2 x T30 Slim Build Log

[escapemcp]

These are not crossovers they are filters

I disagree(respectfully), for our purposes, a "crossover" and a "filter" are one and the same.

If they are not I certainly need to be enlightened as to the difference.

I suppose a filter is the frequency based attenuation electronics for a single driver. A crossover is a pair of filters to move from one driver to the next as the frequency in-/decreases. That's my best shot at it! As you say, for our purposes there's not much difference

[miked]

I really like the logos! Do u have a router template? Maybe i missed how you did them?

[escapemcp]

I really like the logos! Do u have a router template? Maybe i missed how you did them?

Yes, I use a router template, but just searched for "speaker logo" on Google. I used something like this:


In reality the final result is much "thinner" than the logo above due to differences between the router bit and the pattern following collar. I'm happy with the results though

[escapemcp]

Here's the template I have used.


You should just be able to see the couple of lines at right angles which mark the centre of the logo (right between the mouth of the driver and the 1st 'sound wave'). I mark out centrelines on panel 7 once the second side is on - although much easier to do BEFORE closing sub I then line them up with the ones on the template and screw the template to panel 7. Set router to the right depth (unsure what this is, as my depth gauge isn't the best, but I'm guessing about 1/2mm) and route away. It takes a while as I only use a 6mm router bit (for higher definition). The only problem comes when it's time to route the driver, as that top edge (closest to the 'magnet') is waay to thin to balance a router on. I usually use a fill in block in the centre of the driver cutout, so that I can route all the bits where the router wouldn't be stable enough on it's own. Of course, remember to do this BEFORE you route out the speaker body or the fill in block is 1/2mm too low... guess how I know that!

[escapemcp]

Handle reinforcement:

1) Cut a 4mmx14mm bit of steel to the right length (16" in my case). Drill holes and countersink.


2) Using a 6mm router bit, route out a hole for the bar to go into:

Note the other hole on the other side of the cab.
If you hit any screws (which are holding the side reinforcements in place), don't worry, cause you are using the shafted 6mm router bit... just drive it through for instant firework display (and partially set fire to cab! )

3) Check that it fits:

That's worth a

4) Screw the bar into place using 15mm screws


5) Check chopped off bit of half round to make handle hold:

DOH! It's too small. Remake.

6) Stand back and admire work. Realize that it may need a few more screws, so remove bar and drill more holes. Refit bar and it should look like this:


The reason why I put the bar through the side, was so that it wouldn't matter which direction the cab was picked up in, it would always be reinforced. I have handles in my cabs in the 2 opposite corners, so if you look side on at 2 people carrying a cab, the cab is like a diamond. If it is lifted with the mouth pointing down, then the bar will brace against the base of the sub. If it is lifted with the mouth facing up (quite difficult, due to high CoG when carried like this) then the bar transfers the load to the side panels (there is NO movement of the bar in the holes - this is ESSENTIAL), although the screws will take some of the load, they aren't really there for that.

It may not be perfect, but this cab never was! It's ANOTHER problem I have had to work around due to the VERY shit wood from which this was created. I reckon with this issue, the extra polyfilla (bondo) & Tuff Cote (Duratex) I have used to get it looking nice and the extra electricity fashioning all the various reinforcements it has easily cost me MORE doing it this way with shit wood than if I had managed to get BB in the first place.

So the next time someone wants to save a few pence by not buying BB, point them in this direction It's been interesting working around the wood's weaknesses and has improved my woodworking skills, but I wouldn't want to build my first cab out of the stuff! Next time though, it's back to trusty 9 even ply non veneer BB. Only a few more nights to go until these are finished now, so 'next time' may well be quite soon. What next?? This shit is worse than crack! Next time Bill, I want a warning on my instructions!

Oh, and hifibob... I'm after you!

[Tom Smit]

I laugh because of the way you describe it all, not because anything else. At least you were able to fix the inadequacies. As you pointed out, it serves as a warning to others.

[escapemcp]

At least you were able to fix the inadequacies. As you pointed out, it serves as a warning to others.

I sincerely hope it does. I decided to continue with the crap wood as a challenge, in order to test my newly gained woodworking skills. If I had used this for my first cab, I don't think I would have ever built a decent cab (some will argue that I still haven't! )

I am looking at one of these pocket hole jigs, but have a quick question. In the instructions for the Kreg mini here, it says that for 1/2" stock the jig must be placed 1/4" (6mm) BEYOND the edge of the workpiece. This would mean that if I was joining 2 bits of wood on the inside of the 90° join, I couldn't position the jig as the wood would be in the way. I am thinking of chopping off the 1/4" off the end of the jig, so that it fits perfectly - does anyone know if it is possible to chop off 1/4" from the end of the jig (it looks like it is just plastic at that point). Or have I got this all wrong and I don't need the 2nd bit of wood in place when I drill the pocket hole?

This is the one I'm on about:


Many thanks (AGAIN! )

Aidan

[Tom Smit]

It looks like you're right. If you cut off the 1/4", then you would have to add a spacer (1/4") when you want to use this tool on 3/4" material, or 1/2" if you are working with 1".

For my use, I would build a jig to so I could hold it in a larger fashion.
Perhaps this is not the most appropriate tool.

[escapemcp]

It looks like you're right. If you cut off the 1/4", then you would have to add a spacer (1/4") when you want to use this tool on 3/4" material, or 1/2" if you are working with 1".

For my use, I would build a jig to so I could hold it in a larger fashion.
Perhaps this is not the most appropriate tool.

I'll cut it to work to the edge with 1/2" stock. All the other measurements that Kreg supply for the vaious thicknesses of wood will just have to have 6mm added onto them. It should be here tomorrow, so I can play and test it.

[escapemcp]

Had a sunny (albeit windy) day today, so managed to get the Otops out in the garden for a quick RTA session to see if I could figure out my 2.5kHz dip. I assumed that the wind wouldn't affect anything up that high - actually measuring it showed that all the wind noise was all in the T30's region, so I figured I could also get a rough and ready RTA (when the kids over the road weren't screaming as they had been all afternoon )

I swapped over the polarity on the woofers, and although there was still a dip at 2.5kHz, it wasn't as pronounced (although still larger than I was expecting). After an RTA though, I had a nice flat response - never seen the graphic looking that flat before Upon checking my wiring I noticed that for some unknown reason, I had the red wire for the tweets going to - and the black to + I don't know how that happened in BOTH cabs!

So after saving my new RTA curve, I took all the kit back into the garage and hooked it up with the woofers back to the correct polarity (+ve to +ve made the woofer move outwards). I immediately noticed the difference (well, differences, all 2500 of them per second!). Some of my tunes had previously sounded particularly 'odd' (as there was no 2.5kHz!), but now they sounded exactly as they should... in fact they sounded better than I remember them As for the subs, since I have V-plated them and joined them in a big stack, I cannot believe the amount of bass I have on tap! I have only given it the full beans for 1 beat as I really don't want to get the neighbours all riled up. I need to find a time when they are all out, so I can maybe go full blast for a whole bar People are not going to know what hit them at the next free party!!

So that's about it now. Rig is working properly. Cabs are finished bar a paint job on the braces of the 24" T30s, but Halfords is out of the yellow spraypaint that I need, so I am waiting on them to get some more in stock.

I'm therefore going to finish up this build thread pretty soon. Firstly here's some finished pics of the rig. I'll try to get a video up tomorrow as my final post in this thread. Thank you for everyone's help. I couldn't have done it without you guys

[sine143]

Had a sunny (albeit windy) day today, so managed to get the Otops out in the garden for a quick RTA session to see if I could figure out my 2.5kHz dip. I assumed that the wind wouldn't affect anything up that high - actually measuring it showed that all the wind noise was all in the T30's region, so I figured I could also get a rough and ready RTA (when the kids over the road weren't screaming as they had been all afternoon )

I swapped over the polarity on the woofers, and although there was still a dip at 2.5kHz, it wasn't as pronounced (although still larger than I was expecting). After an RTA though, I had a nice flat response - never seen the graphic looking that flat before Upon checking my wiring I noticed that for some unknown reason, I had the red wire for the tweets going to - and the black to + I don't know how that happened in BOTH cabs!

So after saving my new RTA curve, I took all the kit back into the garage and hooked it up with the woofers back to the correct polarity (+ve to +ve made the woofer move outwards). I immediately noticed the difference (well, differences, all 2500 of them per second!). Some of my tunes had previously sounded particularly 'odd' (as there was no 2.5kHz!), but now they sounded exactly as they should... in fact they sounded better than I remember them As for the subs, since I have V-plated them and joined them in a big stack, I cannot believe the amount of bass I have on tap! I have only given it the full beans for 1 beat as I really don't want to get the neighbours all riled up. I need to find a time when they are all out, so I can maybe go full blast for a whole bar People are not going to know what hit them at the next free party!!

So that's about it now. Rig is working properly. Cabs are finished bar a paint job on the braces of the 24" T30s, but Halfords is out of the yellow spraypaint that I need, so I am waiting on them to get some more in stock.

I'm therefore going to finish up this build thread pretty soon. Firstly here's some finished pics of the rig. I'll try to get a video up tomorrow as my final post in this thread. Thank you for everyone's help. I couldn't have done it without you guys

rig looks good! you had the red from the tweets going to neg because IITP. suppossed to reverse polarity wire your tweeter arrays to account for distance and filter phase shift.

[88h88]

Yeah the plans say positive to negative but also 'try it the other way, whichever is louder is correct'.

I think I might spend some time with mine to see if I suffer from the same issue.

Awesome work on the setup man, you've come a long way in a relatively short space of time.

[MissileCrisis]

That looks pretty awesome