BillFitzmaurice.info

Tom Smit wrote:So, it appears that getting involved with BFM cab building leads to cleaner, tidier shops.

Mine has currently been annihilated as a friend moves house. It has a whole rack of his crap in there and I'm dying to get some work done.

Tom Smit wrote:

escapemcp wrote:I am now just finishing off the build tonight by painting the braces (admittedly, the subs have been 'finished' for weeks, but not fully painted). Then I can call it a day on my first BFM build.... and I can start planning the second

Home theatre?

No... I rarely even watch TV these days, let alone films... music is my life now. Just going to have to build some more T30s, then DR250s, then T60s and then, a few years down the line, the cab that Bill is yet to design (or is currently designing???)

Now I have my Otops and I love them, but they were not exactly what I'd call a 'challenging' build after doing the T30s (and those were my first ever woodwork!). I was thinking of building another pair of Otops to double up but I am now thinking that a pair of 250s would have the same output as 4 OTops (is this right??) in a smaller pack space. I now feel that I would be wasting my time going the 4xOT12 route, when I know I am really lusting after a pair of 250s. (well, 12 actually )

I think I have just talked myself into it, haven't I... I might as well start my DR250 build thread now then

Will post gratuitous pics of the whole setup soon.

See I'd love a pair of DRs but man that's a complicated build! You're a brave man... I have a second pair of OT12s about 60% done and I'm more than happy with the sound on those. When you get the DRs done, post up and I'll come visit.

escapemcp wrote:

Tom Smit wrote:

escapemcp wrote:I am now just finishing off the build tonight by painting the braces (admittedly, the subs have been 'finished' for weeks, but not fully painted). Then I can call it a day on my first BFM build.... and I can start planning the second

Home theatre?

No... I rarely even watch TV these days, let alone films... music is my life now. Just going to have to build some more T30s, then DR250s, then T60s and then, a few years down the line, the cab that Bill is yet to design (or is currently designing???)

Now I have my Otops and I love them, but they were not exactly what I'd call a 'challenging' build after doing the T30s (and those were my first ever woodwork!). I was thinking of building another pair of Otops to double up but I am now thinking that a pair of 250s would have the same output as 4 OTops (is this right??) in a smaller pack space. I now feel that I would be wasting my time going the 4xOT12 route, when I know I am really lusting after a pair of 250s. (well, 12 actually )

I think I have just talked myself into it, haven't I... I might as well start my DR250 build thread now then

Will post gratuitous pics of the whole setup soon.

considering yuou have already invested in 12 inch drivers, I would either go the 4 ot 12 route, go 2 DR280s (same driver, can harvest the piezos as well), OR go dr250, plus a pair of jack 12s on the side for small gigs/monitor rigs.

Well I need a monitor, so may well build a DR250 for that and when I build the second one, the DRs will take their rightful place up front and the Otops will loiter behind the decks. DR280 would be to big (pack space) and then there is the dispersion issue... at free parties, everyone wants to dance with their head in, or close to a speaker!!
I do have the beginnings of a third Otop... well, it was my second, but it was a bit off and I wasn't happy with it, so I ditched it and started afresh. I was going to finish that, but I would have always been unhappy with it, so I think the DR for monitor and we'll go from there! I know it is all back to front, but I am working with limited budgets here!

I don't think the DR will be too taxing. I'll just work slow, follow the plans and if I am unhappy with anything, I'll do it again. This approach served me well for my wood working 101 on the tubas and I want to learn more. As those DRs sound better than the Otops (which sound so nice), I need them in my life and my rig!! I may not have the biggest (trucks and dodging police is much more difficult), but I want to kill other rigs out there on SQ! The DRs are not a major outlay in cash either (no more so than the Otops), and I am happy to spend ages in the garage building now... it's so therapeutic. I also have about 70 Monacor MPT-016 tweets that need to be used up

Once I have built the DR, you are more than welcome to come round 88. Can do a side by side and have a general day of fiddling with speakers and beer. Just a shame there won't be two of them so that we can run them in stereo.

News just in... for my next party I think I have managed to get a bouncy castle... GET IN!!!

there is no dispersion issue with the dr280. only with the compression driver version. otherwise you can build with a melded array.

sine143 wrote:there is no dispersion issue with the dr280. only with the compression driver version. otherwise you can build with a melded array.

Can you PLEASE stop making my decision making harder than it already is... I had a plan, but oh no... you just HAD to ruin it

So I could reuse the 2512s in a 280... seriously reduces those pesky costs. Back to the thinking room to work out where to go from here

I've never even looked at the plans for the 280s... 2512s in those eh? Hmm.

88h88 wrote:I've never even looked at the plans for the 280s... 2512s in those eh? Hmm.

Just been reading and recommended drivers are as with the Otops it seems (3012 (neo) or 4012 (non neo)). I have found quite a few posts about 250s with the deltalites in them though, so I am guessing that these are ok (although not 'ideal').

Does anyone know if I can re-use the crossovers from my Otops in the 250s? I would assume that as the (pizzo) HF section is the same AND the driver is the same (although loaded in a different cab), then the crossover points would be the same, which would therefore mean the crossovers themselves would be the same. Is this correct please?

I still have the majority of an 8x4 sheet of half inch (with just a v-plate 'bitten' out of one corner) and a box of about 70 pizzers. If I can re-use drivers, crossovers and use the spare wood and pizzurghs, I think I would have most of the DR280 right there. What else is needed that would require expense please? (I don't have the plans as yet, which is why I am asking for a bit of help).

Many thanks for this (and for all the help that everyone has provided throughout this build... it has all been invaluable and I wouldn't have made it this far without everyone's chipping in )

For most people the determining factor is size. For you, since you have lots of moving around to do I would go with 250's... Especially because all you really gain is 10-15 Hz crossover potential and (not sure about spl) the form factor gets much harder to single handedly deal with (listening to what people have said, no personal experience in this aspect). I can tell you from experience that you should save weight wherever possible, my 20 inch T60 weighs more than I was expecting, can't wait to screw those corners on but I really should paint first.

MissileCrisis wrote:I can tell you from experience that you should save weight wherever possible, my 20 inch T60 weighs more than I was expecting, can't wait to screw those corners on but I really should paint first.

On this point building a pair of T60s has made my T39s feel lighter than air... Do reps with T60s and everything else feels light in comparison.

I'm sorry for projecting my own wants onto your project hehe.

I have 4 otop 12s. they are great in stacks of 2 per side (1 per side is great for up to 150 AT LEAST). however the dr280 bug has been circling my head for months now. I dont own a car at all. for my big gigs, I rent a 5x8 trailer, which happily fits 6 t48s and 4 otops 12s plus other bit, and then beg around for someone with a trailer hitch. For thesse events, I'd have no worries upgrading to the dr280s, as they would easily fit in the trailer. the SMALL events are where problems begin to rear their ugly heads. where as I can happily sit an otop in the lap of every person in a honda civic (sans driver seat of course), I believe there would be more protests if I attempted to do the same with the 24" cube that is the dr280.

I just really want to hear 4x dr280s

Problem... I was testing the system last night with some sine wave sweeps and noticed that on one of my tweeter arrays I have got some distortion. It only happened when I turned the volume up, but saying that, it was still nowhere near war volume. As far as I can tell, this is going to necessitate unsoldering the whole array. Does anyone have any ideas or tricks how I could do this without having to unsolder the whole array please???
Tyvm

I've heard it's done using an empty kitchen roll tube, to listen to each tweeter in turn, whilst they're all on.

shouldnt be using sine sweeps into the tweeter range. they take much less power than the woofer, so if you were too sweep with anything higher than 50 watts with a sine I wouldnt be surprisded by distortion due to its low crest factor.