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A thread for me to dump stuff into.

post #1 of 47
Thread Starter 
Instead of posting bits scattered throughout this forum I thought it would be better and easier to keep them in one place.

I receive the odd PM every now and again asking about finishing and spraying so I'll keep to that for now and try to help others out with questions should they have any.

Everyone likes videos and a static photo will only tell half the story. So to better illustrate the paint jobs I'm talking about here's a couple of videos I've taken of my current project:

Sparkle effect over baffle(1.7Mb)

High Gloss Finish(3.3Mb)

You'll need the divx codec installed onto your computer. If double clicking the files doesn't work then drag on drop them into your media player. If you don't have divx then I recommend downloading and installing ffdshow.
post #2 of 47
well done Shino! this will be very handy my friend!
post #3 of 47
Exquisite finish,bravo...

What did you use to cut the baffle ? CNC machine?
post #4 of 47
Sorry but the first thing out of my mouth when I saw the pictures was "holy crap". Man I wish I had 1/10 of your skills on this kind of stuff. Very nice indeed.
post #5 of 47
Shinobiwan,

Spectacular job.

How long have you been working on these? Planning, building, etc?
post #6 of 47
Amazing work. Those are stunning. Probably one of the best looking speakers I've seen. I can't wait to see them finished.
post #7 of 47
Just the other day I was wondering about the progress of this project and wanted to ask but didn't want to come across more impatient than the builder. Exquisite work indeed Shino.
post #8 of 47
Wow.

That's probably the best DIY speakers I've ever seen.

Great design and craftmanship.
post #9 of 47
I realize now that my DIY speakers look, well...homemade. I'll be studying your methods before my next build. Great work!
post #10 of 47
yes, they are absolutely stunning.

Funnily enough-don't laugh now- I reckon they look great even in mdf!

What I did want to ask shinobiwan, I've noticed in all pics of your different builds the use of EXTENSIVE bracing!!

Is hat just because of it being a case of 'if you're going to do a job , you may as well do it properly' or is it based on personal experience of the benefits of a well braced box over a less well braced box?

If so, would it be too much to ask you to give a brief account of those experiences?? And of course if it is based on 'hearing' the benefits, could you also give us an insight into whatever 'rule of thumb' you apply in deciding where and how to brace the box.

I'm still learning you see!!

thanks
post #11 of 47
I could go on and on with lengthy words of appreciation but all that I can say right now is that to my eyes, "this is the benchmark of DIY speakers".
Simply, exquisite piece of work showing tremendous amount of patience and passion for the work.
Shinobiwan,
You will have many years of pleasure looking at your accomplishment and I am sure pure listening pleasure too. Kudos
Enjoy.
post #12 of 47
Shinobiwan,
I think that you are an artist...

RayJr
post #13 of 47
Quote:
Originally Posted by Rayjr View Post

Shinobiwan,
I think that you are an artist...

He sure is,those are spectacular.To get that finish has got be extremely time consuming and obviously the results show it was time well spent.
post #14 of 47
Quote:
Originally Posted by Shinobiwan View Post

First off thanks for the kind words.

To answer your question, yes extensive bracing is immediately noticeable. Its not always a large difference depending on what your comparing it to but it is always noticeable over a lesser braced boxed.

The most apparent effect is that the sound moves away from the speakers and associated boxes. This is natural because a greater percentage of the sound energy being radiated into the room is coming from the drive units. The cabinets have less sonic signature, don't add anything objectionable and don't radiate sound into the room alongside the drivers.

One of the reasons why small bookshelves sound great and do the imaging and soundstage thing well is because their cabinet are less resonant than an averagely built floorstander.

Whilst constructing, my rule of thumb is sub-divide the space within an enclosure as if your building a small standmount. So I normally work with a brace-to-brace spacing of no more than 20cm and normally 15cm. If you combine this with a matrix bracing format as well as laminated MDF wall construction of 9mm + 18mm MDF then you end up with something that overcomes many of the resonance issues associated with enclosures. You can go further with this too by adding mass loading to the internal walls.

To illustrate what your dealing with here are some accelerometer tests taken of MDF in various states of bracing and treatment. BTW an accelerometer is a small measuring device that attaches to a surface and measures seismic vibration within the material.

Here is 18mm MDF unbraced:

You can clearly see the rather hefty broad Q resonance at 190hz and the narrower Q of the 600hz one, both of these really extend in time smearing the original signal wreaking havoc on midrange clarity and giving a cupped and nasal character to vocals whilst slowing upper bass making it sound boxy and compressed. The good news is that sub builders have a nice material as there's not a whole lot going on down low.



Now take a look at 18mm MDF with 15cm brace-to-brace spacing:

Notice how the resonances have shifted up in frequency by over an octave or double the frequency. Not only that but the initial level the resonance and the following decay has improved too. This is all natural since your stiffening the whole box structure with the bracing. The trick here is to raise or lower those resonances out of the operating range of the driver that sits in the box. For my project show here these need to moved out past 1.5Khz where the midrange crossed to the tweeter and/or lowered significantly.



Finally take a look at 18mm MDF with the bracing shown above but also with mass loading added by way of using heavy lead sheet attached to all the internal walls. This is what I use in my midrange enclosure:

A remarkable improvement over just 18mm MDF and doesn't get much better than this unless you start looking into using concrete, multi material laminations or composites:




So its clear that for the most important mid frequency range you should take things a step further and build up a multilayer material approach such as I did for this project with 9+18mm MDF, 2mm lead, 2mm bitumen, 10mm acoustic foam. The subjective and objective differences these details make over an untreated and poorly braced cabinet are pretty massive with the latter sounding very much like a loudspeaker reproducing music and the former being much more natural and having realistic timbre and tonality that can fool you into thinking your listing to the real thing at times. Basically every facet of the sound improves to some degree when the box construction is right, there's not such thing as overbuilt here.

Hope this helps.

Shinobiwan,
This information sure helps. When I had my cabinets built by a cabinet maker (a big no no in your books) I had extensive bracing in mind, but he didn't do exactly what I wanted. However, my subs are double layered (3/4" mdf outside and 3/4" ply inside and an additional layer of mdf at the bottom) and reasonably braced. I was worried about resonance and coloration, but interestingly, the subs sound sooo good that they are very identical to the dual JL f113s I had in terms of sonic signature, but with much higher output (headroom) and lower extension.
I think I got away with less than optimal bracing because I am dealing with sub 80Hz material. If I ever end up building mid-bass modules or main speakers, my benchmark for construction is going to be yours .
Thanks for the useful info. It explains why "less than optimal bracing (in my definition)" still worked out well for me
post #15 of 47
wow, that was a better reply than I had any right to hope for!!! Thanks mate.

The attached graphs certainly help visualise what you're talking about.

Can I extrapolate from your answer that the CRITICAL one to get right is the mids?? Somehow I don't think that would be the correct conclusion when I think about it, the stresses on a box are greater (surely) from the woofers, and in most three ways the mids are in the same box as the woofer, hence as your pictures show brace extensively.

Thanks for the effort in the answer, I'm sure that I'm not the only one to appreciate it.

Interesting when you spoke of a laminated MDF wall. The way you have said it seems to imply that a lamination of say 18mm + 10mm will give better results than a solid 28mm. Why would this be so??

I must admit I've thought of this too, but the idea I had was that instead of using something like PVA which would make a rigid lamination, what if we were to use for examples sake only, silicon. Not excessive amounts so that some sort of 'air gap' exists between the layers, but a good bond which unlike the rigid PVA one, there is some sort of internal resilience or give between the two layers. I wondered if that would mean it could actually absorb more energy with the internal friction between the layers than the solid rigid bond which will simply transmit the vibrations to the outer layer unchanged, ie less attenuation of the transmitted energy in the rigid structure than the one with more 'give'.

Does an idea like that have ANY merit I wonder.
post #16 of 47
Stunning work to say the least. Thanks for the extra effort to share your knowledge.
post #17 of 47
The speakers can NEVER be too big!
post #18 of 47
Quote:
Originally Posted by Shinobiwan View Post

Glad you enjoyed the pics.



Oh so true. If your a bloke that rule holds water no matter what the situation

LOL
post #19 of 47
Excellent resource, your posts continue to astound me in terms of text, pictures, descriptions, laymen terms so that most all can understand. I especially liked the accelerometer study you did, very helpful in understanding why you had to go through a lot of work. I look forward to your updates!
post #20 of 47
You should have just gone the whole way and machined these out of solid marble chunks....

Easily the best looking speakers I have ever seen, DIY or otherwise.
post #21 of 47
That spraying video is........ epic!
post #22 of 47
Quote:
Originally Posted by Shinobiwan View Post

Thanks Jonomega but I really cannot take credit for the accelerometer based material resonance testing. That was performed by a talented Dutch chap who occasionally posts on DIYAudio forum.

For the full tests go to his website here (its in Dutch but Babelfish does can make vague sense out of all):

http://www.zelfbouwaudio.nl/index.ph...id=18&Itemid=2

Thanks!
post #23 of 47
Shin, you really need to get yourself a CNC machine, with the amount of cutting you do, it would be your best friend.
post #24 of 47
I thought the Cerwin vegas i saw when I was out of town were big! But that takes the cake. They look like skyscrapers! I prefer ported speakers though.
post #25 of 47
geez shinobiwan

I hope you are as sexy as your gear!! I can just imagine someones reaction if they walked into my room with speakers and amps that look as good as yours, with me in their field of vision uugghhh, doesn't bear thinking about.

Hope the same fate doesn't befall you, (don't disillusion me) but in my minds eye i see an adonis listening to beautiful sound from beautiful gear ha ha ha.
post #26 of 47
Quote:
Originally Posted by Shinobiwan View Post

I know folks around here appreciate power amps so thought this would be interesting.

Its one of three amps that will eventually power the DIY speakers I'm working on. There'll be 10 channel of 300w into 8ohm with each channel dedicated to one of ten drive units spread across the pair of speakers. That's 3kw into 8ohm total just for the fronts.




Very nice amp. Are there guides to making amps on the internet?
post #27 of 47
Top marks all around stunningly well designed and assembled.
post #28 of 47
The old hammer and pliers are priceless,the hammer there when things do not fit.

Now shine that amp to a gloss to match the speakers.
post #29 of 47
Bro Shinobiwan, this speaker is utilising the RAAL. But I think you sold the RAAL right? Care to share what are the issues with it? It seems that it only takes a really high-end customised RAAL to satisfy Romy. I have heard AMTs like ESS, Beyma TPL-150...still lacking what I want.
post #30 of 47
Quote:
Originally Posted by Shinobiwan View Post

Still have RAAL's 140-15d and happy with them. No plans to swap.

My mistake!
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