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3pi 4pi? [message #75040] Mon, 24 December 2012 08:44 Go to next message
my0x is currently offline  my0x
Messages: 23
Registered: October 2012
Location: Philadelphia, PA
Chancellor
What are some of the more subtle differences between the 3pi and 4pi when built with the AE 12s or JBL 2226, respectively? It seems the 3pi may have a little more frequency extension, and the 4 pi a bit smaller cabinet and higher efficiency. I am also looking to know what might work best with my existing Hagtech Cymbal 8w p/p monoblocks. I know that all of the Pi's will reach ear bleeding levels in my house, but have read that the 4pi's can take a little more juice to come 'alive'. These are for music only, at reasonable levels...Jazz, symphonic, quartets, classic rock.

Initially, I was considering building the 6pi because I have good corners available, but when I showed my wife a 3d mockup in our 13 x 24 x 9 living / dining room, it didn't really fly to well...mainly because of the size of the midrange horn and whole vertical stack. I read that Wayne had experimented with a 2-way version of the corner speaker in the evolution of the and 7pi, and that might also sound interesting to pursue.

Speakers will be at the 13' width of our combination living / dining room...and run without subs.

Looking to hear some opinions / comparisons!

Thanks,

m@
Re: 3pi 4pi? [message #75041 is a reply to message #75040] Mon, 24 December 2012 09:19 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

Here are a few links that may be helpful:

Re: 3pi 4pi? [message #75042 is a reply to message #75040] Mon, 24 December 2012 14:13 Go to previous messageGo to next message
rkeman is currently offline  rkeman
Messages: 78
Registered: March 2010
Location: Florida
Viscount
If you have the corners, the 6Pi or 7Pi is definitely the best option. The midrange horn controls dispersion into the upper bass and really smooths the room response. The 3i is excellent, but the 6Pi is better still. Finish the speaker in a color or veneer to blend into the decor and perhaps your significant other will be more amenable to the unique design. Bribery and begging can also be effective in some cases. Good luck!
Re: 3pi 4pi? [message #75117 is a reply to message #75042] Tue, 01 January 2013 13:42 Go to previous messageGo to next message
my0x is currently offline  my0x
Messages: 23
Registered: October 2012
Location: Philadelphia, PA
Chancellor
Happy New Year!

Thanks both for your replies and encouragement...very helpful. I recently came across a pair of good JBL 2226h's measuring 5.0 and 5.1 respectively across their voice coils that were hard to refuse, so I will begin this journey with the 4pi's.

Wayne, would you be so kind as to send me the 4pi plan? Although I want to see first what I might have in my parts bin compatible to build the crossovers, would you consider selling a 4pi kit minus woofers?

Since I'm not going to run high power (<10 W) through the crossover, is there any benefit to using smaller high quality resistors where you typically show multiple resistors for high power dissipation?

Thank you,

Matt
Re: 3pi 4pi? [message #75126 is a reply to message #75117] Tue, 01 January 2013 16:39 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

You've got mail!

We don't sell partial kits, but we do sell crossovers and waveguides by themselves for people that want to source their own drivers.

You can use resistors with lower dissipation capacity, but I would discourage you against it. They're just not that expensive. Get Mills resistors if you want, but don't skimp, they don't cost that much.

Re: 3pi 4pi? [message #75307 is a reply to message #75126] Mon, 21 January 2013 10:45 Go to previous messageGo to next message
my0x is currently offline  my0x
Messages: 23
Registered: October 2012
Location: Philadelphia, PA
Chancellor
The JBLs came in and seem really nice. This project will be a HUGE departure from the fostex fe206e based full rangers ... Each woofer has 3.5x the surface area of any woofer I've used in the past! Slowly unloading some other gear, then will not skimp on other parts.
Re: 3pi 4pi? [message #75309 is a reply to message #75307] Mon, 21 January 2013 11:29 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

Keep us posted on your progress! And don't skimp on the pics!

Re: 3pi 4pi?-->4pi w JBL+B&C [message #77136 is a reply to message #75309] Fri, 05 July 2013 08:57 Go to previous messageGo to next message
my0x is currently offline  my0x
Messages: 23
Registered: October 2012
Location: Philadelphia, PA
Chancellor
I've eagerly been following some other recent build threads while I've been getting my 4 pi project together. Here is a progress report so far:

Keeping costs down: 3 or 4 months ago I was on the fence about 3pi or 4pi. I decided to go the 4pi route when I came across a pair of used JBL 2226's on ebay for around 250, shipped to my door. I figured that even if they were toast, I could re-cone them with JBL cones and I would still be way ahead of the impressive price tag they carry when new. Since this seller had 8 2226's he was selling, I had him send me the closest matching pair of the lot. I was pleased when they arrived. Despite being dusty and slightly faded from more on one side than the other, they measured 5.3 and 5.4 ohms impedance, and test tones played through each didn't raise any alarms.
For a little bit, I chased after a pair of JBL 4725's for $600 from a local craigslist as it not only has the JBL 2226h woofer but the famed 2426h compression driver as well. I was wary when the seller who was eager to unload them took a while to inform me that one of the woofers had been rebuilt and didn't know if it was OEM. If you can get them at a good price and they aren't thrashed, you have sourced all 4 drivers needed for your 4 pi's if you want to go the all JBL route.


index.php?t=getfile&id=1208&private=0



Building the cabinets: I built the cabinets with fully biscuited 3/4" mdf panels. The biscuits ensure panel alignment when gluing up and add strength to the final cabinet. Someone gave me a cheapo 10" ryobi table saw a while ago- don't even bother with anything like this. While it is fine for ripping things down for some house projects, it is not a precision tool, even with the crosscut jig I built for it. On top of that, it is light and has to be supported from falling over when mounted to it's legs. I ended up using my buddy's saw with a 4' wide plinth, good runoff table, and a long fence that actually squares. All of the panels were accurately cut within 45 minutes. Use lots of clamps and excessive glue - the glue that squeezes out is easily scraped and sanded down when dry. It also ensures a sealed cabinet when building flush panels. After getting rid of the assembly glue, I squeezed a bead on the inside seams of both cabinets to make sure it's doubly sealed. Use a vacuum attachment to the biscuit joiner and the router - usually a cheap adapter piece for any shop vac will do. This helps keep the tool's cutting area clear, your shop area clean, and your lungs and eyes happy. 80 some biscuits = 160 cuts = lots of nasty mdf dust.

The r-13 insulation wasn't as bad as I thought it might be to work with. Just make sure to be covered head to toe and use long gloves. It cuts easily and staples into the cabinet and your done.



index.php?t=getfile&id=1209&private=0



I cut gaskets from pvc shower pan liner, and t-nuts for attaching the drivers to the cabinets. I don't have the compression drivers or crossover bits yet, but I will in a couple of weeks. I intend to cover the MDF panels fully with KD-Panels veneer panel which is a 1/8" veneered plywood, and make full grills with speaker cloth ala the late 1960's AR-5's and AR-7's I used to have. Kind of old school, but I really enjoyed that look and will protect the drivers from dust, cat hair, and curious visiting tiny hands. I'll also make an overlay panel for the front to have a flush finish at the face of the drivers.


index.php?t=getfile&id=1210&private=0



Managing expectations and budget: My hobbies are supported in our house, but with a new rule: find a new home for my old project or gear before I start on three new ones and leave two on the workbench. It's a lifestyle change for the better. I'm more apt to do more research and take my time working on something through completion, and the workbench or living room isn't so crowded. Despite the 'wall of speaker' in my living room at the moment, the Decware HDT's I built some years ago have a new home waiting for them, and their proceeds will fund the B&C compression drivers and high quality crossover components.

At the moment, I've clamped a panel into the hole for the high frequency driver so I can test the cabinet so far---far more even and constant bass response than the HDT...and just so much more below 80 hz! Looking forward to the completion of this project!






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Re: 3pi 4pi?-->4pi w JBL+B&C [message #77141 is a reply to message #77136] Fri, 05 July 2013 09:57 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

Just wait 'til you get those waveguides mounted!

Re: 3pi 4pi?-->4pi w JBL+B&C [message #77174 is a reply to message #77141] Thu, 11 July 2013 16:45 Go to previous messageGo to previous message
Nelson Bass
Messages: 39
Registered: November 2012
Baron
I second that as a former owner of HDT & ZOB...

The 4pi built to the specifications using JBL 2226H and B&C drivers is second to none IME.
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