Tuba30 + SLA Pro

[Bill Fitzmaurice]

From what Bill has said in the past, the placement isn't critical, it's just there to reinforce the structure along the corners.

Its function is to prevent phase cancellations from panel to panel reflections in the corners. But it doesn't have to extend across the cab uninterrupted, nor must it be airtight unless there are jacks or casters etc behind it.

[SirNickity]

Oh, OK... Is it the same as the "reflectors" in the THT? I read the 30-page thread and there was something in there about them not changing response at all, but helping with integrity. I assumed this was similar.

[SirNickity]

Day 10

Not much done today.. got the braces installed in sub 1, and an update on sub 2.

Almost there...

Spent Friday getting cables and electronics together. Installed OS X 10.7.3, Traktor Scratch Pro, and Studio One on the computer, downloaded updates, and other assorted maintenance. Pictures of the rack layout later, if anyone digs that sort of thing.

Day 11/12

A milestone today:

FINALLY. One side panel on.

Spent a little while filling holes, test-fitting the driver, and preliminary leak-testing. All clear, except of course the gaping hole in the side of the box where the access panel will go. Also some minor leaks around the gasket, but that's to be expected since I didn't tighten it down. (I'm a little nervous about spinning a huricane nut. I did use epoxy though...)

Just for fun, I powered the speaker from a headphone amp I built with OPA2134 op-amps. I wasn't bowled over, of course, but it was clearly audible throughout the garage.

Uh oh -- no limiter! There are hundreds of milliwatts here, completely unrestrained...

Obviously, that's not adequate for leak testing, so I substituted a 50W LM3886-based plate amp instead. I got upwards of 8 volts on my voltmeter during peaks, but it was getting close to 10pm, so I wasn't willing to push it any further. With a 25Hz sine, at around 3 volts, the parts bins hung from the wall were rattling incessantly. Kneeling in front of the horn mouth, my pants leg was vibrating. Very little audible sound though, and most of that was from the vented pole piece breathing. It's an interesting sensation.

DIY active sub? Nahh...

[SirNickity]

Day 13

Slow and steady progress on sub 2 -- got the isolation box built around the jack cutout, and the panel 11 corner piece (clamped and curing, not installed yet in this shot.)

Younger brother

And, not a moment too soon, 8x Alpha 6Cs and 14x piezo tweeters for the SLA Pros. 17 days spent in USPS purgatory. Word to the wise: Do not use parcel post if you are under a deadline. It will take a year off your life, wondering where your parts are. The online "tracking" is useless. I think it still says "Pickup or accepted".

Three days before the gig -- what a relief!

Wait -- do you guys see the piezos? Let's check the box:

Uh oh.

No piezos.

Also, someone seems to have put the box in a paint can mixer during delivery, and one of the parts baggies opened up. I haven't counted screws, but some of them fell out when I dragged the box across the floor, so there's probably a postal truck with hurricane nuts rattling around.

Elation and relief, followed by a sense of dread, knowing there's no way you can order the missing parts in time. Looks like I'll be running the SLAs sans-tweeters. Look, excrement occurs -- I ordered some grilles from Parts Express and every corner is bent. Luckily, I only need about 2/3rds of the material, so the middle part will be fine. Mistakes happen, and Leland got this box out on Memorial Day weekend, before everything shut down for three days. It's possible they are in another box that just hasn't arrived yet. I emailed to ask, but haven't heard yet. (Maybe he's on vacation, or on deadlines of his own. Who knows? It's my emergency, not his.)

Moral: Next time, order with enough time to make sure the parts are here well before they're needed. Hopefully the 6" Alphas can be coaxed into providing enough HF extension to do the job. These will be moved to a secondary area, and my Yamaha Club Vs will be pulling mains duty, as usual. (TBH, I don't know if the SLA Pros would have covered the main area anyway.)

Speaking of which, it's well past time to get started on those. It hadn't really sunk in how small these drivers actually are. Here's the pattern, with my big fat hand in front of it.

I thought it would be bigger...

Took the day off work, and by 4am, I had this to show for it:

Coming along much more quickly than the Tubas.

[SirNickity]

Day 14

Two days until showtime.

Got the tophat flush-mounts done.

The one luxury I made time for.

I've come to the realization that finishing work is going to be minimal. I hate going to a gig with bare wood -- it's just not professional. But, with one more evening remaining, there's no way I'll get the primer and paint on these things. (I haven't ordered Duratex yet, so I had planned on latex primer + flat black paint.)

I'm still torn on what to do with the tops anyhow. Duratex... paint... carpet... Hmmmm.. I know rat fur is going out of style these days, but I still think it's a fitting look for a PA speaker. I don't know. Looks like I still have time to decide.

Braces cut and installed:

These things practically build themselves.

If you've built a set of these, this may look a little larger than you remember... Well, they are. I lengthened the front-to-back dimension enough to add a plate amp. It became clear early on that designing the PCBs, ordering the parts, assembling the electronics, having the plate CNC'd, etc., etc., was not going to happen in time, so they will be passive for now. As such, they will likely get an uncerimonious 1/4" hole for the wire to poke through instead of a proper Speakon plate (though I ordered some, just in case.)

Yes, the bar is just getting lower and lower... At this rate, I may end up with eight cardboard Eminence boxes with holes cut in the fronts.

Back to the subs...

So much more complete with that side panel on.

1/10 braces installed, panels 11 and 13 installed, and finally, some access cover flanges installed. Those were done throughout the day, due to limited number of clamps -- and space to fit them in.

It's almost 2am, and I have to work tomorrow, so that's a wrap.

[67baja]

Keep up the good work. Lucky for you, 'tis the season of 24 hours of sunlight in AK now. Right? Coincidently, my daughter is in Anchorage right now to help a friend move back to Las Vegas. That's a long fookin drive back to the states for them.

[Jon Barnhardt]

Looking good. My advice would be focus on the subs to get them done and rent a pair of tops for this gig. Don't rush through doing sub-par work to get ready for 1 gig. You will be much happier in the long run if you take your time and have polished product to show for it...

Also the SLA's without tweeters are going to sound very muddy...

[thekl0wn]

Lookin' dang good. You've passed me up on the build... By a long ways!

I'm still amazed at how small all of it is on the SLA's... The drivers... The holes... The entire cabinet... I'm just itching to hear 'em!

[SirNickity]

Keep up the good work. Lucky for you, 'tis the season of 24 hours of sunlight in AK now. Right? Coincidently, my daughter is in Anchorage right now to help a friend move back to Las Vegas. That's a long fookin drive back to the states for them.

Yeah, it's getting close to Solstice. When I look out the garage window and see it's starting to get dark, I know it's really late. Soon after, when I see it's starting to get light again, it's definitely time for bed! Since Anchorage is a coastal town, Midnight Sun might be a stretch. It's more like midnight partly cloudy.

Looking good. My advice would be focus on the subs to get them done and rent a pair of tops for this gig. Don't rush through doing sub-par work to get ready for 1 gig. You will be much happier in the long run if you take your time and have polished product to show for it...

I had a moment of clarity yesterday evening, as I was putting the finishing touches on the Tubas. (Well, "finishing" as in... "useable".) You're absolutely spot on about this. I've been trying to rush within the constraints of getting them done now without impacting my ability to go back and finish them properly. But, as I looked over at the SLAs, still half-assembled, the cost in time to get them finished would mean compromises on the quality of all four builds. I realized, I had made no commitments as to providing multiple zones -- this is just something I wanted to do, and it became an immutable goal somewhere down the line.

Without tweeters, in bare wood, having to pull an all-nighter before the gig, just to have better coverage in an area where, realistically, they can still hear the main system? Nah, not worth it. The Club Vs are good speakers -- I have no intention of replacing them, just augmenting them. They're actually combo monitor wedges and mains, which I find very flexible, and I'm not entirely sold on the idea of using horns on the stage. So they're sticking around anyway. They've done well enough in the past, and there's no reason they wouldn't do well here. So, I relieved myself of the burden of having to finish the SLAs in time. Bummer, but I was making it out to be much more than it is. This turned out to be the right decision. (I'll post a follow-up later on the gig.)

Lookin' dang good. You've passed me up on the build... By a long ways!

Thanks -- but it got that way at the expense of four weeks of constant work -- to the exclusion of everything else. If you have the option not to do it that way, definitely take your time. This wasn't much fun, and it should've been. I've barely seen my S.O., the cats are not happy with me, and I'm completely exhausted. I have the house to myself tonight, so I think I'll take a break from the garage and kick back with a movie or something.

I have the utmost respect for those that can summon these things into being within a week. I don't know how you do it.

I'm still amazed at how small all of it is on the SLA's... The drivers... The holes... The entire cabinet... I'm just itching to hear 'em!

Same here. The portability aspect appeals to me for smaller gigs... that's the primary reason for wanting to build them active. But, I'm also intensely curious how they handle being driven hard. I used an Event 20/20bas today to cover the dining hall area, and it wasn't quite enough. It wasn't intended to be, so that's fine, but I bet that sort of thing would have been the ideal territory for the SLAs, or even a mini SLA pair. Definitely need some DRs for outside, though.

Oh, and as for the missing piezos -- naturally, Leland's on top of things. It's probably for the best anyway. Having the parts would have tempted me to coax them into some semblance of completion. Just the will of fate putting me in my place!

[LelandCrooks]

For the last few weeks all I've been on top of is the dung heap. Man, with the move, the spike in biz that's occurred this year, I've been making more mistakes than usual. Plus getting stuff is starting to be problem.

[SirNickity]

Moving will do that to you! Like I was saying before - even in the best of times, from vendors with highly automated shipping processes, there are still mistakes. You've been great about trying to make sure I have what I need when I need it, despite just being one of many fish in the sea. It's hugely appreciated sir.

[bitSmasher]

the cats are not happy with me

obligatory pic of cat in sub mouth, please

[ontime1269]

Day 14

Two days until showtime.

Got the tophat flush-mounts done.

Question from a novice woodworker, what do you use to flush mount the top hats?

[Bruce Weldy]

Day 14

Two days until showtime.

Got the tophat flush-mounts done.

Question from a novice woodworker, what do you use to flush mount the top hats?

Put rubber feet on the bottom for storage and you don't need to flush mount it.

Otherwise, rout it out.....

[SirNickity]

Yep. Measured the diameter very carefully and made a circle jig for the router, with a measured plunge depth pre-set. I then re-used the 2-1/4" hole saw from the tweeter cutouts for the "tube" of the hat.

I need to find a good variable circle jig. My router came with a fence that can be used as such, but only for large diameters. Any suggestions?

Cat-in-horn picture forthcoming. I haven't brought them into the house yet, but when I do, it's only a matter of time...