Latest DIY Speaker and Amp Project

You do seem to have a knack for this sort of thing!
If they sound even half as good as they look, you'll have done well.

:notworthy

 

stunning looks... Fantastic work !!!!

 

Thanks once again chaps. You all have excellent taste

 

Yes all the spraying was done outside on the backyard. So just goes to prove you don't need a perfect setup to get pleasing results. I do have some rather nice spray equipment and products that does make the job easier and certainly more professional looking.

Thanks.

The construction isn't overly complicated, its time consuming but with a little thought, manageable.

Here's more indepth look at the construction:

Construction of the bass/mid enclosures

Building up the start of the bracing:


Almost finished the skeleton of the cabinet:


Finished skeleton:


18mm MDF walls added. 9mm MDF will eventually go over these.


Driver openings cut.


Quick test fit to see if things go together correctly.


A shot showing the acoustic foam wedges that sit in the path of the rear wave.


Lining the midrange enclosure section with 2mm lead sheet:


Line the walls of the cabinet with 2mm bitumen and 10mm acoustic foam as well as stuff the wadding into the bass section.


Shot to show the makeup of the midrange enclosure section. Going from the outmost layer to the innermost you can see first the 9mm and 18mm MDF then the 2mm lead, 2mm bitumen, 10mm acoustic foam and finally the large foam wedges that sit in the path of the rear wave coming from the driver.


Finally a completed mid/bass enclosure.

 

Mid/bass baffle construction

Rear portion of baffle lamination:


Shot showing the front(driver end) and rear baffle laminations:


Gluing the two together:


Front and rear attached:


Making the recess detail. Note the fence used to guide the router along the line.


Using a homemade circle jig to do the half moon.


Sand and trim the corners where the router couldn't reach.


Then test fit


Cutting the facet details in the baffle using a sliding compound mitre saw:


An almost complete baffle. You can clearly see how the laminations are arranged when looking at the facets that have been cut:


Finally all the joints that were showing on the facets are veneered ready for spraying onto. This is a mid/bass baffle completed.

 

Shots of the bare MDF completed cabinet.

 

That is not complicated...

 

It looks more complicated than it is. I think anyone with inclination can do something like this. I'm by no means a skilled craftsman just someone who is passionate about the hobby. I also think the success of any project is absolutely determined by the level of planning/design and the quality of the tools you use. Get those two things right, throw in the passion, and the rest falls into place with time and care.

 

Seriously impressive - top marks Shin

 

With all that bracing, how did you manage to calculate the interior volume?

 

I used CAD to design the enclosures so that made things much easier and quicker. It might have been a big ask to sit down with pen and paper to work it out, especially with my arithmetic.

 

.

 

Great stuff. Just masses of router work eh ! Do you think you would have needed all that bracing if you'd have gone for locking mitres instead of butt joints ?

 

Good question. Definitely yes, locking mitres would be a little stiffer around the joints but wouldn't shift the resonances up in frequency to same extent that closer center to center bracing does.

Something I'd like to try in the future is tensioning panels using threaded rod. I've read reports that this can be combined with subtle bracing and offer excellent results.

 

I didn't think of any of that. Interesting.

 

Hi ShinOBIWAN,

Any idea what it costs RRP for a pair of the model below yours, the Raal 70-10D?

I am "considering" a pair of Raal 70-10D for my KEF R-107? Though apart from justifying th cost of such tweeters, I am concerned about how these may affect voicing, and if the will sit well with the Kef bass and mid drivers?

Apparently my T33B are 93db 4ohm, the Raal is available as 94db 4ohm and can have the same size faceplate as the T33. I will have to modify the crossover though, increase attenuation? Series-parallel with two resistors depending on the T-33 crosover circuit?

So I guess I have to somehow trace the T33 crossover?

 

I *think* they're around £130 each so with shipping from Serbia or Canada your looking at just under £300 a pair.

RAAL has a natural sound, effortless and clarity is amazing. You need a subjectively clean, fast and natural mid to crossover to the RAAL to best effect. I've never heard the KEF's your talking about so can't help there, sorry.

Some work would be need on the crossover for sure. What you really want to find out is where the current crossover and what sort of slopes it uses. This information will give a better insight in the direction to take. Also bare in mind that the RAAL works best crossed above 2.5Khz with 4th order slopes and more like about 3.5Khz with 2nd order. If you need lower then the RAAL 140-15d happily handles 1.5Khz/4th order very well.

 

I have just looked at the Solen Sept 1st 07 price list! 313.20 each? But what currency?

The Kef Reference 107, it has the same head arrangement as the 105.2 and 105.4, a kef b110 type midrange, similar in signature to Spendor BC1 and LS3/5a I guess. That BBC type sound

I'm still digging around for crossover schematics, they have crossovers in the head and bass cab, but I am unsure if there are elements of the HF circuit in both. I may check out Stereophile, they hae a pretty reasonable review of the Kef R-107. I could dig out and look at the old crossovers I have in the loft. Failing that write to Kef.

Depending on cost (at the moment I am scrubbing up an old pair of 105.4) I may end up chasing this after December. The Raal 70-10D is the only model that will fit in the head assembly, as it requires a 95mm to 100mm square face plate with specific mounting holes, I have been told by the gentleman at Raal 4ohm and a custom faceplate is possible, so the only four points to worry about,
Integration with current drivers, will these blend in acousticaly with the current mid and bass?
How difficult the crosover may be (will it be simply a case of increasing attenuation with two resistors serries parralel? to match the T33? Is this just to reduce the 70-10 from 94db to 93db sensitivity?)
And of course the price in £ inc delivery?

 

24db/Octave crossover. Crossover frequencies 160hz and 2.5khz.

They are 20hz - 20khz +-2.5db, so how will the extended responce of the Raal 70-10 affect this?

 

Hey Mike,

Its been a little up and down with the sound. Its started to slowely come together as I find what works and what doesn't. Even small changes leads to quite noticeable changes in the sound so tweaking has been methodical but slow. 3.5way WMTMW isn't particularly easy to tune. I found that using the upper mid for the 200-2500hz range instead of the lower one provided for a more natural sound and shifts the scale of the soundstage to the correct proportions and allows the imaging to more correctly 'float' at a wider range of heights giving some sense of vertical scale as well as further widening the horizontal and depth directions. I was surprised by the difference since the two mids are essentially in identical situations. You'd expect some small difference but the whole sound shifts and snaps in place by the change.

The speakers are extremely free sounding, nothing is strained and all the music is just allowed to pass. You feel like your hearing everything there is to hear. Easily the highlight of the speaker is the treble quality which is uncannily real sounding, cymbals and other sharp transients have perfect pitch, life-like attack and you hear the decay and associated harmonics even amidst complex sounds. Not heard a speaker do HF as convincingly as this.
Midrange is best described as creamy and lucid. Its alive but smooth and non-fatiguing. Its not quite as dynamic as I'd like particularly when you compare the whip crack explosions the ribbon is capable of. But overall its an easy and certainly involving listen. Despite describing them as soft the detail and textures in the sounds are brought across with alarming realism at times, its just they lack a bit of bite.
The bass quality is again slightly soft but I think this adds a natural and forgiving touch. This 'soft' trait is down to the mineral filled polypropylene cones. The extension is quite adequate, giving scale and a great sense of weight and size to larger instruments and even the acoustics of the venue your listening to.

I do still have complaints but these are small and will likely come with further tweaking. One of these is that speaker is quite intolerant of poor recordings and because I have a lot electronic music this will have to be addressed. However feed in q

Frequency response graphs showing individual driver FR's with filtering as well as overall response.



Close up displaying +0.5dB/-1dB accuracy.