Northeast Region Sanford Sound Maine NESPL June 9

[sexiewasd 10+ year member]

This is probably due to tuning or phasing issues, and I doubt it reflects your true peak. Half wave of 20hz is @ 27 feet

Measure your cabin corner to corner (where the meter sits to furthest back corner) divide that by 1165 fps (speed of sound), then divide by 2 (half wave). This should be close to the target you want you peak.... The large SUV's generally peak in the high 40hz range.

I would say 150 is a good mark to shoot for. You will need to create a lot of sawdust to get there.

I tried that this time actually, and didn't really get the results I was looking for. The horn was tuned to 58.3hz (I doubt my cuts were accurate enough to bother with the .3), and thats what i did my run on. (second run was 20hz just because I knew it wasn't going to get any better than that.) It's 10 feet corner to corner. 1165 / 10 = 116.5 divided by 2 = 58.25 temperature and flex any box space probably threw that all off, but this time I'm going to try something different and go with what I can measure as a peak on a mic. I wish I had a real calibrated RTA to use, but I'm still new to this game so I figure I might as well try all the silly things I can and learn from it while I've got no shame.

 

[Kangaroux 5,000+ posts]

I tried that this time actually, and didn't really get the results I was looking for. The horn was tuned to 58.3hz (I doubt my cuts were accurate enough to bother with the .3), and thats what i did my run on. (second run was 20hz just because I knew it wasn't going to get any better than that.) It's 10 feet corner to corner. 1165 / 10 = 116.5 divided by 2 = 58.25 temperature and flex any box space probably threw that all off, but this time I'm going to try something different and go with what I can measure as a peak on a mic. I wish I had a real calibrated RTA to use, but I'm still new to this game so I figure I might as well try all the silly things I can and learn from it while I've got no shame.

I don't think temp would make your score change that much. As you get higher up in loudness it starts to count. Nothing wrong with running the A/c a little before your run, though

 

[sexiewasd 10+ year member]

Yea there is one little problem with that, it doesn't work, lol.

55 is a bit of a stretch without armor plating and bullet proof glass, but who knows? True horn has a lot of potential so if you could do compression chamber way at the back and have the mouth comppletely sealed off like a wall it would pobably be very efficient.
I do think the horn box was bad ***. Definitely performed well considering you only had 1 sub hooked up and how much power on tap.

3hp is good for 1500W music all day long povided you watch excursion.

Fun show though, shame I blew up both of my subs with a dismal number to show for it.

You called it, I just tore the box apart and took the cones off. Looks like a scraped a coil from over excursion @ 20hz. It's just a small scrape so i think it will be ok, but it's weaker now. Pretty sure i'm going to burn it next time. Maybe i can find some 15" cones to put on them.

 

[SPL Blazer 10+ year member]

I tried that this time actually, and didn't really get the results I was looking for. The horn was tuned to 58.3hz (I doubt my cuts were accurate enough to bother with the .3), and thats what i did my run on. (second run was 20hz just because I knew it wasn't going to get any better than that.) It's 10 feet corner to corner. 1165 / 10 = 116.5 divided by 2 = 58.25 temperature and flex any box space probably threw that all off, but this time I'm going to try something different and go with what I can measure as a peak on a mic. I wish I had a real calibrated RTA to use, but I'm still new to this game so I figure I might as well try all the silly things I can and learn from it while I've got no shame.

I really think your over thinking this a bit. Build a box of a normal size, and built to spec or just a little bigger. Depending on your goal, if your looking for musical and be able to burp it then tune the port to the mid to upper 30's and go from there. If your looking for musical only box and listen to rap and that other bass kinda music then tune to the low 30's. If it's gonna be for burps only then start the tuning in the low 40's and go up from there.

To be honest, competitors that put way too much thought into the science behind waves and such don't seem to hit as high as they want on the meter. I've talked to several over the years that know a lot about the physics behind audio, and always get beat by guys starting out that know nothing about it. Getting louder is all about testing and building different enclosures, testing various sub and amp combo's.

Leave the science of it all to the veteran competitors building Extreme class concrete filled bandpass vehicles and just have some fun and learn it all as you go.

 

[hispls 5,000+ posts]

Yea there is one little problem with that, it doesn't work, lol.


You called it, I just tore the box apart and took the cones off. Looks like a scraped a coil from over excursion @ 20hz. It's just a small scrape so i think it will be ok, but it's weaker now. Pretty sure i'm going to burn it next time. Maybe i can find some 15" cones to put on them.

The problem with tuning high 50's with the box you had is that the sound isn't coming from the back corner but the front so pathlength to the windsheild is very short then since the box isn't walled off from the back you get a wave bouncing off the back then up front so no telling what that's causing to gain and cancel. That method is quite accurate and I got it from a good source. Not a replacement for testing, but it gives you a ballpark of where you'll have an easier time getting a good peak.

Those coils will go for a while scuffed up, but will probably fail quicker, particularly if you keep rubbing them.

Robot Underground has OEM Audiopulse cones in 12 and 15" (also possibly 12" LA/honeycomb nomex), and OEM coils, and spiders for the 3hp, dunno if he has the LA style frames (assuming yours has the 4 side bolts to hold the top on that's easiest) or you'll have to buy some adapter rings and a TI frame. Will run you some money to recone those with OEM parts... Also there are some 15" TC proto plastic cones on here that look pretty sweet. Would be very unique.