Hestia OB, an ambitious low cost, 3-way OB design

matevana · « **Reply #260 on:** 29 Dec 2014, 07:23 pm »

Newbie,

It's hard to trace the wires from the pictures you provided, but based on the following description you gave:

"I studied the various crossover postings numerous times before building the cross over but my complete lack of electronics knowledge is probably getting in my way. I have attached some pictures to see if anyone can help. Because of C1 and L1 in Matevana's design being for the MCM driver I thought that the plus connection labelled +T must be for the MCM and that the +W must be for the XT19. L2 and C2 are soldered to the +W connection (being 0.70 coil and a 12UF cap for C2)."

it is likely you have the low and high circuits going to the wrong drivers. In circuit board nomenclature, T+ indicates the positive side of the tweeter, W+ the positive side of the woofer. Based on the way you described how it sounds, the tweeter is getting the signal intended for the woofer (and vice versa) which would cause the tweeter to distort badly at all but the lowest of volume settings. Be careful here as you can easily damage the tweeters (but not the woofers) if you are driving them with a low frequency signal.

You can test this using only the woofer, as you will not damage it by feeding it either signal. Disconnect the tweeter entirely and work only with the woofer for now. First listen to the woofer the way you have it hooked up. You should hear mostly lower sounds with muted highs. Now disconnect the woofer and connect it to the leads that were formerly connected to the tweeter. Now you should hear a complete lack of bass through the woofer, with only high notes present. If you hear the opposite, you have the low/high circuits backward. The easy fix here would be to simply disregard what the circuit board says (since you have already soldered the components) and feed the drivers in the opposite orientation as to what you currently have. (You may need to adjust the length of the leads to reach the proper driver).

If you are completely stumped, I would be glad to look-at and fix the crossover for you. You can mail them to me, I will redo one and you can follow what I have done for the 2nd after I mail it back. I realize that isn't as immediate, but I'll throw that out since I know you must be frustrated!

newbie7800 · « **Reply #261 on:** 29 Dec 2014, 10:09 pm »

Hi Matevana

Thanks for the reply. If you look at the drawing this is how I wired the crossover. L1 and C1 as per your original instructions are for the mcm. However on the parts xpress board they are wired to the T+. Since L1 and C1 were for the MCM I thought regardless of what was on the board I should follow your picture showing L1 and C1 connecting to mcm. I tried before connecting the mcm driver to both outputs and the sound I got was muffled bass sound......

Looking at my drawing should the tweeter be connected to t+ even when L1 and C1 connect to it. This is what completely baffles me...

The distortion is also not even with 1 tweeter making more tHan the ever..

matevana · « **Reply #262 on:** 29 Dec 2014, 10:54 pm »

Hey Newbie,

L1 stands for inductor #1 and c1 capacitor #1 and are used to indicate the values of those components. They have little to do with the positions of the components that get inserted into the pre printed circuit board. The relationship of the two components is inverted for the woofer and tweeter, with the woofer circuit having the inductor in series and the capacitor in parallel, and the tweeter having the capacitor in series and the inductor is parallel. The circuit board does this orientation for you if you follow the wiring for the positive and negative terminals for the woofer and tweeter. In other words, the MCM gets wired to W+ for the positive and the Vifa goes to T+ for it's positive terminal. Without seeing the board up close it sounds like you have them reversed? It's hard to tell for sure in the picture since you have the same color combinations going to both the MCM and the Vifa, and they are coiled making a trace by eye too difficult from the photo.

Also, I noticed that the inductor mounted on it's side is about half the size as what is spec'd, so I'm guessing you made the adjustment for the 4ohm XT19 as opposed to the 8 ohm D19. If that's true, you definitely have the components soldered into the wrong positions, as that would be the slot intended for the woofer's inductor and not the tweeter. I'm hoping that makes some sense.

If it's easier to discuss this I can make my phone # available to you if you PM me.

Ed

newbie7800 · « **Reply #263 on:** 29 Dec 2014, 11:49 pm »

On the parts xpress board I followed the sheet that came with it and placed each if the coils and caps as per the instructions. However as I saw the L1 and C1 caps connecting to the same pad as the t+ this confused me as i thought it was like a pcb and could not figure out why L1 and c1 would have solder points on the same pad as t+. Dumm for those who understand the pre etched board but confusing for me.

Yes I did follow your instructions for x19 and at the top have 0.7 coil and 12 cap which link to w+ but I connected the tweeter plus there thinking the coil and cap connecting to the w+ pad where meant to be for the tweeter.

Will pm you in the morning. Thanks again.

brad944911 · « **Reply #264 on:** 5 Jan 2015, 05:04 pm »

Hey Newbie, first off...nice work

I hope ya have gotten it resolved.
If not, I looked over the pics and unless my eyes mixed the wires/diagrams, they are indeed reversed. Just remember in the high pass section of a crossover (regardless of slope) the cap is the first reactive device the signal will encounter; the low pass will be an inductor. Unfortunately ou will have to swap over all the components on the board to work. C1 will be the 12uf cap, L1 will be the .7mH coil; T+ will go to the Vifa's + term. C2 will be the 7.5uf cap, L1 will be the 1.8mH coil; W+ will go to the MCM + term. I'm using the XT19, too BTW and they work great.
Also, at first this set up did not sound great...in my opinion; good, not great. It took a few of weeks of many hours of just letting the speakers play to break them in. I made several adjustments to active crossover points and equalization all to have them sound like crap in the next listening session. Lesson here: patience grasshopper. I ended up pretty close to what Ed described: 20-90 Hz for 12" sub, 90-280 Hz for 10" MCM and 125-20,000 Hz for the MCM Vifa pair. Now they sound pretty darned good to me! I'm quite happy all the way around, as I'm sure you will be once you get the wiring woes resolved and the drivers settle in.
Best of luck bud!
Brad

newbie7800 · « **Reply #265 on:** 6 Jan 2015, 07:53 pm »

Dear Ed, Brad and SJHomey

First the good news...everything is working and sounding pretty darn good. A lesson for any beginner is to ignore completely the parts xpress labelling of the cross-over components and actually look at Ed's original drawing of the crossover circuit. Thanks to Ed for taking the extra time to talk me through this. 2 years of waiting and I am officially part of the Hestia OB family. I want to thank Ed and also SJHomey for their support and various posts going back 2 years even for the smallest of details like what were good screws to use. Also for SJHomey's idea to place the vifa/MCM drivers higher. Completing this project from Germany has not been easy but I am completely satisfied.

I cannot be sure I did not damage the XT19 in the process. I played a few tracks on my headphones and then through the speakers and could not hear any "damage" but the XT19s excursion was crazy for a while when I had them connected incorrectly although luckily I turned them down when I heard the distortion originally. I may end up replacing them in a few months to end my paranoia.

I want to thank Brad also for his last post. I am very pleased even with the XT19 in its post abuse state. Detail levels are very pleasing. I have played them as much as I can the last few days.

I want to find a solution for protecting the back of the drivers. I have temporarily used grill cloth to cover the backs. Sound is a little muffled so will work on quick remove back covers with velcro so for proper listening I can listen with the backs uncovered but for day to day use I will keep the covers on to protect the drivers from being poked, dust etc...

Couple of questions:

For the plate amp (Yung SD300-6 300W) - I wired the positives and negatives of both Left and Right driver to the red and black lead from the Yung plate amp (model is the 400. Assume this is correct. I would be interested to know what position people using this amp have the cross-over and the level. The scale of the crossover starts at 40hz and goes to 200hz but not sure where the 90hz position is. I have it just before the half way point. The level I have at the first dot above minimum. I have neighbours downstairs

.

Also, what is the maximum space between the speakers in feet and what about the level of toe in. Any recommendations from listening experience would be great.

Finally and most importantly, the Hestia OBs sound have also achieved WAF

Newbie

matevana · « **Reply #266 on:** 6 Jan 2015, 10:49 pm »

Hey Newbie,

In all the discussion over the wiring, I neglected to compliment you on your build. I really like the appearance as well as your interpretation of the design. Nicely done!

I no longer own the original configuration so I cant comment on the Yung's settings. Generally 1M or greater from any room boundary is appropriate, but people have placed them closer as necessary. I had them toe'd-in so they crossed about 1-2 feet ahead of the listening position. I found that provided the best imaging, if memory serves.

Regarding the tweets, if the VC's were blown the distortion would be obvious. It is likely they came out of it unscathed!

Ed

bear-hifi · « **Reply #267 on:** 24 Feb 2015, 01:44 pm »

Hello

I'm going to finely start on this project but I need a pair of tweeters. Would the XT19 be worth the extra $ over the D19? I have all the other drivers and the inductors (.70mh) for using the XT19 however if I buy the D19 I will need buy a pair of 1.40mh...

Thanks
Frank

brad944911 · « **Reply #268 on:** 24 Feb 2015, 03:31 pm »

Bear,
I wish I could help with a direct comparison, but I've only used the XT-19. I'm quite happy with it all around. I will caveat that you MAY want to add a PAD inline. I was contemplating it as the tweet will inherently be a bit louder since it's 4 ohm and getting more power. I eventually went fully active with DSP...I know it's cheating, but what a difference it makes to be able to tailor everything to your surroundings and taste...NOT that Ed's taste is bad. I don't want to get a beat down from the maestro here!!

For those interested, I completed a little modding on my version of the Hestias this weekend. I did a LOT of soul searching and researching, but eventually removed the dustcaps, built and inserted a phase plug in the pole piece. I know that you usually hear an improvement proportional to the amount of work invested, but I gotta say the plugs, pole extensions, whatever, really cleared up the overall sound of the speakers and I now am crossing them from 105 Hz to 4KHz with LR4 slopes and using a low Q, 10 dB notch at 575Hz to get rid of the inherent "honk" or beaming from the 10's. The XT19's are crossed at 1.6K and blend nicely. I just did this this weekend and am still tinkering. I'll stick up a pic when I can.
Once again, thanks to all you guys and especially Ed for putting this together. I love this stuff!!!
Brad

matevana · « **Reply #269 on:** 24 Feb 2015, 10:48 pm »

Frank,

I'd be tempted to try a single high quality cap (1.5 - 2.0 uf) with the XT-19 and omit the choke. Where tweets are concerned, inductors can be

. Go with a Mundorf Supreme or something comparable. As Brad mentions, you may need to level match. The XT-19 used in the Hestia V Dome sounds great.

newbie7800 · « **Reply #270 on:** 3 Mar 2015, 12:02 pm »

Hi Hestia OBers

Couple of comments.

Brad - would you mind explaining how you carried out the dust cap mod. Just on the MCMs was it? Would welcome details. Would also love to understand how you implemented the active cross over.

All - I am having a problem with vibration. I built the taller version (as did SJHOMEY). The baffle is ply and thickness is as per Matevana's original design. Any clever tips to reduce. I am also getting little volume control from the bass plate amp. It just is too powerful...

BR

newbie

matevana · « **Reply #271 on:** 3 Mar 2015, 12:47 pm »

Newbie,

If you look at the original proportions of the Hestia design, you can see that the baffle does not extend out more than 25% of the drivers diameter at any point. The design relied (in part) on the rigidity of the driver's frames to help prevent baffle flex. That being said, two things come to mind which may help with the modifications you have made. The first involves increasing rigidity; the second vibration damping.

Aside from increasing baffle thickness, some have had good luck by coupling rigid "C" or "L" channel down the back of the baffle. (Think industrial wide shelving standards). Try to run the C-channel on the diagonal to some extent (avoid running completely parallel to the baffle edge) as this will counter a greater degree of lateral flex.

Still others have had luck eliminating buzz by damping the backs of their existing baffles. There are recipes for DIY damping compounds online that contain tile mastic and granulated rubber (like rubber mulch but finer). The compound is troweled onto the back of the baffle with a v-notch trowel and allowed to dry. Some have used alternating layers of the DIY compound along with roofing felt to create a sandwich effect. Haven't tried this with any baffle (haven't needed to) but the concept is interesting.

brad944911 · « **Reply #272 on:** 3 Mar 2015, 06:23 pm »

Hey Newbie,
My solution was, as Ed said, double panel thickness; 1-1/2" thick when finished. The baffle sides also widen as you get closer to the floor. You may want to try a "T" type brace down the back like in the Jamo & Linkwitz speakers. I'll likely do this soon as I'm getting some vibration from the sub (which is attached) in the upper sections.
The dustcap mod was a little spooky and you will likely tear some of the top fibers leaving a ring where the cap was. No real harm though. If that doesn't bother you, then what I did was cut an "X" in the face of the cap from the center out to the edges giving you 4 "pieces of dustcap pie". Then gently and slightly lift the corners of the area glued to the cone and SLOWLY work the X-acto knife around the circumference cutting as closely as possible to the cone. I built the "phase plugs" from discs of wood cut using a 1-3/4" hole saw for the insert in the pole vent and a 2-1/8" for the remaining 3 discs. I then glued them together, ran a 1/4"x4" bolt through the pilot hole, squeezed it all together with a nut and formed the final point rotating against an angled table saw blade. This will make most shop class instructors cringe, so be safe!
The pole piece vent is EXACTLY 1-1/2" in diameter, so a dowel cut to 3/4" deep is also viable.
That was a couple of weeks ago and now something else...still using the (4) MCM 10's but now using (4) Vifa OT19NC00-04 3/4" Fabric Dome Tweeters per speaker in a coaxial design. I attached a pic if you're interested. I prefer this set-up personally and am still tinkering. What this brings to the table is better off axis response and broader soundstage with great imaging. BTW, I listen primarily to music and even watch movies in 2.0.
As for the active crossovers and eq'ing, I use 2 Crown CDI-1000 amps with DSP; one for mids one for highs and a Behringer iNuke 1000 DSP for subs. The Behringer needs a fan mod right away, but for $200 ya can't beat it. I am finding that these open baffles REALLY open up with DSP...there's a little known guy with the initials SL that uses it extensively. It is cheating, but I don't have time or money for the test gear or to buy and store all the LCR components it would take to do a passive system correctly. If you are asking about cross points and equalization, that's lengthy and I'm still playing around with it. You'll need different values for different environments so there's no substitute for experimenting.
Hope this answers your questions and helps,
Brad

matevana · « **Reply #273 on:** 3 Mar 2015, 06:45 pm »

I think it was AC member PoultryGeist who came up with the idea for using wooden eggs found at craft stores as phase plugs. He put two (or 4) screws in the base and the "plug" was then held in place magnetically by the driver's own magnet, after performing the dustcap-ectomy procedure described above.

brad944911 · « **Reply #274 on:** 3 Mar 2015, 07:40 pm »

Yea, I saw that. I didn't realize he did it on the MCM's...that woulda save me a LOT of fabricating!

matevana · « **Reply #275 on:** 3 Mar 2015, 08:07 pm »

LOL, yeah, you were busy! But you got those nifty point source drivers to show for it.

brad944911 · « **Reply #276 on:** 3 Mar 2015, 08:31 pm »

Indeed! The wife threatened taking the boat out without me...THAT was all it took to simmer down on the speaker hobby

I think at this point that I'm cluttering this thread with all the changes I made to the original Hestia; the only shared component is the MCM 10's. So if anyone else has questions on my set up, PM me or I'll be glad to start a new thread.

Ed, thanks again for doing the legwork to select the drivers and all the design work! Truly a great intro to OB and it was actually you that warned back in December that I'd never be truly done...

Take care guys,
Brad

matevana · « **Reply #277 on:** 3 Mar 2015, 08:53 pm »

Feel free to continue Brad! I no longer own the original Hestia's so if it weren't for people like you there would be little activity here, lol. Besides, seeing the evolution has been fun for me.

newbie7800 · « **Reply #278 on:** 3 Mar 2015, 10:20 pm »

You guys are amazing. Lots of info here. Will digest and come back to you and keep posting Brad. The evolution/tweaks are always interesting

bear-hifi · « **Reply #279 on:** 28 Jun 2015, 04:47 pm »

Finely got my done and I really like them... thank you for all the help!