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Comments
Hah! That was from the bottling day?
Stoopid rain has put a spanner in the finishing works. That's my excuse anyway.
Weelll.... you know, I think it's coming up OK, considering. The flash really highlights where the "bonus" glue is. Probably need to use some sort of sealer on the edges as well next time.
Tomorrow I think I'll go over it with 800 grit and a final swish and be done with it.
Nah! It was a professional job as opposed to my amateur-ish spatters.
That glue has really shown through, eh. X_X At least you can say it's a prototype...
Paint it black :-b
I see a red door and I want to...
Hah
Like most of us, some angles are better than others...
Well, that's it for finishing. Now to finish it! Went and got some speakons yesterday.
Fer chris' sakes John, hurry up!
I think I want one of these behind my HT chairs.
Don't take this the wrong way but that image made me think of this...
And I'm not sure that's a bad thing from a decorating perspective...
Yeah yeah.
Here's a fascinating picture of my first ever Speakon cable! Yes it's short...
Took me all evening. Network cable is cheap but sort of a pita to actually use. Not the speakon's fault, they're actually really easy to use. These things are pretty neat I must say. Unless something goes horribly wrong I'm going to use them all the time now. That's a four pole cable - 2 pairs of wires, one for each driver. They just go in and twist to lock. No more mucking about with trying to get spades in behind an amp, posts that loosen and rotate, banana plugs that come out if you have a thick cable etc etc. Surprising they aren't "audiophile approved" as they don't have big chunks of metal. Blah blah. Best part is the price, even with genuine Neutrik plugs the whole thing was under $20.
Can you tell I'm excited? Nigel if you're reading this download Unibox and give it a try for yourself, it's easy.
More advantages: you can't accidentally short the amp out. You can't accidentally connect your speakers in reverse polarity (unless you make the cable wrong).
Woof woof
Stuff this
Done!
Works
:-b
Sounds good so far, can't test properly because Gopi is watching a TV show. I'm going to draw up the plans for a pair of 12" next. You could make it a fair bit longer than this one. 400x400x1000 would give around 56 liters per driver.
Tinned pears?
Noise
OK, measurements. In red here is the nearfield measurement (one side, the absolute magnitude is not significant, only relative):
This alarmed me at first. The box is a bit on the small side but not that small. Then I realized that the drivers must have a very high voice coil inductance. Simulation (assuming 4 mH) shows the difference (inductance included in purple):
So that's OK then. Here's the good part. The response in blue in the first graph above is the in-room measurement. When I moved the sub to the easiest location for it and the mic to the listening position, that's what I got. Some room gain, some modes in the 30s and 40s.... result -3dB at 25 Hz and nearly flat up to around 80 Hz. Just lucky I guess
No sense in messing with it any further.
What if I use a pair of 8" or 10" drivers? :-b
I only need it as a tune up sub to go behind my rear HT seats.
My current spare 12" Shiva is in a 150 litre (500x 500x 600 external) sealed box, which is way to big dimensionally to use at the rear of my room.
It just gets in the way & is not plugged in. People presume it is connected!
No-one has caught on yet it aint. :-b
Hi Graham, this one is 312x312x586, which is a bit small for a pair of 10's (the one's I've modeled anyway) and it also has some volume in the base. So for 10's I'd make it a bit larger, 800 long would give you almost 28 liters per driver, as would 350x350x636.
With 8's it's a bit all over the shop, depends on the driver. The RSS210HF-4s that Paul Spencer has with say 16 liters per driver... hm, something like 280x280x636 would be about right... bit larger wouldn't hurt. Sealed that is, if you ported them you're back up to large box. The Tangband 6" subs look like little monsters in a ported box, 'course the smaller the driver the less output and/or low end you will get! I'm a bit uncomfortable with the idea of small ported subs for HT though...
Did you have any particular driver/s in mind?
Gee, I'm tempted to get a pair of those 8s and make an under-desk sub... never did manage to get dipoles working there (I guess you'd expect...)
Here's the revised plans, with a start at making a "generic" design. I'm not enclosing the base/plinth in future builds, because it's basically making two boxes i.e. too much work :-|
Easier just to make the box a little bigger. I'm calling it the "Switch Sub" now for reasons that will become apparent later.