BillFitzmaurice.info

Using clamps/screws and straight boards you can easily push/pull warp out.

Hi everyone.

Well, the T30s are done and in service! They have actually been finished since the end of January but I didn't get around to posting... Please see pics of the completed units at the bottom of the page:
http://imageevent.com/beales/other/speakerbuild

Note to self: Pictures of satin black objects taken in less than brilliant light do not come out well. Use more light.

As you can see in spite of the mediocre photos, the subs really did come out great! I put a good bit of time into bondo-ing and sanding the screw holes and beveling the edges of all the parts before painting, but the results were absolutely perfect after application of the finish. And I loooooooove Duratex! It really creates a nice looking "industrial" finish that covers up those last little imperfections. My biggest finish issue was a very small gap along one of the side joints, but the Duratec disguises it and you easily overlook it. Over all the T30s look completely "pro" and I'm very happy with the results.

The bigger question, bigger than how do they look, is how well do they work. My response would be "very well" or possibly "great". Notice I am not using exclamation points or capitol letters. These puppies get very low and play very loud. With the BP102s they do not knock you over though. After all that work and effort, plus not inconsiderable expense (I have about $400 in the pair) I was hoping to be blown away. They definitely bring a smile to your face, but they do not elicit "Holy s***" from the listener. At this point I'm wishing I had spent another $150 on Lab 12s right now, as the cabinets are the same amount of work to build, but you can get more volume/power out of them.

The T30s have been used in two gigs since they were completed. The first was a little disappointing as it was outdoors, and y'all know how hard it is to get good sound outdoors. The subs just couldn't create the desired effect, plus were difficult to integrate with the tops. With the BP102s, 2 x T30 are not enough for outdoors, and I doubt they would be enough with the higher power drivers either.

The second gig was in a room that was about 50 x 80 or maybe 50 x 100. That went much better. The DJ set the V-plated subs up in the corner of the room and the tops on either side, also at 45 degrees to the room. This worked out really well, with enough bass in the Dubstep tunes to provide the desired "chest feel". If he always got to pick his room size and placement he would be set!

So, I'm very happy with the way the cabs turned out, and happy with the performance of the units, but not deliriously happy. You know what they say... "Too much is just enough", and I ain't got enough. Next time I will know what to expect, but next time will have to wait until I forget how many nights and weekends it took to build them, and for my wife to forget how long she would have to give up the garage.

Thanks again to all who offered advice and support, and of course to Bill for his great design.

Gary in Atlanta

Good work!
And there is nothing wrong with the pics! They're good!

And, if you double up on the cabs (along with a driver with more Vd), you will have that silly smile.

Those look fantastic, very nice finish. Also with regard to the performance not quite being what you were hoping for, that's why I went all out and just plumped for the recommended drivers for my T39s. It was a case of wanting to see what the top end would do first before maybe considering downgrading. All this means now is you'll have to build him another pair of T30s to stack and plate on top.

88h88 wrote:All this means now is you'll have to build him another pair of T30s to stack and plate on top.

+1

Then he'll harness LOUD and LOW

I'm sure that I'm not the only forum member that appreciates your honesty and critical review of the T30's performance. No doubt a Lab 12 / 3012lf retro fit would yield some additional dB (can anybody chime in with spl charts?)
I'd definitely go with 88h88's advice in building a further two T30's for economy and scalability, this would make a healthy increase by doubling the amount of cabs.
However Leland does the BP102 for $79.95 The Lab 12 for $159.95 Purchase price for four is $639.80, vs $159.90 for another two BP102's, its a tough choice only you can ultimately make. How much is the young Dj keen to contribute?

It would be great if a fellow forum member could do some V.d. & Volts equations of four BP 102 loaded T30's vs two Lab 12 loaded T30's or even four of them. Plotting the results onto a spl chart or using one of the spl calculators to see just how much more you would get out of twelves opposed to tens. With those figures at your finger tips then you would be truly armed to make the best decision. Show the raw figures to the DJ and encourage him to save his own earnings. Sounds like you're having a break between builds anyway so its to his advantage really, the longer the break the more likely he will have more to contribute to 4 lab 12's

Thanks guys (I assume guys...)

Yep, taking a break.

The other issue is that we (he) doesn't have enough amp power to push another pair with BP102s, nor a replacement set of Lab 12s in the current cabs. As they sit, the crossover is running wide open and the amp is running at 7-8 to hit the 30v limit. To drive another pair of subs would require a new sub amp, say a Peavey 1600 (or something) for an additional roughly $275. Plus the $400 for another pair of BP102 cabs, or even just the cost of the Labs we are talking a chunk of change.

The great thing (for me) is that it is up to the DJ to either save up the money, or be happy with what he has and what he can deliver in a given size room. If he wants to build another pair we can do that, but it is on him to fund it and do more of the work. I feel like I did a good job setting him up with a starter system. He can take it from here.

Not to worry, BTW. I build my own hi-fi speakers and tube amplifiers, plus I have cars and a motorcycle that can always stand to be cleaned or maintained, plus it is time to start getting the garden ready (here in Georgia), plus my wife is talking about putting new flooring in the family room. I will have no trouble staying busy.

Thanks again.

Gary

Gday, so I've done a bit of research of drivers Vd & Volt limits.

The BP102 has a Vd of 207cc (c/o eminence specifications) in a T30 it must be limited to 35 volts IITP
The 3012lf has a Vd of 496cc (c/o eminence specifications) in a T30 it must be limited to 50 volts IITP

The 3012lf with similar frequency response to the D12lf delivers 6dB higher output with Vd 496cc vs. 243cc. IITP

Looking at these statements, would I be right to assume that two 3012lf loaded T30's with a Vd of 992cc would have a greater output than four BP102 loaded T30's with a Vd of 828cc? Could somebody help the O.P. and myself out by validating or correcting my statements

Thanks all

Gardening? Awesome thats what I do for a crust if you want to talk horticulture I'm all ears! Its approaching Autumn here - so you must be coming into Spring yeah? Busy time for green fingers I take it.

Titanium Hand wrote: I do for a crust

Uhhhh??

LelandCrooks wrote:

Titanium Hand wrote: I do for a crust

Uhhhh??

Laughing, really really laughing.

Leland,
"Earning a crust" in Australia is another way of saying "what I do to earn a living".
So in your case if I was to say to you "How do you earn a crust"? your response would be " I sell drivers, speaker cab building components for a couple of designs, and make cabs for people"

Not sure what you call it, but the outside, harder bit of a piece of bread is the crust...

We have a number of other equally confusing sayings.
Lots of it derives from English roots, in particular rhyming slang from the cockneys.
Eg: trouble and strife = wife/partner/girl (SWMBO)
china plate = mate
My apologies to the OP for the huge diversion, but it just had to be explained!

LelandCrooks wrote:Lots of it derives from English roots, in particular rhyming slang from the cockneys.
Eg: trouble and strife = wife/partner/girl (SWMBO)
china plate = mate
My apologies to the OP for the huge diversion, but it just had to be explained!

Thats it, spot on, I can deliver a few of my favourites...

Twist & Twirl = Girl, Missus, Girlfriend
Jack & Jills = Pills
Dead Horse = Sauce / Tomato or BBQ generally for the old 'Pigs Eye' = Meat Pie!
Three Wheeler = Sheila (colloq. woman)

and the old riddle goes "Whats The Colour, of a two cent piece", said by one brother to another when the Billo's are sighted. A two cent piece was copper.

Will any one school me on the Vd. scenarios from a few posts earlier? Cheers

beofservice wrote:The other issue is that we (he) doesn't have enough amp power to push another pair with BP102s, nor a replacement set of Lab 12s in the current cabs. As they sit, the crossover is running wide open and the amp is running at 7-8 to hit the 30v limit. To drive another pair of subs would require a new sub amp, say a Peavey 1600 (or something) for an additional roughly $275. Plus the $400 for another pair of BP102 cabs, or even just the cost of the Labs we are talking a chunk of change.
Gary

Out of interest, what amp is it and what kinda setup is he running? Are you using a single amp for both tops and subs? If not there's the possibility of running both pair of subs in parallel...

Titanium Hand wrote:Gardening? Awesome thats what I do for a crust if you want to talk horticulture I'm all ears! Its approaching Autumn here - so you must be coming into Spring yeah? Busy time for green fingers I take it.

Really early for planting here, but one could put in lettuce and such right now. We had a 70 degree (F) day today, but we are not safe from freezing yet. Another full month for that. If I was smart I'd build a little hot house from left over hunks of Arauco and plastic and get my tomatoes started.

Gary

88h88 wrote:Out of interest, what amp is it and what kinda setup is he running? Are you using a single amp for both tops and subs? If not there's the possibility of running both pair of subs in parallel...

He runs an old Altec 1269 and an old Gemsound 550 amp. Each pushes around 125-150 watts/ch into 8 ohms, and he runs the tops off of one and the subs off the other. The tops are EV "Force" models with a 15 and a decent CD horn. They are efficient and play much louder than the subs. He runs a DBX 223XL (again, ???, I can't remember these model numbers for sure) crossover. He does not yet have a limiter, but I may buy him something for his birthday.

We've tried stereo, summed, and mono, and stereo actually sounded the best. Both amps can be bridged, but neither is rated for bridged into 4 ohms, so no go. Once you do the math I don't think bridging buys you that much anyway. The components are all mounted in a portable rack, can't remember the brand. I think it is 10u, but the older amps take up a lot of space. The rack is plastic with aluminum hardware, and a cover for each end.

Source is a notebook PC with a Mackie external USB sound card. We thought about going Mac but they cost a lot |-=

Basically, I tried to provide him with a good "get off the ground" system that he could gig with as long as the venue is not too large. It is up to him to try to earn some money with it if he wants to upgrade. Naturally it would sound better with more power and more subs, but if that is what he wants he needs to make it happen.

You've got one seriously lucky son Mr BeOfService!

Sounds like he's got a great starting point and what better way to earn some money than DJing. As his talent grows, networking throughout high-school or college should readily supply plenty of opportunities to practice and hone his skills for when he can pick up the better paying parties!
I guess if he's talented enough he can earn some loot to build up his rig to truly wow and pound his audience!

Nice Work

Have you broken in the drivers? It should be much better than a pair of $200 speakers. Running your subs in stereo might feed them less than optimal results. The signal needs to be the same to couple.