The Genesis Cabinets

[JimGore]

Hi Shaun,

If you have some time during the week (evenings) or over the weekend, bring your drivers to my place & I will measure the parameters for you.  That's the safest because it takes the guesswork out of the equation.

I have used the CA18RLY in about 40 liters before and it worked fine, but that's years ago.  I wonder whether there were 2 versions of this driver?  Seas is usually very good with the T/S parameters 

Cheers,
Ian.

[Abu]

OK, lemme go back to my notes and see. But like I said before, 44L is just too much for that woofer. Maybe Ian can jump in here as well"?

Any luck finding those plans? I went around to ian's place and they measure close to the documented specs. winisd still confirms a 40 or even 50 litre enclosure so I think im going to make some floorstanders

[GearSlave]

Any luck finding those plans? I went around to ian's place and they measure close to the documented specs. winisd still confirms a 40 or even 50 litre enclosure so I think im going to make some floorstanders

I can't seem to find my original measurements, but here's a thread when I was still learning this stuff. Granted, I was still wet behind the ears then, but based on those results and how other designers used this driver I figured the 40 odd litres were too much. What's the feedback you got from Ian? If he says 40L is ok rather listen to him 

http://www.avforums.co.za/index.php/topic,700.msg6311.html#msg6311

[JimGore]

I loosened the suspension on the driver with a good & strong 30Hz signal for some time, after which the driver was allowed to cool down, and then we did the measurements.

The driver can definitely work in a smaller enclosure, but 40 liters seems to be a happy medium between all the factors.  The driver can definitely work in a smaller enclosure if needed!

I am seriously wondering whether or not there were 2 versions of this driver?  Why else the two sets of parameters, etc???

Ian.

[Abu]

So I was messing around with my design in winisd and checking out the different graphs when I stumbled upon this Max Power Graph :



Does this mean it's loosing power between 50 & 60 hz? Changing the box to 26l or upping the tuning freq to 48 Hz removed the dip.
Is this maybe what you were talking about GearSlave?

[NoSnipeLimit]

Maximum power is a graph showing what the maximum power is that you can input, while having linear excursion.  If for instance you input at signal input (i'm guessing) 80w you will see in the excursion graph that the area betweeen 48hz and 62hz is over the excursion line.  This is why the graph looks like this.

Not really a big issue unless you plan on running it at maximum excursion/power. 

[Abu]

Ahhh..OK.

Thanks for the calrification... not at all what I thought it was.

[Abu]

Seeing as this is my 1st build I'm thinking of doing a trial run with some chipboard I have lying around 1st.

Will it sound OK or will there be a night and day difference between it and the final MDF constructed product?


Thanks for indulging me in this so far 

[GearSlave]

Not really a big issue unless you plan on running it at maximum excursion/power.

Well, bear in mind that -all things being equal - a smaller enclosure will give you better power handling. Power Handling also one of the factors you need to consider when specifying the volume of an enclosure. Based on the data above, it seems reasonable to make the enclosure smaller to make sure you don't run out of steam in high dynamic passages (80W not really being a lot of power in the 50Hz region to begin with).

Seeing as this is my 1st build I'm thinking of doing a trial run with some chipboard I have lying around 1st.

Will it sound OK or will there be a night and day difference between it and the final MDF constructed product?

That's actually a very good idea and it should be good enough for you to gauge the correct volume size. Aim for around 40L and then you can chuck blocks of wood in to take up volume

[Abu]

Holy cow... here's a design with these Seas CA18RLY drivers made for (if i calculate correctly using the internal dimensions) 50 litres?!??

http://areteaudio.wordpress.com/2011/04/20/k-series/

This site has loads of graphs detailing their performance that I have no clue what they mean... especially the waterfall plot

Google time

[Abu]

I've started messing about with a small 16 litre cabinet using some chipboard offcuts as a warm-up for the main event. I have made myself a jasper jig out of perspex and have routered the main driver quite successfully, but the tweeter is so small my jig can't do it. The tweeter diameter is 104 but the smallest my jig can go is a radius of 60 due to base being in the way.

How'd you guys do your tweeters?

[Atjan]

Unfortunately 104 is the outside diameter in all likelihood. I had to go down to about 85mm dia or so. I had to change the direction the jig sat in from along the length of the router foot to along the width and even so had to sink the screw into the jig so it could sit under the foot for the smallest hole. Good luck, this was my least favourite part of the build. Not only was it difficult and nerve wrecking but also extremely dusty when done on MDF. I suggest you sort the extraction out as well....

[Abu]

Extraction??  what extraction ??   

* Abu holds his breath and sweeps some more   

So i think I had an epiphany in the shower this morning. To fasten my jig to the baffle I have a small nail that i put through the jig into the wood from the top. I'm thinking I need to rather have a little stud at the bottom, and then drill a hole in the baffle where I want the stud to go in and pivot. That way I can get underneath the base.

Make sense?

[GearSlave]

I agree with Atjan - doing tweeter cutouts suck.

Just some advice - don't try and do the actual tweeter cutout with a router. I went and bought an 80 odd mm hole saw to do this.

[Abu]

My tweeter needs to be 52mm and 46mm. Does that mean you have to buy a new holesaw for each new tweeter or do you get an adjustable one? Also how would you recess it then?