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Old 28th September 2007, 12:53 PM   #1
the joz is offline the joz  Australia
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Default Joz' Twins of Pleasure

OK I'll start my little diary chronologically here.

It's the story of the construction process of a pair of JBL 2245's.
Pics will follow soon,or at least a link to the pics............I hope!

Thanks.

OK
here goes the story of my DIY subs,well knind of DIY

DATE: 22.02.07

After visiting some audio friends of late I have come to the realisation that deep bass is goooood! and the fact that although I have a capable sub it could be much better.
Anyway over the last few weeks i've been listening to very impressive subs,both Infinate baffle and boxed.

Another very good freind of mine seems to be a never ending source of hi-fi technical knowledge and is always suggesting the DIY thing to me.As he is the one person that I know with so many projects at various stages of completion.He has forever sung the praise of JBL subwoofer drivers,along the way he has worn me down and pointed out a pair of boxed JBL 2245 18" drivers on E-bay.They are in a box like those ugly un waf freindly stage type boxes with the fuzzy externals.
Anyway I kept an eye on them placed one bid out of two total bids and I won them
Origainaly I had contacted Andrew(Aslan)if i could get them to him but now the drivers are being freighted home only.Thanks anyway Andrew for offering mucho appreciated.
So now that they should be arriving sometime next week the planning is to start.

Link to JBL 2245

http://www.jblpro.com/pages/components/2245h.htm

Each cabinet is to have a volume of between 250-300 ltres.
So I'm looking at a cabinet with the demensions of,
H:600mm.
W:1000mm.
D:500mm.

So two cabinets like this side by side to run as dual/stereo subs.
With the height I'm wanting to acheive I was planning a sort of bench top scenario,this way they would look more like a low line cabinet fronted with grill cloth rather than additional large boxes,and I like the little feet AJW has under his Australs(very nice).

Dilemma 1.

At this stage I'm not sure which way to go with regards to power supplies?
Do I go the way of plate amps or separate power amps with an external crossover?My issues are that I want the best possible intergration and don't know what will offer me whats best?.At the moment I still have two free channels on my Elektra amp,this may do for a while.

Dilemma 2.

The finish? They need to look non industrial because they are in my lounge.
May go plain black,then get a nice top with side panels sprayed in two pac?
This way it would look like one peice of furniture,Happy wife

Dilemma 3.

The thought of three of these muthas across the front is oh soooo tempting.All in an LCR configuration.
I wonder when it will become to much?.
This means finding a third driver,though my mate said if a pair do come up he wants another aswell(he's truly nuts)
I'm not really after the loudest subs around,but that extra headroom sounds nice.

Anyway I hope I haven't jinxed myself with my over the top plans and hope they do arrive safe n sound next week.


Link to pics below

http://www.dtvforum.info/index.php?showtopic=50524&hl=
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Old 28th September 2007, 02:08 PM   #2
the joz is offline the joz  Australia
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DATE: 26.02. 07

Arrrgh!
While the guy was removing the drivers he slipped and put a screw driver through the cone.
So I am now waiting to see about the outcome of a re-cone?
A genuine re-cone kit is $380+labour,a non genuine is about $300 all up.
So we're trying to work out a repair or adjusted price..........Why me??

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Old 28th September 2007, 02:12 PM   #3
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DATE:. 28.02.07


Ok we've worked out a deal.The big JBL 2245s are on their way down south,I hope.I mean I've been separated from my $$$.


The other day I was in at Aranmar(Acoustic Developments).http://www.acousticconcepts.com.au/Where I met Greg Osborn.(local speaker builder in Melbourne)
Anyway, this is the place Osbourne amongst(Note Perfect)and others have their cabinets manufactured.So I'm just getting a ball park figure about the costs of cabinetry.As per the specs previously,heavily braced with 33mm thick cabinets in Bubbinga gloss?Lots of stuff going on here.I'm wanting them to match the cabinets to my Whatmoughs(front bevel)not so much color.I'd rather not get those sharp edges or quad looking edges that John(owner of Aranmar)and Osbourne seems to like.
Nothing seems to be a problem.I'll wait and see how many $$$.John the owner showed me pics of quite a few jobs,geez there are some extreme people out there!

Firstly only time will tell.I already have a hole in one driver

Then I'll have to decide about whether to use plate amps or separate amps with an active crosover?..........and and and?...............My wifes gonna love me......not!
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Old 28th September 2007, 02:13 PM   #4
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DATE. 02.03.07.


The drivers arrived today, they're bloody huge.I didn't think that they'd be that big.
Oh and the hole is just in the foam surround,of to speakerbits on Monday for a repair and a checkup.Oh and the guy who I bought them of sent down a re-cone kit for the speaker because of the damage.Unfortunately it is for the JBL 2241 not the 2245,both 18"ers but does not suit.So I'm sending that back to Sydney for a refund.
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Old 28th September 2007, 02:15 PM   #5
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DATE. 25.03.07.



Latest news on the 18"ers.
Rang Speakerbits on Thursday to see how my drivers a going,that is are they ready?
Umm! oh yea! was the kind of reply I received.
Anyway,it seems they'd kind of forgotten about them and what they were doing with them.Maybe they should have checked their quote for me
Looks like they will be ready for pickup Tues/Weds,I hope.
Makes me wonder if I should have gotten them done across town at a place called Total Recoil??
I suppose no hurry anyway,John from Aranmar Accoustics still hasn't gotten back to me with cabinet quotes either.
Just makes me wonder how many industries or people actually bother honouring their word when they say thet will do something??
I know these guys are busy and are very succesful and good at what they do but geez its a pain in the bum chasing them up continously.

Hopefully soon things will pickup some momentum so I can install these suckers.

Though so far I'm looking at external crossovers with parametric eq from Behringer,though I maight look at what is available from Rane.
Power wise I'll more than likely be going for either.

All secondhand,all stereo amps.

Behringer EP 1500 @ about $400,digital and looks near new.

Crown K1,also digital.not sure about the $$ yet.

Yamaha(model??)this is a class A/B @ 350watts/8ohms for about $750??
this is quite retro with VU meters.

So far I'm leaning towards the Yammy because of what it can do with an 8ohm load as this is what the drivers are.Also I want to have plenty of spare watts as I know that EQing the drivers will chew up lots of power.
Both the Behringer and the Crown quote some enormous figures butthese are into 2ohms and I still like the thought of class A/B as opposed to class D.

So hopefully more updates much sooner.


Well for the two drivers just over $1100 I think,thats bought,shipped and rebuilt.
For the amp which if I go the more powerful class A/B Yammy 350watts RMS/channel at about $750
Say a Behringer active crossover approx $200?
Then the cabinets,I'm hoping for under $1000 for the pair,finished in real wood veneer,heavily braced 33mm MDF??Maybe a bit more because the one thing I don't fancy about Aranmar cabinets is the front edge with the standard quad finish.I want the front edges with a bevel to match my Whatmough P's.This is just personal taste of course as my friend only likes square edges.
So they will come back at about $3000 for two.But I still envisage some extras as thing always seem to blow out.
Though a bit less perhaps depending on the amplification??

Oh forgot to add feet for the cabinets,????? I don't think I'll have them sitting on the floor or on a plinth maybe?
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Old 28th September 2007, 02:17 PM   #6
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DATE: 28.03.07.

no progress yet at all.Just rang speakerbits to make sure they were ready for pickup.

Guess what??NUP!!! just more excusses.

Now I know I should have driven across town to Total Recoil
So much for the wrap they got the other month in Aus Hi-fi mag..
I just have a feeling there is going to be more grief with these guys.

Anyway they said Fri if thats ok?
Like I have a choice!
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Old 28th September 2007, 02:19 PM   #7
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DATE: 02.04.07.


Picked up the drivers today ,YIPPEE!!

Looking very sexy now.
Anyhow they had found some new old stock original recone kits,so old that the surrounds had perished while in stock.So they fitted these and replaced the foam surrounds.So now they are both new and identicley matched, bad news is $500 for the job .Still cheaper than new recone kits which I was quoted at $550 each + fitting
Still at least I'm past step one Now I've just got to get some plans to Aranmar,I think he's too busy to worry about my money But I will be persistant.Speakerbits have been kind enough to model me some plans for the drivers.I should get them tomorrow by e-mail according to them,I'll be waiting for them.

I feel if I get ten years from the sorrounds it'll be good,more than likely I'll have something else by then anyway?
I felt that if the originals were designed with foam I'll keep them that way.Even though I was given a choice I chose foam.Also foam surrounds seem more compliant than rubber so i didn't want to change that either.
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Old 28th September 2007, 02:20 PM   #8
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DATE. 13.04.07.


Went to see John at Aranmar again yesterday.
I was greeted with Uh Oh! heres trouble I've forgotten about your quote.

Anyhow I spent an hour or so there,going over box sizes with him and talking stuff.What amazed me was the huge difference in internal volume compared with the external demensions,I suppose 33mm thick cabinets with lots of bracing will do that.I think i'm loosing about 100 litres of volume in comparison to the outside measurements.
It seems like there is a huge holdup with Bubinga at the moment as its still in transit.So a few people are bleeding about it(osborn)
As this seems to be the most popular finish at the moment.So at best he thinks mine will be at least 6 weeks.
But what I saw in production were the cabinets for the Redgum speakers,both floorstanders and standmount.Wow what a beautiful finished cabinet,in their high gloss timber veneer.I'm a bit excited now
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Old 28th September 2007, 02:21 PM   #9
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DATE. 19.04.07.


Was down at the workshop again early this morning nutting out a few details.Like edge details and grill styling.
John is going to E-mail me some graphs of slightly different size boxes.
My cabinet budget has just been blown out Oh well,they'll be with me for a long time I suppose.
The bride may not keep smiling though
At least there is progress happenning.

ATM,The moment the veneer is Bubinga.But I must investgate the other timbers just in case.

Though I'm going for a satin finish.The reasons being for satin are.......as much as I think gloss is stunning.My kids would leave paw prints all over them,then there is the dust and I'd be shattered as soon as the first fine scratch appeared in the high gloss finish.And I'm sure that would be inevitable.

Then of course there is the price premium per speaker cabinet.Because these are huge),at about $200/box just for the gloss........Hmmm? already getting exxy without the gloss.I had to make sure john could deliver them aswell. No way I could transport and move these by myself.
I'm glad the bride loves me

Well my first visit to Aranmar was about the 25/02.
Now its the 21/04.
So I reckon at the current rate 4 months is about the turnaround time.
I've worked out now that with John,tomorrow means in a week

I'm also concerned where the roll off is rather than the highest spl is acheived.So hopefully with some room gain and a bit of EQ we will be able to achieve the desired response.
To gain the extra SPLs I suppose I'll just have to throw some extra watts at them
So with any luck I'll find time to get to Johns soon to discuss a few more things.
Still trying to make up my mind about what kind of edges I want??May just get square edges without the bevel??
Though I think I'm having a black baffle and back with timber veneer top and sides
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Old 28th September 2007, 02:23 PM   #10
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DATE. 11.05.07.

Hi guys, they lastest update as of yesterday is..........


Well,I'd emailed John during the week with a handful of questions to clarify what the sub was doing at what levels,eg SPLs/watts,cone excursion,frequency graphs,box tuning,port sizes/number while relating to different volumes and a handful of other questions.We needed to know what was the ideal volume of the box in relation to the performance that we'd want to achieve.
None of which I'd thought of myself BTW But JA who is good freind of mine and who seems to really know this stuff quizzed me on all this.
I think he realised I needed help when he saw the blank dumb look on my face

Anyhow I received a return email from John suggesting that I made my way over to his factory to do all things in real time.He didn't want to waste time going back and forwards,fair enough.We both wanted to finalize this and get it signed of to start.
On this trip I took JA along with me,thank god!
As JA at a glance(split second) could understand all the graphs,with me it took me ages just trying to focus on and understand which graph we were looking at.

While meandering around the factory with John and JA was like a treasure trove,with the amount of loose drivers of allsorts and speaker boxes of all shapes and sizes.Couldn't help but wonder what would be possible.Mate there are sooo many speaker systems just waiting for assembly in there.
JA had spotted a handful of old JBL horns suited for compression drivers,I could see his mind ticking over.I know he wants some for his upcoming project.

The finish will be satin bubinga,but it seems the last shipment into Aus was a bit of a dud,so will be waiting for the next one a few more weeks

So the boxes volume is confirmed now at 250lt and what I like is that with 50 watts it had an SPL 120db at 25hz(if I remember correctly?well more likely I'm wrong)I will confirm this later.This is with out any EQ at all.So what I'm trying to acheive is from this is effortless bass with plenty of headroom down to about 20hz,from there it can just roll off......Remember I'll have two of these running in stereo.

Also because the impedance doesn't drop below 7 ohms,I don't need super amp the can deliver 2400 watts into 1ohm.Hey,at 95db sensistivity they don't need much.A stereo 2-300 wattsRMS(500watts/4ohm) amp will more than suffice
I'll see what the spare channels on the Elektra can do,but no doubt I will be investing in something that is capable of 2-300watts/channel.Some nice second hand units around for this,though auto signal sensing would be nice.

Oh,I just have to make up my mind on the feet for it,it's either some small flat stainess steel disc type ones or a flat wooden plinth with a felt bottom.Either way all I want to see is just a shadow line under it.


So now I wait
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