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Peavey 2x15 Project - Complete

#21
Since I've now taken the time to measure it, and we're talking about ports, maybe someone can help check my math. Using WinISD:

This is "per 15", as they are each in their own chamber inside the cab.

Knowns:
Driver: Eminence Legend CA154
Internal Box Size (inches): 12x24x18.5
Port Shape: Triangle
Port Measurements (inches): 7x7x9
- For the software, I used a square shaped port, 4.9x4.9" to approximate the triangle port
Port Diameter (inches): 24.5 <--- feel free to confirm this
Current Port Depth (inches): 3/4
Tuning: 41.88Hz <--- also looking for input here

From the Software:
Vent length: 1.39 in
Vent mach" 0.09 <--- what is this?


ASSumptions & Questions
Am I correctly interpreting what the software is saying on port length (I need one 1.39 inches long)?
If so, is it really worth extending the port by about an inch over what is there now?
If I do extend the port, what material should I use?

Doing a more simple calculation on this page (Invalid Link Removed) gives me a port length of 8.44 inches. Now I'm confused.
 
#22
So I shared this thread with a friend of mine who is very knowledgeable in the car audio arena (built competition cars) and he suggested starting with a 9" length port and adjusting it from there, which jives with the second calculator I used. I guess I just don't understand WinISD.

How does that look to you guys?
 
#23
Taking out 10% for your driver, bracing and eventual port, that's about 2.78 cu.ft. Use that as your box volume in WinISD. Tuning will likely end up closer to 40 than 50 but adjust it so the bump on the lower end is somewhere around +2db. If it gets over +3, it could start to have boom issues in bad rooms.


"Vent mach" is the air velocity in the port but that term is from the old WinISD program. Download WinISD Pro Alpha and use that. Much more detailed.
 
#24
Thanks for the information. I've been playing in Pro Alpha now and I'm trying to make sense of things. My graph doesn't really have a "bump" on the lower end, and I think a lot of that is due to my box volume.

Playing around and pressing buttons, if I do a .75" port (what I have now, the tuning frequency jumps to 72.03.

http://teamziptie.com/peavey/shortport.png

If I set that frequency to 40, the graph smooths out and port length is now 9.58".

http://teamziptie.com/peavey/longport.png

I assume the latter is better, but I don't see this "bump" I feel I should be looking for.

Sorry for the crummy screen shots.
 
#25
The bump is that rise in response centered around 100hz that goes way above the red line in the 72hz tuning example. It's gone in the 40hz example. I'd probably tune that one around 44-45hz. Should be a decent balance between good lowend output without getting too boomy.
 
#27
Whoa... you did all THAT in the space of one day (a Saturday)? You sure do work quickly. I got a good chuckle from the "88 MPH" sprayed on the 'guitar case'... No doubt you are fond of the "Back To The Future" series. Now.. I can't fathom why you "hate" the look of the old-school Peavey cabs. I actually cringed when I saw the mods you made to it. Seeing those those big "Peavey" logos and the classic metal accents on an amplifier backline is pretty exciting. If that had been my cab, I would have just removed the grime, painted the grill semi-gloss black and simply enjoyed it. But a very sweet wiring mod you made for sure!
 
#28
Rattman said:
Whoa... you did all THAT in the space of one day (a Saturday)? You sure do work quickly. I got a good chuckle from the "88 MPH" sprayed on the 'guitar case'... No doubt you are fond of the "Back To The Future" series. Now.. I can't fathom why you "hate" the look of the old-school Peavey cabs. I actually cringed when I saw the mods you made to it. Seeing those those big "Peavey" logos and the classic metal accents on an amplifier backline is pretty exciting. If that had been my cab, I would have just removed the grime, painted the grill semi-gloss black and simply enjoyed it. But a very sweet wiring mod you made for sure!
Click to expand...

The Peavey logo/look would certainly work for the 1980's throwback, but that was just a little too much for me.

I have some new grill cloth on the way. It will certainly be different, but hopefully cool. Should have that done by the end of the week.

Thanks for the compliments (even if you don't like the aesthetic)!
 
#29
So maybe the "complete" part wasn't quite true. Port construction started tonight.

ports.jpg


Any budding cabinet builders/modders out there, do yourself a favor and stick with round ports. Making triangle shaped ports is a pain in the ass.

I'm using the cab as my main clamp, and have the first have glued and drying. Once that part is dry, I'll pull them out and glue them up all the way. Then they'll get glued and stapled into place.

Total port length is 9 inches, which should put the cab right around 41Hz.
 
#30
Hard to tell in the pic but are you using the INSIDE of the triangle cutouts in the baffle to hold together the OUTSIDE of the port extensions you're building? If so, you're shrinking your port area by the thickness of the material used to make the extensions. Better plug the new interior port dimensions in the model and re-calculate. If that's not what's going on there, it's all good.
 
#35
sweet peavey retrofit. i just finished a peavey redo myself. i don't have work-in-progress pics, but a side by side pic. the post is "4x10 project finished" i hate those (IMHO) damn ugly aluminum trim pieces too.
 

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