Omni 10

[clauster]

After much deliberation I've just started ordering the bits for an O10 - not the widebody, but adding an extra inch in depth to the cab. Why? So it will stack neatly ontop of an O15TB sub should I feel the need for more bass :-) Going with a four element cut & glued piezo array (switchable for on and off).

Piezos ordered (+1 spare) and BB ply too.

Off in a mo to order drivers and misc bits.

[ped]

Now I have my own garage I am considering undertaking such a project myself. Looking forward to reading the progress and seeing the pics.

ped

[clauster]

Build should be commencing in two weeks time, until then it'll just be pics of bits in boxes I'm afraid

[gilmour]

[quote name='clauster' post='254402' date='Aug 4 2008, 01:58 PM']...Why? So it will stack neatly ontop of an O15TB sub should I feel the need for more bass :-) Going with a four element cut & glued piezo array (switchable for on and off).[/quote]

Nice one, it's a great project to undertake, but if you feel the need for more bass then don't go for the O15 sub (IIRC Bill doesn't recomend it) build a 20" wide Titan Sub.

Now get with making sawdust, and make sure to give us lots of updates

[david_l_perry]

Looking forward to another Omni build !!

I would be more tempted to stay with the widebody to allow a little more wiggle room for the piezo array. Its not a wide cab. Here is a shot of my full width omni 10 (this is the one I brought down to the Basschat meetup in Lytham) sat ontop of my old garage bound Little compact Peavey 2x10TX



I built mine to allow trying alternate piezo array options and built it using a seperate sealed piezo box in the top half as you can see here so I could swap the straight array and melded array (for what its worth the melded array is far, far better)

(not much spare room either side)



Its a [i]great [/i]sounding cab, but for me and my Status Bass I wanted the extra lows of the Omni 15, so built one of those and sold the Omni 10

Dave

[clauster]

Gilmour, cheers for the tip re sub. I wasn't aware of that, I'll have to do a search on Bill's forum.

David, thanks for the advice about piezos. I've read and re-read (several times) all of your build treads on all three boards I follow and am a huge admirer of the cabs you've built.

The design I've settled on is a massive compromise on a number of levels (cost, size and portability).

If I end up with enough bass but not a good enough treble (or it's not portable/small enough - I live in a small cottage down some steps from an unlit dirt track), them it'll be sold to part fund 2 O10.5 widebody cabs. If there's not enough bass, then add a sub. If there's not enough bass and/or treble then it's either an O15 (which is what I really want but I am very concerned about portabilty) or possibly one of our own Alex Claber's cabs if portability is still an issue.

TBH I'm not a huge fan of much treble in my sound and have wondered whether I'll use the piezos much at all.

I have even considered building it without tweets so I can have the horn centred in the cab (I think it would look tidier) and add a seperate piezo cube enclosure.

I'm going to go back to the plans to see if I can get a widebody cab out of one 8 X 4 sheet of ply though.

[thinman]

[quote name='clauster' post='255189' date='Aug 5 2008, 10:48 AM']I'm going to go back to the plans to see if I can get a widebody cab out of one 8 X 4 sheet of ply though.[/quote]

You can - I made mine the width of the crossfire version but with a straight 4 piezo array but you have to adjust the cut plan in places. If that's too bright you can always use the switch or use your EQ. If it's not bright enough an 8-element melded could be retro-fitted. Ididn't make a separate piezo box so had to ensure the backs were all sealed up with silicone - there's quite big gaps around the horn screws.

I didn't break my drivers in first and it was really noticeable how it improved with use so bear that in mind when you first use it.

Other tip from my mistake: If you're putting handles on the sides don't put them in the centre - they need to go further back so that it's balanced. It'll make it a lot more comfortable to carry.

I imagine with a Titan sub (which I'm just about to start on for PA use) you'd have to use a crossover and probably bi-amp given the impedances.

Good luck though.

PS Unless you're really tidy (which I'm not) get some latex gloves. That PL glue don't come off too easily and people look at you like you have some horrible disease.

Edited August 5, 2008 by thinman

[alexclaber]

[quote name='clauster' post='255189' date='Aug 5 2008, 10:48 AM']I live in a small cottage down some steps from an unlit dirt track)[/quote]

In light of that I'd be more inclined towards building the standard size Omni 10. It isn't a tiny cab at the best of times and adding an inch here or there could cause doorways and knuckles to have some nasty collisions. Bill himself has commented that the extra bottom from the larger cab size is marginal - and that extra bottom is only extra sensitivity in the lows, it'll still run out of excursion at the same SPL.

I wouldn't put the handles in until you've built the cab and found the balance points.

Good luck!

Alex

[clauster]

The widebody is out - I'm adding an extra inch to the depth (as a few peeps have already raised concers about breathing room for the driver, I know its okay at standard depth but what the heck, I've got enough ply) and I want to seal the piezos in in a David Perry stylee, so there just isn't enough plywood left. Plus I think I'd make a right mess of glueing the melded array (and am really not into treble on my bass in anycase).

Alex, thanks for the tip - I've been researching these cabs for months now and had already picked up on the balance issue. Plan is to do a dry run, find the CoG (in both directions) and route out rebates for the handles. Am going for sprung side handles, secured with bolts and t-nuts at the vertical CoG as well as depth for the occasions when the cab needs to be a one handed carry.

[alexclaber]

To expand on the larger internal volume thing, if you make the Omni 10 bigger then not only will you increase the internal volume but you'll lower the port tuning by a few Hz. My rough simulations suggest that although you'll gain 0.5dB at 50Hz increasing to just over 1dB at 40Hz, at 55Hz you'll be about equal and between 65Hz and 130Hz you'll be 0.5dB worse off.

With sprung side handles I imagine you'll often have to negotiate doorways sideways so depth matters.

Alex

[clauster]

[quote]With sprung side handles I imagine you'll often have to negotiate doorways sideways so depth matters.[/quote]

That's why I'm allowing for the occasional one handed carry - ie through doorways.

[gilmour]

TBH, I'm sure what ever you make will sound great, and you'll have a massive sense of satisfaction at the end of it. My step dad once said to me "making cabs is great, they always work, and always sound good, even if yo've only stuck a speaker in a box" I'm just jealous as I want to be building more cabs but my life keeps getting in the way

Edited August 5, 2008 by gilmour

[clauster]

Drivers (DL2510s) just ordered from Thomann

Remaining hardware to be ordered from Bluearan over the next few days.

Thanks for the encouragement Gilmour.

Alex, I realised this morning that the original cabinet volume can be preserved - I'm making a sealed chamber for the piezos, so I'll just add enough depth to make up the volume I lose there. Thanks for the results of your calculations though, I'm not bad on the electronics side of things but what I know about accoustics could be written on the back of a postage stamp.

Edited August 6, 2008 by clauster

[clauster]

I received my piezos this morning at 0:30!

They'd been delivered to my neighbour yesterday while I was at work. Wish I didn't have a couple of important meetings today so I could "work" from home and start cutting and glueing.

[planethead]

[quote name='clauster' post='256874' date='Aug 7 2008, 07:43 AM']I received my piezos this morning at 0:30!

They'd been delivered to my neighbour yesterday while I was at work. Wish I didn't have a couple of important meetings today so I could "work" from home and start cutting and glueing.[/quote]

I started my omni 10 yesterday and am now covered in glue!

Probably nothing new but this is what I've learnt in 24 hours.

1) if you don't have a table saw then the cutting guide and sled are a must
2) ensure your cutting surface is as stable and level as possible - my improvised support system means I now have to keep going back and shaving pieces off to make things snug
3) if you ignore 2) get ready to use more glue!
4) Found the horn panels and braces very tricky to clamp (note 3 above)
5) I could only get 12 mm (7) ply so I've had to move one of the horn panels slightly to preserve internal volume -
which I'm sure is OK (isn't it?)
6) that stuff about measure twice cut once - don't forget it ;-)

Not looking for enormous power handling so went with the 2010's and didn't bother with tweeters -
probably too old to hear anything above 500hz!!!
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(this statement is in fact a preamble to my latest gripe (cutting 'engineers' who insist on 're-mastering' old recordings by 'refreshing' the audio in order to add more HF than was ever intended)

- but I'm not hijacking your thread so... good luck with your build

TTFN

[thinman]

[quote name='planethead' post='257264' date='Aug 7 2008, 02:50 PM']I started my omni 10 yesterday and am now covered in glue!

Probably nothing new but this is what I've learnt in 24 hours.

1) if you don't have a table saw then the cutting guide and sled are a must
2) ensure your cutting surface is as stable and level as possible - my improvised support system means I now have to keep going back and shaving pieces off to make things snug
3) if you ignore 2) get ready to use more glue!
4) Found the horn panels and braces very tricky to clamp (note 3 above)
5) I could only get 12 mm (7) ply so I've had to move one of the horn panels slightly to preserve internal volume -
which I'm sure is OK (isn't it?)
6) that stuff about measure twice cut once - don't forget it ;-)

Not looking for enormous power handling so went with the 2010's and didn't bother with tweeters -
probably too old to hear anything above 500hz!!!
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(this statement is in fact a preamble to my latest gripe (cutting 'engineers' who insist on 're-mastering' old recordings by 'refreshing' the audio in order to add more HF than was ever intended)

- but I'm not hijacking your thread so... good luck with your build

TTFN[/quote]

Errm - what's wrong with 12mm 7-ply. That's what they're supposed to be built from.

Get some latex gloves for when using that glue or you'll look like something from Quatermass for about a week.

[clauster]

Cheers for the tips Planethead.

Most of that I had been aware of, but I can't see why you'd need the sled if you've got a guideboard and can do arithmetic. Am I missing something?

[planethead]

[quote name='clauster' post='257872' date='Aug 8 2008, 10:32 AM']Cheers for the tips Planethead.

Most of that I had been aware of, but I can't see why you'd need the sled if you've got a guideboard and can do arithmetic. Am I missing something?[/quote]

- being an instant gratification junkie myself (and certainly no woodworker) - they might be useful for others of a similar disposition

- its the 60 degree angle for the horn throat panels - having clamped them as per the instructions (in a Z shape) I thought I could cut with the guide board alone using the horizontal brace panel to slide the saw shoe along while the vertical blade renders the angle - but this left the saw too low - it just made cutting the angle much easier by screwing(temp) a piece of wood to the brace and then using the guide to run the saw along - which is exactly what the sled would have done had I had the foresight/patience to build one first.

+1 for latex gloves tip but don't call me Errm ;-)

TTFN

[clauster]

Cheers for that bit of insider info matey

[planethead]

[quote name='clauster' post='258023' date='Aug 8 2008, 01:02 PM']Cheers for that bit of insider info matey[/quote]

You are welcome... BTW if you discover a neat way to clamp the horn throat and brace section while gluing and screwing do let me know - this bit got me in to a right b*ggers muddle and covered in glue to boot!!

TTFN

Actually scratch that having thought about this and looked at the plans again I see where I went awry. The plans appear to suggest that the throat panel and baffle brace are attached and then the horn braces added. I see now that the horn braces should be attached to the throat panel and the baffle brace added afterwards.

Edited August 8, 2008 by planethead

[billynoband]

The guide boards, cutting sledge and circular saw are handy but if you are over 40 and was taught woodwork at school instead of design technology you may well be able to manage without.
I did both my BFM cabs with a handsaw and no clamps, there is always a way if you want to save money like I did. A spirit level, a set square and handsaw are enough if you build on a flat and level surface.

Good luck with the cabs and please keep us informed.

There is a good BFM presence over on [url="http://finnbass.com"]http://finnbass.com[/url]

[clauster]

Cheers Billynoband,

I joined Finnbass forum (and BFMs too) a little while ago as soon as my determination to build an Omni reached the point where I knew it was likely to become reality. Very helpful bunch on both sites (and here too of course). I've got the feeling by the end of the build there will be an "I'd like to thank.....without whom none of this would have been possible" post as the advice I've received and build diaries I've read have really heped me settle on the basic design of my first build.

[woodster909]

hi Clauster, how's the build coming on?

I've decided to build one of these when the temperature in the shed rises to something half decent

I've not done any woodwork since college many years ago, but that doesn't seem to stop anybody

more pics if you can please?!!

cheers

[clauster]

Beyond making a 4 element cut-and-glued straight piezo array there's no progress to report.

I've got all the bits, wood, paint and access to all the tools I need, but my work area is outdoors and every weekend since late August has either been busy, raining or too damn cold. Expect progress in the Spring.

On an ironic note, since making the piezo array, I've been using a cab with a tweeter at one of the rehearsal spaces I use and I always turn it off after a few minutes, so I think I'll be going tweeterless.