doing, but seeing these from the inside out, piece by piece, I'm seriously impressed...and I'm a picky bastard.  :)

Great work, LR & Palomino! Glad it turned out well for you.

Fantastic work fellas.

JD

Ohh, that reminds me, speaking of the HR-1, Bob said the Buffalo Board was essential to getting the HR-1 to sound right as well. So everything you see going on here is a culmination of his experience over the years.

Quote:


I'm hoping Bob can tune in and offer his thoughts, but I know he's really busy lately. I think he might be moving his shop even.

Ok, please keep in mind, I'm not a speaker designer, and my info is outdated. When I was in my early 20's I did do some designs, but technology and especially speakers has changed a lot since then...but the basic physics is still pretty much the same. Plus most of my experience is with subs, most of the airspace talk below doesn't affect tweeters.

Efficiency starts with the driver. You can't make an 88db efficient driver a 95db driver with a good cabinet design. Horns I think might be an exception to this, but there are a lot of tricks and requirements to what the driver can do, and limitations as to sound. I've heard speakers get really loud when setup in a horn, but then they sound "honky" or have "the horn sound" (in a bad way).

The airspace behind the driver is specifically tuned to the drivers. The airspace behind the driver is basically part of the suspension. If you put a driver that needs .5 cubic feet of airspace into a box that's only .25 cubes of airspace, then the suspension behind the driver is too tight causing efficiency issues and frequency issues, and probably running it hot. If you have too much airspace behind the driver, then the suspension is loose and the driver can be floppy and less accurate.

So you can't just take one driver out of a cabinet design and drop another driver in. That driver is expecting a certain airspace behind it. Will it work? Sure. But will it work *right*? Probably not, unless the specs happen to be close.

Add to all that, the ports are tuned to the airspace in the driver chamber to work with those specific drivers, and the ports and horn need to work in harmony, in the correct frequency range and pressure  as well. So you have to pick drivers, design a chamber, port the chamber, and design a horn to work with the driver, airspace, and ports and all in a frequency range that's "flat".

Crap it's amazing that speakers work at all, let alone work this well. If it's done right, a lot of math is used to get you a good start, but an experienced speaker builder takes the guidance from the math, adds his experience, then builds, listens, measures, and tweaks till it's right.  Hell, I think Bob said it took a decade to get the HR-1 right!

All of what I've said above doesn't even account for crossover, phase, and timing - which is all it's own complex thing.

So efficiency starts with the drivers and proper speaker design. The cabinet can eat up or enhance some of that, the crossover eats up some, and your room can enhance or eat up some. But it all revolves around what your speaker starts at. If you need 100db end product, then your drivers better be around 100db to start with.

For example, Palo and I were talking about this tweeter on the El Camino, and how different it is from the one in the 944. I do miss some of the high end extension and "air" the 944 has over the El Camino - but I'm glad to give up the slightly edgy, almost sibilant high end for the silkiness of the tweeter in the camino. But out of curiosity I started researching to see if maybe there was a better tweeter for the El Camino that would get me both that high end extension (40Khz), but still be silky, still go down to the FS of 650Hz that the new tweeters have (they are crossed over as well by the way), and still be 94db efficient or better. Six friggen hours of searching on the web, and I couldn't find anything under $350 per tweeter that was close to the specs I wanted! And even at $350 there were some trade offs. So it's pretty amazing to find all these parts and make them work together in a configuration that sounds good. The Math is only part of the trick.

As with everything, there are trade offs - so everything mentioned above, and lots I didn't, and lots I don't even know - all culminate in speaker building. This is why I didn't really get into speaker building as a career. LOL

Thanks for the enlightening explanation, Lonely Raven. I had the suspicion it was not going to be that easy.

Yet, I assume once you have a successful speaker cabinet design for a given set of drivers, you have already nailed the concept behing the successful design. That is, it may be a matter of scaling the new drivers' specs into the relevant mathematical models and come up with the right post-chamber specs and all the other dependent variables, including air flow patterns and piping dimensions scaled in relation to the original design (a purely deterministic calculation).

This exercise would consider and incorporate the new demands and characteristics stemming from the new object set of drivers. Finally, some trial-and-error tweaking with the right set of trained ears would finish the job.

I'm not saying it is easy, I'm saying I can envision the process and wonder why won't we take a succesfull existing speaker design in the low 90's sensitivity range and research for the ideal set of faster and lighter drivers and go through the mentioned (overly simplified) process until we achieve, say, a theoretically feasible 100+ Db at 8 Ohms.

Maybe this is the way it works for those speaker building experts, as one would have a quite convenient and informed starting point that would otherwise take a long time to arrive at if you started from scratch.

Excuse my rant, I'm just excited about the topic and very interested in learning about the SQ tradeoffs when pushing traditional speaker design into higher sensitivity levels.

Thanks

Lin,

I know, I was just suggesting to our Decware group to do it too. Voicing the speakers with our smaller amps in mind would make it so much more adequate. Thanks.

Correct, but these are more oriented to the moderate and higher powered Decware amps. The smaller ones are not having a really fair speaker choice at those borderline sensitivity ratings.

I wish all that talent was steered also to this niche within Decware. It is a pitty to limit all what a low-power SET or SEP could do in a more friendly speaker setting, including specific voicing.

As far as tradeoffs, I would love to learn what exactly are those ... tone, timbre, naturalness, musicality? There must be a price to pay for higher sensitivity somewhere, I just don't know which this is. Maybe understanding this would justify the current offerings.

Just my thoughts.

Yeah, the soundstage thing - I looked up the off axis frequency response on those tweeters compared to the ribbons we have in our other speakers, and those new tweeters drop off like a valley in the off axis. I can see how an almost straight on setup would help with that, especially if you have your poly-diffusers back on the side walls.

I certainly broke them in as well. I've put many hours on them, both with the ZMA, and with my Home Theater setup. They didn't sound bad right out of the box, but they sound more effortless now. I miss a little of the high end detail and extension of the MG944, but I like the silkiness of the El Caminos more I think.

I'm not sure what's going on with the production models of the El Camino. I still have the pair Palo and I built, and I know Steve has the original silver pair seen at Decfest last year.

I still like the speakers, in fact they are probably replacing my Zu Omens as my Home Theater speaker.

I know Bob was looking at moving to a new house, and therefor moving his shop where he builds speakers - hopefully he's moved in and getting the new shop settled in.