Have your say & ask the experts

Firstly. Please don't get AE annoyed and this thread locked. It's not productive.


Secondly. The results:

On the cryo question.
If there's a difference my young ears cannot detect it on either solid state or tube.


Secondly, I've made some very nice cables. The difference is most apparent on vinyl. Much more high end detail.



The next order or business is my new experiment.

Whenever I buy something I always think "can I do this better?" To that end I am constructing my first (serious) speakers. The purpose of this experiment is to pit DIY speakers against my Totems in a strict 25% of Cost environment. That is to say, my DIY's will not exceed 25% the cost of my Rainmakers. Now I know this is highly subjective and there is likely psychological biasing because I'll have made the competitors myself. But it's an interesting experiment.

Here are the parts:
A lot of MDF.
2 6.5inch Peerless drivers, (made in Denmark models, not the chinese rubbish)
2 Peerless Textile Dome Tweeters (same)
Construction Glue and Caulk
Screws
A handful of Capacitors
A handful of Inductors
Four Resistors
I had to buy a router
Paint
Primer
Varnish
PVC pipe
Rear connectors
Some cable


Anyway, pics so far are here. Also, I will reiterate: DONT GET MY THREAD LOCKED. Thanks. Hope you guys enjoy my compare-as-I-dare exploits.

Thats the most up to date enclosure photo I've got. Will be drastic progress by monday.

Just for fun here's my setup with my spanking new tube amp...

Good stuff Ray. Thoroughly enjoy reading about your exploits!

[quote user="igglebert"]Good stuff Ray. Thoroughly enjoy reading about your exploits![/quote]

 

Great stuff. Do you use Thiele-Small parameters to determine enclosure size or is this a change-as-you-go along project with the speakers? (Not a trick question or criticism in any way)

[quote user="drummerman"]

[quote user="igglebert"]Good stuff Ray. Thoroughly enjoy reading about your exploits![/quote]

Great stuff. Do you use Thiele-Small parameters to determine enclosure size or is this a change-as-you-go along project with the speakers? (Not a trick question or criticism in any way)

[/quote]

 

Very good question! I use the TS parameters, I input them into a nifty piece of software called winisd which calculates optimum enclosure dimensions. Now you may notice that my enclosure is teh huge for a wee 6.5 driver. But I'm following the optimum path (speaker manufacturers don't do this as it results in ugly/enormous boxes). This way I'm expecting bass performance down to... well have a look!

Nice. Where do you roll the bass unit off and at what frequency does the tweeter come in? Also  what kind of a crossover are you planning to use? I believe some designers/manufacturers dont utilize all the lower frequencies because of the crucial midrange the (usually) same driver has to cover.  Dont worry about answering now if you plan to do this later when you're actually completed the project. Are you going to veneer the enclosurers or is it just a test project?

Fantastic - I wish we could get more of this in mainstream :)

Very interesting!

Does your software give you phase analysis as well?

[quote user="Anton90125"]

Very interesting!

Does your software give you phase analysis as well?

[/quote]First of. I'm using a 3rd order (paralell) butterworth crossover with a zobel on the woofer. As for the roll off, I'm going with 4000z crossover, (the tweeter and woofer are probably going to overlap a couple 100Hz because of my off-the-shelf crossover parts).


I'll attach a pic of my ugly crossover at the bottom here.
I'm not going to veneer, I hate doing it and don't love the result, instead I plan on a heavily glossed solid colour, perhaps two-tone. Not sure yet.


Phase plot is:

,

This is the enclosure latest. Notice the smaller tweeter box on top.




And here is one sloppy crossover/zoble network.

Although Midrange is a concern I have to admit. The 6.5's are "full-range" drivers, my theory is that they'll function up to 4000Hz in this large enclosure, however the proof of the pudding will be in the eating.
If I encounter a "gap" in the sound upon testing I'll experiment with decreasing the enclosure size (using blocks of wood), this should allow me to sacrifice the low-end for midrange.

Interesting. I am no speaker designer and know much less about them than you but why did you choose your particular xover (3rd order B/W)? As I understand it, it is normally used for d'appolito applications ie. mid tweeter designs? 

[quote user="raypalmer"]Although Midrange is a concern I have to admit. The 6.5's are "full-range" drivers, my theory is that they'll function up to 4000Hz in this large enclosure, however the proof of the pudding will be in the eating.
If I encounter a "gap" in the sound upon testing I'll experiment with decreasing the enclosure size (using blocks of wood), this should allow me to sacrifice the low-end for midrange.[/quote]

 

Understand. I think tweeters/mid woofers can overlap by up to 1000hz without serious implications but it'll be interesting to hear what you're going to do. I'm sure your are aware that mid/woofers break up resonances are usually around the 3.5 -4khz zone so you might have to xover before that to avoid nasty breakup peaks around that frequency. Depending on your tweeter that should'nt be a problem. Lovely stuff and respect.

[quote user="drummerman"]

Interesting. I am no speaker designer and know much less about them than you but why did you choose your particular xover (3rd order B/W)? As I understand it, it is normally used for d'appolito applications ie. mid tweeter designs? 

[/quote]My reading on the topic suggested a straight crossover without notch-filters and other more involved circuitry was the butterworth curve. That said I was more influenced by the butterworth curve itself, the maximum possible flat response seemed like a good idea.



As for the breakup, I'm concerned to be sure, if I have to I suppose a replacement crossover will have to be implemented. I wish I had software that allowed for circuitry to be entered into the equation, but that stuff doesn't come cheap.

I need input. I can't decide on how to finish these mamas. If I want to veneer I need to do it now...

I don't want to veneer the top as the tweeter enclosure would make that fiddly and a pain. So I'll just make that top bit black (along with the back). Now, the question is:
Veneer the front and sides?

Or

Veneer the sides only and make the front black to match the top.

Or

Gloss colour coat the whole thing.


Please give your opinion and be it veneer what type, or gloss what colour.

I hate to pick the option you don't fancy, bu veneer them. You'll be pleased you did when you have them placed in your room...

A blank canvas – the possibilities are endless. Spin them while throwing paint at them Damian Hurst style?
Cover them with photos of your favourite artists and bands?
Attach silver discs so they look like Daleks? (er.. maybe not, look at what they did to Selfridges in Birmingham)
Veneering is tricky to do right and why make everything look like wood? Paint is so yesterday.