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RichardH

DIY cabs

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[quote name='stevie' post='418272' date='Feb 24 2009, 12:18 PM']Nice work. I'd just mention though that three-inch ports will normally make an awful lot of wind noise in that size of cab. You might consider increasing them to 4".[/quote]

Not much that I can notice, but maybe I'm deaf :)

[quote name='stevie' post='418276' date='Feb 24 2009, 12:21 PM']With the Eminence Beta in there it will doubtless be singing the One Note Samba. ;)[/quote]

:P

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[quote name='Happy Jack' post='417881' date='Feb 23 2009, 09:25 PM']126dB?



I said [size=7]126dB?[/size]



Mad, ye're all mad, I tell ye.

;)[/quote]
I am. :P

This isn't by any means a flat response of 126dB over a wide range, it's a single peak. It's a very un-flat frequency response, the very antithesis of BFM's and Alex's designs :) It's not a perfect solution to anything, it's a very compromised and badly designed cab (hence Stevie's comments), but to my ears it sounds good so that's all that really matters. Quite tempted to build a 2nd one to have a nice 2x15 matching rig. In fact, I have enough plywood left....

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[quote name='Merton' date='Feb 24 2009, 12:50 PM' post='418315']
............ it's a very compromised and badly designed cab (hence Stevie's comments)

I didn't mean to suggest that your cab was badly designed - far from it. It looks good to me. It's just that the Eminence Beta will sound boomy in virtually any box you put it in. But you've modelled it - you know that.

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[quote name='stevie' post='418373' date='Feb 24 2009, 01:42 PM']I didn't mean to suggest that your cab was badly designed - far from it. It looks good to me. It's just that the Eminence Beta will sound boomy in virtually any box you put it in. But you've modelled it - you know that.[/quote]
Sorry, didn't mean to make it sound like I thought you were criticising me either!! When I say "badly designed" I mean in terms of size/driver choices ;) Yes, it's boomy, but in this box it's boomy in quite a musical way (IMO), hence why it can get so loud without too much trouble. If that makes sense..?

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I'm a prune. 126dB isn't 1W @ 1m, it's with 350W input power @ 1m. Which is silly and rather unlikely. The 1W @ 1m peak SPL is 102dB, that reads much more normal. (I was getting confused, hadn't looked at WinISD for a few weeks and was recalling the wrong figures..)

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[quote name='Merton' post='417814' date='Feb 23 2009, 08:28 PM']The LH500 makes it sing...

[attachment=20981:DSC00256.JPG]

So, first tests have proved it's going to sound good, now all I need to do is:

1) finish bracing the inside
2) re-check the airtightness of the box
3) line the interior walls with wadding
4) cover the cab
5) make the vinyl-weave grille frame (metal circle is added foot protection :D )
6) add feet and corners

...then I can recheck its performance :rolleyes:

I reckon it'll weigh in at about 18kg, we'll see...

Expect it to be finished in about 6 months.... :)[/quote]

Hey Mert,

I think it looks pretty cool uncovered and grungy! Does it really need to be airtight? If its well braced, and any gaps are less than the wavelength then surely you'll be alright?

I think, but dont quote me on this, the maximum wavelength of an audible sound is around 10mm or so?

Hmm, not sure about this now...

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Definitely needs to be airtight because otherwise the compression and rarefaction caused by the driver's movement will result in hissing/whistling as air is blown out of or sucked into the cab.

Alex

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[quote name='alexclaber' post='429353' date='Mar 9 2009, 01:42 PM']Definitely needs to be airtight because otherwise the compression and rarefaction caused by the driver's movement will result in hissing/whistling as air is blown out of or sucked into the cab.

Alex[/quote]

Cheers Alex, That makes sense!

I was thinking from my limited understanding of RF electromagnetics, which behave totally different.

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[quote name='Mikey R' post='429345' date='Mar 9 2009, 01:37 PM']I think, but dont quote me on this, the maximum wavelength of an audible sound is around 10mm or so?

Hmm, not sure about this now...[/quote]

The wavelengths of the audible frequency range from 17.2m at 20 Hz up to 17.2mm at 20 kHz.

If you feel the need to know the wavelength of any given frequency, then divide 344 (the speed of sound in m/s) by the frequency to get the wavelength in metres.

Andy

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[quote name='Mikey R' post='429345' date='Mar 9 2009, 01:37 PM']Hey Mert,

I think it looks pretty cool uncovered and grungy! Does it really need to be airtight? If its well braced, and any gaps are less than the wavelength then surely you'll be alright?

I think, but dont quote me on this, the maximum wavelength of an audible sound is around 10mm or so?

Hmm, not sure about this now...[/quote]
Cheers dude! Liking the 5er by the way - will get the pics over here later :)

This cab is now definitely airtight, this weekend coming I hope to finish radiusing the corners in preparation for the covering, and make the frame for the vinyl weave grille. Wadding will be the last thing to go in, probably in around 3 years after I've recovered from the birth of miniMert (4 1/2 weeks and counting :rolleyes: )

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Well, MiniMert was due to arrive yesterday...

...he didn't.

So today I did all the stuff I said I was gonna do last month, except the fabric weave grille, coz I did it twice and it looked sh*t both times. So here it is, without the front grille but I'm quite liking the utilitarian look. It needs some cleaning up mind.... The stuff used to glue the vinyl tot he wooden cab is f**king nasty!

[attachment=24023:DSC01681.JPG]

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Fabric weave grille looked sh*t, so I painted the speaker baffle. Colour courtesy of my 5 year old step-daughter Sophie:

[attachment=24345:DSC01697.JPG]

Shoulda painted the baffle before I did all the covering of course, but that ruins the fun :)

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[quote name='Merton' post='471734' date='Apr 24 2009, 05:20 PM']Fabric weave grille looked sh*t, so I painted the speaker baffle. Colour courtesy of my 5 year old step-daughter Sophie:

[attachment=24345:DSC01697.JPG]

Shoulda painted the baffle before I did all the covering of course, but that ruins the fun :)[/quote]

very nice! So is the covering painted blue too?

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[quote name='Mikey R' post='473807' date='Apr 27 2009, 10:30 PM']very nice! So is the covering painted blue too?[/quote]
Not yet.... but i suppose I could... :)

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Thinking of making myself a 2x15 cab, currently using 2 1x15 peavey cabs fitted with black widows. But the cabs are heavy and im sure to big, the cabs are 19" deep which im sure is a good 3" deeper than the older peavey cabs.

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Put this together over the last couple of days using 12mm wbp ply and 20x20mm bracing. Not going to cover it until ive used it in a band rehearsal on monday. Had a few rattles yesterday from it but have since braced the inside back. Dimensions are roughly the same as a late 80'2 early 90's 2x15 peavey 215d bw cab. weight wise i'd say it was around 55-60lbs. A lot lighter than th 79lb 1x15's ive been using.

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It seems that you have a lot of experience in woodworking tasks. Anyway, I see your work and I amaze with the outcome of you work. I am interested to make my own cabinet for my speakers with the profound foundation.

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I guess I can walk into the club... this is the 5th cab I build but ended up selling the other ones but two (small PA cabs with Beta12LT). :)

[attachment=61556:SUC53061.JPG]

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Of course you'd need to correct for barometric pressure and humidity as well... :-)

Runs and hides....



[quote name='Alien' post='431424' date='Mar 11 2009, 01:44 PM']The wavelengths of the audible frequency range from 17.2m at 20 Hz up to 17.2mm at 20 kHz.

If you feel the need to know the wavelength of any given frequency, then divide 344 (the speed of sound in m/s) by the frequency to get the wavelength in metres.

Andy[/quote]

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Boy am I intruiged by this discussion! If fello were want to try his hand at this caper, what all would he need to consider?

I understand the obvious wood choices etc. but what about speaker choices?

Do I need to understand how sound waves work? What impact does the cab/bracing have on the sound/tone of the of the build? What about Air flow? Or is it a matter of chucking 6 bits of wood together and cutting a few holes?

I am oblivious, sorry.

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I made this a few months ago (the cab, not the head :)):



Full thread here - [url="http://basschat.co.uk/index.php?showtopic=91802&st=0&start=0"]http://basschat.co.uk/index.php?showtopic=...t=0&start=0[/url]

Perfect for what I use it for and only weighs about 10kg. Thinking of doing another if/when a couple of cheap 12" drivers come up for sale.

Edited by Dubs

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[quote name='Phil-osopher10' post='995996' date='Oct 21 2010, 02:35 PM']Do I need to understand how sound waves work? What impact does the cab/bracing have on the sound/tone of the of the build? What about Air flow? Or is it a matter of chucking 6 bits of wood together and cutting a few holes?[/quote]

There is pretty deep science at the fine end of this. But the main stuff is learn use WinISD pro to sort the bottom end tone (and this includes air flow, it can tell you how big ports you need and how fast the air in them is going), and stiffness and non-resonance is the aim of bracing. Plus there is lining and stuffing tat break up air resonances and destructive reflections. But yeah, chucking together 6 bits of wood and some holes can work pretty fine, the cab industry worked fine on that until the 70s or so.

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Dubs, you cab looks exactly the kind of thing I could use for a jam night where no bass amp is provided & the PA/guitar amps are too precious to allow a bass to plug in. Any chance of stealing your dimensions / cutting list so I can have a go at making something similar?

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[quote name='Jean-Luc Pickguard' post='1005098' date='Oct 29 2010, 12:53 PM']Dubs, you cab looks exactly the kind of thing I could use for a jam night where no bass amp is provided & the PA/guitar amps are too precious to allow a bass to plug in. Any chance of stealing your dimensions / cutting list so I can have a go at making something similar?[/quote]

Yeah sure, I don't have the dimensions I used written down anywhere still but I can take measurements and from that I'll know exactly what it was. I tuned it too low though by about 5-10hz I think so I'll PM you some amended dimensions - same size cab, slightly smaller port. That's just how I work - very rough and ready, little/basic science :) It's all trial and error. I also don't have the patience to build something really intricate like a BFM design.

The cab sounds ok/good, but with a slightly higher tuned port it should sound a bit tighter. I'm actually considering building a matching 2x8 sealed vertical array cab to go on top of the 1x10. This should brighten up the whole sound and give loads more volume - easily enough to gig with.

Edited by Dubs

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thanks Dubs, that would be much appreciated. When I get around to building my cab I'd probably add a bit on top to attach my LMII and go for a vintage look with tolex, silver cloth & metal corners.

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