What went wrong

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8th February 2006, 11:56 AM
greenie512

What went wrong

I’m hoping you finishing guru’s can explain what went wrong (if it actually did?) …
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I’ve just finished veneering some speaker cabinets with Silky Oak 1.5 mm thick ply/veneer and finished them with 3 coats of Organoil’s Interior clear finishing oil (with Tung Oil) - applied with a lint free cloth.
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If you look at the picture you’ll see “darker” areas around the port of the right speaker. This is less visible direct on but quite noticeable at an angle.
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Previously on American Rock Maple jobs, I never found it necessary to “wipe-off” as the oil seemed to absorb evenly – so I didn’t do any wipe off on this job – I just made sure I applied finish evenly and I didn’t spot any “pooling”.
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I didn’t spill any glue over this area and because of the thickness glue doesn’t seep up to face level?
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I’m really hoping it’s a “blemish” in the veneer and not my work???
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8th February 2006, 12:08 PM
Shedhand

In the veneer

Looks like a bit of wierd grain to me.:o Interlocked maybe?
Nice job though. Might redo my Krixes and Jamos.;)
Cheers
8th February 2006, 12:18 PM
Wood Butcher

I'd have to agree with Sheddie. I don't think that it is because of the oil, but rather because of the particular grain of the veneer.

Looks Great BTW :D
8th February 2006, 12:19 PM
Greg Q

That's no defect-that's a feature.

Hi...

It looks like a grain reversal area on that piece of veneer catching the light differently. If so I don't think there's any fix short of sealing the veneer and then staining heavily then refinishing.

Let others weigh-in first, but I think either learn to love it or re-do it.

I'll send you a PM.

Greg
8th February 2006, 12:36 PM
Shedhand

Quote:

Originally Posted by Wood Butcher

I'd have to agree with Sheddie. I don't think that it is because of the oil, but rather because of the particular grain of the veneer.

Looks Great BTW :D

G'day Woody. You little devil (all the 6's on that post):eek::eek::eek:
8th February 2006, 02:04 PM
AlexS

I'm sure Gregoryq's correct. Different grain direction will reflect the light differently. IMHO, it looks fine, don't change a thing. I'm not sure striiping, sealing & refinishing would make any difference.
8th February 2006, 03:30 PM
greenie512

Thanks

Thanks guys, I haven't done too much work with oil on veneer and hadn't see this before so was having a small panic that I'd screwed-up.

Also just posted these speakers on eBay

http://cgi.ebay.com.au/ws/eBayISAPI....MESE%3AIT&rd=1

So wouldn't like to be selling them with bad workmanship.
10th February 2006, 12:14 PM
soundman

just a tip greenie
either spray your stuffing black or put some black cloth over it where it can bee seen thru the bass port makes all the diference to prsentation.
the white looks out of place.
cheers
10th February 2006, 12:47 PM
Max Ripper

Normal

Looks like normal growth figures unless you had the speakers blasting while oiling, or that speaker was exposed to a cold wind etc and the other wasnt. I can see the same signs on the left speaker ... anyway they look magic mr %98 cheers.

Max Ripper who needs sound when the speakers are music to my ears
13th February 2006, 06:24 PM
Petebass

Greenie the cab's look nice. If I may, I'd like to comment a little on the speaker design. I apologise in advance if you've already accounted for these things:-

As you know, cab size an porting are very important in getting speakers to sound their best. A great speaker in the wrong cab can sound like garbage. Similarly a cheap speaker in a the right cab can sound surprisingly good.

I notice you've filled the cab with acoustic stuffing. It is with surprise that I read in the Ebay article that the cab size was slightly larger than anticipated, because the fibre stuffing means the speakers "see" an even larger cab again. It's always a good idea to line each wall with fibre to prevend sound waves from bouncing around inside the cab uncontrollably, but completely stuffing the cabs serves another purpose.....In practice, the stuffing means the sound waves hit the cabinet walls a few milliseconds later than they would have (as it would in a larger enclosure), effectively slowing the speed of sound inside the cabinet. As a rule of thumb, a fully stuffed cab cab have an effective increase in internal volume (Vb) of up to 30%. It also throws out your calculations for the tuning frequency of the porting.

Speaking of porting, I'd advise against letting the stuffing obstruct the port as yours appears to do. If the air moving in and out of the port can't flow freely, the port may not do it's intended job. The speakers may even start to behave as though they're in a sealed cab, which in itself isn't bad, but it's not what you were aiming for in your design.

Of course, all this is mute unless you used the exact same drivers that Omega used in their speaker. It's not uncommon for similar looking speakers to have completely different Thielle/Small parameters and therefore completely different optimal enclosure sizes and porting requirements.

I hope this doesn't come across as though I'm picking on you. I just thought some of my speaker design experience might come in handy.
13th February 2006, 08:29 PM
Clinton1

Nah, Petebass, you don't get off that easily. :D

Now that you have teased me by providing just enough info to be dangerous I think a lot more info should be forthcoming.

How about an article on speaker cabinet design for beginners?
13th February 2006, 08:40 PM
Petebass

Quote:

Originally Posted by Clinton1

How about an article on speaker cabinet design for beginners?

It's impossible to do without writing an entire textbook :)

Seriously though, I'm more than happy to answer questions, either in the forum's on via the PM feature.

Speaker cab building has always been a bit of a tricky subject because ususally the people who embrace the science of it aren't generally good at making things out of wood. I must admit I fit into this category (which is why I signed up to this forum), though I'm much improved over the years. With the woodworking talent I've seen on this forum so far, it's scary to think how good a result is possible with the applied science.
14th February 2006, 10:59 PM
soundman

Ist lesson in speaker design.
forget any thaughts that you might be able to do the maths manualy
Beg borrow or buy if you have to one of the modern speaker design programes like "base box pro"
these programes allow almost anyone to design a reasonably decent speaker box.
Admittedly it helps to have some understanding of what you are trying to do but there is even a speaker design primer in the included documentation.
cheers
15th February 2006, 01:23 AM
Spelunx

I put together a subwoofer from theloudspeakerkit.com, and it totally rattles the windows! You can get awesome performance for a fraction of the cost with DIY kits.

There is probably enough info on the website to have a red-hot go at making your own.
15th February 2006, 07:32 AM
Petebass

Yep those loudspeaker programes are a must. I like WINisd for beginners. All of them use the Thiele-Small parameters I mentioned earlier as a basis for their modeling, and all of them make assumptions regarding existing knowledge the sort of sound you're after. All of them are obsessed with delivering excessive bass frequencies , and virtually none of them account for speaker cone excursion.

At best, those programs can get you about 80% of the way there once you've selected your driver(s). However, driver selection is 90% of the challenge. And if you know what you're doing, you can manupulate the software, often in ways to make it do more than it was designed to.
15th February 2006, 09:29 AM
greenie512

Pete, I’d agree with your comments. If you read my advert on eBay I said “lightly filled”. In fact, the speaker chamber is broken down into 3 volumes with two internal ladder braces only 2 have fibre filling. The top speaker volume just as a “bit” of damping and the port volume just to discourage “kids” poking objects down the port!
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I auditioned no-fill and light filled combinations and the latter helped tamed the metal cone “analytical” presentation. I’ve found that such filling doesn’t have too much effect on a bass reflex design.
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Due to the physical build of these drivers it’s quite easy to workout the maker and model.
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Great to see there’s another speaker builder hanging out here … love to see some pictures of your projects.
15th February 2006, 12:59 PM
Petebass

Quote:

Originally Posted by greenie512

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Great to see there’s another speaker builder hanging out here … love to see some pictures of your projects.

I'm going to have to invest in a digital camera. The trusty SLR is great, but it's not practical in this day and age.

Most of my speaker are designed for bass guitarists but as it happens, I'm about to build a centre speaker for my home theatre. My girlfriend agreed to buy the bits and pieces as my valentines day present (how romantic). I might have to start a thread here and post pics, design notes etc..........
14th April 2006, 03:30 PM
Petebass

Quote:

Originally Posted by Petebass

Most of my speaker are designed for bass guitarists but as it happens, I'm about to build a centre speaker for my home theatre. My girlfriend agreed to buy the bits and pieces as my valentines day present (how romantic). I might have to start a thread here and post pics, design notes etc..........

OK it's finished. Check out the thread at:-

http://www.woodworkforums.ubeaut.com...d=1#post292604