2 x T30 Slim Build Log

[escapemcp]

yellow
j/k looking good!

I chose yellow as using the favoured BFM purple (which I love btw) will barely show up in the dinginess of a free party. There are quite a few other Black and Yellow touches to my rig (warning tape around tripod legs, silly health and safety signs ("Mind Your Head" & "Dangerous Chemicals")) as well as my r/c plane, so thought I'd adopt it! It will also reflect UV rather well. When I painted it last night, my first thought was "that's bright", but the array will soon be sitting behind a grille (you're going to like how I do that ) and the brace is on the floor, so they need to be bright to show up... this is what I am hoping anyway

Thanks for the comments.. I'll keep the updates coming until I am a 4 sub rig Of course I'll continue to chime in after that

[escapemcp]

Today

Lots of bondo, sanding and duratexing. I managed to get the access cover on and run it up to about 20V and I'm loving the noise I am getting out of these tiny (relatively speaking) subs. I think I'm starting to like the 16" slims more than the 24" ones, just because the losses in sound are more than made up for by the losses in size. Thanks Bill for a great design and everyone else here, for answering my questions as I ask them. No pics today. Will try to shoot a vid tomorrow

[doncolga]

Looking really nice!

[escapemcp]

Looking really nice!

Thanks for compliment. I have pretty well managed to hide the crappy wood that forms the exterior with bondo and duratex, although there is still the odd 'crease' where the veneer is coming away. I'll wait for it to get a dink and then sand and re-duratex. My first 2 cabs started with about 2/3 coats of duratex... I reckon they now have about 10 on them due to touch-ups, and 'can't be bothered to dust them, so just whack on another coat of duratex!'

Anyway, had a pretty good day today. Nothing much of interest to report. The pics will say it all I think:

#1 is my new stack... it just needs T30 #4 to complete it, which I am hoping to have built in the next couple of weeks. I do need to finish duratexing in the mouth of the horn, but I'll do this in the next few days probably.
#2 is the total mess that my workshop ends up in after a build. Tonight I have been tidying and hoovering ready for the next build, so it's nothing like as bad now

[escapemcp]

Just remembered, there were a few interesting things to report:
1) Using a single handlex2 config with the slims (one at the front base, and one at the rear top) is a bit of a no-no... the cab is just a little bit too top heavy. I'll probably just strap 2 together and carry them as if they are a 32" wide cab.
2) Luckily I made the 'rear top' handle (behind panel 11) go through both the top and the rear of the cab. I used a bit of rounded over 1/2" and glued this where the rear and back panel meet, providing a nice smooth grip. I forget who's build I saw this on, but whoever it was, thanks This means that I can easily carry the cab 'upside down', so that the high c.o.g. can be turned into a low c.o.g.=much easier to carry.

[escapemcp]

Both vids taken at low volume, although the 2nd was quite a bit louder than the 1st. In the second the tune seems to disappear as the camera approaches the sub... I guess that it is turning down the volume due to the SPLs going up as I approach the sub, but it must have then been too low for the phone mic to pick up!

[Charles Jenkinson]

Nice videos and great work! ...never had to turn the volume slider up in the youtube viewer before - nearly had me stumped. Is that just my PC got a wonky setting, or a property of the video itself...?

Mine (T30's) have gone on hold till after my do on Saturday (*), so Congratulations!, you win!

(*) Not because I'm a mard arse, but because we've got company next weekend and my J12L's and other gear has had to go in the garage where the subs are being built, so the spare bedroom can be tidied in time - to be blunt, it looked pretty tidy after I just moved the speakers out, looking at it with blokes eyes, but it's also a mental / karma thing.

You looked like you had loads of room in that garage there escape - it's a shame you couldn't have built 2 at once. Once I've built my subs, my garage is going to start getting cramped, but I've got at least one more build I think I need to do soon, an XF212, then we need a bigger house (with bigger garage) or an extra gear shed. The 'gear in a trailer' thread on here made me wince.

Nice tune too.

[miked]

Very nice, escapemcp! You do a great job of documenting your build and the Tubas turned out great! I like the color scheme; it's different than anything else out there and matches your OTops perfectly.

[escapemcp]

Nice videos and great work! ...never had to turn the volume slider up in the youtube viewer before - nearly had me stumped. Is that just my PC got a wonky setting, or a property of the video itself...?

Probably the vid... it was quiet on my PC too. Will wait for the neighbours to head out one day and then I'll make a proper video

Mine (T30's) have gone on hold till after my do on Saturday (*), so Congratulations!, you win!

Not really.. you are managing 2 at once (I wish I could have done, but the (lack of) wood issue put paid to that idea.

You looked like you had loads of room in that garage there escape - it's a shame you couldn't have built 2 at once. Once I've built my subs, my garage is going to start getting cramped, but I've got at least one more build I think I need to do soon, an XF212, then we need a bigger house (with bigger garage) or an extra gear shed.

Persuade the missus to get a bigger house (as if she would need persuading) in order to get a bigger garage... I like it!

Nice tune too.

I have many others

Thanks for the input. Hopefully we'll catch up some day when you are down here, or I'm up there. A few to many miles inbetween us at the moment to make a day trip.

[escapemcp]

Very nice, escapemcp! You do a great job of documenting your build and the Tubas turned out great! I like the color scheme; it's different than anything else out there and matches your OTops perfectly.

Thanks Mike (I assume this is your name ) I am very happy with the Tubas. I thought the slim might look odd next to the 24" wide ones, but I actually like the way the slims look and I don't think it looks 'funny' next to the wide ones. I can't wait to hear how they actually sound together rather than just seeing how they look.

Note: The green colour scheme in the wide Tubas will be changed to yellow when I can afford another can of yellow spray paint. Then they will all look like part of the family

[escapemcp]

Just been fiddling and it's sounding much nicer I took on Radian's suggestion of using a 12dB/oct slope @ 50Hz to remove the large rise in the T30's response from 50 to 100Hz (13dB - taken from the sales page) and the bass is sounding much nicer.

I have also been using the Dave Rat headphone trick (probably not his idea, but I saw it on one of his vids) to dial in the system. The trick is to listen on headphones at about the same volume as the rig, then take headphones off and compare the sound. I found that I was missing a fair bit of treble (~3dB) at ~12KHz-17kHz and also a bit of mid @~1k. Sounds much closer to a really nice sound now. Admittedly, this is all assuming that the headphones are producing an accurate sound, but I think they are close - certainly closer than before and TBH I like the sound of my headphones and I'm happy reproducing that sound on my rig.

[Michael Ewald Hansen]

Just been fiddling and it's sounding much nicer I took on Radian's suggestion of using a 12dB/oct slope @ 50Hz to remove the large rise in the T30's response from 50 to 100Hz (13dB - taken from the sales page) and the bass is sounding much nicer.

I have also been using the Dave Rat headphone trick (probably not his idea, but I saw it on one of his vids) to dial in the system. The trick is to listen on headphones at about the same volume as the rig, then take headphones off and compare the sound. I found that I was missing a fair bit of treble (~3dB) at ~12KHz-17kHz and also a bit of mid @~1k. Sounds much closer to a really nice sound now. Admittedly, this is all assuming that the headphones are producing an accurate sound, but I think they are close - certainly closer than before and TBH I like the sound of my headphones and I'm happy reproducing that sound on my rig.

You don't have a measurement mic and a computer? Makes it a lot easier to dial in your system when you can do sweeps and RTA's

[escapemcp]

You don't have a measurement mic and a computer? Makes it a lot easier to dial in your system when you can do sweeps and RTA's

Yes, I have the DEQ and Berry ECM8000 mic. I had done a quick RTA, but was just tweaking to taste. I need to get the kit out for a proper RTA session one day, but this probably won't happen until I have built the final T30, so without further ado....

[escapemcp]

Final T30

Started the final (for now ) T30 slim today. Cut out the driver access panel, only to discover this:

This is right on the edge of the access panel! I will probably remake the access panel (in birch... when I can get some). There is no way I could attach that panel tight without the screws just eating their way through that wood - I thought of using washers behind the screws and even then it would be doubtful if the wood would hold up! As you can clearly see that is some proper crap wood! Picture 3 is just a shocker! I have filled in any gaps by injecting PL into it, just to see what it would do, but I still don't think it will be any good.

I am now making this final T30 to see if I can do it. You know how in school you used to be set a maths problem and you would just about get it and think you had it sussed... but then they would set a similar problem, but a much harder one with much more to think about? Well this is how I see this build. I think that I have just got the T30 build down and then this wood turns up (ok.. my fault ). It has now become a challenge to see if I can engineer my way around this bad wood. I am actually relishing it and looking forward to seeing if I can pull it off and produce a T30 that sounds the same as the others. I will be reinforcing all joints with strips of BB, I think I will also be using 2 braces (except for the mouth) just to be sure that the sub is solid (as can be). If I fail, then I haven't lost much other than the wood (which is pretty well much useless anyway) and my time (which I have lots of at the moment). If I don't pull it off, I am certain that I will learn quite a lot along the way, so I'm just going to see what happens. Once the sub is 'in the field', I do not expect it to last very long with the sorts of voids in it like in the pic. I am assuming that this will have to be rebuilt after a few outings and I'm cool with that. It'll be another build for me to get my teeth into

PL'd panel 1 into place. Screwed it in with 5 screws from the underside (as seen from the photo). I ensured that there was plenty of PL in there (check out the squeezeout on pic #2!) to fill any gaps. The strip of wood that you can see in pic #1 is a bit of BB to demonstrate where I was originally considering the reinforcement to go. It is not glued in place or anything. I would attach screws into it through both panel 1 and the side, ensuring a more solid joint than trusting either a) the void filled wood or b) the veneer.



As there was so much PL, it was still drying this evening and looked like it may well take a while before I could take a screwdriver to it (and this is the 5 minute stuff!), so I went out for a pint When I got in I scraped off the excess and the angles are all within 0.2° - easily bendable to bang on 90° when I get the next couple of panels attached. I still need to attach the reinforcement strip(s). I was going to use that 1/2"x1/2" strip of BB to reinforce the joint on the 'outside' of panel 1 (as in the pic), but I then realized that the flange was on the other side of where I was going to attach the strip. I may well use the flange as reinforcement, so I decided to have a think tonight before I make any moves. The way I will reinforce will be to drive a screw through the crap wood and then into a strip of BB, 'clamping' the crappy wood in place - then repeat at 90° through the other bit of wood. I'll post pics tomorrow.

I am also uploading a video of a sound test earlier on today. It will follow shortly,

Note: If there is anyone on here looking at building their first cab, this is now a "How NOT to build a BFM cab" thread!!

[escapemcp]

Video of me testing earlier on today. Still no war volume vids Taken on a Samsung Galaxy Note II.



Having those 2 tops next to each other is not the best idea, but it's the only place for them at the moment whilst the build is underway.