Fully committed, breaking the rules, and embarking on my ultimate dream project...

[Greggo]

Ready to take any final last minute advice before I start my project thread. I am breaking many rules... I am a complete newbie to building speakers even though I have been lurking here and on many other forums for more than a decade now. Despite that, I am not starting with a sensible project, I am starting with what I consider a potential state of the art "end game" project, for me at least. And I am cheating... I don't want to do any soldering (though I have done a little in the past on repairs and other electronics) and learn any tools around passive crossover design and implementation, so it is straight to miniDSP 4x10 Hd for me.

After roughly 50 concept designs on paper over the last two years, here is my current path, drivers on order and prepping my garage for a prototype build for DIY Iowa:



I will spare you the long story of how and why I ended up here, but many thanks to those of you who have advised me on various issues over the years and especially some folks on this forum who have been patient and especially helpful over the last few months.

If you find any of this interesting, keep your eyes out for a project thread that I will start very soon even though I haven't made any saw dust yet. I will be diving into more design objective and concept details, driver porn, and then MDF pocket screw prototypes. I figure that I will need a bit of luck to get things sounding decent by October, but can spend the next year or two learning how to fine tune digital crossovers and possibly even upgrade to more DSP power and better DACs at some point. For the time being, I am thinking of just using a Dayton MA1260 for all the testing and near term listening. I am hoping that I get the driver combo and cabinets right, and then enjoy tweaking to perfection over the years to come. This is my first big step into the digital active future that I believe is inevitable in the pursuit of maximum performance.

[[email protected]]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

WOW! I really look forward to seeing these!

[Pete Schumacher]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

Wow Greggo, ambitious project!!! Nice set of drivers for sure. Dual NE315!!!

The only "issue" to me is how low you have the tweeter. That might tend to pull down the staging somewhat since most of the directional queues are in the upper octaves. Then again, it may not be much of an issue once its in the final listening space.

I sure hope I can get to Iowa to hear these. WOW.

[kenny_k]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

Your on afterburners, can't wait.

[Greggo]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

Wow Greggo, ambitious project!!! Nice set of drivers for sure. Dual NE315!!!

The only "issue" to me is how low you have the tweeter. That might tend to pull down the staging somewhat since most of the directional queues are in the upper octaves. Then again, it may not be much of an issue once its in the final listening space.

I sure hope I can get to Iowa to hear these. WOW.

Well, I did say I was breaking some rules... and by going with a basic MDF prototype cab for testing I can breathe easy if things don't work out. Not completely original of course, but looking at some designs I have heard that I really liked... Mission, Linn, DeVore, and especially Dynaudio have all done the inverse driver stack at one point or another. The Dynaudio Consequence being the most radical effort, and the Contour S5.4 being the most practical and seemingly well received effort. Granted, all of those examples are driven by desire for phase and lobe steering that has a downward tilt that is corrected by inverting the drivers vertical positions. I am going active here so why this particular design? Because I like how the vertical alignment works out and the general asymmetry, the very different impact of floor and ceiling bounce, and just being a bit different. Jeff mentioned that he liked the Satori tweeter a bit off axis, so I will see just how far I can take that. I have the Satori mid at my planned ear listening height, 39 inches, and then with the step lower for mid and even lower for tweet I am curious to see how it all blends and how much signal delay I will end up building into the DSP crossover.

This whole thing is half science experiment for me and half industrial design exercise... I am trying to create a super model with brains and like many who chase such things, I may end up broke and disappointed

[Greggo]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

Another rule I am breaking is the double stack baffle, pushing the midbass, mid and tweeter out in front of the woofers (1 inch thick baffle on top of the 2 inch thick main baffle with woofers) rather than behind them to better line up acoustic centers. I am doing this so that the mid and tweet "see" a narrow baffle (at least for a few milliseconds) while the woofers get the wide cabinet and air volume they need (going with a sealed design here). I am not sure how this will play out either... I may end up running the dual 12s up past 300 Hz and the DSP timing thing may create more problems than it solves... who knows? I just had a bunch of different ideas and inspirations and I created a design that meets my definition of a big and dynamic flagship kind of design while still being small enough and interesting enough visually that my wife is game for keeping the finished product in our family room (no basement banishment, that is a major victory for me and my typical hair brained ideas).

[6thplanet]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

They look cool enough, and as a bonus the 12" Vifa woofers are on sale in the newest sale flyer. Good luck on your venture!!

[craigk]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

not exactly the same thing, but you might want to take a look. http://en.charioworld.com/serendipity.html

[youknowyou]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

why the nedd of a 2 inch mid? what are the XO points?

[ngjockey]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

You got brass ***** tackling that out of the gate. I'm working my way up the ladder but mostly sideways.

That got censored. Funny, because I just bought threaded aluminum ***** for speaker feet.

[Paul K.]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

I like the proposed looks a lot but that tweeter, as Pete said, is awfully low. I wish you all the luck in the world and I think you're going to need it even with an active crossover.
Paul

[Greggo]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

not exactly the same thing, but you might want to take a look. http://en.charioworld.com/serendipity.html

Oh, very nice... thank you for sharing that Craig. That is a nice addition to the general info collecting I am doing on this type of design.

6thplanet - yep, the sale price is what nudged me to a final decision and had my credit card jumping up onto my desk.

youknowyou - I am going to do some experimenting with this mid in and out of the lineup in a crude cab to see what I think, but I am basically going completely 180 degrees from my initial plans (waveguides and narrow constant directivity). I have come to the conclusion that dynamics and very clean high SPL are extremely important to me, so I want drivers staying well within their passband. Then on top of that, I have an unfounded personal bias regarding dome tweeters being matched up to cone woofers (everytime I hear a good system with a mid dome in the mix, there is something special that resonates with me personally so I have paid attention to that sensation, along with the general sense of ease and authority that get from large floor standing speakers). Small midbasses help, but I want the power response transition to be as seamless as possible.

I was starting with the Vifa NE149 or NE180, but then decided to just go Satori and have no regrets. And this drove the decision for the Vifa NE315 as woofers due to design, materials and "looks" that I think go perfectly with the Satori midbass. Since it is just a 6.5 inch midbass, I want to keep it well away from serious excursion so I wanted more than a "sub" running up to 80 or 100 Hz, hence the decision to go with the Vifa NE315 which I think will be very capable and musical up past 500 Hz if need be. So my target here is 200-300 for crossing from the dual woofers to the single midbass.

Then I wanted to remove any risk of response blips and directivity changes from mid to tweeter, so I am using what I think will be an excellent "low tweeter" in the EM1308... targeting 800-1000 Hz as the crossover point there to keep the Morel far away from any trouble down low and have all kinds of flexibility in picking a point to cross up to the Satori tweeter. I am not concerned about C-T-C spacing between mid dome and tweet even if I end up crossing above 4 kHz, but in the back of my mind I am thinking it will be more like 1.8-2.4 kHz, somewhere in that general ball park. As nice as the Satori mid bass is, I just don't see how it can compete with the EM1308 in terms of a perfect hand shake with the tweeter. I picked the Satori tweeter because I am one of the few that prefers domes to ribbons/planars, though I have not heard the RAAL or the latest gen air motion stuff. But Dakota DIY sealed the deal for me, hearing a few SB tweeters, I just love the personality of those drivers.

[Paul K.]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

My post sounded way too negative and that wasn't intended. I've been where you are many years ago, as have others on occasion, taking on a very ambitious design as the very first DIY speaker project. I do hope you are very successful, and if they end up looking at all like you propose, in addition to sounding good, you should be very happy.
Paul

I like the proposed looks a lot but that tweeter, as Pete said, is awfully low. I wish you all the luck in the world and I think you're going to need it even with an active crossover.
Paul

[Greggo]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

Hey, no worries Paul. I know I have ventured out onto thin ice here, and I haven't even earned my skates yet. So any concerns or warnings from guys like you or Pete and others are very welcome and I would like to think that I will always take that in and interpret it correctly. One of the things that makes me feel really good about this project is that I know these drivers are capable of working extremely well together, with maybe the EM1308 being the only real risk here. So once I invest in the miniDSP and Dayton 12 channel amp, the only thing standing between me and multiple alternative 3 ways designs is a bit of MDF or plywood. That is a small price to pay for the privilege of playing around with great drivers and doing some things that are a bit original and some things that have clearly been highlighted by others who pave the way. In this regard, it strikes me as a very low risk proposition.

[Paul Ebert]

Re: Fully committed, breaking the rules, and embarking on my ultimate dream project..

This looks like an awesome project. My first project was really ambitious. I found that as long as I was patient, things worked out fine with all of the support available on this and other similar forums.

I'm contemplating a similar design. The NE315 has been one of the woofers on my short list, but I'm concerned about the 6 dB drop between 30 and 40 hz. Since it's reflected in a small bump in the impedance curve, I wonder if there isn't also a rise in the distortion. As anyone seen a distortion plot for this driver?