Building the NeoDCC as floorstanders

[kravi4ka]

Well, I just cannot hold my breath anymore, decided to post some pictures of the progress I have made so far.
Here are the crossover parts for one speaker waiting to be arranged properly and soldered:

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It's a mixture of Obligatto caps for what's in the direct way of the signal, Clarity SA and Jantzen Crosscaps for the woofer, Alpha core inductors plus some air core Solens and Madisound air core inductors, Mills resistors. For internal wiring I have decided to use some unwound wire from a piece of Kimber 8TC I have left, hope it works out well, I have no access to Cards cable here...

And here is the enclosure, 1 inch MDF with two horizontal braces, looks beautiful. To be honest, I am thinking of using this box as a general rehearsal for a better box, one that would be as crazy as possible. Crazy means front baffle from slate ( I could not believe how well it killed all vibrations from the very powerful and crude motor on my Lenco L74 project) or aluminum and some other experiments. Anyway, I hope to have these ready in a day or two. Wish me some free time guys...

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[JonMarsh]

It's looking good! Yes, finding enough free time is the biggest challenge when doing cabinets from scratch. Please post more pictures as you progress- and if you can, use a secondary rear layer for bracing at least as I did in the original project- otherwise the front panel is a bit "wobbly" with all those holes close together! :W



This one was cut from poplar planking; I'd suggest whatever the best strong hardwood is that you have locally available; now I'm using Maple.

[kravi4ka]

Thanks Jon, will have that in mind!
What do you think about the idea to use unwound wires from the 8TC? At least for the start?

[kravi4ka]

And one more question - the Dayton is a little to the left (right) and the tweeter is close to it, giving a somewhat non symmetrical look-should I worry about it? I used the spacing as per plans...
My crazy idea about the slate front - when using a thick and hard front baffle is it useful that it soaks vibrations or not? Slate is know to have very good damping qualities, its structure is very different from most rocks, something like a million layers in CLD pattern.

[JonMarsh]

If you used the spacing per the plans, that is what the crossover is developed around- the spacing affects the specific baffle diffraction, which in turn affects the on and off axis response- just keep the same overall width and spacing, and you should be OK.

I imagine that slate is not so easy to work with, but the denser and stiffer the material for the front panel is, the better it should be acoustically- that's why I am trying the LBL material in the front panel of the Ardent- now that I have a better source of Maple, I'd probably even try that- but the LBL (laminated bamboo lumber), being a manufactured product, is probably more dimensionally stable with environmental conditions.



This is a reverse view of the top layer of the front panel, showing the LBL and HDF material and the reverse side chamfer.

Here's the glued up front panel nearly complete.



The 8TC cable is fairly good- I have some speaker cables I built up from bulk 8TC- keeping the original geometry is a good idea because of the reduction of inductance. 4TC does that but with half the number of conductors. It's good quality copper, and should work fine for you.

[kravi4ka]

Just a little update...

Two boxes ready, now it's time to put the crossovers together. I will take my time and do it right, might take some time but I will take care of inductor orientation, capacitor and resistor hardwiring.


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And another question for Jon - I can move the tweeter a few millimeters toward or away from the Dayton - is it beneficial to have them spaced as close together or is it better to try and make it as precise to the plans as possible?
TIA again, you guys probably know how it feels to have them almost ready - I need Jedi patience not to rush and finish them tonight...

[JonMarsh]

Moving them a little closer might be even better- I was concerned about having enough "meat" in the front panel that vibration was well under control. Your spacing looks OK from what I can see- downloading one of your larger JPGs.

You should be able to use the online pictures as some guide to a compact layout, though it's not necessary you follow them exactly- consider it a guide. I have a bigger collection of crossover pictures, too, so if you want to PM me your email, I can send you some jpgs.

[kravi4ka]

Thanks Jon,

The pictures on the forum are quite enough, I have wired several speakers and I hope I will do it right.

I forgot to ask about something - I remember that you recommend to have the bottom firing port at a distance to the floor that is at least as the diameter of the port (in my case 3") - is 10 cm OK? I will experiment of course but what is the ideal starting point?

[JonMarsh]

That should be find- you can experiment with a little closer if there's a reason you need it lower, but I'd suggest staying around that.

[kravi4ka]

Today is a great day! The NeoD CCF(loorstanding) sang for the first time and I must tell you how happy I am!

I cannot post the pictures because I left my digital camera at the place that we listened to them, I will do it tomorrow but I simply cannot contain myself and I need to post some SUBJECTIVE comments, this project is the costliest one I have started and I was wondering if they are as good I was expecting and as much as I have invested in time and goods.

Just to give you a perspective of my experience with speakers and speakerbuilding here is what I have owned so far - a bunch of unknown Russian speakers, B&W P4, Dennis Murphy's Usher 2-way and MBOW1 3-way, Ellisaudio 1801b, Jordan J92s in MLTL and VTL, Linkwitz Pluto and I have auditioned extensively almost all Hivi speakers including the F1.1F and F2.2F, I also have a lot of experience with Fostex 206 designs, I still have most of these in storage I have also listened to a lot of Dynaudio speakers which are my favorite so far, also many of those high priced monsters in hi-end shops.

This however is just a list of speakers that usually sound different in different places in the same room not to mention adjacent electronics but I am mentioning them to give you an idea that this is not the first pair I have built and I am not letting my excitement impair my judgment. And there is one other thing that helps me evaluate how a pair of speakers sounds - I spent some time in the HT mastering lab of Doug Sax in Ohai while he was working on Ray Charles' Genius Loves Company that later got a Grammy for mastering, memory always paints stuff in beautiful colors but I have at least an idea of what to search for when I listen to this disc and I do remember the words that describe those details. So let's assume these are not my early DIY days when ignorance was truly bliss and I am not trying to mislead you or get in trouble with your wife

I built the speakers using quality components in important places - Obligatto caps, Clarity Sa and Alpha core, Mills resistors and all is hardwired, internal cabling is unwound wires from Kimber 8TC. The box is 25mm MDF all over with two horizontal braces. Port is exiting on the bottom, body is on silly 10 cm legs.

Speakers were evaluated with a QUAD ss amplifier and EAD DSP7000 Mk3 heavily modified DAC. They replaced Jamo Concert 8 speakers on heavy stands. Room is acoustically treated, you will see the pictures.

Now they are more detailed and the stage they present is wider and deeper than the Jamo but what is very important is that they simply make the music sound very emotionally involving - you can hear the different instruments in a complex classical piece or you hear better the fingers touching the strings and that is not distracting you from the music but letting you feel what it is all about, you hear the irony in Mark Knopfler's voice and the ships sailing through the vast seas in Rimsky-Koraskov's Schecherazade. Jon's intention was a coherent speaker and that is definitely what strikes you as you think about why it is so different to what you are used to - the drivers just complement each other, I usually hear pretty well where the XO is positioned but I was truly happy to be unable to focus on this in the NeoD CCF. Very even tonal balance from top to bottom, very similar to the Concert 8 if that is a reference. This is all with brand new components and drivers, I am a believer of burn in and I do expect them to stretch their muscles in a few days. Will report on that too.

Now not all is roses though - the port needs some playing with, I can hear the box resonate quite heavily and they are very very heavy but yes, these are not design flaws but my mistakes, I am already thinking about a much more rigid construction with a much thicker front panel (1 inch aluminum, slate, CLD, weird crazy composites :twisted: ). I am sure that plying with these construction details, stuffing and so can quite change the way the speaker sounds and interacts with the room, fine tuning always helps of course.

Definitely a new box Jon's style is to be made, this is THE speaker I was hoping for at the current financial situation, only other speaker I would build (again build) is Jon's crazy new project... But that will be possible when I can also have that 25W SET tube amplifier that a friend has and that is definitely a five figure affair...

I apologize if writing about speaker sound is not appropriate and I hope I will not get sued by someone who is disappointed after building them but I as I am not a speaker designer I found subjective comments in context useful before and all I am hoping to do is to encourage someone just like me reading this forum to pull the trigger and make his/her life happy, apologies again if I am crossing the line here.

The only words I find difficult to find are the one to thank enough to Jon - man, you really are an inspiration not only in spkearbuilding but also as a person - the knowledge you share, the attitude, the attention to detail, the patience - I have learned a lot, honestly. A million thanks!

;x(

[Dean100]

The only words I find difficult to find are the one to thank enough to Jon - man, you really are an inspiration not only in spkearbuilding but also as a person - the knowledge you share, the attitude, the attention to detail, the patience - I have learned a lot, honestly. A million thanks!

;x(

Yeah, Jon is very giving of his knowledge and his designs. Just incredible good luck for those of us without the knowledge and skills.

Very glad to hear that you like this design, I have wanted to build these since he first posted the design. Unfortunately, time and finances haven't allowed it.

Look forward to seeing your pictures. :T

[JonMarsh]

I'm very pleased to hear that the NeoD CC is working out for you the way you hoped- it was a bit of experiment for me, but since finishing the first set they are my "daily driver" as we say stateside about cars, and they have been quite useful in judging and selecting other components. I also find that when used as a mains, there very wide vertical dispersion makes a big difference in room power response and sheer usability- I can be lying on the floor reading a book, or standing on my elliptic trainer for a workout, and all is good.

The subjective is very important because there is so much that is missed by conventional measurement techniques, particularly as applied to DIY, not just commercial evaluations. I found mine improved in tonality and musicality with some after some extended burn-in (I think this is mostly a function of capacitor dielectrics), and they also respond well to things like improved speaker cables- I didn't expect as much difference going from Kimber 8TC to Cardas Golden reference, for example.

Enjoy the music, and have fun tweaking them- keep in touch with us about what you try and how you think it works! :T

[kravi4ka]

Here is the pair playing at a friends house, my system is under revision of course...

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Will post some pictures of the innards later and a few comments too.

[Spanky Ham]

kravi4ka,
I don't think anyone has any problem with your review. I think most here will probably appreciate it. I know I do.
I haven't been around that much lately, but I think yours is the most complete build and listening impression that I have seen on the Neos outside of Jon and Thomas. Your background does give a little more weight to your opinion. I hope you enjoy them in their current box and whatever new box you come up with. Will the Neos spring to life a Neo Mod thread? :rofl:

P.S. - How many people have made the Neos?

[JonMarsh]

I know of about a half dozen.... all have been surprised at how good the midrange inner detail and overall neutrality is. :W

After living with them continuously since late 2007, I'm not. :W It's my favorite speaker to date. (of my home brew designs)

[AlanH]

P.S. - How many people have made the Neos?

I recently built one for use as a center channel. Well really I just cut a new baffle because I had a different DIY center channel speaker in the same size box. All I can say is that the NeoD CC was a vast improvement over the other center I had built. The midrange seems very clear so dialogue in movies and TV shows is excellent. Even my wife noticed a difference immediately. I've listened to it a little in a vertical orientation with music and it performs well enough that I'm thinking about building L+R towers like kravi4ka's.

This is the first Jon Marsh design I've built, and I'll admit the crossover is daunting compared to the others I've built, but it seems worth it for the level of performance. So thanks Jon!!!

[kravi4ka]

Promised to post some more pictures, here they are, hopefully I will get some criticism for some of the decisions

Here is a shot of the front around the tweeter section, the flash did not make a great job, the camera is an ancient device for sure:

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The tweeter XO board is fixed to the sidewall on the tweeter side

Here are two pictures of the crossover:

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Here is a picture from the inside of the box looking toward the bottom, you can see the bass and mid crossover barely squeezing in the lower chamber, I was planning to put all three there but it was simply impossible, this was probably the scariest moment in the whole build, I thought I would not be able to get them all in the box 8O :

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The port is 15 inches long and I was wondering if it is too long, I was shooting for 40 L volume but it looks much less...

Now the things I am not very happy about - I had only a few pieces of Black Hole 5 left from another project and I placed them on the top of the box, behind the woofers and I had nothing for the sides. Of course I could not wait any longer and now the boxes play their own version of the music together with the drivers :evil: . I had some Acousta stuff too and managed to squeeze about 150 lb in each box between the port and the crossover boards. The tuning is almost right at the moment and if you were wondering why I made those ugly legs here is the reason - their size is 2X3X4 inches - that way I can play with the distance from the port to the floor, as Jon suggested 4 inches works best.

If you guys spot anything please let me know, will be much appreciated.

P.S.Thanks for the post Spanky Ham, actually when I was thinking about posting the comment on how they sound my intention was to be very elaborate but I reduced the description quite a lot, I have heard mediocre speakers absolutely transformed by good upstream components so I was hoping to encourage people but to be objective too, that's why I tried to post all my relevant previous experience with DIY speakers.
Thinking about it, this is the most satisfying DIY build so far, may be 75% of what I expect from a speaker and I know how to get 10% more, a 100% would require many times the current budget ( including ET/Jon's new project but also a dedicated room, amplifier and so on). I sleep VERY happy guys

[kravi4ka]

While I am irritating the neighbors with the speakers playing Massive attack quite loud to break in I am searching the net for possible new box materials :twisted: .

So what do you guys think about thick sheet (3/4 or 1 inch) of aluminum glued onto the 1 inch MDF front I have at the moment?

I found some posts about Corean too but no comment on how it sounds - does anyone have any experience with it? I have a local guy that is miking counter tops and stuff, may be he can make me a front baffle or even a whole new box :roll: I have also BB ply here at hand,HDF, even exotic hardwoods from Africa, I also have some wild dreams about sandwich constructions. Any idea will be much much appreciated before I get too much carried away...

[Bear]

So what do you guys think about thick sheet (3/4 or 1 inch) of aluminum glued onto the 1 inch MDF front I have at the moment?

Expensive. If you are going to go for that thick of aluminum, then skip the MDF. You'll find 0.75" aluminum in that kind of quantity to be prohibitively expensive unless you just want to just go all-out.

Check out the Ardent thread for some discussions of various materials that might be a little less $$.

Bill

[kravi4ka]

Thanks Bill,

Well I live in a country where sometimes thick aluminum is cheaper or at least easier to supply than BB... Plyboo is more than impossible to source here so I will probably go for a thick HDF front made out of several sheets, probably some other materials sandwiched in between. I was wondering about Corian because I found the biggest supplier in the country is located 10 kilometers from my house and I was hoping it is not that expensive but I guess I am mistaken.
One other crazy option is slate that I mentioned before, it has some properties unlike any other rock and was successfully used in making turntables which is also a very challenging task. Here is one example :

http://www.oswaldsmillaudio.com/Products/turntable.html

I have my own project on the Lenco Heaven forum which was frozen till I finish the NeoD CCF so I have some experience with slate and I can confirm it has great vibration reducing qualities, it sure sucked any sound from the very powerful Lenco motor spinning at 1500 rpm, at least I cannot hear anything even using my wife's stethoscope. It is heavy though and working with it is not easy but I am truly amazed by the unoptimized results from the NeoD so I might consider it in the future.

[Hdale85]

Well a floor stander made out of slate is going to be near impossible to move Very heavy!

[kravi4ka]

Well I was thinking about slate for the front baffle :roll:

Feels like I left you with the impression that I have lost my common sense... ops:

[Hdale85]

Just making sure. Even so they would be incredibly front heavy. Possibly more likely to flip on it's face.

[kravi4ka]

You are right, thanks. I just checked aluminum - two sheets for front baffle 20 mm thick will be about 200 USD...Haven't got a quote on Corian yet.

[Bear]

You are right, thanks. I just checked aluminum - two sheets for front baffle 20 mm thick will be about 200 USD...Haven't got a quote on Corian yet.

Depending on your source, finding a single 40mm sheet may not be that much more difficult and/or expensive. However, since most speakers use no more than 46mm of MDF, 40mm of Al would be much, much stiffer. Pretty, though, especially if you get it anodized.

Corian should be less expensive, but a bit more of a hassle to machine than some grades of Aluminum (just get good bits and go slow with Al). Slate would be even more challenging to machine given its propensity to chip and flake.

Others to consider: Baltic Birch Ply, HDF, LBL, etc...

[JonMarsh]

You are right, thanks. I just checked aluminum - two sheets for front baffle 20 mm thick will be about 200 USD...Haven't got a quote on Corian yet.

I've got some Corian for a project a couple of years ago, but never used it. It should work well, but it's hard to source- they keep it restricted to licensed contractors in the US who "normally" won't sell pieces of it. I'm still up in the air what to do with the pieces I have.

[Coconutout]

omg those crossovers... they look like a pile of jewels. talk about no cost-objection builds. you make my jaws drop, sir. i will dream about knocking on your door with my favorite cd and a roll of doobie hoping that you won't mind either. haha silly dream. you make my rbr build look like a child's play. have a good day ,sir

[CraigJ]

I found some posts about Corean too but no comment on how it sounds - does anyone have any experience with it?

I made my Isiris Jrs. out of Corian and four layers of laminated HDF. From what I can tell, "it" doesn't sound, and the baffle is very stable at 1.5 inches. I was luck enough to find a friend who was throwing away a very large kitchen counter/island, so I recycled his old kitchen. IMHO, six layers of 1/4" HDF will give you similar results.

Have fun and good luck.

Craig

[kravi4ka]

omg those crossovers... they look like a pile of jewels. talk about no cost-objection builds. you make my jaws drop, sir. i will dream about knocking on your door with my favorite cd and a roll of doobie hoping that you won't mind either. haha silly dream. you make my rbr build look like a child's play. have a good day ,sir

Hi Coconut,

Well I was feeling the very same way a week ago but I was going to knock on Jon's door .

I wish all of you could come and have a listen, it is so difficult to describe the sound of speakers... The Neo D CCF is becoming sweeter everyday!
And your RBR build is a labor of love too, that is for sure, it always shows. If you happen to be close to Bulgaria you are welcome anytime as is everyone else :T

[kravi4ka]

I made my Isiris Jrs. out of Corian and four layers of laminated HDF. From what I can tell, "it" doesn't sound, and the baffle is very stable at 1.5 inches. I was luck enough to find a friend who was throwing away a very large kitchen counter/island, so I recycled his old kitchen. IMHO, six layers of 1/4" HDF will give you similar results.

Have fun and good luck.

Craig

Thanks a lot Craig, you help me cool off my head, I will take time and make it as best as possible, I need to make some sober decisions and you advice on HDF is great, I remember when I wanted to build the M8ta I bought a large piece, hopefully it has not bent in the meantime in my father's garage... Thanks for the answers guys, much much appreciated!

[TacoD]

I once did a speaker with 10 mm corian with 30 mm mdf backing. Worked out very well, but it was expensive.

I think machine aluminium will cost even more in my country (your 200$ quote sounds very reasonable to me, do your local shops also do the machining?)

[Hdale85]

200 bucks for sheets big enough for 2 baffles is pretty dang good....Makes me think about using aluminum....

[kravi4ka]

Checked the Corian today, was given a quote of 400 USD for two finished baffles with the right holes and stuff, just to be glued to whatever I decide. That's a pretty high price for me It is also 1/2 inch thick. Is that OK(read rigid enough) for a front baffle, say glued to a sheet of BB and a sheet of HDF?

Turns out aluminum will be about the same price after CNC and finishing.
I have the voice in my head whispering HDF/HDF/HDF/HDF ...

[kravi4ka]

Biggest temptation came today - a friend of mine knows the owner of the casting facility that makes the "boxes" for the Everything but the box loudspeakers, for those unfamiliar with the company here is a link:

http://www.everything-but-the-box.com/

What a coincidence - I have in a super modern casting facility my town that is already making loudspeaker boxes! 8O 8O 8O

I spent an hour talking to this guy who is also professor at our Technical University and teaches casting of metals and his advice was not to use the aluminum sheets I found earlier in my quest because the alloy that is used to produce it gave worse results after measuring of resonances and subjective listening compared to the alloy they use to cast EBTB boxes. The EBTB box is made of AlSi3 alloy and is supposedly dead as a speaker box material, only problem is the size of my box (I asked about ringing and he asked me if I have seen a bell made from aluminum ) It sure has a resonance frequency but it should be easier to handle as it is higher up in the range . I will probably just make the front baffle from it and I am thinking about going for 20 mm. Now I just need to find the money,I guess I have to part with something....

If any of you guys find this a bad idea please let me know before I apply for mortgage on the house :roll:

[kravi4ka]

Hi Jon,

I have a question to you - the speakers are breaking in beautifully but I am getting the feeling that the tweeters are a just a tad too soft for my room. Is there a way to bring their level up a bit without messing up the crossover?

P.S. Apologies to everyone that does not like how many thoughts about the new boxes I share, my intention was not to turn the thread into a blog or something, I was just feeling in deep water... ops:

[JonMarsh]

The gated 1 meter measurement of the final design looks like this on axis.




Your room placement is a bit closer to the back wall than I would usually recommend. Mine are about 1 meter from the wall to the back of the enclosure, and 1.66 meter to the side wall (golden mean ratios).


Your situation will lift the bass region more, which will subjectively make you want to increase the treble to counter act. That won't necessarily result in flat, though.

The crossover uses a conventional LPAD configuration.




In this case, it's characteristic impedance is set for the 6 ohm tweeter. You can use an online LPAD calculator to calculate new resistor values for R12 and R13 to adjust the treble output up or down. The impedance load back to the filter always should stay at 6 ohms total.

[kravi4ka]

Thanks Jon,

I had not posted a picture from my actual setup so here is one, the first one was from a friend's house just placed there for the picture:

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My room is on the small side and I had to place them 1m from the back wall and 60 cm away from the side wall, at least that is what subjectively worked best. I tried several types of amplifiers as you can see - powerful tube, class D, SS and the results are simply great. Will work with the L-pad calculator.

[kravi4ka]

Now that all eyes are on the SDX-2 (I wake up and go to sleep with the thread too), I decided to post an update on my life with the NeoD CC. I haven't made any progress with the new box but I had some time to play with the resistors on the tweeter section of the XO.

I was complaining that I would like to get just a little more sparkle from the tweeter and Jon suggested a few values to try. First was the original configuration with 1.2 Ohm series and 22 Ohm in parallel and it was definitely a little too much so I think the right balance will be right in the middle - next to try is 1.5/18 , probably in the next few days.

There is something else I'd like to mention though - having tried a few types of resistors and being a fan of Mills MRA12 I must warn that my experience is that these are a little soft compared to sand cast ones and MOs. I haven't tried Mundorf or Eagles unfortunately so I cannot comment on them but in my previous builds it was much cheaper to have a bunch of sand cast ones to tune the level of the tweeter and when I had settled for a combination I would order the same MRA12 values. The result is always different - sound is darker and softer but detailed at the same time, it just takes time to adjust and sometimes I just adjust the value by 0.5 Ohms. So keep that in mind guys, sometimes it is worth playing with components from different manufacturers to adapt the speaker to your taste,there is a difference.

[Doug Fraser]

kravi4ka:

Please post where you end up with the values for resistors R12 and R13.

I would like to experiment with the tweeters slightly more forward.

Regards,
Doug

[kravi4ka]

Hi Doug,

It will take a while before I settle for a certain value because I have many thing to try also - cables, amplifiers, DACs and so on. But here is what I think about it at the moment.

The highs are there but I am missing the frequencies above say 10kHz, the ones that give the decay to cymbals and bells. You can hear them but I am losing the sense that they are floating in the air, it somehow simplifies the way they sound. I raised the level of the tweeter (R12/R13 = 1.25/22 Ohms) and I got quite a lot of energy lower, it subjectively gave a fantastic transparency to vocals and instruments but still there is that lack of vibrations on Zildjians that makes them Zildjians and not cans... Even my Linkwitz Plutos that are using the AURA NSW2-326-8A which rolls off pretty quickly after 10kHz sound more spacious and with greater detail in the range.

The speakers are very different to what I have had so far - the midrange is simply stunning, this has been confirmed even by SET and Fostex 206 fans, the instruments are separated in a way I haven't heard anywhere and the speaker is very coherent, Jon was right that all drivers are beautifully integrated and you cannot tell where the sound is coming from. But it feels that this is a center channel trying to reproduce the whole range and I am missing some musical info out of the range of the Dayton.
Now I am familiar with the abilities of the Hivi and it is a great driver so I assume it is the XO that is restraining it's output but tuning the box with damping materials and cabinet resonances can take care of some of that, I need to spend a little more time with the Vifa in a different speaker to hear what it is capable of, it might be that it is shut in although looking at its measurements that is not very likely...
To sum it up I am still very happy with this speaker, it does some things in a truly amazing manner that more than compensates for what is lacking, if only we can make the tweeter sing a little more. I am hoping that Jon might give us some ideas after RMAF, he has a more important task at the moment for sure but his ideas would be very much appreciated.

So please try the 1.5/18 Ohm combination, this is the right value for me at the moment and a good staring point to fine tune the beast, may be next thing to try is lower the Dayton output somehow... Part of the reason I chose to build the NeoDccF is that I have been very interested in the Duelund approach and I was prepared that there might be some work to be done, I am still trying to understand what I can play with without destroying the beauty of the sound. Please let me know if you are getting similar results, may be the components I am suing interfere in a way... :roll:

[kravi4ka]

Removed some of the Acoustastuff and put in some BlackHole5, now there is the lower midrange I was hoping for... I guess we should have a separate thread on how you guys TIY (tune it yourself) 8O

[JonMarsh]

Some cautionary thoughts & suggestions

I applaud any and everyone tuning their built up NeoD derived system as they please! I do have a few thoughts and suggestions, perhaps cautions to suggest.


As originally designed with a Duelund type crossover, the tweeter covers a fairly wide range of overlap with the midrange and midwoofer, together being responsible for several dB of overlap output at the center frequency of the design (~1500 Hz).

I know what you mean regarding that zildjian cymbal sound, having played in bands for money from the time I was 14 to 24 as a major part of my income, and occasionally afterwards. I do get that "sound" on my existing NeoD build, which, if you recall the frequency response plots, (not made with an ECM8000 or similar microphone, but an Aco Pacific 7012 calibrated to 40 kHz), is quite extended, though of course, for a 1" dome, with the usual off axis limitations. The biggest factors in arriving at that sound over the last year in increasing order of importance have been tweeter cap selection, cables (interconnect and speaker), power amplifier, and DAC.

While I wouldn't discourage you from experimenting with the tweeter level, I'd strongly encourage you to look into these other areas if possible. In particular, the program source equipment is vital. A speaker cannot reproduce what is isn't fed from the system. I'm not trying to make any absolute judgements, just some suggestions about what to investigate based on my own experience. Nothing in the system makes things "good"; good components only keep from taking good things away...

And of course, there's the obvious point that there is a market for Raal ribbons because of what they do even in comparison to a high quality dome with very low overall HD, including high order HD. But that would be a story for another day.

Regards,

Jon

[kravi4ka]

Hi Jon,

Thanks for taking the time to respond! First let me say that I am sure the design is OK, probably I was looking for a quick and dirty improvement in highs with that resistor change ops:

Now to the source - I am using a DVD player to feed SPDIF signal to an Audio Synthesis Dax-2 DAC which is one of the better DACs I have had in my system ( having had EAD DSP7000 Mk3, Twisted Pear Buffalo DAC, Nelson Pas D1V3 clone just to name a few) and it is also fitted with a pair of PCM63-Y grade chips that significantly improved resolution too so I think I have covered the front end quite acceptably. Here is a picture of the innards, it also got several very favorable reviews from magazines, if that matters:

Image not available

Signal goes to a pair of Stevens&Billington TVC transformers via some Harmonic Technology ProSilway interconnects, very transparent too.
As power amp I have used several types - both SS and PP tube, speaker cables are Kimber 8TC and Furutechs. This combination works great with the Plutos, a pair of Jordan JX92s and Modula MTs that I built for a friend and I am pretty sure the problem is not there, having plenty of resolution. I specifically took the Modulas home to compare the two regarding tweeter level, the Modula is one great speaker BTW.

Now back to the NeoD - I used Obbligato caps for the signal path, weird thing is that the cap in front of the Dayton is Obbligato too, no problem with transparency there... I haven't used them before but they have very good reputation and are matched, will definitely try something else too. Can you please have a look at the tweeter section, just in case something wrong shows up and I haven't seen it, it is the lowest board on the picture:

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Thinking about it, I have a pair of Mundorf Silver/Golds 0.15 uF that I can try as a bypass cap on the tweeter section, which one should I try it on first - the 6.8 or the 35 value( being made of one 33 plus one 2.2 uF caps)?

[Doug Fraser]

kravi4ka:

I absolutly agree with your comments the the `midrange is simply stunning`.

I have not experience the same issues at the low end that you have. I used .75 inch sonic barrier with no stuffing and I find the low range very very good. Mind you, I have also tuned the cabinet differently.

Given your comments that increasing the energy to the tweeter also effects the lower end of the tweeter response (which makes sense) I am going to try a different approach. I have a DEQ 2496 equalizer that I am going to play with.

I will go back and review the measured freqency response that Jon mentioned and then try to introduce a shelving filter for the upper frequencies.

Unfortunatley I am on biz travel for the next 2 weeks so there will be a bit of delay until I report the results.

Regards,
Doug

[Doug Fraser]

I have now connected a DEQ 2496 equalizer into the play back path with the NeoD CC's.

I wanted to make the cymbals sizzle just a bit more.

Everything else is perfect!

I first looked at the freq response of a cymbal. Boy was I surprised! Cymbals can produce frequencies from less 100Hz to well over 20 kHz. So where to start?



I then looked at the driver freq response that Jon posted.



I had really not paid much attention to it but quickly realized that between 2k Hz an 5k Hz duty is shared between the mid (RS52) and the tweeter (D26NC55). So I figured I would start with shelf filter with 2 db gain, 6db per octave slope at 5K Hz - after all, I thought tweeters reproduce the sizzle in cymbals. Well this didn't really add what I was looking for.

So the experimenting started.

The sizzle I was looking for seemed to start around 3k Hz. The issue I ran into was that a shelf filter at 3 kHz also starts to make other sounds a bit too bright.

So after a couple of evenings, many different tracks I ended up with the following:

2 high pass shelf filters
1) 1.5 dB gain, 6 dB per octave @ 3169 Hz
2) 2.0 dB gain, 6 dB per octave @ 5140 Hz

The beauty of the DEQ 2496 is that one can do direct A-B comparisons between two settings.

This is only a first past. I can see many many more hours fine tuning. At this point however I am very very impressed with the sound. Beats my older B&W 802's hands down.

Doug