[matevana]

Matevana if it is not akin to asking the alchemist how he makes gold, would you mind describing the process you went through to design the crossover?

And also, what's next?

Really nice job on your Hestia build! I imagine the elevated height of the top driver pair makes a big difference in your environment. I'm sure you will have many happy hours of listening.

I tend to cheat a bit in coming up with crossover designs. I used to start with formulas and then tweak, but while this worked effectively in ball-parking component values, it did little to actually sample the drivers in their respective ranges and determine the best operating range, minimal distortion and power curves for each. In fact, a dipole's rear wave can sound very different when sampling larger vs. small drivers operating over the same range, if that makes any sense. Crossover calculators do not take these things into consideration.

Instead I use an Ashly 2001 active crossover to experiment with all the drivers on the test baffle. Within seconds you can alter crossover points, select from LR, Bessel and other x/o properties, and compensate for various driver levels. I spent days doing this with the Hestia, design, which is only a simple 2.1 way system. This is how I came up with the rather unusual crossover values, which at first seemed counter-intuitive (until you listen to the Hestias). I then attempted to duplicate these properties with passive components. Never would have arrived at the same conclusion w/o being able to sample and dial-in values on the fly.

[matevana]

And also, what's next?

Been hard at work for the past few months on the next natural progression for me. Inspired by the recent designs of the Linkwitz LX-521 and John K's Nao Note II RS, which seem more similar then they are different. It's encouraging to see how two of the best known OB guru's arrived at similar design conclusions after decades of experience. I'm currently playing with an interesting 4-way design. In a nutshell, the basic design goals are:

1) Tall thin panels addressing off axis response and imaging.
2) A unique H-Carriage to house the bass driver.
3) Active/passive hybrid.
4) Time aligned baffle design.
5) Advanced construction techniques (that anyone can replicate) minimizing cabinet vibration.
6) Form vs. function artistic concept.

I'm testing some interesting drivers right now. Nothing final but I'm favoring an Usher 8" driver in an incline-H for bass duties. I love the fast articulate response and it's ability to cross slightly higher than normal. A Peerless 6.5" aluminum driver for the lower mids. Still loving the inexpensive Vifa D-19 for the highs, this time crossed very high. Jury is still out on a critical 4-5" midrange which will round out the quartet. Right now I'm testing three drivers here; a CSS FR125, as well as a Seas 4" fullranger and a Scanspeak 4" driver. This design will obviously cost a bit more, but I'm interested to see it all come together. Sort of a big sister to the Hestia!

[Plund]

Matevana,   Soooo, If a bit more bass SPL was desired, using Sjhomey's build for example, one could throw another MCM woofer into the longer baffle without issue?

Pete 

[matevana]

Matevana,   Soooo, If a bit more bass SPL was desired, using Sjhomey's build for example, one could throw another MCM woofer into the longer baffle without issue?

Pete

Pete, the short answer is yes. If you were to do that, I would recommend using two plate amps, running in dual mono (separate left and right channels). The reason for this is not so much additional watts, but as you raise the woofer on the baffle it will likely become more directional. Also, since the MCM driver is somewhat limited in mid frequencies, the Hestia design is well balanced using one bass driver. So you will gain bass SPL with a second bass driver, which you may or may not end up needing. The plus side is that each driver will work half as hard, and you are likely to see performance gains as a result (less excursion = less forces acting on the baffle).

[Squidspeak]

Finished up a set of Hestias about a week ago. They sound great. I flush mounted the drivers which took quite a bit of router time, but overall a straight forward project. Also, I moved the mid/tweeter combo higher on a taller baffle closer to ear level. The sound between the HF and LF is very cohesive despite the gap in between.

Matevana if it is not akin to asking the alchemist how he makes gold, would you mind describing the process you went through to design the crossover?

And also, what's next?
SJ, looking good. My whole shop was totaled by the storm, so I was very happy to see the tweeters
I sold you in your project. The MCM woofers I got from you survived, but pretty much every thing I owned
was under 4 ft. of saltwater. Gotta relocate,but determined to build my Hestia's  Good day, Squid

[matevana]

My whole shop was totaled by the storm, so I was very happy to see the tweeters
I sold you in your project. The MCM woofers I got from you survived, but pretty much every thing I owned
was under 4 ft. of saltwater. Gotta relocate,but determined to build my Hestia's  Good day, Squid

Squid,

Sorry to hear about your run-in with Sandy. If I can help with anything, let me know.

[sjhomey]

Squid
I'm really sorry to hear about the damage to your shop. When you hadn't posted I was hoping that you were busy with cleanups and repairs in the area. I can only imagine what you are going through. That was one bad storm. Speaker building pales in comparison. We were lucky here. The eye passed over us and it was still for two hours and then hit with a fury from the south for the rest of the night. But flooding damage was relatively light. I hope your home fared well and you are able to put things back together, in time, at your shop. I am sure it will make doing business very difficult for some time. My best to you and your family.

Peter

[Squidspeak]

Thanks, Pete  It really brightened my day when I saw your build. Looks great BTW
House and family OK, just a nightmare with the shop and boats. Gonna move shop Inland
so When I get set up and running I'll get back to my hobby/passion.
   Thanks for your concern,  Squid

[Squidspeak]

Pete, what's next for you. The Hestia SL. BTW moved shop inland and will take a month to
set-up. Really like to have DIY event in June in new shop, South Jersey represent! OB, box,
whatever., Thoughts?

[newbie7800]

Dear matevana, sjhomey and Poultrygeist

I am living in Germany and want to build my first pair of speakers.  I have owned various speakers over the years including Rega floorstanders (R3s) and now Tetra 120Us.  I want to get away from the box sound and decided to go the DIY route but my DIY skills are not great and have been looking at open baffle designs these last few months.  Originally I was going to build Poultrygeist's last project with the Eminence Alpha-15A 15" Driver and the Neo3 tweeter but then I came across the Hestia OB and love the simplicity of this design and the fact I could use most of my existing kit (except for the need to get plate amps).

My existing equipment is as follows:

Dussun DS99 Integrated Amplifier http://www.dussun.com/english/ds99.html
Mapletree Audio Ultra4A Pre-amp http://www.tnt-audio.com/ampli/mad4multra_e.html
Musical Fidelity V-DAC II with Hiface 2 USB to SPDIF converter
PC with Vortexbox installed
Modified SL1200 MKV turntable
Tetra 120U speakers

A couple of newbie questions:

1) What size holes do I need to make for each driver?  I have access to a jigsaw so think I can manage cutting some circles.
2) sjhomey - can you give me the measurements of your entire baffle and the driver heights. Thanks.  For someone with relatively zero woodworking experience how difficult would it be to flush mount the drivers?
3) What do you use for the seal of the drivers to the baffle?
4) What about screws for each driver? How tight should the screws be?
5) I can solder but I am pretty dumb when it comes to reading circuit diagrams.  Would you be able to post one or two “looking from above” shots of the crossover. 
6) Are there any better alternatives to the tweeter in terms of sound quality given the relatively low cost of this project? Crossover impacts?
7) sjhomey - what binding posts did you use at the bottom of the baffle?
8 ) I was thinking the Dussun could drive the midrange and HF drivers.  Do you see any issue with the set up?

Many thanks for all your collective help.

Newbie7800

[Rudolf]

Danger
In the above post the adress www.dussun.com leads to a trojan virus in Romania

[newbie7800]

Hi Rudolf

I just googled Dussun to find my old amp and copy and pasted the link after checking it. I have AVG installed and it did not identify a threat. Anyway the specs for my amp can be found by googling Dussun ds 99 and Goodsound.

Will check my machine tonight. Thanks for the warning.

Newbie 7800

[Rudolf]

To be exact it is http://www.dussun.com/english/ only.

[matevana]

Newbie7800,

With regard to your question about tweeter alternatives, I have had good luck with the Vifa XT19 in the new Hestia-SL project. I would consider it an upgrade to the D19 due to it's dual radiator design and it's ability to be crossed lower w/less distortion. It is however a 4 ohm nominal design, so you would need to compensate for one coil and cap in the current crossover design. If you decide to make the change, the Hestia will still maintain the same signature as the two Vifa products are voiced similarly. 

Take a look at the Parts Express and MCM websites for overall driver dimensions and cut-out dimensions. If you are not familiar with routing recesses, I would recommend just surface mounting the drivers. Within the context of this project, the off axis frequency response will not suffer all that much by not flush mounting the drivers.

I hope that helps. 

[newbie7800]

Dear Matevana

Thanks so much for coming back to me and helping me start this journey .  Had no idea the cut out dimensions were mentioned on the driver pages.  Sorry.

On the tweeter, this sounds good but whilst I understand what you mean by coil and cap I have no idea about what "compensate" means in terms of implementing the change to the crossover design.  Sorry, I am really starting from scratch here.  Any support you can give here would be great.  Thanks.

Would you mind pointing me in the right direction for the following two questions:
(i)What do you use for the seal of the drivers to the baffle?
(ii) What about screws for each driver? What type and how tight should the screws be?

I will take your advice about the routing .

Thanks for your support.  I really want to give this project a go and I just need a push in the right direction

Newbie 7800

[matevana]

Newbie,

If you take a look at the schematic in post # 13, you will need to substitute two of the components to accommodate the lower nominal impedance of the XT19 tweeter, namely capacitor (C2) and inductor (L2).  Some good ballpark values would be obtained by doubling the capacitance (to around 11uf or 12 uf) and halving the inductance (to around .70 mH). This will get you real close to the original intended crossover points of the D19 tweeter. The two tweeters are close enough in sensitivity where you should be OK just by swapping the two components mentioned above.

Parts Express is a good source for driver mounting hardware. They sell self adhesive gasket material but open cell foam type weather strip will also work well. While this may be  more of a factor in closed box designs, (to prevent air leaks) it's still good to use foam to help prevent any mechanical noise from occurring when the driver comes in contact with the baffle. I use black pan head wood screws to mount my drivers, either 1/2" or 3/4" in length depending on the frame depth and baffle thickness. I personally do not like T-nuts, and opt to screw the drivers directly into the baffle, though others may disagree. Torque the screws evenly by hand in a star pattern, to prevent warping the driver's frame. Hand snug should always be sufficient and it's a good idea to repeat the star sequence a day or two after the drivers are initially mounted once everything has settled-in. 

Please let me know if you have any other questions. 

[newbie7800]

Dear Matevana

Thanks so much.  For now I have loads of information to get started.  I may have a question or two once it comes to actually finalising the cross over but I will certainly use the info you provided first.  Will let you know how it goes.  Really grateful.

[sjhomey]

Newbie

The bottom of my woofer is 2" from the bottom of the baffle. The bottom of the midrange is 22" from the bottom of the baffle and the baffle is 35 1/2" tall. As Matevana has mentioned the important thing is to keep the mid/tweeter as a unit per his plans and to keep the woofer close to the floor. I raised mine to 2" and I think he has his at 1".
If you have a router flush mounting is relatively straight forward but very time consuming. I surface mounted my drivers on a pair of scrap plywood baffles at the beginning. I would recommend surface mounting and get the speakers playing and then worry about how you want to configure the finished baffles later. It is quick and cheap to do so.
I can post a photo of the crossover but I've included the parts list I ordered from Parts Express. If you buy the boards if is very easy to see where everything goes using Matevana's key which I think is on the first page here.
You mentioned buying two plate amps. Matevana's design calls for using 1 in mono. From what I am hearing that seems quite adequate. They are probably the single most expensive part of the project and only buying one saves a few bills. As you can see I paid $140.00 for mine but I noticed fairly recently they were on sale for around $100.00.
Good luck and keep posting.


QTY     PartNumber     Product     Price    Ext. Price
2    091-1260    Dayton Audio BAGS-G Banana Speaker Plug 2 Pair    $12.95    $25.90
1    365-255    Jasper Circle Jig Model 400    $26.62    $26.62
6    091-1245    Dayton Audio BPA-38G HD Binding Post Pair Gold    $8.48    $50.88
1    260-542    Speaker Gasketing Tape 1/8" x 1/2" x 50 ft. Roll    $7.64    $7.64
8    269-265    Rubber Cabinet Foot 1-1/4" Dia. x 1-1/2" H    $0.40    $3.20
1       Economy Shipping    $0.00    $0.00

QTY     PartNumber     Product     Price    Ext. Price
2    027-556    Solen 5.6uF 400V Polypropylene Capacitor    $4.23    $8.46
2    027-562    Solen 7.5uF 400V Polypropylene Capacitor    $5.51    $11.02
2    091-1045    Dayton RCAAD-MFF RCA Male To Dual Rt Angle RCA Female    $8.81    $17.62
2    264-500    Vifa D19TD-05 3/4" Poly Dome Tweeter    $16.88    $33.76
1    CATALOG    FREE CATALOG    $0.00    $0.00
2    255-258    Jantzen 1.4mH 18 AWG Air Core Inductor    $10.58    $21.16
2    255-264    Jantzen 1.8mH 18 AWG Air Core Inductor    $11.79    $23.58
2    260-130    Crossover PC Board 2-Way 12 dB    $3.70    $7.40
1    301-510    Yung SD300-6 300W Class D Subwoofer Amp Module w/6dB@30Hz    $139.88    $139.88
1       Economy Shipping    $0.00    $0.00

[newbie7800]

Dear sjhomey

Thanks!!!!

Thanks for the point about the plate amps especially.  I am going to get myself a router but will first mount everything on scrap ply as suggested.  Will only order everything after Christmas to avoid the Christmas rush.

Thanks for the help and I will post an update in the new year.

Newbie

[Plund]

I hesitated (hestiatated?) a few days too long to order from MCM...they show a 90 day back-order on the 55-2981 drivers.  I received all other needed components from Parts Express. Thankfully all is not lost...I will likely fill at least most of that waiting time finishing a pair of FH3's.

Pete