Had some spare time...lol

[alexkerhead]

Ok, so everyone knows I have been wanting to start my large 2-way JBL DIYs, but I cannot afford the stuff todo it with yet, so last night when I had a couple of spare hours, I decided to make a set of small DIYs to hold me over until I can get the stuff for my JBL large DIYs.

With these I used the advent fried egg tweeter, the only good tweeter they ever produced...IMO.
I used a JBL 5" mid-bass from those crappy bookshelf speakers they made.

These enclosures I made are approx one cubic foot in volume sealed.
Sealed with wood glue and silicone sealer.

I know they aint purty, I only have a jig saw until I can afford a table saw motor.

A good sanding should perk them right up.

Yes, I am shocked all the joints are flush as well..

Unfortunately I mounted one of the tweeters a tad lower than the other, but I think I can fix that.
Each one is filled with approx 2 handfuls of polyfil from a old woofer box I made.

The bass is a bit weak, but it is only a 5"mid-bass, but you can still feel it in the floor at higher levels.
High frequency is nice, better than I expected. I used a 14uF capacitor on the advent tweeter to get the level of high I wanted.

They will get a black carpet treatment sometime.

Keep in mind, this was just for fun, not serious(no planning or such), so don't roast me to badly..

[grumpy]

Looks like you had some fun putting those together.
Is the cab volume similar to the box the 5" driver came from?

-grumpy

[alexkerhead]

Looks like you had some fun putting those together.
Is the cab volume similar to the box the 5" driver came from?

-grumpy

Tons of fun, sometimes ya gotta just experiment. Planning and preperation take a lot of the fun away.

10" wide, 8.5" deep, 13.5" Tall External parameters.
8.5" wide, 7" deep, 12" tall internal parameters.
I would say a good bit more than the original boxes, but it has been a while since I have seen those models. I pulled the mid-basses out several years ago.
They came from some Ti bookshelf JBLs that were just destroyed and the titanium tweeters were shot..

Original boxes were ported with small 1.5" ports I believe. But seeing zilch have so much luck with sealing, I thought i'd give it a go.

The advent tweeters I bought a while back when I thought one of my tweets were bad in my large advents, turned out to be bad capacitor, so I replaced it and had spare tweeters for play.

[Zilch]

Original boxes were ported with small 1.5" ports I believe. But seeing zilch have so much luck with sealing, I thought i'd give it a go.

The "luck" I've been having has been with using the small group of JBL drivers suitable for closed-box alignments:

http://audioheritage.org/vbulletin/s...ad.php?t=12036

Another part of the fun is measuring the drivers' T/S parameters to discover which ones will work best, easily accomplished with WT2 or simple electronic "tools." All you need is Fs and Qes (or Qts, as estimate) to calculate EBP (Fs/Qes) to know.

[50 or less is good to go.... ]

[alexkerhead]

I wish I had the software and mic to do the emasurements, but that is out of the question for now.
All I havebesides your assitance is experimentation.

My basis basically is:
If the drivers you are using dont work well in the box you made, then there is a driver somewhere that will work well.

Kind of a hit and miss, but I came out on top with this project.

As you have pointed out before, I can recognize a flat response generally and think these DIYs have good response from 60Hz to 15KHz. They are very driver limited. 5" mid-bass and advent tweeter.

Although I think MDF would have had better acoustic properties, I need to keep saving my money for the real deal you have been generously assisting me with.

[Zilch]

I wish I had the software and mic to do the emasurements, but that is out of the question for now.

Actually, these particular measurements can be made with tools you already have: signal generator, voltmeter, a couple of resistors.

Put Vance Dickason's "Loudspeaker Design Cookbook" (7th Edition, min) on your holiday gift wish list. Also, Joseph D'Appolito "Testing Loudspeakers."

The more you experiment and learn, the more useful they become. There's an entire chapter in Dickason on closed-box alignments, plus one of his DIY project speakers, some mini-monitors.

[Your new PT waveguides are in the mail, BTW.... ]

[alexkerhead]

Actually, these particular measurements can be made with tools you already have: signal generator, voltmeter, a couple of resistors.

Put Vance Dickason's "Loudspeaker Design Cookbook" (7th Edition, min) on your holiday gift wish list. Also, Joseph D'Appolito "Testing Loudspeakers."

The more you experiment and learn, the more useful they become. There's an entire chapter in Dickason on closed-box alignments, plus one of his DIY project speakers, some mini-monitors.

[Your new PT waveguides are in the mail, BTW.... ]

Will do!

Thanks zilch!
Cannot wait to see those things!
Will be my first step into the world of true hi-fi.

I think this project and the cheap DIYs only solidified my belief a good 2-way sound much more correct than a good 3-way.

Suprisingly, these home-made redneck 2-ways get VERY loud without distorting!